JP2003232456A - Check valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent dust or the like caught in a check valve when flow of fluid passing the check valve is little, and eliminate leak from the check valve. <P>SOLUTION: In this check valve, a valve chest 6 is defined between a fluid inlet 2 and a fluid outlet 4, and a valve element 7 movable in a fluid flowing direction is provided in the valve chest 6. A valve element move promoting member 9 to promote move of the valve element 7 is provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a check valve for preventing backflow of fluid.

[0002]

2. Description of the Related Art In a device using a fluid, a number of check valves are often provided when controlling the flow of the fluid, particularly when preventing the backflow of the fluid. There are various types of check valves depending on their structures, such as a lift type, a swing type, and an in-line type. As these check valves, suitable ones are selected and used according to the conditions of equipment or piping used.

For example, a water supply pipe used for a water supply system of a boiler or the like is provided with a check valve for preventing backflow of the water supply and boiler boiler water. By the way, since the pressure of boiler can water is high and high, it is necessary to take thorough measures against the reverse flow of boiler can water from the viewpoint of safety and the heat resistant temperature of the pretreatment equipment. Therefore, conventionally, in order to prevent leak of the check valve, that is, backflow, it is performed to combine the various different types of check valves described above or to arrange a plurality of check valves in series.

Also, as for the material of the valve element that abuts the valve seat of each type of check valve, various kinds of materials are used to prevent backflow. For example, a so-called elastic seal such as a rubber seal may be used, or a so-called metal-to-metal (non-elastic member) seal commonly called a metal seal may be used.

In this case, the check valve having only the elastic seal has low withstand pressure and insufficient durability.
In the case of only the metal seal, there is a problem that small dust is caught between the valve seat and the valve body, so-called dust is caught, the sealing performance is easily deteriorated, and a backflow of the fluid is likely to occur. In addition, in the case of both of the above-mentioned seals,
When the flow rate of the fluid passing through the check valve is extremely small, an extremely small gap is formed between the valve seat and the valve body, and the fluid flows through this gap. Then, the gap becomes a so-called gap acting as a filter, and small dust or the like that has passed through the strainer provided on the upstream side of the check valve is attached to this gap.
When preventing backflow of fluid, it may cause leakage of fluid.

[0006]

The problem to be solved by the present invention is to prevent dust or the like from being caught in the check valve when the flow rate of the fluid passing through the check valve is small, and It is to eliminate the leakage of the stop valve.

[0007]

The present invention has been made to solve the above problems, and the invention according to claim 1 defines a valve chamber between a fluid inlet and a fluid outlet. A check valve having a valve body movable in the direction of fluid flow in the valve chamber is characterized by including a valve body movement promoting member for promoting movement of the valve body.

Further, the invention according to claim 2 is characterized in that a flow passage expanding portion is provided in the valve chamber.

BEST MODE FOR CARRYING OUT THE INVENTION Next, a first embodiment of the present invention will be described. As a preferred embodiment, the present invention can be applied to a check valve that shuts off a reverse flow of fluid.

The check valve defines a valve chamber by forming a space in a valve body having a fluid inlet and a fluid outlet, and the valve body moves in the fluid flow direction in the valve chamber. It is configured to be flexible.

The valve body is formed into a tubular shape by a non-elastic member such as metal or synthetic resin, and has a valve seat in the valve chamber that abuts against the valve body.

The valve body is, for example, a disc-shaped valve body, is fixed to a valve shaft that penetrates the valve body, and is configured as a so-called top-shaped valve body. The valve body is mounted in the valve chamber so as to be movable in the fluid flow direction integrally with the valve shaft.

The valve body promotes movement of the valve body when the valve body is pulled away from the valve seat, that is, when the fluid is passed and the fluid is supplied to the fluid outlet side. It has a member. The valve body movement promoting member is fixed to the side surface of the valve body that is not in contact with the valve seat in a state of being in close contact with the side surface. Here, the fixed portion of the valve body movement promoting member may be fixed to the valve shaft on the side of the valve body that does not come into contact with the valve seat, or adhered to the side surface of the valve body, depending on the implementation. It is also preferable to fix the valve shaft to the valve shaft in this state. The valve body movement promoting member is formed into a disc shape that is concentric with the valve body and has an outer diameter larger than its outer diameter.

