Pressure compensation device for piston type pressure gauge

Abstract

The utility model relates to a pressure compensation device for a piston type pressure gauge, and belongs to the technical field of measurement standard equipment. In order to overcome the defects that the output pressure of a piston type pressure gauge in the prior art is discontinuous and only non-integer pressure values can be output, the input end of the pressure compensation device is the output end of the piston type pressure gauge, the output of the pressure compensation device is compensated pressure output, and the pressure compensation device comprises a differential pressure measurement module, the isolating valve is connected with the differential pressure measuring module in parallel and controls opening and closing of the pressure compensation device, a pressure regulating device used for pressure compensation is installed at the output end of the isolating valve, the output end of the pressure regulating device outputs compensated pressure, and the isolating valve and the pressure regulating device are controlled by a control unit. The control unit collects measurement data of the pressure regulating device of the differential pressure measuring module and the piston type pressure gauge or a sensor in the piston type pressure gauge, compensation and correction can be carried out on output pressure of the piston type pressure gauge, the pressure output range is continuous through the compensation device, and errors of the compensation device are small.

Description

Technical Field

[0001] The utility model relates to a pressure compensation device, in particular to a pressure compensation device for a piston pressure gauge, belonging to the technical field of measurement standard equipment. Background Art

[0002] Pressure (P) is not an independent fundamental physical quantity, but rather a derivative of mass and length. Pressure is defined as: P = F / A, where F is the force and A is the area supporting the force. A piston pressure gauge, also known as a deadweight pressure gauge, operates based on the principle of hydrostatic equilibrium and Pascal's law.

[0003] Hydrostatic balance is achieved by balancing the force acting on the piston system with the reaction force generated by the pressure medium. The piston system consists of a piston and a cylinder (piston barrel), which form an excellent dynamic seal. The area (effective area) of the piston is known. When a known force acts on one end of the piston, the pressure medium at the other end of the piston will generate a force equal to and opposite to the known force to balance the force. Therefore, the pressure of the pressure medium in the system can be calculated by the force and the effective area of ​​the piston. In practical applications, the force is usually obtained by multiplying the mass of the weight by the acceleration of gravity at the place of use. There are many types of piston pressure gauge structures. The structural principle of a typical high-precision fully automatic piston pressure gauge is as follows. Figure 1 shown.

[0004] The piston pressure gauge has the characteristics of high accuracy, high reproducibility and high reliability, stable output and certain self-compensation capability. It is a widely used standard pressure measuring instrument.

[0005] Existing piston pressure gauges have the following deficiencies: (1) The output pressure of the piston pressure gauge is determined by the loaded weight and the effective area of ​​the piston, and its output pressure value is not continuous; (2) For high-precision piston pressure gauges (such as the 0.005-level gas piston pressure standard device), its output mathematical model and experiments show that its output is significantly affected by factors such as ambient temperature and atmospheric pressure, which cannot be ignored. Therefore, its output value is a non-integer "calculated value". For example, if the output is set to 110kPa, the actual machine display output is 109.92612kPa. Summary of the Invention

[0006] The purpose of the utility model is to solve the shortcomings of the existing piston pressure gauge that the output pressure is discontinuous and can only output non-integer pressure values, and to provide a pressure compensation device to compensate and correct the output pressure of the piston pressure gauge. The compensation device has a certain working range to make the pressure output range continuous, and the error of the compensation device is relatively small.

[0007] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0008] A pressure compensating device for a piston pressure gauge, wherein the input end is the output end of the piston pressure gauge, and the output is a compensated pressure output. The device is special in that it includes a differential pressure measuring module installed between the input and output ends to measure the pressure difference between the input and output sides of the pressure compensating device, an isolation valve connected in parallel with the differential pressure measuring module and controlling the opening and closing of the pressure compensating device, a pressure regulating device for pressure compensation installed at the output end of the isolation valve, and the output end of the pressure regulating device is the compensated pressure output. The isolation valve and pressure regulating device are controlled by a control unit, and the control unit collects measurement data from the pressure regulating device of the differential pressure measuring module and the piston pressure gauge or a sensor within the piston pressure gauge;

[0009] Preferably, the differential pressure measurement module is connected in parallel with a protection device to prevent it from overshooting;

