JPS6230628Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention uses a so-called pressure relief function and a seal that effectively release abnormal pressure increase generated in the cavity (valve chamber) of a ball valve to the flow path. This invention relates to a valve seat for a ball valve with improved performance.

[Conventional technology]

If the pressure inside the body cavity of the ball valve increases abnormally due to a rise in temperature or vaporization of the fluid, the valve seat, body, balls, etc. may be deformed or damaged, resulting in a situation where the function of the ball valve is reduced or lost.

Various ideas have been devised as means for preventing the above-mentioned problems, and representative ones include those described in Japanese Utility Model Application Publication No. 56-82360 and Japanese Utility Model Application Publication No. 56-82361. In the invention described in Japanese Utility Model Application Publication No. 56-82360, a circumferential portion of the tongue-shaped portion of the valve seat that is brought into pressure contact with the ball surface is formed thin so as to be easily elastically deformed. It tries to escape by pushing this thin tongue-like part apart.

However, in this method of forming the tongue-like part thinly, since a part of the tongue-like part in the circumferential direction is made thinner, the pressing contact surface of the tongue-like part with the ball surface is weak, and furthermore, the tongue-like part has a weak pressure contact surface with the ball surface. This causes excessive permanent deformation of the valve seat, resulting in a decrease in sealing performance, and there is a need to replace the valve seat, etc., as soon as possible.

In addition, in the device described in Japanese Utility Model Application Publication No. 56-82361, a thin piece is formed on the side surface of the valve seat body that comes into contact with the stepped part of the valve body, and abnormal pressure rise inside the cavity is caused by the contact of this thin piece with the stepped part. It seems to be trying to spread its surface and escape. However, this thin section deforms under pressure not only when the pressure increases abnormally, but also at any time.Especially when the pressure increases abnormally, it deforms excessively, impairing the sealing performance in this area, and requiring early replacement of the valve seat, etc. There is.

[Problem that the invention attempts to solve]

As described above, the problem that this invention aims to solve is that a valve seat that has a pressure relief function becomes a valve seat that has poor sealing performance and durability, and must be replaced at an early stage. It is a point.

[Means for solving problems]

In order to solve the above problems, the present invention adopts the following configuration.

In an annular valve seat installed between a step formed inside the body of the ball valve and a ball having a through hole, a shoulder is formed on the radially outer side of the valve seat body, and on the ball side of the shoulder, A tapered surface spaced apart from the ball surface is formed, and a valve seat engagement surface is formed on the body side of the shoulder portion to engage with a step engagement surface perpendicular to the flow path of the body of the step portion. A tongue is formed on the inside of the valve seat body in the radial direction, a tapered surface is formed on the ball side of the tongue to come into contact with the ball surface on the inside in the radial direction, and a radial portion is formed on the body side of the tongue. a recessed portion having a tongue plane spaced apart from the step engagement surface and parallel to the valve seat engagement surface on the inside in the direction, and a shoulder on the outside in the radial direction that is coplanar with the tongue plane. A groove part is formed that cuts into the shoulder part halfway up the shoulder part, and a part of the annular valve seat engaging surface that is radially inward from the radially outermost position of the groove part is formed as a stepped surface or inwardly facing part. A separating surface spaced apart from the step engagement surface was formed as a tapered surface.

[Function]

If the pressure inside the ball revolve cavity increases abnormally, this pressure will spread out the contact surface of the tongue-like part of the valve seat body with the ball, since the shoulder of the valve seat is separated from the ball surface. act.

The surface of the tongue opposite to the ball contact surface, that is, the body-side surface, has a flat tongue formed on the inside of the tongue in the radial direction, spaced apart from the step engagement surface and parallel to the valve seat engagement surface. A groove is formed by cutting into the flat shoulder part halfway in the shoulder part toward the shoulder part on the outside in the radial direction, and to put it simply, this part forms a tongue part that is longer than the other tongue parts. As a result, the ball contact surface can be expanded with lower cavity pressure than other tongue-like parts. Since these grooves are formed to cut into positions suitable for releasing abnormal pressure increase, the abnormal pressure increase can be released without deforming or damaging the valve.

Moreover, since the above-mentioned groove is not cut into the tongue-like part that contacts the ball, there is no thin part in the circumferential direction on the radially inner side of the tongue-like part where the tongue-like plane is provided, and the thickness is uniform. , the pressure contact force with the ball surface is strong, and the tongue-shaped portion does not deform excessively and deteriorate the sealing performance.

