Automatic inspection equipment for safety valves

Abstract

To provide a device and a method for automatically examining a safety valve which can accurately measure the pressure of each action of a safety valve such as starting of blowing, blowing-out, and stopping of blowing, and for rapidly examining the pressure of the safety valve by shortening time to reach the blowing start pressure.SOLUTION: An automatic examination device is for measuring the operational pressure of a safety valve by flowing an inspection fluid into an examination flow passage to which a workpiece of a safety valve is connected. An examination flow passage 2 has a primary side flow passage 11 for supplying an examination fluid and a secondary side flow passage 12 for measuring an operational pressure of the workpiece 3, the primary side flow passage and the secondary side flow passage being provided across a workpiece 3. The primary side flow passage 11 is provided with pressure adjusting means 21 for adjusting the supply pressure of an examination fluid and pressure measuring means 22 for measuring a pressure, the means 21 and 22 being connected to a control unit 32 for control. The control unit 32 sets the pressure rising speed immediately before the examination fluid reaches the blowing start pressure to be higher than the pressure rising rate from immediately before the examination fluid reaches the blowing start pressure to when the examination fluid reaches the blowing start pressure.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an automatic inspection device for a safety valve for inspecting the operating pressure and valve seat leakage of the safety valve. [Background technology]

[0002] Conventionally, safety valves have been subject to standards for operating pressures such as start of blowing, blowing out, and blowing out, as well as valve seat leakage amounts, which are determined according to the size, location of use, etc., and are inspected before being supplied to the market to ensure that these standards are met. Devices for inspecting safety valves include audible confirmation of the sound of test gas leaking from the safety valve, and visual confirmation of the swelling state of soapy water placed on the outlet side of the safety valve, but both of these not only complicate the entire device and the inspection procedures, but also make it difficult to determine whether the safety valve is operating properly in a single inspection, depending on the level of skill of the worker, as these are inspections that require auditory and visual confirmation.

[0003] In response to this, an automatic safety valve inspection device is known that uses a sensor to measure the pressure of the test fluid supplied to the safety valve under automatic control and determines the test results from the measured value, thereby improving the accuracy of the inspection. One such inspection device is one in which a primary flow path and a secondary flow path are each provided with a single pipe line sandwiching the safety valve for inspection, and the test fluid is passed through the primary flow path and the pressure is measured by a pressure sensor provided on the secondary flow path side.

[0004] On the other hand, in the safety valve operation test device disclosed in Patent Document 1, a test flow path is provided in a closed loop from a gas cylinder for supplying pressure through a header, and multiple solenoid valves are connected to this flow path. In this safety valve test device, the safety valve is tested while switching between the inlet and outlet flow paths to the safety valve by controlling the opening and closing of the solenoid valves.

[0005] When inspecting the operating pressure of a safety valve using these inspection devices, the main inspection items are the onset pressure, blow-out pressure, and receding pressure, and it is necessary to measure each of these pressures accurately and quickly using the inspection device, along with the valve seat leakage amount, etc. The onset pressure is the inlet pressure when the pressure on the inlet side increases and a small amount of fluid is detected leaking out from the outlet side, the receding pressure is also called the popping pressure and is the inlet pressure when the safety valve rapidly opens (pops), and the receding pressure is also called the reseat pressure and is the static inlet pressure when the valve disc re-contacts the valve seat or the lift becomes zero. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 6-137988 Summary of the Invention [Problem to be solved by the invention]

[0007] In the case of the former testing device in which the primary flow path and the secondary flow path are each composed of a single pipe, the onset pressure, outlet pressure, and retract pressure are measured within this single pipe, and the initial onset pressure is measured by detecting the minute flow rate when the test fluid starts to leak from a state in which there is no outlet (outflow) of the test fluid, and the pressure from outlet to retract is measured by detecting the outflowing pressure value. In this case, if a pressure sensor designed to measure minute flow rates is used, it becomes difficult to measure the pressure of large flow rates, and if a pressure sensor designed to measure large flow rates is used, it becomes difficult to measure minute flow rates. Therefore, if one pressure sensor is used in common, it is difficult to accurately measure and judge everything from the onset pressure to the outlet and retract pressures (from minute flow rates to large flow rates). On the other hand, in the latter case of Patent Document 1, the test flow path is a single closed-loop flow path, so as with the above-mentioned test device, when a single pressure measurement sensor is used in common, it becomes difficult to accurately measure the blow-out pressure, blow-out pressure, and retraction pressure.

