JP4843111B1 - Maintenance method of automatic open / close valve - Google Patents

Abstract

An automatic on-off valve suitable for accurately grasping the movement of a valve body, constantly grasping a mechanical wear state, and predicting a maintenance time is provided.
An automatic opening / closing valve according to the present invention is connected to a valve body shaft 2 rotatable around an axis, a valve body fixed to the valve body shaft 2, and a valve body shaft 2 via a connecting portion 5. Drive shaft 4 and drive means for rotationally driving the drive shaft 4, and by operating the drive means, the valve body shaft 2 reciprocates between an open position and a closed position, thereby opening and closing the valve body. The automatic open / close valve is configured to automatically operate, and includes detection means 7 for detecting whether the valve body shaft 2 is in the open position or the closed position.
[Selection] Figure 3

Description

The present invention relates to a maintenance management method for an automatic opening / closing valve configured to automatically and repeatedly perform opening / closing operation of a valve body.

  As a method for separating and purifying nitrogen gas, oxygen gas, hydrogen gas, argon gas, etc., a pressure fluctuation adsorption method (PSA method) performed using an adsorption tower filled with an adsorbent is known. In gas separation by the PSA method, an automatic opening / closing valve for switching the gas flow is installed at the entrance / exit of the adsorption tower, and the valve body of each automatic opening / closing valve is changed from the closed state to the open state, or from the open state to the closed state. The PSA operation is performed at intervals of several tens of seconds to several minutes. For this reason, the number of opening and closing operations of the valve body in the automatic opening and closing valve reaches about 200 to 1 million times a year.

  For example, a butterfly valve is used as the automatic opening / closing valve. The butterfly valve includes a valve body shaft rotatable around an axis, a disc-shaped valve body fixed to the valve body shaft, a drive shaft coupled to the valve body shaft via a joint portion, and a drive shaft Driving means for rotationally driving the motor. The drive means is configured such that, for example, an operation of an actuator such as a motor, a hydraulic pressure or a pneumatic cylinder is transmitted as a rotation operation of the drive shaft via a transmission mechanism. A technique related to such an automatic opening / closing valve (butterfly valve) is described in Patent Document 1, for example.

  When the butterfly valve is used as an automatic opening / closing valve for PSA operation, as described above, by opening and closing the valve body at a high frequency over a long period of time, the seal portion in contact with the valve body is worn and the valve body is brought into a closed state. There is a possibility that the airtightness at a certain time is impaired. Further, by repeating the opening and closing operation of the valve body, the connecting portion that connects the valve body shaft and the drive shaft may be worn, and rattling may occur in the connecting portion. If rattling occurs in the connecting part, the valve body shaft cannot take the closed position where the valve body is completely closed even if the drive shaft is driven to rotate properly. It is not possible to take an open position that is in an open state. As a result, during the opening / closing operation of the valve body, the valve body may not be completely closed or may not be fully opened.

  For such inconvenience due to mechanical wear of the automatic opening / closing valve, for example, mechanical wear has occurred by measuring the differential pressure change between the upstream side and the downstream side with the valve body closed. There are cases where measures are taken such as indirectly detecting and performing maintenance such as replacement of parts of the automatic opening / closing valve. However, in response to maintenance by measuring such a pressure change, it is difficult to grasp the mechanical wear state of the automatic open / close valve during operation and to predict the maintenance time of the automatic open / close valve in advance.

Japanese Utility Model Publication 2-541

The present invention, which was conceived under such circumstances, capture the movement of the valve member accurately, in the automatic on-off valve suitable for constantly monitors the mechanical wear condition during operation, its maintenance It has been a challenge to provide a maintenance management method capable of predicting the time in advance.

An automatic open / close valve that is a subject of the present invention includes a valve body shaft that is rotatable about an axis, a valve body that is fixed to the valve body shaft, and a drive shaft that is coupled to the valve body shaft via a coupling portion. Drive means for rotationally driving the drive shaft, and the operation of the drive means causes the valve body shaft to reciprocate between an open position and a closed position, thereby automatically opening and closing the valve body. It is an automatic opening / closing valve configured to be performed, and is characterized by comprising detection means for detecting whether or not the valve body shaft is in the open position or the closed position.

