阅读说明：本技术 经由多个流体泵的流体流动控制和输送 (Fluid flow control and delivery via multiple fluid pumps ) 是由 J·E·安博罗西娜 B·G·鲍尔斯 于 2018-03-19 设计创作，主要内容包括：本发明涉及一种流体输送设备,其包括控制器硬件、隔膜泵、正排量泵以及在隔膜泵与正排量泵之间延伸的流体导管。在操作以及将流体输送至下游接受者期间,控制器硬件将流体从流体源容器吸入隔膜泵的腔室中。控制器硬件将压力施加到隔膜泵的腔室,以将隔膜泵的腔室中的流体向下游通过流体导管输出到正排量泵。在向腔室施加压力以及将隔膜泵的腔室中的流体向下游输出期间,控制器硬件激活正排量泵以将流体从正排量泵泵送至下游接受者。(The present invention relates to a fluid delivery apparatus that includes controller hardware, a diaphragm pump, a positive displacement pump, and a fluid conduit extending between the diaphragm pump and the positive displacement pump. During operation and delivery of fluid to a downstream recipient, the controller hardware draws fluid from the fluid source container into the chamber of the diaphragm pump. The controller hardware applies pressure to the chamber of the diaphragm pump to output fluid in the chamber of the diaphragm pump downstream through the fluid conduit to the positive displacement pump. During the application of pressure to the chamber and the output of fluid downstream in the chamber of the diaphragm pump, the controller hardware activates the positive displacement pump to pump fluid from the positive displacement pump to a downstream recipient.)

1. A method, comprising:

drawing fluid into a chamber of a diaphragm pump;

applying a positive pressure to the chamber of the diaphragm pump to output fluid in the chamber of the diaphragm pump downstream through a fluid conduit to a positive displacement pump; and

activating operation of the positive displacement pump to pump fluid received at the positive displacement pump to a recipient during application of the pressure to the chamber of the diaphragm pump and output of fluid in the chamber downstream to the positive displacement pump.

2. The method of claim 1, wherein the positive displacement pump is a peristaltic fluid pump including a peristaltic pump element in sweeping physical contact with a section of the fluid conduit that is an elastically deformable portion of the conduit driven by the peristaltic fluid pump, the peristaltic pump element restricting downstream flow of fluid received from the diaphragm pump through the section to the recipient.

3. The method of claim 2, wherein a pressure of fluid in a first portion of the fluid conduit upstream of the peristaltic pump element between the peristaltic pump element and the diaphragm pump is different than a pressure of fluid in a second portion of the fluid conduit downstream of the peristaltic pump element between the peristaltic pump element and the recipient.

4. The method of claim 2, further comprising:

measuring a rate of fluid driven downstream from the chamber of the diaphragm pump to a section of the fluid conduit; and

controlling a speed of moving the peristaltic pump element to deliver the fluid to the recipient at a desired flow rate.

5. The method of claim 1, wherein drawing the fluid into the chamber of the diaphragm pump comprises: periodically receiving an amount of fluid into the chamber of the diaphragm pump from a fluid container, the fluid container being positioned differently relative to the chamber of the diaphragm pump.

6. The method of claim 1, further comprising:

measuring a rate of fluid driven downstream from the chamber of the diaphragm pump to the positive displacement pump, the positive displacement pump blocking flow of fluid received from the diaphragm pump; and

using the measured rate of fluid, the delivery of fluid from the positive displacement pump to the recipient is controlled as specified by a flow rate setting.

7. The method of claim 1, further comprising:

temporarily varying the pressure in the chamber to measure the rate at which the fluid is delivered downstream from the chamber to the positive displacement pump.

8. The method of claim 1, further comprising:

controlling the positive displacement pump to provide a continuous flow of fluid from the section to the recipient in a time window; and

temporarily adjusting a magnitude of a pressure applied to the chamber of the diaphragm pump during each of a plurality of measurement windows occurring within the time window to measure a respective portion of fluid remaining in the diaphragm pump.

9. The method of claim 8, wherein temporarily adjusting the magnitude of the pressure comprises releasing a gas from the diaphragm pump, the gas generating the pressure applied to the chamber.

10. The method of claim 9, further comprising:

calculating a rate of fluid delivered by the positive displacement pump to the recipient using respective measured portions of fluid remaining in the diaphragm pump measured during the plurality of measurement windows.

11. The method of claim 10, wherein the positive displacement pump includes a corresponding peristaltic pump element in physical contact with a section of elastically deformable conduit, the pump element restricting flow of fluid received from the diaphragm pump through the segment.

12. The method of claim 1, further comprising:

drawing fluid received from the diaphragm pump from a fluid source into the chamber of the diaphragm pump during a condition in which a peristaltic pump element of the positive displacement pump in physical contact with an elastically deformable section of a fluid conduit blocks flow of the fluid through the elastically deformable section.

13. A fluid delivery apparatus, comprising:

a diaphragm pump;

a positive displacement pump;

a fluid conduit extending between the diaphragm pump and the positive displacement pump; and

controller hardware operable to:

drawing fluid into a chamber of the diaphragm pump;

applying pressure to the chamber of the diaphragm pump to output fluid in the chamber of the diaphragm pump downstream through the fluid conduit to the positive displacement pump; and is

Activating the positive displacement pump to pump the fluid from the positive displacement pump to a recipient during the applying the pressure to the chamber and outputting the fluid in the chamber downstream.

14. The fluid delivery device of claim 13, wherein the positive displacement pump is a peristaltic fluid pump comprising a peristaltic pump element in sweeping physical contact with the elastically deformable section of the fluid conduit, the peristaltic pump element operable to restrict downstream flow of fluid received from the diaphragm pump through the elastically deformable section to the recipient.

15. The fluid delivery device of claim 14, wherein a pressure of fluid in a first portion of the fluid conduit upstream of the peristaltic pump element between the peristaltic pump element and the diaphragm pump is different than a pressure of fluid in a second portion of the fluid conduit downstream of the peristaltic pump element between the peristaltic pump element and the recipient.

16. The fluid delivery apparatus of claim 14, wherein the controller hardware is further operable to:

measuring a rate of fluid driven downstream from the chamber of the diaphragm pump to a section of the fluid conduit; and is

Controlling a speed of moving the peristaltic pump element to deliver the fluid from the positive displacement pump to the recipient at a desired flow rate.

17. The fluid delivery apparatus of claim 13, wherein the controller hardware is further operable to:

periodically receiving an amount of fluid into the chamber of the diaphragm pump from a fluid container at each of a plurality of fills, the fluid container being positioned differently relative to the chamber of the diaphragm pump.

18. The fluid delivery apparatus of claim 13, wherein the controller is further operable to:

measuring a flow rate of fluid driven downstream from the chamber of the diaphragm pump to the positive displacement pump, a mechanical pump element of the positive displacement pump blocking flow of fluid received from the diaphragm pump to the recipient; and is

Using the measured flow rate of the fluid, the delivery of fluid from the positive displacement pump to the recipient is controlled as specified by a flow rate setting.

19. The fluid delivery apparatus of claim 13, wherein the controller hardware is further operable to:

temporarily adjusting the application of pressure to the chamber to measure the rate at which the fluid is delivered downstream from the chamber to the positive displacement pump at each of a plurality of measured times between the first filling of the chamber and the subsequent time at which the fluid is drawn into the chamber from a fluid source.

