JP2000199728A - Watertightness test method for valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily confirm leakage of a valve-stem penetration part in a valve device, in which a valve stem is passed through a valve cage. SOLUTION: A ventilation hole 12, through which a space inside a packing box 7 communicates with the outside, is formed in advance. A plug stopper 13 is installed at the opening part of the ventilation hole 12 so as to be freely detachable. In a watertightness test, test water is circulated inside a valve cage. While air at the inside of the valve cage is being discharged through the ventilation hole 12, the water is filled full. In the completely filled state in which a seal material part is immersed, the ventilation hole 12 is closed by using the plug stopper 13, the test water is pressurized, and the watertightness of a valve device is determined.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for testing water tightness of a valve device.

[0002]

2. Description of the Related Art In a gate valve shown in FIGS. 5 and 6, for example, a valve stem 3 is inserted into a canopy portion of a valve case lid 2 mounted on a valve case 1, and the valve stem 3 moves back and forth in the axial direction. The valve body 4 for opening and closing the valve port is disposed inside the valve box cover 2. Valve stem 3
The flange 3a is received by the valve box cover 2 by the thrust collar 5, and the shaft seal ring 6 is located on the tip side from the flange 3a.
And a packing box 7 is arranged so as to cover the shaft seal ring 6. O-rings 8 for stopping water between the valve stem 3 and the packing box 7 are disposed on the inner and outer peripheral sides of the shaft seal ring 6. The packing box 7 is fixed to the valve box lid 2 with fixing bolts 10 with a gasket 9 interposed at the flange portion 7a.

[0003]

However, in a valve device in which the valve stem penetrates through the valve box as in the above-described gate valve, the normal vertical posture (as shown in FIGS. 5 and 6, the valve stem is It is not easy to confirm the leakage of the valve stem penetration part in the position facing the direction). In other words, even if an attempt is made to fill the valve box with pressurized test water in order to confirm the presence or absence of leakage, the pressurized test water does not reach a sealing material site such as an O-ring due to air accumulated in the upper portion of the valve box. There is a possibility that confirmation of the sealing property at that location may be insufficient.

An object of the present invention is to solve the above-mentioned problem, and it is an object of the present invention to ensure that leakage of a valve stem penetration portion can be reliably confirmed even in a valve device in a vertical posture.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides a valve stem which is inserted into a through hole formed in a canopy portion of a valve box lid mounted on a valve box, and the valve stem is provided outside the through hole. In a valve device in which a sealing member for holding a sealing material for stopping water between the valve rod and the holding member is fitted to the valve rod, a holding member surrounding the periphery of the valve member is arranged. In addition to the provision of a ventilation hole that communicates with the outside in advance, a plug body is detachably provided at the opening of the ventilation hole, and at the time of a watertightness test, test water is passed through the valve box to allow air in the valve box to pass through the ventilation hole. The drain hole is filled with water while the sealing member is immersed, and the vent hole is closed by the plug and the test water is pressurized to determine the water tightness.

[0006] With the above configuration, even in the case of a valve device in a vertical position, it is possible to surely check the leakage of the valve stem penetrating portion.

[0007]

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

The soft seal gate valve shown in FIG. 1 has substantially the same configuration as the conventional gate valve described above with reference to FIGS. Valve box cover 2 constituting the canopy of valve box 1
Is arranged so as to cover the opening of the valve body storage portion of the valve box. Inside the valve box cover 2, a valve body 4 that is moved back and forth in the axial direction by a valve rod 3 to open and close a valve port is provided. Have been placed. The valve body 4 is provided with a synthetic rubber lining.

A through hole 2a through which the valve rod 3 is inserted is formed in the valve box lid 2. A flange 3a of the valve rod 3 is provided through a thrust collar 5 at a seat at a peripheral portion of the through hole 2a. Is receiving. A shaft seal ring 6 is fitted on the distal end side of the flange portion 3a of the valve stem 3, and a packing box 7 is arranged so as to cover the shaft seal ring 6.

The shaft seal ring 6 has annular grooves 6a and 6b on the inner and outer peripheral surfaces, and the valve stem 3 is provided in each of the annular grooves 6a and 6b.
O-ring 8 for stopping water between the packing and packing box 7
Has been arranged. The packing box 7 is fixed to the valve box lid 1 with fixing bolts 10 with a gasket 9 interposed at the flange portion 7a.

