RU1795433C - Pressure setting device - Google Patents

Abstract

The invention relates to measuring technique and can be used as an exemplary tool in the verification and calibration of pressure measuring instruments. The purpose of the invention is to increase the accuracy of the pressure setting. For this purpose, the device for setting the pressure, in addition to the controlled electromagnet in the form of a movable 1 and fixed 2 parts, an uncompressed piston 3, a cylinder 4 of an input 5 and an output 7 of an electric valve, a source of high pressure 6, comprises an electromagnetic gap sensor 8, a regulator 9, block 10 control valves and digital-to-analog converter 11 current. Thanks to the additional introduction of the control loop for the magnitude of the gap of the electromagnet, an increase in the accuracy of the pressure setting is achieved. 1 ill. (l C

Description

The invention relates to measuring technique and can be used as an exemplary tool in the verification and calibration of pressure measuring instruments.

The purpose of the invention is to increase the accuracy of the pressure reference.

The drawing shows a structural diagram of the device.

The device contains a controlled electromagnet in the form of a movable 1 and a fixed. 2 parts. The movable part 1 is connected to a non-sealed piston 3. Cylinder 4 is connected to a high pressure source 6 through an inlet solenoid valve 5 and to the atmosphere through an outlet solenoid valve 7. Between the movable 1 and the fixed part 2 of the electromagnet, an electromagnet gap sensor 8 is installed, the output of which is connected to the input of the controller 9, one output of which is connected to the input of the control unit 10 of the electric valves, and Some outputs of the unit 10 are connected to the control inputs of the electric valve 5, and others, with the control inputs of the electrovalve 7. Other outputs of the controller 9 are connected to the input of the digital-analog converter 11, the output of which is connected to the winding of the fixed part 2 of the electromagnet.

The device operates as follows.

When the electromagnet is de-energized, according to the command of the regulator 9, which passes through the solenoid valve control unit 10, the inlet solenoid valve 5 opens through which the working fluid enters the cylinder 4. As a result, the piston 3 rises to a certain fixed position, characterized by a maximum gap b max between the movable 1 and the fixed part 2 of the electromagnet.

The regulator 9 compares the current value of the gap b with the maximum value. When equality is reached, the command of the regulator 9, coming through the solenoid valve control unit 10, closes the solenoid valve 5 and the regulator 9 generates a digital-analog input code

a converter 11 that supplies current. corresponding to a given pressure, into the winding of an electromagnet that creates a force Pz, and hence the pressure P.

The pressure P created by the piston 3, taking into account (2), is equal to

G

Where

„B

K coefficient

2G-. i PROPORTIONS

onalities.

Since for a specific value of the set pressure, according to the command of the regulator 9, the corresponding fixed value of the current is set in the electromagnet winding, it can be seen from the expression above that the set pressure is measured indirectly by measuring the value of the air gap b.

The controller 9 compares the current value of the gap b with the reference value g0. If d d0, then, according to the command of the regulator 9, supplied through the control unit of the electrovalves 10, the output electrovalve 7 opens, releasing the excess working fluid until the piston 3 is lowered by the force Pe and falls to the position corresponding to the clearance d d0.

If after a certain time interval the current gap value b becomes less than the reference value 60, i.e. b 60 then, upon the command of the regulator 9, which is supplied through the solenoid valve control unit 10, the inlet solenoid valve 5 is opened and is in the open state until the piston 3 rises and occupies the position corresponding to the clearance b 60

Thus, the set pressure value is set by the current value in the electromagnet winding, followed by stabilization of the air gap value b to 60, and therefore, stabilization of the pressure value to the set value. "

Claims (1)

SUMMARY OF THE INVENTION A pressure setting device comprising an unsealed piston in a cylinder connected to an output electrovalve and an inlet electrovalve connected to a high pressure source, as well as an electromagnet and a regulator, characterized in that, in order to increase the accuracy of the pressure setting therein introduced an electromagnet gap sensor, a digital-to-analog current converter and a solenoid valve control unit, wherein the electromagnet is made in the form of a fixed part, equipped with a winding that is connected to the output of the digital-to-analog current converter, and a movable part, connected to the unsealed piston, the output of the electromagnet gap sensor is connected to the input of the controller, the first output of which is connected to the input digital-to-analog current converter, and the second output is with the input of the electric control unit valves connected by the first and second input and output electrical outputs to the control inputs of the corresponding valves.