JPH11125347A - Vacuum breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify structure and prevent the occurrence of leakage of water to outside. SOLUTION: In a connection pipe 2, one end side 3 is connected to a hot water feed pipe (a vacuum break object) and the other side 4 forms an expansion part 5, and an on-off valve mechanism 6 to open and close the line 2A of the connection pipe 2 is contained in the expansion part 5 of the connection pipe 2. Further, the on-off valve mechanism 6 comprises a cylindrical valve seat 16 contained in the expansion part 5 of the connection pipe 2; a spherical valve element 12 disposed closer to the vacuum break object side than the valve seat 16; and a compression spring 11 to energize the valve element 12 against the valve seat 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum breaker, and more particularly to a vacuum breaker whose structure is simplified and leakage to the outside is prevented.

[0002]

2. Description of the Related Art As shown in FIG. 5, a bathroom hot water supply system includes a water heater Wa, as shown in FIG.
Dedicated metal fittings Ba installed in hot water supply pipe Pa and bathtub Bu
There is a bath hot water supply system in which hot water is supplied directly to the bathtub Bu via the hot water supply system. In this bathroom hot water system,
A vacuum breaker Va is installed on a hot water supply pipe Pa provided between the hot water supply Wa and the metal fitting Ba of the bath tub Bu in order to prevent hot water in the bath tub Bu from flowing back into the water pipe and contaminating the tap water. Have been. That is, the hot water supply pipe Pa for supplying hot water to the bathtub Bu has a water heater open / close valve Vb.
And a check valve Vc are interposed.
A vacuum breaker Va is mounted between the valve and the check valve Vc via a connection pipe 30.

In this bathroom hot water supply system, a bathtub B
The hot water filling or reheating is completed, and the water heater open / close valve Vb
Is closed and hot water supply is stopped, the pressure in the hot water supply pipe Pa becomes negative due to the head of the bathtub, but the vacuum breaker Va operates to introduce air into the hot water supply pipe Pa,
The negative pressure is released. Therefore, it is possible to prevent the hot water supply pipe Pa from becoming negative pressure and the hot water in the bathtub Bu flowing backward to the clean water side to contaminate the tap water.

Meanwhile, a conventional vacuum breaker Va
As shown in FIG. 6, a cylindrical valve body 31 having a through hole 31a and a cylindrical valve seat body 3 having a through hole 32a are formed.
2 are combined so that the two through holes 31a and 32a are continuously formed as one through hole, and the distal end of the valve body 31 serves as a valve seat 33, and the valve spring housed in the through hole 31a of the valve body 31. The spherical valve element 34 is configured to be pressed against the valve seat 33 by 35.

When the pressure of the through hole 31a is lower than that of the through hole 32a, the valve body 34 separates from the valve seat 33 to form a gap between the valve body 34 and the through holes 31a, 32a. When the negative pressure state is eliminated by communicating the two through holes 31a and 32a, and the negative pressure state is eliminated, the valve body 34 is urged by the valve spring 35 and pressed against the valve seat 33, and the through hole 32a is closed. Closed by the body 34, the through holes 31a, 3
The communication of 2a is cut off, and the vacuum break function of the vacuum breaker Va is stopped. When the vacuum break function is performed, the hot and cold water accumulated in the vacuum breaker Va is discharged from the drain tube 3.
It is configured to be discharged out of the system through 6. In the vacuum breaker Va, the valve body 3
The two are connected by welding so that no leakage occurs between 1 and the connection pipe 30.

However, the conventional vacuum breaker V
a requires that a through hole 31a having a complicated structure capable of receiving the valve spring 35 and inserting the rear end of the connection pipe 30 be formed in the valve main body 31, and
In order to prevent leakage between the valve body 31 and the connection pipe 30, welding must be performed between the two, and thus there is a problem that not only the structure is complicated but also the manufacturing cost is high.

Further, damage occurs at a welded portion connecting the connection pipe 30 and the valve body 31, or the valve body 31 and the valve seat body 3 are damaged.
If the outer packing 37 that seals the second joint is damaged, water leakage (external leakage) to the outside of the vacuum breaker Va occurs, and in some cases, the leaked water is disposed inside the water heater Wa. There is a problem that the electrical component board or the like may be wet and cause a failure.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a vacuum breaker whose structure can be simplified and water leakage to the outside can be avoided. I do.