20. The fluid delivery apparatus of claim 13, wherein the controller hardware is further operable to:

controlling a mechanical pump element of the positive displacement pump to provide a continuous flow of fluid from the positive displacement pump to the recipient in a time window; and is

Temporarily adjusting a magnitude of a pressure applied to the chamber of the diaphragm pump during each of a plurality of measurement windows occurring within the time window to measure a respective portion of fluid remaining in the diaphragm pump.

21. The fluid delivery apparatus of claim 20, wherein the controller hardware is further operable to release pressure applied to the chamber during a respective temporary adjustment of the measured fluid flow.

22. The fluid delivery apparatus of claim 21, wherein the controller hardware is further operable to: calculating a rate of fluid delivered by the positive displacement pump to the recipient using respective measured portions of fluid remaining in the diaphragm pump measured during the plurality of measurement windows.

23. The fluid delivery device of claim 22, wherein the positive displacement pump is a peristaltic fluid pump comprising corresponding peristaltic pump elements in physical contact with the elastically deformable section of fluid conduit, the pump elements restricting the flow of fluid received from the diaphragm pump through the elastically deformable section.

24. The fluid delivery apparatus of claim 13, wherein the controller hardware is further operable to:

drawing fluid received from the diaphragm pump from a fluid source into the chamber of the diaphragm pump during a condition in which the positive displacement pump blocks flow of the fluid to the recipient.

25. Computer readable storage hardware having stored thereon instructions that, when executed by computer processor hardware, cause the computer processor hardware to perform operations comprising:

drawing fluid into a chamber of a diaphragm pump;

applying pressure to the chamber of the diaphragm pump to output fluid in the chamber of the diaphragm pump downstream through the fluid conduit to a positive displacement pump; and is

Activating the positive displacement pump to pump the fluid from the positive displacement pump to a recipient during the applying the pressure to the chamber and outputting the fluid in the chamber downstream.

26. The method of claim 1, further comprising:

during the fluid measurement window:

halting movement of a pump element of the positive displacement pump; and

temporarily adjusting a pressure applied to the chamber of the diaphragm pump to measure a corresponding portion of fluid remaining in the diaphragm pump.

27. The fluid delivery apparatus of claim 13, wherein the controller hardware is further operable to:

stopping movement of a pump element of the positive displacement pump; and is

Temporarily adjusting a pressure applied to the chamber of the diaphragm pump while the pump element is stopped to measure a corresponding portion of fluid remaining in the diaphragm pump.

28. The method of claim 2, wherein a pressure of fluid in a first portion of the fluid conduit upstream of the positive displacement pump between the positive displacement pump and the diaphragm pump is less than a pressure of fluid in a second portion of the fluid conduit downstream of the positive displacement pump between the positive displacement pump and the recipient.

Background

Conventional techniques for delivering fluid to a recipient (e.g., a patient in a hospital or other patient care setting) using a diaphragm pump may include drawing fluid from a fluid source into a chamber of the diaphragm pump via application of negative pressure. After the chambers are filled, the respective fluid delivery systems apply positive pressure to the chambers, causing the fluid in the chambers to be delivered to the corresponding patients. The rate of delivery of the fluid to the recipient may vary depending on the magnitude of the positive pressure applied to the chamber. Eventually, after a sufficient amount of time to apply positive pressure to the chamber, the fluid in the chamber will be depleted and the chamber is refilled again using negative pressure.

In most applications, the amount of fluid drawn into the chamber of the diaphragm pump is substantially less than the total amount of fluid intended to be delivered to the patient. To deliver the appropriate amount of fluid to the patient over time, after emptying the previously filled chamber, the fluid delivery system repeats a cycle in which fluid is drawn into the chamber from the fluid source, and then positive pressure is applied to the chamber to deliver the fluid to the recipient.

According to conventional use of diaphragm pumps, the fluid delivery system is able to determine the rate at which fluid is delivered to a corresponding patient based on the amount of time that elapses between drawing fluid into a chamber in the diaphragm pump and completely expelling fluid out of the chamber in the diaphragm pump, operating in succession in time.

As previously mentioned, one type of fluid pump is a conventional diaphragm pump. Typically, during use, a negative pressure is applied to a conventional diaphragm pump to draw fluid into the respective fluid chamber. Thereafter, positive pressure is then applied to the conventional diaphragm pump to expel the fluid from the fluid chamber.

Another type of fluid pump is a conventional peristaltic pump. A peristaltic pump is a positive displacement pump used to pump various fluids. The fluid is contained within a flexible tube that fits within a circular pump housing (although linear peristaltic pumps have been made). A rotor having a plurality of "rollers", "shoes", "wipers" or "lobes" attached to the outer circumference of the rotor compresses the flexible tube. As the rotor rotates, a portion of the tube under compression is pinched closed (or "occluded") thereby pressurizing the fluid so that it is pumped to the recipient. Additionally, as the tube opens to its natural state ("recovery" or "resiliency") after the cam passes, fluid flow is directed to the pump.

Most currently available pumps used in healthcare such as infusion pumps and dialysis machines are open-loop positive displacement pumps. These conventional types of pumps are calibrated under fixed, known conditions. If the actual usage conditions are different from the calibration conditions, the actual fluid delivery rate may significantly deviate from the desired flow rate. Since fluid flow cannot be measured in such systems, the user cannot know if there is a problem with the fluid flow rate. The flow rate of these types of conventional pumps can be affected by inlet pressure (e.g., the height of the fluid source above the pump), outlet pressure or backpressure (e.g., downstream flow restriction of a smaller diameter conduit), fluid viscosity (e.g., concentrating human red blood cells 16 times the viscosity of saline). These and other environmental factors can severely affect the operation of positive displacement pumps.

Disclosure of Invention

A significant drawback of some conventional fluid pumps is that they are unable to monitor and/or measure the actual flow rate of the fluid being delivered to the patient.

One way to measure the flow rate of fluid to a recipient is to use a conventional flow rate sensor. The main difficulty in implementing flow rate sensors to measure flow is the very large required dynamic range required to accurately detect fluid delivery at different rates. For example, in some cases it is desirable for an intravenous syringe pump to operate at speeds ranging from as low as 0.1 ml/hour to as high as 1200 ml/hour or more. The dynamic range is at least 10000 to 1, which is far beyond the capabilities of most conventional sensors and measurement techniques.

Another requirement of conventional flow sensor technology for delivering fluids is that the delivered fluid must be contained entirely within a sterile disposable assembly. The fluid cannot directly contact the sensor or if the fluid does contact the sensor, the sensor must be thrown away after use due to contamination. Thus, it can be cost prohibitive to implement a disposable sensor capable of accurately measuring flow rate over a desired operating range.

Another limitation of conventional flow sensor technology is that intravenous fluids and medications constantly change and evolve over time. The user, and therefore the delivery system, does not know the unique fluid characteristics of the fluid being delivered. Therefore, flow measurement systems cannot be practically used or depend on the thermal, optical or density (viscosity) properties of the type of fluid to be dispensed.

Embodiments herein provide novel and improved fluid transport over conventional techniques.

More specifically, in accordance with one or more embodiments, a fluid delivery apparatus includes controller hardware, a pneumatically (gas) driven diaphragm pump, a downstream pump (e.g., a positive displacement pump), and a fluid conduit (a fluid tight passageway that carries fluid) that extends between the diaphragm pumps through the positive displacement pump to a recipient. The diaphragm pump may be configured to receive fluid from a remotely located fluid source. Accordingly, embodiments herein include pressure-controlled variable displacement pumps (e.g., diaphragm pumps) that feed variable positive displacement pumps (e.g., rotary peristaltic pumps, linear peristaltic pumps, rotary lobe pumps, progressive cavity pumps, rotary gear pumps, piston pumps, diaphragm pumps, screw pumps, gear pumps, hydraulic pumps, rotary vane pumps, etc.).

