A press-fitting measurement system and measurement method for a safety valve

Abstract

The present invention relates to a press-fitting measurement system and a measurement method for a safety valve. The measurement system includes a press and a press-fitting assembly. The press-fitting assembly includes a housing, a pressure sensor, a pressure rod, and a detection needle. The upper end of the housing is connected to the press, and the lower end is connected to the pressure rod. The pressure sensor is disposed inside the housing and is communicatively connected to the press. The detection needle is disposed inside the pressure rod. The upper end of the detection needle contacts the pressure sensor, and the lower end of the detection needle extends out of the pressure rod. The pressure rod is used for press-fitting the valve seat of the safety valve. A through hole is provided on the valve seat, and a spring is provided below the valve seat. The detection needle passes through the through hole to measure the elastic force of the spring. When the pressure rod presses the valve seat, the pressure sensor real-time detects the elastic force of the spring and feeds back the elastic force value of the spring to the press, thereby controlling the press-in depth of the valve seat, overcoming the problem of poor consistency of the spring elastic coefficient, ensuring that the opening pressure of the safety valve is within the specified range, reducing the scrap rate of the safety valve, and reducing the processing cost.

Description

Technical Field

[0001] The present invention relates to the technical field of valve testing, and particularly relates to a press-fitting measurement system and a measurement method for a safety valve. Background Art

[0002] As the last barrier for overpressure protection in a pressure system, safety valves are widely used in boilers, pressure vessels, and pressure pipelines. A safety valve is usually in a normally closed state and will automatically open when the medium pressure in the equipment or pipeline exceeds the specified value, and relieve pressure to prevent the pressure in the pipeline or equipment from exceeding the specified value. Existing safety valves generally use spring force to achieve valve sealing and reseating. Currently, the valve seat is generally press-fitted to a fixed depth by a press at one time, but the prerequisite for this process method is that the spring constant of the spring is relatively consistent. However, in the actual production process, the spring constant of the spring is poorly consistent. Therefore, the above press-fitting method easily leads to a large dispersion in the opening force of the safety valve, a high rejection rate of the safety valve, and an increase in the manufacturing cost of the safety valve. Summary of the Invention

[0003] The present invention aims at the existing technical problems and provides a press-fitting measurement system and a measurement method for a safety valve.

[0004] The technical solution for the present invention to solve the above technical problems is as follows: A press-fitting measurement system for a safety valve includes a press and a press-fitting assembly. The press-fitting assembly includes a housing, a pressure sensor, a pressure rod, and a detection needle. The upper end of the housing is connected to the press, and the lower end is connected to the pressure rod. The pressure sensor is disposed inside the housing and is communicatively connected to the press. The detection needle is disposed inside the pressure rod. The upper end of the detection needle is in contact with the pressure sensor, and the lower end of the detection needle extends out of the pressure rod. The pressure rod is used to press-fit the valve seat of the safety valve. A through hole is provided on the valve seat, and a spring is provided below the valve seat. The detection needle passes through the through hole to measure the elastic force of the spring.

[0005] The beneficial effects of the present invention are as follows: By installing the detection needle on the pressure rod, the present invention realizes that when the pressure rod presses the valve seat, the pressure sensor can detect the elastic force of the spring in real time through the detection needle and feedback the elastic force value of the spring to the press. The press controls the moving distance of the press-fitting assembly, thereby controlling the press-in depth of the valve seat, overcoming the problem of poor consistency of the spring constant, ensuring that the opening pressure of the safety valve is within the specified range, reducing the rejection rate of the safety valve, and reducing the processing cost.

[0006] Based on the above technical solution, in order to achieve convenient use and equipment stability, the present invention can also make the following improvements to the above technical solution:

[0007] Further, it further includes a T-shaped rod and a sphere. The T-shaped rod is inserted into the spring. A groove is provided at the upper end of the T-shaped rod. The sphere is placed in the groove. The sphere is in contact with the through holes of the detection needle and the valve seat.

[0008] The beneficial effect of adopting the above further technical solution is that by providing the T-shaped rod, it is convenient to compress the spring. The groove structure realizes the positioning effect on the sphere, avoiding the rolling of the sphere. At the same time, the sphere transmits the opening pressure of the safety valve to the spring. When the opening pressure of the safety valve is reached, the oil pressure applies pressure to the sphere, compressing the spring to deform, and the sphere separates from the through hole of the valve seat, and the safety valve opens.

[0009] Further, it further includes a top block. The top block is located between the pressure sensor and the detection needle. An arc-shaped protrusion is provided on the top block. The arc-shaped protrusion is in contact with the detection needle.

[0010] The beneficial effect of adopting the above further technical solution is that it is convenient to transmit the elastic force of the spring to the pressure sensor and reduce the processing difficulty of the detection needle.

