JP2000065220A - Control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify processing operations, and surely control a very small flow rate in a high state of accuracy, and provide a control valve capable of easily coping with the control of an intended very small flow rate. SOLUTION: Each spiral groove is provided for the plug head 17 of a valve plug 15 provided in the inside of a body 10, the depth of each aforesaid spiral groove is formed so as to be shallower as the groove goes to its root side from the tip end side of the plug head 17, and each spiral groove formed out of a single streak or plural ones shall be provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control valve for controlling a minute flow rate.

[0002]

2. Description of the Related Art In a control valve of this type, a plug head is moved up and down with respect to a seat ring provided in a body to change a flow passage area formed in an opening between the seat ring and the plug head, thereby changing fluid flow. This is a valve having a structure for adjusting the minute flow rate.

In particular, various examples of the shape of the plug head as shown in FIGS. 7 to 9 have been known. FIG. 7 shows a case where the plug head 1 is formed in a conical shape, and the flow rate is adjusted while fitting the plug head 1 to the seat ring 2. FIG. And the plug head 3 is moved up and down on the seat ring 5. Further, FIG.
A V-shaped groove 7 is formed in the outer periphery of the plug head 6 along the flow path by notching, and the plug head 6 is moved up and down on the seat ring 8.

[0004]

However, the shape of the plug head 1 shown in FIG. 7 has the drawback that not only is it difficult to adjust the minute flow rate, but rather cavitation and erosion tend to occur.

To solve this drawback, the plug heads 3 and 6 are formed as shown in FIGS. 8 and 9. The plug heads 3 and 6 have the notch 4 and the V-shaped groove 7. A milling process for processing while visually checking was required, and it was troublesome to achieve the processing accuracy. The present invention
It has been developed to solve the conventional problems, and its purpose is to simplify the processing operation, to ensure accurate adjustment of the minute flow rate, and to adjust the desired minute flow rate. It is an object of the present invention to provide a control valve which can easily cope with the above.

[0006]

SUMMARY OF THE INVENTION To achieve the above object, the present invention is a control valve having a spiral groove formed in a plug head of a valve plug provided in a body.

In this case, it is preferable that the depth of the spiral groove is formed shallower from the tip end side of the plug head to the root side, and that one or more spiral grooves are provided on the outer peripheral surface of the plug head. I do.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a control valve according to the present invention will be specifically described with reference to FIGS. FIG.
A seat ring 12 having a valve port 11 is mounted at a central position in a body 10 having outflow and inlet ports 10a and 10b, a bonnet 13 is further fixed to an upper portion of the body 10, and a packing 14 mounted inside the bonnet 13 is provided.
The valve plug 15 is provided so as to be able to move up and down via the.

A cylindrical plug head 17 is formed at the lower end of the plug 15, and a clockwise or counterclockwise spiral groove 18 is provided along the circumferential direction of the outer peripheral surface of the plug head 17. The processing of the spiral groove 18 can be automatically performed by a single processing machine such as an NC lathe in which the plug head 17 is processed, so that highly accurate processing can be performed and the processing time can be reduced. .

3 and 4, the spiral groove 18 has a triangular cross section and four thread-shaped grooves.
Moreover, the cutting depth of the spiral groove 18 is formed to be shallower from the tip end side of the plug head 17 toward the root side. When the cut depth of the spiral groove 18 is formed in this manner, the precision of minute flow rate adjustment can be further improved.

FIG. 5 shows an example in which two spiral grooves 18 are provided in the plug head 17. By increasing or decreasing the number of spiral grooves 18, the Cv value of the control valve can be proportionally increased or decreased. . Further, by changing the cutting depth of the spiral groove 18, the cross-sectional shape such as a triangle or a trapezoid, and the dimensions of the spiral groove 18, the minute flow rate can be adjusted according to the purpose of use.

The spiral groove 18 in the present embodiment is formed by a screw machine such as an ordinary NC lathe.
When the number of lines is changed, for example, the Cv value in the case of one line is 0.045, the Cv value in the case of two lines is 0.090,
It was confirmed that the Cv value in the case of the strip could be 0.135. As described above, when the spiral groove 18 is arbitrarily changed according to the implementation, the flow rate can be proportionally set according to the purpose of use.

In the figure, reference numeral 19 denotes a yoke for holding the actuator of the control valve, and 20 denotes a male thread provided at the upper end of the plug 15. An output shaft of the actuator is screwed to the male thread 20. The plug 15 is moved up and down.

Although the plug head 17 in the above example is formed in a cylindrical shape, the present invention is not limited to this. By forming the plug head 17 in the conical portion 21 as shown in FIG. Can be adjusted according to the flow rate.

Next, the operation of the above embodiment will be described.
When fluid is supplied from the inlet 10a to the outlet 10b of the body 10, the plug 15
Is moved up and down, a minute communication portion is formed between the valve port 11 of the seat ring 12 and the plug head 17 via the spiral groove 18 so that the fluid flows.

In this case, the spiral groove 18 is formed by cutting out the length of the spiral groove 18 in the outer peripheral surface of the plug head 17, and the groove depth is formed shallower from the upstream side to the downstream side of the plug head 17. Therefore, the flow rate can be proportionally increased as the valve opening of the plug head 17 is increased,
The flow rate can be finely adjusted, while the flow rate can be proportionally reduced as the valve opening is reduced. Furthermore, by appropriately selecting the shape, length or number of spiral grooves 18 according to the implementation, a control valve capable of proportionally adjusting the flow rate according to the purpose of use can be obtained.

[0017]

As is apparent from the above description, according to the present invention, the processing time can be shortened and the processing accuracy can be improved. Thus, a control valve which enables the above can be obtained.

Further, the present invention has an excellent effect that a control valve having a required minute flow rate can be reliably manufactured as required.

Further, the shape, size, length and number of spiral grooves can be appropriately changed, and the length of the spiral groove can be increased as compared with the prior art. Adjustment is possible, and different Cv values can be reliably accommodated.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a control valve according to the present invention.

FIG. 2 is an enlarged sectional view showing a plug head and a seat ring in FIG. 1;

FIG. 3 is a partial front view showing an example of a plug head according to the present invention.

FIG. 4 is an enlarged cross-sectional view of FIG.

FIG. 5 is an enlarged cross-sectional view showing another example of the plug head.

FIG. 6 is an enlarged cross-sectional view showing still another example of the plug head.

FIG. 7 is an explanatory front view showing an example of a conventional plug head of a control valve.

FIG. 8 is an explanatory front view showing another example of a conventional plug head.

FIG. 9 is an explanatory front view showing still another example of the conventional plug head.

[Explanation of symbols]

 10 Body 11 Valve Port 12 Seat Ring 15 Valve Plug 17 Plug Head 18 Spiral Groove

Claims (3)

[Claims] 1. A control valve, wherein a spiral groove is provided in a plug head of a valve plug provided in a body. 2. The control valve according to claim 1, wherein a depth of the spiral groove is formed to be shallower from a tip end side of the plug head toward a root side. 3. The method according to claim 1, wherein one or more spiral grooves are provided.
Or the control valve according to 2.