阅读说明：本技术 控制可用计量泵输送的液量的方法 (Method for controlling the amount of liquid that can be delivered by a metering pump ) 是由 M·莱因哈德 于 2021-06-15 设计创作，主要内容包括：本发明涉及一种控制可在给定时间内用计量泵输送的液体量的方法,该方法包括以下步骤：a.提供用于控制可在给定时间内用计量泵输送的液体量的输入信号,以及b.将该输入信号与影响可在给定时间内用计量泵输送的液体量的致动信号建立联系以使得输入信号的改变导致致动信号的改变并因而导致可输送的液体量的改变。为了对个体过程要求有所响应,根据本发明提出了步骤b中的建立联系是按以下方式来实现的：使得输入信号的改变导致可在给定时间内用计量泵输送的液体量的改变,液体量的这种改变与输入信号的改变是非比例的。(The invention relates to a method for controlling the amount of liquid that can be delivered by a metering pump at a given time, comprising the following steps: a. providing an input signal for controlling the amount of liquid that can be delivered with the metering pump in a given time, and b. relating this input signal to an actuation signal that influences the amount of liquid that can be delivered with the metering pump in a given time, such that a change in the input signal results in a change in the actuation signal and thus in a change in the amount of liquid that can be delivered. In order to respond to individual process requirements, it is proposed according to the invention that the establishing of the contact in step b is carried out in the following way: such that a change in the input signal results in a change in the amount of liquid that can be delivered by the metering pump in a given time, which change in the amount of liquid is not proportional to the change in the input signal.)

1. A method of controlling the amount of liquid that can be delivered with a metering pump (10) in a given time, the method comprising the steps of:

a. providing an input signal (1) for controlling the amount of liquid that can be delivered in a given time by a metering pump (10), and

b. correlating the input signal (1) with an actuation signal (2), the actuation signal (2) influencing the amount of liquid that can be delivered with the metering pump (10) in a given time, such that a change in the input signal (1) leads to a change in the actuation signal (2) and thus to a change in the amount of liquid that can be delivered with the metering pump (10) in a given time,

c. the establishing of the contact in the step b is realized according to the following modes: such that a change in the input signal (1) results in a change in the amount of liquid that can be delivered by the metering pump (1) in a given time, which change in the amount of liquid is non-proportional to the change in the input signal (1).

2. Method according to the preceding claim, characterized in that the establishment of the association in step b is carried out as follows: such that a change of the input signal (1) results in a change of the amount of liquid that can be delivered with the metering pump (1) in a given time, said change of the amount of liquid being non-linear with respect to the change of the input signal (1).

3. Method according to one of the preceding claims, wherein the linking of the input signal (1) to the actuation signal (2) is realized by a mathematical function, wherein the mathematical function is non-proportional, preferably a non-linear function.

4. Method according to the preceding claim, wherein said mathematical function is a strictly monotonically increasing or strictly monotonically decreasing function.

5. Method according to one of the preceding claims, wherein the mathematical function is a polynomial, preferably a quadratic polynomial and particularly preferably a cubic polynomial.

6. Method according to one of the preceding claims, wherein the input signal (1) is an analog signal, preferably a voltage, wherein in an additional step the analog input signal (1) is converted into a digital intermediate signal (3), wherein in step b the digital intermediate signal (3) is linked to the actuation signal (2).

7. Method according to one of the preceding claims, wherein in step b, establishing a contact is carried out in the following way: the linearly increasing input signal firstly leads to an increase in the amount of liquid that can be delivered by the metering pump (10) in a given time and subsequently to a decrease in the amount of liquid that can be delivered by the metering pump (10) in a given time.