  Preferably, the detection means includes a detection unit fixed to the valve body shaft, and a proximity switch that detects the approach of the detection unit when the valve body shaft is in the open position or the closed position. It is configured.

Maintenance method of an automatic on-off valve which is in the onset Ming Thus provided is for target automatic opening and closing valve of the above configuration, the valve body shaft reciprocates between said open position and said closed position The number of actuations is defined as the number of actuations, and the time until the valve body shaft rotates from the closed position to the open position or from the open position is rotated at each of the actuation times using the detection result of the detection means. Then, the time until the closed position is measured as the operation time, the operation time at the first operation is set as the initial operation time, and the rate of change in which the operation time decreases at a predetermined number of operations with respect to the initial operation time ( It is characterized in that it is determined that the maintenance time is reached when the operating time change rate becomes equal to or less than a predetermined value.

In the method of the present invention, preferably, the operation time change rate when the number of operations is 300,000 is in the range of more than 10% and 60% or less, and the operation is performed every 100,000 operations thereafter. When the time change rate is 10% or less, it is determined that the maintenance time is reached.

In the method of the present invention, preferably, when the operation time becomes equal to or longer than a set time, the valve body shaft is rotated to the closed position to close the valve body.

In the method of the present invention, preferably, the set time is the initial operation time.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

It is the schematic front view which notched and represented a part of automatic on-off valve which the method of this invention makes object . It is the principal part enlarged view which notched and represented a part of FIG. It is principal part sectional drawing in alignment with the III-III line of FIG. It is a graph which shows an example of the relationship between the frequency | count of operation | movement of a valve body shaft, and operation time. It is a graph which shows the other example of the relationship between the frequency | count of operation | movement of a valve body shaft, and operation time.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings.

1 to 3 show an embodiment of an automatic on-off valve targeted by the method of the present invention. As shown in FIG. 1, the automatic opening / closing valve X of the present embodiment includes a valve case 1, a valve body shaft 2, a disc-shaped valve body 3, and a drive shaft 4. It is configured as an eccentric butterfly valve that can be opened and closed.

  The valve body shaft 2 is supported by the valve case 1 so as to be rotatable around a predetermined axis. More specifically, a flange 12 incorporating a seal member 11 is attached to the lower portion of the valve case 1, and the valve body shaft 2 is supported by the flange 12 via a retainer 21 provided at the lower end thereof. . A seal member 13 is provided between the valve case 1 and the upper part of the valve body shaft 2. The seal member 13 is pressed by a flange 14 attached to the upper part of the valve case 1. Even if the valve body shaft 2 rotates, the sealing members 11 and 13 prevent gas (fluid) from leaking to the outside of the valve case 1.

  The valve body 3 is fixed to the valve body shaft 2 and is configured to rotate 90 degrees between the open state and the closed state with the valve body shaft 2 as a rotation axis. When the valve body 3 is in the closed state, the periphery of the valve body 3 is in close contact with the ring-shaped seat 15 provided in the valve case 1.

  As shown in FIGS. 1 and 2, the drive shaft 4 is provided on the upper part of the valve body shaft 2 and is connected to the valve body shaft 2 via a connecting portion 5. As shown in FIGS. 2 and 3, the connecting portion 5 includes, for example, a concave portion 22 formed at the upper end of the valve body shaft 2 and a convex portion 41 formed at the lower end of the drive shaft 4. The convex portion 41 is inserted into 22 so as not to be relatively rotatable.

  A cylinder 6 is provided above the drive shaft 4. Although detailed illustration explanation is omitted, a piston rod that moves in the horizontal direction by, for example, air pressure is provided in the cylinder 6, and the movement of the piston rod in the horizontal direction rotates the drive shaft 4 via the transmission mechanism. It is configured to be transmitted as an action. The configuration in which the operation of the cylinder 6 (piston rod) is transmitted as the rotation operation of the drive shaft 4 is described in, for example, Japanese Utility Model Publication No. 2-541. The cylinder 6 and the transmission mechanism serve as driving means in the present invention.

