JPH0738972Y2 - Pressure reducing valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION 1) Field of Industrial Application The present invention relates to a piston portion of a pilot operated pressure reducing valve which is attached to a pipe such as steam or compressed air to keep a fluid pressure on a secondary side at a constant set pressure.

2) Conventional technology Conventionally, as shown in Japanese Patent Publication No. 46-38466, a general piston shape is one in which a column for operating the main valve body is formed in the lower center of the piston.

3) Problems to be solved by the present invention When the high-speed fluid flows through the valve port toward the outlet side, the fluid causes the strut of the piston to incline, which causes the entire piston to incline and catch on the inner wall of the cylinder. Therefore,
The piston and cylinder do not move smoothly, and a stable secondary pressure cannot be maintained.

Also, when the main valve that is in contact with the lower part of the piston tries to close due to the piston getting stuck, it is not possible to make complete contact with the valve seat surface, and the shut-off pressure increase, which is one of the test items showing the performance of the pressure reducing valve, is high. Become.

The technical problem of the present invention is that the piston is kept upright and slides on the inner wall of the cylinder without being affected by the flow of fluid.

4) Technical Means for Solving Problems The technical means of the present invention taken to solve the above problems is to form an inlet, a valve opening, and an outlet in a valve casing, and to face the valve opening. The main valve is arranged so that the main valve cooperates with the piston to open and close the valve opening, and when the piston bottom surface is communicated with the outlet side of the valve opening, the piston is displaced by the main valve. Is provided at the lower part of the piston, and a weight having a larger specific gravity than the material of the piston is provided at the column.

5) Action By providing a weight with a large specific gravity at the bottom of the piston, the center of gravity of the piston is located below the center of the height of the piston. Therefore, when the piston tilts due to the flow of fluid from the valve opening and its center of gravity deviates from the center, a rotational moment acts and the piston returns to the center.

6) Effect Since the piston slides smoothly without being caught in the cylinder, a stable secondary pressure can be supplied.

Further, since the piston does not get caught in the cylinder, even when the main valve that is in contact with the lower part of the piston rises because of the valve closing, it rises without any obstacle and completely contacts and closes the valve.

7) Example An example showing specific means of the present invention will be described.

(See FIGS. 1 and 2) An inlet 2 and an outlet 3 are coaxially formed in a main body 1 and communicated with each other through a valve port 4. Piston 5 whose bottom surface is formed into a hemisphere
Is slidably arranged in the cylinder 6, and the support 7 is connected to the valve port 4
Inside, the projection 9 of the main valve 8 is brought into contact. Almost the entire lower surface of the piston 5 is arranged in communication with the side of the outlet 3 of the valve opening 4.

The piston 5 has grooves on the peripheral wall to form piston rings 10, 11
Then, the tension rings 12 and 13 are fitted from the inside, and the piston ring is stretched outward. The lower surface is formed as a hemisphere, the orifice 37 is opened, and the cylindrical support 7 is provided in the lower center. A weight 14 made of a material having a larger specific gravity than the material of the piston is inserted into the cylinder, and a lid 15 is fitted at the lower end to perform brazing. The material of the piston body is generally made of stainless steel, and the weight is selected from lead, etc., which has the largest specific gravity ratio of the two.

The main valve 8 is disk-shaped and has an annular valve seat surface on its upper surface and abuts against the valve port, and a main valve shaft 16 is formed on its lower surface.

The pressure on the upper surface of the piston 5 is controlled by the pilot valve 17.
The pilot valve 17 is arranged in a primary pressure passage 18 that connects the inlet 2 and the upper space of the piston 5, that is, the piston chamber, and is operated by a tire flam 20 elastically biased by a pressure setting spring 19.
The diaphragm 20 is attached with its outer peripheral edge sandwiched by the flanges 21 and 22, the lower end of the pressure setting spring 19 is in contact with the upper surface via the diaphragm retainer 23, and the upper end of the pilot valve 17 is in contact with the lower surface. The upper space of the diaphragm communicates with the outside air through the passage 24, and the lower space communicates with the outlet 3 through the passage 25. The pressure setting spring 19 is biased by the adjusting screw 26. Adjusting screw
Turning 26 to the left or right changes the elastic force that pushes down the pressure setting spring 19 and the diaphragm 20. Using the elastic force of the pressure setting spring 19 as a reference value, the diaphragm 20 bends according to the secondary pressure acting on the lower surface of the diaphragm 20 to open / close the pilot valve 17.

As a result, the primary fluid pressure is introduced into the piston, the piston 5 is driven and the main valve 8 is displaced, and the fluid at the inlet 2 flows through the valve port 4 to the outlet 3. Then, when the secondary side fluid pressure decreases, the valve port 4 opens, and when the secondary pressure rises, it automatically closes.

In the space below the valve port 4, a draining member 27 having a generally cylindrical shape and a wide lower end is arranged, and a swirl vane 28 is provided on the outer peripheral surface of the middle abdomen thereof. A holder guide 29 is provided inside to insert the main valve shaft 16, and a main valve spring 30 is interposed.

The fluid entering from the inlet 2 swirls around the lower outer periphery of the draining member 27 by the swirl vanes 28, the water droplets are swung out by the centrifugal force and flow down, and the gas passes through the center of the draining member 27 to the valve opening 4. Pass through and exit to exit 3.

A drain valve port 33 communicating with the drain port 32 is formed at the bottom of the drain valve chamber 31. Spherical valve float 35 covered with float cover 34
Is accommodated in a freely displaceable manner. A ventilation hole 36 is formed in the upper portion of the float cover 34.

The valve float 35 floats down along with the water level in the drainage valve chamber 31 to open and close the drainage valve port 33, and automatically drains the water accumulated in the drainage valve chamber 31.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the pressure reducing valve of the present invention, and FIG. 2 is an enlarged sectional view of a piston portion in FIG. 1 ... Main body, 4 ... Valve port, 5 ... Piston 7 ... Strut, 14 ... Weight 17 ... Pilot valve, 20 ... Diaphragm

Claims (1)

[Scope of utility model registration request] 1. A valve casing is provided with an inlet, a valve opening and an outlet, a main valve is arranged facing the valve opening, and the main valve cooperates with a piston to open and close the valve opening. A pressure reducing valve in which almost the entire lower surface of the piston is in communication with the outlet side of the valve opening, and a column for transmitting displacement of the piston to the main valve is provided at the lower part of the piston, and a weight having a specific gravity larger than that of the piston material is provided on the column .