JPH03149471A - Check valve - Google Patents

Abstract

PURPOSE:To reduce oscillation of a valve body and to prevent abrasion on a contact surface by welding an antifrictional hard material to the contact, to which an arm supported in a channel so as to rotate freely and the valve body that can oscillate are fitted, and by forming it in a curvature surface. CONSTITUTION:In a check valve which is seated on a valve seat 2 at the time of reverse running of a fluid, so as to prevent the reverse running, one end of an arm 4 is supported in a valve box so as to rotate freely, while a valve body 3 that is fitted to the other end, and is fastened by nut, is formed so as to allow oscillation. An antifrictional hard material 14 is welded to a contact 12, to which the arm 4 and the valve body 3 are fitted, while a curvature surface or a tilting surface is formed. The valve body 3 can thus be in a surface contact at a maximum oscillating angle of oscillation to the arm 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a check valve used in piping systems such as nuclear power plants.

(Prior technology) Check valves used in each system within a nuclear power plant are installed to prevent backflow of fluid in piping, and if backflow occurs due to pressure fluctuations in the internal fluid, etc., the check valves are The valve must also close reliably.

As shown in FIG. 5, this type of conventional check valve has a valve body 3 attached to a rotatable arm 4 such that it is seated on a valve seat 2 in a valve box 1 so that backflow of fluid occurs. It consists of things. On the right, numeral 5 is a fluid inlet, 6 is an outlet, 7 is a valve lid, 8 is a rotation support bottle, and 9 is a stopper. The valve body 3 is fitted into the arm 4, and is fixed by being tightened with a nut 11 with a washer 10 interposed therebetween.

Such conventional check valves have internal fluid pressure and valve body 3.
The valve body 3 closes due to its own weight, but in order to ensure that the valve body 3 is seated on the valve seat 2 and to prevent the valve seat 2 from leaking due to back pressure, the valve body 3 and the arm 4 are connected as shown in FIG. Fitting part 12
A slight gap a is provided in the valve body 3, and an inclined surface is formed on the fitting portion 12 on the arm 4 side, thereby making it possible to swing the valve body 3 into close contact with the valve seat 2.

The inclination angle d of this inclined surface 13 has twice the maximum deflection angle s.

(Problem to be Solved by the Invention) However, in such a conventional check valve, the swinging motion or rotational motion of the valve body 3 constantly occurs during operation depending on the flow velocity or flow condition of the internal fluid. There are factors that can adversely affect the function and integrity of the check valve due to wear of the fitting part, and may impede the steady operation of the nuclear power plant. That is, as shown in FIG. 6, since the fitting portion 12 of the arm 4 is formed with an inclination angle d from one end to the other, the arm 4 and the valve body 3 are in line contact, which prevents fluctuations in the internal fluid. There is a problem that the system becomes unstable and its soundness is impaired.

The present invention has been made to solve the above problems, and ensures the operation of the valve body by preventing the occurrence of wear on the fitting portion between the valve body and the arm due to the oscillation or rotational movement of the valve body. The object of the present invention is to provide a check valve that can ensure the integrity of the check valve and sufficiently fulfill the functions of each system piping of a nuclear power plant.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a valve box in which a valve seat is provided in a flow path leading from a fluid inlet to an outlet, and one end of which is rotatable within the valve box. In the check valve, the valve body is formed to be able to swing relative to the arm so as to be fitted to the other end of the arm and fixed by tightening a nut, A wear-resistant hard material is welded to the fitting contact portion between the arm and the valve body, and a curved surface or an inclined surface is formed so that the valve body can move at the maximum swing angle of the swing motion with respect to the arm. A special feature characterized in that the valve is in surface contact with the arm) The fluid flows from the inlet to the outlet through the flow path, and a reverse flow occurs, causing the valve body to oscillate depending on the flow rate and flow condition of the internal fluid. When motion or rotational motion occurs, its magnitude is minute and gentle. In addition, the occurrence of wear at the fitting portion is prevented by reducing the contact surface pressure due to an increase in the diameter of the fitting portion and by increasing the hardness of the contact surface due to welding of hard materials.

(Example) An example of a check valve according to the present invention will be described with reference to FIGS. 1 and 2.

Components in FIG. 1 that are the same as those in FIG. 5 are designated by the same reference numerals, and explanations of overlapping portions will be omitted. In addition, in FIG. 1, only essential parts of the present invention are shown.

In FIG. 1, the arm 4 is fitted with the valve body 3, and the washer 10 and nut 11 are used to tighten the valve body 3.
is supported by arm 4. As shown in FIG. 2, there is a gap a between the arm 4 and the valve body 3.
When seated on the valve seat 2, the structure is such that the angular deviation between the valve seat 2 surface and the valve body 3 surface is absorbed and they come into close contact.

