Digital piston type pressure gauge system and measuring method for verification and calibration work thereof

Abstract

The invention relates to the field of instruments and meters, and particularly discloses a measurement method for verification and calibration work of a digital piston type pressure gauge system, the system comprises a piston system, a force value sensing assembly, a positioning system, a pressure medium circulating system, a pressure output system and a control unit, and the core adopts a high-precision force value sensor to replace a traditional weight. Point contact force value transmission is achieved through a conduction steel ball, a piston motor is matched to drive a rotating disc to be linked with a rotating contact, stable rotation of a piston rod is ensured, and a medium oil film is formed. The control unit receives signals of the sensor and the piston position indicator and automatically completes pressure adjustment, data acquisition and error calculation. The force value transmission precision reaches 0.0005%, multi-range and multi-instrument measurement requirements can be met through a multi-stage piston structure and a multi-pressure-measuring-port design, full-process automation is achieved, and in addition, accurate output of all pressure points in the measurement range can be achieved by means of the wide-range sensing capacity of the high-precision force value sensor and the fine adjusting function of the pressure adjusting unit.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of instruments and meters, and particularly relates to a digital piston pressure gauge system, and further relates to a measurement method for the calibration and verification of the digital piston pressure gauge system. BACKGROUND

[0002] In high-end industrial fields such as aerospace, weapons, and ships, and in the scene of metrological calibration, the accuracy and reliability of pressure measurement directly determine the product quality, engineering safety, and effectiveness of value transfer. As the core standard instrument for pressure measurement, the piston pressure gauge, designed according to classical physical principles, plays a crucial role in pressure value transfer due to its stable pressure reproduction. It is the core bridge connecting the national pressure reference and various industrial pressure measurement instruments. P = F / S

[0003] Traditional piston pressure gauges and existing improved automatic piston pressure gauges still have many technical bottlenecks that are difficult to overcome in practical applications, severely restricting the precision improvement, efficiency optimization, and digital development process of pressure measurement: First, the accuracy of the force value source is limited and easily affected by environmental interference. Traditional piston pressure gauges rely on standard weights to provide the core force value F , but the national metrological regulation only requires a 0.001% mass error for the highest grade non-reference weight, and the weight mass will change slightly due to environmental factors such as temperature and humidity. At the same time, the weight of the gravity F = mg is directly related to the local gravitational acceleration g , and the difference in gravitational acceleration in different regions will introduce additional errors, which need to be partially offset through complex measurement and correction, further reducing the accuracy of force value transfer. Chinese invention patent CN104764555B discloses a fully automatic piston pressure gauge, which uses a bob instead of a traditional weight to avoid pressure deformation of the piston due to swinging, thereby achieving stable pressure output. Secondly, Chinese invention patent CN120333698A discloses an automatic piston pressure gauge system and its calibration method, which uses a combined weight automatic loading scheme to achieve fine adjustment of pressure compared to the traditional manual batch addition of weights. However, both of these schemes still rely on the "mass-gravity" force value generation logic, and cannot completely eliminate the influence of gravitational acceleration and environmental factors on force value accuracy. Moreover, the mechanical positioning error of the bob and the stacking error of the combined weight still restrict the overall precision improvement.

[0004] ​Secondly, the pressure output flexibility and the calibration comprehensiveness are insufficient. The pressure output of the traditional piston pressure gauge completely depends on the fixed mass of the weight, and only a limited fixed pressure point can be generated. If the pressure point needs to be subdivided or cover different ranges, the equipment needs to be disassembled and the weight set needs to be replaced, which is cumbersome and easy to damage the equipment. In the existing improved scheme, the movable weight design realizes the subdivision adjustment of the pressure point, but it depends on the precise mechanical transmission structure, and the cumulative error control is difficult. Moreover, the range expansion needs to adjust the weight and torque ratio of the movable weight simultaneously, and the flexibility is limited. The automatic loading scheme of the combined weight realizes the fine adjustment of the pressure through binary combination, but it still depends on the physical mass of the weight. The force value accuracy is restricted by the weight processing error, wear and other factors. Moreover, the collaborative error caused by the combination of multiple weights further affects the stability of the pressure output.

[0005] Thirdly, the automation and digitalization degree are not suitable. The weight loading, pressure regulation and data reading of the traditional piston pressure gauge all depend on manual operation, which not only has high labor intensity, but also introduces human error due to the difference in skill and technique of the operator, resulting in poor repeatability of the measurement results. Although some existing automatic pressure gauges realize the automation of part of the process, they lack a digital control system matched with high-precision force value sensing. The data transmission, error correction and process control are still at the semi-automation level, which cannot meet the development needs of modern measurement field.

