JPS606700Y2 - Reduced pressure flow control valve - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a flow control valve used mainly in high-pressure boilers such as power generation boilers.

It is often necessary to depressurize and remove small amounts of liquid from high pressure boilers.

For example, in a high-pressure boiler for power generation, in order to preserve the can body, a small amount of can water is sampled at appropriate times (usually once a day), and the components are analyzed using it as a sample. Water quality is controlled by injecting a can cleaning agent.

In this case, a pressure reduction flow control valve must be connected to the boiler can body, and the valve must be opened to reduce the pressure of the high-pressure can water to atmospheric pressure, and to take out the required small amount of sample.

By the way, in boilers for power generation, etc., the internal pressure of the can is approximately 150 kg/al! Since the pressure is extremely high, the canned water cannot be safely removed unless the pressure is sufficiently reduced.

Conventional pressure reducing flow control valves used for this type of application include those that utilize the throttling effect of an orifice and those that utilize the frictional resistance of a pipe.

As the former type of valve, a needle valve is mainly used, and a capillary tube in which a core wire is inserted into a thin tube is used as a valve that uses fluid abrasion resistance of the tube.

Needle valves rapidly reduce high pressure at the surface that touches the valve seat, which can cause decomposition of canned water and change the quality of the water, making it unsuitable for use as a sample.Also, it is difficult to finely adjust the flow rate; Due to this, erosion occurs and the contact surface of the valve is severely damaged, resulting in an extremely short service life.

On the other hand, in capillary tubes, in order to obtain the required pressure reduction performance, the gap between the outer tube and the core wire must be kept small and the length must be sufficiently long (for example, about 1 m), so it is easy for clogs to occur due to scale and dust inside the tube. Another drawback is that the distance between the core wire and the wire is long, making it impossible to adjust the flow rate.

Conventionally, therefore, a needle valve is connected to the outlet of the capillary tube, and after the pressure is previously reduced by the capillary tube, the pressure is further reduced by the needle valve to adjust the flow rate.

For this reason, this pressure reducing device is complicated, and maintenance is also complicated.

A throttle valve that replaces a needle valve and can be used as a pressure reducing flow control valve is shown in FIG.

This valve has a valve seat 42 having a relatively elongated cylindrical hole 41, and a piston-like spindle 43 having an outer diameter that is a certain amount smaller than the inner diameter of the valve seat 42 is inserted into the valve seat 42. Therefore, an annular fluid passage 44 (hereinafter referred to as a C passage) having a constant cross-sectional area between the inner diameter of the valve seat and the outer diameter of the spindle.

), and the insertion length of the spindle 43 into the valve seat 42 is changed by moving the spindle in its axial direction, that is, the length of the C passage is changed to adjust the restriction. It is.

When this type of throttle valve is used for high-pressure fluid, in order to achieve high pressure reduction performance, it is necessary to make the cross-sectional area of the C passage small, so that the gap is very small. , requires great precision in manufacturing, and since the gap is small, clogging is likely to occur even on a very small scale.

A valve constriction that overcomes this drawback is shown in FIG.

This valve has several or a large number of mutually independent annular grooves 22 carved along the outer periphery of the outer surface of the spindle 21, and these annular grooves 22 aim to increase the pressure reduction effect. .

However, by carving the annular groove 22, C
The cross-sectional area of the passage cannot be made very wide, and in this case, the pressure is mainly reduced in the narrow gap between the spindle 21 and the valve seat 23, so the upper end surface of the valve seat 23 is located on the annular groove 22 on the spindle 21. There is a drawback that the reduced pressure flow characteristics change abruptly in stages near this state.

Furthermore, a fluid expansion valve is known in which circumferential grooves with large openings are carved at regular intervals on the outer peripheral surface of the spindle, and horizontal recesses are formed in the valve seat at the same pitch as the circumferential grooves. .