During the operation of delivering fluid to the recipient, the controller hardware first applies a negative pressure initially to draw fluid into the chamber of the diaphragm pump. After filling the chamber, the controller hardware applies positive pressure to the chamber of the diaphragm pump to output fluid in the chamber (of the diaphragm pump) downstream through the fluid conduit to the positive displacement pump. The positive displacement pump delivers fluid received from the diaphragm pump to a recipient.

According to still further embodiments, a pressure of fluid in a first portion of the fluid conduit upstream of the positive displacement pump (which clamps, occludes, controls, etc. the flow of fluid) and the diaphragm pump is greater than a pressure of fluid in a second portion of the fluid conduit downstream of the positive displacement pump.

According to some further embodiments, a pressure of fluid in a first portion of the fluid conduit upstream of the positive displacement pump (which clamps the flow of fluid) and the diaphragm pump is less than a pressure of fluid in a second portion of the fluid conduit downstream of the positive displacement pump.

According to another embodiment, the controller hardware of the fluid delivery apparatus as described herein is further operable to: the rate of fluid being driven downstream from a chamber of the diaphragm pump to the positive displacement pump is measured. In one embodiment, the controller hardware uses the measured rate of fluid being expelled from the chamber to control the rate at which fluid is delivered from the positive displacement pump to the recipient.

The flow rate of the fluid through the diaphragm pump may be measured in any suitable manner. For example, in one embodiment, the controller hardware is further operable to: on each of a plurality of cycles, a quantity (quantum) of fluid is periodically received (pumped) into the chamber of the diaphragm pump from a differently positioned fluid source container at each of the plurality of fills.

In one embodiment, the controller hardware applies negative pressure to a chamber of the diaphragm pump to draw fluid from the fluid source container. If desired, the controller hardware may be configured to draw fluid from the fluid source container into the chamber of the diaphragm pump during a condition in which the positive displacement pump blocks fluid received from the diaphragm pump from flowing through the positive displacement pump to the recipient. Thus, the diaphragm pump draws fluid from the upstream fluid source reservoir because the positive displacement pump blocks fluid flow, rather than drawing fluid in a direction from the positive displacement pump.

According to still other embodiments, gravity may be used as a means of filling the chamber of the diaphragm pump. For example, a container of fluid may be arranged above the membrane pump. Thus, negative pressure may not be required to draw fluid into the chamber.

As previously described, after drawing fluid into the chamber of the diaphragm pump, the controller hardware applies pressure to the chamber of the diaphragm pump to deliver fluid within the chamber downstream to the positive displacement pump.

In still other embodiments, to provide accurate fluid flow control over a wide range of possibilities, the controller hardware measures the flow rate of the fluid delivered to the recipient based on measurements of the remaining portion of the fluid in the chamber over time. For example, in one embodiment, the controller hardware is operable to measure the flow rate of fluid driven downstream from a chamber of the diaphragm pump to the positive displacement pump. As previously described, the positive displacement pump controllably blocks the flow of fluid received from the diaphragm pump to the recipient. The controller hardware utilizes the measured flow rate of the fluid (as detected from measuring the respective remaining portion of the fluid in the chamber of the diaphragm pump) to control the rate at which the fluid is delivered from the positive displacement pump to the recipient.

If the measured value of fluid flowing through the diaphragm pump is greater than the desired flow rate setting, the controller hardware reduces the rate at which fluid is delivered from the positive displacement pump to the recipient. Conversely, if the measured value of fluid flowing through the diaphragm pump as detected by the controller hardware is less than the desired flow rate setting, the controller hardware increases the rate at which fluid is delivered from the positive displacement pump to the recipient. Thus, in one embodiment, the measured fluid flow rate through the diaphragm pump may be used as a basis for controlling a downstream positive displacement pump to provide accurate fluid flow.

According to still further embodiments, at each of a plurality of measurement times between a first time to fill the chamber and a next successive time to fill fluid into the chamber from the fluid source, the controller hardware temporarily varies a magnitude of pressure to the chamber of the diaphragm pump at each of a plurality of sampling windows to measure a rate of delivery of fluid downstream from the chamber to the section. More specifically, according to one embodiment, the controller hardware also controls the positive displacement pump to provide a corresponding continuous flow of fluid from the positive displacement pump to the recipient in a time window in which the magnitude of the pressure in the diaphragm pump is temporarily modified to measure the delivery rate of the fluid delivered to the positive displacement pump. During each of a plurality of measurement windows in the time window, the controller hardware measures a respective portion of fluid remaining in the diaphragm pump to determine a respective fluid flow rate.

The controller hardware calculates the rate of fluid delivered by the positive displacement pump to the recipient using respective measured portions of fluid remaining in the diaphragm pump measured during the plurality of measurement windows. As previously discussed, in one embodiment, the positive displacement pump may be configured to include a corresponding mechanical pump element that controls the amount of fluid delivered by the positive displacement pump to the recipient.

Embodiments herein (e.g., a combination of a diaphragm pump for measuring fluid delivery rate and a positive displacement pump for controlling the physical delivery of fluid to a recipient) are superior to conventional techniques. For example, according to embodiments herein, a diaphragm pump is included: i) a way of measuring the flow rate of the fluid is provided, ii) a way of sucking the fluid from a source above or below the pump (using negative pressure) is provided, and iii) a constant and reliable pressure of the fluid to the inlet of the positive displacement pump is provided. The fluid delivery apparatus and corresponding methods as described herein also provide one or more of the following advantages over conventional techniques: i) fast start and stop times to achieve a desired delivery flow rate set point, ii) a large dynamic range to control the flow rate from 0.1 or lower to 1200 or higher, iii) flow rate control unaffected by inlet or outlet pressure changes, iv) flow rate control unaffected by fluid properties (e.g., viscosity), large changes in real-time flow measurements for improved safety, and the like.

These and other more specific embodiments are disclosed in more detail below.

It is noted that any resource as discussed herein may include one or more computerized devices, fluid delivery systems, servers, base stations, wireless communication equipment, communication management systems, workstations, handheld or laptop computers, or the like, to perform and/or support any or all of the method operations disclosed herein. In other words, one or more computerized devices or processors may be programmed and/or configured to operate as explained herein to perform the different embodiments of the invention.

Still other embodiments herein include software programs for performing the steps and operations summarized above and disclosed in detail below. One such embodiment includes a computer program product that includes a non-transitory computer-readable storage medium (i.e., any physical computer-readable hardware storage medium) on which software instructions are encoded for subsequent execution. When executed in a computerized device having a processor (e.g., computer processing hardware), the instructions program the processor and/or cause the processor to perform the operations disclosed herein. Such arrangements are typically provided as software, code, instructions and/or other data (e.g., data structures) arranged or encoded on a non-transitory computer readable storage medium such as an optical medium (e.g., CD-ROM), floppy disk, hard disk, memory stick, etc., or other medium such as firmware or short code in one or more ROMs, RAMs, PROMs, etc., or as an Application Specific Integrated Circuit (ASIC), etc. The software or firmware or other such configurations can be installed onto a computerized device to cause the computerized device to perform the techniques explained herein.

