JPH0738845U - Electric valve wear detector - Google Patents

Abstract

(57) [Summary] [Purpose] Detect the occurrence of a change in the relationship between the axial position of the stem and the phase of the rotation direction of the stem nut, and grasp the wear state of the screw based on this. [Structure] A motor-operated valve configured to move a stem 2 in an axial direction by fitting a male screw 2a of a stem 2 and a female screw 3a of a stem nut 3 and rotating the stem nut 3, Stem detecting means 21 for detecting the axial position, stem nut detecting means 22 for detecting the phase of the rotation direction of the stem nut 3 and 22, the outputs of the stem detecting means 21 and the stem nut detecting means 22,
Wear determining means 25 for determining whether or not a change has occurred in the relationship between the output signals from both detecting means. Further, an integration display means 27 is provided for receiving the output signal of the stem detection means 21 and integrating and displaying the number of times the valve has been operated.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a device for detecting when the wear of a screw of a motor-operated valve becomes large to prevent a malfunction.

[0002]

[Prior art]

 When moving up and down the valve body in a conventional motor-operated valve, a male screw cut into a stem made of a material with a relatively high hardness such as stainless steel and a female screw of a stem nut made of a material with a low hardness such as a copper alloy are fitted together. A structure in which the stem is moved in the axial direction by rotating the stem nut is widely known.

[0003]

[Problems to be solved by the device]

 By the way, in the above-mentioned conventional motor-operated valve, the screw may be worn during repeated up-and-down operations, and if this wear progresses, the screw may eventually break and the motor-operated valve may not be opened or closed. . For this reason, for motor operated valves that are operated at high frequency, it was necessary to periodically disassemble the valve and measure the amount of screw wear.

The present invention has been made paying attention to such a point, and its purpose is to provide a motor-operated valve that is normally operated to open and close according to its intended use. It is to continuously detect the relationship between the axial position of the stem and the phase of the rotation direction of the stem nut to grasp the wear state of the screw, and if necessary, for example, the above-mentioned stem axial position and stem nut rotation direction. When the relationship with the phase of exceeds the condition according to the allowable value of screw wear, an alarm is issued to notify.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, claim 1 is a motor-operated valve configured such that a male screw of a stem and a female screw of a stem nut are fitted and the stem nut is rotated to move the stem in an axial direction. Is assumed. On the other hand, it receives the outputs of the stem detecting means for detecting the axial position of the stem, the stem nut detecting means for detecting the phase of the stem nut in the rotation direction, and the stem detecting means and the stem nut detecting means. And a wear determining means for determining whether or not a change has occurred in the relationship between the output signals from the both detecting means. According to the second aspect of the present invention, in addition to the above configuration, an integrated display means for receiving the output signal of the stem detection means and cumulatively displaying the number of operating times of the valve is provided.

[0006]

[Action]

 In claim 1, when the screws are worn, the fitting relationship between the male thread of the stem and the female thread of the stem nut is deviated, for example, when the valve is fully opened, and the output signal from the stem detecting means and the stem nut detection are detected. The relationship with the output signal from the means changes from the relationship before the wear, and this fluctuation is detected by the wear determining means. According to the second aspect, the number of times the valve has been operated is cumulatively displayed on the cumulative display means by using the output signal of the stem detecting means.

[0007]

【Example】

 Examples will be described below. In FIGS. 1 and 2, reference numeral 1 denotes a sleeve that is rotatably provided on the motor-operated valve main body and is rotationally driven by an electric motor. Reference numeral 2 is a stem connected to the valve body, and a male screw 2a is formed on the upper end of the stem. Reference numeral 3 denotes a cylindrical stem nut which is fitted in the sleeve 1 and rotates in the same manner as the sleeve 1 by the spline 4, and has a female screw 3a formed on the inner wall and fitted with the male screw 2a. Therefore, the stem 2 is axially moved by rotating the stem nut 3 via the sleeve 1 by the electric means. In this case, when the stem nut 3 makes one revolution, the screw advances one pitch, but with the basic screw, that is, a screw without wear, when the valve is in a fixed position, an arbitrary point in the axial direction of the stem 2 and the circumference of the stem nut 3 One point always has the same positional relationship, in other words, the axial position of the stem 2 and the rotational phase of the stem nut 3 have a fixed relationship. However, as the wear progresses, the relationship between the axial position of the stem 2 and the phase of the stem nut 3 in the rotational direction is deviated due to play.

