JPH08312817A - Suction preventing valve - Google Patents

Abstract

PURPOSE: To provide a suction preventing valve provided with a function for shutting down a flow passage when a fluid outlet side becomes in a negative pressure condition. CONSTITUTION: A vale seat 2a is arranged on one end side of a hollow valve main body 2, a valve body 6 is brought in pressure contact with the inner side of the valve seat 2a through a compressed spring 5, the end surface of a fluid inlet 3a abuts on the valve body 6, and also a casing 3 on which a flow passage 3c communicated with a fluid outlet 3b is formed is formed on the outer side of the valve main body 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suction preventive valve which is inserted into a water supply line of a boiler or the like to prevent the can from becoming full when the boiler has a negative pressure while the boiler is stopped.

[0002]

2. Description of the Related Art A check valve 31 inserted in a conventional water supply line or the like has a fluid inlet 33a and a fluid outlet 33b formed in a valve body 33 accommodating a valve body 32, as shown in FIG. A valve seat 33d is formed in the flow passage 33c on the fluid inlet 33a side, and the valve body 32 is pressed against the valve seat 33d via a compression spring 34. Therefore, the fluid inlet 33a
The compression spring 34 is compressed by the pressure fluid flowing from
By opening the valve 32, the fluid flows out from the fluid outlet 33b. Then, when the fluid supply from the fluid inlet 33a is stopped, the action of the compression spring 34 and the back pressure are applied to the valve 32, so that the valve body 32 is brought into pressure contact with the valve seat 33d to prevent the reverse flow of the fluid from the fluid outlet 33b side. It is configured to do.

By the way, in the conventional check valve 31 inserted into the water supply line 36 of the boiler 35 shown in FIG. 5, the inside of the can 37 becomes negative pressure while the boiler 35 is stopped, and the check valve 31 is compressed. The spring 34 may be compressed and water may be supplied from the water supply line 36 to fill the can body 37 with water. Therefore, as a countermeasure against this, the compression spring coefficient of the check valve 31 is increased to overcome the negative pressure. Also,
A vacuum break valve (not shown) may be installed in the steam piping to take measures. However, if the spring coefficient of the compression spring is increased, it is necessary to increase the capacity of the water supply pump 38, which causes a problem such as an early decrease in pump capacity. On the other hand, the vacuum break valve has problems such as corrosion of the water and water surface due to air flowing into the can body 37, vapor leakage from the break valve, etc., and the price of the break valve is high and the cost increases.

[0004]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a suction prevention valve having a function of shutting off a flow path when the fluid outlet side has a negative pressure. It is a thing.

[0005]

The present invention has been made in order to solve the above-mentioned problems, and a valve seat is provided at one end of a hollow valve body, and a compression spring is provided inside the valve seat. The valve body is brought into pressure contact with the valve body, the end face of the fluid inlet is brought into contact with the valve body, and a casing having a flow path communicating with the fluid outlet is provided outside the valve body.

[0006]

According to the present invention, the compression spring is compressed by the pressure fluid flowing from the fluid inlet, and the fluid flows through the gap between the valve seat and the valve body and flows out from the fluid outlet. On the other hand, when the fluid outlet side has a negative pressure, the valve body is sucked to the negative pressure side, and the valve body and the end surface of the fluid inlet are brought into contact with each other, so that the inflow of fluid is blocked.

[0007]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a first embodiment of the present invention, in which a casing 3 is provided outside a valve body 2 of the suction prevention valve 1, and a fluid inlet 3a, a fluid outlet 3b and a flow passage 3c are formed in the casing 3. However, the valve body 2 is arranged in the substantially central portion of the casing 3. The valve body 2 is
A hollow cylindrical valve seat 2a is formed on one end side (fluid inlet side), a spring seat 2b is provided on the other end side, and an air chamber 4 is formed. The air chamber 4 and the valve body are formed. A through hole 2c communicating with the inside of 2 is provided. A valve body 6 provided with a compression spring 5 and a spring receiving seat 6a is inserted inside the valve seat 2a of the valve body 2 by an appropriate means, and the valve body 6 is pressed against the valve seat 2a via the compression spring 5. I am letting you. The downstream side of the fluid inlet 3a is extended by a predetermined length, and the end face of the fluid inlet 3a is brought into contact with the valve body 6. Reference numeral 7 is a drain remover provided in the air chamber 4.
The area ratio between the pressure receiving surface of the fluid inlet 3a of the valve body 6 and the pressure receiving surface of the flow passage 3c is preferably 1 or more with respect to the pressure receiving surface 1 of the fluid inlet 3a.

