JPH085425Y2 - Gate valve seal structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a valve box seat that is in sliding contact with a sliding valve body.
The present invention relates to a seal structure of a sluice valve which is attached to a valve box while being prevented from coming off by a seat ring.

[Prior Art] In a conventional seal structure for a sluice valve, a valve box seat is housed in a valve box, and the valve box seat is fixed by a seat ring.

However, the above-mentioned conventional seal structure has a drawback that the sealability is deteriorated because the valve box seat is abraded over time due to the sliding contact between the valve box seat and the sliding valve body.

Further, regardless of the wear over time of the valve box seat, if the difference between the load pressures on both sides of the sliding valve body, that is, the difference between the positive pressure and the reverse pressure (negative pressure) becomes relatively large, sliding will occur due to the pressure difference. Since the valve body is biased toward the counter pressure load side, the sealing performance of the valve box seat facing the positive pressure load side of the sliding valve body deteriorates.

Therefore, a seal structure for a sluice valve, which solves these problems and improves the sealing performance, has already been proposed by the applicant of the present application (Japanese Patent Application No. 63-43212 (Japanese Utility Model Publication No. 1-14607).
Four)).

This seal structure, as shown in FIG.
Slide the valve box seats 5A and 5B into contact with the seat rings 6 and 6.
Seat valve 6 and valve box seats 5A and 5B of the sluice valve mounted on valve box 1 in a state where they are prevented from coming off are fixed to valve box 1 movably in the direction of contact with and separation from sliding valve body 2. And a first spring 8 for urging the seat ring 6 in a direction of approaching the sliding valve body 2 in a state where the seat ring 6 is always in contact with the sliding valve body 2, A second spring 11 for urging the side valve box seat 5A in a direction approaching the sliding valve body 2 via a backup ring 10 is provided in the upstream seal box 7, and the outer periphery of the backup ring 10 and A seal member 16 made of a gland packing is provided between the seal box 7 and the seal box 7 whose outer circumferences face each other.

However, in the seal structure of the already filed application, gas penetrates the interposition portion of the second spring 11 along the path indicated by the arrow A and foreign matter such as coke accumulates, impairing the urging function of the second spring 11 to prevent the sealing performance. There is a risk of lowering.

In addition, the seal member 16 composed of a gland packing
Since it is interposed in a state where it cannot be retightened, it tends to cause deterioration in sealing performance due to stress relaxation over time.

If the sealing performance of the seal member 16 is deteriorated, there is a possibility that back leakage (leakage toward the bonnet side) of the path indicated by the arrow a may occur.

The present invention has been made in view of the above circumstances, and provides a good sealability even if the valve box seat is abraded with time, or even if there is a relatively large difference in load pressure on both sides of the sliding valve body. It is an object of the present invention to provide a seal structure for a sluice valve that can be ensured and can surely prevent gas from entering the back spring and back leakage.

[Means for Solving the Problems] In order to achieve the above object, the present invention is mounted in a state in which a pair of valve box seats slidingly contacting both surfaces of a sliding valve body are retained by a pair of seat rings. A seal structure for a sluice valve, wherein the pair of seat rings and the valve box seat are respectively attached to a pair of seal boxes so as to be movable in the contacting and separating directions with respect to the sliding valve body. A first spring for urging the ring in a direction in which the ring is always in contact with the sliding valve body is provided so that the upstream valve box seat is close to the sliding valve body via the backup ring. A second spring urged in the direction is provided in each of the seal boxes, and a seal portion extending between the back surface of each of the valve box seats and the backup ring on both inner and outer sides in the radial direction. The material is provided.

[Operation] According to the present invention, since the seat ring is lightly pressed against the sliding valve body by the first spring, foreign matter adhering to the surface of the sliding valve body is scratched as the sliding valve body slides. While dropping, even if the seat ring is worn by sliding contact with the sliding valve body, the seat ring slides in the direction close to the sliding valve body and is always kept in contact with the sliding valve body.

Further, the valve housings on both sides are pressed against the sliding valve body by the second spring, even if they are abraded with the passage of time, while the bending is prevented by the backup ring.