[0009]

According to a first aspect of the present invention, there is provided a vacuum breaker, wherein one end of the vacuum breaker is connected to a vacuum break object, and the other end opened to the atmosphere is a predetermined distance from the tip. It is formed by disposing a connection pipe having a large inner diameter to be an expanded portion, and a valve seat for opening and closing and a valve seat for receiving the valve body in the expanded portion. In the negative pressure state where the pressure is negative from the end side, the valve body separates from the valve seat and one end side and the other end side of the connection pipe are in a communicating state, and when the negative pressure state is eliminated, the valve body is in the valve seat. By returning, one end side and the other end side of the connection pipe are shut off,
An on-off valve mechanism for opening and closing the pipe of the connection pipe is provided.

In a vacuum breaker according to a second aspect of the present invention, the opening / closing valve mechanism is disposed on a cylindrical valve seat accommodated in an expanded portion of the connection pipe, and on a vacuum break target side of the valve seat. It is characterized by comprising a valve element and a compression spring for urging the valve element against a valve seat.

According to a third aspect of the present invention, in the vacuum breaker, the valve seat is formed with a cylindrical valve seat main body and a protruding portion (rib) orbiting the outer peripheral surface. A ring-shaped packing made of an elastic material fitted in such a manner that one end thereof protrudes in the axial direction from an end of the valve seat main body on an outer periphery of a tip portion on the opposite side; The protruding part (protruding part) in close contact with the valve body and exerts a sealing function with the valve body surface,
It is characterized in that at least the ridges on the outer peripheral surface of the packing come into close contact with the inner surface of the expanded tube portion and exhibit a sealing function between the inner surface of the expanded tube portion.

In the vacuum breaker according to a fourth aspect of the present invention, a flange protruding radially outward is formed on a rear end edge of the cylindrical valve seat main body, and the flange abuts on an end face of the expanded pipe portion. The valve seat body is held at a predetermined position in the expanded portion by being in contact with each other.

According to a fifth aspect of the present invention, there is provided a vacuum breaker, wherein the valve seat body has a concave portion (groove) orbiting an outer peripheral surface.
Is formed, and the expanded portion is caulked from the outer peripheral surface side,
It is characterized in that the swaged portion of the expanded portion is bitten into the concave ridge portion so that the valve seat body does not fall out of the expanded portion.

A vacuum breaker according to claim 6 of the present application is:
The drain tube is extrapolated to the expanded portion of the connection pipe, and the drain tube is drawn out of the facility.

[0015]

In the case of the vacuum breaker of the present invention, an opening / closing valve mechanism having a valve element housed in the expanded portion of the connection pipe and a valve seat for receiving the valve element operates, and one end on the connection side to the vacuum break target. While the side is at a lower pressure than the other end released to the atmosphere, the valve body is separated from the valve seat, the conduit of the connection pipe is opened, and one end and the other end of the connection pipe communicate with each other. At the time when the negative pressure state of the vacuum break target is eliminated, and at the time when the negative pressure state is eliminated, the valve body returns to the valve seat, the pipe of the connection pipe is closed, and the one end side and the other end side of the connection pipe are closed. The communication is cut off, the communication state (open state) between the vacuum break target and the outside is released, and the vacuum break function stops.

Further, in the case of the vacuum breaker of the present invention, an opening / closing valve mechanism for opening / closing the pipe of the connection pipe is housed in the expansion section of the connection pipe, and the expansion section of the connection pipe functions as a valve body (casing). This eliminates the need for welding the valve body and the connecting pipe as in the related art, and allows the structure to be simplified.

Furthermore, since the on-off valve mechanism is housed in a welded portion where there is a possibility of water leakage to the outside or a pipe expansion portion of a seamless connection pipe, water leakage to the outside is reliably prevented, and reliability is improved. Performance can be greatly improved.

Further, as in claim 2, the on-off valve mechanism comprises:
A tubular valve seat housed in the expanded portion of the connection pipe, a valve body disposed on the side of the vacuum break from the valve seat, and a compression spring for urging the valve body toward the valve seat are provided. If
The opening / closing valve mechanism can be formed by simply combining simple parts, and the vacuum breaker can be reduced in size and the structure can be simplified.

According to a third aspect of the present invention, a valve seat constituting the on-off valve mechanism is formed with a cylindrical valve seat body and a convex portion (rib) orbiting the outer peripheral surface. When the packing is made of a material made of an elastic material, the packing is in close contact with the valve body to perform a sealing function with the valve body surface, and at the same time, the convexity of the outer peripheral surface of the packing is used. Since the ridges are in close contact with the inner surface of the expanded portion and exert a sealing function between the inner surface of the expanded portion, the opening / closing valve mechanism can be reliably formed only by combining simple parts, and the structure of the vacuum breaker Can be further simplified.