[0008] When pressure testing a safety valve with any of these pressure testing devices, manual pressure increase up to the blow-off pressure at the start of testing requires skill, and even an experienced person has difficulty quickly increasing the pressure to the blow-off pressure and accurately measuring the blow-off pressure. On the other hand, even when the pressure increase up to the blow-off pressure is automated, in order to accurately measure the blow-off boundary pressure, the measurement must be performed while gradually increasing the pressure, and since it takes time to reach the blow-off pressure, it takes a long time to test one safety valve.

[0009] The present invention was developed to solve the problems of the prior art, and its purpose is to provide an automatic inspection device for safety valves that can accurately measure the operating pressures of a safety valve at the start of blowing, the discharge of blowing, and the end of blowing, and that can quickly inspect the pressure of a safety valve by shortening the time it takes to reach the start of blowing pressure. [Means for solving the problem]

[0010] In order to achieve the above object, the invention according to claim 1 is an automatic testing device that measures the operating pressure of a safety valve by flowing a test fluid into a test flow path connected to a workpiece consisting of a safety valve, the test flow path having a primary side flow path for supplying the test fluid and a secondary side flow path for measuring the operating pressure of the workpiece, with the workpiece sandwiched between them, and the primary side flow path is provided with a pressure adjustment means for adjusting the supply pressure of the test fluid and a pressure measurement means for measuring the pressure, both of which are connected to a control unit for control; The secondary flow path is provided so that the required blowing start pressure for the workpiece can be measured when the test fluid pressurized to an appropriate pressure is supplied to the workpiece, The control unit sets the pressure increase rate until just before the test fluid reaches the blow start pressure to be faster than the pressure increase rate from just before the test fluid reaches the blow start pressure to the blow start pressure. When measuring the initial pressure, the pressure of the test fluid is controlled to increase gradually. This is an automatic inspection device for safety valves.

[0011] The invention according to claim 2 is an automatic inspection device for a safety valve in which the pressure of the test fluid just before it reaches the blowing start pressure is set to approximately 90% of the blowing start pressure required for the workpiece.

[0012] The invention of claim 3 is an automatic inspection device for a safety valve in which the pressure adjustment means is provided with a regulator whose opening is controlled by a stepping motor, and the inspection fluid whose flow rate is adjusted by this regulator can be supplied to the workpiece from the primary side flow path at a desired pressure. [Effects of the Invention]

[0013] According to the invention of claim 1, in the inspection flow path, a pressure adjusting means and a pressure measuring means are provided in a state connected to a control unit in the primary side flow path for supplying the inspection fluid to the work, and this control unit sets the pressure increase rate until just before the inspection fluid reaches the blow start pressure to be faster than the pressure increase rate from just before reaching this blow start pressure to the blow start pressure, thereby shortening the time until the blow start pressure is reached and quickly carrying out pressure inspection of the work, and also making it possible to find works that do not meet the design value of the blow start pressure at an early stage. The secondary flow path is provided so that the required blowing pressure for the work can be measured when the test fluid pressurized to an appropriate pressure is supplied to the work, and when measuring the blowing pressure, the pressure of the test fluid is controlled so that it increases gradually and continuously, thereby enabling the blowing pressure to be measured quickly and accurately. High-precision measurements become possible.

[0014] According to the invention of claim 2, by setting the pressure of the test fluid just before the start of blowing pressure to a pressure that is approximately 90% of the start of blowing pressure required for the work, the pressure rise rate can be increased without exceeding the start of blowing pressure, thereby shortening the time required for testing and making it possible to measure the start of blowing pressure while preventing damage or failure of the micro-leak sensor used to measure the minute flow rate in the secondary flow path.

