A piston pressure gauge calibration method based on magnetic balance principle

Abstract

The piston pressure gauge calibration method based on the magnetic balance principle of the present invention is based on the electromagnetic force balance principle. Through the characteristics of equal and opposite repulsive forces of the magnetic field, the gravity of the weights originally used for balancing is replaced by a balance or other standard device, without manual addition and subtraction of weights, and the balancing force is directly weighed by the balance. By comprehensively adopting the feedback signal of the laser position sensor, an automatic calibration auxiliary balancing device is designed, and the process of manually adjusting the balance of the calibration system in the traditional method is abandoned. The accuracy of calibration is greatly increased. Through the electromagnetic balance principle, the process of manually placing weights to achieve balance is transformed into a process in which the balance continuously reads the force value in real time to finally achieve balance, so that the key parameter balance quality data is automatically obtained, the automation degree of the calibration method is improved, and the method of the present invention is more in line with the new version of the verification regulations, and a higher quality piston pressure gauge calibration is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of measurement and detection, and in particular to a piston pressure gauge calibration method based on the magnetic balance principle. Background Art

[0002] The piston pressure gauge is an instrument for pressure measurement based on fluid static balance and Pascal's law. Its principle is very close to the pressure definition model, with high accuracy and good stability. It is mainly used as a pressure standard in the measurement room, laboratory or production science experiment link, and can also be used to monitor the measurement performance of other high-precision instruments.

[0003] The existing piston pressure gauge is an important standard device for realizing and transmitting pressure values. The core component of the piston pressure gauge is the piston system composed of a piston rod and a piston cylinder. In a gravity field, a certain mass of weight is loaded on the piston system with a known area to measure the pressure of the fluid medium. It is widely used in national standard devices and transmission standards in international comparisons.

[0004] At present, in my country's pressure measurement value transmission system, the establishment of (-0.1~250)MPa pressure measurement benchmark and measurement standard is based on piston pressure gauge as the main reference (standard) instrument. Almost all pressure measurement instruments are traceable to 0.002 or 0.005 grade piston pressure gauge. The establishment and maintenance of the pressure value traceability system depends to a large extent on the progress of piston pressure gauge technology and the development of piston pressure gauge verification technology.

[0005] The calibration of the piston pressure gauge is to determine the effective area of ​​the piston pressure gauge to be calibrated by using a standard piston pressure gauge. The existing piston pressure gauge calibration method repeatedly adjusts the loading amount of the small weight at the measured end and manually determines whether the calibration system reaches a balanced state, thereby ensuring that the two piston pressure gauges produce the same pressure according to Pascal's theorem.

[0006] The calibration process of the prior art requires manual judgment of the verticality of the piston through a level, and judgment of the piston descent speed through a displacement sensor system based on the eddy current principle, and then judgment of the system balance point through devices such as a piston position indicator and a differential pressure indicator; this calibration method of the prior art manually adjusts the standard end and the measured end piston loading mass by manually adding or subtracting gram group (milligram group) weights, and then judges the system balance point through devices such as a piston position indicator and a differential pressure indicator; the calibration process requires continuous adjustment of the milligram group weight counterweight, repeated pressurization, and fixed-point balance; and after many attempts and waiting, the balance of the calibration point can be finally achieved; the uncertainty caused by human factors in the calibration process is large, the calibration system adjustment balance process is cumbersome, time-consuming and labor-intensive, and the entire calibration method relies on manpower to complete, with a low degree of automation;

[0007] And with the release and implementation of the new version of JJG 59-2022 Piston Pressure Gauge Verification Procedure, the procedure requires the actual measurement of deformation coefficients for piston pressure gauges above 6MPa, and puts forward higher requirements on the quality of piston pressure gauge calibration, which also significantly increases the workload of calibration. The existing technology has a low degree of automation, is greatly affected by human factors, and brings about more gross errors and random errors, and the calibration work has a low degree of automation;

[0008] Therefore, those skilled in the art are committed to developing a piston pressure gauge calibration method based on the magnetic balance principle, aiming to solve the defects in the prior art. Summary of the invention

[0009] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is that in the current prior art, it is necessary to manually judge the verticality of the piston through a spirit level, and to judge the piston descending speed through a displacement sensor system based on the eddy current principle, and then to judge the system balance point through devices such as a piston position indicator and a differential pressure indicator; the uncertainty caused by human factors in the calibration process is large, the calibration system balance adjustment process is cumbersome, time-consuming and labor-intensive, the entire calibration method relies on manpower to complete, and the degree of automation is low.

