JPH04236861A - Regulating valve - Google Patents

Abstract

PURPOSE:To provide a regulating valve which improves a closing function for a long period and performs control of a flow rate throughout a wide range. CONSTITUTION:A partition wall 4 is located in a valve body 1 to partition inlet and outlet flow passages 2 and 3 from each other, and an opening part 5 through which the inlet and outlet flow passages 2 and 3 are communicated with each other is formed in the partition wall 4. A shut-off valve 10 is disposed facing the opening part 5, and the opening part 5 is spread in a curved state toward the shut-off valve 10 side. A control valve 12 positioned on the spread side of the opening part 5 and disposed coaxially with the opening part 5 and having a flange part 12a by which the inner peripheral surface of the opening part 5 and an orifice 14 are formed is protruded from the lower end of the shut-off valve 10. The shut-off valve 10 is vertically movable and a lower end surface 11 thereof is brought into contact with a valve seat part 15 formed around the opening part 5.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control valve used in fluid transport piping where flow rate adjustment is required.

0002

2. Description of the Related Art In a conventional control valve as shown in FIG. 6, which is equipped with a valve plug and a valve seat, when controlling the flow rate of fluid in a low opening region, that is, near the lower limit of the rangeability of the valve, Due to fluid cavitation caused by fluctuations in pressure conditions before and after the valve, the valve plug and valve seat are locally eroded, and this erosion increases the amount of fluid leakage when the valve is closed, making highly accurate control difficult and causing short-term damage. There was a problem that it became unusable after a while.

[0003]Therefore, various proposals have been made for the purpose of preventing fluid leakage when the valve is closed due to the occurrence of cavitation, and one example of these is disclosed in Japanese Patent Laid-Open No. 59-34073. There is. The control valve disclosed in the publication includes a small diameter portion adjacent to the valve seat, a vertical wall portion larger than the small diameter portion, and an enlarged diameter portion formed in a trumpet shape in which the hole wall expands toward the downstream side. By installing a valve plug with two large and small bodies so that it can move up and down in the inner hole, it prevents erosion of the valve plug and valve seat due to cavitation, and prevents fluid leakage when the valve is closed. The structure is such that the flow rate is controlled by the operation of the valve plug on the circumferential surface of the large body or the smallest opening formed by the seating part and the inner hole.

0004

[Problem to be Solved by the Invention] However, in such conventional control valves, in order to completely close the valve, it is necessary to rub the seating part and the valve seat part together by lapping to make the contact surfaces familiar. Therefore, not only is the machining troublesome and requires high precision, but also the contact surface is worn out due to repeated opening and closing operations of the valve, making it impossible to close the valve.

[0005]Furthermore, the flow rate characteristics of the control valve are obtained by changing the area of the minimum opening formed by the inner hole and the valve plug, but the valve plug is cylindrical and the viscosity of the fluid is Because of its shape, which is susceptible to resistance, it is difficult to obtain the flow characteristics as designed, making it difficult to increase rangeability. The present invention was made in view of the above-mentioned problems, and its purpose is to improve the closing function of the control valve over a long period of time and to provide a control valve that can control the flow rate over a wide range. be.

[0006]

[Means for Solving the Problems] The structure of the present invention for solving the above problems will be explained with reference to FIG. 1, which corresponds to an embodiment of the present invention. The control valve of the present invention includes a partition wall 4 provided between the inlet flow path 2 and the outlet flow path 3 inside the valve body 1 to curve the flow direction, and a partition wall 4 provided in the partition wall 4 between the inlet flow path 2 and the outlet flow path. an opening 5 that communicates with the flow path 3;
and a shutoff valve 10 disposed opposite to the shutoff valve 10, the opening 5 having a curved diameter enlarged toward the shutoff valve 10 side,
At the lower end of the shutoff valve 10, there is a flange located on the enlarged diameter side of the opening 5, disposed coaxially with the axis of the opening 5, and forming an orifice 14 with the inner circumferential surface of the opening 5. Part 12
A control valve 12 having a diameter of
is characterized in that it can move up and down, and its lower end surface 11 can come into contact with a valve seat 15 formed around the opening 5.

According to a preferred embodiment of the present invention, the control valve 12 is composed of a body portion 12b and a flange portion 12a provided at the tip thereof, as shown in FIG. The shape is a combination of a square and a trapezoid, and the diameter of the body: D1 The maximum diameter of the collar
:D2 Thickness of the maximum diameter part of the flange part: t When the angle of inclination connecting the maximum diameter part of the flange part and the body part is θ, 0.1≦D1 /D2 ≦0.7 0<t/D2 ≦0.15 0 They are formed so that the relationship: °≦θ≦45° holds true at the same time.

