JP2000018406A - Check valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a back flow by securing sufficient sealing when micro pressure is applied to an outlet. SOLUTION: When an inlet 6 of a casing 2 applies fluid pressure to a valve element 3, a check valve 1 allows the fluid to flow by separating the valve element 3 from a valve seat 8 in opposition to energization force of a spring 4. When an outlet 7 of the casing 2 applies fluid pressure, the check valve 1 prevents the fluid from flowing back by pressing the valve element 3 vertically to the valve seat 8 based on the energizion force of the spring 4 and the fluid pressure. The valve element 3 includes multiple center ribs 10 slidable along the inlet 6 to guide the valve element 3 itself toward the valve seat 8, and multiple outer ribs 11 slidable along the casing 2 to guide the valve element 3 toward the casing 2. The spring 4 is installed near the outside of an outer diameter of the valve seat 8 by engaging each outer rib 11 with a stopper 5, and presses the valve element 3 vertically to the valve seat 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve which is applied to a fluid device for a liquid, a gas or the like and prevents a backflow of the fluid so that the fluid flows only in one direction.

[0002]

2. Description of the Related Art Conventionally, a check valve for preventing a backflow of a fluid and allowing a fluid to flow only in one direction is sometimes provided in a flow passage of a fluid device because of the necessity of fluid control.

FIG. 8 shows an example of a check valve 51 provided in a flow path of a liquid device of this type. The check valve 51 includes a cylindrical casing 52 and a valve body 54 provided in the casing 52 to close an inlet 53 thereof. The valve element 54 includes a valve portion 54a that matches the tapered surface 55 of the inlet 53, an O-ring 56 mounted on the outer periphery of the valve portion 54a, and a shaft portion 54 extending downward from the center of the valve portion 54a.
b. The shaft portion 54b is attached to a bearing 52a provided at the center of the casing 52, and is slidable in the axial direction, that is, in the vertical direction in FIG. The valve element 54 is mounted on the bearing 5 such that the valve portion 54a contacts the tapered surface 55.
It is urged by a coil spring 57 mounted on the outer periphery of 2a. Therefore, the function of the check valve 51 sealing the liquid is obtained by pressing the O-ring 56 against the tapered surface 55 based on the urging force of the coil spring 57.

[0004] As one of the liquid devices to which the above-described check valve 51 is applied, for example, there is a hot water supply device for a bath as shown in FIG. The hot water supply device includes a hot water supply unit 62 for making new hot water supplied to a bathtub 61 and a kitchen, a reheating unit 63 for reheating the hot water accumulated in the bathtub 61 as necessary, and a hot water supply unit. It has a connection portion 64 for connecting the reheating portion 63 to the reheating portion 63. The hot water supply unit 62 heats the water supplied to the cold water pipe 65 with the heat exchanger 66 and sends the water to the hot water pipe 67. The reheating unit 63 circulates the hot water in the bathtub 61 through a circulation pipe 69 by a circulation pump 68, heats the hot water in another heat exchanger 70, and circulates the hot water through the circulation pipe 69 to the bathtub 61. The connection part 64 connected to the hot water supply pipe 67 has an on-off valve 72, a backflow prevention device 73, and a switching valve 74 connected in series to each other in the connection pipe 71. The on-off valve 72 is used to add hot water from the hot water supply unit 62 to the heating unit 63.
It is opened to supply to the bathtub 61 via the. The switching valve 74 is switched when selecting whether to supply hot water from the hot water supply unit 63 to the bathtub 61 or to circulate hot water in the bathtub 61 for reheating. Therefore, in order to supply fresh hot water to the bathtub 61, the switching valve 74
Is switched to open the on-off valve 72, so that the hot water supply unit 62
Hot water is supplied to the bathtub 61 through the connecting portion 64 and the reheating portion 63.
Down to On the other hand, in order to reheat the hot water in the bathtub 61, the switching valve 74 is switched, the circulation pump 68 is operated, and the hot water in the bathtub 61 is circulated through the circulation pipe 69 while being heated by the heat exchanger 70. The backflow preventer 73 is provided with the hot water supply pipe 6.
7 is cut off from the circulation pipe 69 to prevent hot water in the bathtub 61 from flowing back to the cold water pipe 65, the heat exchanger 66, and the hot water supply pipe 67.