[0010] To achieve the above object, the present invention provides a piston pressure gauge calibration method based on the magnetic balance principle, comprising the following steps:

[0011] Step 1: Build a piston pressure gauge calibration system;

[0012] Step 2: Press the standard piston and the piston to be calibrated up, and record the values ​​after they reach the initial equilibrium state;

[0013] Step 3: Add a certain amount of weight to the standard piston and the piston to be calibrated, and record the value after the second balance;

[0014] Step 4, performing relevant calculations based on the data measured in steps 2 and 3 to calibrate the piston to be calibrated;

[0015] The piston pressure gauge calibration system constructed in step 1 includes a laser position sensor, a configuration weight, an electronic balance, a neodymium iron boron magnet, a kilogram weight, a piston pressure gauge to be tested, a pressurizing mechanism, a standard piston pressure gauge, and a pressure transmission medium oil cup;

[0016] There are 2 to 4 laser position sensors, which are evenly distributed below the piston pressure gauge to be tested and the standard piston pressure gauge; the laser position sensors can feedback the equilibrium position;

[0017] A kilogram weight is placed above the piston pressure gauge being tested, and a neodymium iron boron magnet is placed above the kilogram weight;

[0018] The configuration weight block is located on the electronic balance, and a magnet fixing device is fixedly connected to the configuration weight block. The magnet fixing device is ring-shaped around the electronic balance, and a neodymium iron boron magnet is connected below the electronic balance of the magnet fixing device;

[0019] There are two NdFeB magnets, one is located above the kilogram weight, and the other is located on the magnet fixing device extending from the configuration weight block; the two NdFeB magnets are opposite to each other and repel each other;

[0020] The pressure transmission medium oil cup is located between the piston pressure gauge to be tested and the standard piston pressure gauge;

[0021] The pressurizing mechanism can load pressure into the piston pressure gauge calibration system;

[0022] Furthermore, the electronic balance can measure the magnitude of the mutual repulsion between the two NdFeB magnets by configuring a weight block to be fixedly connected with a magnet fixing device;

[0023] Step 2, pressurizing the standard piston and the piston to be calibrated to lift up, and recording the value after the initial equilibrium state. The value after the equilibrium state recorded in step 2 is the pressure value of the piston;

[0024] Step 2 is performed in the piston pressure gauge calibration system built in step 1. When step 2 is performed, the pistons on both sides are pressed up and reach the initial balance. According to Pascal's theorem, it can be obtained that:

[0025] In the formula (1), S 8 is the area of ​​the standard piston pressure gauge, m 8 is the pressure of the standard piston pressure gauge; S 6 is the area of ​​the piston pressure gauge to be calibrated, m 6 is the pressure of the piston pressure gauge to be calibrated;

[0026] Step 3: Add a certain amount of weight to the standard piston and the piston to be calibrated, and record the value after the second balance;

[0027] In step 3, after a certain amount of weight is added to the standard piston and the piston to be calibrated, a second balance is achieved. According to Pascal's theorem, it can be obtained that:

[0028] In the formula (2), ; and Δm 6 The amount of weight added to the piston pressure gauge to be calibrated; Δm 8 The amount of weight added to a standard piston pressure gauge;

[0029] In the process of step 3, the weight of the added weight is not an integer value, but is composed of kilogram weights and gram group (milligram group) weights;

[0030] In the secondary balancing process of step 3, all the weights of the gram group (milligram group) in the process of adding weights can be placed on the piston pressure gauge to be tested;

[0031] In the secondary balance of step 3, two mutually repelling NdFeB magnets are used to replace the gravitational effect of the gram group (milligram group) weights with magnetic field repulsion;

[0032] Step 4: Perform relevant calculations based on the data measured in steps 2 and 3 to calibrate the piston to be calibrated.

