JPH04145269A - Seat ring for butterfly valve - Google Patents

Abstract

PURPOSE:To increase the extent of mechanical strength in and around a boss part as well as to secure such a butterfly valve that is provided with a flow-controllable angle seat part by widening this angle seat part of an annular seat ring in proportion as coming close to the boss part, and making the angle seat part narrower toward the central part between two boss parts. CONSTITUTION:A pair of boss parts 4, 4 around a valve stem through hole 3a are formed in an annular seat ring 12a being attached to the inner surface of a valve body, and a section angle seat part 12 for pressing it to a valve element peripheral edge at time of valve closing is formed in the space between these paired boss parts 4, 4 in succession along the circumferential direction. The angle seat part 12 is widened so as to increase their mechanical strength in proportion as the boss part 4, is approached and this seat part 1 is narrowed toward the center between both these boss parts 4 and 4, then the valve element peripheral edge and the angle seat part 12 are successively closed to the central part from these boss parts 4 stepwise at time of valve closing. When a valve element is closing, the valve element peripheral edge comes into contact with the angle seat part successively toward the central part in stages from the boss part of the seat ring being contacted at all times, thus a flow rate is successively controlled stepwise by means of valve opening.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a seat ring for a butterfly valve, and in particular,
The present invention relates to a seat ring having a chevron-shaped seat portion.

[Conventional technology]

Conventionally, the valve body is interposed between the entire inner peripheral surface of a hollow cylindrical body (valve body) made of a rigid material and the peripheral edge of a disc-shaped valve body made of a rigid material and rotatably supported within the body. An annular seat ring made of an elastic material is formed into a chevron shape with an arcuate cross section, so that the valve body closes from the open position and rotates 90 degrees from the position where it starts contacting the annular seat ring to the fully closed position. By reducing the rotation angle of the valve body, it is possible to prevent the annular seat ring from being pulled when the so-called valve body closes, and
A valve having a chevron-shaped cross section lowers the repulsion spring constant when the valve body bites into the seat ring when the valve body closes, thereby reducing rotational torque, which was previously developed by the applicant. (Refer to Japanese Utility Model Publication No. 52-30600), and furthermore, the entire circumference of the valve body except for the vicinity of the boss portion is brought into contact with the inner surface of the seat ring having a chevron-shaped cross section as described above at the same time, thereby achieving a sealing effect. and rotational torque at the same time, and waste torque (rotation caused by all points on the circumference of the valve body, except for the point farthest from the valve stem, biting into the chevron seat part earlier) A device that eliminates the torque (torque) has already been developed by the present applicant (see Japanese Patent Publication No. 58-25911).

In this case, (i) the width of the chevron-shaped seat portion of the seat ring is set to the minimum width in the vicinity of the boss portion within a range that does not impair the mechanical strength of the seal, and (ii) the width between the two boss portions of the chevron-shaped seat portion is The width of the curved line expressed by a cosine function with the center of the boss section as the starting point increases toward the center of the boss section.

[Problem to be solved by the invention]

As shown in FIG. 6, the seat ring of the butterfly valve, which has a curved shape expressed by a cosine function and which has already been developed by the applicant, is elastic at the entire periphery of the valve body 1 at the valve opening degree α. Since the annular seat ring 2a contacts (abuts) the inner surface of the chevron-shaped seat portion 2 at the same time, there is a problem that fluid control becomes impossible at an angle smaller than a set angle, for example, close to fully open.

Generally, in the case of a butterfly valve, when the valve opening is 70 degrees or more, the flow characteristics hardly change, and in order to widen the control range from fully closed to fully open, the closer the fully closed position is to 00, the more advantageous it is. It is.

Further, the boss portion of the seat ring 2a (not shown), which corresponds to the vicinity of the periphery of the pair of through holes through which the valve rod 3 supporting the valve body 1 is passed, is always in pressure contact with the periphery of the valve body 1. , the rotation of the valve body 1 causes torsional stress, which is an important problem in terms of strength.

In addition, as shown in the front view of the valve body in Fig. 5, the closing torque is the length between an arbitrary point P on the circumference of the valve body 1 and the center point S when it rotates around the central axis C of the valve body. (Arm) PK = I!
= r cos θ (where r is the valve radius and θ is the phase angle), so for example, 10 kg/c
If the crushing width of the chevron-shaped sheet 2 (Fig. 6) of the rubber seat ring 2a to close the pressure of t is l mm, then
A force that crushes the boss part B (θ=90°) by 1 mm and a part A of the tip of the valve body corresponding to the center part between both the upper and lower boss parts B (
When compared to the force that crushes 1 mm at θ=0°), the latter is stronger than l(
As the closing torque increases as the arm) becomes larger, an actuator (not shown) that drives the valve body 1 needs to have a large load capacity, which is uneconomical. The above-mentioned tendency was noticeable in sheet links whose width was widened toward the center of the sheet with a curved shape represented by a cosine function.