8. A metering pump (10) for delivering an amount of liquid at a given time, comprising:

a metering chamber (11),

a displacement element (12) movable between a first position and a second position, wherein the displacement element (12) is connected to the metering chamber (11) such that a metering chamber volume of the metering chamber (11) varies as the displacement element (12) moves between the first position and the second position,

a drive (13) for moving the displacement element (12) between the first position and the second position, and

a control (14), wherein the control (14) is connected to the drive (13) such that during operation of the metering pump (10) the drive (13) is controlled by the control (14) by means of the actuation signal (2) such that the amount of liquid of the liquid delivered by the metering pump (10) within the given time varies as a result of a change in the actuation signal (2), wherein the control (14) further has an input for an input signal (1), wherein the input signal (1) at the input is linked in the control (14) to the actuation signal (2) such that a change in the input signal (1) leads to a change in the actuation signal (2), characterized in that the input signal (1) is linked in the control (14) to the actuation signal (2) such that a change in the input signal (1) leads to a change in the given time by the metering pump (10), wherein the control (14) is connected to the input signal (1) such that a change in the input signal (1) leads to a change in the actuation signal (2) leads to a change in the given time by the metering pump (10) A change in the amount of liquid delivered, the change in the amount of liquid being non-proportional to a change in the input signal.

9. The metering pump (10) according to claim 8, wherein the actuation signal influences the stroke frequency, the stroke length and/or the stroke speed of the displacement element (12) of the metering pump (10).

10. Metering pump (10) according to one of claims 8 and 9, wherein the input signal (1) is a digital input signal (1) or is converted into a digital intermediate signal (3) by means of an analog-to-digital converter (15), wherein the actuation signal (2) is an analog signal, wherein the control (14) of the metering pump (10) further has a digital-to-analog converter (16), wherein the digital input signal (1) or the digital intermediate signal (3) is converted into an analog actuation signal (2) in the control (14) by means of the digital-to-analog converter (16), wherein the digital-to-analog converter (16) is a non-proportional digital-to-analog converter (16).

Technical Field

The invention relates to a method of controlling the amount of liquid that can be delivered by a metering pump in a given time, the method comprising the steps of:

a. providing an input signal for controlling the amount of liquid that can be delivered by the metering pump in a given time, an

b. The input signal is linked to an actuation signal which influences the amount of liquid which can be delivered with the metering pump in a given time, so that a change in the input signal leads to a change in the actuation signal and thus to a change in the amount of liquid which can be delivered with the metering pump in a given time.

Furthermore, the invention relates to a metering pump for delivering an amount of liquid of a liquid in a given time, the metering pump comprising: a metering chamber; a displacement element movable between a first position and a second position, wherein the displacement element is connected to the metering chamber such that a metering chamber volume of the metering chamber varies as the displacement element moves between the first position and the second position; a driver for moving the displacement element between the first position and the second position; and a control, wherein the control is connected to the drive such that during operation of the metering pump the drive is controlled by the control by means of the actuation signal such that the amount of liquid delivered by the metering pump in a given time varies as a result of a change in the actuation signal, wherein the control further has an input for an input signal, wherein the input signal at the input is linked in the control to the actuation signal such that a change in the input signal is linked to a change in the actuation signal.

Background

Metering pumps are used in a very wide variety of different fields of application. They are used, for example, in the metering of medicaments or chemicals in chemical processes, in the metering of culture media in biotechnological processes, in coating processes, in the food industry or as, for example, infusion pumps in motor vehicles. The possible uses of metering pumps are diverse and, as a result, the industry has a wide variety of demands for metering pumps.

In principle, a metering pump is a displacement pump which delivers an amount of liquid defined per revolution, per stroke or per time, irrespective of the pressure conditions at its inlet and outlet. In the example of a metering pump, the metering operation is achieved by displacing the closed chamber volume by means of a displacement element. The amount of liquid delivered by the metering pump per revolution, stroke or stroke results from the product of the stroke and the effective area of the displacement element.

In this example, the amount of liquid delivered by the metering pump in a given time may be influenced on the one hand by, for example, the size of the metering chamber of the metering pump, or on the other hand by the stroke frequency or stroke speed of the metering pump.

In metering pumps, the usually continuous rotational movement of the drive is frequently converted by the transmission unit into an oscillating movement of the displacement element. Accordingly, the stroke frequency of the metering pump and consequently the amount of liquid that can be delivered by the metering pump can be varied by appropriate actuation of the drive.

