JPH0240153B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a flow rate control device that is installed in a gas combustion appliance and has the function of blocking a gas passage and the function of controlling the gas flow rate, that is, the combustion amount according to the amount of electricity supplied. It is related to.

Configuration of conventional example and its problems The functions required of this type of flow rate control device for controlling gas flow rate are: first, a closing function to completely shut off the gas; second, a governor function to keep the gas pressure constant; Thirdly, there is a proportional control function that controls the flow rate.

In order to satisfy this function, conventional flow control devices are equipped with a flow control valve that performs the governor function and proportional control function by varying the setting force of the governor with a built-in diaphragm using electromagnetic force. For the sake of reliability in closing, two closing solenoid valves are connected in series upstream to provide a closing function. However, such a flow rate control device requires two closing solenoid valves, which increases the size and cost of the device. Therefore, in recent years, a flow control device has been proposed in which a closing function is added to the flow control valve and one closing electromagnetic valve is omitted.

Fig. 1 shows this flow rate control device, where 1 is a shutoff valve, 2 is a flow control valve with a shutoff function provided downstream of the shutoff valve 1, and 3 is a nozzle, and gas is ejected from this nozzle 3 to the burner. (not shown) and burns.

The shutoff valve 1 is closed by a valve seat 5 provided in a fluid passage 4, a valve body 6 made of an elastic material that can be freely mounted on the valve seat 5, a plunger 7 integrally provided with the valve body 6, and the valve body 6. It is composed of a spring 8 that applies a valve force, and a coil 9 that attracts the plunger 7 upward against the force of the spring 8 to open the valve.

The flow control valve 2 with a closing function includes a valve body 13 having a primary pressure chamber 10 communicating with the outlet of the closing valve 1, a fluid outlet 11, and a valve seat 12, a valve body 14 provided opposite the valve seat 12, and a valve An elastic body 15 provided at the contact portion between the seat 12 and the valve body 14, an elastic member 16 that biases the valve body 14 in the valve closing direction, and a diaphragm 18 that is integrally provided with the valve body 14 and the membrane plate 17. , has a diaphragm bracket 20 constituting a diaphragm atmospheric pressure chamber 19, and a coil 9', a plunger 7', and a sliding pipe 21 of the plunger 7' are mounted on the upper part of the bracket 20.
It has a drive section 22 that applies an electromagnetic force to the valve body 14 in accordance with the amount of current applied to the coil 9'. The sliding pipe 21 is provided with a reference pressure hole 23 that communicates the back pressure chamber 19 with the atmosphere.

In the above configuration, the valve seat 5 and valve body 6 of the shutoff valve 1 and the valve seat 12 and valve body 14 of the flow rate control valve with a closing function 2 double close the shutoff valve 1 and the flow rate control valve with a closing function. When the valve 2 is energized, gas passes through the shutoff valve 1 and flows into the primary pressure chamber 10, and the pressure on the fluid outlet 11 side, that is, the flow rate, is controlled according to the amount of energization to the coil 9, and it also functions as a gas governor.

However, according to this flow rate control device, if left unattended after controlling the flow rate, components in the gas remaining in the primary pressure chamber 10, which is completely isolated from the atmosphere, penetrate and diffuse into the diaphragm 18 made of nitrile rubber or the like. The pressure is released to the atmospheric pressure chamber 19 communicating with the atmosphere through the reference pressure hole 23, and a phenomenon occurs in which the primary pressure chamber 10, which is a closed space, becomes negative pressure.
This phenomenon progresses over time, and as a gas
This is particularly likely to occur when LPG is used. As a result, as shown in FIG. 2, the membrane portion of the diaphragm 18 is reversed from the normal state 18a to the primary pressure chamber 10 and deformed as shown in 18b, and the effective pressure receiving diameter becomes D', which is smaller than the normal state D. Here, the effective pressure receiving diameter of the valve body 14 is set equal to the effective pressure receiving diameter D of the diaphragm 18 in order to obtain the gas governor function, so when the diaphragm 18 is reversed, the effective pressure receiving diameter on the valve body 14 side becomes large and the valve body 14 is moved upward. The lifting force increases,
Even if it communicates with the coil 9', the valve does not open and becomes inoperable. Furthermore, since the membrane portion 18a of the diaphragm 18 is repeatedly reversed, there is a risk of damage. On the other hand, if the shutoff valve 1 is opened and fluid pressure is applied to the primary pressure chamber 10, the diaphragm 18 will be in a normal state. However, when the primary pressure chamber 10 becomes negative pressure, the valve body 6 of the shutoff valve 1 Negative pressure also acts on the valve and the valve closing force increases, so a large force is required to open the valve, leading to an increase in the size of the coil 9 and cost. In the conventional example shown in FIG. 1, a solenoid valve is used as the shutoff valve 1, but a similar phenomenon occurs even if a gas valve or the like is used.

OBJECT OF THE INVENTION The present invention solves the above-mentioned conventional problems.When the primary pressure chamber becomes negative pressure, a flow control valve with a closing function is automatically opened to release the negative pressure, thereby preventing the valve from being unable to open. The purpose of the present invention is to prevent the diaphragm from reversing, thereby improving reliability and downsizing the shutoff valve.