Here, as the above-mentioned backflow prevention device 73, there is a device in which the above-mentioned two check valves 51 are provided in series. The reason for providing two check valves 51 in series is to enhance the function of preventing hot water from flowing back.

[0006]

However, the check valve 51 employed in the backflow preventer 73 as described above has a problem in its structure in preventing the backflow when a slight pressure is applied to the outlet 58 thereof due to its structure. . That is, in the bath water supply apparatus as described above, when the amount of hot water in the bath tub 61 becomes low, new hot water is automatically supplied to the bath tub 61 to perform control for keeping the water level in the bath tub 61 constant. is there. Here, bathtub 6
In order to replenish the hot water, the connecting pipe 71 is connected to the circulation pipe 69.
The switching valve 74 is switched in order to enable communication with the outlet port. At this time, the secondary pressure due to the hot and cold water in the bathtub 61 may be applied to the outlet 58 of the check valve 51. The secondary pressure applied to the outlet 58 changes depending on the positional relationship between the check valve 51 and the bathtub 61, specifically, the relationship between the water level of the bathtub 61 and the height position of the check valve 51. Two check valves 5
If the check valve 51 on the downstream side has a problem, the secondary pressure due to hot water may also be applied to the outlet 58 of the check valve 51 on the upstream side.

For example, if the water level in the bathtub 61 is sufficiently higher than the positions of the two check valves 51, the secondary pressure applied to their outlets 58 will be sufficiently large. Therefore, a force that strongly presses the valve body 54 against the tapered surface 55 acts on the check valve 51, and the check valve 51 is firmly closed. Alternatively, if the water level in the bathtub 61 is sufficiently lower than the position of the two check valves 51, no secondary pressure is applied to their outlets 58. Therefore, there is no possibility that the hot and cold water in the bathtub 61 flows back through the two check valves 51 to the hot water supply unit 62 side.

However, when the water level in the bathtub 61 is almost the same as the position of the two check valves 51, a slight pressure may be applied to the outlets 58. Accordingly, the check valve 51 receives a force for pressing the valve body 54 against the tapered surface 55, but the force is not sufficiently strong, and in some cases, the posture of the valve body 54 tends to be unstable. is there. In particular,
In the above-described check valve 51, as shown in FIG. 8, the central shaft portion 54b of the valve body 54 is structured to be supported by the bearing 52a, and therefore, the set clearance between the shaft portion 54b and the bearing 52a ( Depending on the size of the clearance required to allow the relative movement between the two 54b and 52a), the shaft 54
b may be slightly shifted with respect to the center axis of the inlet 53. In addition, the check valve 51 has a structure in which the O-ring 56 of the valve portion 54a is in contact with the tapered surface 55 in order to ensure the sealing performance. Therefore, all of the forces acting on the valve element 54 to close the check valve 51 act as a force for pressing the O-ring 56 perpendicularly to the tapered surface 55, that is, a force most effective for obtaining the sealing property. Not in translation. Therefore, when the valve element 54 is slightly tilted by the action of the slight pressure, or when the center axis of the valve element 54 is shifted from the center axis of the inlet 53, a gap is generated between the O-ring 56 and the tapered surface 55, and conversely. There is a possibility that the stop valve 51 may allow the backflow of hot and cold water. That is, the dirty hot water in the bathtub 61 may flow backward to the hot water supply unit 62 side, which is a problem in hygiene management of the hot water supply unit 62.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a purpose thereof is to provide a non-return device which secures sufficient sealing performance when a small pressure is applied to an outlet to prevent a backflow. It is to provide a valve.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, an invention according to claim 1 is provided with a cylindrical casing having an inlet and an outlet, and provided in the casing corresponding to the inlet. Valve seat, a valve body provided in the casing corresponding to the valve seat, and a spring for pressing the valve body perpendicularly to the valve seat, and fluid pressure was applied to the valve body from the inlet. Sometimes, the valve body is separated from the valve seat against the urging force of the spring to allow fluid flow, and when fluid pressure acts on the valve body from the outlet, the valve is set based on the urging force of the spring and the fluid pressure. A check valve for preventing backflow of fluid by a body being pressed perpendicularly to a valve seat, provided on the valve body to guide movement of the valve body with respect to the valve seat, and provided on an inner wall of an inlet. Can slide along A first guide part, which is provided on the outer periphery of the valve body for guiding the movement of the valve body with respect to the casing, and is slidable along the inner wall of the casing, and a spring. The valve body is engaged with the valve body at a position closer to the outside than the outer diameter of the seat, and the valve body is pressed vertically against the valve seat by the spring.

