阅读说明：本技术 气动计量泵及其测量方法 (Pneumatic metering pump and measuring method thereof ) 是由 张维国 于 2019-03-19 设计创作，主要内容包括：本发明公开了一种气动计量泵,包括泵体,泵体内部设有计量腔室和检测腔室,计量腔室的上端设有进出气口,下端进液口和出液口上分别安装有进液单向阀及出液单向阀,计量腔室内部设有液位浮子,液位浮子内部靠近检测腔室的一侧设有磁钢；检测腔室安装有步进电机,步进电机的输出轴上连接有可与输出轴同步转动的丝杆,丝杆的一侧固定有与其平行设置的导向杆,丝杆上安装有可以随着丝杆转动而上下运动的滑块,滑块的另一侧滑动套设在导向杆上,滑块上靠近计量腔室内磁钢的一侧安装有检测板,检测板上设有磁传感器。本发明气动计量泵测量精度高、结构设计紧凑、性能稳定,可以长期可靠工作。(The invention discloses a pneumatic metering pump, which comprises a pump body, wherein a metering chamber and a detection chamber are arranged in the pump body, the upper end of the metering chamber is provided with an air inlet and an air outlet, a liquid inlet check valve and a liquid outlet check valve are respectively arranged on a liquid inlet and a liquid outlet at the lower end of the metering chamber, a liquid level float is arranged in the metering chamber, and magnetic steel is arranged on one side, close to the detection chamber, in the liquid level float; the detection chamber is provided with a stepping motor, an output shaft of the stepping motor is connected with a lead screw capable of rotating synchronously with the output shaft, one side of the lead screw is fixed with a guide rod arranged in parallel with the lead screw, a slide block capable of moving up and down along with the rotation of the lead screw is arranged on the lead screw, the other side of the slide block is sleeved on the guide rod in a sliding manner, one side of the slide block, which is close to magnetic steel in the measurement chamber, is provided with a detection plate, and a magnetic sensor. The pneumatic metering pump has the advantages of high measurement precision, compact structural design, stable performance and long-term reliable work.)

1. The utility model provides a pneumatic measuring pump, includes the pump body, inside measurement cavity and the detection cavity of being equipped with of pump body, its characterized in that: the upper end of the metering cavity is provided with an air inlet and an air outlet, the lower end of the metering cavity is provided with a liquid inlet and a liquid outlet, and the liquid inlet and the liquid outlet are respectively provided with a liquid inlet check valve and a liquid outlet check valve; a liquid level floater capable of freely moving is arranged in the metering chamber, and magnetic steel is arranged on one side, close to the detection chamber, in the liquid level floater; the detection chamber is provided with a stepping motor, an output shaft of the stepping motor is connected with a screw rod capable of synchronously rotating with the output shaft, one side of the screw rod is fixed with a guide rod arranged in parallel with the screw rod, the screw rod is provided with a slide block capable of moving up and down along with the rotation of the screw rod, and the other side of the slide block is sleeved on the guide rod in a sliding manner; a detection plate is arranged on one side, close to the magnetic steel in the metering chamber, of the sliding block, and a magnetic sensor is arranged on the detection plate; the detection chambers at the upper end and the lower end of the guide rod are respectively provided with an upper limit switch and a lower limit switch; and a controller is arranged in the detection chamber and is respectively in control connection with the stepping motor, the limit switch and the detection plate through leads.

2. The pneumatic metering pump of claim 1, wherein: a flow guide disc is fixed below the air inlet and outlet in the metering chamber, and a plurality of flow guide holes are uniformly formed in the flow guide disc.

3. The pneumatic metering pump of claim 2, wherein: a safety valve floater is arranged in a through hole in the flow guide disc and positioned right below the air inlet and outlet, and magnetic steel is arranged in the safety valve floater; and a safety valve detection plate connected with the controller is arranged on one side of the air inlet and the air outlet of the metering chamber, and a reed pipe is arranged on the safety valve detection plate.