[0033] In step 4, the data obtained in steps 2 and 3, that is, equation (1) and equation (2) are subtracted to obtain:

[0034]

[0035] In the formula (3), since S 8 is a standard piston pressure gauge, the standard value is known; and Δm 6 and Δm 8 , are all known, so in formula (3), the three values ​​are known, and the unknown quantity S can be obtained from the proportional relationship 6 Calibration value of

[0036] The calculation related to step 4 is that after the standard piston and the piston to be calibrated are pressed and lifted for the first time in step 2, the magnetic field does not work; at this time, a weight block is configured on the electronic balance and its mass is set to m 1 ;

[0037] The calculation of step 4 is as follows: after step 3 and the second balance, the magnetic field exerts a repulsive force, and the downward force assists the piston pressure gauge calibration system to balance, while the upward reaction force makes the balance weighing m 1 becomes m 2 , the difference between the two is m 1 -m 2 The theoretical amount of weight added is the gram group or milligram group;

[0038] Assuming the amount of kilogram weight added is ΔM, equation (3) can be transformed into:

[0039]

[0040] Therefore, the measured piston area can be calculated as:

[0041]

[0042] By adopting the above scheme, the piston pressure gauge calibration method based on the magnetic balance principle disclosed in the present invention has the following advantages:

[0043] (1) The piston pressure gauge calibration method based on the magnetic balance principle of the present invention is based on the electromagnetic force balance principle. By taking advantage of the characteristics of equal and opposite repulsive forces of the magnetic field, the gravity of the weights originally used for balancing is replaced by a balance standard, without the need for manual addition and subtraction of weights. The balancing force is directly measured by the balance. By comprehensively adopting the feedback signal of the laser position sensor, an automatic calibration auxiliary balancing device is designed, and the process of manually adjusting the balance of the calibration system in the traditional method is abandoned. The possibility of gross errors and random errors caused by human factors in the calibration process is reduced, and the accuracy of calibration is greatly increased.

[0044] (2) The piston pressure gauge calibration method based on the magnetic balance principle of the present invention transforms the process of manually placing weights to achieve balance into a process of real-time continuous reading of force values ​​by a balance to finally achieve balance through the electromagnetic balance principle, thereby automatically acquiring key parameter balance quality data, and finally realizing the automation of the piston pressure gauge calibration process, improving the degree of automation of the calibration method, and making the method of the present invention more in line with the new version of the verification regulations, thereby achieving higher quality piston pressure gauge calibration.

[0045] In summary, the piston pressure gauge calibration method based on the magnetic balance principle disclosed in the present invention reduces the possibility of gross errors and random errors caused by human factors during the calibration process, greatly increases the accuracy of calibration; improves the degree of automation of the calibration method, and makes the method of the present invention more in line with the new version of the verification regulations, thereby achieving higher quality piston pressure gauge calibration.

[0046] The concept, specific technical scheme and technical effects of the present invention will be further described below in conjunction with specific implementation methods to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a flow chart of a piston pressure gauge calibration method based on the magnetic balance principle of the present invention;

[0048] Figure 2 It is a structural schematic diagram of a piston pressure gauge calibration system in a piston pressure gauge calibration method based on the magnetic balance principle of the present invention;

[0049] In the figure, 1. Laser position sensor; 2. Configuration weight; 3. Electronic balance; 4. NdFeB magnet; 5. Kilogram weight; 6. Tested piston pressure gauge; 7. Pressurizing mechanism; 8. Standard piston pressure gauge; 9. Pressure transmission medium oil cup. DETAILED DESCRIPTION

[0050] The following introduces several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, which are exemplary descriptions, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0051] Embodiment 1: A piston pressure gauge calibration method based on the magnetic balance principle is used to calibrate a piston pressure gauge;

[0052] The piston pressure gauge to be calibrated in Example 1 is (1-60) MPa. The area of ​​the standard piston pressure gauge used in Example 1 is 0.098112 cm 2 ; Figure 1 It is a schematic diagram of the process of the present invention. This embodiment 1 is also as follows Figure 1 The flowchart shown is executed;