According to the above arrangement, the first guide provided on the valve body slides along the inner wall of the inlet corresponding to the valve seat, thereby guiding the movement of the valve body with respect to the valve seat. .
Therefore, the movement of the portion of the valve body close to the valve seat that greatly affects the sealing performance is guided by the first guide portion along the central axis of the inlet. In addition, the movement of the valve body with respect to the casing is guided by the second guide portion provided on the outer periphery of the valve body sliding along the inner wall of the casing. Therefore, the movement of the valve body is controlled by the second guide portion.
It will be guided along the central axis of the casing.
As described above, the movement of the valve body with respect to the valve seat is guided with a stable posture by the cooperation of the two types of guide portions. Since the valve body is biased by the spring at a position closer to the outside than the outer diameter of the valve seat, the biasing force of the spring acts uniformly on the contact surface of the valve seat via the valve body. Also, since the valve body is pressed perpendicularly to the valve seat, all of the forces acting on the valve body to close the check valve effectively act as forces for pressing the valve body against the valve seat. become.

According to a second aspect of the present invention, in order to achieve the above object, in the configuration of the first aspect, at least one of a portion of the valve body to be pressed against the valve seat and at least one of the valve seat is made of a rubber valve. The purpose is to make it a sheet.

According to the above construction, in addition to the operation of the first aspect, the rubber valve seat is interposed between the valve body and the valve seat, and the degree of adhesion between the two is improved. I do.

According to a third aspect of the present invention, in order to achieve the above object, in the configuration of the first or second aspect of the present invention, the first guide portion is provided with a plurality of projections protruding from the valve body. A central rib; a second guide portion having a plurality of outer peripheral ribs radially protruding from an outer periphery of the valve body; and each of the outer peripheral ribs extending along a moving direction of the valve body. It is intended that the present invention has the following features: a spring and a coil spring that includes the legs and engages with the outer peripheral ribs.

According to the above construction, in the invention of the first or second aspect, in particular, the plurality of central ribs provided on the valve body slide along the inner wall of the inlet, so that the valve with respect to the valve seat is provided. The movement of the body is guided. Therefore, the movement of the portion of the valve body close to the valve seat that greatly affects the sealing performance is guided along the central axis of the inlet by the plurality of central ribs. In addition, a plurality of outer peripheral ribs provided on the outer periphery of the valve body slide along the inner wall of the casing,
The movement of the valve body with respect to the casing is guided. Therefore,
The movement of the valve body is guided along the central axis of the casing by the plurality of outer peripheral ribs. As described above, the movement of the valve body with respect to the valve seat is guided with a stable posture by the cooperation of the center rib and the outer peripheral rib.
Since the valve element is urged by the coil springs that include the plurality of legs and engage with the outer peripheral ribs, the coil springs are positioned by the legs with respect to the valve element, and the urging force of the coil springs is reduced. It acts equally on the contact surface of the valve seat via the valve element. Also, since the valve body is pressed perpendicularly to the valve seat, all of the forces acting on the valve body to close the check valve effectively act as forces for pressing the valve body against the valve seat. become.