Further, even if the load pressure on both sides of the sliding valve body fluctuates and the sliding valve body is urged to the downstream side where the load pressure is small and moves a little, the sliding valve body is urged by the urging of the second spring. The sheet is pressed to ensure the sealing property.

The seal member provided between the back surface of each valve box seat and each backup ring can reliably prevent gas from entering and leaking back into the second spring interposition portion. Further, since each of the sealing members is provided with the extending side portion in the radial direction, it is possible to closely adhere to the inner side surface of the seal box through the extending side portion in a wide area, and the back leakage prevention action is provided. Can be reliably exerted, and the sealing function having this sealing member can be provided on both sides of the sliding valve body, and the sealing performance is further improved.

[Embodiment] An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a vertical sectional front view of a gate valve, and FIG. 2 is a half-cut sectional view showing an enlarged main part.
A sliding valve body 2 that is vertically movable between a raised valve opening position and a lowered valve closing position is provided therein.
The surface of the is coated with a coating (for example, LCIC coating of UCAR) for improving the sealing property, abrasion resistance, and seizure prevention, and the operating tool 4 that can be moved up and down through the valve rod 3 is used as a valve. Valve box seats 5A, 5B made of, for example, SC carbon, which are provided in the box 1 and are in sliding contact with the sliding valve body 2,
For example, the seat rings 6 and 6 made of nickel cast iron are attached to the pair of seal boxes 7 and 7, respectively, and the seal boxes 7 and 7 are attached to the valve box 1 and carbonized by pyrolysis. A sluice valve is provided in a passage for passing hydrogen gas and combustion exhaust gas.

The seat ring 6 is attached to the seal box 7 so as to be movable in the contacting and separating directions with respect to the sliding valve body 2, and slides in a state in which it is constantly in contact with the sliding valve body 2 regardless of the vertical movement of the sliding valve body 2. The coil spring-shaped first spring 8 urges the valve body 2 in a direction approaching the valve body 2, and as the sliding valve body 2 slides, the adhered matter such as coke attached to the surface of the sliding valve body 2 is removed.
The seat ring 6 is configured to be scraped off.

In addition, the valve box seat 5 that slides on both sides of the sliding valve body 2
Between the back of A and 5B and each backup ring 10, both
Extending side parts extending from 5A, 5B, 10 to both the inside and outside in the radial direction
A sealing member 9 having 9a and 9b, for example, a thin metal-containing graphoil gasket is provided.

As a result, the gas is prevented from entering the interposed portions of the second springs 11 on the path corresponding to the above-mentioned arrow A and the path opposite to this path. Therefore, foreign matter such as coke accumulates in the interposed portion of the second spring 11, the impelling function of the second spring 11 is impaired, and there is no inconvenience that the sealability is deteriorated.

Further, even if the use of the seal member 16 composed of the gland packing interposed in the state where the conventional tightening is not possible is omitted, the path indicated by the arrow a and the opposite side corresponding to the path a are omitted. It is possible to prevent back leakage from the route.

The seal box 7 is attached to the valve box 1 with mounting bolts 12
The retainer 14 is detachably fixed by a bolt 13 and an annular retainer 14 is detachably attached by a bolt 13. The valve box seats 5A, 5A, 5A, 5A are provided before the sliding valve body 2 is assembled or removed.
The B, seat ring 6, first spring 8 and second spring 11 are prevented from falling off.

In the above configuration, for the load pressure on the upstream side (right side), that is, for the positive pressure load, this fluid pressure and the second spring
By the cooperation of the spring force of 11, the sliding valve body 2 is urged to the downstream side (left side) and the sliding valve body 2 is pressed against one valve box seat 5B to increase the sealing surface pressure of this portion. To secure sealing performance, and the other valve box seat 5A is a backup ring.
By being pressed against the second spring 11 via 10 without bending, sealing performance is secured by the sealing surface pressure generated at this portion.