[0015] According to the invention of claim 3, the flow rate of the test fluid can be adjusted with high precision by the regulator using a stepping motor, and thus pressure adjustments can be made precisely by automatic control when the start pressure, end pressure, and stop pressure cross thresholds during measurement, making it possible to accurately measure these pressures. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing an example of an automatic inspection device for a safety valve according to the present invention. FIG. [Figure 2] 2 is a schematic diagram showing a state in which a large leakage flow path of the inspection flow path in FIG. 1 is opened. FIG. [Figure 3] 3 is a schematic diagram showing a state in which a slight leakage flow path of the inspection flow path in FIG. 2 is opened. FIG. [Figure 4] 4 is a schematic diagram showing a state in which the large leakage flow path of the inspection flow path in FIG. 3 is opened. FIG. [Figure 5] FIG. 2 is a schematic diagram showing an exhaust state inside the workpiece. [Figure 6] FIG. 10 is a schematic diagram showing the state of a flow path during a valve seat leakage test. [Figure 7] FIG. 10 is a schematic diagram showing the state of the flow path when the workpiece is unclamped. [Figure 8] FIG. 1 is a central vertical cross-sectional view showing an example of a safety valve (work). [Figure 9] 1 is a flowchart illustrating an example of an automatic inspection method for a safety valve. [Figure 10] 10 is a flowchart of the automatic inspection method for a safety valve, continuing from FIG. 9. [Figure 11] 4 is a graph showing a pressure increase process of a safety valve. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, the automatic inspection device for safety valves according to the present invention will be described in detail based on an embodiment. Figures 1 to 7 show schematic diagrams of an example of an automatic inspection device for safety valves of the present invention (hereinafter referred to as the device main body 1), in which an inspection flow path 2 is provided and a safety valve (work) 3 to be inspected is connected to the inspection flow path 2.

[0018] The device main body 1 is capable of measuring the operating pressures of the safety valve 3, namely, the start pressure, the outlet pressure, and the shutoff pressure, by flowing the test fluid from the test flow path 2 into the safety valve 3 shown in Fig. 8, and is configured to be able to determine the test results by comparing these pressures with comparative design values ​​preset according to the safety valve 3 being tested, i.e., the design value of the operating pressure required for that safety valve 3. Furthermore, the device main body 1 is also configured to perform a valve seat leakage test after testing the operating pressure. The test fluid used for the test is, for example, air or nitrogen gas.

[0019] In this embodiment, the above-mentioned "start pressure", "blowout pressure", and "restart pressure" are defined as specified in JIS_B8210 "Safety valve", that is, "start pressure: the pressure on the inlet side when the pressure on the inlet side increases and a slight outflow of fluid is detected on the outlet side", "blowout pressure: the pressure on the inlet side when the safety valve performs a rapid opening operation (popping). Also called popping pressure", and "restart pressure: the static pressure on the inlet side when the valve disc comes into contact with the valve seat again or the lift becomes zero. Also called re-seating pressure".

[0020] In the figure, the test flow path 2 has a primary side flow path 11 for supplying the test fluid, a secondary side flow path 12 for measuring the operating pressure of the workpiece 3, and an exhaust flow path 13 for exhausting the test fluid, with the primary side flow path 11 and the secondary side flow path 12 being arranged on one side and the secondary side respectively, sandwiching the workpiece 3, and the exhaust flow path 13 being connected to the primary side flow path 11 so as to be able to open and close freely to switch the flow path.

[0021] The primary flow path 11 is provided with a fluid supply source 20 for supplying a test fluid (air or nitrogen gas), a pressure adjusting means 21, a pressure measuring means 22, and an NC (normally closed) pressurizing electromagnetic valve 23 for opening and closing the flow path. Of these, the fluid supply source 20 is made up of an air pump, and is capable of supplying air, which is the test fluid, to the test flow path 2 (primary flow path 1) with a source pressure (supply pressure) of, for example, 3.5 MPa or more.