Further, the valve body is configured to contact the valve seat by the urging force of the compression spring when the fluid does not flow, that is, when the supply of the fluid is stopped. Here, the compression spring may be omitted depending on the implementation. The valve body preferably has a disc shape, but it is also preferable that the side in contact with the valve seat has a conical shape. Further, the valve body is integrally formed by a disc-shaped first valve body formed of an elastic member and a disc-shaped second valve body formed of an inelastic member having a smaller diameter than the first valve body. It is also preferable to use the valve element configured as described above depending on the implementation.

The operation of the check valve having the above structure will be described. First, in this check valve, at the time of forward flow, that is, when the fluid is supplied to the fluid outlet side, the valve body compresses toward the fluid outlet side based on the fluid pressure of the fluid flowing from the fluid inlet side. The fluid moves against the biasing force of the spring, and the fluid flows out to the fluid outlet side. That is, by moving the valve body, the contact between the valve body and the valve seat is released, the fluid passes through the gap between the outer periphery of the valve seat and the valve body,
Fluid exits the fluid outlet. On the other hand, when the inflow of the fluid from the fluid inlet is stopped, that is, when the backflow is prevented, the compression spring returns, and the valve body moves toward the fluid inlet due to the urging force of the compression spring. It abuts the valve seat and closes the gap. Therefore, backflow of the fluid from the fluid outlet side is prevented.

Here, it will be described in detail that the valve body movement promoting member operates efficiently when the supply amount of the fluid is small. When the supply amount of the fluid is small, the valve body movement promoting member has an outer diameter larger than the outer diameter of the valve body, and therefore the water flow resistance of the fluid flowing from the fluid inlet is large. When this water flow resistance is large, the pressure received by the valve body movement promoting member becomes large. Therefore, the valve body moves more toward the fluid outlet side against the biasing force of the compression spring, and the contact between the valve body and the valve seat is released with a larger gap. Here, it is preferable that the valve body is moved so that a gap larger than the size of the mesh of the strainer provided on the upstream side of the check valve is formed in the movement amount of the valve body. The amount of movement is determined based on the distance between the outer peripheral surface of the valve body movement promoting member and the inner wall of the valve chamber. As a result, according to the first embodiment, dust and the like pass without adhering to the gap between the valve seat and the valve body, so that contact between the valve body and the valve seat occurs. The surface is kept clean and does not cause leakage when preventing backflow.

Next, a second embodiment of the present invention will be described. The second embodiment is a modification of the first embodiment, and in the check valve of the first embodiment, the valve chamber on the fluid outlet side of the valve body movement promoting member is provided. Further, a flow channel expanding portion is further provided.

In the valve chamber, the flow passage expanding portion is
The inner diameter of the inner wall of the valve body movement promoting member on the fluid outlet side is increased to increase the fluid passage cross-sectional area. That is, the inner diameter of the inner wall is larger than the outer diameter of the valve body movement promoting member.

The operation of the flow channel expanding portion will be described.
The check valve according to the second embodiment is configured such that, at the start of water flow when the flow rate is low, the flow resistance is increased by the action of the valve body movement promoting member, that is, the flow rate is reduced. The amount of movement of the valve element is secured. After the movement amount of the valve element is secured, a predetermined flow rate is passed, so that the state in which the water passage resistance is increased is canceled by the action of the flow path expanding portion. That is, the distance between the outer peripheral surface of the valve body movement promoting member and the inner wall of the valve chamber is increased by the flow passage expanding portion. Therefore, since the fluid has a low water resistance by passing through the flow channel expanding portion,
The fluid flows to the fluid outlet side more than when the flow rate is reduced. As a result, according to the second embodiment, it is possible to prevent dust from being caught when the flow rate is low, and
It can be a check valve with low water resistance.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described in detail below with reference to the drawings. As a preferred embodiment, an in-line type check valve will be described. FIG. 1 is a cross-sectional explanatory view schematically showing the structure of the check valve, showing a state in which the flow path is open.

