JPH0716959Y2 - Pilot steam trap - Google Patents

Description

[Detailed Description of the Invention] <Industrial field of application> The present invention relates to a steam trap for automatically discharging condensate from a steam-using device or steam pipe, and particularly to a pilot suitable for discharging a large amount of condensate. Formula steam trap.

Depending on the type of equipment using steam, the amount of condensate that the steam trap must discharge can vary from small to large. For discharging a large amount of condensate, a pilot type steam trap, which has a large discharge amount per unit volume of the trap casing, has been conventionally used.

<Prior Art> As an example of a conventional pilot-type steam trap, there is a technology as disclosed in, for example, JP-A-55-112490.

This uses the downward bucket float as a pilot valve to open and close the pilot valve port, and allows the pressure fluid to flow into or close into the pressure chamber formed between the pilot valve and the piston at one end of the pressure responsive main valve to close the pressure responsive main valve. The valve is opened and closed. By opening and closing a small pilot valve port, a large pressure-responsive main valve can be opened and closed, and a large amount of condensed water can be discharged.

<Problems to be Solved by the Present Invention> In the above-mentioned conventional one, there is a problem that the size of the pressure-responsive main valve is limited and a large main valve opening cannot be opened and closed. That is, in the conventional type, the pressure responsive main valve is composed of a main valve that is integrated with a pressure receiving responsive member such as a piston, and the pressure responsive main valve opens against the fluid pressure on the primary side of the main valve. This is because the size of the main valve cannot be made larger than that of the pressure receiving responsive member such as the piston. If the pressure-responsive member such as the piston is made large, the main valve opening can be made large, but the trap casing becomes large.

Therefore, a technical problem of the present invention is to open and close a larger main valve opening to discharge a large amount of condensed water without increasing the size of the trap casing.

<Means for Solving the Problems> The technical means of the present invention taken to solve the above-mentioned problems is to provide a space between the pilot valve and the piston at one end of the pressure-responsive main valve according to the displacement of the pilot valve. In the one that controls the pressure in the formed pressure chamber and opens and closes the pressure-responsive main valve,
The pilot valve is formed of a temperature responsive element, and the displacement of the pilot valve at a desired low temperature is small piston member connected to the pilot valve and the large piston member connected to the pressure responsive main valve, the small piston member and the large piston. It is characterized in that the pressure in the pressure chamber is maintained at a pressure higher than the primary side pressure of the trap by transmitting the pressure to the pressure responsive main valve through the sealed liquid arranged between the members.

<Operation> The pilot valve formed by the temperature responsive element is displaced at a desired low temperature. The displacement of the pilot valve is transmitted to the pressure-responsive main valve via the small piston member, the sealed liquid, and the large piston member. In this case, the force generated by the displacement of the pilot valve is magnified by Pascal's principle and transmitted to the pressure-responsive main valve. The expansion ratio of this force can be appropriately set by the area ratio of the large piston and the small piston. For example, by selecting the displacement force of the pilot valve so that the load per unit area, that is, the pressure obtained by dividing the displacement force of the pilot valve by the effective sectional area of the small piston, is equal to or higher than the primary pressure of the trap, The pressure in the chamber can be raised above the primary pressure of the trap.

<Example> An example showing a specific example of the above technical means will be described.
(See FIG. 1) A steam trap casing is formed by a main body 4 having an inlet 1, a valve chamber 2, and an outlet 3, and an upper lid 5 and a lower lid 6. A screen 7 is arranged between the inlet 1 and the valve chamber 2. Inside the valve chamber 2, a temperature responsive element 8 made of bimetal with a U-shaped cross section
And the pressure-responsive main valve 9 is arranged. The pressure-responsive main valve 9 has an inverted triangular cross section and is provided with an annular main valve seat 17 facing the tapered surface of the lower surface. The valve chamber 2 has an outlet 3 through a main valve seat 17 and a rising passage 18.
Communicate with. The temperature responsive element 8 has a through hole 12 at one end to allow the pilot valve rod 15 to penetrate therethrough, and the fixing rings 13, 1 at both ends.
4 is provided, and the other end is provided with screws 11 through the guide member 10 to the main body 4
Install on. The temperature responsive element 8 and the pilot valve rod 15 form a pilot valve. The pilot valve rod 15 slides up and down in the small piston hole 16 provided in the main body 4 by the deformation of the temperature responsive element 8.

A small piston 20 having a small effective area is arranged in contact with the lower end of the pilot valve rod 15. Further, a large piston 21 having a large effective area is formed below the pressure-responsive main valve 9 via a partition wall 30. The lower surface of the small piston 20 and the lower surface of the large piston 21 are loosely connected via a sealed liquid 22. Packing 23, 24 for sliding is attached to the small piston 20 and the large piston 21. Large piston 21
A coil spring 25 is arranged on the upper part of the valve to urge the pressure-responsive main valve 9 in the valve closing direction. Reference numeral 26 is a communication hole that connects the upper space of the large piston 21 and the rising passage 18. A bolt 31 is provided on the lower lid 6 so that the sealed liquid 22 can be replenished or replaced.

The operation is as follows. Condensate flows in from the inlet 1 and collects in the valve chamber 2. When the temperature of the condensate drops due to heat radiation or the like, the bimetal temperature responsive element 8 is deformed downward (state of FIG. 1). As the temperature responsive element 8 is deformed, the pilot valve rod 15 is displaced downward to push down the small piston 20. The pressure generated by pushing down the small piston 20 acts on the large piston 21 via the sealed liquid 22, causing the pressure-responsive main valve 9 to separate from the main valve seat 17, and the condensed water accumulated in the valve chamber 22 is removed. Discharge to the outlet 3. When condensate is discharged and steam flows into the valve chamber 2, the temperature responsive element 8 is deformed in the opposite direction, the small piston 20 is not pushed down, and no pressure is generated in the sealed liquid 22. The valve 9 is seated on the main valve seat 17 by the elastic force of the coil spring 25 and the fluid pressure in the valve chamber 2 to prevent vapor discharge.

<Effects of the Invention> In the conventional device, the pressure in the pressure chamber cannot be increased above the primary pressure of the trap, and the pressure responsive main valve cannot be made larger than the area of the pressure responsive member such as the piston. However, according to the present invention, the pressure in the pressure chamber can be raised to the primary pressure or higher by the principle of Pascal, and the larger main valve port can be opened and closed without being limited by the size of the pressure receiving responsive member. Therefore, a large amount of condensate can be discharged without increasing the size of the trap casing.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the pilot type steam trap of the present invention. 1: Inlet, 2: Valve chamber 3: Outlet, 4: Main body 8: Temperature responsive element, 9: Pressure responsive main valve 15: Pilot valve rod, 17: Main valve seat 20: Small piston, 21: Large piston 22: Sealed Liquid, 31: bolt

Claims (1)

[Scope of utility model registration request] 1. A pilot valve for controlling the pressure in a pressure chamber formed between a pilot valve and a piston at one end of the pressure-responsive main valve according to the displacement of the pilot valve to open and close the pressure-responsive main valve. Is formed by a temperature responsive element, and the displacement of the pilot valve at a desired low temperature is determined by a small piston member connected to the pilot valve and a large piston member connected to the pressure responsive main valve, and the small piston member and the large piston member. A pilot-type steam trap, characterized in that the pressure in the pressure chamber is maintained at a pressure higher than the primary side pressure of the trap by transmitting the pressure to the pressure-responsive main valve via a sealed liquid disposed therebetween.