[0053] First, step 1 is performed to build a piston pressure gauge calibration system; Figure 2 is a schematic diagram of a piston pressure gauge calibration system constructed in Example 1;

[0054] The piston pressure gauge calibration system constructed in step 1 includes a laser position sensor 1, a configuration weight 2, an electronic balance 3, a neodymium iron boron magnet 4, a kilogram weight 5, a piston pressure gauge to be tested 6, a pressurizing mechanism 7, a standard piston pressure gauge 8, and a pressure transmission medium oil cup 9;

[0055] In specific implementation, there are two laser position sensors 1 in this embodiment 1, one is below the piston pressure gauge 6 to be tested, and the other is below the standard piston pressure gauge 8; the laser position sensor 1 can feedback the equilibrium position;

[0056] Above the piston pressure gauge 6 to be tested is a kilogram weight 5, and above the kilogram weight 5 is a neodymium iron boron magnet 4;

[0057] The configuration weight block 2 is located on the electronic balance 3, and a magnet fixing device is fixedly connected to the configuration weight block 2. The magnet fixing device is ring-shaped around the electronic balance 3, and a neodymium iron boron magnet 4 is connected below the electronic balance 3 of the magnet fixing device;

[0058] There are two NdFeB magnets 4, one is located above the kilogram weight 5, and the other is located on the magnet fixing device extending from the configuration weight 2; the two NdFeB magnets 4 are opposite to each other and repel each other;

[0059] The pressure transmission medium oil cup 9 is located between the piston pressure gauge 6 to be tested and the standard piston pressure gauge 8;

[0060] The pressurizing mechanism 7 can load pressure into the piston pressure gauge calibration system;

[0061] The electronic balance 3 can measure the magnitude of the mutual repulsion between the two NdFeB magnets 4 by configuring a magnet fixing device fixedly connected to the weight block 2;

[0062] After completing the construction of the piston pressure gauge calibration system, you can start step 2, pressurize the standard piston and the piston to be calibrated, and record the value after the initial equilibrium state;

[0063] The value after the equilibrium state recorded in step 2 is the pressure value of the piston;

[0064] Step 2 is performed in the piston pressure gauge calibration system built in step 1. When step 2 is performed, the pistons on both sides are pressed up and reach the initial balance. According to Pascal's theorem, it can be obtained that:

[0065] In the formula (1), S 8 is the area of ​​the standard piston pressure gauge, m 8 is the pressure of the standard piston pressure gauge; S 6 is the area of ​​the piston pressure gauge to be calibrated, m 6 is the pressure of the piston pressure gauge to be calibrated;

[0066] In this embodiment 1, when it is implemented, S 8 =0.098112cm 2 ;

[0067] After step 2 is completed, step 3 can be started, adding a certain amount of weight to the standard piston and the piston to be calibrated, and recording the value after the second balance;

[0068] In step 3, after a certain amount of weight is added to the standard piston and the piston to be calibrated, a second balance is achieved. According to Pascal's theorem, it can be obtained that:

[0069] In the formula (2), ; and Δm 6 The amount of weight added to the piston pressure gauge to be calibrated; Δm 8 The amount of weight added to a standard piston pressure gauge;

[0070] In the process of step 3, the weight of the added weight is not an integer value, but is composed of kilogram weights and gram group (milligram group) weights;

[0071] In the secondary balancing process of step 3, all the weights of the gram group (milligram group) in the process of adding weights can be placed on the piston pressure gauge to be tested;

[0072] In the secondary balance of step 3, two mutually repelling NdFeB magnets are used to replace the gravitational effect of the gram group (milligram group) weights with magnetic field repulsion;

[0073] Finally, step 4 is performed to perform relevant calculations based on the data measured in steps 2 and 3 to calibrate the piston to be calibrated;

[0074] In step 4, the data obtained in steps 2 and 3, that is, equation (1) and equation (2) are subtracted to obtain:

[0075]