[0020] Further, the structure of the vacuum breaker is further improved in that the seal between the valve seat body and the valve body surface and the seal between the valve seat body and the inner surface of the expanded portion are both performed by one packing. Simplification can be achieved.

Further, a flange protruding radially outward is formed at the rear end edge of the cylindrical valve seat body, and the flange is brought into contact with the end face of the expanded portion. In this case, the flange portion functions as a stopper, and the valve seat body can be reliably held at a predetermined position in the expanded portion, so that the structure can be simplified and the assembly process can be simplified.

According to a fifth aspect of the present invention, a recessed portion (groove) is formed in the valve seat body so as to go around the outer peripheral surface, the expanded portion is crimped from the outer peripheral surface side, and the swaged portion is cut into the concave portion. In this case, the valve seat body can be reliably held by the expanded portion, and the reliability can be improved without requiring a complicated structure or a manufacturing process.

Further, when the drain tube is extrapolated to the expanded portion of the connecting pipe and the drain tube is drawn out of the equipment, a vacuum break function is exhibited and the liquid is vacuumed. Even when the fluid flows into the breaker, the fluid can be discharged to a predetermined position through the drain tube, and when there is an internal leak caused by damage to the opening / closing valve mechanism, the fluid can be discharged to the predetermined position through the drain tube. It is possible to discharge the fluid to the position, and it is possible to reliably prevent the fluid from leaking into the equipment and improve the reliability.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be shown and features thereof will be described in more detail. FIG.
FIG. 2 is a cross-sectional view showing a vacuum breaker according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a state where the vacuum breaker is connected to a hot water supply pipe to be subjected to vacuum break.

The vacuum breaker Va has one end 3
Is connected to a hot water supply pipe Pa (FIG. 2) to be subjected to a vacuum break, and the other end 4 is open to the atmosphere, and has an expanded portion 5 having a larger inside diameter by a predetermined distance from the end. It comprises a connecting pipe 2 and an opening / closing valve mechanism 6 housed in the expanding section 5 and opening and closing the pipe 2A of the connecting pipe 2. The opening / closing valve mechanism 6 includes a cylindrical valve seat 16, a metal spherical valve body 12 disposed on the hot water supply pipe Pa side of the valve seat 16, and a compression spring for urging the valve body 12 against the valve seat 16. 11 is formed. Further, the connecting pipe 2 has a structure in which the expanded portion 5 is formed integrally with another portion (non-expanded portion) 7 and has no welded portion or connected portion.

The opening / closing valve mechanism 6 moves the valve body 12 away from the valve seat 16 while the one end 3 of the connection pipe 2 is at a lower pressure than the other end 4 opened to the atmosphere. The pipe 2A of the connection pipe 2 is opened, and the one end 3 and the other end 4 of the connection pipe 2 communicate with each other to eliminate the negative pressure state. Returning to the valve seat 16, the pipe 2A of the connection pipe 2 is closed, the communication between the one end 3 and the other end 4 of the connection pipe 2 is cut off, and the communication state (open state) with the outside is released, and the vacuum break is performed. The function is configured to be stopped.

A drain tube 8 for guiding the hot and cold water flowing out when the vacuum break function is exerted to a predetermined position is externally inserted into the expanded portion 5 of the connection pipe 2. 5 is securely fixed. The connection pipe 2 is usually made of metal, but may be made of another material such as a synthetic resin as long as conditions such as heat resistance and mechanical strength are satisfied. There is no special restriction on the shape of the connection pipe 2,
It is possible to bend or bend at an arbitrary position according to the positional relationship with the hot water supply pipe Pa or the like.

The valve seat 16 has a stepped portion 1 having an outer diameter smaller than other portions on the outer periphery of a tip portion 13b facing the valve body 12.
A cylindrical valve seat main body 13 formed with 3a and a ridge portion (rib) 15b circling the outer peripheral surface in the circumferential direction;
One end of the valve seat body 13 is provided on the step portion 13a of the valve seat body 13.
And a ring-shaped packing 15 made of an elastic material which is fitted so as to form a protruding portion 15a protruding in the axial direction from an end of the valve body 12. The protruding portion 15a of the packing 15 is in close contact with the valve body 12. As a result, at the same time, a sealing function is exerted between the valve body 12 and the outer peripheral surface of the packing 15, so that at least the protruding ridges 15 b are in close contact with the inner surface of the expanded tube portion 5, thereby sealing between the inner surface of the expanded tube portion 5. It is configured to perform its function. Therefore, in this embodiment, the projecting portion 15a of the packing 15 fitted into the step portion 13a of the valve seat main body 13 substantially functions as a valve seat.

