CN202177433U - Electric drive piston type standard metering device for micro-flow - Google Patents

Abstract

The utility model discloses an electrically driven piston type measuring standard device for micro flow rate of liquid. The stepper motor is connected to one end of the ball screw through a reducer and a rigid coupling, and the other end is slidingly connected to the piston hole; the piston cylinder is connected to the water outlet of the solenoid valve through a three-way joint, and the water inlet of the solenoid valve is connected to the water tank; The guide rails parallel to the ball screw are respectively installed on the two beams of the base, and the two proximity switches are respectively installed at both ends of a guide rail, and are electrically connected with the input terminals of the lower PLC of the control system; the sliders of the two guide rails are equipped with The concave connection block, the screw nut and the end of the piston are all fixed on the side of the connection block; a grating scale is installed on one side of the other guide rail, and a grating head is installed under the L-shaped connection plate installed on the concave connection block. Adopting the piston principle and using the grating ruler to measure the moving distance of the piston, the position of the piston is fed back to the control system, which can control the speed, time and position of the piston movement, and measure and calibrate the small flow.

Description

An electric-driven piston type liquid micro-flow measurement standard device

technical field

The utility model relates to a micro-flow measurement standard device, in particular to an electric-driven piston-type liquid micro-flow measurement standard device.

Background technique

With the rise of semiconductor manufacturing, bioengineering, medical chemical industry and other industries, the flow measurement has been extended to the low end, and the measurement demand of small flow and micro flow has gradually become prominent. The research on microfluidics and the demand for micro-flow metering accuracy have also attracted the attention of more and more scientific workers, and micro-flow metering has become one of the urgently needed metering technologies in the field of fluid metering.

There are two ways to produce the flow source of the traditional liquid flow standard device. One is the constant pressure flow source. This method has stable flow, but the general voltage stabilization equipment is bulky and expensive; the other is to rely on the flow pump to provide flow. The flow is pulsating and the stability is poor. The above two methods, due to various shortcomings, cannot be applied to the liquid micro-flow metering verification system. At present, commonly used micro flow meters such as thermal mass flow meters and Corian mass flow meters are used in the measurement of micro fluids. At the same time, micro fluid control components such as micro valves, micro pumps, and micro flow meters are also increasingly used. widely used. However, since there is currently no verification procedure for microfluidic control components such as micro valves, micro pumps, and micro flow meters in the country, it is difficult to guarantee the accuracy of the results of such components, and then the accuracy of their detection data, so a complete set is urgently needed Liquid micro-flow measurement standard device.

Summarize the deficiencies of the prior art as follows:

1. There is no perfect liquid micro-flow measurement standard device, which cannot meet the current measurement needs of liquid micro-flow.

2. The fluid source is a key factor affecting the verification accuracy of the micro-flow system, and a fluid source device that can provide a stable flow rate and can adjust the flow rate has become an important problem.

Contents of the invention

Aiming at the deficiency of the background technology, the purpose of the utility model is to provide an electrically driven piston type liquid micro-flow measurement standard device.

The technical scheme that the utility model solves its technical problem adopts is:

The stepping motor in the utility model is connected with one end of the ball screw supported on one side of the device base through a reducer and a rigid coupling, and the other end of the ball screw extends into the piston hole, and is slidably connected with the piston hole through a guide ring; One end of the piston cylinder is connected to the other side of the device base, the other end of the piston cylinder is connected to the water outlet of the solenoid valve installed on the side of the water tank through a three-way joint, and the water inlet of the solenoid valve is connected to the water tank; A guide rail parallel to the ball screw is installed on the two beams, and two proximity switches are respectively installed at both ends of a guide rail, that is, the starting and ending positions of the piston, and the two proximity switches are connected to the input terminals of the lower PLC of the control system. Electrical connection; slide blocks are respectively installed on the two guide rails, and concave connection blocks are installed on the two slide blocks, and the screw nut and the end of the piston matched with the ball screw are fixed on the side of the concave connection block together; located on the other guide rail A grating scale parallel to the ball screw is installed on the base of the grating scale on one side, an L-shaped connecting plate is installed on the concave connecting block, and a grating head matching the grating scale is installed under the L-shaped connecting plate.

The base of the device has an upwardly inclined angle of 5° towards the direction of the piston cylinder.

Compared with the background technology, the beneficial effects of the utility model are:

1. The electric-driven piston-type liquid micro-flow measurement standard device of the utility model is a relatively complete measurement verification system, which can measure mass flow meters, micro-valves, micro-pumps, etc. with a micro-flow range of 0.1ml/h~1000ml/h Perform verification calibration. The expanded uncertainty of the device is (0.5~1.0)% (k=2).