[0076] In the formula (3), since S 8 is a standard piston pressure gauge, the standard value is known; and Δm 6 and Δm 8 , are all known, so in formula (3), the three values ​​are known, and the unknown quantity S can be obtained from the proportional relationship 6 Calibration value; the calculation of step 4, in step 2, the first time the standard piston and the piston to be calibrated are pressed up, the magnetic field does not work; at this time, the electronic balance is equipped with a weight and its mass is m 1 ;

[0077] The calculation of step 4 is as follows: after step 3 and the second balance, the magnetic field exerts a repulsive force, and the downward force assists the piston pressure gauge calibration system to balance, while the upward reaction force makes the balance weighing m 1 becomes m 2 , the difference between the two is m 1 -m 2 The theoretical amount of weights added for the gram group and milligram group; the whole process is completed automatically, and the proper mass of the weights for the gram group (milligram group) can be automatically obtained;

[0078] Assuming the amount of kilogram weight added is ΔM, equation (3) can be transformed into:

[0079]

[0080] Therefore, the measured piston area can be calculated as:

[0081]

[0082] In specific implementation, after the calibration system is set up in step 1, this embodiment 1 performs steps 2, 3, and 4 a total of 10 times; the specific calibration data results are shown in Table 1 below;

[0083] Table 1 Piston press calibration data

[0084]

[0085]

[0086] From the piston press calibration data in Table 1 above, after calculating the arithmetic average of 10 test data, we can get S 6 =0.050045cm 2 ;

[0087] The experimental standard deviation S A' =0.0000003cm 2 , δ A' = ±3S A' = ±0.000001cm 2 , that is, the calibration requirements are met. Through the calibration method of this embodiment 1, the calibration of this (1-60) MPa piston pressure gauge is completed accurately and efficiently.

[0088] Comparative Example 1: A piston pressure gauge calibration method using a digital pressure gauge as a standard in the prior art is used to calibrate a (1-60) MPa piston pressure gauge.

[0089] The piston pressure gauge calibrated in this comparative example 1 is the same as that in Example 1, and the area of ​​the standard piston pressure gauge used is also 0.098112 cm 2 ; When the calibration method of the prior art is used, after avoiding careless errors and random errors in human factors as much as possible, after obtaining the calibration data of 10 piston presses, the calibration results obtained cannot meet the calibration of this (1-60) MPa piston pressure gauge;

[0090] A comprehensive analysis shows that the calibration method using the existing technology does not meet the relevant calibration requirements in the latest national regulations of JJG 59-2022, and the calibration method of this embodiment 1 is limited to low-grade pistons below grade 0.05, and the application level is low. It is impossible to accurately calibrate the same (1-60) MPa piston pressure gauge calibrated in Example 1 of the present invention.

[0091] In summary, the technical solution of this patent is based on the principle of electromagnetic force balance. Through the characteristics of equal and opposite repulsive forces of the magnetic field, the gravity of the weights originally used for balance is replaced by a balance standard. There is no need to manually add or subtract weights, and the balance force is directly weighed by the balance. By comprehensively adopting the feedback signal of the laser position sensor, an automatic calibration auxiliary balance device is designed, and the process of manually adjusting the balance of the calibration system in the traditional method is abandoned. The possibility of gross errors and random errors caused by human factors during the calibration process is reduced, and the accuracy of calibration is greatly increased. Through the principle of electromagnetic balance, the process of manually placing weights to achieve balance is transformed into a process in which the balance continuously reads the force value in real time to finally achieve balance, so that the key parameter balance quality data is automatically acquired, and finally the automation of the piston pressure gauge calibration process is realized, the degree of automation of the calibration method is improved, and the method of the present invention is made more in line with the new version of the verification regulations, and a higher quality piston pressure gauge calibration is achieved.