Accordingly, embodiments herein relate to methods, systems, computer program products, and the like, that support operations as discussed herein.

One embodiment herein includes a computer-readable storage medium and/or system having instructions stored thereon. The instructions, when executed by the computer processor hardware, cause the computer processor hardware to perform the following: drawing fluid into a chamber of a diaphragm pump; applying pressure to a chamber of the diaphragm pump to output fluid in the chamber of the diaphragm pump downstream through a fluid conduit to a positive displacement pump; and during application of pressure to the chamber and output of the fluid in the chamber downstream, activating the positive displacement pump to pump the fluid from the positive displacement pump to the recipient.

The order of the above operations has been added for clarity. It is noted that any of the process steps as discussed herein may be performed in any suitable order.

Other embodiments of the present disclosure include software programs and/or corresponding hardware to perform any of the operations outlined above and disclosed in detail below.

It should be understood that the systems, methods, devices, instructions on a computer-readable storage medium, etc., as discussed herein may also be embodied strictly as a software program, firmware, as a mixture of software, hardware, and/or firmware, or as hardware alone, such as within a processor or within an operating system or within a software application.

As discussed herein, the techniques herein are well suited for use in delivering fluids to any suitable target recipient. It should be noted, however, that the embodiments herein are not limited to use in such applications, and that the techniques discussed herein are well suited for other applications as well.

Additionally, it is noted that although each of the different features, techniques, configurations, etc. herein may be discussed in different places of this disclosure, it is intended that each concept may optionally be performed independently of each other or in combination with each other, where appropriate. Thus, the invention(s) as described herein may be embodied and viewed in many different ways.

Moreover, it is noted that the preliminary discussion of the embodiments herein purposefully does not specify each and every embodiment and/or added novel aspect of the disclosure or claimed invention. Rather, this brief description presents only general embodiments and corresponding novel points beyond conventional techniques. For additional details and/or possible perspectives (permutations) of one or more of the present invention, the reader will refer to the detailed description section and corresponding figures of the present disclosure as discussed further below.

Drawings

Fig. 1 is an example diagram illustrating a fluid delivery system according to embodiments herein.

Fig. 2 is an example diagram of an implementation of a diaphragm pump and a positive displacement pump to deliver fluid to a respective recipient according to embodiments herein.

Fig. 3 is an example diagram illustrating drawing fluid from respective fluid sources into a chamber of a diaphragm pump according to embodiments herein.

Fig. 4 is an example diagram illustrating the application of positive pressure to a chamber of a diaphragm pump to deliver fluid to a corresponding downstream positive displacement pump according to embodiments herein.

Fig. 5 is an example diagram illustrating movement of a mechanical pump element to deliver fluid (as received from a diaphragm pump) to a downstream recipient according to embodiments herein.

Fig. 6 is an example timing diagram illustrating timing windows associated with multiple pumping cycles and multiple measurement windows within each cycle, according to embodiments herein.

Fig. 7 is an example diagram illustrating control of a respective positive displacement pump based on a calculated fluid flow rate of fluid delivered by the respective diaphragm pump according to embodiments herein.

Fig. 8 is an example diagram illustrating a method of delivering fluid to a respective recipient using a combination of a diaphragm pump and a positive displacement pump according to embodiments herein.

Fig. 9 is an example graph illustrating changes in estimated gas temperature during a fluid measurement cycle, according to embodiments herein.

Fig. 10A is an example timing diagram illustrating applying different pressures to a diaphragm pump over time to deliver a fluid to a target recipient according to embodiments herein.

Fig. 10B is an example timing diagram illustrating applying different pressures to a diaphragm pump over time to deliver fluid to a target recipient according to embodiments herein.

Fig. 11 is an example timing diagram illustrating temporarily terminating or reducing the application of positive pressure to a diaphragm pump and estimating a gas temperature according to embodiments herein.

FIG. 12 is a diagram illustrating an example computer architecture in which any functionality is performed, according to embodiments herein.

Fig. 13-15 are exemplary diagrams illustrating methods of facilitating flow control measurement and management according to embodiments herein.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the embodiments, principles, concepts, etc.

Detailed Description

As previously described, in one embodiment, a fluid delivery apparatus includes controller hardware, a diaphragm pump, a positive displacement pump, and a fluid conduit extending between the diaphragm pump and the positive displacement pump. During operation and delivery of fluid to a downstream recipient, the controller hardware draws fluid into the chamber of the diaphragm pump. The controller hardware applies pressure to the chamber of the diaphragm pump to output fluid in the chamber of the diaphragm pump downstream through the fluid conduit to the positive displacement pump. During application of pressure to the chamber and output of fluid within the chamber downstream to the positive displacement pump, the controller hardware activates the positive displacement pump to pump fluid in the section from the positive displacement pump to a downstream recipient.

Now, more specifically, fig. 1 is an example diagram illustrating a fluid delivery system according to embodiments herein.

As shown, the fluid delivery environment 91 includes a fluid delivery system 100. The fluid delivery system 100 includes a fluid source 120-1, the fluid source 120-1 storing fluid for delivery to the recipient 108.

In one embodiment, the cartridge 104 is a disposable cartridge that is inserted into a chamber of a housing of a fluid delivery device 101 associated with the fluid delivery system 100. During delivery, fluid from fluid source 120-1 is restricted to contacting the disposable tubing set, which includes cassette 104, tubing 103, and their corresponding components, as discussed further below. When delivering fluid to a different patient, the caregiver inserts a new cartridge into the chamber of fluid delivery system 100. The new cassette comprises a corresponding set of new (sterile) tubes.

Thus, the fluid delivery system 100 can be used on many patients without the need for cleaning; a new cartridge is used for each fluid delivered.

As mentioned, during operation, the controller 140 of the fluid delivery system 100 controls the delivery of fluid from the source 120-1 to the recipient 108 (e.g., a patient or other suitable target). Tube 105-1 (fluid conduit) conveys fluid from fluid source 120-1 to cassette 104. Tubing 105-3 transports fluid from cassette 104 to recipient 108.

Controller 140 controls one or more components in cassette 104 to deliver fluid received from fluid source 120-1 to recipient 108 via tubing 105-3.

Fig. 2 is an example diagram of an implementation of a diaphragm pump and a positive displacement pump to deliver fluid to a respective recipient according to embodiments herein.

More specifically, according to one or more embodiments, a fluid delivery system (apparatus, device, etc.) includes a controller 140 (hardware and/or software), a diaphragm pump chamber 130, a positive displacement pump 184 (e.g., a rotary peristaltic pump, a linear peristaltic pump, a rotary lobe pump, a progressive cavity pump, a rotary gear pump, a piston pump, a diaphragm pump, a progressive cavity pump, a gear pump, a hydraulic pump, a rotary vane pump, a rope pump, a flexible vane pump, etc.), and a fluid conduit (fluid conduit) extending between the diaphragm pumps 130 to a recipient 108 through the positive displacement pump 184. During operation to deliver fluid to downstream recipient 108, controller 140 initially draws fluid into chamber 130-1 of diaphragm pump 130 (e.g., via a negative pressure of gas applied to chamber 130-2).

In one embodiment, the positive displacement pump is a non-pneumatically controlled pump (e.g., a rotary peristaltic fluid pump, a linear peristaltic pump, a rotary lobe pump, a progressive cavity pump, a rotary gear pump, a piston pump, a screw pump, a gear pump, a vane pump, a rope pump, a flexible vane pump, etc.). The diaphragm pump 130 is pneumatically (gas) driven and allows the controller to calculate the flow rate as described herein.