2. The whole system adopts the piston principle, and uses the grating scale to measure the moving distance of the piston, and at the same time feeds back the position of the piston to the control system; the control system consists of a host computer and a lower computer, which can control the speed, time and position of the piston. This can not only quickly and conveniently carry out small flow control, but also improve the measurement accuracy of the small flow of the system.

Description of drawings

Fig. 1 is the structural principle schematic diagram of the utility model.

Fig. 2 is a perspective view of the utility model.

In the figure: 1. Stepper motor, 2. Reducer, 3. Rigid coupling, 4. Lock nut, 5. Bearing cover, 6. Deep groove ball bearing, 7. Grating ruler, 8. L-shaped connecting plate , 9. Screw nut, 10. Ball screw, 11. Guide ring, 12. Spring retaining ring, 13. Piston, 14. Piston cylinder, 15. Solenoid valve, 16. Water tank, 17. O-ring, 18. Grid Lai circle, 19, wear-resistant band, 20, guide rail, 21, slide block, 22, device base, 23, grating ruler base, 24, proximity switch, 25, concave connection block, 26, connection cover.

Detailed ways

The utility model will be further described below in conjunction with the accompanying drawings and embodiments, and the purpose and effect of the utility model will become more obvious.

As shown in Figure 1 and Figure 2, the electric drive piston type liquid micro-flow measurement standard device of the utility model includes a stepping motor 1, a reducer 2, a rigid coupling 3, a lock nut 4, a bearing cover 5, and a deep groove ball Bearing 6, grating ruler 7, L-shaped connecting plate 8, screw nut 9, ball screw 10, guide ring 11, spring retaining ring 12, piston 13, piston cylinder 14, solenoid valve 15, water tank 16, and O-shaped sealing ring 17. Gray ring 18, wear-resistant belt 19, guide rail 20, slider 21, device base 22, grating ruler base 23, proximity switch 24, concave connection block 25, connection sleeve 26 and control system. Wherein, the stepper motor 1 is connected to one end of the ball screw 10 supported on one side of the device base 22 through the reducer 2, the rigid coupling 3, and the connecting sleeve 26, and the other end of the ball screw 10 extends into the hole of the piston 13. The guide ring 11 is slidingly connected with the hole of the piston 13 , and the guide ring 11 is fixed on the end of the ball screw 10 with the spring retaining ring 12 . The stepping motor 1 is used to drive the speed reducer 2 to rotate forward and backward to drive the ball screw 10 to rotate. The ball screw 10 and the reducer 2 are locked and connected through the rigid coupling 3, and at the same time, it is necessary to ensure that the stepping motor 1, the reducer 2, the rigid coupling 3, the ball screw 10 and the piston 13 are on the same axis. The connecting sleeve 26 fixes the reducer 2 on the device base 22 and provides a rotation space for the rigid coupling 3 at the same time. The deep groove ball bearing 6 provides support for the ball screw 10 when it rotates, and it is pressed tightly with the bearing cover 5; at the same time, the lock nut 4 locks the deep groove ball bearing 6 to avoid the axial force generated when the ball screw 10 rotates axially. Pull out the deep groove ball bearing 6.

One end of the piston cylinder 14 is connected with the other side of the device base 22, and the other end of the piston cylinder 14 is connected with the water outlet of the electromagnetic valve 15 installed on the side of the water tank 16 through a three-way joint, and the outlet of the piston cylinder is sealed with an O-shaped sealing ring 17. Sealing, the water inlet of electromagnetic valve 15 is connected with water tank 16. The piston head of the piston 13 is closely installed with the piston cylinder 14, and the gray ring 18 is used for sealing and the wear-resistant belt 19 is used for guiding.