Structure of the Invention In order to achieve this object, a flow rate control device according to the present invention includes a shutoff valve that shuts off a fluid passage, and a shutoff function that is provided downstream of the shutoff valve and has a function of shutting off the fluid passage and controls the fluid flow rate. the flow control valve has a valve seat, a valve body provided opposite to the valve seat, an elastic body provided at a contact portion between the valve seat and the valve body, and the valve body. a biasing element that biases the valve in the valve closing direction; and a biasing element that is integrally provided with the valve body;
and a diaphragm having an effective pressure receiving diameter substantially equal to that of the valve body, a membrane plate provided on the atmospheric pressure chamber side of the diaphragm, and a membrane plate provided on the fluid pressure acting side of the diaphragm, that is, the opposite side of the atmospheric pressure chamber, and having a diameter larger than the effective pressure receiving diameter of the diaphragm. The valve body is composed of a membrane plate having a flange portion having a large pressure-receiving diameter, and a drive portion for operating the valve body.

With this configuration, when the pressure on the fluid acting side of the diaphragm becomes negative, the membrane portion of the diaphragm comes into close contact with the flange portion, and the effective pressure-receiving diameter of the diaphragm becomes larger than that under normal conditions. Therefore, the force that displaces the valve body downward increases, and the valve body is pushed down against the valve-closing force of the biasing element, and the negative pressure is released. When the negative pressure is released, the diaphragm returns to its normal state, so the force of the biasing element causes the valve body to return to the closed state, and the closed state is maintained until the negative pressure is restored again. On the other hand, even if the membrane part of the diaphragm becomes under negative pressure, it is restrained by coming into contact with the flange part, so that it does not turn over and the reliability against damage is improved.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on the drawings.

3 and 4 show an embodiment of the flow rate control device according to the present invention, in which a primary pressure chamber 10 of a diaphragm 18 whose effective pressure receiving diameter is set to be approximately equal to that of the valve body 14 is shown.
That is, the shutoff valve 1, the valve body 14, the diaphragm 18
A flange portion 2 having a shape substantially similar to the membrane portion 18a of the diaphragm 18 and having a pressure-receiving diameter D _f larger than the diaphragm effective pressure-receiving diameter D on the side of the closed space constituted by
The membrane plate 25 provided with the valve body 14 and the diaphragm 1
8. It is provided integrally with the upper membrane plate 17. A curled portion 26 is provided on the periphery of the flange portion 24 to prevent damage to the important membrane portion 18a of the diaphragm 18 and to prevent adhesion to either or both of the facing surfaces of the diaphragm 18 and the flange portion 24. Non-adhesive treatment has been applied.
Here, the non-adhesive treatment for the diaphragm 18 is performed by performing so-called halogen treatment, etc., which causes cracks on the surface of the diaphragm 18 with a halide, and in the case of the flange portion 24, a Teflon (registered trademark) film is provided on the surface. methods (none of which are shown), etc. The other parts are the same as those of the conventional example shown in FIG. 1, so the same symbols are given and the explanation is omitted.

In the above configuration, when the valve is closed, it is doubly closed by the valve seat 12 and valve body 14 of the shutoff valve 1 and the flow control valve with shutoff function 2, and when electricity is applied, gas pressure flows into the primary pressure chamber 10 and the diaphragm 18 Effective pressure receiving diameter D
The flow rate can be controlled according to the amount of current applied, and it also functions as a governor. When the valve is left unattended after closing, the components in the gas remaining in the primary pressure chamber 10 permeate and diffuse into the diaphragm 18 and are released to the atmospheric pressure chamber 19 side communicating with the atmosphere through the reference pressure hole 23, causing the primary pressure chamber 10 to become negative. Membrane part 1 of diaphragm 18 that becomes pressure
8a is in close contact with the flange portion 24 and has the shape of 18c. The effective pressure receiving diameter at this time depends on the pressure receiving diameter D _f of the flange portion 24 and is larger than the effective pressure receiving diameter D of the diaphragm 18 . Since the effective pressure receiving diameter of the valve body 14 is set equal to the effective pressure receiving diameter D of the diaphragm 18 in order to obtain the governor function, the valve body 14 receives a force in the valve opening direction, and when a predetermined negative pressure is reached, the valve body 14 receives a force in the valve opening direction. Elastic member 1 which is a valve closing biasing element of valve body 14
The valve opens against the valve closing force 6, and the primary pressure chamber 10 becomes equal to atmospheric pressure. At atmospheric pressure, diaphragm 1
The membrane portion 8 is restored from 18c to the state of 18a and becomes a valve closed state, and the valve closed state is maintained until the pressure becomes negative again. Note that once the gas remaining in the primary pressure chamber 10 is released, the primary pressure chamber 10 is replaced with air, so that the pressure will not become negative until gas flows into the primary pressure chamber 10 thereafter. On the other hand, when the film part 18a of the diaphragm 18 comes into close contact with the flange part 24 due to negative pressure, the shape of the flange part 24 is made to be approximately similar to the film part 18a of the diaphragm 18, and a curl part 26 is provided on the peripheral edge. The membrane portion 18a does not invert significantly, and the curved surface of the curl portion 26 and the membrane portion 18
Since a contacts the film portion 18a, the film portion 18a is not damaged. Further, since the opposing surfaces of the diaphragm 18 and the flange portion 24 are treated with non-adhesive treatment, the membrane portion 18a does not stick to the flange portion 24.