[0006] In addition, the modern measurement field is developing rapidly towards digitalization and automation. The traditional piston pressure gauge based on pure physical principle and mechanical structure cannot meet the needs of high-efficiency calibration, remote control and data integration of the measurement system. SUMMARY

[0007] The first object of the present application is to provide a digital piston pressure gauge system with stable pressure output, high precision and digital control.

[0008] Another object of the present application is to provide a measurement method for the verification and calibration of the digital piston pressure gauge system.

[0009] The first technical solution adopted by the present application is a digital piston pressure gauge system, which comprises a piston system, a force value sensing assembly, a positioning system, a pressure medium circulation system and a control unit. The piston system comprises a piston rod and a piston cylinder. The piston rod is vertically arranged in the piston cylinder and gap-fitted with the piston cylinder. The top of the piston rod is fixed with a rotating disc, and the center of the rotating disc is placed with a conductive steel ball. The force value sensing assembly comprises a high-precision force value sensor arranged vertically. The upper loading end of the high-precision force value sensor is fixedly connected with the bracket of the positioning system, and the lower loading end is in point contact with the top of the conductive steel ball. A medium interface is formed in the side wall of the piston cylinder, and the medium interface is in communication with the output end of the pressure medium circulation system. The control unit is electrically connected to the high-precision force sensor and the drive control terminal of the pressure medium circulation system.

[0010] The invention is further characterized by: The piston system can be a single-stage or multi-stage structure; In a single-stage piston system, the piston rod is a cylindrical structure with a consistent diameter along the axial direction. The outer circumferential surface of the piston rod is adapted to the inner circumferential surface of the piston cylinder, and the two work together to form a fixed annular effective piston area. In a multi-stage piston system, the piston rod is a stepped cylindrical structure with a diameter that varies along the axial direction. The stepped cylindrical structure includes at least two cylindrical segments with different diameters. The outer circumferential surface of each cylindrical segment is adapted to the inner circumferential surface of the piston cylinder. The cylindrical segments with different diameters are matched with the piston cylinder to form multiple annular effective piston areas with different values.

[0011] A recess is provided at the center of the upper surface of the rotating disk, and the conductive steel ball is placed in the recess and makes point contact with it; the lower loading end of the high-precision force sensor is provided with a recess that is compatible with the conductive steel ball.

[0012] The positioning system includes an inverted U-shaped bracket; The middle of the horizontal beam of the inverted U-shaped bracket is fixedly connected to the upper loading end of the high-precision force sensor; a piston position indicator is fixedly installed below the horizontal beam of the inverted U-shaped bracket and above the corresponding rotating disk. The piston position indicator is a non-contact displacement sensor, and its detection end is vertically downward facing the upper surface of the rotating disk; the signal output end of the piston position indicator is electrically connected to the control unit. If the piston system is a single-stage structure, the lower ends of the two vertical support legs of the inverted U-shaped bracket are fixedly connected to the piston base; if the piston system is a multi-stage structure, both vertical support legs of the inverted U-shaped bracket are connected to the positioning drive unit, and the positioning drive unit is driven by the vertical support legs of the inverted U-shaped bracket to drive the inverted U-shaped bracket to move up and down in the vertical direction. The control input end of the positioning drive unit is electrically connected to the control unit.

[0013] It also includes piston motors; Several rotating contacts are uniformly fixed along the circumferential direction on the outer periphery of the rotating disk, and the extension direction of each rotating contact is consistent with the radial direction of the rotating disk. The piston motor has a drive block at the output shaft end that is adapted to the rotating contact. The contact surface between the drive block and the rotating contact is an arc-shaped transition surface. The piston motor is electrically connected to the control unit.

[0014] The pressure medium circulation system includes a medium container, a pressure relief valve, and a pressure regulating unit; The outlet of the medium container is communicated with one end of the pressure relief valve through a connecting pipeline, and the other end of the pressure relief valve is communicated with the medium interface of the piston cylinder through a connecting pipeline, and the pressure regulating unit is connected in series in the connecting pipeline between the pressure relief valve and the piston cylinder. The pressure relief valve is an electromagnetic pressure relief valve, and the control end thereof is electrically connected with the control unit.

[0015] The pressure output system comprises a stop valve and a pressure measuring port. The side wall of the piston cylinder is provided with at least one output interface, the output interface is sealingly and fixedly connected with one end of the pressure measuring port, and the stop valve is connected in series in the connecting channel between the output interface and the pressure measuring port. The stop valve is an electromagnetic stop valve, and the control end thereof is electrically connected with the control unit.