  The automatic opening / closing valve X of the present embodiment further includes a detection means 7. The detection means 7 is for detecting whether or not the valve body shaft 2 is in the open position or the closed position. For example, the detection means 7 is connected to the detection section 71 fixed to the valve body shaft 2 and the bracket 16 via the bracket 16. And a proximity switch 72 fixed to the case 1. Examples of the proximity switch 72 include an inductive proximity switch that detects the approach of a metal due to the influence of an external magnetic field, a capacitive proximity switch that detects the presence of a metal and a non-metal object, and an ultra-high speed that detects the approach of an object by reflection of sound. Examples include a sound wave proximity switch and a photoelectric proximity switch that detects the approach of an object by light reflection. In the present embodiment, a case where the proximity switch 72 is configured as an inductive proximity switch will be described as an example.

  The detection unit 71 is made of a metal rod, and is firmly fixed to a band 73 surrounding the valve body shaft 2 in the circumferential direction by screwing or welding. The band 73 is fixed to the valve body shaft 2 by tightening both ends thereof with bolts 74.

  The proximity switch 72 is arranged at a position where the detection unit 71 faces and approaches the valve body shaft 2 when the valve body shaft 2 takes the open position and the closed position, and is provided at two positions 90 degrees apart in the rotation direction of the valve body shaft 2. ing. When the detection unit 71 approaches and approaches the proximity switch 72, the distance L between the detection unit 71 and the proximity switch 72 is about 2 to 4 mm.

  The cylinder 6 and the proximity switch 72 are linked with a control device (not shown). The cylinder 6 operates based on a control signal from the control device, and the operation of the cylinder 6 causes the drive shaft 4 to rotate with a predetermined torque, for example. And the valve body shaft 2 connected with the drive shaft 4 reciprocates between an open position and a closed position, and the opening / closing operation | movement of the valve body 3 is performed automatically. In the control device, the number of times the valve body shaft 2 reciprocates between the open position and the closed position is recorded as the number of operations.

  When the valve body 3 rotates from the closed state to the open state or from the open state to the closed state with the valve body shaft 2 as the rotation axis, the detection unit 71 provided on the valve body shaft 2 also moves simultaneously and approaches the proximity switch 72. Come on. When the detection unit 71 faces the proximity switch 72 and approaches the open position or the closed position, the proximity switch 72 detects the approach of the detection unit 71 and outputs a detection signal to the control device. In the control device, based on the detection signal from the proximity switch 72, the time until the valve body shaft 2 rotates from the open position to the closed position or the valve body shaft 2 rotates from the closed position to the open position. Is recorded as the operating time. The operating time is measured with an accuracy of, for example, 1/20 second or less. Then, along with the opening / closing operation of the valve body 3, the operation time is measured for each operation frequency and recorded in the control device.

  The automatic opening / closing valve X having the above-described configuration is used by being provided at the entrance / exit part of each adsorption tower, for example, in an apparatus for performing gas separation by the PSA method performed using the adsorption tower.

  Next, the usage status and maintenance management method of the automatic opening / closing valve X will be described.

  In the gas separation by the PSA method, the gas flow in each adsorption tower is repeatedly switched in a predetermined cycle. Therefore, the automatic opening / closing valve X needs to be frequently opened and closed. After the automatic opening / closing valve X is newly installed or maintained, the operation time (initial operation time) is relatively long during the first operation (initial operation). That is, at the initial stage of operation, it takes time for the valve body 3 to bite into the seat 15 or the tightening of the seal member 13 of the valve body shaft 2 is stiff and the movement is slow, and the operation time is long. If the opening and closing of the valve body 3 is continued, the sliding contact portion gradually wears, and the opening and closing of the valve body 3 becomes smooth, and the operation time gradually decreases as the number of operations increases. The operating time eventually converges to be substantially constant and becomes stable. If the valve body 3 continues to be opened and closed, the cylinder 6 is damaged, or the connecting portion 5 between the drive shaft 4 and the valve body shaft 2 is loosened, resulting in a phenomenon that the operation time becomes extremely long. Can occur.

  FIG. 4 is a graph showing an example of the relationship between the total number of operations of the valve body shaft 2 and the operation time from closing to opening. Using an automatic on-off valve X configured as a φ600mm butterfly valve, the valve body shaft 2 is moved once from the closed position to the open position and once from one position to the closed position. The valve was opened and closed repeatedly with this one reciprocating opening / closing operation being performed once. In FIG. 4, the operation time from the closed position to the open position of the valve body shaft 2 at each operation number is shown.