SUMMARY OF THE INVENTION An object of the present invention is to provide a butterfly valve having a chevron-shaped seat portion that has high mechanical strength near the boss portion and is capable of controlling the flow rate.

Moreover, the second invention aims at controlling the flow rate in proportion to the valve opening degree.

[Means to solve the problem]

In order to achieve the above object, the first aspect of the present invention provides a valve made of a rigid material that is rotatably supported within the entire inner circumferential surface of a hollow cylindrical body made of a rigid material. An annular seat ring made of an elastic material is interposed between the periphery of the valve body, and the annular seat ring always has a base of the valve stem of the valve body around each of a pair of through holes for passing the valve stem. A pair of boss portions were formed in the vicinity for pressure contact, and a chevron-shaped seat portion was formed continuously along the circumferential direction between the pair of boss portions for pressure contact with the peripheral edge of the valve body when the valve was closed. In the butterfly valve equipped with an annular seat ring, the chevron-shaped seat portion of the seat ring is made wider as it approaches the vicinity of the boss portion so as to increase mechanical strength, and the chevron-shaped seat portion is made wider toward the center between both boss portions. The second invention is characterized in that the width is narrowed, and when the valve is closed, the peripheral edge of the valve body and the chevron-shaped seat portion are brought into close contact with each other in stages from both boss portions toward the center portion. The cross-sectional area of the opening between the peripheral edge of the valve body and the chevron-shaped seat of the seat ring is increased or decreased for each degree of valve opening when the valve is closed, so that the flow rate characteristics are proportional to the degree of valve opening. It is characterized in that the peripheral edge portion and the chevron-shaped sheet portion are brought into close contact with each other in stages from both boss portions toward the center portion.

[For production]

Since the present invention is configured as described above, in the first invention, when the valve body is closed from an open state, the peripheral edge of the valve body is constantly pressed when the valve body reaches a set valve opening degree. The seat ring comes into contact with a chevron-shaped seat portion whose width is narrowed in steps from the boss portion toward the center portion, and the flow rate is accordingly controlled in steps according to the valve opening degree.

In addition, in the second invention, since the flow rate characteristics change in proportion to the valve opening degree, it is possible to create a globe valve.
It is possible to achieve control characteristics such as the following with a butterfly valve.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a drawing of a seat ring showing an embodiment of the present invention. FIG. (a) θ° ~ 90° 10
It is a sectional view at each divided position, and in the figure, the same reference numerals as those shown in FIG. 6 indicate the same or similar parts.

In the figure, the annular seat ring 12a attached to the inner surface of the main body (valve main body), not shown, has a pair of boss parts 4 around the valve stem through hole 3a, as shown in the developed view of FIG. 1(a). 4 is formed, and between the pair of boss parts 4, 4, a seat part 12 having a chevron-shaped cross section is continuously formed along the circumferential direction to be brought into pressure contact with the peripheral edge of the valve body when the valve is closed. .

The above-mentioned chevron-shaped seat portion 12 is formed when the valve opening degree is α and the phase angle of an arbitrary point P on the peripheral edge of the valve body 1 is θ in the explanatory diagrams of the operation of the valve body in FIGS. 3(a) and 3(b). , αθ, and the angle-shaped sheet portion 1 at each phase angle θ position where 08 to 90° is divided into 10 equal angles as shown in FIG. 1(a).
The cross-sectional shape of No. 2 is shown in FIG. 1(b).

In this embodiment, the opening cross-sectional area (flow passage cross-sectional area) formed by the gap between the valve body 1 and the annular seat ring 12a is
The peripheral edge of the valve body and the chevron-shaped seat portion 12 are formed so as to be brought into contact with each other so that the cross-sectional area increases or decreases proportionally for each valve opening degree α, that is, increases or decreases proportionally.

FIGS. 3(a) and 3(b) are drawings for explaining the above relationship; FIG. 3(a) is a top view of FIG. 3(b), and FIG. In the figure, 0 is the center of the valve body l, A is the tip position when the valve body 1 is in a fully closed state, B is the intersection of the valve stem center line C and the valve body 1, and P is the periphery of the valve body. Assuming that R is a point symmetrical to P with respect to B, the tip position of the valve body when the valve body 1 opens at α angle from the fully open position (α-〇 in the same figure (a)) is A', and the valve body 1 at this time
In the same figure (b), it has an elliptical shape with a major axis as 2b and a minor axis as 2a, and a''r cos α 1)=r (where r is the radius of the valve body).

Also, the area S of the circle. =πr2 Area of ellipse S 2 = yr a b = yr r
2 cosa On the other hand, the fluid passage, that is, the opening cross section when the valve body 1 opens corresponds to the area difference S between the circle and the ellipse, so S+ = So -32 = yr r2 - yrr '' cos
a='yr r2 (1-cos α) In order to obtain a cross-sectional area such that the area difference S3 corresponding to the fluid passage increases or decreases by dividing it equally according to the valve opening degree α, and to match the cross-sectional area, A portion P of the peripheral edge of the valve body at a phase angle θ position equal to the valve opening degree α is brought into contact with the chevron-shaped seat portion 12;
The curve of the chevron-shaped sheet portion 12, that is, the cross-sectional shape at each phase angle position, is determined by keeping the parallel hatched portions of the P portion and the B portion closed.