[0016] Another technical solution adopted by the present application is a measurement method for the verification and calibration of the digital piston pressure gauge system, comprising the following steps: Step 1, install the pressure instrument to be calibrated in the pressure measuring port, and open the stop valve through the control unit; Step 2, input the target pressure value and the verification and calibration error determination standard through the control unit; Step 3, the control unit determines whether the piston system can be measured according to the input target pressure value, and if yes, proceeds to step 4, and if not, issues a warning and ends; Step 4, the control unit controls the pressure relief valve to open, the pressure regulating unit is adjusted to the corresponding capacity, after the medium container injects the medium into the system, the pressure relief valve is closed, and the pressure regulating unit starts to generate pressure; Step 5, during the pressure generation process, the piston motor drives the rotating disc of the piston rod to continuously rotate, the piston position indicator feeds back the position state, and the high-precision force value sensor feeds back the force value in real time F , the control unit controls the pressure regulating unit to increase or decrease the pressure according to the feedback signal, until the force value F reaches the target force value corresponding to the set pressure, and the adjustment is stopped; Step 6, read the actual pressure of the pressure instrument to be calibrated, and judge whether the error between the actual pressure and the target pressure value meets the set verification and calibration standard.

[0017] The feature of the other technical solution of the present application is also: In step 3, the control unit determines the range coverage capability according to the formula P = F / S , wherein F is the force value corresponding to the measurement range of the high-precision force value sensor, S is the effective piston area of the piston system; when the maximum value of the target pressure P does not exceed F , the maximum value of SThe ratio of the minimum value and the target pressure P The test is considered measurable when the minimum value is not lower than the initial pressure; where the initial pressure = (mass of the combined piston rod + mass of the conductive steel ball) × g / S , g This is the acceleration due to gravity.

[0018] In step 5, when the control unit detects that the rotation speed of the rotating disk is lower than the set threshold, the piston motor drives the drive block to approach the rotating disk, so that the drive block contacts any rotating contact and pushes the rotating disk to rotate. After the rotation speed of the rotating disk reaches the set threshold, the piston motor drives the drive block to reset and separate from the rotating contact.

[0019] The beneficial effects of this invention are: 1. This invention employs a high-precision force sensor with a comprehensive accuracy of 0.0005% (parts per million) to replace traditional standard weights as the core force source. This accuracy significantly surpasses the national metrological regulations' requirement of 0.001% error for the highest-grade non-reference weights. Simultaneously, the force sensor directly senses the force signal, eliminating the need for a "mass-gravity" conversion process. This completely eliminates the interference of differences in gravitational acceleration across different regions and environmental factors such as temperature and humidity on force accuracy, overcoming the technical bottleneck of limited force source accuracy in traditional piston-type pressure gauges and providing a core guarantee for pressure output accuracy. Furthermore, relying on the wide-range sensing capability of the high-precision force sensor and the fine adjustment function of the pressure regulation unit, combined with a fixed initial mass (… M 活塞杆 + M 传导钢珠 ) and piston effective area S It can achieve accurate output of all pressure points within the measurement range, starting pressure point. P 0 = ( M 活塞杆 + M 传导钢珠 (×g / S, highest pressure point) P max = ( F max +( M 活塞杆 + M 传导钢珠 (×g) / S, breaking through the limitation of traditional piston pressure gauges that can only measure fixed pressure points corresponding to weights, and meeting the needs of fine-grained pressure point calibration and continuous range coverage.

[0020] 2. The system of the present application constructs a full-process automatic control system, the control unit is connected with a high-precision force value sensor, a positioning driving unit, a pressure medium circulating system and a pressure output system, realizes full-process automatic execution of parameter input, range determination, medium injection, pressure regulation, data acquisition and error calculation, and does not need manual intervention for cumbersome operations such as weight loading and pressure regulation, thereby reducing labor intensity, avoiding human errors introduced by operation personnel proficiency and skill differences, and improving repeatability and consistency of measurement results.

[0021] Further, the piston system of the system of the present application supports single-stage and multi-stage structures, the multi-stage structure can quickly switch a plurality of different effective piston areas through a stepped piston rod, without disassembling the equipment, so as to cover multi-range pressure transmission requirements; in cooperation with a wide measurement range of the high-precision force value sensor and a fine adjustment capability of the pressure regulation unit, a continuous adjustable pressure point can be generated, instead of a limited fixed pressure point in a traditional scheme, thereby meeting conventional range requirements and adapting to high-precision scenes of subdivided pressure points. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic diagram of the device of the present application; Figure 2 is a piston system schematic diagram of embodiment 1 of the present application; Figure 3 is a piston system schematic diagram of embodiment 2 of the present application.

[0023] In the figure: 1, piston rod, 2, piston cylinder, 3, conductive steel ball, 4, high-precision force value sensor, 5, bracket, 6, positioning driving unit, 7, piston motor, 8, rotating contact, 9, medium container, 10, pressure relief valve, 11, pressure regulation unit, 12, stop valve, 13, pressure measuring port, 14, pressure-bearing pipeline, 15, control unit, 16, piston position indicator. DETAILED DESCRIPTION

[0024] The present application will be described in detail below in combination with the drawings and specific embodiments.