[0008] By forming the control valve so as to simultaneously satisfy these relationships, pre-designed flow characteristics can be obtained with high accuracy. On the other hand, if the flow rate is outside the above range, it becomes difficult to obtain the flow rate characteristics with high accuracy. The material of the control valve of the present invention may be plastic or metal, and is not particularly limited. Furthermore, the directionality of fluid inflow and outflow is not limited either, and fluid can be caused to flow in from either side of the control valve, and there is no difference in the control function.

[0009]

[Operation] In the present invention having the above-described structure, the fluid flowing in via the inlet flow path 2 passes through the orifice 14 formed by the opening 5 and the flange 12a of the control valve 12, and passes through the outlet flow path 2. flows out to. When the shutoff valve 10 is moved in the direction of the opening 5, the control valve 12 also moves accordingly,
As a result, the area of the orifice 14 formed between the flange 12a and the inner circumferential surface of the opening 5 becomes smaller, so the flow rate of the fluid decreases. Conversely, if the shutoff valve 10 is moved in a direction away from the opening 5, the area of the orifice 14 will be expanded and the flow rate of the fluid will be increased.

Since the flow rate of the fluid is adjusted in this manner, by changing the shape of the inner circumferential surface of the opening 5, a pre-designed valve-specific flow rate characteristic can be easily obtained. Further, if the shutoff valve 10 continues to move toward the opening 5, it will be in a state immediately before closing, but at this time, the pressure on the upstream side of the control valve 12 will first be applied to the space between the control valve 12 and the shutoff valve 10. , and then from the pressure in this space to the pressure in the outlet channel 3, the pressure in the inlet channel 2 gradually drops to the pressure in the outlet channel 3 in two stages. Therefore, the occurrence of cavitation is suppressed.

When the shutoff valve 10 continues to be moved in the direction of the opening 5, the lower end surface 11 of the shutoff valve 10 finally moves toward the opening 5.
The valve seat 15 comes into contact with and is pressed around the valve seat 15, thereby completely closing the space between the inlet flow path 2 and the outlet flow path 3 and stopping the flow of fluid.

0012

Embodiments Examples of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view showing one embodiment of the present invention. In the same figure, 1 is a valve body, and a partition wall 4 is provided inside the valve body to partition an inlet flow path 2 and an outlet flow path 3. A curved flow path is formed between the flow paths 2 and 3. Further, a valve chamber 8 is formed inside the valve body 1 in a direction perpendicular to the axis of the inlet passage 2 and the outlet passage 3.
A shutoff valve 10 is disposed inside.

The partition wall 4 is provided with an opening 5 that communicates the inlet flow path 2 and the outlet flow path 3, and this opening 5 is formed by penetrating a contracting flow pipe 13 that is screwed and bonded to the partition wall 4. It is something that Further, the inner circumferential surface of the opening 5 is curved and expanded in diameter toward the shutoff valve 10 side. The flow contracting tube 13 has a valve seat portion 1 made of an elastic body for sealing that is fitted and bonded to the upper outer circumferential surface of the flow contraction tube 13.
5, and is screwed and bonded to the partition wall 4 so as to sandwich the valve seat portion 15 so as to communicate the inlet flow path 2 and the outlet flow path 3. In this embodiment, the opening 5 is provided by screwing and bonding the flow contraction pipe 13 into the valve body 1.
It may also be provided by opening directly in the partition wall 4.

The shutoff valve 10 is integrally provided at the lower end of a valve shaft 9 held by a lid 7 fixed to the upper part of the valve body 1, and its axis is aligned with the axis of the opening 5. A valve chamber 8 formed by a neck portion 6 located at the upper part of the valve body 1
It is held so that it can move forward and backward within the space. An annular seat 11 is formed around the lower end of the shutoff valve 10 and is capable of coming into contact with the valve seat 15 .

Reference numeral 12 denotes a control valve, which is screwed and adhesively bonded to the lower end of the shutoff valve 10 so that its axis coincides with the axis of the opening 5, and there is a gap between the axis and the inner peripheral surface of the opening 5. It has a flange portion 12a that forms an orifice 14. The shape of the flange of the control valve in this example is D1 /D2 =0.7, t/D2
=0.07, and θ=45°. (See FIG. 4) Note that the control valve 12 may be integrally provided at the lower end of the shutoff valve 10. Further, the shape of the flange portion 12a is not limited to this embodiment, and may be a disk shape or an inverted truncated cone shape. The shape of this embodiment is an example of a suitable shape.

