JP2901354B2 - Control valve - Google Patents

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 for a fluid transport pipe in which a flow rate needs to be adjusted.

[0002]

2. Description of the Related Art In a conventional control valve having a valve plug and a valve seat as shown in FIG. 6, when controlling a flow rate of a fluid in a low opening region, that is, in a control in the vicinity of the lower limit of the rangeability of the valve, Fluid cavitation generated by fluctuations in pressure conditions before and after the valve locally erodes the valve plug and valve seat, and this erosion increases the amount of fluid leakage when the valve is closed, making precise control difficult and There was a problem that it became unusable in a while.

In view of the above, various proposals have been made in the past for the purpose of preventing fluid leakage at the time of valve closing due to the occurrence of cavitation. I have. The control valve disclosed in the publication includes a small-diameter portion adjacent to a valve seat, a vertical wall portion larger than the small-diameter portion, and a trumpet-shaped enlarged-diameter portion in which a hole wall expands toward the downstream side. A valve plug having two body parts, large and small, is provided in a vertically movable manner with respect to the inner hole consisting of: The flow rate is controlled by the operation of the valve plug at the peripheral surface of the large body portion or at the minimum opening formed by the seating portion and the inner hole.

[0004]

However, in such a conventional control valve, in order to completely close the valve, it is necessary to rub the seating portion and the valve seat portion by lapping so that the contact surface is adjusted. Therefore, there is a problem that not only is processing troublesome and high precision is required, but also the contact surface is worn out due to repetition of opening and closing operations of the valve, and it becomes impossible to close the valve.

[0005] The flow characteristics of the control valve are obtained by changing the area of the minimum opening formed by the inner hole and the valve plug. Therefore, it is difficult to easily obtain the flow characteristics as designed because of the shape easily affected by the resistance due to the above-mentioned resistance, and it is difficult to increase the rangeability. SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a control valve capable of improving the closing function of the control valve over a long period of time and performing flow control over a wide range. is there.

[0006]

The structure of the present invention for solving the above-mentioned problems will be described with reference to FIG. 1 corresponding 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 and bending the flow direction, and the inlet flow path 2 and the outlet provided in the partition wall 4. An opening 5 for communicating with the flow path 3;
And a closing valve 10 disposed opposite to the opening, and the opening 5 is enlarged in a gentle curved shape toward the closing valve 10 side, and a lower end of the closing valve 10 is provided with the opening 5 is a control valve which is located on the radially enlarged side and coaxial with the axis of the opening 5 and has a flange 12a which forms an orifice 14 with the inner peripheral surface of the opening 5. 12 is provided so as to protrude, and the closing valve 10 can move up and down, and a lower end surface 11 of the closing valve 10 can come into contact with a valve seat 15 formed around the opening 5.

Further, in the present invention, as shown in FIG. 4, the control valve 12 has a body 12b and a flange 12 provided at the tip thereof.
consists as a, the flange portion 12a is a combination of the longitudinal section is square and a trapezoid, the diameter of the body: the maximum diameter of D ₁ flange portion: D ₂ flange portion of maximum diameter thickness: t-collar portion When the inclination angle between the maximum diameter portion and the trunk portion is θ, the relationship of 0.1 ≦ D ₁ / D ₂ ≦ 0.7 0 <t / D ₂ ≦ 0.15 0 ° ≦ θ ≦ 45 ° is simultaneously established. It is specially formed
It is a sign.

By forming a control valve so as to satisfy these relationships simultaneously, a flow rate characteristic designed in advance can be obtained with high accuracy. On the other hand, if it is out of the above range, it becomes difficult to obtain the flow characteristics with high accuracy. The material of the control valve of the present invention may be plastic or metal, and is not particularly limited. Further, the direction of the inflow and outflow of the fluid is not limited, and the fluid can be introduced from either side of the control valve, and there is no difference in the adjustment function.