(Japanese Unexamined Patent Publication No. 47-2480) However, according to this structure, it is necessary to accurately match the pitch between the circumferential groove on the outer circumference of the spindle and the recess on the inner surface of the valve seat, so high processing accuracy is required. In addition, the fluid passage formed by the circumferential groove and the recess does not change direction midway, so there is a drawback that reduced pressure flow control cannot be expected by rapid direction change of the fluid.

Additionally, an improved version of the throttle valve used in the reduced pressure flow control valve is shown in FIG.

In this valve, the annular passage 33 formed by the inner diameter of the valve seat 31 and the outer diameter of the spindle 32 is almost zero, and a continuous spiral groove 34 is carved on the outer surface of the spindle 32. .

The fluid passage of this valve is essentially only the spiral groove 34, and a relatively long passage can be formed, the reduced pressure flow rate characteristics are continuous, and clogging due to scale etc. is less likely to occur.

However, in this case the passage is continuous and there are few changes in the direction of flow, so the resistance of the passage is not very large.

In order to eliminate the drawbacks of these flow rate control valves, the present invention creates a high resistance flow path that combines a restriction, which is a factor of fluid resistance, and a sudden change in the flow direction, and has a structure that allows the flow rate to be adjusted. Therefore, an important object of the present invention is to provide a pressure-reducing flow rate control valve in which the liquid flow path is not easily clogged with scale, and even if it is clogged, it can be easily removed.

Another important object of the present invention is to provide a pressure reducing flow control valve that is durable and has a long service life, and even if the throttle part is damaged, it can be easily restored and maintenance management is simple. It is in.

An embodiment of the present invention will be described below with reference to the drawings.

The pressure reducing flow control valve shown in a vertical cross-sectional view in FIG. The valve stem 7 is equipped with a piston-shaped spindle 4 inserted with almost no clearance.

As shown in detailed views of FIG. 5, FIG. 7, and FIG. 8, the spindle 4 has a plurality of annular grooves 51 carved independently from each other along its outer periphery. , these mutually adjacent grooves 51 are communicated by grooves 52 carved on the outer periphery in a direction parallel to the axis of the spindle 4.

As shown in FIG. 5, the grooves 51 extend in a direction perpendicular to the axis of the spindle 4 and are spaced apart from each other by a predetermined distance.

The vertical grooves 52 are arranged so that the fluid that flows into the groove 51 from here does not immediately flow into the vertical groove 52 directly above, that is, the fluid that flows into the groove 51 from the vertical groove 52 flows along the groove 51. As shown in FIGS. 5 and 6, the vertical grooves 52 adjacent to each other are formed so that they swell sufficiently within the grooves 51 and impinge on the side surfaces of the grooves 51 to lose the energy of movement. 51
The vertical grooves 52, which are vertically adjacent to each other and connected to each other, are offset in the length direction of the groove 51, and are provided at symmetrical or almost symmetrical positions with respect to the axis of the spindle in the figure.

Further, as shown in FIG. 1, the spindle 4 makes a helical movement between the valve stem 7 to which it is attached and the internal thread 9 by means of a helical screw 8 carved in its upper part, and the handle wheel 10 rotates. As a result, the spindle 4 is movable in the axial direction.

A fluid passage is formed by the groove 51 and the vertical groove 52 between the spindle 4 and the valve seat 3 thus formed.

If this passage is expanded and drawn in a planar shape for easy understanding, it will have the shape shown in Fig. 6.

Hereinafter, the vertical groove 51 and the horizontal groove 52 will be collectively referred to as the Z passage 61.
It is called.

A pressure reducing flow control valve having a fluid passage of this shape repeats throttling, changes in the perpendicular flow direction, rapid expansion/contraction of the passage, and changes in branching/merging while fluid flows through the Z passage 61. .

Therefore, this shape of the pressure reducing flow control valve has the advantage of being able to most effectively reduce the pressure of the fluid and adjust the flow rate.

The flow rate is adjusted by this pressure reducing flow control valve on the spindle 4.
This can be done by changing the length of the two passages 61 by changing the fitting length between the valve seat 3 and the valve seat 3.