Furthermore, since the part of the annular engagement surface located radially inward from the radially outermost position of the groove is separated from the step engagement surface as a step surface or a separation surface of an inwardly tapered surface, the valve Even if the tongue-like part of the seat body is pushed by the ball surface and a rotational force is applied that causes the shoulder part to approach the ball surface, the strongest contact between the stepped part and the valve seat body is as follows. This is the intersection line between the valve seat engaging surface and the stepped surface or inwardly tapered surface, and since this line is the outermost position in the radial direction of the groove, it is completely circular and will not be cut by the groove. There is no need to worry about leakage from between the step and the valve seat.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of the ball valve according to the present invention, FIG. 2 is a partially enlarged sectional view showing the valve seat portion of the present invention, and FIG. 3 is a partially enlarged sectional view showing another example of the valve seat portion. Figure 4 shows a perspective view of the valve seat, and 1 in the figure is the body of the valve, with the inflow side (primary side) 2 on one side of the body 1 and the outflow side (secondary side) on the other side.
form 3. 4 is a ball rotatably provided in the valve chamber of the body 1 with a stem 5 glued to the upper part thereof, and is provided so as to communicate fluid through a through hole 6 formed in this ball 4, while being in a closed state. for,
By rotating the handle 7 and the like, the ball surface 4a of the ball 4 shuts off the fluid.

Reference numeral 8 designates a pair of annular valve seat bodies mounted between the stepped portions 9, 9 formed inside the body 1 and the ball 4, and a shoulder portion 11 is formed on the outside of the valve seat body 8 in the radial direction. However, on the ball 4 side of this shoulder portion 11,
An annular tapered surface 11 spaced apart from the ball surface 4a
a, and a gap S is provided between the tapered surface 11a and the ball surface 4a, and the valve seat engaging surface 12 formed on the body 1 side of the shoulder portion 11 is perpendicular to the flow path of the body of the stepped portion 9. The step engagement surface 12a is engaged with the step engagement surface 12a.

Further, a tongue-shaped portion 1 is provided on the radially inner side of the valve seat body 8.
A tapered surface 11b is formed on the ball 4 side of the tongue 10 to contact the ball surface 4a on the radially inner side, and a stepped surface 11b is formed on the body 1 side of the tongue 10 on the radially inner side. A recessed portion 10b is formed having a tongue-shaped portion flat surface 10a spaced apart from the valve seat engaging surface 12a and parallel to the valve seat engaging surface 12.

Reference numeral 13 denotes a space, and this space 13 is formed by the tapered surface 11a and tapered surface 11b of the valve seat body 8 and the ball surface 4a by the tongue-shaped portion 10 coming into contact with the ball surface 4a on the inside in the radial direction. It is a space where there is no contact.

A cavity 14 is defined between the body 1, the pair of valve seat bodies 8, and the ball surface 4a, and the space 13 and the cavity 14 are always in communication.

Reference numeral 15 denotes a groove formed on the body side of the tongue 10, and the groove 15 is flush with the tongue plane 10a of the tongue 10 and extends toward the shoulder 11 on the outside in the radial direction. This is a groove that cuts into the middle of the hole. Although the grooves 15 are provided above and below the valve seat body in FIG. 4, the grooves 15 are not limited to this, and any number of grooves may be provided at appropriate positions. By changing the pressure as appropriate, the pressure within the cavity 14 can be arbitrarily set within an allowable range.

Reference numeral 16 denotes an annular separating surface formed on the valve seat body 8 so as to be spaced apart from the stepped engagement surface 12a, and this separating surface 16 is located radially inward from the radially outermost position A of the groove portion 15. Annular valve seat engagement surface 12
It is formed in the part. The separation surface 16 in FIG. 2 is a stepped surface 16a, and the separation surface 16 in FIG. 3 is an inwardly tapered surface 16b.
That is.

Next, the operation of the above embodiment will be explained.
In the valve open state shown in FIG. 1, when the ball 4 is rotated so that the through hole 6 of the ball 4 is perpendicular to the flow path, the fluid is closed. At this time, the valve seat body 8 on the secondary side 3 is pressed against the ball 4 by the fluid pressure, and the contact zone of the tongue 10 comes into stronger sealing contact with the ball surface 4a, and the valve seat body 8 on the primary side 2 The tongue portion 10 of the main body 8, which is elastically deformed, is in secure sealing contact with the ball surface 4a.