In FIG. 1, the check valve 1 comprises a valve chamber 6 defined by a valve body 3 having a tubular fluid inlet 2 and a lid member 5 having a tubular fluid outlet 4. There is. In the valve chamber 6, a valve body 7 is arranged so as to be movable, and a valve seat 8 that abuts the valve body 7 is provided. When the valve body 7 is separated from the valve seat 8, the valve body 7 is
That is, a valve body movement promoting member 9 that promotes the movement of the valve body 7 when the fluid is supplied to the fluid outlet 4 side is provided. Further, the check valve 1 includes the valve body 7 and the valve seat 8
A compression spring 10 is provided for abutting against.

In the flow path from the fluid inlet 2 to the fluid outlet 4, the valve body 3 has a circular opening 11 which is orthogonal to the flow path. The opening 11 is surrounded by the lid member. It is provided with a main body connecting portion 12 that is joined to the unit 5. The main body connecting portion 12 and the lid connecting portion 13 provided on the lid member 5
The valve chamber 6 is defined by screwing and. The valve seat 8 that contacts the valve body 7 is formed around the opening 11. The valve seat 8 is
It is formed on the outlet side of the valve body 3.

In the valve chamber 6, the valve body 7 abuts the valve seat 8 to close the opening 11.
It is arranged so as to be movable in a direction orthogonal to the opening 11. Then, the valve body movement promoting member 9 is
A side surface of the valve body 7 that does not come into contact with the valve seat 8 (reference numeral omitted)
It is fixed to the valve shaft 14 in a state where a part of it is in close contact with the valve shaft 14.
The valve body movement promoting member 9 is formed in a disk shape concentric with the valve body 7 and having an outer diameter larger than the outer diameter thereof.

The valve body 7 will be described in detail with reference to FIG. FIG. 2 is an exploded perspective view for explaining components arranged in the valve chamber 6.

The valve body 7 is a disc-shaped first valve body 15 made of an elastic member, and a disc-shaped second valve body made of an inelastic member having a smaller diameter than the first valve body 15. 16
It is composed of and. The two valve bodies 15 and 16 are fixed to the valve shaft 14 so as to be an integral valve body in a state of being in close contact with each other, and are configured as so-called top-shaped valve bodies. Here, the valve body 7 has the valve body movement promoting member 9 on the side surface (reference numeral omitted) of the first valve body 15.
It is equipped with a part of it in close contact. The valve body 7 is mounted in the valve chamber 6 so as to be movable in the fluid flow direction integrally with the valve body movement promoting member 9 and the valve shaft 14.

Here, each of these members will be described in more detail. The first valve body 15 is formed by press-molding rubber or the like, which is an elastic material, and is provided with a sleeve portion 17 integrally formed at the center thereof so as to project toward the fluid inlet 2 side. Mounting hole 1 including
Eight. Here, the protruding length of the sleeve portion 17 is formed to be slightly longer than the plate thickness of the second valve body 16. The wall thickness of the sleeve portion 17 is set to an appropriate thickness so that the sleeve portion 17 is elastically deformed in fitting with the second valve body 16 to exert an effect on tight fitting. . The inner diameter of the mounting hole 18 is formed to be slightly smaller than the outer diameter of the mounting portion (the inlet side shaft portion 22 described later) of the valve shaft 14 in order to tightly fit the valve shaft 14.

The first valve body 15 has a portion (that is, a shoulder portion on one side of the first valve body 15) that abuts against a contact surface of the valve seat 8 (first valve seat 19 described later). Chamfering is performed to form the conical first seal portion 20. Further, in the first valve body 15, a recess 21 for arranging one end of the valve body movement promoting member 9 and the compression spring 10 is integrally formed in the central portion of the fluid outlet 4.

The second valve body 16 is made by pressing metal or the like, which is an inelastic material, and is in contact with a contact surface of the valve seat 8 (a second valve seat 23 described later) (ie, a portion). A flat plate-shaped second seal portion 24 is formed on one surface of the second valve body 16. A fitting hole 25 is provided at the center of the second valve body 16 for tightly fitting the outer peripheral surface of the sleeve portion 17.

The valve body movement promoting member 9 is formed in a disk shape concentric with the valve body 7 and having an outer diameter larger than the outer diameter of the first valve body 15. put it here,
The outer diameter of the valve body movement promoting member 9 is
It is determined so as to have a predetermined water flow resistance. That is, the outer diameter dimension is such that the distance between the outer peripheral surface 26 of the valve body movement promoting member 9 and the inner wall (the reference numeral is omitted) of the valve chamber 6 is a distance that provides a predetermined water resistance when the fluid flows. Is determined as
Further, the valve body movement promoting member 9 is provided with a convex portion 27 which is in close contact with the concave portion 21 and a second fitting hole 28 which is fitted with the inlet side shaft portion 22 in the central portion thereof.