A flange 13c is formed on the rear end edge of the valve seat body 13 so as to protrude radially outward.
The valve seat body 13 is configured to be accurately loaded at a predetermined position by abutting the distal end surface 5a of the expanded portion 5 with the 3c. The flange 13c also functions as a stopper for the drain tube 8. Further, the valve seat body 13 is formed with a recessed portion (groove) 13d orbiting the outer peripheral surface, and by caulking the expanded portion 5 from the outer peripheral surface side, the swaged portion 5b of the expanded portion 5 is recessed. The valve seat body 13 can be securely held so as not to fall out of the expanded tube portion 5 by being cut into the portion 13d. In addition, caulking is
For example, it can be easily performed by a method of hitting a plurality of places with a punch along the circumferential direction.

Next, a hot water supply pipe (a vacuum break target) Pa of a water heater Wa for hot water supply in a bathroom as shown in FIG.
Next, the operation of the vacuum breaker Va will be described, taking as an example the case where the vacuum breaker Va of this embodiment is installed.

As shown in FIGS. 2 and 5, the vacuum breaker Va is attached to a hot water supply path 21 formed by connecting a hot water supply Wa and a metal fitting Ba of a bathtub Bu with a hot water supply pipe Pa. Is connected by inserting one end 3 of the connection pipe 2 into a connection hole 20 provided at an end of the check valve Vc so as to be located between the water heater open / close valve Vb and the check valve Vc in the hot water supply path 21. By doing so, it is attached via the connection pipe 2.

The check valve Vc is, as shown in FIG.
A valve body 18 for opening and closing and a compression spring 22 for urging the valve body 18 to press around the opening 19a formed in the valve body 19 are provided in the valve body 19,
When hot water is not supplied from the upstream-side water heater open / close valve Vb, the valve element 18 is pressed around the opening 19a of the valve body 19 by the compression spring 22, and the opening 19a is closed to close the water heater open / close valve Vb. When hot water is supplied from (FIG. 5), the valve element 18 is pushed to the left in FIG.
The check valve Vc is configured so as to be away from the periphery of “a” and open (FIG. 4).

First, when hot water supply from the hot water supply opening / closing valve Vb is started, as shown by an arrow S1 in FIG.
4, the hot water flows through the valve element 18 to the right due to the pressure of the hot water, and the check valve Vc is opened, as shown by the arrow S2 in FIG. Supplied. The hot water is supplied to the connection pipe 2 of the vacuum breaker Va.
A little into the pipe line 2A, but the spherical valve element 1
2 is pressed by the valve seat 16, so that the vacuum breaker V
a maintains the closed state.

When the hot water supply from the hot water supply opening / closing valve Vb is stopped, the hot water supply pipe Pa is moved by the water head to the bathtub Bu.
The inside is in a negative pressure state, and one end side (one end side of the connection pipe 2) 3 of the vacuum breaker Va has a negative pressure from the other end side 4. As shown in FIG. The valve breaker Va shifts to the open state, and the valve element 18 of the check valve Vc is pushed leftward by the negative pressure to move away from the periphery of the opening 19a of the valve body 19, and The stop valve Vc is also opened. As a result, the hot water supply pipe Pa communicates with the atmosphere via the connection pipe 2, and the outside air is immediately introduced into the hot water supply pipe Pa through the connection pipe 2, and the negative pressure state in the hot water supply pipe Pa is eliminated. As a result, it is possible to reliably prevent a situation in which the water in the bathtub Bu flows backward and mixes with the clean water. That is, according to the vacuum breaker of the present invention, it is possible to stop the backflow of bathtub water with a double check together with the check valve, and to set the space between the hot-water supply on-off valve and the check valve to the atmosphere ( (Water) so that the water side and the bathtub water side do not come into direct contact with each other, so that both sides can be reliably cut off and sufficient reliability can be secured.