[0025] Embodiment 1 The digital piston type pressure gauge system provided in the embodiment includes a piston system, a force value sensor assembly, a positioning system, a pressure medium circulating system, a pressure output system and a control unit 15, as shown in Figure 1 .

[0026] The piston system comprises a piston rod 1 and a piston cylinder 2, the piston rod 1 is vertically arranged in the piston cylinder 2 and is in clearance fit, the top of the piston rod 1 is coaxially fixedly connected with a circular rotating disc, the rotating disc coincides with the axis of the piston rod 1, and the force value transmission is ensured without deviation; the center of the upper surface of the rotating disc is provided with a conductive steel ball 3, and a point contact support structure is formed, so that lateral deviation is avoided in the force value transmission process. Figure 2 As shown in the figure, the piston rod 1 of the embodiment is a cylindrical structure with a diameter consistent along the axial direction, the outer periphery of the piston rod is matched with the inner periphery of the piston cylinder, and the two are matched to form a fixed annular effective piston area.

[0027] The core of the force value sensing assembly is a high-precision force value sensor 4, the precision of the high-precision force value sensor 4 is determined according to the precision of the pressure instrument to be calibrated, and the comprehensive precision can reach 0.0005%, which is significantly better than the error requirement of 0.001% of the highest grade non-reference weight in the national measurement regulation, and there is no need to go through the "mass-gravity" conversion process, and the interference of gravity acceleration and environmental factors on the force value precision is completely eliminated. The high-precision force value sensor 4 is vertically arranged, the lower loading end is in stable point contact with the top of the conductive steel ball 3, and the force value is accurately transmitted along the axial direction; the upper loading end of the high-precision force value sensor 4 is fixedly connected with the bracket 5 of the positioning system, and a rigid hard connection structure is formed, so that additional errors are avoided in the force value transmission process due to loose connection.

[0028] The positioning system comprises an inverted U-shaped bracket 5, the two vertical legs of the inverted U-shaped bracket 5 are fixedly connected with the equipment base at the lower end, a portal support structure is formed, and the middle part of the horizontal beam is fixedly connected with the upper loading end of the high-precision force value sensor 4 through bolts, so that the verticality and stability of the sensor after installation are ensured. The piston position indicator 16 is fixedly installed below the horizontal beam of the inverted U-shaped bracket 5 and above the rotating disc, the piston position indicator 16 is a non-contact displacement sensor, the detection end thereof is vertically downward towards the upper surface of the rotating disc, the axial height position of the rotating disc can be detected in real time, and the position signal is transmitted to the control unit 15 through a cable, so that the position feedback basis is provided for pressure regulation.

[0029] The pressure medium circulation system comprises a medium container 9, a pressure relief valve 10, a pressure regulating unit 11 and a pressure-bearing pipeline 14, the medium container 9 is used for storing pressure transmission medium, the outlet thereof is communicated with one end of the pressure relief valve 10 through the pressure-bearing pipeline 14, the other end of the pressure relief valve 10 is sealingly connected with the medium interface of the side wall of the piston cylinder 2 through the pressure-bearing pipeline 14, and the pressure regulating unit 11 is connected in series on the pressure-bearing pipeline 14 between the pressure relief valve 10 and the piston cylinder 2. The pressure relief valve 10 is an electromagnetic pressure relief valve, the control end thereof is electrically connected with the control unit 15, the opening and closing state of the pressure relief valve 10 is controlled by the control unit 15, and the injection and backflow control of the medium is realized.

[0030] The pressure regulating unit 11 is composed of a servo motor, a ball screw and an adjustable cavity, the adjustable cavity is provided with a sealing piston, the sealing piston is synchronously linked with the ball screw, the servo motor drives the ball screw to rotate, the sealing piston is driven to move along the adjustable cavity in the axial direction, the volume of the adjustable cavity is finely adjusted, and then the pressure in the piston system is controlled.

[0031] The pressure output system includes a stop valve 12 and a pressure measuring port 13, the side wall of the piston cylinder 2 is provided with an output interface, the output interface is sealingly and fixedly connected with one end of the pressure measuring port 13, and the stop valve 12 is connected in series in the connecting channel between the output interface and the pressure measuring port 13. The pressure measuring port 13 adopts a standard threaded interface, an annular sealing groove is formed in the inner wall of the pressure measuring port 13, a high-pressure sealing gasket is arranged in the groove, and reliable sealing cooperation can be formed with the connecting end of the pressure instrument to be calibrated, so that pressure leakage is prevented; the stop valve 12 is an electromagnetic stop valve, the control end of the stop valve 12 is electrically connected with the control unit 15, the stop valve 12 is controlled to be turned on or turned off by the control unit 15, and the pressure output and closing of the pressure measuring port 13 are realized.