Next, the valve shaft 14 is arranged in the valve chamber 6 with both ends thereof being supported by an inlet guide 29 and an outlet guide 30, respectively. The valve shaft 14
Is formed in a two-stage rod shape with a thick central portion, and has a small diameter inlet side for fixing both valve bodies 15 and 16 and the valve body movement promoting member 9 with a push nut 31 and for penetrating the inlet guide 29. The shaft portion 22 and the valve bodies 15 and 1
6 and a central shaft portion 32 that serves as a guide for fixing the valve body movement promoting member 9 on the outlet side and the compression spring 10, and a small-diameter outlet side shaft portion 33 for penetrating the outlet guide 30. ing.

Further, the push nut 31 is provided with a fixing hole 34 at the center thereof, and the periphery of the fixing hole 34 is a fixing member composed of a leaf spring (reference numeral omitted) having elastic force. With the push nut 31, both valve bodies 1
5, 16 and the valve body movement promoting member 9 are fixed to the valve shaft 14.

Here, the assembly of the valve body 7 will be described. The valve body 7 includes the valve shaft 14, the valve body movement promoting member 9, the first valve body 15, the second valve body 16 and the valve body 7. It is integrally assembled by the push nut 31.

Next, a procedure for assembling the valve body 7 will be described. First, the valve body movement promoting member 9 is fitted into the inlet side shaft portion 22 through the second fitting hole 28, and then the first valve body 15 is fitted through the mounting hole 18. Further, the second valve body 16 is fitted into the sleeve portion 17 through the fitting hole 25. Then, by fitting the push nut 31 into the inlet side shaft portion 22 through the fixing hole 34, the valve body movement promoting member 9 and the both valve bodies 15 and 16 are attached to the end surface of the central shaft portion 32. It is pressed against 35, sandwiched and fixed. The push nut 31 is
By the force of the leaf spring, the valve body movement promoting member 9 and the both valve bodies 15, 16 are fixed to the inlet side shaft portion 22 without returning, and by the force of the leaf spring.
Continue pressing to 5. As a result, the valve body 7 is assembled into a valve body having a so-called top shape, and with the compression spring 10 arranged on the outer periphery of the central shaft portion 32, the valve chamber 6 is moved by the guides 29 and 30. Placed inside.

The prevention of fluid leakage from the valve shaft 14 of the first valve body 15 and the second valve body 16 will be described in detail. By inserting the inlet-side shaft portion 22 into the mounting hole 18, the fluid is leaked and fixed. On the other hand, by mounting the second valve body 16 on the sleeve portion 17 via the fitting hole 25, the first valve body 15 and the second valve body 16 are configured as an integral valve body. Since it is fixed to the valve shaft 14 as this integral valve body, no fluid leaks from the valve shaft 14.

Next, the inlet guide 29 is formed in a three-pronged shape, and fluid can pass through the three gaps 36 of the three-pronged part. Further, the inlet guide 29 is provided with an inlet-side bearing portion 37 in the central portion of the inlet guide 29 in order to hold the valve body 7 in the central portion of the flow path. Then, three claw portions 38 are provided on the peripheral portion thereof.

The outlet guide 30 is the inlet guide 2
Similar to No. 9, it is formed in a three-pronged shape, and fluid can pass through the three gaps 36 of the three-pronged. Further, the outlet guide 30 is provided with an outlet side bearing portion 39 in the center portion of the outlet guide 30 in order to hold the valve body 7 in the center portion of the flow path. Further, the claw portions 38 are provided at three places on the peripheral portion thereof.

Next, the valve seat 8 will be described with reference to FIG. 1. The valve seat 8 contacts the first valve seat 19 that abuts the first valve body 15, the second valve body 16 and the second valve body 16. The second valve seat 23 is in contact with the second valve seat 23. Here, the first valve seat 19 and the second valve seat 23 have the opening 11
And the first valve seat 19 is formed around
It is formed on the outer peripheral side of the second valve seat 23 and on the downstream side of the second valve seat 23. The shape of the first valve seat 19 is formed so as to have a predetermined angle with respect to the valve shaft 14 so as to have a so-called mortar-shaped contact surface. The contact surface of the second valve seat 23 is formed so as to be orthogonal to the axial direction of the valve shaft 14.