[0011] The present invention also discloses a pressing and measuring method for a safety valve, using the above-mentioned pressing and measuring system, including the following steps:

[0012] Step S10: According to the opening pressure value of the safety valve, calculate the target value F of the spring elastic force, and set the target range value F' and the threshold value f, where the threshold value f is less than the target value F;

[0013] Step S20: The press drives the pressing assembly to move downward, the pressing rod presses the valve seat to compress the spring downward, and at the same time the pressure sensor detects the elastic force of the spring in real time through the detection needle;

[0014] Step S30: When the pressure sensor detects that the elastic force of the spring reaches the threshold value f, the pressure sensor transmits a signal to the press, and the press drives the pressing assembly to move upward, and the pressing rod separates from the valve seat;

[0015] Step S40: The press drives the pressing assembly to move downward, so that the detection needle contacts the sphere, the pressure sensor detects the actual elastic force value of the spring and transmits a signal to the press, and the press drives the detection needle to move upward to separate from the sphere;

[0016] Step S50: According to the target value F and the actual elastic force value of the spring, calculate the distance L that the valve seat moves downward;

[0017] Step S60: The press drives the pressing assembly to move downward, the pressing rod presses the valve seat to move downward by a distance L, and then the press drives the pressing assembly to move upward, and the pressing rod separates from the valve seat;

[0018] Step S70: The press drives the press-fitting assembly to move downward, making the detection needle contact the sphere, and detecting the actual elastic force value of the spring at this time;

[0019] Step S80: Determine whether the actual elastic force value of the spring is within the target range value F'. If so, it is determined to be qualified; if not, execute Step S90;

[0020] Step S90: If the actual elastic force value of the spring is less than the target range value F', repeat Step S50 to Step S80;

[0021] If the actual elastic force value of the spring is greater than the target range value F', it is scrapped.

[0022] The beneficial effect of the measurement method of the present invention is that by combining the press-fitting and measurement systems, the elastic force of the spring is measured in real time when the valve seat of the safety valve is press-fitted, so as to control the press-in depth of the valve seat. Different spring coefficients achieve different press-in depths, thus solving the problem of poor consistency of spring elastic coefficients and high scrapping rate of safety valves; by first pressing the valve seat to the threshold f of the spring, it is ensured that the valve seat and the spring have sufficient adjustment margin, avoiding the problem of scrapping of safety valves caused by one-time press-fitting in the prior art; by detecting the actual elastic force value of the spring with a detection needle, it can not only ensure the accuracy of measurement data, but also facilitate the calculation of the actual displacement value of the valve seat, further ensuring that the safety valve opens within the normal range, improving the qualification rate of the safety valve and reducing the manufacturing cost.

[0023] Further, the target value F of the spring elastic force = P * π(r * sin(90° - β / 2))², where P is the opening pressure of the safety valve, Mpa; r is the radius of the sphere, mm; β is the angle between the valve seat and the tangent of the sphere.

[0024] The beneficial effect of adopting the above further technical solution is that the target value of the spring elastic force is calculated through the opening pressure of the safety valve, the radius of the sphere and the angle value between the valve seat and the sphere, which is convenient to calculate and the calculation result is reliable.

[0025] Further, the distance L = (target value F - actual elastic force value of the spring) / K, where K is the elastic coefficient of the spring.

[0026] The beneficial effect of adopting the above further technical solution is that the actual displacement value of the valve seat is calculated according to the actual elastic force value and the elastic coefficient of the spring, so as to ensure that the opening pressure value of the safety valve is within the specified range, improve the qualification rate of the safety valve and reduce the scrapping rate.

[0027] Further, there is at least one Step S61 between Step S60 and Step S70,

[0028] Step S61: Repeat Step S40 to Step S60.

[0029] The beneficial effect of adopting the above further technical solution is that the distance of each downward movement of the control valve seat is avoided from being too large in a single downward movement of the valve seat, so as to prevent the situation that the elastic force value of the spring exceeds the target range requirement and leads to the scrapping of the safety valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the press-fitting measurement system of the present invention;

[0031] Figure 2 is Figure 1 a partial enlarged view at A in

[0032] Figure 3 It is a schematic diagram of the included angle β of the present invention.

