JPS5941064B2 - lift type check valve - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement in a lift type check valve.

A conventional screw-tight lift type check valve will be explained with reference to FIG.

When fluid flows from the inlet 1 direction to the outlet 2 direction, the valve body 3
floats up from the valve seat 4 and is guided by the valve stem 5 and rises to allow fluid to pass through.

In this way, when the fluid flows from the forward direction, the fluid is allowed to flow, but when the fluid flows from the outlet 2 to the inlet 1 in the opposite direction, the valve body 3 comes into close contact with the valve seat 4 and blocks the flow.

When attempting to block both forward and reverse flow, the valve stem 5 is lowered and the valve body 3 is pressed against the valve seat 4, but normally the valve stem 5 is pulled up to its upper limit position.

When the flow in the forward direction is sufficiently large, the valve body 3 rises from the valve seat 4 and remains stationary. However, when the flow rate decreases, the force pushing up the valve body 3 is insufficient, causing damage to the system and check valve. Under certain conditions determined from the specifications, the valve body 3 vibrates.

In conventional check valves, when this vibration phenomenon occurs, the valve body 3, valve seat 4, and valve stem 5 collide, resulting in damage to the collision surfaces when used for a long time under vibration conditions.

Check valves are selected taking into consideration the vibration phenomenon described above, but when the flow rate fluctuation range is wide, the disadvantage is that it is impossible to prevent vibration of the valve body at low flow rates and damage to the valve body etc. there were.

An object of the present invention is to provide a lift type check valve that prevents the valve body from colliding with the valve stem and valve seat and being damaged due to valve body vibration.

In the present invention, the valve body is formed into a cylindrical shape having an internal cavity, and a piston fixed to the lower end of the valve stem is slidably fitted into this cavity, so that when the valve body slides, the fluid inside the valve body is buffered. A fluid passage is provided in the valve body so that it acts as a material.

Hereinafter, an embodiment of the lift type check valve of the present invention will be described with reference to FIG. 2, where the same parts as those of the conventional valve are designated by the same reference numerals.

The valve body 3 is formed into a cylindrical shape having a cylindrical cavity 6.

A piston 7 fixed to the lower end of the valve stem 5 is slidably fitted into the cavity 6.

In order to reduce the resistance when the valve body 3 and the valve stem 5 are displaced relative to each other, the valve body 3 has an upper through-hole fluid passage 8 connected to the outside near both reciprocating ends of the piston 7, and a lower through-hole through the valve body 3. A hole fluid passage 9 is provided to connect the valve body 3 to the outside.

The positions where the fluid passages 8 and 9 open into the cavity 6 in the valve body 3 are as follows:
Distance X from the upper end surface 10 and lower end surface 11 of the cavity 6, respectively
1. It's only X2 away.

Therefore, when the valve body 3 suddenly moves downward, the fluid within the distance X1 from the upper end surface 10 acts as a buffer material.

Further, when the valve body 3 suddenly moves upward, the fluid within a distance X2 from the lower end surface 11 acts as a buffer material.

Therefore, collision between the valve body 3 and the valve stem 5 or the valve seat 4 can be prevented.

FIG. 3 shows another embodiment, in which the fluid passages 8,
9, a fluid passage 12 of an upper and lower communication groove is provided on the side wall of the cylindrical cavity 6 of the valve body 3.

The fluid passage 12 is located at a distance of X1 from the upper end surface 10 and the lower end surface 11 of the cavity 6, respectively. The positions separated by X2 are communicated with each other, and as in the above embodiment, the distances X1. The fluid within the range of X2 prevents the valve body 3 from colliding with the valve stem 5 or valve seat 4.

In this embodiment, the cylindrical valve body 3 does not communicate with the outside,
Since the fluid passage 12 communicates between the upper and lower parts of the valve body 3, there is an advantage that foreign matter does not get mixed into the valve body 3, which is an advantage of this embodiment.

As described above, this check valve is designed to buffer the lower and upper end surfaces of the valve body by interposing a buffering fluid when the cylindrical valve body rises or descends.

As described above, the lift type check valve of the present invention has the effect of preventing damage caused by the valve body colliding with the valve stem and valve seat due to valve body vibration.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional lift type check valve, Fig. 2 is a sectional view showing an embodiment of the lift type check valve of the present invention, and Fig. 3 is a sectional view of an embodiment of the lift type check valve of the present invention. FIG. 3... Valve body, 4... Valve seat, 5...
...Valve stem, 6...Gap, 7...Piston, 8,9.12...Fluid passage, 10...
...Top end surface, 11...Bottom end surface.

Claims (1)

[Scope of Claims] 1. A lift-type check valve in which the valve body is guided by a valve stem and moves up and down, and when the fluid flows in the normal direction, the valve body is pushed open, and when the fluid flows in the reverse direction, it comes into contact with the valve seat and closes. , the valve body is formed into a cylindrical shape having an internal cavity, a piston fixed to the lower end of the valve stem is slidably fitted into the cavity, and when the valve body slides, the fluid inside the valve body acts as a cushioning material. A lift type check valve characterized in that a fluid passage is provided in the valve body so that the valve body can be operated. 2. The lift type check valve according to claim 1, wherein the fluid passages are formed at a certain distance from the upper and lower end surfaces of the valve body and are communicated with the outside. 3. The lift type check valve according to claim 1, wherein the fluid passage is formed inside the valve body so as to communicate between positions spaced a certain distance from the upper end face and the lower end face.