A cylindrical lock nut 5 is fitted into and fixed to the sleeve 1, and the stem nut 3 is constrained so as not to move up and down. A stem cover 6 is fitted and fixed to the upper flange 7 of the drive device on the upper portion of the electric valve body.

A stud bolt 11 is erected on the upper end of the stem 2, and a vertical movement detection nut 12 illustrated in the figure of the abacus ball shape in the drawing has a vertical position via a spacer 13 or the like. It is fixed by a nut 14 that fits into the stud bolt 11 so as not to change. On the other hand, a rotation detecting ring 15 is rotatably attached to the upper end of the lock nut 5 and fixed by a set screw 16 in a desired direction. As shown in FIG. 3, the rotation detecting ring 15 is composed of a cylindrical main body 15a and a shielding wall 15b which is erected at the upper end thereof over a range of, for example, 180 degrees out of the entire circumference of 360 degrees.

A stem detecting means 21 for detecting the axial position of the stem 2 and a stem nut detecting step 22 for detecting the phase of the stem nut 3 in the rotation direction are fixed to the stem cover 6. There is. These two detecting means 21 and 22 are both magnetic proximity sensors, and output an ON signal when an object approaches within a predetermined distance, and do not output an ON signal otherwise. The stem detecting means 21 is positioned so that an ON signal is output by the proximity of the vertical movement detecting nut 12 when the valve is fully opened with the basic screw. Therefore, the stem detecting means 21 outputs the ON signal only when the valve is fully opened, and otherwise does not output the ON signal. Further, in the stem nut detecting means 22 as well, when the valve is fully opened in the basic screw, as shown in FIG. 3, substantially central portions in the circumferential direction of the inner wall of the shielding wall 15b of the rotation detecting ring 15 are opposed to each other. Position so that the ON signal is not output. Therefore, when the phase of the shielding wall 15b in the rotating direction shifts when the valve is fully opened due to the wear of the screw, if the phase shift deviates by 90 degrees or more in the forward rotation direction or the reverse rotation direction, the stem nut detecting means 22 shields. The outer wall of the wall 15b approaches and outputs an ON signal. The output signals of the stem detecting means 21 and the stem nut detecting means 22 are inputted to the wear judging means 25 composed of an electric circuit, and the wear judging means 25 is outputted as an ON signal from both of the detecting means 21 and 22. Sometimes it outputs a wear alarm signal. An alarm device 26 is connected to the wear determining means 25 and receives a wear alarm signal to issue an alarm. Further, the wear determining means 25 is connected to an integrated display meter (integrated display means) 27 including, for example, an electromagnetic counter, so that the number of operating times of the valve can be integratedly displayed from the output signal of the stem detecting means 21. ing. Specifically, for example, one opening / closing operation of the valve is cumulatively displayed by counting one output signal for two times.

Next, the operation of the above embodiment will be described. For a basic screw that is not worn, the stem detecting means 21 outputs an ON signal when the valve is fully opened, but the stem nut detecting means 22 does not output an ON signal, and therefore the wear judging means 25 outputs a wear alarm signal. If not, the alarm device 26 does not operate.

Then, as the screw wears, the phase of the shielding wall 15b of the rotation detection ring 15 in the rotation direction shifts when the valve is fully opened, and the phase shift is 90 degrees in the forward or reverse direction. When the deviation is more than one degree, the outer wall of the shield wall 15b comes close to the stem nut detecting means 22 and an ON signal is output. Therefore, the wear determining means 25 outputs a wear alarm signal, and the alarm device 26 operates to issue an alarm.