In both the open and closed states,
When the pressure of the fluid in the cavity part 14 increases abnormally due to temperature rise or vaporization, this abnormal pressure increase reaches the space part 13 from the gap S formed between the tapered surface 11a of the shoulder part 11 and the ball surface 4a. . Furthermore,
This abnormal pressure increase spreads the contact zone with the ball surface 4a of the tongue portion 10, which has the groove portion 15 which is more easily separated from the ball surface than other portions due to the formation of the groove portion 15, and flows out into the flow path of the valve. The pressure within the cavity 14 is maintained within an acceptable range. In this case, since the groove portion 15 is not formed on the tongue portion 10 that contacts the ball surface 4a, the radially inner portion of the tongue portion 10 provided with the tongue portion 10a has no thin portion in the circumferential direction. It has a uniform thickness, and the tongue portion 10 partially deforms excessively and creeps due to pressure contact with the ball surface 4a or due to cavity pressure when abnormally increased pressure flows out. Therefore, there is no deterioration in sealing performance, and the product has excellent durability.

Further, a separating surface 16 such as a stepped surface 16a or an inwardly tapered surface 16b is provided in a portion of the annular valve seat engaging surface 12 that is radially inward from the outermost position A in the radial direction of the groove portion 15. Since the gap C is formed between the ball 4 and the separating surface 16, the ball 4 and the stepped portions 9, 9
When the valve seat main body 8 is mounted between the valve seat body 8 so that the tongue-shaped portion 10 elastically deforms and presses the ball surface 4a, the ball 4 of the valve is closed and the ball 4 is pushed back by fluid pressure. The tongue-shaped portion 10 formed on the valve seat main body 8 of the secondary side 3 is pushed more strongly than the repulsive force caused by the elastic deformation when the ball 4 is assembled into the body 1, and the valve seat body 8 is pressed toward the next side. A counterclockwise rotational force is applied to the main body 8.

FIG. 6 is a partially enlarged sectional view showing a state in which the valve seat main body 8 has been slightly rotated from the state shown in FIG. 2 by the above rotational force.

Note that in an actual valve, the valve seat body 8 does not rotate as markedly as shown in FIG. 6, but for the purpose of explanation, a state in which it rotates slightly is shown.

In the state shown in Fig. 6, the valve seat main body 8 is connected to the body 1.
The part that is in contact with the stepped engagement surface 12a is at position A.
Only. That is, on the body 1 side of the valve seat main body 8, the radially inner side of the position A is the step surface 16a, which is the separation surface, and the tongue-shaped portion plane 10a,
Both are spaced apart from the stepped engagement surface 12a, and even if the valve seat body 8 rotates slightly counterclockwise, the portion of the valve seat body radially inward from position A Also, the radially outer side of position A is the valve seat engagement surface 12 that engages with the step engagement surface 12a, and the valve seat body 8 rotates slightly in the counterclockwise direction. Accordingly, the step engagement surface 12a
move away from As a result, the valve seat main body 8 is in contact with the step engagement surface 12a of the body 1 only at position A.

Position A is the outermost position in the radial direction of the groove portion 15, and is also a position on the outer circumferential line of the annular separation surface provided radially inward from this position, that is, the stepped surface 16a. is the fourth
As can be clearly seen in the figure, it forms a perfectly circular line spanning the entire circumference of the valve seat body 8.

Therefore, as shown in FIG.
Even if the valve seat body 8 rotates slightly counterclockwise,
contacts the step engagement surface 12a of the body 1 along a perfectly circular line passing through A, and since the contact area at this contact line is extremely small, a high surface pressure is generated and the step engagement surface 12a The sealing action is reliably performed without the so-called back leakage phenomenon occurring between the valve seat body 8 and the valve seat body 8.

Furthermore, the valve seat body 8 of the primary side 2 in the valve open state
Also, when assembling the ball 4 into the body 1, the tongue 10
is pressed against the ball surface 4a, and the same rotational force as that on the secondary side 3 is acting on the valve seat body 8. However, similarly to the valve seat body 8 on the secondary side 3, the valve seat body 8 is pressed against the body 1.
The stepped engagement surface 12a and the valve seat body 8 are in contact with each other along a perfectly circular line passing through A, so that so-called leakage phenomenon between the stepped engagement surface 12a and the valve seat body 8 does not occur, and sealing is ensured.

FIG. 3 is a partially enlarged sectional view of another embodiment in which the separating surface is an inwardly tapered surface 16b. For example, the operation in a state (not shown) in which the valve seat body 8 is slightly rotated by a counterclockwise rotational force from the state shown in FIG. The sealing action is reliably performed.

3 and 4 show a stepped surface 16 as a separation surface.
Fig. 5 is a partially enlarged view of the structure of the present invention in which only the separating surface is not provided, although the structure is provided with the inwardly tapered surface 16b.
Further, FIG. 7 is a partially enlarged cross-sectional view showing a state in which the valve seat body 8 is slightly rotated from the state shown in FIG. 5 by a counterclockwise rotational force.

