JP7368172B2 - Rotary valve cleaning method and valve system - Google Patents

Description

The present invention relates to a rotary valve cleaning method and valve system.

Various valves are used in plants. For example, in the process of manufacturing resin products such as plastics, the pipes that supply raw materials to polymerization equipment and the pipes that take polymerized products out of the polymerization equipment are equipped with balls as shown in Figures 5A and 5B. An on/off control valve is used.

This on/off control valve includes a valve body 201, an inflow passage 202 and an outflow passage 203 formed in the valve body 201, a valve body 204 disposed at the center inside the valve body 201, and a valve body 204 that is connected to the valve body 201. 201 and a valve shaft 205 for rotational operation from the outside.

The valve body 204 is rotatably disposed in a plane orthogonal to the axis of the valve body 201, has a substantially spherical shape, and has a through passage 206 formed of a through hole therein. The through passage 206 is formed so that its tube axis is perpendicular to the axis of the valve shaft 205 . Further, the valve body 204 has a recess 204a formed in the center of the upper surface, and a lower end 205a of the valve shaft 205 is fitted into the recess 204a while being prevented from rotating.

When the valve shaft 205 is rotated around the axis and the valve body 204 is rotated to align the pipe axis of the through flow path 206 with the pipe axes of the inflow flow path 202 and the outflow flow path 203, as shown in FIG. 5B. Then, the inflow channel 202 and the outflow channel 203 communicate with each other via the through channel 206, and the on/off control valve becomes on (fully open). When the valve element 204 is rotated 90 degrees about the axis of the valve shaft 205 in this ON state, the inflow passage 202 and the outflow passage 203 are separated by the valve element 204, as shown in FIG. 5A. , the on/off control valve is in the off (fully closed) state.

Japanese Patent Application Publication No. 2003-113948

However, this type of rotary valve has a problem in that malfunction may occur due to contamination such as foreign matter. For example, water scale due to calcium carbonate, calcium sulfate, silica, etc. contained in water accumulates in the pocket 211 between the outer circumferential surface of the valve body 204 and the inner circumferential surface of the valve body 201, and the valve body 204 inhibits rotation. In order to remove this dirt such as water scale, cleaning is performed by flowing a cleaning liquid into the channel. However, in the on/off control valve using a rotary valve, even if cleaning is performed, there is a situation where dirt cannot be completely removed.

The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to more reliably remove dirt from an on/off control valve caused by a rotary valve.

A rotary valve according to the present invention includes a rotary valve, an operating device configured to operate rotation of a valve body of the rotary valve, and a control signal configured to receive a control signal to control operation of the valve body by the operating device. and a control unit configured to receive an instruction for a cleaning process and send a control signal for half-opening the rotary valve to the positioner.

In the above configuration example of the valve system, when the valve system is fully open, the pocket portion formed between the outer circumferential surface of the valve body and the inner circumferential surface of the valve body, and the inflow passage and outflow passage of the rotary valve rotate. When the valve is half-open, communication occurs through the passage through the valve body.

Further, the rotary valve cleaning method according to the present invention includes a first step of partially opening the rotary valve, and a second step of flowing a cleaning liquid while the rotary valve is half-open.

An exemplary configuration of the rotary valve cleaning method described above includes a third step of fully opening the rotary valve and flowing the cleaning liquid, and the first step is performed subsequent to the third step.

In one configuration example of the rotary valve cleaning method described above, the method further includes a fourth step of fully closing the rotary valve after the second step, and a fifth step of fully opening the rotary valve after the fourth step.

In the above configuration example of the rotary valve cleaning method, the second step includes cleaning the pocket portion formed between the outer circumferential surface of the valve body of the rotary valve and the inner circumferential surface of the valve body in the fully open state; The inflow channel and the outflow channel are communicated with each other via the through channel of the valve body with the rotary valve half open, and the cleaning liquid is allowed to flow.

As described above, according to the present invention, since the cleaning liquid is flowed while the rotary valve is half-open, dirt on the on/off control valve caused by the rotary valve can be more reliably removed.