According to still other embodiments, positive displacement pump 184 may be another diaphragm pump (i.e., an air-operated pump). As described further herein, after filling chamber 130-1 with fluid from fluid source 120-1, controller 140 applies pressure (e.g., via positive gas pressure applied to chamber 130-2) to chamber 130-1 of diaphragm pump 130 to output fluid in chamber 130-1 (of diaphragm pump 130) downstream through a fluid conduit to positive displacement pump 184.

In one embodiment, positive displacement pump 184 is a peristaltic fluid pump. As shown, section 1110 of the fluid conduit of fluid delivery system 100 is an elastically deformable conduit (made of any suitable material such as rubber, plastic, etc.) driven by positive displacement pump 184. During application of positive (gas) pressure to chamber 130-1 (via filling chamber 130-2 with more and more gas over time) and output of fluid in chamber 130-1 downstream to positive displacement pump 184, controller 140 activates displacement pump 184 to pump fluid disposed in a portion of segment 1110 downstream of mechanical pump elements 186-1 (e.g., rollers, peristaltic pump elements, non-pneumatic pump elements, or other suitable elements to movably compress segment 1110 filled with fluid) along fluid conduits to downstream recipient 108.

Thus, in one embodiment, the diaphragm pump 130 delivers fluid to the elastically deformable conduit (section 1110); controller 140 controls positive displacement pump 184 and corresponding mechanical pump element 186-1 in a sweeping motion (in a downward direction in fig. 2) to deliver fluid in section 1110 in a downstream direction to recipient 108.

More specifically, as shown, in one embodiment, the mechanical pump element 186-1 contacts and pinches (and/or occludes) the elastically deformable conduit at position # 1. Via clamping, the mechanical pump element 186-1 blocks fluid flow from the diaphragm pump 130 further downstream of location #1 into a portion of the segment 1110 downstream of the mechanical pump element 186-1.

The sweeping physical contact of mechanical pump element 186-1 with the elastically deformable conduit controllably delivers fluid in the elastically deformable conduit further downstream to recipient 108. Thus, in one embodiment, the mechanical pump element 186-1 performs a number of operations including: i) restrict (or inhibit) fluid received upstream from mechanical pump element 186-1 from flowing from diaphragm pump 130 into section 1110 (the elastically deformable conduit), and ii) control, via positive displacement pump 184, fluid delivery in the section downstream from mechanical pump element 186-1 (the elastically deformable conduit) to recipient 108 (e.g., a human, an animal, a machine, etc.).

According to still other embodiments, the pressure of the fluid upstream of mechanical pump element 186-1 (pressure #1) is different than the pressure of the fluid downstream of mechanical pump element 186-1 (pressure # 2). More specifically, in one embodiment, during the pumping of fluid downstream from diaphragm pump 130 to positive displacement pump 184, the pressure #1 of fluid in a first portion of the fluid conduit upstream of mechanical pump element 186-1 (which blocks the flow of fluid via pinching/blocking the fluid conduit carrying the fluid) is greater than the pressure of fluid in a second portion of the fluid conduit downstream of mechanical pump element 186-1 (pressure # 2).

Conversely, in certain pumping situations, recipient 108 may exert a back pressure on the fluid being delivered through tube 105-3. In this case, the pressure #1 of the fluid in the respective portion of the fluid conduit upstream of the mechanical pump element 186-1 (which blocks the flow of fluid via pinching or blocking the fluid conduit carrying the fluid) is less than the pressure of the fluid in the second portion of the fluid conduit downstream of the mechanical pump element 186-1 (pressure # 2). For example, while positive displacement pump 184 is pumping fluid, recipient 108 may provide back pressure to receive fluid from a respective outlet of the fluid path through tube 105-3.

According to another embodiment, the controller 140 of the fluid delivery apparatus as described herein is further operable to: the rate of fluid being driven downstream from the chamber 130-1 of the diaphragm pump 130 to the section of fluid conduit is measured (in any suitable manner) using techniques as discussed in subsequent fig. 9-15 and text. In this case, controller 140 uses the measured rate of fluid displaced from chamber 130-1 over each of a plurality of measurement windows (shown in FIG. 10A as measurement D, measurement E, measurement F, measurement G, and measurement H). An example of a corresponding measurement window is shown in fig. 11 to control the rate at which the mechanical pump element 186-1 is moved to deliver fluid to a recipient at a desired flow rate. In such embodiments, diaphragm pump 130 serves as an accurate way of measuring the fluid delivered by positive displacement pump 184 to the respective recipient 108.

Note that the rates of operation of diaphragm pump 130 (pneumatic pump) and positive displacement pump 184 may be synchronized such that diaphragm pump 130 delivers fluid to section 1110 at a rate substantially similar to the rate at which fluid in section 1110 is delivered downstream to recipient 108 by positive displacement pump 184.

As discussed further below, it is noted that the fluid flow rate of the fluid through the diaphragm pump 130 can be measured using conventional algorithms known in the art based on the ideal gas law. For example, in one embodiment, the controller 140 is further operable to: at each of the plurality of fill cycles, a quantity of fluid is periodically received (pumped) into the chamber 130-1 of the diaphragm pump 130 from a differently positioned fluid source container (e.g., fluid source 120-1) at each of the plurality of fills. After each fill, controller 140 fills chamber 130-2 with a gas that applies a positive pressure to chamber 130-1, as previously described. As previously described, membrane 130-1 separates the fluid in chamber 130-1 from the gas in chamber 130-2.

In one embodiment, fluid delivery system 100 includes valve 125-2. The open/close setting of the valve 125-2 is controlled by the signal V9 generated by the controller 140. Note that valve 125-2 is optional. That is, at least one of mechanical pump elements 186 of positive displacement pump 184 may be configured to pinch or block section 1110 and prevent fluid flow through section 1110 at any or all times.

Fig. 3 is an example diagram illustrating drawing fluid from respective fluid sources into a chamber of a diaphragm pump according to embodiments herein.

As previously described, the controller 140 generates a corresponding control signal to control the state of the valve to either the open position or the closed position. In one embodiment, the controller 140 applies negative pressure (via the negative pressure tank 170-2) to the chamber 130-2 of the diaphragm pump 130 while the valve 125-3 (which in this embodiment is a controllable fully open or fully closed valve) is open, the valve 160-5 is open, the valve 160-1 is open, and the valves 160-4 and 160-3 are closed. This evacuates gas from chamber 130-2, causing membrane 127 to draw fluid from fluid source 120-1 (fluid container) into chamber 130-1 through valve 125-3.

If desired, controller 140 draws fluid from fluid source 120-1 into chamber 130-1 of diaphragm pump 130 in the event that mechanical pump element 186-1 of positive displacement pump 184 (or generally positive displacement pump 184 itself) blocks any downstream fluid being drawn back from flowing into chamber 130-1. In other words, mechanical pump element 186-1 of positive displacement pump 184 acts as a valve in the closed position, as shown in fig. 3. Thus, rather than drawing fluid further downstream from the elastically deformable conduit into chamber 130-1, the application of negative pressure to chamber 130-2 causes diaphragm pump 130 to draw fluid into chamber 130-1 only from upstream fluid source 120-1. As previously discussed, valve 125-2 in fig. 2 is optional.