[0032] The control unit 15 is electrically connected with the signal output end of the high-precision force value sensor 4, the positioning driving unit 6 of the positioning system, the servo motor and the pressure relief valve 10 of the pressure medium circulating system and the stop valve 12 of the pressure output system through signal cables, so as to realize signal transmission and instruction issuing. The control unit 15 is provided with a piston area parameter, a starting mass parameter (the sum of the mass of the piston rod 1 and the mass of the conductive steel ball 3) and a pressure-force value conversion program, can receive the real-time force value signal fed back by the high-precision force value sensor 4 and the position signal fed back by the piston position indicator, calculates and controls the actions of each executing component through the built-in program, and ensures that the system outputs stable and accurate standard pressure.

[0033] Embodiment 2 The digital piston pressure gauge system provided in the embodiment is like Figure 3As shown, the piston system adopts a stepped cylindrical piston rod 1, which is provided with at least two cylindrical segments with different diameters in the axial direction, and the outer periphery of each cylindrical segment is accurately matched with the inner periphery of the piston cylinder 2. By switching the matching state of the cylindrical segments with different diameters with the piston cylinder 2, a plurality of annular effective piston areas with different values can be formed, and the multi-range pressure calibration requirement can be covered without disassembling the components. The two vertical legs of the inverted U-shaped support 5 are fixed at the lower end of the equipment base, and the horizontal beam is fixedly connected with the upper loading end of the high-precision force value sensor 4. The two vertical legs of the inverted U-shaped support 5 are in transmission connection with the positioning driving unit 6, and a guide rail structure is arranged outside the vertical legs. The positioning driving unit 6 can drive the inverted U-shaped support to stably ascend and descend along the guide rail, thereby driving the high-precision force value sensor to move synchronously, and realizing the switching of the different cylindrical segments of the piston rod with the piston cylinder. The non-contact piston position indicator 16 is fixedly installed below the horizontal beam of the inverted U-shaped support, and the detection end is vertically directed to the upper surface of the rotating disc. The rotating disc height position is fed back in real time and transmitted to the control unit 15, so as to ensure that the piston is always in the stable working interval.

[0034] In the pressure output system, a plurality of output interfaces are uniformly arranged on the side wall of the piston cylinder 2 in the circumferential direction. Each output interface is sealingly and fixedly connected with a pressure measuring port 13 through a pressure bearing pipeline 14, and a stop valve 12 is connected in series on each connection channel. The pressure measuring port 13 adopts a standard threaded interface, a flange interface and a quick connector interface, which are adapted to different types of pressure instruments to be calibrated. The control end of each stop valve 12 is electrically connected with the control unit 15, so as to individually control the on-off of the corresponding pressure measuring port, and support the simultaneous calibration of multiple pressure instruments.

[0035] The force value sensing assembly, the pressure medium circulating system, the pressure output system and the control unit of the embodiment are consistent with those of embodiment 1.

[0036] Embodiment 3 Based on embodiment 1 or 2, the digital piston pressure gauge system provided in the embodiment, in the pressure output system, a plurality of output interfaces are uniformly arranged on the side wall of the piston cylinder 2 in the circumferential direction. Each output interface is sealingly and fixedly connected with a pressure measuring port 13 through a pressure bearing pipeline 14, and a stop valve 12 is connected in series on each connection channel. The pressure measuring port 13 adopts a standard threaded interface, a flange interface and a quick connector interface, which are adapted to different types of pressure instruments to be calibrated. The control end of each stop valve 12 is electrically connected with the control unit 15, so as to individually control the on-off of the corresponding pressure measuring port, and support the simultaneous calibration of multiple pressure instruments.

[0037] Embodiment 4 On the basis of embodiment 1 or 2, the digital piston pressure gauge system provided by the embodiment has a semispherical pit in the center of the upper surface of the rotating disc, the pit is sized to fit the conductive steel ball 3, and the conductive steel ball 3 is placed in the pit to form a stable point contact support structure, thereby avoiding lateral deviation during force value transmission.

[0038] The lower loading end of the high-precision force value sensor 4 is provided with a semispherical positioning pit sized to fit the conductive steel ball 3, and the top of the conductive steel ball 3 is embedded in the positioning pit to form a stable point contact with the high-precision force value sensor 4, thereby ensuring accurate axial transmission of the force value.