In this connection, it is known from the prior art to provide an input signal which is converted into an actuation signal for driving by a control system of the metering pump in order to control the metering pump. In this case, the conversion of the input signal is effected in such a way that the change in the amount of liquid that can be delivered by the metering pump is proportional to the change in the input signal. Thus, depending on the input signal applied accordingly, more or less liquid is delivered by the metering pump.

In addition, it is known that any non-proportionality between the change in the amount of liquid that can be delivered by the metering pump and the input signal (for example, due to environmental influences or wear of the components of the metering pump) is compensated by a suitable control system in such a way that the proportionality between the specified variables is restored. In this case, it may be necessary to create a non-proportional relationship between the input signal and the actuation signal, such that the input signal and the amount of liquid delivered in a given time are again proportional to each other. However, a change of the input signal to a given extent always results in the same degree of change of the amount of liquid that can be delivered in a given time.

However, as mentioned in the introductory part of the present description, it is often desirable that the amount of liquid that can be delivered with a metering pump is more individually adapted to the respective requirements of the process depending on the time. Thus, for example, in the region of the quantity of liquid that can be optimally delivered for a process each time, a particularly small step adjustment of the quantity of liquid that can be delivered is often required, while in other regions, the change can be effected in coarse steps. However, this is not possible in the case of a proportional relationship between the input signal and the amount of liquid that can be delivered in a given time.

Disclosure of Invention

Starting from the described prior art, it is an object of the present invention to provide a method for controlling the amount of liquid that can be delivered with a metering pump in a given time, whereby individual process complaints can be responded to. In addition, it is an object of the invention to provide a metering pump, the amount of liquid which can be delivered in a given time being individually adaptable to the process requirements.

This object is achieved by a method of controlling the amount of liquid that can be delivered by a metering pump at a given time, the method comprising the steps of:

a. providing an input signal for controlling the amount of liquid that can be delivered by the metering pump in a given time, an

b. Correlating the input signal with an actuation signal that affects the amount of liquid that can be delivered with the metering pump in a given time, such that a change in the input signal results in a change in the actuation signal and thus in a change in the amount of liquid that can be delivered with the metering pump in a given time,

wherein the establishing of the contact in the step b is realized by the following steps: such that a change in the input signal results in a change in the amount of liquid that can be delivered by the metering pump in a given time, which change in the amount of liquid is not proportional to the change in the input signal.

The input signal may be a digital signal or an analog signal which is often provided by the user side of the metering pump. Inexpensive electronic components that permit changes in the input signal may be used to generate such input signals. In this regard, a range of values within which the value of the input signal is movable is predetermined for the input signal. For example, the method may be provided for input voltage signals between 0V and 15V.

According to the invention, establishing a non-proportional relationship between the input signal and the actuation signal has the result that: the amount of liquid delivered by the metering pump at a given time may vary non-proportionally to the input signal. Accordingly, the method according to the invention differs from the prior art in that there is no proportional relationship between the input signal and the amount of liquid that can be delivered with the metering pump in a given time.

According to the invention, the term proportional relationship is used to mean that the input signal and the amount of liquid that can be delivered with the metering pump in a given time are always in the same relationship with each other, i.e. one variable is converted into another variable by multiplication with a constant proportional factor. Thus, if a non-proportional relationship is mentioned according to the invention, this means a relationship in which two specified variables cannot be converted into each other by multiplication with a constant scale factor. Mathematically, this relationship can be expressed as:

y(x)＝m(x)^a+c(x)

where y is the amount of liquid that can be delivered, x is the input signal, and m is a constant scale factor. c (x) is a variable that depends on the input signal and can take any function. In the simplest case, c (x) is 0. In addition, according to the present invention, only those relationships where α ≠ 1 are considered to be non-proportional.

The method according to the invention therefore aims to produce a deliberate non-proportionality between the input signal and the quantity of liquid that can be delivered. The non-proportionality between the input signal and the actuation signal therefore has the purpose not to compensate for any deviations from the establishment of a proportional link, for example due to environmental influences or wear, as in the prior art, which ultimately again leads to a proportional relationship between the input signal and the amount of liquid that can be delivered; instead, a non-proportional relationship between the input signal and the actuation signal is achieved such that the input signal and the liquid that can be delivered likewise establish a non-proportional relationship with each other.