Fig. 4 is an example diagram illustrating the application of positive pressure to a chamber of a diaphragm pump to deliver fluid to a corresponding downstream positive displacement pump according to embodiments herein.

As previously described, after drawing fluid into the chamber 130-1 of the diaphragm pump 130, the controller 140 closes the valve 125-3 and the valve 160-1 (via generation of the respective control signals V8 and V1); the controller 140 opens valves 160-5 and 160-4 (via generation of respective control signals V5 and V4) to apply positive gas pressure to chamber 130-2 of the diaphragm pump 130 to convey fluid in chamber 130-1 downstream to the positive displacement pump 184.

As shown, during the application of positive pressure to fluid in chamber 130-1, mechanical pump element 186-1 of positive displacement pump 184 controls the rate at which fluid from diaphragm pump 130 is allowed to flow downstream into section 1110. As previously described, in addition to controlling the amount of fluid received in the section 1110 upstream of the mechanical pump element 186-1, the motion of the mechanical pump element 186-1 (in the downstream direction) also controls the rate at which the respective fluid in the section 1110 is delivered to the recipient 108.

As previously discussed, it is noted that controller 140 may be configured to synchronously operate the fluid flow rate of the diaphragm pump and the fluid flow rate of positive displacement pump 184 such that diaphragm pump 130 delivers fluid to section 1110 at a rate substantially similar to the rate at which fluid in section 1110 is delivered downstream to recipient 108 by positive displacement pump 184.

Fig. 5 is an example diagram illustrating continuous motion of a mechanical pump element when receiving fluid from a diaphragm pump according to embodiments herein.

As shown, positive displacement pump 184 (e.g., a peristaltic fluid pump) may be configured to continuously rotate about a respective axis (the center of mechanical pump element 186) over time so that when mechanical pump element 186-1 reaches the end of segment 1110, the next mechanical pump element 186-2 contacts the beginning of segment 1110 to grip or block segment 1110. This establishes mechanical pump element 186-1 of positive displacement pump 184 as the starting position of section 1110. This begins a new cycle of sweeping the mechanical pump element 186-2 along the segment 1110 to deliver fluid to the respective recipient 108.

As previously described, in one embodiment, at least one of the mechanical pump elements 186 always clamps, occludes, compresses, blocks, etc. the section 1110 to prevent backflow of fluid from the section 1110 to the diaphragm pump 130. Thus, valve 125-2 may not be needed.

Note that positive displacement pump 184 can be any type of peristaltic mechanism (rotary, linear, piston, etc.) so long as downstream pump section 1110 is never allowed to open and allow free flow of fluid from diaphragm pump 130 to recipient 108. In other words, in one embodiment, the positive displacement pump or its corresponding elements (e.g., mechanical pump elements 186-1, 186-2, etc.) may be configured to always block the flow of fluid downstream from the diaphragm pump 130 to the recipient 108. In this case, positive displacement pump 184 continuously controls the flow of fluid to recipient 108.

Note that the ratio of the volume of fluid drawn into chamber 130-1 may be substantially the same as or different from the volume of fluid in section 1110.

Thus, in order to empty all the fluid stored in chamber 130-1, it may be necessary to: i) a single cycle of sweeping the mechanical pump element 186-1 along the section 1110, ii) less than a single cycle of sweeping the mechanical pump element 186-1 along the section 1110, or iii) multiple cycles of sweeping the mechanical pump element along the section 1110.

Additionally, if desired, it is noted that positive displacement pump 184 may operate in a continuous manner to provide a continuous flow of fluid to a respective recipient 108 even if controller 140 occasionally or periodically initiates a refill of chamber 130-1 during continuous flow and movement of mechanical pump element 186. Alternatively, if desired, controller 140 may be configured to interrupt operation of positive displacement pump 184 during conditions in which chamber 130-1 is being refilled with fluid from fluid source 120-1.

According to other embodiments, controller 140 may be configured to stop (halt) the movement of positive displacement pump 184 and the corresponding one or more pump elements (e.g., peristaltic pump elements) in contact with section 1110. When the pump element is stopped, the controller 140 temporarily adjusts the pressure applied to the chamber of the diaphragm pump to measure the corresponding portion of fluid remaining in the diaphragm pump in the manner previously discussed. Thus, if desired, embodiments herein may include pausing the positive displacement pumping mechanism to interrupt the flow of fluid from positive displacement pump 184 to recipient 108 during instances when the amount of fluid remaining in chamber 130-1 is being measured in the respective sampling window.

Fig. 6 is an example timing diagram illustrating multiple measurement windows per pump cycle according to embodiments herein.

According to embodiments herein, during FILL #1 at time T51, in the manner previously described, controller 140 applies negative pressure to chamber 130-2 and chamber 130-1 when valve 125-3 is open and when mechanical pump element 186-1 blocks fluid flow and prevents fluid in section 1110 from flowing back to chamber 130-1. During FILL #2, i.e., the next successive time to FILL chamber 130-1, controller 140 again applies negative pressure to chamber 130-2 when valve V8 is open and when mechanical pump element 186-1 prevents fluid in section 1110 from flowing back into chamber 130-1.

At each of a plurality of measurement times between the first FILL of FILL #1 and the next FILL of FILL #2, to measure the fluid in the chamber 130-1 of the diaphragm pump 130, the controller 140 temporarily adjusts the application to the chamber 130-2 and the magnitude of the positive pressure applied between the windows (fluid drive windows FDW1, FDW2, FDW3, FDW4, etc.) that occur between the two FILLs of FILL #1 and FILL # 2.

Discontinuing the application of pressure to chamber 130-2 (while closing valve 125-3 controlled by signal V8) may include temporarily varying the gas pressure from chamber 130-2 at each of a plurality of windows D1, E1, F1, G1, H1, etc., to measure the amount of fluid remaining in chamber 130-1 at respective times T61, T62, T63, T64, T65, etc.

Controller 140 uses the amount of fluid measured in chamber 130-1 at a plurality of sampling times to derive the rate at which fluid is delivered downstream from chamber 130-1 to segment 1110. For example, after FILL #1, the chamber may hold 0.5ml (milliliters) of fluid. Assume that measurements in window D1 around time T61 indicate 0.5ml in the chamber; measurements in window D2 around time T62 indicated 0.4ml in the chamber; measurements in window D3 around time T63 indicated 0.3ml in the chamber; measurements in window D4 around time T64 indicated 0.2ml in the chamber; and so on. If the measurement windows are spaced 4 seconds apart, the controller 140 determines that the flow rate through the diaphragm pump 184 is 0.3ml/12 seconds to 90 ml/hour.

According to a more specific embodiment, controller 140 further controls positive displacement pump 184 and mechanical pump element 186-1 in contact with section 1110 of the fluid conduit to continuously move along the length of section 1110 (e.g., even during FILL #, FILL #2, etc.) to provide a corresponding continuous flow of fluid from section 1110 to recipient 108 in the respective delivery windows.

As previously discussed, the controller 140 measures a respective portion of the fluid remaining in the diaphragm pump 130 during each of a plurality of measurement windows (D1, E1, F1, G1, H1 for cycle #1, and D2, E2, F2, G2, H2, etc. for cycle #2) that interrupt the application of pressure within the delivery window. Note again that details of the amount of fluid in the measurement chamber 130-1 are discussed above in FIG. 10A and elsewhere throughout the specification.