According to a fourth aspect of the present invention, in order to achieve the above object, a fluid is allowed to pass between the outer periphery of the valve body and the inner periphery of the coil spring in the structure of the third aspect. The purpose of this is to provide a gap for the valve body, and to make the outer peripheral edge of the valve body corresponding to the gap a tapered surface.

According to the above construction, in addition to the operation of the third aspect of the present invention, the passage of the fluid is permitted by the gap between the outer periphery of the valve body and the inner periphery of the coil spring. The fluid flow path when opened is ensured. Further, since the outer peripheral edge of the valve body corresponding to the gap forms a tapered surface, the flow path resistance in the gap is reduced.

According to a fifth aspect of the present invention, in order to achieve the above object, in the configuration of the third or fourth aspect, the outer surface of each leg is inclined toward the inside of the valve body. The intent is to have it done.

According to the above construction, in addition to the effect of the third or fourth aspect of the present invention, since the outer surface of each leg is inclined, the friction between each leg and the coil spring is reduced. As a result, the movement between the valve body and the coil spring becomes smooth.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a check valve according to the present invention will be described below in detail with reference to the drawings. In this embodiment, the check valve is applied to a bath water heater, and the basic configuration of the water heater is the same as the conventional one shown in FIG. That is, the check valve of this embodiment is applied to the check valve 73 of the connecting portion 73 as in the conventional case. Accordingly, in the following, the hot water supply device for a bath will be described with reference to FIG.

FIGS. 1 and 2 are sectional views showing a check valve 1 according to the present embodiment, and FIG. 3 is a front view showing the check valve with a part thereof cut away. The check valve 1 includes a casing 2, a valve body 3, a coil spring 4, and a stopper 5. The stopper 5 forms a part of the casing 2. Casing 2
Is cylindrical and has an inlet 6 and an outlet 7. The casing 2 has a valve seat 8 provided therein corresponding to the inlet 6.
Having. The valve body 3 has a valve seat 8 in the casing 2.
Is provided in correspondence with. The coil spring 4 includes the valve body 3
Is pressed against the valve seat 8. Stopper 5
Includes an outlet 7 at the center thereof, and is fitted into one end opening of the casing 2 to restrict the valve body 3 and the coil spring 4 from falling off. The coil spring 4 includes a stopper 5 and a valve body 3.
Intervened between. Therefore, when the primary pressure of the liquid acts on the valve body 3 from the inlet 6 of the check valve 1, as shown in FIG. 2, the valve body 3 resists the urging force of the coil spring 4. By being separated from the valve seat 8, the flow of the liquid is allowed. When a secondary pressure due to liquid acts on the valve body 3 from the outlet 7 of the check valve 1, as shown in FIG. 1, the check valve 1 is operated based on the urging force of the coil spring 4 and the secondary pressure due to liquid. When the body 3 is pressed against the valve seat 8, the backflow of the liquid is prevented. In this embodiment,
A rubber valve seat 9 is attached to a portion of the valve body 3 pressed against the valve seat 8.

FIG. 4 is a front view of the valve body 3, FIG. 5 is a plan view of FIG. 4, and FIG. 6 is a bottom view of FIG. This valve element 3 guides the movement of the valve element 3 with respect to the valve seat 8,
It has a first guide slidable along the inner wall of the inlet 6. The check valve 1 of this embodiment has three central ribs 10 projecting upward as first guide portions. These central ribs 10 are arranged at equal angular intervals with respect to the center of the valve body 3. Further, the valve body 3 has a second guide portion slidable along the inner wall of the casing 2 to guide movement of the valve body 3 relative to the casing 2. The check valve 1 of this embodiment has a valve body 3 as a second guide.
And four outer peripheral ribs 11 protruding radially from the outer periphery at equal angular intervals. Each of the outer peripheral ribs 11 has a leg portion 12 extending downward along the moving direction of the valve element 3. The coil spring 4 is assembled so that one end of the coil spring 4 includes the legs 12 and engages with the outer peripheral ribs 11. The coil spring 4 is engaged with each of the outer peripheral ribs 11 at a position closer to the outside than the outer diameter of the valve seat 8, and the spring 4 presses the valve body 3 vertically against the valve seat 8. .