Thus, the method according to the invention provides the advantage that: the input signals present, for example, on the user side of the metering pump are individually adapted to the respective process requirements. In addition to the same input signal, different delivery rates can also be achieved on the metering pump side depending on the respective design configuration of the control.

It is thus possible that more liquid is introduced into the mixture at the beginning of the process than towards the end of the process, at which the proportion of liquid is set as precisely as possible. The method according to the invention provides the advantage here that, for example, at the start of the process, the input signal leads to a rapid change in the amount of liquid that can be delivered, while a finer adaptation of the change in the amount of liquid on the basis of the input signal is possible towards the end of the process or shortly before each approach to the optimum amount of liquid. Thus, on the one hand this allows saving time at the start of the process, while on the other hand it provides a more accurate setting of the required liquid supply, which ultimately results in a higher quality of the manufactured product.

In a further embodiment, the establishing of the contact in step b is implemented as follows: such that a change in the input signal results in a change in the amount of liquid that can be delivered with the metering pump in a given time, said change in the amount of liquid being non-linear with respect to the change in the input signal. In this case, that is to say, even the relation between the input signal and the actuating signal or the quantity of liquid that can be delivered according to the following is excluded,

y(x)＝mx+b

where b is the shift constant of the linear function.

Correlating the input signal to the actuation signal can be accomplished in a variety of ways. In an embodiment, the data set in which the value of the actuation signal has been previously assigned to each input signal is set up for linking the input signal with the actuation signal. This provides the advantage of saving computational power in the control system, while the control of the metering pump can be adapted very individually to the process requirements. The set-up data set is particularly suitable for smaller control ranges which contain only a limited number of values and in such ranges it is known exactly what value of the input signal will be associated with what amount of liquid that can be delivered in a given time.

In a further embodiment of the invention, the correlation of the input signal with the actuation signal is realized by a mathematical function, wherein the mathematical function is non-proportional, preferably non-linear. A mathematical function has the advantage that it is possible to automatically associate each value of the input signal with a corresponding value of the actuation signal. Thus, even values of the actuation signal which have not previously been established, for example manually, can be correlated with values of the input signal.

In a further embodiment of the method according to the invention the mathematical function is a strictly monotonically increasing function or a strictly monotonically decreasing function. This ensures that each input value has an actuation value which differs from the adjacent actuation value, so that a change in the input signal always results in a change in the amount of liquid which can be delivered by the metering pump in a given time.

In a further embodiment, the mathematical function is a polynomial, preferably a quadratic polynomial and particularly preferably a cubic polynomial. The polynomials can be adapted to almost any functional implementation depending on their power. Thus, the use of a polynomial has the following advantages: a particularly individual control profile of the amount of liquid can be generated without the need for earlier manual correlation of the value of the input signal with the value of the actuation signal in the stored data set.

In a further embodiment, the input signal is an analog signal, preferably a voltage signal, wherein in an additional step the analog input signal is converted into a digital intermediate signal, wherein in step b the digital intermediate signal is linked to the actuation signal. Thus, the digital intermediate signal is linked to both the input signal and the actuation signal. The digital signal can be more easily and also more accurately linked to the actuation signal in the control system.

In a further embodiment the digital intermediate signal preferably has 25 steps. In terms of computational engineering, the number of steps still needs to be managed in a short time, but at the same time provides a good enough resolution to adequately represent changes in the input signal.

In a further embodiment of the method according to the invention, in step b, establishing contact is carried out in the following manner: a linearly increasing input signal firstly leads to an increase in the amount of liquid that can be delivered by the metering pump in a given time and subsequently to a decrease in the amount of liquid that can be delivered by the metering pump in a given time.

In other words, for example, a linear increase in the input signal may first result in an increase in conveyor speed and then a decrease. In this case, the increasing gradient may be less than or greater than the magnitude of the decreasing gradient.

