JPH0424724B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a pressure reducing valve used for reducing the pressure of steam produced in a boiler and sending the reduced pressure to steam-using equipment.

Water vapor condenses when cooled. When air is compressed, water condenses. Therefore, condensed water is always present in steam and compressed air systems. If this condensed water flows into the pressure reducing valve mixed with gas, hunting may occur, wear of the valve portion may be accelerated, or the pressure on the downstream side may rise beyond a set value (shutoff pressure rise).

Prior Art Therefore, the present applicant developed a pressure reducing valve that prevents the inflow of condensed water and proposed it as Utility Model Application No. 59-97855. This system has a swirl vane that swirls the controlled fluid between the inlet of the pressure reducing valve and the main valve port, a steam separation chamber below the swirl vane, and a float-type automatic drain valve at the bottom of the steam separation chamber. is arranged. Then, cover the float of the float type automatic drain valve with a float cover with an opening at the bottom, and make a ventilation hole in the upper peripheral wall of the float cover, so that water flows through the opening at the bottom of the float cover, and internal gas flows through the ventilation hole. It is designed to go inside so that it can be pushed out and replaced.

In this case, when the main valve port opens and swirl occurs, the water surface of the water accumulated at the bottom of the separation chamber becomes concave due to the influence of the swirl, and the water surface at the outer periphery rises. For this reason, it was necessary to make the separation chamber sufficiently elongated so that the separated water would not be transported from the main valve port to the outlet side again.

Means for Solving the Problems The technical means of the present invention taken to solve these inconveniences is to form an inlet, a main valve port, and an outlet in a pressure reducing valve casing, and to create a connection between the inlet and the main valve port. A swirling vane for swirling the controlled fluid is arranged, a steam/water separation chamber is provided below the swirling vane, a float-type automatic drain valve is disposed at the bottom of the steam/water separation chamber, and a float cover with an opening at the bottom is installed. This is a type of automatic drain valve that covers the float and has a ventilation hole approximately in the center of the top of the float cover.

Effect The operation of the above technical means is as follows.

When the main valve port opens, fluid flows from the inlet toward the main valve port. Along the way, it is swirled by swirling vanes, and water droplets in the gas are thrown out and separated from the gas in the center.

Due to the swirling, the pressure in the steam/water separation chamber becomes higher on the outside and lower on the inside. Since the vent hole formed approximately in the center of the float cover is located at the center of the swirling flow, the water flowing into the interior through the lower opening is easily replaced with the gas inside that flows out through the vent hole. Therefore, during swirling, the water level at the bottom of the steam/water separation chamber will drop, and the separated water will not be transported from the main valve port to the outlet again.

The float ascends and descends with the water level inside the float cover, opens and closes the drain valve, and automatically drains water.

Effect of the invention The present invention produces the following unique effects.

With the above-mentioned conventional float cover, in which the ventilation holes are opened in the upper peripheral wall, the water level inside the float cover becomes lower than the outside when the float turns, which delays the floating of the float and the opening of the valve, resulting in a large amount of water remaining. are doing. In the present invention, when the float cover is turned, water on the outside of the float cover is easily sucked into the inside, so that the float rises and the valve opens more easily, and the amount of retained water decreases.

Embodiment (see FIG. 1) An embodiment illustrating a specific example of the above technical means will be described.

The casing of the pressure reducing valve includes a spring case 2 that houses a pressure setting spring, a valve case 4 that has a pilot valve, and a main body 6 that has a main valve 5.
The main body 8 of the separator case forming the steam/water separation chamber 7 and the bottom cover 9 are made of cast metal.

A diaphragm made of a thin metal plate is sandwiched between a spring case 2 and a valve case 4. The space above the diaphragm is connected to the outside air,
The lower space is connected through a passage 33 to the outlet 18 described below.

Adjustment screw 20 on the ceiling wall of spring case 2
Attach and prevent rotation with lock nut 21. The inner end of the adjusting screw 20 contacts the upper end of the pressure setting spring.

The body 6 is formed with an inlet 28 and an outlet 18. The inlet 28 and the outlet 18 are separated by a horizontal wall 29 and connected through a main valve port 30 provided in the wall 29. The main valve 5 is located below the main valve port 30, and its upper end is connected to a piston 31.

The pilot valve is located between the passage 32 leading to the inlet 28 and the passage leading to the space above the piston 31.

The piston 31 slides inside a cylinder 42 attached to the inner periphery of the main body 6, has two annular grooves around the outer periphery, and has a piston ring 43 made of PTFE and a spring 44 arranged inside the piston ring 43. . The piston ring 43 is made of PTFE and has low sliding resistance, reducing wear. Since the piston ring 43 is biased against the inner peripheral surface of the cylinder 42 by a spring 44, the space between the piston 31 and the cylinder 42 can be almost completely sealed. Further, the piston 31 is provided with an orifice 45 that connects its upper surface and lower surface, and a certain amount of fluid on the upper surface of the piston 31 is released from the orifice 45 to control the pressure.

A partition member 46 is arranged in the space below the main valve port 30. The partition member 46 has an almost cylindrical upper part and a double cylindrical lower part. A swirl wing 47 is formed at the upper end between the double cylindrical portions with an inclination of about 30 degrees. A guide shaft 49 for guiding the lower part of the main valve 5 is formed on the central axis of the inner cylindrical portion via three ribs 48.