As detailed above, this embodiment has the following effects.

(1) When the primary pressure chamber 10 becomes negative pressure, the diaphragm 1
The membrane part 18a of 8 is in close contact with the flange part 24 and the effective pressure receiving diameter becomes large, and the valve body 14 is automatically opened to release the negative pressure. Therefore, the flow control valve 2 with a closing function
prevent it from becoming inoperable.

(2) Since the flange portion 24 has a substantially similar shape to the membrane portion 18a, the shape of the membrane portion 18a does not change significantly. Additionally, a curled portion 26 is formed on the periphery of the flange portion 24.
Therefore, the membrane portion 18a is not damaged. Therefore, reliability against damage to the diaphragm 18 is improved.

(3) Since the negative pressure in the primary pressure chamber 10 is automatically released, there is no need to increase the opening force of the shutoff valve 1. Therefore, since the coil 9 can be made smaller, the shutoff valve 1
Achieve smaller size and lower cost.

(4) Since either or both of the facing surfaces of the diaphragm 18 and the flange portion 24 are treated with non-adhesive treatment, the membrane portion 18a does not stick to the flange portion 24.

Effects of the Invention As described above, the flow rate control device according to the present invention includes a shutoff valve and a flow control valve with a shutoff function provided downstream of the shutoff valve, and the fluid pressure acting side of the diaphragm provided in the flow control valve with a shutoff function. A membrane plate having a flange portion with a pressure-receiving diameter larger than the effective pressure-receiving diameter of the diaphragm is provided integrally with the valve body to automatically open the valve body when the pressure on the fluid pressure acting side of the diaphragm becomes negative pressure. The valve is designed to release negative pressure, and its simple configuration does not affect the flow rate control performance during steady state, and the flow rate does not cause the inability to open the valve, which occurs when the fluid pressure acting side of the diaphragm becomes negative pressure. A control device can be realized. If a flow control valve with this type of closing function is left closed for a long period of time, the elastic body provided at the contact area between the valve body and valve seat may stick to the valve seat or the valve body, making it impossible to open the valve. However, in the present invention, since the valve is automatically opened when the negative pressure is released, there is an effect of preventing sticking.

Further, since the membrane portion of the diaphragm is received by the flange portion of the membrane plate, the membrane portion is not reversed. Furthermore, when the negative pressure is released, the deformation time can be shortened because it returns to its normal state. Therefore, the durability and reliability of the diaphragm are improved. Furthermore, since the negative pressure is automatically released, a large negative pressure does not act on the valve body of the shutoff valve, so there is no need to increase the valve opening force. Therefore, the shutoff valve can be made smaller and lower in cost.

In addition, in this type of flow control valve with a closing function, if left in the closed state for a long period of time, the elastic body provided on the valve body and the valve seat may stick together, making it impossible to open the valve, but with the present invention, negative pressure can be removed. When releasing the valve, the valve body is forcibly pushed down to open the valve, which also has the effect of preventing the valve from sticking.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional structural diagram of a conventional flow control device, Fig. 2 is an enlarged cross-sectional view of the same main part, Fig. 3 is a cross-sectional structural diagram of a flow control device showing an embodiment of the present invention, and Fig. 4 is the same. FIG. 2 is an enlarged cross-sectional view of the main part of the device. 1... Closing valve, 2... Flow control valve with closing function,
4...Fluid passage, 12...Valve seat, 14...Valve body,
15...Elastic body, 16...Elastic member (biasing element),
17, 25... Membrane plate, 18... Diaphragm, 1
8a... Membrane part, 19... Atmospheric pressure chamber, 22... Drive part, 24... Flange part, 26... Curl part.

Claims (1)

[Claims] 1. A shutoff valve that shuts off a fluid passage, and a flow control valve with a shutoff function that is installed downstream of the shutoff valve and has a function of shutting off the fluid passage, and the flow control valve is installed in the fluid passage. a valve seat, a valve body provided opposite to the valve seat, an elastic body provided at a contact portion between the valve seat and the valve body, and a biasing element that biases the valve body to close; A diaphragm that is provided integrally with the valve body and has an effective pressure receiving diameter substantially equal to that of the valve body, a membrane plate provided on the atmospheric pressure chamber side of the diaphragm, and the shutoff valve, the diaphragm, and the valve body. A flow rate control device comprising: a membrane plate provided on the side of a closed space, and having a flange portion having a pressure receiving diameter larger than an effective pressure receiving diameter of the diaphragm; and a drive section for operating the valve body. 2. The flow control device according to claim 1, wherein the flange portion of the membrane plate has a similar shape to the diaphragm membrane portion, and a curl portion is provided at the periphery of the flange portion.