The device base 22 has an angle of 5° upward inclination towards the direction of the piston cylinder 14 to ensure that when the piston cylinder 14 is filled with liquid and leaves bubbles, it is convenient for the bubbles to be discharged from the piston cylinder 14 smoothly. A guide rail 20 parallel to the ball screw 10 is installed on the two beams on both sides of the device base 22, and a slide block 22 is respectively installed on the two guide rails 20. The two slide blocks 22 are equipped with a concave connecting block 25, which is connected with the ball screw. The screw nut 9 and the end of the piston 13 that the screw rod 10 matches are all fixed on the side of the concave connection block 25; The coaxiality of the rigid coupling 3, the ball screw 10 and the piston 13. Two proximity switches 24 are respectively installed on the two ends of a guide rail 20, i.e. the initial and end positions of the piston 13, are electrically connected with the input terminals of the lower PLC of the control system, and feedback the zero position and the end position of the piston 13 to control The start and stop of piston 13 moving back and forth. A grating scale 7 parallel to the ball screw 10 is installed on the grating scale base 23 on one side of the other guide rail, an L-shaped connecting plate 8 is installed on the concave connecting block 25, and the grating scale 7 is closely installed under the L-shaped connecting plate 8. The grating ruler 7 feeds back the position of the piston 13 to the control system; the control system consists of a host computer and a lower computer, which can control the movement speed, time and position of the piston 13 . The L-shaped connecting plate 8 makes the concave connecting block 25 and the grating head of the grating ruler 7 on the same horizontal plane, so as to ensure that the grating ruler 7 can move synchronously with the piston 13 and measure accurately when the ball screw 10 rotates forward and backward to drive the piston 13 to move forward and backward. The distance the piston moves back and forth.

As shown in Figure 2, the working process of the present utility model is:

Taking the piston cylinder 14 as the metering volume standard, the device drives the standard metering piston cylinder 14 and the piston 13 through the stepping motor 1 to generate a fluid source, which flows through the tested flowmeter through the three-way interface; the piston cylinder 14 cooperates with the grating ruler 7 to form a flow measurement system , the grating ruler 7 is installed on the side of the ball screw 10, and feeds back the position of the piston 13 to the control system; the control system is composed of a host computer and a lower computer, which can control the movement speed, time, and position of the piston 13; using a high-precision electronic balance, through Calculate the fluid medium to push the piston 13 to discharge the fluid mass in the piston cylinder 14 within a certain measurement time to calibrate the flowmeter.

The feature of the utility model piston-type liquid micro-flow metering standard device is that the invention point is: the stepping motor drives the reducer to carry out positive and negative rotation to drive the ball screw to rotate, and the ball screw drives the piston to move back and forth, before and after the piston drives the grating ruler. While the moving response is fast, it can also ensure high-precision control and measurement; the guide rails and sliders installed on the two beams on the base provide support for the connecting block, which not only ensures the stepping motor, reducer, rigid coupling, and ball screw. The coaxiality with the piston prevents the measurement uncertainty caused by the left and right swing of the connecting block; the base of the device has an inclination of 5° to ensure that when the piston cylinder is filled with liquid and there are air bubbles, it is convenient for the bubbles to discharge smoothly from the piston cylinder; The unique design not only tightly connects the stepper motor and reducer with the device base, but also provides space for the rigid coupling to connect the reducer with the ball screw; each part of the electric-driven piston type liquid micro-flow measurement standard device is relatively independent , It is very convenient to install and maintain.

Claims (2)

1. An electric-driven piston-type liquid micro-flow measurement standard device, characterized in that: the stepper motor (1) is connected to the device supported on one side of the device base (22) via a reducer (2), a rigid coupling (3) One end of the ball screw (10) is connected, and the other end of the ball screw (10) extends into the hole of the piston (13), and is slidingly connected with the hole of the piston (13) through the guide ring (11); one end of the piston cylinder (14) is connected to the device The other side of the base (22) is connected, the other end of the piston cylinder (14) is connected to the water outlet of the solenoid valve (15) installed on the side of the water tank (16) through a three-way joint, and the water inlet of the solenoid valve (15) is connected to the water tank (16) connection; a guide rail (20) parallel to the ball screw (10) is respectively installed on two beams located on both sides of the device base (22), and two proximity switches (24) are respectively installed on a guide rail (20 ), namely the start and end positions of the piston (13), two proximity switches (24) are electrically connected to the input terminals of the lower PLC of the control system; slide blocks (22) are respectively installed on the two guide rails (20) , the two sliders (22) are equipped with a concave connecting block (25), and the end of the screw nut (9) and the piston (13) matched with the ball screw (10) are fixed on the concave connecting block (25) Side; the grating scale (7) parallel to the ball screw (10) is installed on the grating scale base (23) on the other side of the guide rail, and the L-shaped connecting plate (8) is installed on the concave connecting block (25), A grating head matched with the grating ruler (7) is housed under the L-shaped connecting plate (8). 2. An electric-driven piston-type liquid micro-flow metering standard device according to claim 1, characterized in that: the device base (22) has an upwardly inclined angle of 5° towards the direction of the piston cylinder.

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