Structure of check valve

1. A check valve comprising:

a valve casing that has a collar part at an outer periphery of one end of a cylindrical part, and has a valve seat at an other end opening of the cylindrical part;

a shaft support part that has an insertion part for a shaft at a center, and in which a coupling part is formed that extends outwardly in a radial direction from the insertion part, and in which an end of the coupling part is connected to an inner periphery of the valve casing;

the shaft whose one end is inserted and secured to the insertion part of the shaft support part, and whose other end is projected;

a valve in which the shaft is inserted in a center hole in a liquid-tight manner, and that is removably seated on the valve seat; and

a biasing means that biases the valve in a seating direction, wherein

the valve of the check valve is arranged inside a flexible rubber pipe body having respective metal flanges at respective ends, and the collar part of the check valve is attached so as to be sandwiched between the flange and a flange of piping facing the flange through an annular seal body;

and the shaft remains in a fixed position when the valve is opened and closed; and

wherein

an outer diameter of the cylindrical part of the valve casing is smaller than an inner diameter of an end of an insertion side of the flexible rubber pipe body,

and wherein

the collar part of the valve casing is arranged between the flanges and an annular passage is formed between the cylindrical part and the flexible rubber pipe body,

and wherein

the collar part is of sufficient thickness to accommodate a bypass path,

and wherein

a bypass path is formed in the collar part and openably communicates with an inlet/outlet port provided at an inner periphery of the cylindrical part at which the collar part is located with an inlet/outlet port provided at a flat surface of the collar part,

and wherein

the bypass path and the annular passage communicate with each other.

2. The check valve according to claim 1 , wherein

in the collar part, formed is a plug insertion hole having the inlet/outlet port that penetrates in a radial direction from an outer periphery of the collar part, and is opened to an inside of the cylindrical part,

the bypass is formed by providing the inlet/outlet port communicating with the inlet/outlet port in an L-shaped manner at a root of the plug insertion hole and an outer periphery of the cylindrical part, and wherein

a bypass plug is screwed to an inside of the plug insertion hole, and the bypass path is opened and closed.

3. The check valve according to claim 1 , wherein the insertion part of the shaft support part, and the coupling part are integrally molded in the valve casing.

4. The check valve according to claim 1 , wherein

the valve has a valve body and a sandwiching body, a cylinder part having the center hole is integrally formed at the valve body, a valve seat contact member is arranged at the valve body, and the valve seat contact member is pressed by the sandwiching body, and wherein

a locking ring is provided adjacent to the sandwiching body, and the valve seat contact member and the sandwiching body are secured by the locking ring to configure the valve.

5. The check valve according to claim 1 , wherein

the flexible pipe body has at each of its ends a respective small flange in which a respective annular ring has been integrally buried, and the respective metal flanges are arranged at an outer periphery of the respective small flanges, and wherein

the collar part of the valve casing of the check valve comes into contact with the small flange, and is sandwiched between the metal flange and the flange of the piping facing the metal flange.

6. The check valve according to claim 1 , wherein

the flexible pipe body is formed of fluororesin,

the flexible pipe body has respective small flanges at the respective ends of the flexible pipe body, one of the small flanges being proximal to the collar part and the other of the small flanges being distal to the collar part, and the metal flange is arranged at an outer periphery of the small flange, and wherein

the collar part of the valve casing is brought into contact with the small flange which is proximal to the collar part, and the collar part is attached so as to be sandwiched between the metal flange and the flange of the piping facing the metal flange through the seal body.

7. A check valve comprising:

a valve casing that has a collar part at an outer periphery of one end of a cylindrical part, and has a valve seat at another end opening of the cylindrical part;

a shaft support part that has an insertion part for a shaft at a center, and in which a coupling part is formed that extends outwardly in a radial direction from the insertion part, and in which an end of the coupling part is connected to an inner periphery of the valve casing;

the shaft whose one end is inserted and secured to the insertion part of the shaft support part, and whose other end is projected;

a valve in which the shaft is inserted in a center hole in a liquid-tight manner and is removably seated on the valve seat; and

a biasing means that biases the valve in a seating direction, wherein

the valve of the check valve is arranged inside a bellows shaped flexible pipe body having a respective having metal flange at each end, and the collar part of the check valve is sandwiched between one of the metal flanges and a flange of piping facing the metal flange through an annular seal body;

and the shaft remains in a fixed position when the valve is opened and closed, wherein

the flexible pipe body is formed of stainless steel,

the flexible pipe body has a respective annular U-shaped ring at each end of the flexible pipe body, one of the annular U-shaped rings being proximal to an annular seal body and the other of the annular U-shaped rings being distal to the annular seal body, and each of the metal flanges is arranged at an outer periphery of the respective annular U-shaped ring, and wherein

the annular seal body is sandwiched between the collar part of the valve casing and the annular U-shaped ring which is proximal to the annular seal body, and the collar part is sandwiched between the metal flange and the flange of the piping facing the metal flange through the seal body

wherein

an annular passage is formed between the cylindrical part and the bellows shaped flexible pipe body,

and wherein

the collar part is of sufficient thickness to accommodate a bypass path, and wherein

a bypass path is formed in the collar part and openably communicates with an inlet/outlet port provided at an inner periphery of the cylindrical part at which the collar part is located with an inlet/outlet port provided at a flat surface of the collar part,

and wherein

the bypass path and the annular passage communicate with each other.

8. A check valve comprising:

a valve casing that has a collar part at an outer periphery of one end of a cylindrical part, and has a valve seat at an other end opening of the cylindrical part;

a shaft support part that has an insertion part for a shaft at a center, and in which a coupling part is formed that extends outwardly in a radial direction from the insertion part, and in which an end of the coupling part is connected to an inner periphery of the valve casing;

the shaft whose one end is inserted and secured to the insertion part of the shaft support part, and whose other end is projected;

a valve in which the shaft is inserted in a center hole in a liquid-tight manner, and that is removably seated on the valve seat; and

a biasing means that biases the valve in a seating direction, wherein

the valve of the check valve is arranged inside a flexible rubber pipe body having respective metal flanges at respective ends, and the collar part of the check valve is attached so as to be sandwiched between the flange and a flange of piping facing the flange through an annular seal body;

and the shaft remains in a fixed position when the valve is opened and closed; and

the flexible pipe body has at each of its ends a respective small flange in which a respective annular ring has been integrally buried, and the respective metal flanges are arranged at an outer periphery of the respective small flanges, and wherein

the collar part of the valve casing of the check valve comes into contact with the small flange, and is sandwiched between the metal flange and the flange of the piping facing the metal flange.