[0022] The pressure adjusting means 21 is provided to adjust the supply pressure of the test fluid, and includes a stepping motor 30 and a regulator 31 whose opening can be controlled by the stepping motor 30. A control unit 32 provided for control is provided to adjust the opening of the regulator 31 by controlling the rotation amount of the stepping motor 30, and the pressure of the test fluid is adjusted through the regulator 31. The pressure-adjusted test fluid can be supplied from the primary flow path 11 to the workpiece 3 at a desired pressure. The pressure measuring means 22 is made up of a commonly used pressure sensor, and the pressure in the primary flow path 11 measured by this pressure sensor 22 is detected by the control unit 32 .

[0023] The pressure adjusting means 21 and the pressure measuring means 22 are electrically connected to the control unit 32. In the drawing, the dashed dotted line indicates the state in which the pressure adjusting means 21 and the pressure measuring means 22 are electrically connected.

[0024] The control unit 32 is electrically connected to the pressure adjustment means 21, the pressure measurement means 22, and the pressurizing solenoid valve 23, as well as to components such as solenoid valves and sensors provided in the exhaust flow path 13 and secondary side flow path 12 described below, thereby making it possible to control the operation of solenoid valves and the like other than those in the primary side flow path 11 of the inspection flow path 2, and to detect measurement values ​​using sensors.

[0025] The control unit may also have a function to record pressure measurement values, store set values ​​for operating pressure based on the start pressure, end pressure, and blow-off pressure set for each work 3, and set values ​​such as pressure for valve seat leakage testing for comparison purposes, and determine various test results by comparing these set values ​​with the measurement values.

[0026] 11, the control unit 32 controls the operation of the pressure adjusting means 21 so that the rate of pressure increase from the start of the test until just before the test fluid reaches the blow-start pressure (section A) is faster than the rate of pressure increase from just before the test fluid reaches the blow-start pressure to the blow-start pressure (section B). Input devices such as a monitor and keyboard (not shown) may also be connected to the control unit 32 to check the test results and input settings.

[0027] The pressurizing electromagnetic valve 23 is connected to the secondary side of the pressure adjusting means 21 and the pressure measuring means 22 for pressurizing the fluid, and is provided so as to be able to open and close the primary side flow path 11 under the control of the control unit 32 .

[0028] A pressure sensor 35 and an NO (normally open) solenoid valve 37 for exhaust are provided in the exhaust flow path 13. The pressure sensor 35 and the solenoid valve 37 for exhaust are controlled by the control unit 32, and the test fluid can be discharged from the exhaust flow path 13 by opening and closing the solenoid valve 37 for exhaust while the pressure sensor 35 measures the pressure inside the flow path.

[0029] The secondary flow path 12 is a flow path for measuring the operating pressure of the workpiece, and is branched into a minute leakage flow path 40 for flowing fluid due to a minute leakage from the workpiece 3, and a large leakage flow path 41 for flowing fluid with a larger flow rate compared to the minute leakage, in a state that can be switched by the control unit 32.

[0030] The fine leak flow path 40 is equipped with a fine leak solenoid valve 50 and a fine leak sensor 51 equipped with a scale capable of measuring the minute flow rate due to the start pressure, while the large leak flow path 41 is equipped with a large leak solenoid valve 52 and a large leak sensor 53 capable of measuring the large flow rate due to the blow-off pressure and the stop pressure. Flow sensors are used as the fine leak sensor 51 and the large leak sensor 53, and it is particularly desirable that the fine leak sensor 51 be equipped with a scale capable of precisely measuring pressure in 0.01 mL / min increments. In this embodiment, the fine leak sensor is FSM-HN-005ML-6A-T (manufactured by CKD, scale 0.25 to 5 mL / min), and the large leak sensor is FSM3-L005U1BH1A1N-AH (manufactured by CKD, scale 15 to 500 mL / min). The slight leakage side solenoid valve 50 , slight leakage sensor 51 , large leakage side solenoid valve 52 , and large leakage sensor 53 are each provided so as to be controllable by the control unit 32 .