[0092] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A piston pressure gauge calibration method based on the magnetic balance principle, characterized in that: The steps include: Step 1: Build a piston pressure gauge calibration system; The piston pressure gauge calibration system constructed in step 1 comprises a laser position sensor (1), a configuration weight (2), an electronic balance (3), a neodymium iron boron magnet (4), a kilogram weight (5), a piston pressure gauge to be tested (6), a pressurizing mechanism (7), a standard piston pressure gauge (8), and a pressure transmission medium oil cup (9); There are 2 to 4 laser position sensors (1) in total, which are evenly distributed below the piston pressure gauge (6) to be tested and the standard piston pressure gauge (8); the laser position sensors (1) are used to feedback the equilibrium position; A kilogram weight (5) is disposed above the piston pressure gauge (6) to be tested, and a neodymium iron boron magnet (4) is disposed above the kilogram weight (5); The configuration weight block (2) is located on the electronic balance (3), a magnet fixing device is fixedly connected to the configuration weight block (2), the magnet fixing device is ring-shaped around the electronic balance (3), and a neodymium iron boron magnet (4) is connected below the electronic balance (3) of the magnet fixing device; There are two NdFeB magnets (4), one of which is located above the kilogram weight (5) and the other is located on a magnet fixing device extending from the configuration weight block (2); the two NdFeB magnets (4) are opposite to each other and repel each other; The pressure transmission medium oil cup (9) is located between the piston pressure gauge (6) to be tested and the standard piston pressure gauge (8); The pressurizing mechanism (7) is used to load pressure into the piston pressure gauge calibration system; The electronic balance (3) is configured with a weight block (2) on which a magnet fixing device is fixedly connected to measure the magnitude of the mutual repulsion between the two NdFeB magnets (4); Step 2: Press the standard piston and the piston to be calibrated up, and record the values ​​after they reach the initial equilibrium state; Step 3: Add a certain amount of weight to the standard piston and the piston to be calibrated, and record the value after the second balance; Step 4: perform relevant calculations based on the data measured in steps 2 and 3 to calibrate the piston to be calibrated.

2. The piston pressure gauge calibration method according to claim 1, characterized in that: The value after the equilibrium state recorded in step 2 is the pressure value of the piston; Step 2 is performed in the piston pressure gauge calibration system built in step 1. When step 2 is performed, the pistons on both sides are pressed up and reach the initial balance. According to Pascal's theorem, it is obtained that: (1); In the formula (1), S8 is the area of ​​the standard piston pressure gauge, m8 is the pressure of the standard piston pressure gauge; S6 is the area of ​​the piston pressure gauge to be calibrated, and m6 is the pressure of the piston pressure gauge to be calibrated.

3. The piston pressure gauge calibration method according to claim 1, characterized in that: In step 3, after a certain amount of weight is added to the standard piston and the piston to be calibrated, a second balance is achieved, and Pascal's theorem shows: (2); In the formula (2), The amount of weight to add to the piston gauge to be calibrated; The amount of weight added to a standard piston pressure gauge; In the process of step 3, the added weights are composed of kilogram weights, gram weights, and milligram weights; During the secondary balancing process of step 3, all the weights of the gram group and milligram group in the process of adding weights are placed on the piston pressure gauge to be tested; In the secondary balance of step 3, two NdFeB magnets that repel each other are used, and the magnetic field repulsion is used to replace the gravitational effect of the gram group and milligram group weights.

4. The piston pressure gauge calibration method according to claim 1, characterized in that: In step 4, the data obtained in steps 2 and 3, that is, formula (1) and formula (2) are subtracted to obtain: （3）； In the formula (3), since S8 is a standard piston pressure gauge, the standard value is known; and and , are all known, so in formula (3), the three values ​​are known, and the calibration value of the unknown quantity S6 is obtained by the proportional relationship; The calculation related to step 4 is that after the standard piston and the piston to be calibrated are initially pressed and lifted up for the first time in step 2, the magnetic field does not act; at this time, a weight block is configured on the electronic balance and its mass is set to m1; The relevant calculation of step 4 is that after step 3 and the second balance, the magnetic field plays a role in generating repulsive force, and the downward force assists the piston pressure gauge calibration system to balance. At the same time, the upward reaction force makes the m1 weighed by the balance become m2. The difference between the two, m1-m2, is the theoretical addition amount of the gram group and milligram group weights.

5. The piston pressure gauge calibration method according to claim 1, characterized in that: In step 4, the amount of kilograms of weight added is , then (3) is transformed into: （4）； Therefore, the measured piston area is calculated as: （5）。

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