This can be easily done by rotating the handle wheel 10 attached to the valve stem 7 to which the spindle 4 is connected, and moving the spindle 4 in its axial direction by the helical movement of the helical screw 8 and female screw 9. can be done.

That is, in FIG. 1, as the handle wheel 10 is rotated and the spindle 4 is raised, the amount of fluid flowing out to the fluid outlet 2 increases, and conversely, when the spindle 4 is lowered, the amount of fluid flowing out to the valve seat 3 increases. The flow rate decreases as the tube is inserted deeper into the tube.

The reduced pressure flow control valve shown in FIG.
The flow rate is zero, that is, it is closed.

In this case, before the valve is completely closed, the tapered enlarged part of the spindle, which is the final stage of closing, and the valve seat surface that is in close contact with it are under low pressure, so erosion at the valve seat area is effectively prevented. , durability is significantly improved.

In addition, in this pressure reducing flow rate control valve, when the flow rate of the fluid is relatively large or when the fluid is a gas such as steam, the '/s groove is inserted between adjacent circumferential grooves in the axial direction of the spindle (not shown). Two or several vertical grooves are carved in parallel and adjacent to each other and spaced apart in the axial direction of the spindle, that is, vertically adjacent vertical grooves in FIG. 1 are offset from the extending direction of the vertical grooves. It is also possible to configure

In the pressure reducing flow control valve shown in FIG. 1, fluid flows in from below and flows upward, but it goes without saying that this valve can also be used in the opposite direction.

Further, although the valve seat 3 is formed into a cylindrical shape and is attached to the valve box 5, it is also possible to form the valve seat 3 and the valve box 5 into an integral structure.

Similarly, the valve stem 7 and the spindle 4 can also be made into an integral structure.

The pressure reducing flow control valve of the present invention has a valve seat with a relatively elongated cylindrical hole, and a rod-shaped spindle having an outer diameter with almost no clearance between the inner diameter of the valve seat and the inner diameter of the valve seat can be moved in the axial direction of the valve seat. Furthermore, a plurality of grooves are cut into the inner surface of the valve seat or the outer surface of the spindle, extending in the circumferential direction, and these plurality of grooves are inserted in the axial direction of the spindle. Furthermore, these grooves are connected to longitudinal grooves, and furthermore, the longitudinal grooves connected to both sides of the groove in FIG. Since the grooves and the longitudinal grooves are connected in an offset manner and are configured to form a fluid passage between the valve seat and the spindle, the fluid flowing into the fluid inlet of the pressure reducing flow control valve is When flowing from the vertical groove to the groove, and every time it flows from the groove to the vertical groove, it collides with the inner surface of the groove and vertical groove, loses kinetic energy, and is depressurized by a sudden change of direction, and gradually gradually The pressure is reduced.

Therefore, the minimum dimension of the fluid passage can be larger than that of a capillary tube or needle valve, so even if scale etc. becomes clogged, the spindle can be pulled out from the valve seat and the clogged area can be removed. By moving it until it comes out of the fit with the valve seat, flushing with fluid can be performed, which can eliminate clogging, providing ease of maintenance that capillary tubes do not have.

Furthermore, even if the fluid passage becomes worn out due to long-term use, if a groove is carved in the spindle with enough allowance in advance, the pressure reduction performance can be improved by increasing the length of the fit between the spindle and the valve seat. It can be restored and its lifespan is significantly longer than that of a needle valve.

Furthermore, as shown in FIG. 2, the reduced pressure flow rate control valve of this invention can adjust the reduced pressure flow rate in a more continuous manner than a valve in which only the circumferential groove 22 is formed.

