JPH09170667A - Plug valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce erosion by smoothening fluid flow, conduct disassembling without damaging any sound part when partial repairing is required, and conduct prescribed repairing easily, promptly and at a lower cost at a site where a valve is installed. SOLUTION: A plug 2 which is mounted on the end of a stem tube 1 and let to go into/out of the cone-shaped seat part of a fluid tude is constituted into a separating type of its top end part 2A and a base end part 2B. The plug base end part 2B is welded (10) to the outer periphery of the top end of the stem tube 1 at its top end. The plug base end part 2B and the plug top end part 2A are welded (11) to each other at their peripheries, and the top end of a straight tube type protector 3 is integrated with the plug base end part 2B by welding.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plug valve, and more particularly to a valve used mainly for controlling the flow rate and pressure of a high temperature catalyst. The plug is attached to the tip of the stem tube and is fitted to the outside of the stem tube. A plug valve capable of adjusting the flow rate in the fluid pipe by allowing the plug to move in and out of the cone-shaped seat portion at the tip of the fluid pipe by linearly moving integrally with the protected protector along the axial direction of the stem tube It is a thing.

[0002]

2. Description of the Related Art FIG. 4 is a cross-sectional structure of an essential part showing a plug valve which has been generally used in the past in a closed state.
As is apparent from the figure, the plug 2 is concentrically fitted and held at the base end portion thereof to the tip of the stem tube 1 in which the vapor flow path 1A is formed, and at the outside of the tip portion of the stem tube 1. The tip portion 3a of the protector 3 fitted to the above is formed into a tapered cone shape, and the protector tip portion 3a having the tapered cone shape and the base end portion of the plug 2 are welded to the outer circumference of the distal end of the stem tube 1. Plug 2, protector 3 and stem tube 1 are integrated, and the integrated plug 2, protector 3 and stem tube 1 are connected to the base end of the stem tube 1 by a hydraulic cylinder (not shown). The plug 2 is linearly moved in the axial direction X via the plug 2 to move the plug 2 into and out of the cone-shaped seat portion 5 formed at the tip of the fluid pipe 4.
A flow rate and a pressure of an external fluid b such as a high temperature catalyst which is sucked into the fluid pipe 4 through the cone-shaped seat portion 5 in accordance with an ejector action of the vapor a ejected from A into the fluid pipe 4 are configured to be adjustable. ing.

The flow rate associated with the linear movement of the plug 2
As a measure against erosion in a portion that is likely to be damaged by a local impact force due to the pressure-adjusted external fluid b, a heap portion 7 is provided on the tip of the plug 2 and the outer peripheral surface of the plug 2 and the protector 3 are provided. Castable linings 8 and 9 are installed on the entire outer peripheral surface.

[0004]

In the conventional plug valve having the above-mentioned structure, the metal deposit 7 at the tip of the plug 2 is used.
Although the erosion is reduced by applying the castable linings 8 and 9, if the external fluid is a highly corrosive fluid such as a catalyst, erosion is promoted as the material corrodes, and Even if erosion countermeasures are taken, it is necessary to partially repair the construction parts of the above-mentioned metal deposit part 7 and castable linings 8 and 9. In particular, local recesses are formed at six points of welding between the base end of the plug 2 and the tip of the tapered cone-shaped protector 3a, and the flow of the external fluid changes rapidly there. The parts of are susceptible to erosion and require short-term repair.

At the time of such repair, in the conventional plug valve having the above-mentioned structure, the plug 2, the stem tube 1, and the protector 3 are integrated by welding 6 on the outer periphery of the distal end of the stem tube 1. This is a troublesome and time-consuming work such as removing from the pipe for installing the plug valve, releasing the welding 6 to separate them, and repairing the necessary parts. It was difficult or impossible. Also,
When repairing, it was necessary to partially reconstruct even the healthy part, and there were many cost losses.

Therefore, the present invention has been made in view of the above circumstances, and not only can the fluid flow be smoothed to reduce erosion, but also partial repair can be performed easily and quickly at the valve installation site, and The purpose is to provide a plug valve that can be implemented cost-effectively.

[0007]

To achieve the above object, a plug valve according to the present invention comprises a plug attached to the tip of a stem tube and a protector fitted to the outside of the stem tube. In the plug valve in which the plug is moved in and out of the cone-shaped seat portion at the tip of the fluid pipe by linearly moving integrally along the axial direction of the tube to adjust the flow rate in the fluid pipe, the tip portion of the plug is The base end portion is configured as a separate type, of which the plug base end portion is welded at its tip to the outer circumference of the stem tube tip, and the plug base end portion and the plug tip end portion are mutually connected at their outer circumferences. It is characterized in that the protector is welded to form a straight tube, and the tip of the protector is integrated with the base end of the plug by welding. By this is welded directly to the plug proximal end, eliminating abrupt change of the flow of the external fluid in the vicinity of the base end portion of the plug, it is possible to reduce the occurrence of erosion. In addition, if erosion occurs at the tip of the plug and partial repair is required, the outer peripheral weld between the plug tip and the base end should be released to remove and repair only the plug tip. It is possible to replace the plug and protector, and if erosion occurs in other parts of the plug or the protector and it is necessary to repair those parts, replace the plug and protector with other healthy parts such as the stem tube. It is possible to easily perform a predetermined repair by removing the parts integrally without damaging the parts.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional front view of a main part showing a plug valve according to the present invention in its closed state, and FIG. 2 is an enlarged view of the main part. In FIG. 1, 1 to 5, 1A are conventional ones shown in FIG. Since the components are the same as those in the example, the same reference numerals are given to the corresponding portions, and detailed description thereof will be omitted.