Figures 2 (a) and (b) show that the valve body l is in the fully open position with the valve opening α = 90°, and when α = 80°, the P portion of θ = 80° is in contact with the chevron-shaped seat portion 22. , finally when α=0°, θ
1(a) and 1(b) of an embodiment in which a chevron curve is formed so that the angle becomes 06 and the fully closed state is achieved.

According to this embodiment, the flow rate can be controlled over a wide range of valve opening angles.

FIG. 4 is a cross-sectional view of another embodiment showing the narrowest part of the seat ring at the center between both boss parts 4. In order to increase the mechanical strength of the core part, the boss part One mountain (radius R,) is made with the mountain shape width (Wo) at the base of 4, and on top of that, the mountain shape sheet part 12 (radius R,
) has been established.

Note that the radius R is <R8.

In both of the above embodiments, a structure in which the flow rate can be controlled in proportion to the valve opening degree has been described, but the valve opening degree and the controlled flow rate can be set arbitrarily other than in a proportional relationship. .

〔Effect of the invention〕

As explained above, according to the present invention, the chevron-shaped seat portion of the annular seat ring is made wider as it approaches the vicinity of the boss portion, and the width of the chevron-shaped seat portion is narrowed toward the center between both boss portions, When the valve is closed, the peripheral edge of the valve body and the chevron-shaped seat are brought into close contact with each other in stages from both bosses toward the center, thereby achieving the following effects.

(i) In the conventional device already developed by the present applicant, if the fully closed position where the valve body contacts the chevron-shaped seat portion simultaneously over the entire circumference is set to a valve opening of 30° or less, the seat near the boss While there is almost no difference between the width and the seat width at the center, in the present invention, even if the valve opening is 30 degrees or less, the center portion is narrowed to a width slightly wider than the edge thickness around the valve body. Not only is this possible, but also the mechanical strength near the boss portion can be increased.

(ii) Since the flow rate can be controlled within a range smaller than the set valve opening degree, the butterfly valve can be used as a flow rate control valve.

(iii) Control characteristics similar to those of a globe valve can be achieved with a butterfly valve by increasing and decreasing the opening cross-sectional area between the peripheral edge of the valve body and the chevron-shaped seat of the seat ring in proportion to when the valve is closed. .

Therefore, the valve body driving section may be of a general proportional control type, so that the cost can be reduced.

[Brief explanation of drawings]

FIGS. 1(a) and (b) are a developed view of an annular seat ring showing an embodiment of the present invention, and sectional views at each position phase-divided every 10′, FIGS. 2(a) and (b) are similar drawings to FIGS. 1(a) and (b) showing other embodiments, and FIG.
Figures (a) and (b) are explanatory diagrams of the action of the valve body with respect to Figures 1 (a) and (fb), Figure 4 is a cross-sectional view of main parts showing another embodiment of the present invention, and Figures 5 and 6. FIG. 2 is an explanatory diagram showing the contact relationship between the valve body and the chevron-shaped seat portion of the seat ring. 1... Valve body, 2.12.22... Chevron seat part, 2
a. 12a, 22a...Seat ring, 3...Valve stem, 3
a...Valve stem hole, 4...Boss part, α...Valve opening degree, θ
...Phase angle.

Claims (1)

[Claims] 1. Between the entire inner circumferential surface of the hollow cylindrical body made of a rigid material and the peripheral edge of the valve body made of a rigid material rotatably supported within the body, there is made of an elastic material. An annular seat ring is interposed therebetween, and the annular seat ring has a pair of boss portions around each of a pair of through holes through which the valve stem is passed, and which is in constant pressure contact with the vicinity of the base of the valve stem of the valve body. In the butterfly valve, the butterfly valve is equipped with an annular seat ring in which a chevron-shaped seat ring is continuously formed along the circumferential direction between the pair of boss parts for bringing the valve body into pressure contact with the peripheral edge of the valve body when the valve is closed. The chevron-shaped seat part of the ring is made wider as it approaches the vicinity of the boss part so as to increase its mechanical strength, and the width of the chevron-shaped seat part is narrowed toward the center between both boss parts, so that when the valve is closed, the periphery of the valve body 1. A seat ring for a butterfly valve, characterized in that the chevron seat portion and the chevron seat portion are brought into close contact with each other in stages from both boss portions toward the center portion. 2. The opening cross-sectional area between the peripheral edge of the valve body and the chevron-shaped seat portion of the seat ring is increased or decreased for each valve opening degree when the valve is closed,
A claim characterized in that when the valve is closed, the peripheral edge of the valve body and the chevron-shaped seat portion are brought into close contact with each other in stages from both boss portions toward the center portion so that the flow rate characteristic is proportional to the valve opening degree. Seat ring of the butterfly valve described in 1.