4. A pneumatic metering pump according to any one of claims 1 to 3, wherein: the air inlet and outlet are respectively connected with a negative pressure electromagnetic valve and a positive pressure electromagnetic valve through a main air path pipeline, the other end of the negative pressure electromagnetic valve is connected with a vacuum pump, the other end of the positive pressure electromagnetic valve is connected with an air compressor, and the main air path pipeline is provided with a main air path electromagnetic valve; the negative pressure electromagnetic valve, the positive pressure electromagnetic valve and the main air path electromagnetic valve are respectively connected with the controller.

5. The pneumatic metering pump of claim 4, wherein: the pneumatic metering pump further comprises an alarm device, and the alarm device is connected with the controller.

6. The pneumatic metering pump of claim 4, wherein: the limit switch is a photoelectric switch and consists of an optical transmitter and an optical receiver, and the sliding block is provided with a light barrier capable of cutting off the photoelectric switch.

7. A method for measuring a pneumatic metering pump, comprising the steps of:

step 1, when a controller is powered on, a photoelectric device of a lower limit switch is in a conducting state, the controller drives a stepping motor to rotate and drives a sliding block to move to the lower limit switch, a light barrier on the sliding block separates a transmitter and a receiver of the photoelectric switch to send a turn-off signal, and the controller receives the turn-off signal to complete zero calibration, which is called as a calibration step;

step 2, the controller controls the negative pressure electromagnetic valve to be opened, liquid flows into the metering chamber through the liquid inlet one-way valve, the liquid level floater rises along with the rise of the liquid level height, the controller controls the stepping motor to rotate to drive the sliding block to follow the position change of the liquid level floater after the magnetic sensor detects the position signal of the magnetic steel in the liquid level floater, and meanwhile, the controller records the rotating step number of the stepping motor; after the liquid level floater reaches the designated position, the negative pressure electromagnetic valve is closed, and the controller calculates the volume of the liquid in the metering chamber according to the liquid level height and the sectional area of the metering chamber, which is called as a suction step;

step 3, opening a positive pressure electromagnetic valve to enable liquid in the metering cavity to flow out of the metering cavity through a liquid outlet one-way valve under the driving of air pressure, controlling the rotation of the stepping motor to drive the sliding block to follow the position change of the liquid level floater by the controller after the magnetic sensor detects a position signal of magnetic steel in the liquid level floater, and simultaneously recording the rotating steps of the stepping motor by the controller; after the liquid level float reaches the designated position, the positive pressure electromagnetic valve is closed, and the controller calculates the volume of the liquid pumped out according to the height change of the liquid level and the sectional area of the metering chamber, which is called a pumping-out step.

8. The method of claim 7, wherein in the step 1, the step 2 and the step 3, the controller controls the stepper motor to rotate by sending a pulse signal to the stepper motor, and the pulse signal is divided into two types of forward rotation and reverse rotation, which correspond to the two rotation directions of the output shaft of the stepper motor.

9. The method for measuring a pneumatic metering pump according to claim 7, wherein in the steps 2 and 3 of the method, the controller calculates the liquid level height of the measured liquid according to the forward rotation type and the reverse rotation type of the pulse signals and the number of the pulse signals, thereby calculating the volumes of the sucked and pumped liquids.

Technical Field

The invention belongs to the technical field of metering pumps, and particularly relates to a pneumatic metering pump and a measuring method thereof.

Background

Metering pumps are common machines for fluid delivery and are characterized by the ability to maintain a constant flow rate independent of discharge pressure. Due to its outstanding features, metering pumps are now widely used in various industrial fields such as petrochemical industry, pharmaceuticals, food and the like.

The existing metering pump with higher accuracy mainly comprises: plunger type, diaphragm type, etc., wherein, the plunger type metering pump can cause abrasion to affect normal work because of the reciprocating relative motion between the plunger and the cavity; diaphragm metering pumps also suffer from variations in metering accuracy due to variations in the viscosity of the fluid being metered.

Disclosure of Invention

The invention aims to solve the problems and provides a pneumatic metering pump for measuring liquid with high precision and a measuring method thereof.