[0010] Preferably, the protection device includes two overflow valves connected in parallel in positive and negative directions and a manual isolation valve;

[0011] Preferably, the differential pressure measurement module is one of a differential pressure digital pressure gauge, a compensated micro differential pressure gauge, a differential pressure transmitter, and a differential pressure sensor;

[0012] Preferably, the pressure regulating device comprises a fine-tuning pressure regulator connected to the isolation valve, and the fine-tuning pressure regulator is controlled by a stepping motor to adjust the pressure;

[0013] Preferably, the control unit includes a display, a button and a control circuit, and the control unit is electrically connected to the controller host of the fully automatic piston pressure gauge or is electrically connected to the speed sensor and displacement sensor of the piston pressure gauge to collect the speed and piston displacement of the piston pressure gauge;

[0014] Preferably, the pressure compensation device also includes a video acquisition device for acquiring the current pressure of the piston pressure gauge. Two video acquisition devices are provided, which are respectively located on one side of the differential pressure measurement module and the controller host of the fully automatic piston pressure gauge. The video acquisition device is electrically connected to the control unit.

[0015] The utility model is applied to the output end of the piston pressure gauge, and can compensate the output of the piston pressure gauge. The compensation is performed by controlling the opening and closing of the isolation valve to limit the differential pressure value of the positive and negative ends of the differential pressure measurement module. The working state of the piston pressure gauge is determined by detecting the rotation speed of the weight of the piston pressure gauge. Through compensation, the output pressure value is continuous and an integer pressure value can be output. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the mechanism of the prior art;

[0017] Figure 2 This is a schematic structural diagram of Example 1 of the present utility model;

[0018] Figure 3 This is a structural diagram of Example 2 of the present utility model.

[0019] In the figure: 1-weight group; 2-piston rod; 3-piston cylinder; 4-displacement sensor; 5-tachometer; 6-temperature sensor; 7-acceleration motor; 8-large weight adding mechanism; 9-medium weight adding mechanism; 10-small weight adding mechanism; 11-vacuum cover; 12-vacuum gauge; 13-vacuum pump; 14-pressure reducing pump; 15-air source; 16, 17-solenoid valve; 18-piston pressure gauge controller host; 19-pressure sensor; 20-atmospheric pressure sensor; 21-control unit; 22-differential pressure measurement module; 23-overflow valve; 24-manual isolation valve; 25-isolation valve; 26-fine-tuning pressure regulator; 27-stepping motor; 28-video acquisition device. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example 1. Figure 2 A pressure compensating device for a piston pressure gauge is shown, wherein its input is the output of the piston pressure gauge, and its output is the compensated pressure output. The device includes a differential pressure measuring module 22 installed between the input and output ends to measure the pressure difference between the input and output of the pressure compensating device, an isolation valve 25 connected in parallel with the differential pressure measuring module 22 and controlling the opening and closing of the pressure compensating device, a pressure regulating device for pressure compensation installed at the output end of the isolation valve 25, and the output end of the pressure regulating device is the compensated pressure output. The isolation valve 25 and the pressure regulating device are controlled by a control unit 21, which collects measurement data from the differential pressure measuring module 22, the pressure regulating device, and the piston pressure gauge or the sensor within the piston pressure gauge;

[0022] The isolation valve 25 in this embodiment adopts a magnetic control valve;

[0023] Wherein, the differential pressure measurement module 22 is one of a differential pressure digital pressure gauge, a compensated micro differential pressure gauge, a differential pressure transmitter, and a differential pressure sensor;

[0024] The pressure regulating device includes a fine-tuning pressure regulator 26 connected to the isolation valve 25, and the fine-tuning pressure regulator 26 is controlled by a stepping motor 27 to adjust the pressure;

[0025] Among them, the control unit 21 includes a display, buttons and a control circuit. The control unit 21 is electrically connected to the controller host of the fully automatic piston pressure gauge or to the speed sensor and displacement sensor of the piston pressure gauge to collect the speed and piston displacement of the piston pressure gauge.

[0026] Determine the working status of the piston pressure gauge, control the isolation valve to open when the piston pressure gauge is in an unstable state to prevent the differential pressure measurement module from overshooting, control the isolation valve to close when the piston pressure gauge is in a stable state and directly collect the pressure measurement value of the differential pressure measurement module, calculate the compensation pressure and adjust the output pressure to the set value by controlling the pressure regulating device.