[0031] Although not shown, an appropriate workpiece mounting jig is provided at a predetermined position between the primary flow path 11 and the secondary flow path 12. This jig has, for example, a structure including a mounting base on the lower side and a clamp plate on the upper side, with the primary flow path 11 connected to the base side and the secondary flow path 12 connected to the clamp plate side, and the workpiece 3 can be sandwiched between the base and the clamp plate and connected in a sealed state to the inspection flow path 2. The jig for mounting the workpiece 3 can also have various structures other than those described above, as long as it can connect the workpiece 3 in a sealed state and measure its operating pressures (at least the start pressure, the end pressure, and the end pressure).

[0032] 8 shows an example of a safety valve (work) 3 for inspection, in which the operating pressure is measured and a valve seat leakage test is performed by the above-mentioned device main body 1. The safety valve 3 is connected to, for example, a container or a pipe, and has the function of preventing the internal pressure of these from rising above a specified pressure, thereby preventing damage to the container or the pipe.

[0033] The safety valve 3 is a so-called spring-type safety valve that operates against the elastic force of a spring, and includes a cylindrical body 70, a cap 71, and a socket 72. The cap 71 and the socket 72 are screwed onto both ends of the body 70, and an inlet-side through-hole 73 and an outlet-side through-hole 74 are formed in the center of the cap 71 and the socket 72 as an inlet-side flow path and an outlet-side flow path, respectively, through which the test fluid passes, and an annular valve seat 75 is formed to protrude from the secondary side (inside the body) of the inlet-side through-hole 73.

[0034] A cylindrical valve element 76 is attached inside the body 70 while being resiliently biased toward the cap 71 by a coil spring 77, and a seat 78 attached to the cap 71 side of the valve element 76 is capable of being seated on a valve seat 75 by the coil spring 77. Notched grooves 79 are provided at multiple locations on the outer periphery of the valve element 76 along the direction of movement of the valve element, and these notched grooves 79 function as flow paths when the valve is open.

[0035] Under normal conditions, the safety valve 3 maintains a closed state by causing the seat 78 of the valve element 76 to seat on the valve seat 75 due to the resilient force of the coil spring 77. On the other hand, when a predetermined fluid pressure is applied from the inlet-side through-hole 73, the valve element 76 moves against the resilient force of the coil spring 77 due to the pressure, opening the valve, and the pressure from the inlet-side through-hole 73 flows out from the outlet-side through-hole 74 through the notched groove 79, allowing the pressure to be released.

[0036] The safety valve in this example has a bore size of, for example, about 10A to 65A, and is of a flange type in which a mounting flange 71a is formed on the cap 71 that is attached to the container or piping, but is not limited to this flange type and may also be of a screw-type mounting structure in which a male thread is provided on the cap. Furthermore, the operating method of the safety valve 3 is not limited to the spring type, but may be a lever type, weight type, spring balance type, or the like. When inspecting safety valves with different mounting structures or operating methods such as these, this can be easily accommodated by appropriately changing the mounting jig of the device body.

[0037] Next, an example of an automatic inspection method for the safety valve 3 using the above-mentioned device main body 1 will be described in detail based on the flowcharts shown in Figures 9 and 10. In the schematic diagrams during inspection in Figures 1 to 7, solid lines indicate a state in which the test fluid can flow through the inspection flow path 2, and dashed lines indicate a state in which the test fluid is not flowing through the inspection flow path 2.

[0038] First, a start button (not shown) provided on the device main body 1 is turned off, and with no test fluid flowing through the test flow path 2 in Figure 1, various input items such as the operating pressures of the start pressure, the discharge pressure, and the stop pressure corresponding to the safety valve (work) 3, the pressure for valve seat leakage test, and the product number and serial number of the safety valve are set (input) from the control unit 32.

[0039] Next, the new work (safety valve) 3 to be inspected is set (placed) on the base of the jig with the cap 71 facing downward with the inlet-side through-hole 73. This places the work 3 in a predetermined position on the jig.