[0039] Embodiment 5 On the basis of embodiment 4, the digital piston pressure gauge system provided by the embodiment has a plurality of strip-shaped rotating contacts 8 fixedly arranged on the outer periphery of the rotating disc in the circumferential direction, the extension direction of each rotating contact 8 is consistent with the radial direction of the rotating disc, and the outer end surface is flush, thereby ensuring uniform stress. The inverted U-shaped support 5 of the positioning system is fixedly installed with a piston motor 7 on one side through a support plate, the output shaft end of the piston motor 7 is provided with a driving nub with an arc-shaped transition surface, the contact surface of the driving nub is sized to fit the outer end surface of the rotating contact 8, thereby avoiding lateral force interference when the contact surface of the driving nub contacts the outer end surface of the rotating contact 8. The piston motor 7 is electrically connected with the control unit 15, when the control unit 15 detects that the rotating speed of the rotating disc is lower than a set threshold, the piston motor 7 drives the driving nub to approach the rotating disc, contacts any rotating contact 8 and pushes the rotating disc to rotate, after the rotating speed reaches the set threshold, the driving nub is reset to separate from the rotating contact 8, thereby maintaining the free rotation state of the rotating disc, ensuring that a stable medium oil film is formed between the piston rod 1 and the piston cylinder 2, and eliminating friction interference.

[0040] In the embodiment, the inverted U-shaped support 5 is still fixedly installed with a piston position indicator 16 below the horizontal crossbeam, the detection end of the piston position indicator 16 vertically downwardly faces the upper surface of the rotating disc, detects the axial height position of the rotating disc in real time and transmits the signal to the control unit 15, and the driving of the piston motor 7 together ensures that the piston system not only maintains a stable rotating speed but also is in an optimal working position. The lower loading end positioning pit of the high-precision force value sensor 4 maintains point contact with the conductive steel ball 3, the force value transmission is not affected by the rotation of the rotating disc, and the high measurement accuracy of 0.0005% can still be maintained. The medium container 9, the pressure relief valve 10 and the pressure regulating unit 11 of the pressure medium circulating system are in sealed communication with the piston cylinder 2 through the pressure-bearing pipeline 14, the control unit 15 receives the feedback signals of the high-precision force value sensor 4 and the piston position indicator 16, synchronously controls the actions of the pressure regulating unit 11 and the piston motor 7, realizes the double guarantee of accurate pressure output and stable rotation of the rotating disc, further improves the repeatability and accuracy of system calibration, and is suitable for high-precision measurement calibration scenes in laboratories.

[0041] Embodiment 6 The embodiment provides a measurement method for verification and calibration of a digital piston pressure gauge system, comprising the following steps: Step 1, install the pressure instrument to be calibrated on the pressure measuring port 13, and open the stop valve 12 through the control unit 15; Step 2, input the target pressure value and the verification and calibration error determination standard through the control unit 15; According to the formula P = F / S Determine the range coverage capability (wherein F is the force value corresponding to the measurement range of the high-precision force value sensor 4, S is the effective piston area of the piston system) Step 3, the control unit 15 determines whether the piston system can be measured according to the input target pressure value, and if yes, proceed to step 4, and if not, issue a warning and end; Specifically, the control unit 15 will determine whether the current piston system can cover the target range according to the formula P = F / S (wherein F is the measurement range of the high-precision force value sensor 4, and S is the effective piston area), combined with the input pressure range upper limit. For single-stage piston structure, the maximum force value required to calculate the range upper limit F max = P max × S , if F max is within the measurement range of the high-precision force value sensor 4 and is not less than the force value generated by the starting mass ( M 活塞杆 + M 传导钢珠 ) × g (g is the standard gravity acceleration, and the built-in program is a fixed value), it is determined that it can be measured, otherwise, output the range overrun warning and terminate the process; for multi-stage piston structure, the control unit 15 will traverse all levels of piston area S1, S2, …, S n , respectively calculate the corresponding maximum force value, select the piston area that meets the force value range requirement, and preferentially select the piston area that makes the maximum force value in the middle of the sensor range to improve the measurement accuracy, and if there is no piston area that meets the condition, output a warning. If it is a multi-stage piston structure, the control unit 15 will send instructions to the positioning driving unit 6 to drive the inverted U-shaped support 5 to move up and down along the vertical direction, drive the high-precision force value sensor 4 to move synchronously, make the selected piston cylinder segment and the piston cylinder 2 accurately cooperate, and form the target effective piston area; the piston position indicator 16 will feedback the height position of the rotating disc in real time, and the control unit 15 will fine-tune the positioning driving unit 6 according to the feedback signal to ensure that the piston is in the best working position; Step 4, the control unit 15 controls the pressure relief valve 10 to open, and controls the pressure regulating unit 11 to adjust to the corresponding capacity, the medium in the medium container 9 is injected into the piston system through the pressure pipeline 14, and when the system is filled with the medium and the pressure tends to be balanced, the piston position indicator 16 feeds back the initial position signal of the rotating disc, and the control unit 15 immediately closes the pressure relief valve 10, so that the medium container 9 is disconnected from the piston system; Step 5, the control unit 15 controls the pressure regulating unit 11 to start pressure building, and the piston motor 7 drives the rotating disc to continuously rotate, and the piston position indicator 16 feeds back the height of the rotating disc in real time, and the high-precision force sensor 4 feeds back the force value in real time F , the control unit 15 controls the pressure regulating unit 11 to increase or decrease the pressure according to the feedback signal, until the force value F reaches the target force value corresponding to the set pressure, and the adjustment is stopped; Specifically, the control unit 15 starts the piston motor 7, drives the contact block to contact the rotating contact 8 on the outer periphery of the rotating disc, and drives the rotating disc to rotate the piston rod 1; after the rotating speed reaches a set threshold value (to ensure that a stable medium oil film is formed between the piston and the piston cylinder 2), the contact block is separated from the rotating contact 8, and the piston rod 1 remains in a free rotating state. At the same time, the control unit 15 controls the pressure regulating unit 11 to fine-tune the volume of the adjustable volume chamber according to the initial force value M 活塞杆 + M 传导钢珠 )×g and the target initial pressure P 0 = ( M 活塞杆 + M 传导钢珠 )×g / S, to preliminarily establish the system pressure, and the high-precision force sensor 4 feeds back the force value signal in real time, until the force value is stable around the initial force value.