The plug 2 is constructed as a separable type of the tip portion 2A and the base end portion 2B, of which a tip portion 2A of the plug tip portion 2A and a wall portion 7 for erosion countermeasures are provided on the peripheral wall surface. And the plug base end 2B
A castable lining 8 for erosion countermeasures is applied to the outer peripheral wall surface and the base end surface of the. The base end portion 2B of the plug is circumferentially welded 10 to the outer periphery of the distal end of the stem tube 1 at its distal end, and the base end portion 2B of the plug and the distal end portion 2A of the plug are circumferentially welded to each other at their outer periphery. Has been done.

The protector 3 concentrically fitted to the outer circumference of the stem tube 1 is formed in a straight tube shape, and a castable lining 9 for erosion countermeasures is provided on the outer peripheral surface thereof, and the tip of the straight tube protector 3 is provided. The portion is integrated by circumferentially welding 12 to the base end surface of the plug base end portion 2B by penetrating the castable lining 8 formed on the base end surface of the plug base end portion 2B.

In the plug valve having the above-mentioned structure, normally, the plug 2 (2A, 2B), the protector 3 and the stem tube 1 are integrated, and these integrated parts are connected to the base end portion of the stem tube 1 by a hydraulic pressure. By moving the plug 2 in and out of the cone-shaped seat portion 5 formed at the tip of the fluid pipe 4 by linearly moving in the axial direction X through a cylinder (not shown), the inside of the fluid pipe 4 from the flow passage 1A. The flow rate and pressure of the external fluid b such as a high-temperature catalyst that is sucked into the fluid pipe 4 through the cone-shaped seat portion 5 in accordance with the ejector action of the vapor a injected to the are adjusted and used.

In such a normal state, the use of the straight tubular protector 3 does not cause a rapid change in the flow of the external fluid b in the vicinity of the base end portion of the plug 2 and is a smooth flow, so that the occurrence of erosion is extremely high. Few. When erosion occurs in the tip portion of the plug 2 due to long-term use or the like and partial repair is required, circumferential welding 11 between the plug tip portion 2A and the base end portion 2B and the tip of the plug base end portion 2B are performed. By releasing the circumferential welding 10 between the outer periphery of the stem tube 1 and the outer periphery of the stem tube 1, as shown in FIG. 3, only the plug distal end portion 2A is removed, and further, the plug proximal end portion 2B and the protector 3 are connected to the stem tube 1. By removing from the plug tip 2A, repair of the metal deposit 7 of the plug tip 2A, replacement of the plug tip 2A, or the plug base 2
It is possible to easily and quickly repair the castable linings 8 and 9 on the outer periphery of B and the protector 3 with the minimum necessary number of steps, and damage other healthy parts such as the stem tube 1 during the repair. Nor.

[0013]

As described above, according to the present invention, since the straight tubular protector is used and is directly welded to the base end portion of the plug, the flow of the external fluid near the base end portion of the plug. Can be kept smooth without sudden changes, and the occurrence of erosion can be reduced. Furthermore, when erosion occurs locally in the tip portion of the plug, by releasing the outer peripheral welded portion between the plug distal end portion and the base end portion and the outer peripheral welded portion between the plug base end portion and the stem tube front end, Since it is possible to remove only the plug tip, or remove the plug base and protector from the stem tube,
Replacement and repair of the plug tip can be performed easily and quickly even at the valve installation site without damaging other healthy parts such as the stem tube.
It is possible to perform a predetermined partial repair at low cost without the need to reconstruct a sound part.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional front view of essential parts showing a plug valve according to the present invention in a closed state.

FIG. 2 is an enlarged vertical cross-sectional front view of a main part of the above plug valve.

FIG. 3 is an enlarged vertical sectional front view showing an exploded state of the same plug valve at the time of repair.

FIG. 4 is a vertical cross-sectional front view of essential parts showing a conventional plug valve in a closed state.

[Explanation of symbols]

 1 Stem tube 2 Plug 2A Plug tip part 2B Plug base end part 3 Straight tubular protector 4 Fluid pipe 5 Cone sheet part 10, 11, 12 Welded part

Claims (1)

[Claims] 1. A plug attached to the tip of a stem tube and a protector fitted to the outside of the stem tube are linearly moved integrally along the axial direction of the stem tube to thereby move the plug into a fluid pipe. In a plug valve capable of adjusting the flow rate in the fluid pipe by moving in and out of a cone-shaped seat portion at the tip, the tip portion of the plug is configured as a separate type from the base end portion, of which the plug base end portion is While welding at the tip to the outer circumference of the stem tube tip, the plug base end portion and the plug tip end portion are welded to each other at the outer circumference thereof, and the protector is formed into a straight tube, and the tip end thereof is attached to the plug base end portion. A plug valve characterized by being welded and integrated.