JPS6333019Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sealing valve that can completely block fluid flow when the valve is closed.

[Conventional technology]

When a flow control valve such as a globe valve is provided with a fluid sealing function, the seat surface of the valve seat is made of a material such as rubber or Teflon, and the sealing portion of the valve body is brought into close contact with this seat surface to seal the fluid as a primary source. It is common to prevent leakage from the side to the secondary side.

[Problem that the invention attempts to solve]

However, if the rubber or Teflon part becomes deformed due to aging or melts due to heat, a gap will form between the seat surface of the valve seat and the sealing part of the valve body, and the sealing function will be lost. The problem is that you get used to it. In particular, in recent years, such sealing valves have been increasingly used to control the flow of flammable fluids such as LPG and LNG, so the risk of the Teflon parts melting due to a fire has increased accordingly. Therefore, some kind of countermeasure is desired.

Such a deterioration phenomenon is recognized as a problem that cannot be solved by a sealing valve having a structure in which the same type of tight seal is also provided.

The present invention attempts to overcome the above-mentioned problems by employing a different type of double seal structure consisting of a contact seal and a non-contact seal.

[Means for solving problems]

In order to achieve such an object, the present invention provides a valve seat including a sub-seat surface formed in an annular groove around the outer periphery of a main seat surface formed on a tapered surface, and a sub-seat surface that is in close contact with the main seat surface. The present invention provides a sealing valve having a structure including a valve body provided with an annular protrusion having a cross-sectional shape corresponding to the annular groove on the outer periphery of the packing and closely fitting into the sub-seat surface.

[Effect]

In the sealing valve of the present invention, the packing comes into close contact with the inner main seat surface to create a tight seal, and the annular protrusion fits into the outer sub-seat surface (annular groove) to create a labyrinth seal. Therefore, even if the packing deteriorates due to factors such as aging and leakage occurs in the tight seal, the labyrinth seal portion, which is not affected by such deterioration factors, guarantees the seal.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

A valve seat 2 and a valve body 3 are arranged within a valve box 1. Further, the valve shaft 4 connected to the valve body 3 is connected to the valve body 1.
It is made to extend to the outside through the shaft sealing part 1a. Then, the valve shaft 4 is driven by an actuator (not shown) or the like disposed outside the valve box 1, and the valve body 3 is
By moving back and forth in the axial direction, it is possible to adjust the amount of fluid flowing from the primary flow path 1b to the secondary flow path 1c, or to block the flow.

The valve seat 2 is a ring-shaped member that is screwed into the communication hole 1d that communicates the flow paths 1b and 1c, and has a main seat surface 5 formed into a wide tapered surface on the inner peripheral edge of the upper surface. At the same time, a sub-seat surface 6 formed in an annular groove having a U-shaped cross section is recessed in an outer peripheral portion surrounding the main seat surface 5 on the upper surface.

On the other hand, the valve seat 2 has a funnel-shaped valve body 7 that is loosely fitted into the communication hole 1d and forms an annular flow rate control space between the valve seat 2 and the valve seat 2. And this valve body 7
A small diameter portion 7a and a threaded portion 7b having a smaller diameter than the small diameter portion 7a are provided at the upper end, and a packing 8 forming a main seal portion is wound around the small diameter portion 7a, and the packing 8 is wrapped around the male threaded portion 7b. A flange 9 is screwed on to fix it. The packing 8 is a ring-shaped material made of rubber or Teflon, and is attached to the main seat surface 5 of the valve seat 2.
It has a tapered sealing surface 8a that comes into close contact with. On the other hand, the flange 9 is nut-shaped, and an annular protrusion 1 forming a sub-seal part is formed on the outer peripheral edge of the lower surface of the flange 9.
1 is provided protruding downward. The annular protrusion 11 has a cross-sectional shape corresponding to the sub-seat surface 6, and when the valve body 3 is moved to a position where the packing 8 comes into close contact with the main seat surface 5, the annular protrusion 11 has a cross-sectional shape corresponding to the sub-seat surface 6. It is designed to fit closely into the sub-sheet surface 6. The flange 9 is fixed to the valve body 7 by caulking the upper end of the male threaded portion 7b.

With such a device, the flow rate of the fluid flowing from the primary flow path 1b to the secondary flow path 1c can be adjusted by moving the valve body 3 up and down, and the valve body 3 can be moved up and down. By moving the body 3 to the lowest end and bringing the packing 8 into close contact with the main seat surface 5 of the valve seat 2, the outflow of fluid from the primary flow path 1b to the secondary flow path 1c is blocked. be able to. In this case, the annular protrusion 11 provided on the outer periphery of the packing 8 also fits into the sub-seat surface 6 formed in the annular groove on the outer circumferential surface of the main sheet surface 5, so that the packing 8 deforms due to aging. Even if the fluid melts due to heat caused by a fire or the like, leakage of fluid from the primary flow path 1b to the secondary flow path 1c can be prevented.

According to this seal structure, it is not just that a double sealing effect is obtained on the main and sub inner and outer seat surfaces 5 and 6, but that a separate sealing mechanism is provided on both sides. It has characteristics. In other words, the outer annular groove (sub-seat surface 6) exhibits a labyrinth seal function through uneven fitting, which has a different sealing mechanism from the packing seal on the inner main sheet surface 5. Even if leakage occurs on the surface 5 due to deterioration of the packing 8, the sub-sheet surface 6 is not affected by such leakage factors, and leakage is reliably prevented at that portion.

Furthermore, with the double seal having such a structure, a large seating force (surface pressure) is obtained on the annular protrusion 11 fitted into the outer annular groove, while a large seating force (surface pressure) is obtained on the main sheet surface 5 forming the tapered surface. Since excessive surface pressure is not applied to the packing 8 in close contact with the annular protrusion 11 as a stopper, deterioration of the packing 8 is also reduced.

Note that the annular protrusion 11 is not limited to the one in the embodiment described above, but may be, for example, a protrusion 11' having a triangular cross section as shown in FIG. 3, or a protrusion 11'' having a rectangular cross section as shown in FIG. Various modifications are possible, such as.Furthermore, the position where it is formed is not limited to the outer peripheral edge of the flange.For example, it may be formed at a position as shown in FIGS. 4 and 5.

[Effect of idea]

This invention adopts the different types of double seal structure as described above, so that the sealing function between the main sheet surface and the packing is prevented due to deformation due to aging of rubber or Teflon packing or melting due to fire. Even if it were to be damaged, the fluid sealing function can be maintained by the labyrinth seal created by the sub-sheet surface and the annular protrusion provided around the outer periphery.

Further, the annular protrusion serves as a stopper to protect packing. Therefore, the sealing valve of the present invention can maintain the sealing effect even under conditions where deterioration of the packing has conventionally caused unexpected leakage accidents.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an embodiment of the present invention, and FIG. 2 is a partially cutaway front view showing an exploded main part of the embodiment. FIGS. 3, 4, and 5 are partial cross-sectional views showing other embodiments of the present invention. 2... Valve seat, 3... Valve body, 5... Main seat surface, 6... Sub seat surface (annular groove), 8... Packing, 11, 11', 11''... Annular protrusion.

Claims (1)

[Scope of utility model registration request] A valve seat is provided with a sub-seat surface formed in an annular groove on the outer periphery of a main seat surface formed on a tapered surface, and a packing that is in close contact with the main seat surface has a cross-sectional shape corresponding to the annular groove on the outer periphery thereof. and a valve body having an annular protrusion that is closely fitted into the sub-seat surface.