[0042] After the initial pressure is adjusted and stabilized, the control unit 15 controls each pressure point according to the set target pressure value (which can also be a sequence of pressure points). First, the target force value P i required at the current pressure point F i = P i × S + (M piston rod + M conductive steel ball) × g is calculated. The high-precision force sensor 4 collects the current force value F real in real time and transmits the signal to the control unit 15, and the control unit 15 compares F realWith F i , if F real < F i , the pressure regulating unit 11 controls the adjustable volume to reduce the volume to increase the system pressure; if F real > F i , the pressure regulating unit 11 controls the adjustable volume to increase the volume to reduce the system pressure. During the adjustment process, the piston position indicator 16 continuously feeds back the position of the rotating disc, and if the position is below the set range, the control unit 15 will simultaneously increase the pressure regulating range to ensure that the piston is always in the working position and keeps stable rotation. Stop adjusting when reaching the set point.

[0043] Step 6, read the actual pressure of the calibrated pressure instrument, and judge whether the error between the actual pressure and the target pressure value meets the set verification and calibration standard.

[0044] Step 7, after all the detection is completed, the control unit 15 controls the pressure regulating unit 11 to adjust to the initial position and then opens the pressure relief valve 10, the control unit 15 controls the pressure regulating unit 11 to restore the position before starting, the medium enters the medium container 9, and the control unit 15 controls to close the pressure relief valve 10.

[0045] The present application replaces the traditional weight with a high-precision force value sensor 4 as the force value source, point contact force value transmission and automatic closed-loop control, not only greatly improves the force value transmission accuracy, but also avoids the interference of factors such as gravitational acceleration and human operation, the pressure output is stable, the error is small, and the high-precision verification and calibration requirements of the range pressure instrument in the conventional industrial scene can be met.

Claims

1. A digitalizing piston gauge system, characterized by, The piston system, the force value sensing assembly, the positioning system, the pressure medium circulating system and the control unit are included. The piston system includes a piston rod and a piston cylinder, the piston rod is vertically arranged in the piston cylinder and gap-fitted with the piston cylinder, the top of the piston rod is fixed with a rotating disc, and the center of the rotating disc is placed with a conductive steel ball. The force value sensing assembly includes a high-precision force value sensor arranged vertically, the upper loading end of the high-precision force value sensor is fixedly connected with the support of the positioning system, and the lower loading end is point-contacted with the top of the conductive steel ball. The sidewall of the piston cylinder is provided with a medium interface, and the medium interface is in communication with the output end of the pressure medium circulating system. The control unit is electrically connected with the high-precision force value sensor and the drive control end of the pressure medium circulating system.

2. The digitized piston gauge system of claim 1, wherein, The piston system is single-stage structure or multi-stage structure. In the single-stage structure of the piston system, the piston rod is a cylindrical structure with a consistent diameter along the axial direction, the outer peripheral surface of the piston rod is adapted with the inner peripheral surface of the piston cylinder, and the two are cooperated to form a fixed annular effective piston area. In the multi-stage structure of the piston system, the piston rod is a stepped cylindrical structure with a segmented diameter change along the axial direction, the stepped cylindrical structure includes at least two cylindrical segments with different diameters, the outer peripheral surface of each cylindrical segment is respectively adapted with the inner peripheral surface of the piston cylinder, the cylindrical segments with different diameters are correspondingly cooperated with the piston cylinder to form a plurality of annular effective piston areas with different values.