The operation of the control valve of this embodiment having the above structure is as follows. In FIG. 1, the fluid that has flowed in via the inlet flow path 2 flows through the opening 5 and the flange 1 of the control valve 12.
2a through the orifice 14 formed by the outlet flow path 3.
flows out to. Here, the shutoff valve 10 is connected via the valve shaft 9 by actuation of the drive unit by an automatic control device or by manual operation.
When the control valve 12 is moved toward the opening 5, the control valve 12 also moves accordingly. Accordingly, the area of the orifice 14 formed between the flange 12a of the control valve 12 and the inner circumferential surface of the opening 5 becomes smaller, so the flow rate of the fluid decreases. Conversely, when the shutoff valve 10 is moved in a direction away from the opening 5, the area of the orifice 14 is expanded due to the opposite effect to the above, so that the flow rate of the fluid increases.

The flow rate of the fluid is adjusted by such an action, so that by changing the shape of the inner circumferential surface of the opening 5, a pre-designed valve-specific flow rate characteristic can be easily obtained. Further, when the fluid passes through the orifice 14 in an arbitrary opening state as shown in FIG. 1, the opening state is 0.
1≦D1 /D2 ≦0.7, 0<t/D2 ≦0.1
By forming the control valve 12 so that the relationship of 5,0°≦θ≦45° is established at the same time, the flange 1 is
2a causes sharp separation of fluid streamlines, so resistance due to fluid viscosity is removed, and only pressure resistance mainly acts on the front and rear of the flange 12a.

Therefore, since the flow rate coefficient is stable from low flow velocity to high flow velocity, the relationship between the flow rate of the fluid passing through the orifice 14 and the opening area of the orifice 14 is approximately expressed by a known theoretical formula.

[0019]

[Math 1]

(Q: flow rate, α: flow coefficient, A: orifice opening area, H: differential pressure before and after the orifice). Therefore, the valve-specific flow characteristics designed in advance can be obtained with extremely high accuracy, and the flow rate can be controlled over a wide range from minute flow rates to large flow rates. On the other hand, if the shutoff valve 10 continues to be moved in the direction of the opening 5 from the state shown in FIG. 1, it will be in a state immediately before closing as shown in FIG.

In this state, the pressure on the upstream side of the control valve 12 is P1, the pressure in the space formed between the control valve 12 and the shutoff valve 10 is P2, and the pressure in the outlet passage 3 is P3.
shall be. Between these P1, P2 and P3, P1
>P2, P2 >P3 relationships occur. P1-P
2 = ΔP1, P2 - P3 = ΔP2 and P1
-P3 = ΔP3, then ΔP3 = ΔP1 +Δ
It is clear that P2 holds true.

In other words, the fluid does not undergo a pressure drop of ΔP3 in one step, but gradually causes a pressure drop in two steps, ΔP1 and ΔP2, so that the occurrence of cavitation is suppressed. When the shut-off valve 10 continues to be moved in the direction of the opening 5, the seating portion 11 formed at the lower end of the shut-off valve 10 finally becomes a valve seat portion 15 provided around the opening 5, as shown in FIG. It touches and is pressed. Therefore, the space between the inlet flow path 2 and the outlet flow path 3 is completely closed, so the flow of fluid is stopped and the valve is completely closed.

[0023] Through the above-described actions, the fluid flow rate is adjusted to increase or decrease, and the valve is closed. Here, an actual flow test was conducted under the following conditions using a control valve with a diameter of 15A having the structure shown in FIG. 1, and a control valve in which the shape of the control valve 12 in the control valve was changed in six types. The test was also carried out for conventional products at the same time. [Conditions] Fluid…Water temperature
… 25℃ Pressure difference before and after the valve … 0.7 kgf/c
m2 The results are shown in Table 1 and FIG.

[0024]

[Table 1]

Table 1 shows the maximum error (%) from the design value (corresponding to straight line A2 in FIG. 7) in the above actual flow test results of a control valve with a control valve in which only one requirement (change condition) was changed. ) (corresponding to section A3 in FIG. 7) is shown. As can be seen from Table 1, NO. It can be seen that the control valve No. 4 (product of this example) shows the smallest value of 35%, and the most accurate flow rate characteristics are obtained. Also,
No. Control valves 2, 5, and 8 are the same product, but the maximum error is smaller than the conventional product's maximum error of about 50% (corresponding to section B3 in Figure 7), and this condition is judged to be the upper limit of the product's superiority to the conventional product. .