In FIG. 7, position B is a position where the valve seat engagement surface 12 transitions to the recess 10b, and the recess 10b is formed radially inward from position B on the body 1 side of the valve seat main body 8. Therefore, even if the valve seat body 8 slightly rotates counterclockwise, the portion of the valve seat body 8 radially inward from position B does not come into contact with the stepped engagement surface 12a, and The radially outer side is the valve seat engagement surface 12 that engages with the step engagement surface 12a, and is separated from the step engagement surface 12a by slightly rotating the valve seat body 8 in the counterclockwise direction. . As a result, the valve seat main body 8 is attached to the stepped engagement surface 12.
Only position B is in contact with point a.

Position B is located at the valve seat engagement surface 12, as previously mentioned.
However, in the cross section shown in FIG. 7, the groove 15 is formed radially outward from the recess 10b, so the position B on this cross section is the position where the groove 15 inside the valve seat body 8 and not on the surface of the valve seat body 8. That is, although position B is on a circular line transitioning from the valve seat engaging surface 12 to the recessed part 10b, this circular line is cut by the groove part 15 and does not form a perfect circle. do not have. Furthermore, as can be seen from FIG. 7, the radially outermost position A of the groove 15 is slightly separated from the stepped engagement surface 12a due to the counterclockwise rotation of the valve seat body 8. That is, in the cross section shown in FIG. 7, the valve seat main body 8 and the step engagement surface 12a are not in contact with each other, so that so-called back leakage occurs.

In short, the structure of the present invention achieves the structure shown in FIG. 5 by providing a separating surface (step surface 16a or inwardly tapered surface 16b) as shown in FIGS. 2 and 3. It reliably prevents back leakage that occurs in a shape without a separating surface, and significantly improves sealing performance.

[Effects of the invention] As is clear from the above, according to the invention, the pressure relief function can be effectively exerted by the valve seat body against abnormal pressure inside the cavity, and moreover, the valve seat body can effectively exert a pressure relief function against abnormal pressure inside the cavity. It is possible to provide a valve seat for a ball valve that has significantly improved durability and sealing performance compared to a seat.

[Brief explanation of the drawing]

Figures 1 to 4 show examples of the present invention, and Figure 1 is a vertical cross-sectional view of the valve in the present invention;
Figure 2 is a partially enlarged cross-sectional view showing the valve seat part of the same as above;
FIG. 3 is a partially enlarged sectional view showing the valve seat portion of another example of the present invention, and FIG. 4 is a perspective view showing the valve seat of the present invention. Moreover, FIGS. 5 to 7 are partially enlarged sectional views shown for explaining the present invention. DESCRIPTION OF SYMBOLS 1... Body, 4... Ball, 4a... Ball surface, 6... Through hole, 8... Valve seat body, 9... Step part, 10... Tongue part, 10a... Tongue part plane, 1
0b... recess, 11... shoulder, 11a, 11b
... Tapered surface, 12 ... Valve seat engagement surface, 12a ...
Stepped engagement surface, 15... Groove, 16... Separation surface, 1
6a...Stepped surface, 16b...Inward tapered surface.

Claims (1)

[Claims for Utility Model Registration] (1) In an annular valve seat installed between a step formed inside the body of a ball valve and a ball having a through hole, a shoulder is formed on the outside in the radial direction of the valve seat body. A tapered surface spaced apart from the ball surface is formed on the ball side of the shoulder, and a tapered surface is formed on the body side of the shoulder to engage with a step engagement surface perpendicular to the flow path of the body of the step. a tongue-shaped portion is formed on the radially inner side of the valve seat body, and a tapered surface that contacts the ball surface on the radially inner side of the tongue portion is formed on the ball side of the tongue-shaped portion. , on the body side of the tongue, a recess is formed on the inside in the radial direction and has a tongue plane that is spaced apart from the step engagement surface and parallel to the valve seat engagement surface; A groove is formed in the same plane and cuts into the shoulder part halfway in the shoulder part in the radial direction, and the annular valve is located radially inward from the outermost position in the radial direction of the groove part. A valve seat for a ball valve, characterized in that a portion of the seat engagement surface is spaced apart from the step engagement surface to form a separation surface. (2) The valve seat of the ball valve according to claim 1, wherein the separation surface is a stepped surface at the valve seat engagement surface. (3) The valve seat for a ball valve according to claim 1, wherein the separation surface is an inwardly tapered surface at a portion of the valve seat engagement surface.