Expand the bottom end of the inner cylindrical part and drain the water 5
form 0. The outer periphery 51 at the upper end of the inner cylindrical portion is tapered. The partition wall member 46 is integrally formed of lost wax, and its outer cylindrical lower end is placed on the upper end of the main body 8 of the separator case and urged upwardly by a spring 52.
1 is fitted into the protruding tapered surface of the horizontal wall 29, positioned on the central axis, and fixed.

A carbon ring is attached to the outer periphery of the part of the main valve 5 that slides inside the guide shaft 49 and fixed with a snap spring, and a collar 54 with a smooth inner surface is interposed between it and the guide shaft 49. Reduce sliding resistance. The valve body 5 and the piston 31 are separate bodies, and each is guided by a guide shaft 49 and a cylinder 42.
Even if both are tilted, they will not get caught. A conical screen 55 is arranged around the outer periphery of the partition member 46.

The main body 8 of the separator case is attached to the main body 6 via a PTFE gasket 56. The main body 8 of the separator case has a shape with a widened bottom, and a bottom cover 9 is attached to the bottom of the main body 8 through a gasket 57 made of PTFE to form a steam/water separation chamber 7 inside. A hollow spherical float 58 made of a thin metal plate and a float cover 59 made of casting to cover it are arranged in the separation chamber 7.

The float cover 59 has an inverted cup shape, and has legs 60 extending downward and outward from the front and back sides of the paper in FIG. It is fixed by sandwiching it between the bottom lids 9. The center upper part of the float cover 59 is formed to protrude upward, and a ventilation hole 61 is opened there. The upper end opening of the vent hole 61 is located in a low pressure region at the center of the swirling flow.

The water accumulated in the separation chamber 7 enters inside from the lower part of the float cover 59, and the gas inside is sucked out through the vent hole 61 and replaced. Since the float cover 59 is made of cast metal, it is sturdy and will not be deformed or damaged by swirling flow or water hammer. Since the ventilation hole 61 is provided in the upper center, the pressure is lower in the center due to the swirling flow, and gas is easily sucked out, improving the air and water replacement efficiency. Furthermore, since the vent hole 61 portion protrudes upward, gas is more likely to come out.

The bottom cover 9 is provided with a float seat 62 for determining the lowering position of the float 58 and a drain valve port 63. A drain valve port 63 is opened and closed by a float 58 to automatically drain water accumulated in a separation chamber 7 from a drain port 64.

The operation of the above embodiment will be explained.

The outlet side pressure acts on the lower surface of the diaphragm, and the spring force of the pressure setting spring acts on the upper surface.
The spring force of the pressure setting spring can be adjusted by rotating the adjusting screw. When the pressure on the outlet 18 side decreases, the diaphragm is bent by the spring force of the pressure setting spring to open the pilot valve.
When the pilot valve opens, the high-pressure fluid on the inlet 28 side flows into the upper surface of the piston 31 through the passage 32 and the piston 31 is displaced downward, which causes the main valve 5 to also be displaced downward and closes the main valve port. 30 is opened. By opening the main valve port 30, high-pressure fluid on the inlet 28 side is supplied to the outlet 18 side, and
Side pressure is restored. When the pressure on the outlet 18 side recovers to a predetermined value, the diaphragm balances with the spring force of the pressure setting spring and returns to its original position, and the pilot valve closes, so that the pressure on the top surface of the piston 31 is no longer supplied and the pressure is removed from the orifice 45 to the outlet 18. By escaping to the side, the downward displacement force is lost, and the main valve 5 closes due to the pressure difference with the outlet 18 side. In this way, when the pressure on the outlet 18 side falls below a predetermined value, the high pressure fluid on the inlet 28 side is replenished, thereby maintaining the outlet 18 side in a predetermined reduced pressure state.

When the main valve port 30 is opened, gas containing condensed water passes through the screen 55 from the inlet 28 and is swirled by the swirl vanes 47 of the partition member 46 . The water droplets are thrown outward and impinge on the inner wall of the main body 8 of the separator case and flow down along it. The gas reaches the space below the main valve port 30 through the inner opening of the drainer 50 of the partition member 46 .

The water accumulated in the gas separation chamber 7 is automatically discharged from the drain valve port 63 to the drain port 64 by the action of the float 58.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a pressure reducing valve according to an embodiment of the present invention. 7...Air-water separation chamber, 18...Outlet, 28...Inlet, 30...Main valve port, 47...Swirl vane, 58...
Float, 59...Float cover, 61...Vent hole, 64...Drain port.

Claims (1)

[Claims] 1. An inlet, a main valve port, and an outlet are formed in the pressure reducing valve casing, and a swirling vane for swirling the controlled fluid is arranged between the inlet and the main valve opening, and an air-water separation chamber is provided below the swirling vane. A float-type automatic drain valve is placed at the bottom of the separation chamber, the float of the float-type automatic drain valve is covered with a float cover with an opening at the bottom, and a ventilation hole is provided approximately in the center of the top of the float cover to reduce pressure with a drain valve. valve.