[0040] By turning on the start button, the device main body 1 starts automatic inspection of the safety valve 3, and the subsequent control of each device such as the solenoid valves and sensors is carried out by the control unit 32.

[0041] When the start button is turned on, the clamp plate descends and clamps the workpiece 3 between the clamp plate and the base. This seals the primary flow path 11 and the inlet through-hole 73, and the secondary flow path 12 and the outlet through-hole 74, respectively, and connects the workpiece 3 to a predetermined position in the device body 1 while preventing external leakage.

[0042] In Figure 2, when measurement of the starting pressure begins, the respective solenoid valves are controlled so that the primary side flow path 11 is open, the large leakage flow path 41 is open, the small leakage flow path 40 is closed, and the exhaust flow path 13 is closed, and the flow path of the secondary side flow path 12 is switched to the large leakage flow path 41.

[0043] In this state, the regulator 31 is opened by controlling the rotation of the stepping motor 30, and the pressure of the test fluid supplied from the primary flow path 11 to the work 2 is set to approximately 50% of the initial blowing pressure required for the work 3. The regulator 31 is opened at a high speed so that the pressure rise rate of the test fluid at this time (section C in FIG. 11) is faster than when the test fluid is supplied during the initial blowing pressure measurement described below.

[0044] The regulator 31 is further opened by the stepping motor 30, and the test fluid to the workpiece 3 is adjusted to be pressurized to approximately 90% of the blowing start pressure required for the workpiece 3. The test fluid is pressurized at this time (section D in FIG. 11) at a rate faster than the rate at which the test fluid is pressurized when the blowing start pressure of the workpiece 3 is measured, and is pressurized to approximately 90%, which is the pressure immediately before the test fluid reaches the blowing start pressure.

[0045] In this case, if the large leak sensor 53 detects a leak from the workpiece 3, the workpiece 3 is judged to be defective, the workpiece 3 is unclamped from the jig, and a new workpiece 3 for inspection or one that has been adjusted to match the operating method is then attached to the jig and a pressure test is carried out. If the large leak sensor 53 does not detect a leak, the pressure continues to be increased.

[0046] As described above, the pressure of the test fluid supplied from the primary flow path 11 to the workpiece 3 is first increased to approximately 50% of the required starting pressure for the workpiece 3, and then increased to approximately 90% of this starting pressure. If the pressure were increased too quickly from the start of the test to just before the starting pressure, for example, if the safety valve started to blow immediately after the start of the pressure increase, it would be impossible to determine the test pressure at which the blowing began, and it would be difficult to determine how much to adjust the safety valve operation. On the other hand, if the rate of increase from the start of the test to the starting pressure were too slow, the test time would be extremely long. Therefore, the test fluid is increased in two stages: first, the pressure of the test fluid supplied from the primary flow path 11 to approximately 50% of the required starting pressure for the workpiece 3, and then increased to approximately 90% of this starting pressure. Note that the values ​​of approximately 50% and approximately 90% may be changed as appropriate. Although the test fluid is increased in two stages, the test fluid may also be increased in three or more stages.

[0047] After the pressure just before the test fluid reaches the blow-start pressure, i.e., the pressure measured by the pressure sensor 35 reaches a pressure of approximately 90% of the blow-start pressure required for the workpiece 3, the solenoid valves are controlled so that the large leakage flow path 41 is closed and the small leakage flow path 40 is open, as shown in Fig. 3. As a result, the blow-start pressure is measured with the secondary side flow path 12 switched to the small leakage flow path 40.

[0048] When measuring the blow-start pressure, the opening speed of the regulator 31 is reduced by the stepping motor 30, and from this state, the pressure is increased to about 50% or about 90% of the blow-start pressure at a pressure increase speed of, for example, about 0.002 MPa / sec (see FIG. 11). Section C, Section D), the pressure of the test fluid is controlled to increase very gradually compared to the actual pressure. During this pressure increase, when the amount of leakage of the test fluid detected by the micro leak sensor 51 crosses (exceeds) a predetermined threshold value (for example, 0.3 mL / min.), the pressure measured by the pressure measuring means 22 is determined to be the blow-start pressure, and this measured pressure value is recorded in the control unit 32.