[0027] Working Principle: By default, the control unit keeps the isolation valve open, disabling the pressure compensation device. This ensures connectivity across the differential pressure measurement module until the piston gauge output stabilizes, preventing overshoot. When the piston gauge begins operating, the control unit monitors its status. Once the output stabilizes, the control unit closes the isolation valve, opening the pressure compensation device to isolate the input and output. The control unit calculates the difference between the piston gauge output and the target value to determine the compensation value. The control unit then controls the pressure regulator to adjust the output pressure until the differential pressure measurement module reaches the compensation value, achieving the target output. During operation, the control unit measures the piston gauge speed in real time. If the speed is too low, the control unit closes the isolation valve to prevent overshoot. If overpressure occurs on either side of the differential pressure measurement module, the relief valve within the protection device automatically opens to maintain a safe pressure differential. In an emergency, the control unit can also open the manual isolation valve within the protection device to balance the pressures.

[0028] Example 2. Figure 3 The pressure compensation device for a piston pressure gauge shown is basically the same as that of Example 1. The pressure compensation device also includes a video acquisition device 28 for acquiring the current pressure of the piston pressure gauge. Two video acquisition devices 28 are provided, which are respectively located on one side of the differential pressure measurement module 22 and the controller host 18 of the fully automatic piston pressure gauge. The video acquisition device 28 is electrically connected to the control unit 21.

[0029] When the piston pressure gauge is in a stable state, the isolation valve is controlled to be closed and the pressure measurement value of the differential pressure measurement module is read through the video acquisition and recognition device, the compensation pressure is calculated, and the output pressure is adjusted to the set value through the control pressure regulating device.

[0030] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent replacements for some of the technical features therein. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A pressure compensating device for a piston pressure gauge, wherein the input end is the output end of the piston pressure gauge and the output is the compensated pressure output, characterized in that: The invention comprises a differential pressure measuring module (22) installed between the input end and the output end for measuring the pressure difference between the input and output sides of a pressure compensation device, an isolation valve (25) connected in parallel with the differential pressure measuring module (22) and controlling the opening and closing of the pressure compensation device, a pressure regulating device for pressure compensation installed at the output end of the isolation valve (25), the output end of the pressure regulating device is a pressure output after compensation, the isolation valve (25) and the pressure regulating device are controlled by a control unit (21), and the control unit (21) collects measurement data of the pressure regulating device of the differential pressure measuring module (22) and the piston pressure gauge or the internal sensor of the piston pressure gauge.

2. A pressure compensation device for a piston pressure gauge according to claim 1, characterized in that: The differential pressure measurement module (22) is connected in parallel with a protection device for preventing overshoot.

3. The pressure compensation device for a piston pressure gauge according to claim 2, characterized in that: The protection device comprises two overflow valves (23) connected in parallel in both positive and negative directions and a manual isolation valve (24).

4. A pressure compensation device for a piston pressure gauge according to claim 1, 2 or 3, characterized in that: The differential pressure measurement module (22) is one of a differential pressure digital pressure gauge, a compensated micro differential pressure gauge, a differential pressure transmitter, and a differential pressure sensor.

5. The pressure compensation device for a piston pressure gauge according to claim 4, characterized in that: The pressure regulating device comprises a fine-tuning pressure regulator (26) connected to the isolation valve (25), and the fine-tuning pressure regulator (26) is controlled by a stepping motor (27) to regulate the pressure.

6. The pressure compensation device for a piston pressure gauge according to claim 4, characterized in that: The control unit (21) comprises a display, a button and a control circuit. The control unit (21) is electrically connected to a controller host of a fully automatic piston pressure gauge or to a rotation speed sensor and a displacement sensor of the piston pressure gauge to collect the rotation speed and piston displacement of the piston pressure gauge.

7. The pressure compensation device for a piston pressure gauge according to claim 6, characterized in that: The pressure compensation device further includes a video acquisition device (28) for acquiring the current pressure of the piston pressure gauge. Two video acquisition devices (28) are provided, which are respectively located on one side of the differential pressure measurement module (22) and the controller host (18) of the full-automatic piston pressure gauge. The video acquisition devices (28) are electrically connected to the control unit (21).

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