In order to achieve the purpose, the invention provides the following technical scheme:

the utility model provides a pneumatic measuring pump, includes the pump body, inside measurement cavity and the detection cavity of being equipped with of pump body, its characterized in that: the upper end of the metering cavity is provided with an air inlet and an air outlet, the lower end of the metering cavity is provided with a liquid inlet and a liquid outlet, and the liquid inlet and the liquid outlet are respectively provided with a liquid inlet check valve and a liquid outlet check valve; a liquid level floater capable of freely moving is arranged in the metering chamber, and magnetic steel is arranged on one side, close to the detection chamber, in the liquid level floater; the detection chamber is provided with a stepping motor, an output shaft of the stepping motor is connected with a lead screw which can synchronously rotate with the output shaft, one side of the lead screw is fixed with a guide rod which is arranged in parallel with the lead screw, the lead screw is provided with a slide block which can move up and down along with the rotation of the lead screw, the other side of the slide block is sleeved on the guide rod in a sliding manner, one side of the slide block, which is close to magnetic steel in the measurement chamber, is provided with a detection plate, and the detection; the detection chambers at the upper end and the lower end of the guide rod are respectively provided with an upper limit switch and a lower limit switch; and a controller is arranged in the detection chamber and is respectively in control connection with the stepping motor, the limit switch and the detection plate through leads.

As a further preferable scheme, a flow guide disc is fixed below the air inlet and outlet in the metering chamber, and a plurality of flow guide holes are uniformly formed in the flow guide disc.

As a further preferable scheme, a safety valve floater is arranged in a through hole in the flow guiding disc and positioned right below the air inlet and outlet, and magnetic steel is arranged in the safety valve floater; and a safety valve detection plate connected with the controller is arranged on one side of the air inlet and the air outlet of the metering chamber, and a reed pipe is arranged on the safety valve detection plate.

As a further preferred scheme, the air inlet and outlet are respectively connected with the negative pressure electromagnetic valve and the positive pressure electromagnetic valve through a main air path pipeline, the other end of the negative pressure electromagnetic valve is connected with the vacuum pump, the other end of the positive pressure electromagnetic valve is connected with the air compressor, the main air path pipeline is provided with the main air path electromagnetic valve, and the negative pressure electromagnetic valve, the positive pressure electromagnetic valve and the main air path electromagnetic valve are respectively connected with the controller.

As a further preferred scheme, the pneumatic metering pump further comprises an alarm device, and the alarm device is connected with the controller.

As a further preferred scheme, the limit switch is a photoelectric switch and consists of a light emitter and a light receiver, and a light barrier capable of cutting off the photoelectric switch is arranged on the sliding block.

A method for measuring a pneumatic metering pump, comprising the steps of:

step 1, when a controller is powered on, a photoelectric device of a lower limit switch is in a conducting state, the controller drives a stepping motor to rotate and drives a sliding block to move to the lower limit switch, a light barrier on the sliding block separates a transmitter and a receiver of the photoelectric switch to send a turn-off signal, and the controller receives the turn-off signal to complete zero point calibration;

step 2, the controller controls the negative pressure electromagnetic valve to be opened, liquid flows into the metering chamber through the liquid inlet one-way valve, the liquid level floater rises along with the rise of the liquid level height, the controller controls the stepping motor to rotate to drive the sliding block to follow the position change of the liquid level floater after the magnetic sensor detects the position signal of the magnetic steel in the liquid level floater, and meanwhile, the controller records the rotating step number of the stepping motor; after the liquid level floater reaches the designated position, the negative pressure electromagnetic valve is closed, and the controller calculates the volume of the liquid in the metering chamber according to the liquid level height and the sectional area of the metering chamber, which is called as a suction step;

step 3, opening a positive pressure electromagnetic valve to enable liquid in the metering cavity to flow out of the metering cavity through a liquid outlet one-way valve under the driving of air pressure, controlling the rotation of the stepping motor to drive the sliding block to follow the position change of the liquid level floater by the controller after the magnetic sensor detects a position signal of magnetic steel in the liquid level floater, and simultaneously recording the rotating steps of the stepping motor by the controller; after the liquid level float reaches the designated position, the positive pressure electromagnetic valve is closed, and the controller calculates the volume of the liquid pumped out according to the height change of the liquid level and the sectional area of the metering chamber, which is called a pumping-out step.