[0049] Next, as shown in Figure 4, each solenoid valve is controlled so that the large leakage flow path 41 is open and the small leakage flow path 40 is closed, and the secondary side flow path 12 is switched to the large leakage flow path 41, and in this state the outlet pressure and receding pressure are measured.

[0050] When measuring the blowing pressure, the pressure rise rate is faster than when measuring the above-mentioned blowing start pressure, so the pressure of the test fluid rises rapidly. When the discharge capacity of the work 3 when the valve is open reaches its limit, further discharge becomes difficult and the pressure value reaches its peak. The pressure measured by the pressure measuring means 22 when this pressure reaches its peak is determined to be the blowing pressure of the work 3, and this measured pressure value is recorded in the control unit 32.

[0051] After measuring the blow-out pressure, the stepping motor 30 is rotated in the reverse direction, which controls the regulator 31 in the direction of gradually throttling, gradually decreasing the pressure of the test fluid. Accordingly, the pressure measured by the pressure measuring means 22 also decreases. When this pressure measurement value becomes almost zero, that pressure is determined to be the receptacle pressure of the workpiece 3, and that value is recorded in the control unit 32.

[0052] After measuring the receding pressure, the primary flow path 11 and the secondary flow path 12 are closed, and the exhaust flow path 13 is opened, as shown in Figure 5. This causes the test fluid in the workpiece 3 and the test flow path 2 to be exhausted from the exhaust flow path 13, resulting in a reduced pressure.

[0053] 6, the minor leakage flow path 40 of the secondary side flow path 12 is controlled to be in an open state, the major leakage flow path 41 is controlled to be in a closed state, the primary side flow path 11 is controlled to be in a closed state, and the exhaust flow path 13 is controlled to be in a closed state. In this state, the regulator 31 is opened, and the pressure inside the primary side flow path 11 is set to a supply pressure suitable for the valve seat leakage test.

[0054] The primary flow path 11 is controlled to an open state, and a predetermined test pressure is applied to the workpiece 3 to perform a valve seat leak test. In this case, it is confirmed that the pressure of the micro leak sensor 51 is equal to or less than a predetermined threshold value (for example, 0.3 mL / min.). If the pressure is equal to or less than this threshold value, the valve seat leak test is judged to have passed, and the judgment result is recorded in the control unit 32.

[0055] Finally, as shown in Figure 7, each solenoid valve is controlled to switch to the exhaust flow path so that the small leakage flow path 40 is closed, the large leakage flow path 41 is closed, the primary side flow path 11 is closed, and the exhaust flow path 13 is open, and the test fluid in the work 3 and the test flow path 2 is exhausted from the exhaust flow path 13. After exhausting, the workpiece 3 is unclamped from the jig, completing the inspection, and another workpiece 3 can be inspected next.

[0056] It should be noted that the above-mentioned automatic inspection device for safety valves is merely an example, and as necessary, it is possible to appropriately change the configuration of the flow path, the specifications and number of sensors and valves connected to the flow path, their attachment positions in the flow path, etc. Also, with regard to the automatic inspection method for safety valves, it is not necessary to stick to the above-mentioned flow, and it is also possible to appropriately change the pressure increase procedure, pressure settings, etc.

[0057] Next, the functions and effects of the above-described embodiment of the automatic operating device and automatic inspection method for a safety valve of the present invention will be described. The main body 1 of the device has a secondary flow path 12 branched into a small leak flow path 40 and a large leak flow path 41. The flow paths to the small leak flow path 40 and the large leak flow path 41 are switchable by the pressurizing solenoid valve 23. Therefore, when measuring the operating pressure of the workpiece 3, the start pressure is measured by the small leak sensor 51 in the small leak flow path 40, and the end pressure and the stop pressure are measured by the large leak sensor 53 in the large leak flow path 41. Therefore, by using a sensor with a fine pressure measurement scale as the small leak sensor 51 and a sensor with a large pressure measurement scale as the large leak sensor 53, the start pressure, the stop pressure, and the pressure during the valve seat leak test can be measured with high accuracy. By comparing the measured values ​​with the design values ​​of the control unit 32, the pass / fail of the workpiece 3 can be easily determined. Furthermore, because there is no risk of excessive pressure being applied to the small leak sensor 51, which is a small flow rate measurement sensor, damage or failure of the small flow rate measurement sensor can be prevented. Moreover, the slight leakage flow path 40 and the large leakage flow path 41 are branch flow paths that are simply branched from the secondary side flow path 12, which prevents the flow paths from becoming complicated.

