JPH0579865B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an air valve installed in a water supply pipe.

[Prior art] Air valves exhaust air from the pipe when water is flowing through the pipe, and supply air into the pipe when draining water from the pipe, pressurizing the inside of the pipe and producing pressurized water. When the pipe is in a flowing state, it is installed for the purpose of discharging air or gas separated from the water from the pipe when the water is full.

Conventionally, many technologies have been disclosed regarding air valves. Figure 4 is established in the Japanese Industrial Standards.
JIS B 2063 single-port air valve for water supply. This is because the lower opening 42 provided at the bottom of the valve box 41 installed at the top of the water pipeline communicates with the inside of the pipe, and the apparent specific gravity of the valve body stored in the valve box 41, which can be raised and lowered, acts as a valve body. A float 43 of 1 or less (0.75 to 0.80) moves up and down in conjunction with fluctuations in the water level inside the valve box 41.
An air hole 46 provided in an elastic valve seat 45 fixed to the center of an upper lid 44 that closes the upper part of the valve is opened and closed.

To explain the function of this air valve in detail, when water is flowing, the air in the pipe is discharged from the air hole 46,
When the inside of the pipe becomes full of water and the water level in the valve box 41 rises, the float 43 also rises and comes into close contact with the valve seat 45 to close the air hole 46. When draining water from the pipe, when the water level in the valve box 41 drops, the float 4
3 also descends away from the valve seat 45 and opens the air hole 46, so that air is supplied into the pipe line from the air hole 46.
In addition, so-called pressure exhaust, in which air and gas separated from water are discharged when the pipe is pressurized and full of water, is performed when the float 43 is in a fully closed state with the valve seat 45 in close contact with the inside of the valve box 41 and the atmosphere. The force to bring the float 43 into close contact with the valve seat 45, which is the product of the pressure difference (hereinafter referred to as the pressure difference between the inside and outside of the valve) and the cross-sectional area of the air hole 46, and the weight of the float 43 cause the float 43 to The forces trying to separate it from the valve seat 45 are opposing each other, and when air or gas separated from the water accumulates in the upper part of the valve box 41 and the water level falls, the buoyant force acting on the float 43 decreases, causing the float 43 to move away from the valve seat 45. When the weight increases, the float 43 moves away from the valve seat 45 and descends, opening the air hole 46 and exhausting the air. When exhaust is performed and the water level rises, the float 43 rises and comes into close contact with the valve seat 45, closing the air hole 46.

[Problems to be Solved by the Invention] As mentioned above, in conventional air valves, the force that tries to bring the float into close contact with the valve seat is equal to the product of the differential pressure inside and outside the valve multiplied by the cross-sectional area of the air hole. Therefore, in order to exhaust air under pressure, there are structural limitations depending on the relative relationship between the differential pressure inside and outside the valve, the cross-sectional area of the air hole, and the weight of the float. In other words, from the above relative relationship, when the differential pressure is large, the air hole will not open and the valve will not operate unless the weight of the float is increased.If the air hole is made larger at the same differential pressure, the weight of the float must be increased. Otherwise, the valve will not operate. Furthermore, if the weight of the float is the same, the air hole must be made smaller when the differential pressure is large. In general, the functions required of an air valve are to be applicable over a wide range of differential pressures inside and outside the valve, and to have the air hole as large as possible in cross-sectional area and the float to be as small as possible. If the float is large, the entire valve box will also be large and heavy, which will be an obstacle when installing it in the pipeline. Furthermore, the smaller the air holes are, the more likely they are to become clogged, which can be fatal in the case of agricultural water or sewage that contains a large amount of solid matter. The conventional technology mentioned above (Figure 4) is a standard type that targets fresh water, and since the contact area between the air hole inlet and the float is close to the water surface, there is no chance that solids will adhere to it together with the water. This tends to cause sewage to spurt out to the top of the valve box along with the exhaust air, and this often clogs the thin air holes and causes the valve to lose its function. Recently, specifications for pumping sewage have been increasing, and it is difficult to use the air valves used in clean water (water supply) pipes as they are, and even if they are used, it is difficult to expect sufficient functionality. be.

In order to solve the above-mentioned problems, the present invention has developed a new air valve that keeps the force required when opening and closing the air hole almost constant regardless of the differential pressure inside and outside the valve or the cross-sectional area of the air hole. For the purpose of providing.