[0033] The reference numerals are recorded as follows: 1, housing; 2, pressure sensor; 3, top block; 4, pressure rod; 5, detection needle; 6, safety valve; 7, valve seat; 8, sphere; 9, T-shaped rod; 10, spring; 11, press. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The principles and features of the present invention will be described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0035] As Figures 1 to 3 shown, the present invention discloses a press-fitting measurement system for a safety valve, which includes a press 11 and a press-fitting assembly. The press-fitting assembly includes a housing 1, a pressure sensor 2, a pressure rod 4 and a detection needle 5. The upper end of the housing 1 is connected to the press 11, and the lower end is connected to the pressure rod 4. The pressure sensor 2 is arranged inside the housing 1 and is communicatively connected to the press 11. The detection needle 5 is arranged inside the pressure rod 4. The upper end of the detection needle 5 is in contact with the pressure sensor 2, and the lower end of the detection needle 5 extends out of the pressure rod 4, so that the detection needle 5 can be used to detect the elastic force of the spring 10 alone. The pressure rod 4 is used to press-fit the valve seat 7 of the safety valve 6. A through hole is provided on the valve seat 7, and a spring 10 is arranged below the valve seat 7. The detection needle 5 passes through the through hole to measure the elastic force of the spring 10.

[0036] The press-fitting measurement system for the safety valve further includes a T-shaped rod 9 and a sphere 8. The T-shaped rod 9 is inserted into the spring 10. A groove is provided at the upper end of the T-shaped rod 9, and the sphere 8 is placed in the groove. The sphere 8 is in contact with the detection needle 5 and the through hole of the valve seat 7.

[0037] The press-fitting measurement system for the safety valve further includes a top block 3. The top block 3 is located between the pressure sensor 2 and the detection needle 5. An arc-shaped protrusion is provided on the top block 3, and the arc-shaped protrusion is in contact with the detection needle 5.

[0038] The present invention also discloses a press-fitting measurement method for a safety valve, which uses the press-fitting measurement system as described above and includes the following steps:

[0039] Step S10: According to the opening pressure value of the safety valve 6, calculate the target value F of the spring 10 elastic force, and set the target range value F' and the threshold value f, where the threshold value f is less than the target value F;

[0040] As Figure 3 shown, the target value F of the spring 10 elastic force = P*πx2 = P×π(r×sinα) = P×π×(r×sin(90° - β / 2)), where the meanings of relevant parameters are as follows: P - the opening pressure of the safety valve, Mpa; x - the distance from the tangent point of the valve seat and the sphere to the sphere radius, mm; α - the angle between the tangent point and the sphere radius; r - the sphere radius, mm; β - the angle between the valve seat and the sphere tangent;

[0041] In this embodiment, the sphere 8 radius r is 1 mm, the angle β is 103°, the opening pressure P of the safety valve 6 is 41 Mpa. According to the above formula, the target value F of the spring 10 elastic force is calculated to be 49.9 N, the target range value F' is 48 N - 52 N, and the threshold value f is 45 N;

[0042] Step S20: The press 11 drives the press-fitting component to move downward, the pressure rod 4 presses the valve seat 7 downward to compress the spring 10, and at the same time the pressure sensor 2 detects the elastic force of the spring 10 in real time through the detection needle 5;

[0043] Step S30: When the elastic force of the spring 10 detected by the pressure sensor 2 reaches the threshold value f, the pressure sensor 2 transmits a signal to the press 11, and the press 11 drives the press-fitting component to move upward, and the pressure rod 4 is separated from the valve seat 7;

[0044] Step S40: The press 11 drives the press-fitting component to move downward so that the detection needle 5 contacts the sphere 8, the pressure sensor 2 detects the actual elastic force value of the spring 10 and transmits a signal to the press 11, and the press 11 drives the detection needle 5 to move upward and separate from the sphere 8; among them, the actual elastic force value of the spring 10 is that the detection needle 5 pushes the sphere 8 to squeeze the spring 10. When the elastic force of the spring 10 has a sudden change, the inflection point value of the spring 10 elastic force at this time is the actual elastic force value of the spring 10, that is, the opening value of the spring 10;

[0045] Step S50: According to the target value F and the actual elastic force value of the spring 10, calculate the distance L that the valve seat 7 moves downward. The distance L = (target value F - actual elastic force value of the spring) / K, where the meanings of relevant parameters are as follows: K - the elastic coefficient of the spring;

[0046] Step S60: The press 11 drives the press-fitting assembly to move downward, and the pressing rod 4 presses the valve seat 7 to move downward by a distance L. Then, the press 11 drives the press-fitting assembly to move upward, and the pressing rod 4 is separated from the valve seat 7.

[0047] Step S70: The press 11 drives the press-fitting assembly to move downward so that the detection needle 5 contacts the sphere 8, and the actual elastic force value of the spring 10 is detected at this time.

[0048] Step S80: Determine whether the actual elastic force value of the spring 10 is within the target range value F'. If so, it is determined to be qualified; if not, execute Step S90.

[0049] Step S90: If the actual elastic force value of the spring 10 is less than the target range value F', repeat Steps S50 to S80.