In the step 1, the step 2 and the step 3 of the method, the controller controls the stepping motor to rotate through a pulse signal sent to the stepping motor, wherein the pulse signal is divided into a forward rotation direction and a reverse rotation direction, and the forward rotation direction and the reverse rotation direction correspond to the forward rotation direction and the reverse rotation direction of an output shaft of the stepping motor respectively.

In the step 2 and the step 3 of the method, the controller calculates the liquid level height of the liquid to be measured according to the forward rotation type and the reverse rotation type of the pulse signals and the number of the pulse signals.

The invention has the following advantages:

(1) electric parts such as controller, stop device all set up in the detection cavity of keeping apart with the measurement cavity, realize the non-contact liquid level measurement to the liquid of being surveyed, can be applied to the accurate measurement pump sending of inflammable and explosive and highly corrosive liquid.

(2) The controller measures the height of the liquid according to the type and the number of the pulse signals, and the obtained measurement data are accurate and high in precision.

(3) Compared with plunger type and diaphragm type metering pumps, the pneumatic metering pump can not influence normal work due to abrasion in work, can not cause metering precision change due to viscosity change of metered liquid, and can realize high-precision metering under the condition of large flow.

(4) The structure design is compact, the performance is stable, and the long-term reliable work can be realized.

Drawings

FIG. 1 is a schematic view of the external structure of the pneumatic metering pump of the present invention;

FIG. 2 is a schematic view of the internal structure of the pneumatic metering pump of the present invention;

fig. 3 is a top view of a diaphragm of the present invention;

fig. 4 is a front sectional view of a diaphragm of the present invention;

FIG. 5 is a schematic diagram of the operation of the pneumatic metering pump controller of the present invention.

In the figure: 1-gas inlet and outlet; 2-a safety valve detection plate; 3-safety valve float; 4-a pump body; 5-a flow guide disc; 6-liquid level float; 7-magnetic steel; 8-liquid inlet one-way valve; 9-liquid outlet one-way valve; 10-a stepper motor; 11-a guide bar; 12-upper limit switch; 13-a magnetic sensor; 14-a slide block; 15-a controller; 16-flexible conductor; 17-a screw rod; 18-lower limit switch.

Detailed Description

In order to make those skilled in the art understand the technical means for implementing the present invention, the present invention is further described below with reference to the specific drawings.

As shown in fig. 1 to 5, the pneumatic metering pump of the present invention includes a pump body, a metering chamber a and a detection chamber B are disposed in the pump body, and is characterized in that: the upper end of the metering cavity A is provided with an air inlet and an air outlet 1, the lower end of the metering cavity A is provided with a liquid inlet and a liquid outlet, the liquid inlet and the liquid outlet are respectively provided with a liquid inlet check valve 8 and a liquid outlet check valve 9, a liquid level floater 6 capable of freely moving is arranged in the metering cavity A, and one side of the liquid level floater 6, which is close to the detection cavity, is provided with magnetic steel 7; the detection device is characterized in that a stepping motor 10 is installed in the detection chamber B, a lead screw 17 capable of rotating synchronously with the output shaft is connected to the output shaft of the stepping motor 10, a guide rod 11 arranged in parallel with the lead screw 17 is fixed to one side of the lead screw 17, a sliding block 14 capable of moving up and down along with the rotation of the lead screw 17 is installed on the lead screw 17, the other side of the sliding block 14 is sleeved on the guide rod 11 in a sliding mode, a detection plate is installed on one side, close to the magnetic steel 7 in the measurement chamber A, of the sliding block 14, a magnetic sensor 13 is arranged on the detection plate, upper and lower limit switches 12 and 18 are respectively arranged on the detection chamber B at the upper end and the lower end of the guide rod 11, a controller 15 is arranged in the detection chamber B, and the controller. In this embodiment, the controller 15 may be an 80C51 type general-purpose single chip microcomputer or a Programmable Logic Controller (PLC), and the controller 15 outputs a pulse signal to the stepping motor 10 to control the output shaft of the stepping motor 10 to rotate forward or backward on the one hand, and calculates the level of the liquid to be measured according to the forward rotation type and the backward rotation type of the pulse signal and the number of the pulse signal on the other hand; when the stepping motor 10 receives an output pulse of the controller 15, the output shaft of the stepping motor 10 enables the screw rod 17 to generate a fixed rotation angle, and when the controller 15 outputs a forward rotation pulse, the output shaft of the stepping motor 10 rotates along one direction, for example, the clockwise direction; when the controller 15 outputs the reverse rotation pulse, the output shaft of the stepping motor 10 rotates in another direction, for example, counterclockwise. In practical application, the detection precision can be effectively improved only by increasing the number of the subdivided steps of the stepping motor 10.

