JPS5934771Y2 - Seal mechanism of valve stem sliding part in valve - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sealing mechanism for a sliding portion of a valve stem in a valve that reduces the sliding resistance of the valve stem and eliminates the need to apply grease to the sliding portion.

Conventionally, in various valves, the mechanism for opening and closing the valve port that communicates the primary side and the secondary side by sliding the valve stem is to attach a valve body that opens and closes the valve port to the end of the valve stem, and to slide the valve stem into a cylinder on the bulkhead. The valve stem is movably supported and the valve opening and closing operations are performed by sliding the valve stem up and down, and the sliding portion of the valve stem is sealed with a rubber O-ring.

However, since the rubber O-ring has a large sliding resistance, it is compensated for by applying grease, etc. However, if the grease runs out after long-term use, the sliding resistance increases and the valve opens and closes smoothly. In addition to complicating operations, the grease to be applied is highly adhesive, making it difficult to apply.

In view of these drawbacks, the present invention provides a valve in which a valve port that communicates the downstream side and the secondary side is opened and closed by a valve body attached to a valve stem, in which a concave groove is formed on the outer periphery of the sliding part of the valve stem. A sealing mechanism for the sliding part of the valve stem is provided in which a piston ring made of fluororesin is fitted into a concave groove via an O-ring to solve the above-mentioned drawbacks, and the following is an embodiment of the present invention. To explain this based on the drawings, Fig. 1 shows an example in which a pressure reducing valve is implemented with a sealing mechanism for a valve stem sliding part in a valve according to the present invention, and A is a pressure reducing valve main body, which includes a valve body 1 and a spring. Hollowed out from the cover 2, the valve box 1 is divided by a partition wall 7 into a primary pressure chamber 4 communicating with the inflow port 3 and a secondary pressure chamber 6 communicating with the discharge port 5,
The primary pressure chamber 4 and the secondary pressure chamber 6 are communicated through a valve port 8 which is provided through the partition wall 7.

Reference numeral 9 denotes a diaphragm sandwiched between the valve box 1 and the spring cover 2, and a diaphragm shell 10 placed on the upper surface of the diaphragm 9 and an adjustment screw 11 screwed into the upper part of the spring cover 2 for vertical adjustment. An adjustment spring 12 is press-fitted between the two.

Reference numeral 13 denotes a valve stem, on the upper part of which a sliding part 15 is formed which corresponds to the cylinder 14 opened coaxially above the valve port 8, and on the outer periphery of the sliding part 15 a groove 16 is formed. An annular piston ring 18 made of fluororesin is fitted into the groove 16 via an O-ring 17, and the O-ring 17 presses the piston ring 18 in the outer circumferential direction to bring it into close contact with the cylinder 14. A rod 13 is inserted through the rod 13 so as to be able to slide vertically, and the upper end of the valve rod 13 is attached to the diaphragm 9 so as to be interlocked with the diaphragm 9 which is displaced according to pressure fluctuations in the secondary pressure chamber 6.
The lower end extends through the valve port 8 to the lower part of the secondary pressure chamber 6, and is fitted with a valve body 20 which is attached to and separates from a valve seat 19 formed at the lower periphery of the valve port 8 to open and close the valve port 8. A pressure regulating spring 24 is press-fitted between the valve body cover 21 and the cap body 23, which are tightened and fixed with nuts 22 through the body cover 21.

In the figure, 25 is a check valve provided in the flow path of the primary pressure chamber 4;
6 is a strainer, 27 is a strainer cap, and 28 is a negative pressure operated valve.

The pressure reducing valve main body A is configured such that the diaphragm 9 is displaced in response to fluctuations in the pressure on the secondary side, thereby causing the valve stem 13 to slide up and down, and automatically adjusting the degree of opening of the valve body 20 with respect to the valve port 8. This is to maintain the pressure at a constant set pressure.

In short, the present invention is a valve in which a valve port for communicating the downstream side and the secondary side is opened and closed by a valve body attached to a valve stem, in which a concave groove 16 is formed on the outer periphery of the sliding portion 15 of the valve stem 13, and Since the piston ring 18 made of fluororesin is fitted into the concave groove 16 via the O-ring 17, the frictional resistance is smaller than the material characteristics of the piston ring 18, so that the sliding operation of the valve stem 13 is always smooth. There is no need to apply grease to the sliding part 15, and the double structure of the piston ring 18, which acts as a direct sealing member, and the O-ring 17, which makes the piston ring 18 press against the cylinder 14, eliminates the need to apply grease. Therefore, if the sliding part becomes worn, only the piston ring 18 needs to be replaced, and since the piston ring 18 is wrapped around the O-ring 17 so as to apply pressure in the outer circumferential direction, the tightness to the cylinder 14 is improved. The improved sealing properties of the sliding parts can be ensured even when high pressure is applied, and the practical effects are enormous, such as being able to be widely used as a sealing mechanism for the sliding parts of various valves.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a sectional view of a pressure reducing valve, and FIG. 2 is a partially cutaway perspective view of the main part. 13... Valve stem, 15... Sliding part, 16
...Concave groove, 17...O ring, 18.
·····piston ring.

Claims (1)

[Scope of utility model registration request] In a valve in which the opening and closing of the valve port that communicates the primary side and the secondary side is controlled by a valve body attached to the valve stem, a groove is formed on the outer periphery of the sliding part of the valve stem, and an O-ring is fitted into the groove. A seal for a sliding part of a valve stem in a valve, characterized in that a piston ring made of a fluororesin separately formed on the outer periphery of the O-ring is wrapped around the O-ring in such a manner that the O-ring acts elastically in the outer circumferential direction. mechanism.