The controller 140 utilizes respective measured portions of the fluid remaining in the diaphragm pump 130 measured during a plurality of measurement windows (D1, E1, F1, G1, H1 for cycle #1 and D2, E2, F2, G2, H2, etc. for cycle #2) to calculate the rate of fluid delivered by the positive displacement pump 184 to the recipient 108. In the above example, the controller 140 determines that the rate of flow through the diaphragm pump 184 is 0.3ml/12 sec-90 ml/hr, as previously described. This indicates that the rate of fluid delivered by positive displacement pump 184 is 90 ml/hour. Accordingly, controller 140 utilizes respective measured portions of the fluid remaining in chamber 130-1 of diaphragm pump 130 measured during multiple measurement windows to calculate the rate of fluid delivered by positive displacement pump 184 to recipient 108.

As discussed further below, controller 140 may be configured to use the measured flow rate to control the operation of positive displacement pump 184 such that positive displacement pump 184 delivers fluid to the recipient at a desired rate. For example, as discussed further below, if the flow rate of the delivered fluid as indicated by the measurement of chamber 130-1 over time is less than the desired rate, controller 140 increases the rate at which fluid is delivered to the recipient by positive displacement pump 184. In one embodiment, the controller 140 increases the rate at which the mechanical pump element 186-1 is moved along the section 1110 to increase the rate of fluid flow to the recipient 108. Conversely, if the flow rate of the delivered fluid, as indicated by the measurement of chamber 130-1 over time, is greater than the desired rate, controller 140 decreases the rate at which fluid is delivered by positive displacement pump 184 to recipient 108. In one embodiment, the controller 140 decreases the rate at which the mechanical pump element 186-1 is moved along the section 1110 to decrease the rate of fluid flow to the recipient 108.

Fig. 7 is an example diagram illustrating control of a respective positive displacement pump based on a calculated fluid flow rate of fluid delivered by the respective diaphragm pump according to embodiments herein.

As previously described, to provide accurate fluid flow control over a wide range of possible flow rates, based on measurement windows D1, E1, F1, G1, H1 at multiple sample times (e.g., for cycle # 1); for cycle #2, a measurement of a respective remaining portion of fluid in chamber 130-1 over each of measurement windows D2, E2, F2, G2, H2, etc.), controller 140 measures the flow rate of fluid delivered to recipient 108.

In one embodiment, as shown, the controller 140 includes a diaphragm pump interface 1640. In the manner as previously discussed (e.g., using multiple measurement windows within a time window), the diaphragm pump interface 1640 is operable to measure the flow rate of fluid driven downstream from the chamber 130-1 of the diaphragm pump 130 out to the section 1110 of the fluid conduit. As mentioned, techniques for measuring flow rate are discussed in fig. 9-15. During operation, diaphragm pump interface 1640 generates signal 1630, which signal 1630 indicates the calculated fluid flow rate downstream from diaphragm pump 130 to positive displacement pump 184. The flow rate of fluid through the diaphragm pump 130 is typically (slightly variable over time) the same as the flow rate of fluid delivered downstream to recipient 108 by positive displacement pump 184.

According to still other embodiments, the controller 140 utilizes the measured flow rate of the fluid (as detected by measuring the respective remaining portion of the fluid in the chamber 130-1 of the diaphragm pump 130 over a plurality of sampling times T61, T62, T63, T64) to control (adjust) the sweep rate at which the mechanical pump element 186 is moved along the section 1110 of the fluid conduit to provide delivery of the fluid from the positive displacement pump (and the respective resiliently deformable conduit) to the recipient 108 as specified by a desired flow rate setting (e.g., a rate selected by a user).

For example, the difference logic 1620 generates a corresponding flow error signal 1660 that indicates the difference between the calculated fluid flow rate as indicated by signal 1630 (as measured from the diaphragm pump 130) and the target flow rate 1610.

If a measurement (as measured over time) of fluid flowing through diaphragm pump 130 is greater than a desired flow rate set point causing positive flow error signal 1660, positive displacement pump speed controller 1650 of controller 140 decreases the current rate of fluid delivery by positive displacement pump 184 by decreasing the rate at which mechanical pump element 186-1 is swept along section 1110. Conversely, if the measured value of fluid flowing through the diaphragm pump 130 as detected by the controller 140 is less than the desired flow rate set point causing a negative flow error signal 1660, the pump speed controller 1650 of the controller 140 increases the rate at which fluid is delivered to the recipient by the positive displacement pump 184 by increasing the rate at which the mechanical pump element 186-1 is swept.

As such, the controller 140 uses the flow error signal 1660 to control fluid flow to the target flow rate 1610. Thus, in one embodiment, the measured fluid flow rate through the diaphragm pump 130 may be used as a basis for controlling the downstream peristaltic pump 184 to provide very accurate fluid flow over a wide range.

As a further example, between time T61 and time T64, assume that the controller 140 is controlling the mechanical pump element 186-1 to move along the segment 1110 at a linear rate of 2.0 millimeters per second, which results in a flow rate of 90 milliliters per hour as described above. If the target flow rate is 108 milliliters per hour, then an error signal 1660 indicates 18 milliliters per hour. To deliver fluid at an appropriate rate of 108 milliliters per hour, the controller 140 will increase the rate at which the mechanical pump element 186-1 moves along the segment 1110 to a rate of 2.4 millimeters per second.

As previously discussed, the unique fluid delivery apparatus including the diaphragm pump 130 (to measure fluid delivery rate) and the positive displacement pump 184 (to control the physical pumping of fluid to recipient 108) provides advantageous fluid delivery compared to conventional techniques. For example, a fluid delivery apparatus and corresponding method as described herein provide one or more of the following advantages over conventional techniques: i) rapid start and stop times to achieve a desired delivery flow rate set point; ii) a large dynamic range to control flow rates from 0.1 milliliters or less per hour to 1200 milliliters or more per hour, iii) flow rate control unaffected by inlet or outlet pressure changes, iv) flow rate control unaffected by large changes in fluid properties (e.g., viscosity), and so forth.

Additionally, as discussed herein, applying positive pressure to the diaphragm pump feeds fluid to the positive displacement pump, resulting in better flow continuity. In addition, the diaphragm pump is operable to draw fluid using negative pressure. In this case, the diaphragm pump may suck the fluid from a container source arranged lower in height than the diaphragm pump.

Fig. 8 is an example diagram illustrating a method of delivering fluid to a respective recipient using a combination of a diaphragm pump and a positive displacement pump according to embodiments herein.

In a process operation 810 of the flowchart 800, the controller 140 (executing instructions of hardware and/or software) draws fluid from the fluid source 120-1 into the chamber 130-1 of the diaphragm pump 130.

In process operation 820, controller 140 applies pressure to chamber 130-1 of diaphragm pump 130 to output fluid in chamber 130-1 of diaphragm pump 130 downstream through the fluid conduit to positive displacement pump 184.

In processing operation 830, during the application of pressure to the fluid in chamber 130-1 and the output of the fluid downstream from the chamber to positive displacement pump 84, controller 140 activates the operation of positive displacement pump 184 to pump fluid from positive displacement pump 184 to recipient 108.