This is because the pressure reducing flow control valve shown in FIG. The reduced pressure flow rate characteristics change rapidly when it reaches the upper end surface, but the reduced pressure flow control valve of this invention changes the direction of the fluid between the vertical grooves and at this time, the fluid collides violently with the vertical grooves or the horizontal grooves. In order to reduce the pressure, the cross-sectional area of the vertical groove is made larger than the vertical cross-sectional area of the gap in the pressure-reducing flow control valve shown in FIG. 4, thereby achieving sufficient pressure-reducing characteristics.

Therefore, the pressure reduction characteristics are not determined simply by the length of the vertical groove located between the valve seat and the spindle, and it is also possible to realize the feature of being able to control the pressure reduction flow rate in a relatively continuous state.

Furthermore, the pressure-reducing flow rate control valve of this invention can be achieved by a very simple method of carving a plurality of grooves and a vertical groove connecting these grooves on either or both of the inner surface of the valve seat and the outer surface of the spindle. It has the advantage of being easy to process and mass-produced at low cost.

The reduced pressure flow rate control valve shown in Fig. 1 has vertical grooves formed on the surface of the spindle, and these grooves and vertical grooves are carved on the inner surface of the valve seat to create a connection between the valve seat and the spindle. In between, it is also possible to form a fluid passage in the schematic form of the fluid passage shown in FIG.

As described above, the pressure reducing flow control valve of the present invention combines the ease of operation of a needle valve with the gentle pressure reducing characteristics of a capillary tube, and also has the advantage of being resistant to clogging caused by scale, etc. It is also an innovative pressure reduction flow control valve that can maintain long-term pressure reduction performance.

[Brief explanation of the drawing]

Figure 1 is a vertical sectional view of the pressure reducing flow control valve, Figures 2 to 4
The figure is a partial vertical cross-sectional view of the spindle and valve seat, Figure 5 is an external view of the spindle and a cross-sectional view of a part thereof, Figure 6 is a developed view of the grooves on the spindle surface, and Figures 7 and 8 are the ■ of the diagram
They are a cross-sectional view taken along the line -■ and a cross-sectional view taken along the line ■-■. 1...Fluid inlet, 2...Fluid outlet, 3
... Valve seat, 4 ... Spindle, 5 ...
... Valve box, 6... Cylindrical hole, 7...
...Valve stem, 8...Spiral waist 9...
Female thread, 10... Handle wheel, 21...
・Spindle, 22... Annular groove, 23...
... Valve seat, 31 ... Valve seat, 32 ... Spindle, 33 ... Annular passage, 34 ...
・Spiral groove, 41... Cylindrical hole, 42...
...Valve seat, 43...Spindle, 44...
-Fluid passage, 51...Groove, 52...Vertical groove, 61...2 passages.

Claims (3)

[Scope of utility model registration request] (1) In a pressure reducing flow control valve having a fluid inlet and a fluid outlet, a valve seat 3 having a relatively elongated cylindrical hole is provided in a portion that becomes a fluid passage, and there is almost no clearance between the valve seat 3 and the inner diameter of the valve seat 3. A rod-shaped spindle 4 with a flat outer diameter is inserted so as to be movable in the axial direction of the valve seat, and a plurality of rod-shaped spindles are provided on the inner surface of the valve seat 3 or the outer surface of the spindle 4 and extend in the circumferential direction. A plurality of grooves 51 are carved, and these grooves 51 are carved spaced apart from each other in the axial direction of the spindle 4, and furthermore, these grooves 51 are formed in longitudinal grooves 52.
Further, the vertical grooves 52 adjacent to each other on both sides of the groove 51 are connected with their positions shifted in the length direction of the groove 51, and the groove 51 and the vertical groove 52 are connected to each other in the above-mentioned manner. A fluid passage is formed between the valve seat 3 and the spindle 4, and the fluid flowing through this passage is depressurized by changing the flow direction and repeating branching and merging. Reduced pressure flow control valve. (2) The pressure reducing flow control valve according to claim (1), in which adjacent grooves 51 are connected by a single vertical groove 52. (3) The pressure reducing flow control valve according to claim (1), in which adjacent grooves 51 are connected to a plurality of longitudinal grooves 52.