An operation cap 11 is attached to the tip of the valve stem 3, and a ventilation hole 1 communicating the space inside the valve box to the outside.
2 are formed. The vent hole 12 is provided in the flange 3 of the valve stem 3.
a lateral hole 12a in the radial direction of the flange portion, one end of which is open on the outer peripheral surface of
And a vertical hole 12b in the axial direction of the valve stem, which communicates with the horizontal hole 12a at one end and the other end is opened at the distal end surface of the valve stem 3, and the vertical hole 12b has a thread cut therearound. A plug plug 13 to be screwed is provided.

A method for testing the watertightness of the above-described soft seal gate valve will be described.

As shown in FIG. 2, one connection port of the valve box 1 of the gate valve in the vertical position is closed, and the other connection port is connected to the short pipe 15, the hydraulic jig 16 and the pump via the dockler 14. The device 17 is connected. In the gate valve, the operation cap 11 and the plug stopper 13 are removed to allow the inside of the packing box 7 to communicate with the outside via the ventilation hole 12.

Then, the gate valve is set to a fully closed state, and the pump device 17 allows the test water to flow into the valve box 1 through the hydraulic jig 16 and the short pipe 15. When the test water reaches a full state in which the test water flows out through the vent hole 12, the plug hole 13 is attached, the vent hole 12 is closed, a water pressure of 0.75 MPa is applied, and the pressure is maintained for 30 seconds. However, the tightening torque at this time is the maximum function test torque, and the water pressure is a predetermined pressure according to the nominal diameter of the gate valve. Then, the presence or absence of leakage is confirmed.

By doing so, the air inside the valve box is completely exhausted through the vent hole 12 and the inside of the valve box becomes full and the shaft seal ring 6 is completely immersed in the test water. That is, it is possible to easily and reliably confirm the water tightness at the shaft seal ring 6 and the water tightness between the packing box 7 and the valve box cover 1. In addition, since the vent hole 12 is formed in the valve stem 3, high quality rust prevention treatment by powder coating on the inside and outside of the valve, which is one of the features of the soft seal gate valve, is not hindered.

However, as shown in FIG. 3, even if the ventilation hole 12 penetrating the packing box 7 below the shaft seal ring 6 is formed, the watertightness of the valve stem penetration portion can be easily and reliably confirmed in the same manner. it can.

However, in order to prevent paint on the screw surface, it is necessary to perform screw processing after valve powder coating, and at this time, the coating on the screw surface and its surroundings is removed, and the rust prevention function is reduced. As a countermeasure, a screw bush 1 made of a corrosion-resistant material such as stainless steel as shown in FIG.
2a is attached by welding or the like, and the vicinity of the weld is repainted.

The above-described water tightness test method can be applied to all valve devices in which a valve stem penetrates a valve box, in addition to a soft seal gate valve.

[0019]

As described above, according to the present invention, in a valve device in which a valve stem penetrates a valve box, a vent hole for communicating a space inside the valve box to the outside is provided in a valve box lid or a valve stem in advance. With this configuration, the inside of the valve box of the valve device in the vertical position can be completely evacuated and filled with water, and the water tightness of the valve stem penetration can be easily and reliably confirmed.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a main configuration of a valve device suitable for performing a water tightness test method of the present invention.

FIG. 2 is an explanatory diagram showing an arrangement of valve devices and the like when the water tightness test method is performed.

FIG. 3 is an explanatory diagram showing a main configuration of another valve device suitable for performing the water tightness test method of the present invention.

4 is a partially enlarged view of the valve device shown in FIG.

FIG. 5 is a partially cutaway perspective view showing the entire configuration of a conventional gate valve.

FIG. 6 is a longitudinal sectional view showing an upper configuration of the gate valve.

[Explanation of symbols]

 2 Valve box cover 2a Through hole 3 Valve rod 6 Shaft seal ring (seal holding material) 7 Packing box (holding member) 8 O-ring 12 Vent hole 13 Plug plug

Claims (1)

[Claims] Claims: 1. A valve rod is inserted into a through hole formed in a canopy portion of a valve box lid mounted on a valve box, and a holding member surrounding the periphery of the valve rod is arranged outside the through hole. In a valve device in which a seal holding member that holds a seal member for stopping water between the holding member and the holding member is fitted to a valve stem, a vent hole that communicates a space inside the holding member with the outside is provided in advance, and A plug is detachably provided in the opening, and at the time of a watertightness test, the test water is passed through the valve box and the air in the valve box is exhausted through the vent hole and filled with water. A method for testing the water tightness of a valve device, wherein the watertightness is determined by closing a vent hole with a plug and pressurizing test water.