JPH0469320B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an initial air exhaust valve in steam piping and from a steam trap.

The usefulness of exhausting air from steam piping is well known, and generally an air exhaust valve with a built-in bimetal is used to detect the difference in temperature between the air and steam and the bimetal automatically opens the valve. There was something that opened and closed.

Bimetals usually expand and contract proportionally depending on the temperature, but this type of air exhaust valve in particular uses an inverted bimetal. The reason for this is that in the type that responds to temperature, when the temperature rises, the valve opening is throttled, making it impossible to secure the normal discharge flow rate. Moreover, if the valve is slightly opened, the valve will close due to the pressure caused by the flow of fluid, and the valve will close regardless of the set temperature.

On the other hand, if the valve is of the inverted type, the valve opening can remain fully open until the set temperature, allowing fluid to be effectively discharged, and the valve will close instantly at the desired temperature. Therefore, an inverted bimetal is used.

Prior Art FIG. 2 shows a high-pressure steam trap incorporating the above-mentioned inverted bimetal.

A main body 1 and a lid 2 are fastened together with bolts and nuts 4 with a gasket 3 interposed therebetween. The main body 1 has an inlet 5 and an outlet 6, and has a condensate storage chamber 7 in the center.
The float 8 is housed in a free state. A valve seat 12 having a main valve port 9 is attached to the diagonally lower part inside the main body so as to come into contact with the float 8 when the valve is closed. The main valve port 9 communicates with the outlet 6 through an outlet passage 13. Valve seat 12
An outlet cover 14 is fastened to the main body at the rear with bolts and nuts 15.

Above the float 8 is a float cover 16 that prevents the float 8 from floating and protects the float 8 from the impact force of inflowing condensate, and a screen 17 is disposed above the float cover 16. An exhaust valve 19 is screwed onto the upper part of the inner wall 18 of the main body. This exhaust valve 19 is shown in FIG. 3 and will be described below.

An exhaust valve seat 22 having an exhaust valve port 21 is attached to the center of the holder 20, a disc bimetal 24 with an exhaust valve body 23 facing it is placed, and a bimetal cover 26 with a screen 25 attached to the inlet side is snap-springed. Fix it at 27.
The bimetal 24 curves in the direction shown in the figure when the temperature is low, and reversely curves in the direction opposite to the direction shown in the figure when the temperature is high.

To explain the operation, low-temperature air at the initial stage of startup is quickly discharged from the exhaust valve port 21 toward the outlet 6 because the bimetal 24 is in the curved state shown.

Next, when high-temperature condensate and steam flow into the condensate reservoir chamber 7 from the inlet 5, the bimetal 24 is reversely curved in the opposite direction to that shown in the figure, and the exhaust valve body 23 is pressed against the exhaust valve seat 22 by the bending force of the bimetal 24. Sit down and close the exhaust valve port 21. The float 8 rises and falls according to the level of condensate in the reservoir chamber 7, opens the valve port 9, and discharges the condensate to the outlet 6 side.

Problems to be Solved by the Invention The above bimetal also employs an inverted type for the reasons mentioned above. In order to ensure a sufficient exhaust flow rate, it is necessary to provide a sufficient gap between the exhaust valve seat 22 and the exhaust valve body 23. To do this, it was necessary to increase the diameter of the disk due to design considerations. Therefore,
If such a shape were to be stored in the trap body, the space between the screen 17 and the lid 2 would become large as shown in FIG. 1, resulting in a large trap overall.

Therefore, the technical problem of the present invention is to create a compact exhaust valve having an inverted valve mechanism that can ensure a sufficient exhaust flow rate.

Means for Solving the Problems The technical means of the present invention taken to solve the above problems is to form a valve port in a main body having an inlet and an outlet to communicate between the two, and a valve forming the valve port. A valve body having a valve stem and normally biased by a spring in the valve-closing direction is arranged on the inlet side of the seat, and a stepped portion having a different diameter is formed on the valve stem so as to fit with the stepped portion. A first structure in which a locking member is arranged and contracts at high temperatures and expands at low temperatures to bias the valve body in the valve opening direction against the biasing force of the spring.
A bimetal is disposed in engagement with the valve shaft, and the locking member is biased to maintain the valve body in an open state until the desired high temperature is reached. When the desired temperature is reached, the bimetal expands and the locking member A second bimetal is disposed to release the biasing force on the valve body and close the valve body.

Function: When the temperature is low at the beginning of startup, the first bimetal expands and its force overcomes the spring, separating the valve body from the valve seat and discharging the initial air. As the high temperature fluid gradually flows in, the first bimetal gradually contracts. At this time, the spring tries to expand, but the locking member fits into the step provided on the valve stem, and the locking member
Since the bimetal is energized, the valve body and the valve port have an initial gap and are opened. When the fluid temperature further increases, the first bimetal fully contracts, and the second bimetal bends in the radial direction, causing the locking member to come off the stepped portion of the valve shaft, and the spring force that expands at this time causes the valve to close instantly. .