The lower part that is located into gas outlet 1 in the measurement cavity A is fixed with flow guide disc 5, has evenly seted up a plurality of water conservancy diversion holes on the flow guide disc 5, and flow guide disc 5 can prevent that high-pressure gas from entering into in the measurement cavity A can lead to liquid level float 6 to be strikeed and rock, influences the accuracy of measurement, and a plurality of water conservancy diversion holes on the flow guide disc 5 have disperseed airflow pressure, can make the air current steadily get into measurement cavity A to promote the smooth motion of liquid level float 6, realize measuring accurately.

A safety valve floater 3 is arranged in a through hole which is positioned right below the air inlet and outlet 1 in the flow guide disc 5, magnetic steel is arranged in the safety valve floater 3, a safety valve detection plate 2 connected with a controller 15 is arranged on one side of the air inlet and outlet 1 of the metering chamber A, and a reed pipe is arranged on the safety valve detection plate 2. When the liquid level gauge is normally used, the sliding block 14 is always positioned between the upper limit switch 12 and the lower limit switch 18, if the upper limit switch 12 sends a turn-off signal, the liquid level is full, and the negative pressure electromagnetic valve is immediately turned off; if the liquid level rises continuously due to the failure of the negative pressure solenoid valve or the failure of a controller, the working liquid enters the solenoid valve to damage the solenoid valve, and therefore, the float 3 provided with the safety valve can prevent the phenomenon. When the liquid level continues to rise, the liquid buoyancy supports the safety valve floater 3 and floats to the air inlet and outlet 1, and the safety valve floater 3 is attached to the air inlet and outlet 1 in a sealing mode to prevent the liquid level from further rising; meanwhile, the reed switch on the safety valve detection plate 2 is magnetized and conducted to send a signal, and the controller 15 turns off the main gas circuit electromagnetic valve after detecting the signal and sends out acousto-optic alarm.

The air inlet and outlet 1 is respectively connected with the negative pressure electromagnetic valve and the positive pressure electromagnetic valve through a main air pipeline, the other end of the negative pressure electromagnetic valve is connected with the vacuum pump, the other end of the positive pressure electromagnetic valve is connected with the air compressor, and the negative pressure electromagnetic valve, the positive pressure electromagnetic valve and the main air pipeline are arranged on the main air pipeline and are respectively connected with the controller. When the metering pump is in a suction state, the negative pressure electromagnetic valve is opened, the pressure in the metering chamber A is lower than the atmospheric pressure, liquid flows into the metering chamber A through the liquid inlet one-way valve 8, at the moment, the liquid level floater 6 rises, the magnetic sensor 13 detects a magnetic signal of magnetic steel in the liquid level floater 6, the controller 15 controls the stepping motor 10 to rotate to drive the sliding block 14 to rise to follow the position change of the liquid level floater 6, and meanwhile, the controller 15 records the rotating step number of the stepping motor 10; when the liquid level floater 6 reaches the set height, closing the negative pressure electromagnetic valve; and in the discharging state of the metering pump, the positive pressure electromagnetic valve is opened, so that the compressed gas in the air compressor enters the metering chamber A, the internal pressure of the metering chamber A is higher than the external pressure, and the liquid flows out of the metering chamber A through the liquid outlet one-way valve 9. At the moment, the magnetic sensor 13 detects the signal of the magnetic steel of the liquid level floater 6 and moves downwards along with the liquid level floater 6 under the driving of the stepping motor 10; when the controller 15 detects that the liquid level float 6 reaches the specified position, the positive pressure solenoid valve is closed, and the compressed gas is stopped from entering the metering chamber a, thereby stopping the liquid from flowing out.