[0009]

In the present invention having the above-described structure, the fluid flowing through the inlet channel 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 channel 3
Leaks to Here, when the closing valve 10 is moved in the direction of the opening 5, the control valve 12 also moves following the movement of the closing valve 10, and the orifice 14 formed between the flange 12 a and the inner peripheral surface of the opening 5. Since the area of the fluid becomes smaller, the flow rate of the fluid decreases.
Conversely, if the closing valve 10 is moved in a direction away from the opening 5, the area of the orifice 14 is increased and the flow rate of the fluid is increased.

[0010] Since the flow rate of the fluid is adjusted in this manner, the valve-specific flow rate characteristic designed in advance can be easily obtained by changing the shape of the inner peripheral surface of the opening 5. Further, if the closing valve 10 is further moved in the direction of the opening 5, the state immediately before the closing is reached. At this time, the pressure on the upstream side of the control valve 12 firstly increases in the space between the control valve 12 and the closing 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. And the occurrence of cavitation is suppressed.

When the closing valve 10 is further moved in the direction of the opening 5, the lower end surface 11 of the closing valve 10 finally comes into contact with the valve seat 15 around the opening 5 and is pressed. The space between the outlet channel 3 and the outlet channel 3 is completely closed, and the flow of the fluid is stopped.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a valve main body, in which a partition wall 4 for partitioning an inlet channel 2 and an outlet channel 3 is provided. A curved flow path is formed between the flow paths 2 and 3. Further, a valve chamber 8 is formed in the valve body 1 in a direction perpendicular to the axis of the inlet channel 2 and the outlet channel 3, and a closing valve 10 is provided in the valve chamber 8.

The partition 4 is provided with an opening 5 for communicating the inlet channel 2 and the outlet channel 3, and this opening 5 is formed through a contraction tube 13 screwed to the partition 4. Things. The inner peripheral surface of the opening portion 5 toward the closing valve 10 side Nadara
The diameter is expanded in a kana curve shape. The contraction tube 13 has a valve seat portion 15 made of a sealing elastic body fitted and bonded to the upper outer peripheral surface thereof, and is provided on the partition wall 4 so as to communicate the inlet channel 2 and the outlet channel 3. The valve seat 15 is screwed and bonded so as to sandwich it. In the present embodiment, the opening 5 is provided by screwing the contraction tube 13 into the valve body 1, but may be provided by directly opening the partition 4.

The closing valve 10 is provided integrally with the lower end of the valve shaft 9 held by the lid 7 fixed to the upper part of the valve body 1 so that the axis coincides with the axis of the opening 5. It is held movably forward and backward in a valve chamber 8 formed by a neck portion 6 located at an upper portion of the valve body 1. An annular seating portion which can be brought into contact with the valve seat portion 15 around a lower end portion of the closing valve 10.
11 are formed.

Reference numeral 12 denotes a control valve, which is screwed to the lower end of the shut-off valve 10 so that the axis of the opening 5 coincides with the axis thereof, and is located between the inner peripheral surface of the opening 5 and Orifice 14
Has a flange portion 12a that forms The flange shape of the control valve of this embodiment is as follows: D ₁ / D ₂ = 0.7, t / D ₂ = 0.07, θ = 45
°. (See FIG. 4) The control valve 12 may be provided integrally with the lower end of the shut-off valve 10. Further, the shape of the flange portion 12a is not limited to this embodiment, but may be a disk shape or an inverted truncated cone shape. The shape of the present embodiment is an example of a suitable shape among them.

The operation of the control valve of the present embodiment having the above-described structure is as follows. In FIG. 1, the fluid that has flowed in through the inlet channel 2 is supplied to the opening 5 and the flange 12 a of the control valve 12.
And flows out to the outlet flow path 3 through the orifice 14 formed by. Here, when the closing valve 10 is moved in the direction of the opening 5 via the valve shaft 9 by the operation of the drive unit or the manual operation by the automatic control device, the control valve 12 moves accordingly. Accordingly, the area of the orifice 14 formed between the flange 12a of the control valve 12 and the inner peripheral surface of the opening 5 becomes smaller, so that the flow rate of the fluid decreases. Conversely, when the closing valve 10 is moved in the direction away from the opening 5, the area of the orifice 14 is enlarged by the opposite operation, and the flow rate of the fluid increases.