[Means for Solving the Problems] The air valve according to the present invention is supported by a fulcrum 4 erected approximately above the center of a sealing lid 3 of a valve box 1 having a lower opening 2 communicating with the inside of a water supply pipe. A link lever 5 is rotatably hung horizontally, and a weight 11 is suspended from one end of the link lever so as to be able to rise and fall via a valve body 7 that opens and closes an air hole 8 in the valve box. The other end engages with a push rod 10 that is suspended in a vertically movable manner within a through hole of the sealing lid, and within the through hole, the push rod is provided with a spring 13 on its outer periphery that biases it downward, and its lower end Now, diaphragm 1 stretched at the bottom of the through hole.
A diaphragm piston 12 is formed which moves together with the diaphragm piston 5, and the ratio of the distance between the fulcrum 4 and the end point 6 that suspends the valve body and the distance between the fulcrum 4 and the end point 9 that suspends the push rod is determined by the pressure received by the diaphragm piston. area and
The above problem was solved by setting the ratio to be approximately equal to the cross-sectional area ratio of the air holes.

[Operation] Figures 1 to 3 show examples of the operation of the present invention.
This will be explained based on the diagram.

A fulcrum 4 is erected approximately above the center of the sealing lid 3 of the valve box 1 connected to the water supply pipe A through the lower opening 2,
A link lever 5 that engages with this fulcrum is placed horizontally on the sealing lid. A valve body 7 is suspended from one end point 6 of this link lever to open and close an air hole 8. A weight 11 is further suspended from the valve body 7 and can be moved up and down as a unit. A push rod 10 is suspended from the other end point 9 of the link lever so as to be able to rise and fall.
It is also surrounded by biasing means 13 mounted on and across from it. That is, the end point 9 of the link lever 5 is configured to have a biasing force that tends to push the push rod downward, and a piston effect that tries to push the push rod upward due to the differential pressure.

Next, calculate the distance L 1 from the fulcrum 4 to one end point 6 (valve body/weight suspension fulcrum), and the distance L ₁ from the fulcrum 4 to the other end point 9.
(The suspension fulcrum of the push rod) is the ratio M of the distance L ₂ to the pressure receiving area S ₁ of the diaphragm piston and the cross-sectional area of the air hole.
Since the ratio of S to _S2 is set approximately equal to N, the force acting on the valve body due to the differential pressure inside and outside the valve is canceled out by the force generated on the diaphragm piston.
The force that tries to move the valve body and close the air hole is only the pressing force from the biasing means that overcomes the gravity of the weight, and it has nothing to do with the size of the differential pressure inside and outside the valve or the size of the cross-sectional area of the air hole. The value remains almost constant.

Therefore, if this pressing force is set between the maximum and minimum weight that the weight changes as the water level rises and falls, the air valve will always be able to operate without being affected by changes in other conditions. Able to function normally. To explain this simply using a mathematical formula, P is the differential pressure between the inside and outside of the valve, W is the difference between the pressing force by the urging means and the power of the weight, and F is the force that tries to close the valve due to the differential pressure P. , if the force that tries to open the valve due to the differential pressure P is G and the weight other than the weight is ignored, then L ₁ /L ₂ =M S ₁ /S ₂ =N F=P×M/N+W G=P× 1 F-G=W, and the force to close the valve is approximately the difference W in the pressing force by the biasing means that overcomes the gravity of the weight, and it does not change as long as the gravity of the weight does not change, and changes in buoyancy due to changes in the water level. It fluctuates only when it receives fluctuations, and the valve opens or closes depending on the force relationship.

[Examples] Preferred embodiments of the present application will be described while avoiding duplication with the previous section.

In the figure, an elastic diaphragm 1 is attached to the lower end of a through hole 14 formed in the sealing lid 3 on one end of the valve box 1.
5 is stretched, and the lower end surface of the push rod 10 and the mounting material 16
A diaphragm piston 12 is formed between the two.

In this example, a compression spring is selected as the biasing means 13, and its biasing force can be adjusted by adjusting the tightening condition of the adjustment member 27 fitted into the mounting lid 25.

The valve body 7 suspended from the end point 6 attaches and detaches to open and close the valve, and the valve seat 18 is the valve seat 18. The valve seat has an air hole 8 in the center and a valve seat surface 1 of the valve body at the bottom.
9 and the valve seat surface 20 of the valve seat 18 are opposed to each other. The valve seat 18 is fixed to the airtight lid 3, and a support member 21 placed on it has a plurality of screw holes 22 that communicate with air holes passing through the peripheral wall, and serves as an air inlet/outlet between the inside and outside of the valve box. is formed. In this example, a float having an apparent specific gravity smaller than that of water is selected as the weight 11, and is suspended downward by a rope 17.