Example 1:

bandwidth of input signal: 0-100V

Bandwidth of conveyor speed: 0-10l/s

Input signal interval 1: conveyor speed interval 1 of 0-20V: 0-10l/s

Input signal interval 2: conveyor speed interval 2 of 20V-100V: 10-8l/s

In case the input signal is between 0 and 20V, the pump can be actuated between a conveyor speed of 0 and 10 l/s. A voltage change of 0.5V subsequently results in a change of the conveyor speed of 0.25 l/s. Accurate metering is thus difficult.

In the input signal interval 2, a further conveyor speed interval is available. The pump can be actuated between 10 and 8l/s conveyor speed when the input signal is between 20 and 100V, wherein the conveyor speed reaches 8l/s when the voltage is 100V. In the input signal interval, a voltage change of 0.5V results in a change of the conveyor speed of 0.0125 l/s. Accurate metering is thus much easier.

This property of establishing a link is significant if conveyor speeds between 8 and 10l/s are generally required.

In a preferred embodiment, the mathematical function is selected based on an expected conveyor speed.

The object of the invention is also achieved by a metering pump for delivering an amount of liquid in a given time, wherein the metering pump has a metering chamber, a displacement element which is movable between a first position and a second position, a driver for moving the displacement element between the first position and the second position, wherein the displacement element is connected to the metering chamber such that a metering chamber volume of the metering chamber changes as the displacement element moves between the first position and the second position, and a control, wherein the control is connected to the driver such that during operation of the metering pump the driver is controlled by the control by means of an actuation signal such that the amount of liquid delivered by the metering pump in the given time changes as a result of a change in the actuation signal, wherein the control further has an input for an input signal, wherein the input signal at the input is linked in the control to the actuation signal, such that a change in the input signal causes a change in the actuation signal, wherein the input signal is linked to the actuation signal in the control such that a change in the input signal causes a change in the amount of liquid delivered by the metering pump in a given time, said change in the amount of liquid being non-proportional to the change in the input signal.

If the method is carried out with a metering pump according to the invention, it has suitable equipment for this purpose. In a particular embodiment, the metering pump is adapted to perform the above-described embodiment of the method.

Thus, according to the invention, it is provided that the input signal is provided by an external source. An actuation signal is then generated dependent on the input signal.

In an embodiment, the actuation signal affects a stroke frequency, a stroke length, and/or a stroke speed of a displacement element of the metering pump. These three variables of the metering pump have a significant effect on the amount of liquid that can be delivered by the metering pump in a given time.

In a further embodiment, the input signal is a digital input signal or the input signal is converted into a digital intermediate signal by means of an analog-to-digital converter. In addition, the actuation signal in this embodiment is an analog signal, wherein the control system of the metering pump further has a digital-to-analog converter, wherein the digital input signal or the digital intermediate signal is converted into the analog actuation signal in the control system by means of the digital-to-analog converter, wherein the digital-to-analog converter is a non-proportional digital-to-analog converter.

Typically, an analog-to-digital converter or a digital-to-analog converter results in a proportional conversion between the input signal and the output signal. Accordingly, according to the present invention, the scaling represents a conversion of always converting the value of the input signal into the value of the output signal by a constant scaling factor. Even if, for example, the analog-to-digital converter reduces the value of the input signal to several values of the output signal, those values of the output signal can always be set relative to the value of the input signal by a constant ratio value.

Thus, the term non-proportional digital-to-analog converter is used according to the invention to denote a digital-to-analog converter that converts input values of a signal such that they can no longer be related together by a common constant scaling factor.

Drawings

Further advantages, features and possible uses of the invention will become apparent from the following description of embodiments and the accompanying drawings. In this case, the same components are denoted by the same reference numerals.

Figure 1 shows a schematic view of an embodiment of a metering pump according to the invention,

figure 2a schematically shows a digital intermediate signal depending on an input signal,

figure 2b schematically shows an actuation signal dependent on a digital intermediate signal in a first embodiment of the method according to the invention,

fig. 2c schematically shows an actuation signal dependent on a digital intermediate signal in a second embodiment of the method according to the invention, an

Fig. 2d schematically shows an actuation signal dependent on a digital intermediate signal in a third embodiment of the method according to the invention.