FIG. 1 is a configuration diagram showing the configuration of a valve system according to an embodiment of the present invention. FIG. 2 is a flowchart for explaining a rotary valve cleaning method according to an embodiment of the present invention. FIG. 3A is a sectional view showing a state of a ball valve undergoing a rotary valve cleaning method according to an embodiment of the present invention. FIG. 3B is a cross-sectional view showing the state of the ball valve undergoing the rotary valve cleaning method according to the embodiment of the present invention. FIG. 3C is a cross-sectional view showing the state of the ball valve undergoing the rotary valve cleaning method according to the embodiment of the present invention. FIG. 4A is a characteristic diagram showing a valve signature before cleaning to explain the cleaning effect. FIG. 4B is a characteristic diagram showing the valve signature after cleaning according to the embodiment to explain the cleaning effect. FIG. 5A is a sectional view showing the configuration of an on/off control valve using a ball valve. FIG. 5B is a cross-sectional view showing the configuration of an on/off control valve using a ball valve.

Hereinafter, a valve system according to an embodiment of the present invention will be described with reference to FIG. This valve system is a system for implementing a rotary valve cleaning method, and includes a rotary valve 101, an operating device 102, a positioner 103, and a control section 104.

The rotary valve 101 is, for example, a ball valve or a plug valve. The operating device 102 operates the rotation of the valve body of the rotary valve 101. The positioner 103 receives the control signal and controls the operation of the valve body by the operating device 102. For example, the positioner 103 converts the control signal into air pressure, and the operating device 102 operates the rotation of the valve body according to the air pressure supplied from the positioner 103.

The control unit 104 receives the instruction for a cleaning process and transmits a control signal to the positioner 103 to half-open the rotary valve 101. The operating device 102, which is controlled by the positioner 103 that has received the control signal for half-opening the rotary valve 101, operates the valve body of the rotary valve 101 to bring the rotary valve 101 into a half-open state. In this half-open state, when the valve body is fully open, the pocket formed between the outer circumferential surface of the valve body and the inner circumferential surface of the valve body, and the inflow passage and outflow passage of the rotary valve 101 are connected to the valve body. communicate through the through flow path.

Next, a method for cleaning a rotary valve according to an embodiment of the present invention will be described with reference to FIG.

First, in step S101, the rotary valve 101 is fully opened, and in step S102, the cleaning liquid is flowed through the fully open rotary valve 101 (third step). The cleaning liquid is, for example, water. Next, in step S103, the rotary valve 101 is half-opened (first step), and in step S104, the cleaning liquid is allowed to flow through the half-opened rotary valve 101 (second step). Next, in step S105, the rotary valve 101 is fully closed (fourth step), and then, in step S106, the rotary valve 101 is fully opened (fifth step).

Hereinafter, the fully open, fully closed, and half open states of the rotary valve 101 will be described with reference to FIGS. 3A, 3B, and 3C. Note that FIGS. 3A, 3B, and 3C show cross sections of the rotary valve 101 in a plane perpendicular to the valve shaft.

In the fully open (ON state) state, as shown in FIG. 3A, the pipe axis of the through passage 113 of the valve body 112 arranged at the center inside the valve body 111, the pipes of the inflow passage 114 and the outflow passage 115 are connected to each other. The axes coincide with each other, and the inflow channel 114 and the outflow channel 115 communicate with each other via the through channel 113. When fully opened, the inflow channel 114, the through channel 113, and the outflow channel 115 are filled with the cleaning liquid 121. However, when fully opened, the pocket portion 118 between the inner circumferential surface 116 of the valve body 111 and the outer circumferential surface 117 of the valve body 112 is separated from each of the flow paths described above, and the cleaning liquid 121 is in the pocket portion 118. Don't get into it.

When the valve body 112 is rotated 90 degrees around the axis of the valve stem in the fully open state described above, the inflow passage 114 and the outflow passage 115 are separated by the valve body 112, as shown in FIG. 3B. Then, the rotary valve 101 becomes fully closed (off state). In this fully closed state, the through channel 113 and the pocket portion 118 communicate with each other, and the cleaning liquid 121 also enters the pocket portion 118 .

