JPS6127763B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a constant flow valve for controlling a constant flow rate.

Conventionally, there are the following types of metering valves for controlling the flow rate at a constant level.These valves are made by sliding a thin plate-like piston with a liquid passage hole into a flow path formed in the valve body. A needle is movably inserted and fixedly provided facing the liquid passage hole on the downstream side of the piston, and a flow rate control spring is further provided that biases the piston in a direction away from the needle, that is, toward the upstream side. The structure is as follows. Then, the piston comes to rest at a position where the differential pressure acting on its upstream side and downstream side balances the biasing force of the flow rate control spring, and the opening of the liquid passage hole at this time, that is, the needle A constant flow rate is controlled in accordance with the aperture opening area determined by the distance between the opening edge of the liquid passage hole and the opening edge of the liquid passage hole, and flows downstream of the piston.

However, in such conventional constant flow valves, the piston has a primary fluid pressure that acts on its upstream surface, and a secondary fluid pressure that is controlled to a constant flow that acts on its downstream surface. Due to the large pressure difference between the fluid pressure on the next side and the fluid pressure on the next side, the following problems occurred. That is, in order to counter the above-mentioned large differential pressure, the flow rate control spring needs to have a large biasing force, so the flow rate control spring becomes large.
Further, the work of assembling the flow rate control spring, which has a large biasing force, was difficult. Furthermore, since the flow rate must be controlled to a constant level simply by passing the piston, variations in the finishing accuracy of the piston and needle and variations in the mounting position immediately affect the flow rate control accuracy.

The present invention solves the above-mentioned problems, and provides a constant flow valve that generates a small pressure difference depending on the fluid pressure on the primary side and uses this small pressure difference to control the flow rate to a constant flow rate. The purpose is to provide

The invention will be explained below with reference to illustrated embodiments. In FIG. 1, a valve body 1 is composed of a cylindrical body 2 and plate members 3 and 4 welded to both ends of the cylindrical body 2, respectively, and holes are opened in each of the plate members 3 and 4. As a result, a flow path 7 is formed in the valve body 1, with the hole in the plate member 3 serving as an inlet 5 and the hole in the plate member 4 serving as an outlet 6. The hole in the plate member 3 that becomes the inlet 5 is formed in an annular shape with a smaller diameter than the inner diameter of the cylinder 2 (see FIG. 3), and the outlet 6
As shown in FIG. 4, the hole in the plate member 4 is shaped such that the support portion 4a crosses the center of the annular hole, and the cylinder 2 and the plate members 3, 4 are connected to each other. As described above, they are integrated so that their inner diameter centers lie on the same straight line.

A multistage guide rod 8 extending in the fluid flow direction is disposed in the flow path 7. The right end of the guide rod 8 is fixedly held on the support portion 4a of the plate member 4, and the left end is fixed to the support portion 4a of the plate member 4. It extends to Entrance 5.

Reference numeral 9 denotes a valve body which is slidably fitted into the guide rod 8 and is movable in the direction of the flow path 7 using the guide rod 8 as a guide.The valve body 9 has a shape as shown in FIG. It is configured. That is, the valve body 9 has a cylindrical sliding part 9a that is a sliding part with respect to the guide rod 8, and extends in a direction perpendicular to the longitudinal direction of the sliding part 9a at the left end of the sliding part 9a in FIG. A narrow plate-shaped pressure receiving part 9b that penetrates through the pressure receiving part 9b, a cylindrical cylindrical part 9c facing the opening edge of the outflow port 6 at a position remote from the pressure receiving part 9b on the downstream side, and the cylindrical part 9c and the pressure receiving part 9b. It is composed of a pair of connecting portions 9d, 9d connecting the two. And in the sliding part 9a,
An orifice 9e is formed to communicate the chamber 17 formed between this and the guide rod 8 with the flow path 2, and the width of the pressure receiving part 9b is formed larger than the outer diameter of the sliding part 9a, and the width of the pressure receiving part 9b is formed to be larger than the outer diameter of the sliding part 9a. The cylindrical portion 9c is formed in an arc shape so as to slide on the inner wall surface of the plate member 3, and the inner diameter of the cylindrical portion 9c is approximately the same as the diameter of the outlet 6. Note that the cylindrical portion 9c and the connecting portions 9d, 9d are as follows:
It is formed by cutting out a part of a cylinder with a length including both parts 9c and 9d, 9d.

Further, an annular spring receiver 10 is welded to the guide rod 8 and is fitted in a predetermined position using the stepped portion, and is stretched between the spring receiver 10 and the pressure receiving portion 9b of the valve body 9. The valve body 9 is controlled by the flow rate control spring 11.
is energized toward the inlet 5 side, and leftward movement of the valve body 9 beyond a predetermined amount is restricted by the pressure receiving portion 9b coming into contact with a retaining ring 12 attached to the left end of the guide rod 8. There is. The outer diameter of this spring receiver 10 is the same as the inner diameter of the cylindrical portion 9c of the valve body 9, and
The spring receiver 10 is always located within the cylindrical portion 9c regardless of the movement of the valve body 9, so that the spring receiver 10 and the cylindrical portion 9c slide.
serves as a member to prevent fluid from flowing through the cylindrical portion 9c.