Detailed Description

Fig. 1 shows an embodiment of a metering pump 10 according to the invention, which metering pump 10 has a metering chamber 11 and a displacement element 12 which is movable between a first position and a second position, wherein the displacement element 12 is reciprocated between the first position and the second position by an actuator 13. In addition, the metering pump 10 according to the invention has a control 14, which control 14 is connected to the drive 13 such that the actuating signal 2 is transmitted from the control 14 to the drive 13. The controller 14 thus controls the driver 13 by means of the actuation signal 2.

Liquid is drawn into or pushed out of the stroke chamber 11 by the movement of the displacement element 12. In this case, the control 14 acts on the stroke frequency of the displacement element 12 and the metering chamber volume of the metering pump 10 by means of the actuation signal 2 and the drive 13. In this manner, the amount of liquid that can be delivered by the metering pump 10 at a given time can be varied.

The change of the quantity of liquid that can be delivered with the metering pump 10 in a given time is effected by means of an analog input signal 1, for example a voltage signal, which is converted in a first step into a digital intermediate signal 3 by means of an analog-to-digital converter 15. The digital intermediate signal may for example take up to 25 discrete values. The digital intermediate signal 3 is passed to a control 14, which control 14 in turn has a digital-to-analog converter 16 for converting the digital intermediate signal 3 into an analog actuation signal 2, so that a change in the input signal 1 or the digital intermediate signal 3 leads to a non-proportional change in the actuation signal 2 and thus to a non-proportional change in the amount of liquid that can be delivered with the metering pump 10 in a given time.

Fig. 2a shows the result of the analog-to-digital conversion by means of the analog-to-digital converter 15. It can be seen that the analog-to-digital converter 15 converts the incoming input signal 1 proportionally into the digital intermediate signal 3, i.e. the value of the input signal 1 is linked to the value of the digital intermediate signal 3 by a scaling factor.

Subsequently, fig. 2b shows the result of a first embodiment of the digital-to-analog converter 16, which digital-to-analog converter 16 relates the digital intermediate signal 3 to the actuation signal 2 by means of a non-proportional mathematical function. As shown in fig. 2, the mathematical function is of the form y-x²A square function of (d). A change of the digital intermediate signal 3 or of the input signal 1 at a lower value here leads to a relatively slight change of the actuation signal 3 and thus to a relatively slight change of the amount of liquid that can be delivered with the metering pump 10 in a given time. In contrast, a change of the digital input signal 3 at a higher value results in a more significant change of the actuation signal 2. In this embodiment, for example at the beginning of the process, initially little liquid can be supplied in a very targeted manner and later more when a less precise setting of the liquid supply is sufficient.

In fig. 2c, the digital intermediate signal 3 is linked to the actuation signal 2 by a root-form function in the digital-to-analog converter 16. Although a considerable change of the actuation signal 2 and thus of the amount of liquid that can be delivered with the metering pump 10 in a given time is achieved at a lower value of the digital intermediate signal, a change of the digital intermediate signal 3 at a higher value results in a smaller change of the actuation signal. Thus, in this embodiment of fig. 2c, it is possible to quickly reach the required amount of liquid which can then be adjusted in fine steps.

Fig. 2d shows the output of another embodiment of the digital-to-analog converter 16. It can be seen that there is a first sub-interval 17 in the digital intermediate signal, wherein a change in the digital intermediate signal 3 results in no or almost no change in the actuation signal 2. In a second subinterval 18 of the digital intermediate signal 3, the actuation signal crosses a minimum value.

In the case of an input signal 1 or a digital intermediate signal 3 thus linked to the actuating signal 2, a local maximum is therefore taken in the first subinterval 17 and a local minimum in the second subinterval 18. These local minima and maxima can be individually adapted to the process requirements.

The conveyor speed can be set very accurately within the desired range by means of an easily generated analogue input signal, compared to known systems in the prior art. The user of the pump does not have to make any high level requirements on the reliability and accuracy of the input signal.

List of reference numerals

1 input signal

2 actuating signal

3 intermediate signal

10 metering pump

11 measuring chamber

12 displacement element

13 driver

14 control

15 analog-to-digital converter

16D/A converter

17 first subinterval

18 second sub-interval