The control system comprises:

in one embodiment, using a known reference volume C1 (chamber 150), the ideal gas law can be used to measure the amount of unknown volume C2 (pump chamber 130-2):

PV＝nRT

wherein:

p is pressure

V is volume

n is the number of molecules

R is gas constant

T is temperature

Basic fluid flow measurements involve calculating the instantaneous volume of C2 at multiple points in time. The change in volume over time is the average flow rate over time:

wherein:

q ═ flow rate

t-time at which the corresponding volume measurement is carried out

C2 ═ volume of pump chamber 130-2

The volume measurement utilizes the known volume C1 (chamber 150) and isolation valve 160-5. The volume measurement cycle is as follows:

1. fluid valves 125-3 and 125-2 are (optionally) closed, stopping the flow of fluid into or out of the chamber and temporarily holding the volume of chamber 130-1 constant. As a result, the volume of air in the chamber 130-2(C2) is also constant during the measurement.

2. Air valve 160-5 is closed, isolating chamber 130-2(C2) from chamber 150 (C1).

In addition, valves 160-4 and 160-1 are also closed, further isolating the chambers.

3. The air valve 160-3 is opened to vent the chamber 150 to atmospheric pressure.

4. Air valve 160-3 is again closed, isolating chamber 150.

5. At this point in time, a pressure reading is recorded for sensor 135-5 (P2), and a pressure reading is recorded for sensor 135-3 (P1). These two pressure values are shown at time t1 on graph 610.

6. The next valve 160-5 is opened connecting chamber 130-2(C2) and chamber 150 (C1).

7. The combined pressure (Pmerge) is recorded by pressure sensors 135-5 and 135-3, as at the point in time shown at time t2 on graph 610. Since the chambers are now connected, the pressure measured by each of the sensors 135-5 and 135-3 is the same.

The pressure measurements recorded during this period are used to calculate the unknown volume of chamber 130-2(C2) in the following equation:

p1 — pressure of chamber 150(C2)

Pressure of chamber 130-2(C1) P2 ═ pressure

V1-volume of chamber 150(C2)

V2-volume of chamber 130-2(C1)

T1 ═ temperature of chamber 150(C2)

T2 ═ temperature of chamber 130-2(C1)

For chamber 150 (C2):

for chamber 130-2 (C1):

at time t1, when the chamber is isolated:

as previously described, the volume of chamber 130-2(C2), represented by V2, is unknown. To measure V2, the chambers are connected via valve 160-5 and gas molecules are transferred from one chamber to the other.

At time point t2 when the chambers are connected and the pressure is the same:

in this case, Pm is the combined pressure of the combined chambers, and the pressure readings of P1 and P2 are substantially equal. Due to the conservation of mass, and the total number of gas molecules in the two chambers does not change during this measurement period, the equation can be written as:

in this regard, the equation is typically simplified by utilizing Boyle's law and by assuming that the temperature of the system is constant during the measurement period. Under this assumption, the equation reduces to:

PmV1+PmV2＝P1V1+P2V2

solving for the unknown volume (V2) of chamber 130-2(C2), the equation can be rewritten as:

assuming that the system is at a constant temperature, the equation is greatly simplified, but as previously mentioned, system dynamics can result in transient temperature changes that can cause erroneous pressure readings, which can lead to volume calculation errors. The assumption of a constant temperature may not be appropriate if faster measurement speed or improved accuracy is required. The estimated temperature can be used to provide more accurate flow measurement readings, if desired, as discussed further below.

Due to the fact that gases have very low mass, it is difficult, if not impossible, to measure gas temperature quickly and accurately using readily available temperature sensor technologies such as thermocouples, RTDs, and the like. The only possible way to improve the accuracy of the volume calculation using temperature is to estimate the temperature change in the gas using knowledge of the system state and the dynamic changes caused by the manipulation of the control valves 160-1 to 160-5 and the fluid valves 125-3, 125-2.

Measurement algorithm for carrying out discontinuous fluid flow and/or estimated temperature for calculating fluid flow

By way of yet another non-limiting example embodiment, as an alternative to measuring the flow of fluid to recipient 108 using conventional techniques, it is noted that controller 140 may be configured to implement a mass fluid flow based measurement algorithm to account for the ideal gas law and conservation of mass. These equations remain for a closed system.

R is constant, so the equation factor drops to:

by taking into account the overall system state (e.g., temperature), rather than assuming that the system state remains constant over a period, the estimation of temperature as disclosed herein enables rapid fluid flow measurements and allows the fluid delivery system 100 (devices, hardware, etc.) and the controller 140 to operate without stopping fluid flow during the fluid flow measurements.

More specifically, in one embodiment, an appropriate driving pressure may be applied to the driving chamber side of the diaphragm pump 130 (e.g., chamber 130-2) to deliver the fluid in the fluid chamber side of the diaphragm pump 130 (chamber 130-1) to the target recipient 108. Other embodiments herein may include temporarily modifying the magnitude of the gas pressure applied to the chamber 130-2 one or more times during the delivery cycle to perform a volume check to identify how much fluid is present in the fluid chamber 130-1 of the diaphragm pump 130 over time.

In one embodiment, the flow rate of the fluid pumped to the target recipient is equal to the change in volume of the fluid in chamber 130-2 of the diaphragm pump 130 over time.

During the time that pressure is applied to chamber 130-2 is modified, embodiments herein may include accounting for estimated changes in gas temperature due to adiabatic heating and cooling due to rapid pressure changes in one or more chambers when calculating the flow rate of fluid downstream through chamber 130 to positive displacement pump 184.

In one embodiment, the mass balance measurement is dependent on the temperature of the working fluid. In view of the above-mentioned required measurement speed, the gas undergoes adiabatic heating and cooling during the measurement period. It is impractical (if not impossible) to measure the gas temperature directly (with a temperature sensor) within the desired time frame. Therefore, the heat estimator is used to predict the gas temperature. In other words, the temperature of the gas in one or more volumes as discussed herein may change so rapidly that the physical temperature sensor cannot detect a corresponding change in temperature.

Fig. 9 is an example graph illustrating gas temperatures in different resources during a delivery cycle according to embodiments herein. As described herein, one or more temperatures may be estimated based on known system information, as discussed in more detail below.

Another requirement of the infusion system may be to maintain a continuous flow. In one embodiment, a fluid delivery system as discussed herein does not stop pumping (e.g., pumping fluid via positive displacement pump 184) during flow rate measurements. Thus, embodiments herein may include providing a continuous or substantially continuous flow of fluid delivered to a respective target recipient.

In order not to introduce measurement errors, the volume measurement cycle can be performed extremely fast, for example in the order of milliseconds. According to embodiments herein, the measurement period may be less than 200 milliseconds. A filling cycle, such as filling a chamber of a diaphragm pump with fluid, may also be performed very quickly to minimize flow variations.

When the gas is moving at this higher velocity for all of the reasons described above, the isothermal assumption is generally used to simplify the ideal gas law, and Boyle's law becomes ineffective.

In particular, the assumption that the gas is at a constant temperature during the measurement period is no longer true.

It was observed that the gas underwent adiabatic heating and cooling during the measurement period. As previously discussed, embodiments herein include estimating gas temperature to compensate for these errors.

To address the temperature effects due to adiabatic heating and cooling of the gas, the pressure and volume relationship yields:

as a non-limiting example, the temperature may be estimated by tracking system state variables at each time step of the control loop. The physical parameters of the delivery system, such as volume, fluid conduit size (where the fluid is air), and heat transfer coefficient in combination with the measured pressure, allow the system to calculate an estimated temperature in each of the gas volumes at any point during the pumping cycle using the following energy balance equation:

wherein:

v is volume

Cv-specific heat at constant volume

Cp is constant specific pressure heat

T is temperature

Q-mass flow

H-heat transfer coefficient