3. The digitizing piston gauge system of claim 1 or 2, wherein, The upper surface of the rotating disc is provided with a pit in the center, the conductive steel ball is placed in the pit and is point-contacted therewith, and the lower loading end of the high-precision force value sensor is provided with a pit adapted with the conductive steel ball.

4. The digitizing piston gauge system of claim 3, wherein, The positioning system includes an inverted U-shaped support. The middle part of the horizontal crossbeam of the inverted U-shaped support is fixedly connected with the upper loading end of the high-precision force value sensor, a piston position indicator is fixedly installed below the horizontal crossbeam of the inverted U-shaped support and above the rotating disc, the piston position indicator is a non-contact displacement sensor, the detection end of the piston position indicator is vertically downward toward the upper surface of the rotating disc, and the signal output end of the piston position indicator is electrically connected with the control unit. If the piston system is single-stage structure, the lower ends of the two vertical legs of the inverted U-shaped support are fixedly connected with the piston base, if the piston system is multi-stage structure, the two vertical legs of the inverted U-shaped support are connected with a positioning drive unit, the positioning drive unit is in transmission connection with the vertical legs of the inverted U-shaped support and is used for driving the inverted U-shaped support to ascend and descend along the vertical direction, and the control input end of the positioning drive unit is electrically connected with the control unit.

5. The digitizing piston gauge system of claim 4, wherein, A piston motor is further included. The outer periphery of the rotating disc is uniformly fixed with a plurality of rotating contacts in the circumferential direction, and the extension direction of each rotating contact is consistent with the radial direction of the rotating disc. The output shaft end of the piston motor is provided with a driving nub adapted with the rotating contact, the contact surface between the driving nub and the rotating contact is an arc transition surface, and the piston motor is electrically connected with the control unit.

6. The digitizing piston gauge system of claim 5, wherein, The pressure medium circulating system includes a medium container, a pressure relief valve and a pressure regulating unit. The outlet of the medium container is in communication with one end of the pressure relief valve through a connecting pipeline, the other end of the pressure relief valve is in communication with the medium interface of the piston cylinder through a connecting pipeline, and the pressure regulating unit is connected in series on the connecting pipeline between the pressure relief valve and the piston cylinder. The pressure relief valve is an electromagnetic pressure relief valve, and the control end thereof is electrically connected with the control unit.

7. The digitizing piston gauge system of claim 6, wherein, The pressure output system comprises a stop valve and a pressure tap; The side wall of the piston cylinder is provided with at least one output interface, the output interface is sealingly and fixedly connected with one end of the pressure tap, and the stop valve is connected in series on a connecting channel between the output interface and the pressure tap. The stop valve is an electromagnetic stop valve, and the control end of the stop valve is electrically connected with the control unit.

8. Method of measurement for the verification and calibration of a digital piston gauge system, characterized in that, The method comprises the following steps: Step 1, install the pressure instrument to be calibrated on the pressure tap, and open the stop valve through the control unit; Step 2, input the target pressure value and the calibration error determination standard through the control unit; Step 3, the control unit determines whether the piston system can be measured according to the input target pressure value, if yes, proceed to step 4, if no, issue a warning and end; Step 4, the control unit controls the pressure relief valve to be opened, the pressure adjusting unit is adjusted to the corresponding capacity, after the medium container injects the medium into the system, the pressure relief valve is closed, and the pressure adjusting unit starts to generate pressure; Step 5, during the pressure building process, the piston motor drives the rotating disc of the piston rod to continue rotating, the piston position indicator feeds back the position state, and the high-precision force value sensor feeds back the force value in real time F The control unit controls the pressure regulating unit to increase or decrease the pressure according to the feedback signals until the force value reaches the target force value corresponding to the set pressure, and the adjustment is stopped F ; Step 6, read the actual pressure of the pressure instrument to be calibrated, and determine whether the error between the actual pressure and the target pressure value meets the set calibration standard.

9. The method of measurement for the verification and calibration of the operation of a digitized piston gauge system according to claim 8, characterized in that, In step 3, the control unit determines the range coverage capability according to the formula P = F / S , wherein F is the force value corresponding to the measurement range of the high-precision force value sensor, S is the effective piston area of the piston system; when the maximum value of the target pressure P does not exceed F , the ratio of the maximum value of S to the minimum value of P , and the minimum value of the target pressure g is not lower than the starting pressure, it is determined to be measurable; wherein the starting pressure = (combined piston rod mass + conducting steel ball mass) x S / g , g is the acceleration due to gravity.

10. The method of claim 8, wherein: In step 5, when the control unit detects that the rotating speed of the rotating disc is lower than the set threshold value, the piston motor drives the driving block to approach the rotating disc, so that the driving block is in contact with any rotating contact and drives the rotating disc to rotate, and after the rotating speed of the rotating disc reaches the set threshold value, the piston motor drives the driving block to reset and separate from the rotating contact.

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