In this embodiment, as shown in FIG.
The outer surface 12a of each leg 12 is inclined toward the inside of the valve body 3 by a predetermined angle (for example, “1 °”). Each leg 12
Is long enough to secure the necessary flow path even if the coil spring 4 is compressed most.

As shown in FIGS. 1 and 2, the check valve 1 of this embodiment has a gap Ga between the outer periphery of the valve body 3 and the inner periphery of the coil spring 4 for permitting the passage of liquid. Having. As shown in FIGS. 4 and 6, the outer peripheral edge of the valve body 3 corresponding to the gap Ga is a tapered surface 13.

The two check valves 1 are arranged in series in the backflow preventer 73 of the connecting portion 64 of the bath water heater shown in FIG. FIG. 7 is a front view showing a specific configuration of the connecting portion 64 with a part thereof broken away. The connection portion 64 has a connection pipe 71, an on-off valve 72, a backflow prevention device 73, and a switching valve 74 connected in series to the connection pipe 71.

In this embodiment, the on-off valve 72 is composed of a pilot-type diaphragm valve driven by the solenoid 21. The first connection port 22 communicating with the on-off valve 72 is connected to a hot water supply pipe 67 of the hot water supply unit 62. The switching valve 74 is constituted by a ball valve driven by the motor 23, and its second and third connection ports 24 and 25 are connected to the circulation pipe 69 of the reheating unit 63, respectively. Therefore, in order to supply new hot water to the bathtub 61, the on-off valve 72 is opened,
The switching valve 74 is switched so that the first connection port 22 and the second or third connection ports 24 and 25 can communicate with each other. Thus, the hot water of the hot water supply unit 62 is dropped into the bathtub 61 via the connection unit 64 and the reheating unit 63. On the other hand, in order to reheat the hot and cold water in the bathtub 61, the switching valve 74 is switched so that the second and third connection ports 24 and 25 communicate with each other, and the circulation pump 68 is operated to exchange the hot and cold water in the bathtub 61 with heat. It is circulated through a circulation pipe 69 while being heated in a vessel 70.

The non-return valve 73 is arranged such that the two check valves 1 are stacked one on top of the other with the inlet 6 facing upward. The connection portion 64 of this embodiment further includes a flow sensor 26 arranged in series with the two check valves 1. This flow sensor 2
Reference numeral 6 denotes a rotary magnet Hall element for detecting the amount of hot water flowing through the connecting portion 64. The backflow prevention device 73 separates the hot water supply pipe 67 and the circulation pipe 69 by cooperation of the two check valves 1, and prevents hot water in the bathtub 61 from flowing back to the hot water supply pipe 6. The hot water supply apparatus of this embodiment automatically supplies new hot water to the bath tub 61 when the hot water in the bath tub 61 is low.
Control for keeping the water level of 1 constant is performed.

Next, the operation and the like of the check valve 1 constructed as described above and the bath water heater including the check valve 1 will be described.

In the bath hot water supply apparatus, in order to replenish the bathtub 61 with fresh hot water, the switching valve 74 is switched to connect the connection pipe 71 to the circulation pipe 69. At this time, due to the relationship between the water level of the bathtub 61 and the position of the check valve 73, the outlet 7 of the check valve 1 may be subjected to the secondary pressure due to the hot water in the bathtub 61. When there is a problem with the check valve 1 on the downstream side among the two check valves 1, a secondary pressure due to hot water may be applied to the outlet 7 of the check valve 1 on the upstream side. Here, when the water level of the bathtub 61 is sufficiently higher than the position of the check valve 1, the secondary pressure applied to those outlets 7 becomes sufficiently large. At this time, the check valve 1 has a coil spring 4
1 and the secondary pressure of the hot and cold water in the bathtub 61, a force for vertically pressing the valve body 3 vertically against the valve seat 8 acts, and as shown in FIG. Will be done. Alternatively, when the water level of the bathtub 61 is sufficiently lower than the positions of the two check valves 1, the pressure due to the hot water of the bathtub 61 is not applied to the outlets 7, and only the urging force of the coil spring 4 causes the outlet 7 in FIG. , The valve element 3 is pressed vertically against the valve seat 8. With such a function of the check valve 1, the hot and cold water in the bathtub 61 never flows back to the hot water supply unit 62 side.