Since the flow rate of the fluid is adjusted by such an action, the pre-designed valve specific flow rate characteristic can be easily obtained by changing the shape of the inner peripheral surface of the opening 5. In addition, in an arbitrary opening degree state as shown in FIG. 1, when the fluid passes through the orifice 14, 0.1 ≦≦ as shown in FIG.
D ₁ / D ₂ ≦ 0.7, 0 <t / D ₂ ≦ 0.15, 0 ° ≦ θ ≦ 45
By forming the control valve 12 so that the relationship of ° is simultaneously established, the flow line of the fluid is sharply separated by the flange portion 12a as shown in the figure, so that the resistance due to the viscosity of the fluid is removed, and mainly only the pressure resistance It acts before and after the flange 12a.

Accordingly, since the flow 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 substantially the same as a well-known theoretical equation.

[0019]

(Equation 1)

(Q: flow rate, α: flow coefficient, A: orifice opening area, H: differential pressure before and after the orifice). Therefore, a pre-designed valve-specific flow characteristic can be obtained with extremely high accuracy, and flow control can be performed over a wide range from a minute flow to a large flow. On the other hand, when the closing valve 10 is further moved in the direction of the opening 5 from the state of FIG. 1, the state immediately before the closing as shown in FIG. 2 is obtained.

Now, in this state, the upstream side of the control valve 12
Pressure is P₁, A space formed between the control valve 12 and the closing valve 10
Pressure of part_Two, The pressure in the outlet channel 3_ThreeAnd this
R ₁, P_TwoAnd P_ThreeIn between, P₁> P_Two, P_Two> P_Three
The relationship of P₁−P_Two= ΔP₁, P_Two−P_Three= Δ
P_TwoAnd P₁−P_Three= ΔP_ThreeThen ΔP_Three= ΔP
₁+ ΔP_TwoIt is clear that holds.

That is, the fluid does not cause a pressure drop of ΔP ₃ in one step, but gradually generates a pressure drop in two steps of ΔP ₁ and ΔP ₂ , thereby suppressing the occurrence of cavitation. When the closing valve 10 is further moved in the direction of the opening 5, the seating portion 11 formed at the lower end of the closing valve 10 finally becomes a valve seat 15 provided around the opening 5 as shown in FIG. And is pressed. Therefore, the space between the inlet flow path 2 and the outlet flow path 3 is completely closed, so that the flow of the fluid is stopped and the valve is completely closed.

With the above operation, the increase or decrease of the fluid flow rate is adjusted, and the valve is closed. An actual flow test was performed under the following conditions using a control valve having a diameter of 15 A having the structure shown in FIG. 1 and a control valve in which the control valve 12 in the control valve 12 was changed in six types. The same was done for conventional products. [Conditions] Fluid: water Temperature: 25 ° C. Pressure difference before and after the valve: 0.7 kgf / cm ² The results are shown in Table 1 and FIG.

[0024]

[Table 1]

The table is 1, the maximum error from the singlet requirements designed value in (change condition) only the actual flow test of the regulating valve having a control valve varying results (corresponding to the linear A ₂ in FIG. 7) ( %) (corresponding to a ₃ parts in FIG. 7) are shown. As can be seen from Table 1, the control valve of No. 4 (product of this embodiment) shows the smallest value of 35%, which indicates that the flow rate characteristics are obtained with the highest accuracy. NO.2,
Although the control valves 5 and 8 are the same product, the maximum error of the conventional product is approximately
50% is smaller than (corresponding to ₃ parts B in FIG. 7), this condition is determined as the upper limit superior to conventional products.