Conventionally, in cleaning the on-off control valve, the cleaning liquid 121 was flowed and the cleaning liquid 121 was allowed to enter the pocket part 118 by switching between fully open and fully closed as described above, and the pocket part 118 was cleaned with the cleaning liquid 121. . In this manner, in cleaning by switching between fully open and fully closed, the state in which the cleaning liquid 121 acts on the pocket portion 118 is limited to when the pocket portion 118 is fully closed. In this state, the amount of cleaning liquid 121 acting on the pocket portion 118 is limited to the total volume of the through flow path 113 and the pocket portion 118 when fully closed, and a sufficient cleaning effect in the pocket portion 118 cannot be obtained. This was discovered through intensive study by the inventors.

In contrast to the above-mentioned conventional art, as shown in FIG. 3C, by opening half-open, the pocket portion 118 communicates with the inflow channel 114 and the outflow channel 115 via the through channel 113. As a result, in the half-open state, the cleaning liquid 121 enters the pocket part 118, and the inflow passage 114, the through passage 113, the outflow passage 115, and the pocket part 118 are filled with the cleaning liquid 121. In this half-open state, the amount of cleaning liquid 121 acting on the pocket part 118 is not limited to the total volume of the through flow path 113 and the pocket part 118 in the fully closed state. By continuing to flow the cleaning liquid 121, the state in which new cleaning liquid 121 acts on the pocket portion 118 continues. As a result, by half-opening, the cleaning effect of the cleaning liquid 121 in the pocket portion 118 can be further enhanced compared to conventional cleaning. Note that half-open does not strictly mean an opening of 50%, but an opening other than fully open or fully closed, and the pocket portion 118, the inflow channel 114, and the outflow channel 115 are connected to the through channel 113. It means the degree of opening that establishes a relationship of communication through.

Next, the effect of cleaning will be explained. When the valve body is rotated by continuously changing the air pressure output to the operating device, the cleaning status can be determined based on the results (valve signature) of measuring the air pressure and the amount of displacement (travel) of the valve body. You can check it. Malfunctions due to contamination in rotary valves appear in the valve signature as unstable micro-movements.

If the rotary valve is contaminated, for example, as shown in FIG. 4A, both the valve signature when turning on the rotary valve (a) and the valve signature when turning off the rotary valve (b) , unstable tremors are occurring.

When cleaning is performed using the rotary valve cleaning method according to the embodiment due to the above-mentioned dirt generation state, as shown in FIG. 4B, both the valve signature (a) and the valve signature (b) are unstable. It can be seen that there is no more slight movement, and that most of the dirt has been removed.

As described above, according to the present invention, since the cleaning liquid is flowed while the rotary valve is half-open, dirt on the on/off control valve caused by the rotary valve can be more reliably removed.

It should be noted that the present invention is not limited to the embodiments described above, and many modifications and combinations can be made within the technical idea of the present invention by those having ordinary knowledge in this field. That is clear.

101...Rotary valve, 102...Operator, 103...Positioner, 104...Control unit.

Claims (2)

A valve body, a valve body disposed at the center of the valve body and having a through passage formed of a through hole therein, an inflow passage, and an outflow passage, and when fully open, the outer circumferential surface of the valve body and the A pocket portion is formed between the inner circumferential surface of the valve body, and when the pocket portion is in a half-open state, the pocket portion and the inflow channel and the outflow channel communicate with each other via the through-flow channel, and the pocket portion is in a half-open state. Here, a method for cleaning a rotary valve in which the cleaning liquid cannot flow from the inflow channel through the pocket portion to the outflow channel,
a first step of partially opening the rotary valve;
A method for cleaning a rotary valve, comprising: a second step of flowing a cleaning liquid while the rotary valve is half-open. A valve body, a valve body disposed at the center of the valve body and having a through passage formed of a through hole therein, an inflow passage, and an outflow passage, and when fully open, the outer circumferential surface of the valve body and the A pocket portion is formed between the inner circumferential surface of the valve body, and when the pocket portion is in a half-open state, the pocket portion and the inflow channel and the outflow channel communicate with each other via the through-flow channel, and the pocket portion is in a half-open state. The rotary valve does not allow the cleaning liquid to flow from the inflow channel through the pocket portion to the outflow channel ;
an operating device configured to operate the rotation of the valve body of the rotary valve;
a positioner configured to receive a control signal and control the operation of the valve body by the operating device;
A control unit configured to receive an instruction for a cleaning process and send a control signal for half-opening the rotary valve to the positioner.

Images