On the other hand, NO. Control valves 3, 6, and 9 show values close to those of conventional products, and accurate flow characteristics cannot be obtained under these conditions. That is, as shown in FIG.
The shape of the control valve 12 is 0.1≦D1 /D2≦0.7,
It can be seen that if the shape is in the range of 0<t/D2≦0.15 and 0°≦θ≦45°, the accuracy is significantly improved compared to conventional products.

FIG. 7 shows the control valve of this embodiment (the NO
．． 4) and the flow rate characteristics table of the conventional product. As can be seen from the figure, the range ability of the conventional product (curve B1 in the figure) is 2.
Compared to 0:1, the rangeability of the control valve of the present invention (curve A1 in the figure) was significantly improved to 60:1, and it was possible to control over a wide range from minute flow rates to large flow rates. Furthermore, the deviation from the design value (straight line portions A2 and B2 in the figure) was smaller than that of the conventional product, and the flow rate characteristics were obtained with high accuracy.

FIG. 5 is a longitudinal sectional view of a control valve showing another embodiment of the present invention. The control valve of this embodiment has a two-part piece 16a,
It has a diaphragm-type structure, which has a diaphragm 17 sandwiched between the shutoff valve 16 and the shutoff valve 16b, and prevents fluid and foreign matter from entering the sliding portion 18 between the valve body 1 and the shutoff valve 16. The operation and effect are the same as the control valve having the structure shown in FIG.

[0029]

As explained above, since the control valve according to the present invention is constructed as described above, it has the following advantages. - Since the control valve is provided in a shape that is less susceptible to resistance due to the viscosity of the fluid, accurate flow characteristics can be obtained and control can be achieved over a wide range from minute flow rates to large flow rates.

■ Since cavitation can be prevented from occurring in the valve seat and the seating part, the valve seat seating part will not be eroded at all, and leakage of fluid when the valve is closed can be reliably prevented. Its durability can be improved. Furthermore, since cavitation can be prevented from occurring in the control valve and the opening, highly accurate control can be achieved over a long period of time.

[0031] Since there is no need for a troublesome tapered seat or valve seat that requires machining or rubbing, it can be manufactured easily and at low cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing one embodiment of a control valve of the present invention.

FIG. 2 is a vertical cross-sectional view of a main part of the control valve in FIG. 1, showing a state immediately before closing.

FIG. 3 is a longitudinal sectional view showing a closed state of the control valve in FIG. 1;

FIG. 4 is a vertical cross-sectional view of a main part of the control valve in FIG. 1;

FIG. 5 is a longitudinal sectional view of another embodiment of the invention.

FIG. 6 is a longitudinal sectional view of a conventional control valve.

FIG. 7 is a flow rate characteristic chart showing actual flow test results of the present invention.

[Explanation of symbols]

1... Valve body 2...Inlet channel 3...Outlet channel 4...Bulkhead 5...Opening 10...Shutoff valve 11...Seating part 12...Control valve 12a...Trim section 14...Orifice 15...Valve seat part 16, 16a, 16b...Shutoff valve 17...Diaphragm 20...Valve seat

Claims (2)

[Claims] 1. A partition wall provided between an inlet flow path and an outlet flow path inside a valve body to curve the flow direction, and an opening provided in the partition wall to communicate the inlet flow path and the outlet flow path. and a shutoff valve disposed opposite to the opening,
The diameter of the opening increases in a curved manner toward the shutoff valve, and the lower end of the shutoff valve is located on the expanded diameter side of the opening and is coaxial with the axis of the opening. A control valve having a flange that forms an orifice with the inner circumferential surface of the opening is protruded, and the shutoff valve is movable up and down and has a lower end surface formed around the opening. A control valve characterized in that it can come into contact with. 2. The control valve comprises a body and a flange provided at the tip thereof, the flange has a vertical cross-sectional shape consisting of a combination of a square and a trapezoid, and the diameter of the body is: D1 Maximum diameter of the flange: D2 Maximum diameter thickness of the flange:
t When the angle of inclination connecting the maximum diameter of the collar and the body is θ, the following relationships are simultaneously established: 0.1≦D1 /D2 ≦0.7 0<t/D2 ≦0.15 0°≦θ≦45° 2. A control valve according to claim 1, wherein the control valve is configured to