On the other hand, the control valves of Nos. 3, 6, and 9 show values close to those of the conventional products, and the flow characteristics cannot be obtained with high accuracy under these conditions. That is, as shown in FIG. 4, the shape of the control valve 12 is set to 0.1 ≦ D ₁ / D ₂ ≦ 0.7, 0 <t / D ₂ ≦
It can be seen that when the shape is such that 0.15, 0 ° ≦ θ ≦ 45 °, the accuracy is remarkably improved as compared with the conventional product.

FIG. 7 shows a control valve (the above-mentioned NO.
4) and a flow characteristic table of the conventional product are shown. As can be seen from the figure, the rangeability of the conventional product (curve B _{1 in the} figure) is 20: 1.
Compared with this, the rangeability of the control valve of the present invention (curve A _{1 in the} figure) was greatly improved to 60: 1, and control was possible over a wide range from a small flow rate to a large flow rate. The deviation from the design value (the linear portions A ₂ , B _{2 in the} figure) was smaller than that of the conventional product, and the flow 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 the present embodiment has two split pieces 16a and 16a.
The diaphragm 17 has a diaphragm 17 sandwiched by a closing valve 16 made of b, and prevents a fluid or foreign matter from entering a sliding portion 18 between the valve body 1 and the closing valve 16. The operation and effect are the same as those of the control valve having the structure shown in FIG.

[0029]

As described above, since the control valve according to the present invention has the above-described structure, 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, flow characteristics can be accurately obtained, and control can be performed over a wide range from a minute flow rate to a large flow rate.

Since the occurrence of cavitation in the valve seat and the seat can be prevented, the seat in the valve seat is not eroded at all, and leakage of fluid when the valve is closed can be reliably prevented. Can be improved in durability. In addition, since cavitation can be prevented from occurring in the control valve and the opening, high-precision control can be performed over a long period of time.

Since there is no troublesome tapered seating portion or valve seat portion that requires processing, rubbing, or the like, it can be manufactured easily and inexpensively.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view of a main part showing a state immediately before closing of a control valve in FIG. 1;

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

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

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

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

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Valve body 2 ... Inlet flow path 3 ... Outlet flow path 4 ... Partition wall 5 ... Opening 10 ... Closure valve 11 ... Seating part 12 ... Control valve 12a ... Flange part 14 ... Orifice 15 ... Valve seat part 16, 16a, 16b … Closed valve 17… Diaphragm 20… Valve seat

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tomio Wada 2-5955, Nosemachi, Nakanobe, Miyazaki Prefecture Inside Asahi Organic Materials Industry Co., Ltd. (56) References Sho-sho 59-34073 (JP, A) Jiko 43-19745 (JP, Y1) Jiko 13318 (Taisho 14) (JP, Y1 T) (58) Fields investigated (Int. Cl. ⁶ , DB name) ) F16K 1/34 F16K 1/44 F16K 47/02

Claims (1)

(57) [Claims] 1. A partition provided between an inlet flow path and an outlet flow path inside a valve body to bend a flow direction, and an opening provided in the partition and communicating the inlet flow path and the outlet flow path. And a closing valve disposed opposite to the opening,
The opening is gently curved toward the shut-off valve, and is arranged at the lower end of the shut-off valve on the enlarged diameter side of the opening and coaxial with the axis of the opening. In addition, a control valve having a flange forming an orifice with the inner peripheral surface of the opening is protruded, and the shut-off valve is vertically movable and a lower end surface thereof is formed around the opening. The control valve comprises a body and a flange provided at the tip thereof, and the flange is formed by a combination of a square and a trapezoid. has, and barrel diameter: maximum diameter of D ₁ flange portion: D ₂ flange portion of maximum diameter thickness: inclination connecting the maximum diameter portion and the body portion of t the flange portion: 0.1 when the θ A control valve characterized in that a relationship of ≦ D ₁ / D ₂ ≦ 0.7 0 <t / D ₂ ≦ 0.150 0 ° ≦ θ ≦ 45 ° is simultaneously satisfied.