The pneumatic metering pump is characterized by further comprising an alarm device, wherein the alarm device is connected with the controller 15 and used for giving out sound and light alarm when the controller 15 detects abnormality.

The limit switches 12 and 18 are photoelectric switches and are composed of two parts, namely a light emitter and a light receiver, and the sliding block 14 is provided with a light barrier capable of cutting off the photoelectric switches.

A method for measuring a pneumatic metering pump, comprising the steps of:

step 1, when the controller 15 is powered on, the photoelectric device of the lower limit switch 18 is in a conducting state, at this time, the controller 15 drives the stepping motor 10 to rotate and drives the sliding block 14 to move to the lower limit switch 18, a light barrier on the sliding block 14 separates a transmitter and a receiver of the photoelectric switch 12 to send a turn-off signal, and the controller 15 receives the turn-off signal to complete zero calibration, which is called as a calibration step;

step 2, the controller 15 controls the negative pressure electromagnetic valve to be opened, liquid flows into the metering chamber A through the liquid inlet one-way valve 8, the liquid level floater 6 rises along with the rise of the liquid level height, after the magnetic sensor 13 detects a position signal of the magnetic steel 7 in the liquid level floater 6, the controller 15 controls the stepping motor 10 to rotate to drive the sliding block 14 to follow the position change of the liquid level floater 6, and meanwhile, the controller 15 records the rotating steps of the stepping motor 10; after the liquid level floater 6 reaches the designated position, the negative pressure electromagnetic valve is closed, and the controller 15 calculates the liquid volume in the metering chamber A according to the liquid level height and the sectional area of the metering chamber, which is called as a suction step;

step 3, opening a positive pressure electromagnetic valve to enable liquid in the metering chamber A to flow out of the metering chamber A through the liquid outlet one-way valve 9 under the drive of air pressure, controlling the rotation of the stepping motor 10 by the controller 15 to drive the slider 14 to follow the position change of the liquid level floater 6 after the magnetic sensor 13 detects a position signal of the magnetic steel 7 in the liquid level floater 6, and simultaneously recording the number of steps of the rotation of the stepping motor 10 by the controller 15; after the liquid level float 6 reaches the specified position, the positive pressure solenoid valve is closed, and the controller 15 calculates the volume of the liquid to be pumped out from the height change of the liquid level and the sectional area of the metering chamber a, which is called a pumping-out step.

In the 1 st step, the 2 nd step and the 3 rd step of the measuring method, the controller 15 controls the stepping motor 10 to rotate by a pulse signal sent to the stepping motor 10, wherein the pulse signal is divided into a forward rotation direction and a reverse rotation direction, and the forward rotation direction and the reverse rotation direction respectively correspond to the forward rotation direction and the reverse rotation direction of the output shaft of the stepping motor 10; in the steps 2 and 3, the controller 15 calculates the liquid level height of the liquid to be measured according to the forward rotation type and the reverse rotation type of the pulse signals and the number of the pulse signals, so as to calculate the volumes of the liquid to be sucked and pumped.

It will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and that various changes and modifications may be made to the present invention, for example, the magnetic sensor on the slider may be a proximity switch, a hall element or a reed switch, and the lead screw may be a code strip or a flexible cord.