A long hole 23 is provided at one end point 6 of the link lever 5.
In addition, the other end point 9 is provided with a long hole 24, and the valve body 7 and push rod 10 are rotatably connected via pins 28, 29 and connecting members 30, 31. The valve body and push rod are suspended within the valve box so that they can move up and down.

In FIG. 1, water has not yet been sent to the water supply pipe A and there is no water in the valve box, so no buoyancy is acting on the float 11, so its weight acts as a load, and the valve body 7 The valve seat surface 19 overcomes the upward pressing force of the compression spring 13 and the valve seat surface 2
0 and the air hole 8 is fully open.

When water starts flowing in this state and the inside of the pipe becomes filled with water, the air inside the pipe enters into the valve box 1 through the lower opening 2 and the air hole 8 and the screw hole 22, as shown in FIG. After that, it is discharged to the outside. When the pipe becomes full and water enters the valve box and the water level rises, the buoyancy acting on the float increases and the downward force of gravity decreases, so the pressing force of the compression spring decreases. As a result, the valve seat surface 19 and the valve seat surface 20 come into close contact with each other, the air hole 8 is closed, and the valve becomes fully closed.

While the valve remains closed, air and gas mixed in the water separate and accumulate at the top of the valve box, and as the water level drops, the buoyant force acting on the float also decreases, and the weight of the float finally decreases. When the pressing force of the compression spring is exceeded, the valve seat surface 19 is pulled away from the valve seat surface 20 as shown in FIG. Ru. When exhaustion under pressure is finished, the water level in the valve box rises and the air hole closes again, returning to the state shown in FIG. 2.

[Effects of the Invention] Since the present invention produces the effects described above, it brings about the following effects. In other words, the cross-sectional area of the air hole is large over a wide range of differential pressure inside and outside the valve.
The weight allows the specification of small compact air valves. Even if the differential pressure is the same as before, the size of the air hole can be changed significantly without changing the size of the air valve, so it can be used for agricultural water, sewage, etc. that contain countless fine solids. It is suitable as a water pipeline for contaminated water. In addition, the opening and closing of the air hole is not done directly by attaching and detaching it to the float, but is done at the top, far away from the rising and falling water surface, so there is no need to worry about it becoming contaminated by being immersed in sewage, and sewage does not flow outside the valve box. There is no danger that it will blow up.

The unique effect of this embodiment is that since the weight is a float with an apparent specific gravity of 1 or less, the gravity on the valve body is extremely small in the closed state, and the spring constant of the compression spring that balances this is also small. Its length can be shortened. Also,
Since the communication port for air and gas with the outside is formed by the screw hole 22, even if dirt etc. adheres to the vicinity of the tip of the valve body 7 or to the surfaces of both valve seats, the screw at the end of the cleaning water pipe can be inserted into the screw hole. You can easily wash it off by screwing it in and supplying water.

[Brief explanation of the drawing]

1 to 3 are vertical sectional views showing an embodiment of the present invention, and FIG. 4 is a vertical sectional view showing a conventional technique. 1...Valve box, 2...Lower opening, 3...Tight lid,
4...Fully point, 5...Link lever, 6...End point (suspension fulcrum of valve body), 7...Valve body, 8...Air hole, 9
... End point (hanging fulcrum of push rod), 10 ... Push rod,
11... Weight, 12... Diaphragm piston, 1
3...Biasing means, _L1 ...Distance from the fulcrum to the end point 6, _L2 ...Distance from the fulcrum to the end point 9, M=
L ₁ /L ₂ , S ₁ ...Pressure receiving area of diaphragm piston, S ₂ ...Cross-sectional area of air hole, S ₁ /S ₂ =N.

Claims (1)

[Claims] 1. A link lever 5 supported by a fulcrum 4 erected approximately at the center of a sealing lid 3 of a valve box 1 having a lower opening 2 communicating with the inside of a water supply pipe is horizontally mounted so as to be freely rotatable.
A weight 11 is suspended from one end of the link lever so that it can be raised and lowered via a valve body 7 that opens and closes an air hole 8 in the valve box, and the other end of the link lever 5 can be raised and lowered within a through hole of the sealing lid. A spring 13 is provided on the outer periphery of the spring 13, which engages with the suspended push rod 10 and urges the push rod downward within the through hole, and its lower end moves in conjunction with a diaphragm 15 stretched over the bottom of the through hole. A diaphragm piston 12 is formed, and the ratio of the distance between the fulcrum 4 and the end point 6 that suspends the valve body, and the distance between the fulcrum 4 and the end point 9 that suspends the push rod is the pressure receiving area of the diaphragm piston and the air An air valve characterized in that the ratio of the cross-sectional area of the hole is set to be approximately equal to the ratio of the cross-sectional area of the hole.