  As understood from FIG. 4, when the number of operations of the valve body shaft 2 is relatively small (within about several hundred thousand times), the change rate of the operation time (change in operation time) at a predetermined number of operations relative to the initial operation time Rate) is relatively large, and as the number of operations of the valve body shaft 2 increases, the rate of change in the operation time at a predetermined number of operations relative to the initial operation time becomes relatively small. As described above, when the number of operations of the valve body shaft 2 increases, the change rate of the operation time gradually decreases, and the operation time converges to a certain value shorter than the initial operation time.

  In the maintenance management method for the automatic opening / closing valve X of the present embodiment, when the number of operations is 300,000, the operation change rate is in the range of more than 10% and 60% or less, and the number of subsequent operations is 100,000. When the operating time change rate is 10% or less, it is determined that the maintenance time is reached. For example, when the initial operation time is 1.9 seconds, 10% of 1.9 seconds is 1.9 × (10/100) = 0.19 seconds, and 60% of 1.9 seconds is 1.9. Since x (60/100) = 1.14 seconds, the change width of the operation time with respect to the initial operation time at the time of 300,000 times is in the range of more than 0.19 seconds and not more than 1.14 seconds. Thereafter, it is determined that maintenance is required when the change width of the operation time with respect to the initial operation time for every 100,000 operations becomes 0.19 seconds or less.

  In the case shown in FIG. 4, the operation time (initial operation time) at the first operation is 1.9 seconds, and the operation time at the time when the number of operations is 300,000 times is, for example, 0.8. 8 seconds shorter (the change width of the operation time is 0.8 seconds, the change rate of the operation time is 0.8 / 1.9 × 100 = about 42%), and the operation time becomes 0.00 at the next 100,000 operations. It is shortened by 1 second (the change width of the operation time is 0.1 second, and the change rate of the operation time is 0.1 / 1.9 × 100 = about 5%). Then, the operation time from closing to opening is stabilized toward the direction of convergence to 1.0 second, and when the total number of operations is 530,000, the operation time increases rapidly, and the operation time is initially The operating time was 2.8 seconds, which was longer than the operating time of 1.9 seconds. This rapid increase in the operation time is considered to be caused by the rattling of the cylinder 6 and the connecting portion 5.

  It has been empirically known that the operating time gradually decreases and converges to a certain value as the number of operations of the valve body shaft 2 increases. Since it varies depending on various conditions such as the difference in size of the valve X and individual differences, it is often difficult to predict a value that the operation time converges.

  On the other hand, according to this maintenance management method, if the measured operation time of the valve body shaft 2 is managed, the timing at which the operation time converges and stabilizes can be grasped, and the maintenance time is predicted in advance. be able to.

  In the case shown in FIG. 4 described above, the operating time change rate when the number of operations is 300,000 is about 42% (range of more than 10% and not more than 60%), and the next number of operations is 100,000. Since the change rate of the operation time is about 5% (10% or less), it is determined that the maintenance time is reached after a total of 400,000 operations. On the other hand, unlike the case shown in FIG. 4, for example, the change rate of the operation time at the time when the number of operations is 300,000 times is smaller than the case shown in FIG. The operating time change rate may exceed 10%. In this case, if the operation time change rate at the next operation frequency of 100,000 is 10% or less, it is determined that the maintenance operation time is reached when the total operation frequency is 500,000.

  FIG. 5 is a graph showing another example of the relationship between the total number of operations of the valve body shaft 2 and the operation time from closing to opening. In the case shown in FIG. 5, the operation time at the first operation (initial operation time) is 1.9 seconds, and the operation time at the time when the number of operations is 300,000 times is, for example, 0.8. 6 seconds shorter (change time of operation time is 0.6 seconds, change rate of operation time is 0.6 / 1.9 × 100 = about 31.6%). It is shortened by 0.2 seconds (the change width of the operation time is 0.2 seconds, and the change rate of the operation time is 0.2 / 1.9 × 100 = about 10.5%). In this case, since the operating time change rate at 100,000 times from 300,000 times to 400,000 times has exceeded 10%, the maintenance time has arrived when the total number of times of operation is 400,000 times. It is determined that it is not. Further, the operation time change rate at the next operation count 100,000 is monitored. In the case shown in FIG. 5, the operation time is shortened by 0.05 seconds at the next operation number of 100,000 (the change width of the operation time is 0.05 seconds, and the change rate of the operation time is 0.05 / 1). .9 × 100 = about 2.6%). In this case, the operation time change rate at 100,000 times from 400,000 times to 500,000 times is about 2.6% (10% or less). It is determined that