[0058] Furthermore, in the primary flow path 11, a regulator 31 and a stepping motor 30 are provided as the pressure adjustment means 21, and a pressure sensor is provided as the pressure measurement means 22, and the control unit 32 sets the pressure increase rate up to just before the blow-start pressure is reached to be faster than the pressure increase rate from just before the blow-start pressure is reached to the blow-start pressure, thereby shortening the time it takes to reach the blow-start pressure. By using these regulator 31, stepping motor 30, and pressure sensor 22, pressure adjustment and pressure measurement can be performed quickly and accurately while simplifying the primary flow path 11.

[0059] Furthermore, since the opening of the regulator 31 is controlled by the stepping motor 30, the pressure of the test fluid can be increased at an extremely small pressure increase rate of 0.002 MPa / sec by precise rotation control of the stepping motor 30, and this small pressure increase rate makes it possible to accurately measure the blow-start pressure.

[0060] When measuring the starting pressure, when switching to the large leakage flow path 41, the pressure increase speed is increased to approximately 90% of the starting pressure required for the work 3, so the pressure can be increased quickly without exceeding the starting pressure, and work 3 whose starting pressure deviates significantly from the design value by approximately 10% can be detected early as a defective product without subsequent measurements of the operating pressure (starting pressure, blow-out pressure, and stop pressure) or without performing a valve seat leakage test.

[0061] The above describes in detail the embodiments of the present invention, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention as described in the claims of the present invention. [Explanation of symbols]

[0062] 1. Device body 2 Inspection flow path 3 Work (safety valve) 11 Primary flow path 12 Secondary flow path 13 Exhaust flow path 21 Pressure adjustment means 22 Pressure sensor (pressure measuring means) 30 Stepping motor 31 Regulator 32 Control section 40 Micro-leakage flow path 41 Large leak channel 51 Micro-leak sensor 53 Large leak sensor

Claims

1. 1. An automatic inspection device for measuring the operating pressure of a safety valve by flowing a test fluid into an inspection flow path connected to a workpiece consisting of a safety valve, wherein the inspection flow path is provided with a primary flow path for supplying the test fluid and a secondary flow path for measuring the operating pressure of the workpiece, with the workpiece sandwiched between them, the primary flow path is provided with a pressure adjustment means for adjusting the supply pressure of the test fluid and a pressure measurement means for measuring the pressure, and these means are connected to a control unit for control, the secondary flow path is provided so that the start pressure required for the workpiece can be measured when the test fluid, which has been pressurized to an appropriate pressure, is supplied to the workpiece, and the control unit sets the rate of pressure increase of the test fluid up to just before it reaches the start pressure to be faster than the rate of pressure increase from just before it reaches the start pressure to the start pressure, and the automatic inspection device for safety valves is characterized in that when the start pressure is measured, the pressure of the test fluid is controlled to continue to increase very gradually.

2. 2. An automatic inspection device for a safety valve according to claim 1, wherein the pressure of the test fluid immediately before reaching the blow-start pressure is set to a pressure that is approximately 90% of the blow-start pressure required for the workpiece.

3. 3. The automatic inspection device for safety valves according to claim 1 or 2, wherein the pressure adjusting means includes a regulator whose opening is controlled by a stepping motor, and the inspection fluid whose flow rate is adjusted by this regulator can be supplied to the workpiece from the primary side flow path at a desired pressure.

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