When the fluid becomes cold, the second bimetal tries to return to its original state and presses the locking member, but since it has come off the stepped part of the valve stem, the valve stem is opened by the expanding first bimetal. Move in the direction of the valve. When the temperature further decreases, the first bimetal expands, overcomes the spring force, and reaches the desired valve opening position, the locking member fits into and locks the stepped portion of the valve shaft.

Effect: Even without using a disk-shaped inverted bimetal, a large lift can be obtained, allowing a small exhaust valve to be made, and the steam trap that houses it can also be made smaller overall.

The first bimetal is used because it shrinks at high temperatures, so no matter what kind of high-temperature fluid it is used with, no overload is applied to the bimetal itself when the valve is closed, and it can be used for a long time.

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

An inlet 50 and an outlet 51 are coaxially formed in a main body 53 via a valve port 52. Snap springs 56 and 57 are attached to the inner wall of the main body, and a cylindrical sleeve 58 is sandwiched between them. A plate-shaped second bimetal 59 is spirally wound around the outer peripheral surface of the sleeve 58 and fixed at one end with a screw 60. A hole 61 is opened in a portion corresponding to the outer peripheral wall of the sleeve 58 at the other end, and a steel ball 64 is placed therein. The valve body 5 is placed inside the cylinder of the sleeve 58.
The valve shaft 54 provided with the number 5 is slid.

The valve stem 54 consists of a large diameter portion 62 and a small diameter portion 54,
The boundary is defined by the sleeve 58 when the valve body is fully open.
It is located at the hole 61 provided in the hole 61, and a stepped portion 63 is formed there. Valve body 55 and snap spring 57
A spring seat 65 is interposed between the valve body 55 and the valve port 52.
A spring 66 is arranged so as to bias it toward the side.

On the other hand, at the rear of the valve shaft 62, a double spiral type first bimetal 68 is provided between the stopper 67 and the snap ring 56 so as to contract at high temperatures and expand at low temperatures. This bimetal is a plate-shaped bimetal that has been coiled into a larger spiral shape, and is characterized by the fact that it generates a large amount of force when it expands and contracts.

The exhaust valve of this embodiment uses a threaded portion 69 formed at the outlet of the main body 53 in place of the exhaust valve 19 in FIG. 2.

The action is as follows. At the time of startup, the first bimetal 68 is expanded as shown in the figure, the spring 66 is in a contracted state, and the valve port 52 is opened to discharge low-temperature air. At this time, the second bimetal 59 is in a state of holding down the steel ball 64, which is fitted into the stepped portion 63 of the valve shaft 54.

As the fluid temperature rises, the first bimetal 68 contracts, and the force of the spring 66 expanding causes the valve element to attempt to close the valve port. However, the steel ball 64 mentioned above
3 and is locked, so the valve port remains fully open. If the temperature rises further, the second bimetal 5
9 is bent in the radial direction and the steel ball 64 becomes free,
As a result, the fitting portion comes off and the valve body 55 closes the valve opening by the spring 66.

When the temperature becomes low, the first bimetal 68 expands and tries to open the valve. The second bimetal 59 returns to its original position and works to press down the steel ball 64. Then, at the point where the stepped portion 63 returns to the hole 61, the steel ball 64 fits into the stepped portion 63 and locks the valve stem.

By attaching the second bimetal 59 at an arbitrary temperature, the valve closing temperature can be selected.

It goes without saying that the exhaust valve of this embodiment may be used by being directly attached to the steam main pipe in addition to the above-mentioned usage examples.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an air exhaust valve according to an embodiment of the present application, FIG. 2 is a sectional view of a steam trap incorporating a conventional exhaust valve, and FIG. 3 is a sectional view of a conventional exhaust valve. 50...Inlet, 51...Outlet, 52...Valve port,
53... Main body, 54, 62... Valve stem, 55... Valve body, 58... Sleeve, 59... Second bimetal, 63... Step portion, 64... Steel ball, 66... Spring, 68... ...First bimetal.

Claims (1)

[Claims] 1. A valve port is formed in the main body having an inlet and an outlet to communicate the two, and on the inlet side of the valve seat forming the valve port,
A valve body having a valve stem and always biased by a spring in the valve-closing direction is disposed, a stepped portion having a different diameter is formed on the valve stem, and a locking member is disposed so as to fit with the stepped portion. A first bimetal that contracts at high temperatures and expands at low temperatures to bias the valve body in the valve opening direction against the biasing force of the spring is disposed in engagement with the valve shaft until the desired high temperature is reached. A second element that biases the locking member to maintain the valve body in an open state, expands when a desired temperature is reached, releases the biasing force on the locking member, and closes the valve body.
Air exhaust valve from steam atmosphere with bimetal arrangement.