The constant flow valve configured as described above is sandwiched, for example, between the flanges 13a and 14a of the pipes 13 and 14, and the flanges 13a and 14a are tightened using bolts 15 and nuts 16 and 16. connected by Now, when the primary fluid whose flow rate is to be controlled flows into the inlet 5 from the piping 13, a force that moves the valve body 9 to the right in accordance with the flow velocity at this time acts on the upstream side surface of the pressure receiving part 9a. It acts in accordance with the magnitude of the small pressure difference ΔP between the pressure P ₁ acting on the downstream surface and the pressure P ₂ acting on the downstream surface. Due to this differential pressure ΔP, the valve body 9 is activated by the flow rate control spring 11.
The valve body 9 moves to the right while compressing the pressure, and the valve body 9 comes to rest at a position where the force due to this differential pressure ΔP and the biasing force of the flow rate control spring 11 are balanced. At this time, the cylindrical portion 9c
The fluid on the secondary side, which is controlled at a constant flow rate, flows from the outlet 6 to the pipe 1 according to the aperture opening area determined by the distance l between the right end of the outlet 6 and the opening edge of the outlet 6.
It will flow to 4.

As the flow rate from the pipe 13 increases, the flow velocity of the fluid on the primary side also increases, and therefore the differential pressure ΔP also increases, and the valve body 9 comes to rest at a position further moved to the right. At this time, as the flow velocity increases, the aperture opening area also decreases, so the flow rate of the fluid on the secondary side flowing from the outlet 6 becomes the same constant flow rate as in the above case. Of course, in order to make the flow rate of the secondary side fluid flowing out from the outlet 6 constant and predetermined, the pressure receiving area of the pressure receiving part 9a and the flow rate control spring force are adjusted so that the throttle opening area corresponds to the flow velocity. etc. are determined in advance to be appropriate.

Conversely, when the flow rate from the inlet 5 decreases, the differential pressure △P also decreases, and the valve body 9 moves to the left and then comes to rest, increasing the aperture opening area, and the flow rate from the outlet 6 increases as in the case described above. Similarly, it is controlled to a predetermined constant.

Here, if the fluid pressure on the primary side suddenly increases for some reason and the valve body 9 tries to move rapidly to the right, the volume of the chamber 17 rapidly decreases and the fluid inside passes through the orifice 9e. When this happens, a large resistance force is generated, and this resistance force prevents the valve body 9 from moving rapidly to the right.

In the above embodiments, the case where the valve body 9 has a shape as shown in FIG. 2 has been explained, but the shape is not limited to this. Any structure may be used as long as it has a cylindrical portion that allows the aperture area to be determined without directly receiving differential pressure.

As described above, in the present invention, when the valve body is moved to control the flow rate, the flow rate of the primary side fluid to be controlled is controlled regardless of the fluid pressure on the secondary side after the flow rate has been controlled to a constant level. Since this is done using only a small differential pressure that acts on the pressure receiving part of the valve body, the spring force of the flow rate control spring to bias the valve body against the differential pressure is small. This makes it possible to reduce the size of the valve itself and facilitate the installation work.

In addition, the valve body has a pressure receiving part that receives the differential pressure caused by the fluid pressure on the primary side and a cylindrical part that determines the aperture opening area as mutually independent elements. It can be increased more than that.

Furthermore, since the valve body moves with the guide rod as a sliding guide, its movement is smooth, and since the valve body is not used as a sliding guide for the valve body, there is no need for sophisticated finishing of the inner wall surface of the valve body. Therefore, the valve body can be formed from a plurality of sheet metal members without casting or the like, and can be provided at low cost.

[Brief explanation of the drawing]

Figure 1 is a sectional view along the flow path direction of the constant flow valve according to the present invention, Figure 2 is a perspective view of the valve body, Figure 3 is a view taken in the direction of arrow A in Figure 1, and Figure 4 is in the direction of Figure 1 B. Arrow view. 1... Valve body, 7... Channel, 8... Guide rod, 9...
Valve body, 9b...Pressure receiving part, 9c...Cylinder part, 9e...Orifice, 10...Spring receiver (flow blocking member), 11...Flow rate control spring.

Claims (1)

[Scope of Claims] 1. A guide rod is fixedly disposed in a flow path formed in a valve body, and a valve body is fitted into the guide rod so as to be slidable in the direction of the flow path. A flow rate control spring is provided that biases the valve body in the direction of fluid inflow, and the valve body includes a cylindrical portion that cooperates with the valve body to determine the aperture opening area of the flow path, and a cylindrical portion of the cylindrical portion. a pressure receiving part located on the upstream side and receiving a differential pressure according to the pressure of the primary fluid whose flow rate is to be controlled; A constant flow valve characterized by being provided with a flow blocking member for 2. The flow prevention member is fixed to a guide rod fixedly held on the valve body and is a spring receiver that fits into the cylindrical portion of the valve body, and the spring receiver serves as a seat on one end side of the flow rate control spring. A constant flow valve according to claim 1. 3. The constant flow valve according to claim 1 or 2, wherein an orifice is opened in the sliding portion of the valve body with respect to the guide rod to communicate the inside and outside of the valve body.