According to the vacuum breaker Va of this embodiment, the opening / closing valve mechanism 6 for opening and closing the pipe 2A of the connection pipe 2 is accommodated in the expansion section 5 of the connection pipe 2, and the expansion section 5 of the connection pipe 2 is provided. Functions as a valve body (casing), it is not necessary to weld the valve body and the connecting pipe as in the conventional case, and the structure can be simplified. Since it is housed in the expanded tube portion 5 without the water, it is possible to reliably prevent water leakage to the outside and to greatly improve the reliability.

Further, since the drain tube 8 is attached to the vacuum breaker Va, even if internal leakage occurs in the on-off valve mechanism 6, the leaked hot water is discharged to a predetermined position by the drain tube 8. Therefore, it is possible to reliably prevent a situation in which the electrical equipment board and the like disposed inside the water heater is wetted to cause a failure.

The opening / closing valve mechanism 6 includes a valve seat 16 and a valve body 1.
The valve seat body 1 is formed by simple components of the compression spring 11 and the ring-shaped packing 15.
Since sealing is performed between the valve body 3 and the valve body 12 and between the valve seat body 13 and the inner surface of the expanded portion 5, the structure of the vacuum breaker can be further simplified. Further, due to the ridges 15b formed on the outer surface of the packing 15, the tightness between the valve seat body 13 and the inner surface of the expanded portion 5 is improved, and internal leakage of the vacuum breaker Va can be avoided.

In the above embodiment, the case where the vacuum breaker is used as a vacuum breaker of a hot water supply pipe for supplying hot water to a bathroom has been described as an example. However, the vacuum breaker of the present invention is a water supply pipe for flushing a toilet or a bidet. It can be widely used. Further, the vacuum breaker of the present invention can be applied to a supply system of a liquid other than water or a vacuum break of a gas supply system.

Further, the present invention is not limited to the above embodiment in other respects, and the specific shape and structure of each member such as the on-off valve mechanism and the valve seat and valve body constituting the same, With respect to the length and diameter of the expanded portion of the connecting pipe, various applications and modifications can be made within the scope of the invention.

[0040]

According to the vacuum breaker of the present invention, an opening / closing valve mechanism for opening and closing the pipe of the connection pipe is accommodated in the expansion section of the connection pipe, and the expansion section of the connection pipe having an integral structure is provided in the valve body (casing). ), It is not necessary to weld the valve body and the connecting pipe as in the related art, and the structure can be simplified. In addition, the on-off valve mechanism is housed in the welded area where there is a possibility of water leakage to the outside and the expanded part of the seamless connection pipe, so that water leakage to the outside is reliably prevented, and reliability is greatly improved. Can be improved.

According to a second aspect of the present invention, there is provided a vacuum breaker, wherein the opening / closing valve mechanism includes a tubular valve seat housed in the expanded portion of the connection pipe, and a valve body disposed on the side of the vacuum break from the valve seat. And a compression spring that biases the valve body against the valve seat, it is possible to form an opening / closing valve mechanism by simply combining simple components, and to reduce the size and structure of the vacuum breaker. Can be simplified.

Further, as in the vacuum breaker according to the third aspect, the valve seat constituting the opening / closing valve mechanism is formed of a cylindrical valve seat body and a protruding ridge (rib) orbiting the outer peripheral surface. When a packing made of an elastic material fitted to the tip of the main body is used, the packing comes into close contact with the valve body to exert a sealing function between the valve body surface and the outer periphery of the packing. The convex ridges on the surface are in close contact with the inner surface of the expanded portion and exhibit a sealing function between the inner surface of the expanded portion, so that the on-off valve mechanism can be reliably formed only by combining simple parts, and the vacuum The structure of the breaker can be further simplified.

In addition, one packing provides both a seal between the valve seat body and the valve body surface and a seal between the valve seat body and the inner surface of the expanded portion. Simplification can be achieved.

Further, like the vacuum breaker according to the fourth aspect, a flange protruding radially outward is formed on the rear end edge of the cylindrical valve seat body, and this flange abuts on the end face of the expanded pipe portion. In such a case, the flange portion functions as a stopper, so that the valve seat body can be securely held at a predetermined position in the expanded portion, and the structure and the assembly process can be simplified. become.

Further, like the vacuum breaker of the fifth aspect, a concave portion (groove) is formed in the valve seat body so as to go around the outer peripheral surface, and the expanded portion is crimped from the outer peripheral surface side to form the concave portion. When it is made to bite into the portion, the valve seat body can be securely held in the expanded portion, and the reliability can be improved without requiring a complicated structure or a manufacturing process.