The operation when the suction prevention valve 1 having the above-mentioned structure is inserted into, for example, the water supply line 17 of the boiler 8 shown in FIG. 2 will be described. The suction prevention valve 1 is inserted upstream of the check valve 31 inserted in the water supply line 17. The boiler 8 shown in FIG. 3 is provided with a burner 9 for heating, and a blower 10 sends combustion air to the burner 9. A fuel supply line 11 is connected to the burner 9, and a fuel pump 12 and a fuel solenoid valve 13 are inserted in this line. And the combustion ON-OFF is the boiler 8
Control is performed by the controller 15 based on a signal from the pressure detector 14 that detects the vapor pressure in the can. That is, the combustion of the burner 9 is stopped when the steam pressure inside the can exceeds the high set pressure, and the combustion of the burner 9 is started when the low set pressure is cut off. Reference numeral 16 is a water level detector for detecting the water level in the boiler can. Based on the signal of this detector, a water level control device appropriately controls the water supply pump 18 in the water supply line 17.
Is turned on and off to keep the water level in the can at a constant level.

Water is supplied while the boiler 8 is in operation by depressing the valve body 6 of the suction prevention valve 1 by the discharge pressure of the water supply pump 18 to form a U-shaped flow path to stop the water supply pump 18. When the pressure is balanced, the flow passage is closed by the action of the compression spring 5. When the boiler 8 is stopped for a long time at night after the boiler 8 is stopped and the inside of the can becomes negative pressure due to coldness at night or the like, the water in the water supply line 17 is sucked, but the suction prevention valve is used. 1 cuts off the water supply. That is, when the inside of the casing 3 of the suction prevention valve 1 is under negative pressure, the valve body 6 is attracted to the valve seat 2a of the valve body 2 and pressed by the action of the compression spring 5. Cut off the inflow of water. Therefore, it is not necessary to increase the compression spring coefficient of the conventional check valve 31 and to attach a vacuum breaking valve or the like in the steam pipe, and it is possible to prevent suction at the time of negative pressure relatively inexpensively. The air chamber 4 is a preliminary chamber when water leaks from the fluid inlet 3a into the valve body 2 and is appropriately drained from the drainage 7.

FIG. 3 shows a second embodiment of the present invention. The same members as those of the first embodiment are designated by the same reference numerals, and the duplicated description will be omitted. In the embodiment of FIG. 3, the valve body 2 is
The casing 3 has an integral structure, and a protrusion 3d is provided between the fluid inlet 3a and the fluid outlet 3b to block the flow path. Valve seats 2a are provided at predetermined locations on the fluid inlet 3a side and the fluid outlet 3d side, respectively, and a predetermined valve body 2 is formed so as to intersect with the valve seat 2a. The valve seat 2a
And the lower surface of the protruding portion 3d are formed on the same surface. The air chamber 4 is provided on the lower peripheral wall of the valve body 2 by appropriate means.
A lid member 19 provided with is detachably provided. A spring seat 19a is provided in the center of the inside of the lid member 19,
A conduction hole 19b is formed in the center of the spring seat 19a. Then, the valve body 6 having the spring seat 6a and the guide portion 6b is slidably inserted into the valve body 2, and the compression spring 5 is inserted between the spring seat 6a and the spring seat 19a. To insert the valve element 6 into the valve seat 2a and the protrusion 3
It is configured to be pressed against the lower surface of d.

The second embodiment has the merit that the flow path is not complicated as compared with the first embodiment, but the discharge pressure from the water supply pump 18 is applied to only one side of the valve body 6 when water is supplied. As shown in FIG. 3, a guide 6b is attached to the valve body 6 to prevent the valve body 6 from tilting. The operation of the suction prevention valve 1 is substantially the same as that of the first embodiment, and therefore its explanation is omitted.

[0012]

As described above, according to the present invention, the valve seat is provided at one end of the hollow valve body, and the valve body is pressed against the inside of the valve seat via the compression spring. Since the suction prevention valve has a structure in which the end face of the fluid inlet is brought into contact with and a casing having a flow path communicating with the fluid outlet is provided outside the valve body, when the fluid outlet side has a negative pressure, Since the valve body is pressed against the end surface of the fluid inlet to close it, water on the water supply side is not sucked.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a first embodiment of a suction prevention valve embodying the present invention.

FIG. 2 is an explanatory diagram when the suction prevention valve of FIG. 1 is inserted into a water supply line of a boiler.

FIG. 3 is an explanatory view showing a second embodiment of the suction prevention valve replacing the embodiment of FIG.

FIG. 4 is an explanatory view of a conventional check valve.

5 is an explanatory diagram when the check valve of FIG. 4 is inserted into a water supply line of a boiler.

[Explanation of symbols]

 1 Suction prevention valve 2 Valve body 2a Valve seat 2c Conducting hole 3 Casing 3a Fluid inlet 3b Fluid outlet 3c Flow path 4 Air chamber 5 Compression spring 6 Valve body

Claims (1)

[Claims] 1. A valve seat 2a is provided on one end side of a hollow valve body 2, a valve body 6 is pressed against the inside of the valve seat 2a via a compression spring 5, and an end surface of a fluid inlet 3a is attached to the valve body 6. And a casing 3 having a flow path 3c communicating with the fluid outlet 3b is provided outside the valve body 2.