[0050] If the actual elastic force value of the spring 10 is greater than the target range value F', it is scrapped.

[0051] Further, at least one Step S61 is also included between Step S60 and Step S70. Step S61: Repeat Steps S40 to S60.

[0052] In this embodiment, there is one Step S61, that is, the valve seat 7 is press-fitted in place through two press-fittings and detections, taking into account both the qualification rate and the installation efficiency of the safety valve 6. It not only solves the problem of high scrapping rate of the safety valve 6 caused by press-fitting the valve seat 7 to the specified depth at one time, but also avoids increasing the manufacturing cost due to the increase in the press-fitting man-hour of the safety valve 6 caused by multiple press-fittings.

[0053] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A press-fitting measurement method for a safety valve, using a press-fitting measurement system, characterized in that the press-fitting measurement system includes a press (11) and a press-fitting assembly. The press-fitting assembly includes a housing (1), a pressure sensor (2), a pressure rod (4), and a probe (5). The upper end of the housing (1) is connected to the press (11), and the lower end is connected to the pressure rod (4). The pressure sensor (2) is arranged inside the housing (1), and the pressure sensor (2) is communicatively connected to the press (11). The probe (5) is arranged inside the pressure rod (4). The upper end of the probe (5) is in contact with the pressure sensor (2), and the lower end of the probe (5) extends out of the pressure rod (4). The pressure rod (4) is used for press-fitting the valve seat (7) of the safety valve (6). A through hole is provided on the valve seat (7), and a spring (10) is provided below the valve seat (7). The probe (5) passes through the through hole to measure the elastic force of the spring (10). It also includes a T-shaped rod (9) and a sphere (8). The T-shaped rod (9) is inserted into the spring (10). A groove is provided at the upper end of the T-shaped rod (9), and the sphere (8) is placed in the groove. The sphere (8) is in contact with the probe (5) and the through hole of the valve seat (7); The press-fitting measurement method includes the following steps: Step S10: According to the opening pressure value of the safety valve (6), calculate the target value F of the elastic force of the spring (10), and set the target range value F' and the threshold value f, where the threshold value f is less than the target value F; Step S20: The press (11) drives the press-fitting assembly to move downward, and the pressure rod (4) presses the valve seat (7) to compress the spring (10) downward. At the same time, the pressure sensor (2) detects the elastic force of the spring (10) in real time through the probe (5); Step S30: When the pressure sensor (2) detects that the elastic force of the spring (10) reaches the threshold value f, the pressure sensor (2) transmits a signal to the press (11), and the press (11) drives the press-fitting assembly to move upward, and the pressure rod (4) is separated from the valve seat (7); Step S40: The press (11) drives the press-fitting assembly to move downward so that the probe (5) contacts the sphere (8). The pressure sensor (2) detects the actual elastic force value of the spring (10) and transmits a signal to the press (11), and the press (11) drives the probe (5) to move upward and separate from the sphere (8); Step S50: According to the target value F and the actual elastic force value of the spring (10), calculate the distance L that the valve seat (7) moves downward; Step S60: The press (11) drives the press-fitting assembly to move downward, and the pressure rod (4) presses the valve seat (7) to move downward by a distance L, and then the press (11) drives the press-fitting assembly to move upward, and the pressure rod (4) is separated from the valve seat (7); Step S70: The press (11) drives the press-fitting assembly to move downward so that the probe (5) contacts the sphere (8), and detects the actual elastic force value of the spring (10) at this time; Step S80: Judge whether the actual elastic force value of the spring (10) is within the target range value F'. If it is, it is determined to be qualified; if not, execute Step S90; Step S90: If the actual elastic force value of the spring (10) is less than the target range value F', then repeat steps S50 to S80; if the actual elastic force value of the spring (10) is greater than the target range value F', then perform scrap treatment.

2. The press-fitting measurement method according to claim 1, wherein It further includes a top block (3), the top block (3) is located between the pressure sensor (2) and the detection needle (5), an arc-shaped protrusion is provided on the top block (3), and the arc-shaped protrusion is in contact with the detection needle (5).

3. The press-fitting measurement method according to claim 1, characterized in that, The target value F of the elastic force of the spring (10) = P×π×(r×sin(90° - β / 2)), where P is the opening pressure of the safety valve, in Mpa; r is the radius of the sphere (8), in mm; β is the angle between the valve seat and the tangent of the sphere.

4. The press-fitting measurement method according to claim 1, wherein The distance L = (target value F - actual elastic force value of the spring) / K, where K is the elastic coefficient of the spring.

5. The press-fitting measurement method according to claim 1, characterized in that There is at least one step S61 between step S60 and step S70. Step S61: Repeat steps S40 to S60.

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