Therefore, in the above embodiment, since an alarm is issued when the wear of the screw exceeds the allowable range, it is not necessary to periodically disassemble the valve to measure the amount of wear of the screw. It is possible to prevent problems such as inability to open and close the motor operated valve due to screw breakage.

Further, since the total number of times the valve has been operated is cumulatively displayed by the total indicator 27, it is possible to perform maintenance such as lubrication of the screw portion or replacement of the stem nut by utilizing the number of valve operations and the stem nut wear data. It can be done properly.

In the above embodiment, the stem detecting means 21 is configured to detect that the stem 2 and the vertical movement detecting nut 12 are in the valve fully open position where the movement of the stem 2 and the vertical movement detecting nut 12 is stopped. The position is not limited, and the position may be detected at any one point during the stroke of the valve. This makes it easier to set the detection position, and in general, it is more advantageous to detect the position at the point immediately before full closure in order to downsize the wear detecting device. In addition, the shielding wall 15b is erected over a range of 180 degrees out of 360 degrees around the circumference, and the phase shift in the rotation direction of the stem nut 3 when the valve is fully opened is 90 degrees or more in the forward or reverse direction. Although it is configured to give an alarm when it shifts, this angle setting is arbitrary, and these values are only examples. Generally, a trapezoidal screw of JISB0221 or JISB0222 is often used as a stem screw for a motor-operated valve. At this time, as shown in FIG. The angle can be adjusted. Further, the stem detecting means 21 and the stem nut detecting means 22 may be set so that the ON signal is not output when the object approaches, and at that time, the wear determining means 25 outputs the ON signal from both the detecting means 21 and 22. It may be configured to output a wear warning signal when the warning is no longer generated. In short, the up / down movement detecting nut 12 may be configured to output a wear alarm signal when the up / down movement detecting nut 12 is close to the stem detecting means 21 and the phase difference of the rotation detecting ring 15 in the rotation direction exceeds a predetermined angle. Further, in the embodiment, the detecting means 21 and 22 are both magnetic proximity sensors, but they may be other proximity sensors, for example, optical sensors.

[0016]

[Effect of device]

 As described above, according to the wear detecting device for a motor-operated valve of claim 1, the output signal of the stem detecting means for detecting the axial position of the stem and the output of the stem nut detecting means for detecting the phase in the rotation direction of the stem nut. Since it determines whether or not a change has occurred in the relationship with the signal, if a warning is given, for example, when the change exceeds the allowable range, problems such as inability to open / close the motor-operated valve due to screw breakage can be prevented. be able to. Further, since the wear detecting device for a motor-operated valve according to claim 2 cumulatively displays the number of operating times of the valve by using the output signal of the stem detecting means, the number of operating times of the valve and the wear data of the stem nut are used for the screw operation. Maintenance such as lubrication of parts and replacement of stem nuts can be properly performed.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of an embodiment,

FIG. 2 is a cross-sectional view of the embodiment shown with a part cut away;

FIG. 3 is a perspective view of a rotation detection ring of the embodiment.

[Explanation of symbols]

 1 Sleeve 2 Stem 2a Male Thread 3 Stem Nut 3a Female Thread 11 Stud Bolt 12 Vertical Motion Detection Nut 14 Nut 15 Rotation Detection Ring 16 Set Screw 21 Stem Detection Means 22 Stem Nut Detection Means 25 Wear Detection Means 26 Alarms 27 Integrated Indicators (Totalization display means)

Claims (2)

[Scope of utility model registration request] 1. A motor-operated valve configured to move a stem in an axial direction by fitting a male screw of a stem and a female screw of a stem nut and rotating the stem nut,
Stem detecting means for detecting the axial position of the stem, stem nut detecting means for detecting the phase in the rotation direction of the stem nut, output from the stem detecting means and stem nut detecting means, and outputs from both detecting means A wear detecting device for a motor-operated valve, comprising: wear determining means for determining whether or not a signal relationship has changed. 2. A wear detecting device for a motor-operated valve according to claim 1, further comprising integrated display means for receiving and displaying an output signal from the stem detecting means and displaying cumulatively the number of times the valve has been operated.