In addition, if the differential pressure between the load pressure (positive pressure) on the upstream side and the pressure (reverse pressure) on the downstream side is small, or if a small back pressure (negative pressure) occurs on the downstream side, the fluid on the upstream side Since it cannot be expected to urge the sliding valve body 2 to the downstream side by the pressure, in this case, the sliding valve body 2 is mainly urged to the downstream side by the spring force of the second spring 11, and the sliding valve The body 2 is pressed against the valve box seat 5B to increase the sealing surface pressure of this portion in the same manner as described above to ensure the sealing performance, and the valve housing seat 5A is pressed against the sliding valve body 2 to secure the sealing performance. To do.

Further, when the differential pressure between the positive pressure (right side) and the reverse pressure (left side) is relatively large, that is, the difference between the load pressures on both sides of the sliding valve body 2 becomes relatively large, the sliding valve body 2 Even if the second spring 11 is biased to the counter pressure load side and moves slightly to the counter pressure side, the second spring 11
The valve box seat 5B is brought into pressure contact with the sliding valve body 2 by the urging force to secure the sealing property.

Also, the back of the valve box seats 5A and 5B and the backup ring 1
Since the seal member 9 provided between 0 and 10 can surely prevent the above-mentioned invasion of gas into the interposing portion of the second spring 11 and back leakage, the urging function of the second spring 11 is provided. Is not impaired and the sealing performance is not deteriorated, and the extension side portion of the seal member 9 is
Since 9a and 9b can be sufficiently brought into close contact with the inner surface of the seal box 7, back leakage can be reliably prevented, and in particular, the sealing function having the seal member 9 is provided on both sides of the sliding valve body 2. Therefore, the sealing performance can be significantly improved.

On the other hand, the inspection and replacement of the valve box seats 5A, 5B and the seat ring 6 can be easily performed by removing the mounting bolt 12 and taking out the seal box 7 from the valve box 1.

In addition, in the above-mentioned embodiment, the sluice valve in which the sliding valve body 2 moves up and down is described, but it goes without saying that the present invention is also applicable to a lateral sluice valve in which the sliding valve body 2 moves horizontally. .

[Advantages of the Invention] As described above, according to the present invention, the sliding contact surface of the sliding valve body is always kept smooth by the scraping action of the seat ring, so that the valve box seat and the sliding valve body can be maintained. Since the backup valve prevents the valve box seat from being bent due to the sliding operation of the sliding valve body, the second spring presses the valve box seat against the sliding valve body. A uniform sealing state is obtained, and even if the valve box seat wears over time due to the sliding contact between the valve box seat and the sliding valve body, high sealing performance is maintained for a long time without lowering the sealing surface pressure. Can be secured.

In addition, since a seal member provided between each valve box seat and each backup ring prevents gas from entering the second spring interposition portion, foreign matter such as coke may enter the second spring interposition portion. It is possible to prevent the inconvenience that the accumulation function of the second spring is impaired and the sealing property is deteriorated. Moreover, since the extended side portion of the seal member can be brought into close contact with the inner side surface of the seal box over a wide area, the back leakage prevention effect can be surely exhibited, and in particular, the sealing function of the seal member slides. Since it is provided on both sides of the valve body, the seal function can be remarkably improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional front view showing an embodiment of the present invention, FIG. 2 is a half-cut sectional view showing an enlarged main part, and FIG. 3 is a half-cut sectional view of a conventional example. 1 …… Valve box 2 …… Sliding valve body 5A, 5B …… Valve box seat 6 …… Seat ring 7 …… Seal box 8 …… First spring 9 …… Seal member 10 …… Backup ring 11 …… No. 2 springs

Claims (1)

[Scope of utility model registration request] 1. A seal structure for a sluice valve, wherein a pair of valve box seats slidingly contacting both sides of a sliding valve body are attached in a state of being prevented from coming off by a pair of seat rings.
The pair of seat rings and the valve box seat are attached to the pair of seal boxes so as to be movable in the contacting and separating directions with respect to the sliding valve body, respectively, and the seat ring is slid in a state of being constantly in contact with the sliding valve body. A first spring is provided for urging the valve box in the direction close to the valve body, and a second spring is urged in the direction in which the upstream side valve box seat approaches the sliding valve body via a backup ring on both seal boxes. A seal structure for a sluice valve, characterized in that a seal member is provided between each of the back surfaces of the respective valve box seats and the backup ring and extends radially inward and outward from both of them.