On the other hand, when the water level in the bathtub 61 is substantially the same as the position of the two check valves 1, a slight pressure may be applied to the outlets 7 by the hot water in the bathtub 61. At this time,
The check valve 1 has a force acting to press the valve body 3 against the valve seat 8, but the force is not sufficiently strong. According to the configuration of the check valve 1, each central rib 10 provided on the valve body 3 slides along the inner wall of the inlet 6,
The movement of the valve body 3 with respect to the valve seat 8 is guided. Therefore, the portion of the valve body 3 close to the valve seat 8 that greatly affects the sealing performance, that is, the movement of the valve seat 9 is guided along the central axis of the inlet 6 by the plurality of central ribs 10. In addition, the movement of the valve body 3 with respect to the casing 2 is guided by the plurality of outer peripheral ribs 11 provided on the outer circumference of the valve body 3 sliding along the inner wall of the casing 2. Therefore,
The movement of the valve body 3 is controlled by the outer peripheral ribs 11 by the casing 2.
Will be guided along the central axis of. Thus, by cooperation of each central rib 10 and each peripheral rib 11,
The movement of the valve body 3 with respect to the valve seat 8 is guided with a stable posture.

Further, since the valve element 3 is urged by the coil spring 4 at a position closer to the outside than the outer diameter of the valve seat 8, the urging force of the coil spring 4 is applied via the valve element 3 to the valve seat 8. Will act evenly on the contact surface. Since the valve element 3 is pressed perpendicularly to the valve seat 8, all the forces acting on the valve element 3 to close the check valve 1 are effective as the force for pressing the valve element 3 against the valve seat 8. Will work.

Therefore, the check valve 1 is heated by the hot water in the bathtub 61.
Even when a slight pressure is applied to the outlet 7, the valve body 3 and the valve seat 8 can be precisely joined to ensure a sufficient sealing property. As a result, the dirty hot water in the bathtub 61 can be prevented from flowing back to the hot water supply unit 62 side through the check valve 1, and sanitary management of the hot water supply unit 62 can be properly performed.

According to the check valve 1 of this embodiment, since the rubber valve seat 9 provided on the valve body 3 is interposed between the check valve 1 and the valve seat 8, the check valve 1 The degree of adhesion is improved. Also in this sense, the valve element 3 when a slight pressure is applied to the outlet 7
And the valve seat 8 can be improved in sealing performance.

According to the check valve 1 of this embodiment, the gap Ga between the outer periphery of the valve body 3 and the inner periphery of the coil spring 4
Therefore, the passage of the hot water when the check valve 1 is opened is secured by the gap Ga. That is, as shown in FIG. 2, when the check valve 1 is fully opened, the valve body 3 has a shape in which each leg 12 thereof is bottomed on the stopper 5, and the coil spring 4 is in the most compressed state. For this reason, although it becomes difficult for the hot water to flow from the outer periphery of the coil spring 4 to the outlet 7, the hot water easily flows to the outlet 7 due to the gap Ga between the valve element 3 and the coil spring 4. Further, since the outer peripheral edge of the valve element 3 corresponding to the gap Ga forms the tapered surface 13, the flow path resistance in the gap Ga is reduced. Therefore, when new hot water is supplied from the hot water supply unit 62 to the bathtub 61, the hot water can flow smoothly in each check valve 1, and a relatively large flow rate can be secured.