  The detection unit 71 is fixed to the valve body shaft 2, and the operating time of the valve body shaft 2 is measured by detecting the rotational position of the detection unit 71. According to the configuration in which the detection unit 71 is fixed to the valve body shaft 2 in this way, the movement of the valve body 3 can be accurately grasped, and even if rattling occurs due to mechanical wear, the valve body 3 (valve The operating time at the time of opening and closing the body shaft 2) can be measured accurately. This is preferable for accurately predicting the maintenance time.

  Further, in the maintenance management method for the automatic opening / closing valve X of this embodiment, when the valve body 3 (valve body shaft 2) repeats the opening / closing operation, the operation time of the valve body shaft 2 is a predetermined set time (for example, initial operation). When the time is over, the cylinders 6 are actuated so as to close all the valve bodies 3 of the automatic open / close valves X by the control signal from the control device. According to such a method, even when maintenance is not performed even after the maintenance time has passed, or when an unexpected malfunction occurs in the automatic open / close valve X, all the automatic open / close valves X are urgently used. By closing the valve body 3, the gas separation operation by the PSA method can be safely stopped.

  As described above, as the number of operations of the valve body shaft 2 increases, the operation time of the valve body shaft 2 converges to a certain time shorter than the initial operation time. For this reason, if the set time used as the conditions at the time of emergency closing of the valve body 3 is made into the initial operation time, the automatic on-off valve X can be closed at an appropriate timing.

While specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention. The specific shape and material of each part of the automatic opening / closing valve used in the present invention are not limited to the above embodiment.

In the above embodiment, the case where the automatic opening and closing valve as eccentric butterfly valve has been described as an example, this invention is limited rather than may be configured as a centric butterfly valve, also You may comprise as other types of valves, such as a ball valve.

X Automatic open / close valve 1 Valve case 2 Valve body shaft 3 Valve body 4 Drive shaft 5 Connecting portion 6 Cylinder 7 Detection means 11 Seal member 12 Flange 13 Seal member 14 Flange 15 Seat 16 Bracket 21 Retainer 22 Recessed portion 41 Convex portion 71 Detection portion 72 Proximity switch 73 Band 74 bolt

Claims (4)

It said rotatable valve body shaft about the axis, a valve body fixed to the valve body shaft, a drive shaft connected via a connecting portion to the valve body shaft, by rotationally driving the drive shaft Driving means for automatically rotating the valve body by opening and closing the valve body shaft between an open position and a closed position, and whether or not the valve body shaft is in the open position or the closed position A method for maintaining and managing an automatic open / close valve comprising:
The number of times the valve body shaft reciprocates between the open position and the closed position is the number of operations,
Using the detection result of the detection means, for each number of operations, the time until the valve body shaft rotates from the closed position to the open position, or rotates from the open position to the closed position. Measure the time to reach as operating time,
When the initial operation time is the initial operation time, the maintenance time when the rate of change (operation time change rate) at which the operation time decreases for a predetermined number of operations relative to the initial operation time is less than the predetermined value A method for maintaining and managing an automatic on-off valve, characterized in that it is determined to be present. The operating time change rate when the number of operations is 300,000 times is in the range of more than 10% and 60% or less, and the operating time change rate after every 100,000 operation times is 10% or less. The maintenance management method for an automatic on-off valve according to claim 1, wherein it is determined that the maintenance time is reached . The automatic opening and closing according to claim 1 or 2, wherein when the operation time becomes equal to or longer than a set time, the valve body shaft is rotated to the closed position by the operation of the driving means to close the valve body. Valve maintenance management method. 4. The maintenance management method for an automatic opening / closing valve according to claim 3, wherein the set time is the initial operation time .

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