Further, when the drain tube is extrapolated to the expanded portion of the connection pipe and the drain tube is drawn out of the facility as in the vacuum breaker of claim 6, a vacuum break function is exhibited. If liquid flows into the vacuum breaker,
It is possible to discharge fluid to a predetermined position through the drain tube, and also to discharge fluid to the predetermined position through the drain tube in the event of internal leakage caused by damage to the on-off valve mechanism. Therefore, it is possible to reliably prevent the fluid from leaking into the equipment and improve the reliability.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a vacuum breaker according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state (negative pressure state) in which a vacuum breaker according to an embodiment of the present invention is connected to a hot water supply pipe to be subjected to vacuum break.

FIG. 3 is a sectional view showing an open state of the vacuum breaker according to the embodiment of the present invention.

FIG. 4 is a sectional view showing an open state of a check valve provided on the hot water supply pipe.

FIG. 5 is a diagram showing an example of a bathroom hot water supply system.

FIG. 6 is a sectional view showing a conventional vacuum breaker.

[Explanation of symbols]

 2 Connection Pipe 2A Connection Pipe Line 3 One End of Connection Pipe 4 Another End of Connection Pipe 5 Expanded Part 5a Tip Surface 5b Caulked Part 6 Opening and Closing Valve Mechanism 8 Drain Tube 7 Non-Expanded Part 9 Hose Band 11 Compression Spring 12 Spherical 13 Valve seat body 13a Stepped portion 13b Tip of valve seat body 13c Flange 13d Concave ridge (groove) 15 Packing 15a Protrusion of packing 15b Convex ridge (rib) 15c Outer peripheral surface of packing 16 Valve seat Ba Dedicated metal fittings Bu Bathtub Pa Hot water supply pipe Va Vacuum breaker Vb Water heater open / close valve Vc Check valve Wa Water heater

Claims (6)

[Claims] 1. A connecting pipe having one end connected to a vacuum break target and the other end open to the atmosphere, the inner diameter of which is increased by a predetermined distance from the tip to form an expanded portion, and a valve body for opening and closing. And a valve seat that receives the valve body is disposed in the expanded portion, and the valve body is separated from the valve seat in a negative pressure state in which one end of the connection pipe has a negative pressure from the other end. One end side and the other end side of the connection pipe are in a communicating state, and in a state where the negative pressure state is eliminated, the valve body returns to the valve seat and one end side and the other end side of the connection pipe are in a cutoff state, so that the connection pipe is closed. A vacuum breaker comprising: an on-off valve mechanism for opening and closing a pipeline. 2. The valve system according to claim 1, wherein the opening / closing valve mechanism includes a tubular valve seat housed in an expanded portion of the connection pipe, a valve body disposed on the side of the vacuum break from the valve seat, and a valve body mounted on the valve seat. 2. The vacuum breaker according to claim 1, further comprising a compression spring for urging. 3. The valve seat according to claim 1, wherein the valve seat is formed with a cylindrical valve seat body, and a convex portion (rib) orbiting the outer peripheral surface. A ring-shaped packing made of an elastic material fitted in such a manner that the side protrudes in the axial direction from the end of the valve seat body, and a portion (protruding portion) of the packing protruding in the axial direction is provided. At the same time, the sealing function is exerted between the valve body surface and the valve body surface, and at least the ridges on the outer peripheral surface of the packing come into close contact with the inner surface of the expanded part to provide a sealing function between the inner surface of the expanded part. The vacuum breaker according to claim 1, wherein the vacuum breaker is configured to perform. 4. The valve seat main body is expanded by forming a flange protruding radially outward at a rear end edge of the cylindrical valve seat main body and abutting the flange portion on an end surface of the pipe expanding portion. The vacuum breaker according to any one of claims 1 to 3, wherein the vacuum breaker is held at a predetermined position in the unit. 5. The valve seat body is provided with a concave portion (groove) orbiting the outer peripheral surface, and the expanded portion is caulked from the outer peripheral surface side, so that the caulked portion of the expanded portion is cut into the concave portion. The vacuum breaker according to any one of claims 1 to 4, wherein the valve seat body is prevented from falling off from the expanded portion. 6. The vacuum breaker according to claim 1, wherein a drain tube is extrapolated to an expanded portion of the connection pipe, and the drain tube is drawn out of a system of the equipment.