According to the check valve 1 of this embodiment, since the coil spring 4 engages with the respective outer peripheral ribs 11 in such a manner as to enclose the respective leg portions 12, the connection between the respective leg portions 12 and the coil spring 4 is prevented. Due to the contact, the lateral displacement of the valve element 3 or the coil spring 4 is regulated. Also in this sense, the posture of the valve body 3 can be stably maintained. Here, since the outer surface 12a of each leg 12 is inclined,
The contact friction between each leg 12 and the coil spring 4 is reduced, and the relative movement between the valve body 3 and the coil spring 4 becomes smooth. In this sense, the operational responsiveness of the check valve 1 can be ensured.

It should be noted that the present invention is not limited to the above-described embodiment, and can be carried out as follows without departing from the spirit of the invention.

(1) In the above embodiment, the check valve of the present invention is embodied in the check valve 1 applied to the check valve 73 of the hot water supply device for a bath. It can also be embodied in a check valve applied to it or a check valve applied to gas equipment.

(2) In the above embodiment, the valve seat 9 is provided for the valve body 3. However, a valve seat is provided on the contact surface of the valve seat 8, or both the valve body 3 and the valve seat 8 are provided. A valve seat may be provided. Alternatively, the valve seat can be omitted.

(3) In the above embodiment, the outer peripheral edge of the valve body 3 corresponding to the gap Ga between the valve body 3 and the coil spring 4 is the tapered surface 13, but this tapered surface 13 is omitted. Can also.

(4) In the above embodiment, the outer peripheral rib 11
A leg 12, and an outer surface 12 a of the leg 12 is attached to the valve body 3.
Are inclined inward, but this inclination can be omitted. Alternatively, each leg 12 itself can be omitted.

[0041]

According to the first aspect of the present invention, in the check valve, the movement of the valve body with respect to the valve seat is controlled by the first guide provided on the valve body slidably along the inner wall of the inlet. The second guide portion provided on the outer periphery of the valve body slidably along the inner wall of the casing guides the movement of the valve body with respect to the casing. Furthermore, the valve body is pressed perpendicularly to the valve seat by a spring engaged with the valve body at a position closer to the outside than the outer diameter of the valve seat. Accordingly, the movement of the valve body with respect to the valve seat is guided with a stable posture by the cooperation of the first and second guide portions. In addition, the biasing force of the spring acts evenly on the contact surface of the valve seat via the valve body, and all the force acting on the valve body to close the check valve is effective as a force for pressing the valve body against the valve seat. To work. As a result, when a small pressure is applied to the outlet, sufficient sealing performance can be ensured, and the effect of preventing backflow of the fluid can be prevented.

According to the invention described in claim 2, according to claim 1
In the present invention, at least one of the portion of the valve body pressed against the valve seat and the valve seat is made of a rubber valve seat.
Therefore, the degree of close contact between the valve body and the valve seat is improved by the valve seat interposed between the valve body and the valve seat. As a result, claim 1
In addition to the effects of the invention, the effect that the sealing performance between the valve body and the valve seat can be further improved when a small pressure is applied to the outlet.

According to the invention described in claim 3, according to claim 1
Alternatively, in the configuration of the second aspect of the present invention, the first guide portion may include a plurality of central ribs, the second guide portion may include a plurality of outer peripheral ribs, and each outer peripheral rib may include a leg portion to include each leg portion. , A coil spring is engaged with each outer peripheral rib. Therefore, the movement of the valve body with respect to the valve seat is guided with a stable posture by the cooperation of each central rib and each peripheral rib. In addition, the urging force of the coil spring acts uniformly on the contact surface of the valve seat via the valve body, and all of the force acting on the valve body to close the check valve is a force for pressing the valve body against the valve seat. It works effectively. As a result, when a small pressure is applied to the outlet, sufficient sealing performance can be ensured, and an effect that the backflow of the fluid can be prevented beforehand is exhibited.