Therefore, when the check valve in the above embodiment is in the open state as shown in FIG.
Therefore, an inclination b is generated with respect to the center line of the fitting hole 15 of the arm 4. That is, the inclined surface 16a of the contact portion 16 separated by the dotted line A and the dotted line B in FIG. 2 forms a straight line in the cross-sectional state of FIG. There is. . Thereby, the arm 4 and the valve body 3 have a structure in which they are in surface contact.

Further, the inclined surface 16b of the contact portion 16 separated by the dotted line B and the dotted line C is formed into a curved surface. Further, by bringing the wear-resistant hard material 14 into close contact with the contact surface, the surface hardness is increased, and the diameter of the fitting portion 12 of the valve body 3 is increased to reduce the contact surface pressure.

The wear-resistant hard material 14 may be formed by welding stellite or the like, or by thermally spraying a wear-resistant metal or ceramic material.

Therefore, according to this embodiment, the oscillation and rotation phenomena of the valve body 3 are significantly reduced, and furthermore, the occurrence of wear on the contact surface is prevented due to the reduction in surface pressure and increase in hardness of the contact surface, and the occurrence of wear on the contact surface is prevented. The soundness of the surface can be ensured.

Figures 3 and 4 respectively show only the main parts of other embodiments of the present invention. In FIG. 3, the contact portion 17 of the arm 4 at the fitting hole 15 is formed into a curved surface 17a, and is formed so that the contact line between the arm 4 and the valve body 3 changes during swinging motion. . Figure 4 shows arm 4 and valve body 3.
The arm 4 has a curved surface 17 at its contact surface on the side of the gap a. Further, the fitting hole 15 of the arm 4 is connected to the valve seal 3.
It has an inclined surface 16 that matches the inclination of.

Note that the other structure is the same as that of the embodiment shown in FIG. That is, the check valve in each of the above embodiments includes a valve box 1 having a valve seat 2 in a flow path leading from an inlet 5 to an outlet 6.
The outflow port 5 contacts the valve seat 2 to prevent backflow of fluid.
When fluid pressure is applied from the side, the valve element 3 opens in the direction away from the valve seat 2 to allow fluid to flow, and the valve body 3 has a hard material 14 welded to the fitting contact portion with the arm 4. A hard material 14 is rotatably supported and welded to the contact surface of the fitting portion 12 with the valve body 3, so that the contact surface of the fitting portion 12 ensures contact between the valve seat 2 and the valve body 3. The present invention is characterized in that it includes an arm having a curved surface 17 or an inclined surface 16. This prevents wear on the contact surface between the arm 4 and the valve body 3, which is thought to be a cause of malfunctions in conventional check valves, and ensures its integrity. This has an excellent effect of improving reliability.

[Effects of the Invention] According to the present invention, the swinging and rotation phenomena of the valve body are significantly reduced, and the occurrence of wear on the contact surface is prevented by reducing the contact pressure and increasing the hardness of the contact surface, thus improving the integrity of the valve body. Moth (
A secured check valve can be provided.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view showing essential parts of an embodiment of the check valve according to the present invention, FIG. 2 is a schematic diagram for explaining the relationship between the arm and the valve body in FIG. 1, and FIG. 3 and FIG. 4 is a side view showing only the main part of another embodiment of the present invention in partial cross section,
Figure 5 is a vertical sectional view partially showing a conventional check valve from the side;
This figure is a schematic diagram for explaining the relationship between the arm and the valve body in FIG. 5. 1-- Valve box 2... Valve seat 3... Valve body 4... Arm 5-... Inlet 6... Outlet a... Lid 8
...Support bottle 9...Stopper ■...Washer 11...Nut 12...Fitting part...
Slanted surface 1, hard material, fitting hole
lG, 17...Contact part 1F...Curved surface agent Patent attorney Nori Chika Ken Yudo Deshimaru Takehachi 16b Fig. 2 1 rゝ11 Fig. 3 1111JI- Fig. 4 a-Xr1-4 No. 6 figure

Claims (1)

[Claims] A valve box in which a valve seat is provided in a flow path leading from a fluid inlet to an outflow port, an arm whose one end is rotatably supported within the valve box, and which is fitted into the other end of the arm. A check valve comprising a valve body that is fixed by tightening a nut and seats on the valve seat to prevent backflow when fluid flows backward, and a wear-resistant hard material is used at the fitting contact portion between the arm and the valve body. What is claimed is: 1. A check valve characterized in that a check valve is welded to a curved surface or an inclined surface.