According to the invention described in claim 4, according to claim 3,
In the configuration of the present invention, a gap for allowing fluid to pass is provided between the outer periphery of the valve body and the inner periphery of the coil spring, and the outer peripheral edge of the valve body corresponding to the gap is a tapered surface.
Therefore, the flow path of the fluid when the check valve is opened is secured by the gap, and the flow path resistance in the gap is reduced. As a result, in addition to the effect of the third aspect of the invention, the fluid can flow smoothly at the check valve when the valve is opened, and a relatively large flow rate can be secured.

According to the invention described in claim 5, according to claim 3,
Alternatively, in the configuration of the invention of claim 4, the outer surface of each leg is inclined. Therefore, the contact friction between each leg and the coil spring is reduced, and the movement between the valve body and the coil spring becomes smooth. In this sense, in addition to the effect of the third or fourth aspect of the present invention, an effect that the operational responsiveness of the check valve can be ensured is exhibited.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a check valve according to one embodiment.

FIG. 2 is also a cross-sectional view showing a check valve.

FIG. 3 is an exploded sectional view showing the check valve.

FIG. 4 is a front view showing the valve element.

FIG. 5 is a plan view of FIG. 4;

FIG. 6 is a bottom view of FIG. 4;

FIG. 7 is a front view showing a connection part of the water heater in a partially broken manner.

FIG. 8 is a sectional view showing a conventional check valve.

FIG. 9 is a conceptual configuration diagram showing a conventional bath water heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Check valve 2 Casing 3 Valve body 4 Coil spring 6 Inlet 7 Outlet 8 Valve seat 9 Valve seat 10 Central rib (constituting a 1st guide part) 11 Outer peripheral rib (constituting a 2nd guide part) 12 Leg 12a Outer surface 13 Tapered surface Ga gap

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Nobuhiro Inaba 850 Horinouchi-cho, Kasugai-shi, Aichi FK-term in the Kasugai Works of KK (Reference) 3H058 AA03 BB02 BB03 BB14 CA05 CA06 CA31 CC02 CD05 EE02 EE12

Claims (5)

[Claims] 1. A tubular casing having an inlet and an outlet, a valve seat provided in the casing corresponding to the inlet, and a valve provided in the casing corresponding to the valve seat. And a spring for pressing the valve body against the valve seat. When fluid pressure acts on the valve body from the inlet, the valve body is moved from the valve seat against the urging force of the spring. Allowing the fluid to flow by being separated,
When the fluid pressure acts on the valve body from the outlet, the valve body is pressed against the valve seat based on the urging force of the spring and the fluid pressure, thereby preventing a backflow of the fluid. A first guide portion provided on the valve body for guiding movement of the valve body with respect to the valve seat, and slidable along an inner wall of the inlet; and the valve with respect to the casing. A second guide portion provided on an outer periphery of the valve body for guiding movement of the body and slidable along an inner wall of the casing; and a spring positioned closer to an outer side than an outer diameter of the valve seat. Wherein the valve body is engaged with the valve body at a position (2), and the valve body is pressed perpendicularly to the valve seat by a spring thereof. 2. The check valve according to claim 1, wherein at least one of a portion of the valve body pressed against the valve seat and the valve seat is a rubber valve seat. . 3. The check valve according to claim 1, wherein the first guide is a plurality of central ribs protruding from the valve body, and the second guide is provided. The part is a plurality of outer peripheral ribs protruding radially from the outer periphery of the valve body; each of the outer peripheral ribs has a leg extending along a moving direction of the valve body; and And a coil spring including the respective leg portions and engaging with the respective outer peripheral ribs. 4. The check valve according to claim 3, wherein a gap is provided between an outer periphery of the valve body and an inner periphery of the coil spring to allow passage of the fluid, and the gap corresponds to the gap. A check valve, wherein an outer peripheral edge of the valve body is a tapered surface. 5. The check valve according to claim 3, wherein an outer surface of each of the legs is inclined inward of the valve body.