The valve body 7 formed by the guides 29 and 30.
The support and assembly of the check valve 1 will be described in detail with reference to FIGS. 1 and 2. First, in the valve body 3, the claw portions 38 of the inlet guide 29 are fitted into and fixed to the inlet side groove portions 40 provided on the inner peripheral surface of the fluid inlet 2. Next, the valve body 7 is arranged in the valve chamber 6 in a state where the second valve body 16 is on the fluid inlet 2 side, and the inlet side shaft portion 22 penetrates the inlet side bearing portion 37. Then, the compression spring 10 is attached to the central shaft portion 32.
Place it on the outer circumference.

Next, in the lid member 5, each claw portion 38 of the outlet guide 30 is fitted and fixed in the outlet side groove portion 41 provided in the fluid outlet 4. Then, in this fixed state, the packing 42 is attached to the lid connecting portion 13.
Is sandwiched and screwed with the main body connecting portion 12, so that the outlet side shaft portion 33 penetrates the outlet side bearing portion 39. As a result, the valve body 3 and the lid member 5 are joined together, and the check valve 1 is completely assembled. Here, the valve body 7 can move in the flow direction of the fluid, that is, to the fluid outlet 4 side when the fluid is supplied, and to the fluid inlet 2 side when the fluid supply is stopped. The movable range is restricted by the arrangement of the guides 29 and 30.

Next, the operation of the check valve 1 having the above construction will be described. Here, a case where the fluid is water will be described. At the time of water supply, the valve body 7 is provided with the fluid inlet 2
Based on the water pressure of the feed water flowing in from the compression spring 10
Against the biasing force of the fluid outlet 4 side, the contact between the valve body 7 and the valve seat 8 is released (state of FIG. 1),
Water flows out to the fluid outlet 4 side. That is, by moving the valve body 7, the valve body 7 and the both valve seats 1
The contact with 9, 23 is released, water passes through the gap on the outer circumference of the valve body 7, and the passed water flows out from the fluid outlet 4. Here, the movement of the valve element 7 is performed by the valve shaft 1
Since 4 is supported by both of the guides 29 and 30, it is possible to smoothly move in the flow direction of water, that is, in both forward and reverse directions.

On the other hand, the case of preventing the backflow of the flow path when the water supply is stopped will be described with reference to FIG.
FIG. 3 is a schematic explanatory view showing a stage in which the valve body 7 comes into complete contact with the valve seat 8. In FIG. 3, the second valve body 16 contacts the second valve seat 23. At this time, the first valve body 15 is elastically deformed, and the first seal portion 20 is in close contact with the first valve seat 19. The second seal portion 24 is in close contact with the second valve seat 23. That is, the valve body 7 is operated by the compression spring 10 and when the pressure on the fluid outlet 4 side is higher than that on the fluid inlet 2 side,
Due to the pressure difference, the valve seats 19 and 23 are pressed against each other, and the backflow of the feed water from the fluid outlet 4 side is prevented. As a result, the flow path is doubly blocked by the first valve body 15 and the second valve body 16. Therefore, backflow of water to the fluid inlet 2 side is prevented.

Here, the leakage from the valve shaft 14 is first caused by the end surface 35 of the recess 21 and the first valve body 1.
5 is blocked by the contact with 5, and further the inlet side shaft portion 22
It is completely ensured by the sealing effect due to the elastic action of the sleeve portion 17 mounted on.

Now, the characteristic operation of the present invention will be described. This invention, when the water supply is small,
The valve body movement promoting member 9 operates efficiently, which will be described in detail below with reference to FIG. FIG. 4 shows the valve body 7
Is a schematic explanatory view showing a stage slightly separated from the valve seat 8, that is, a case where the valve body 7 slightly moves toward the fluid outlet 4 side when the flow rate is small. In FIG. 4, by this movement, first, the second valve body 16 arranged on the fluid inlet 2 side is separated from the second valve seat 23. Next, the first valve body 15 separates from the first valve seat 19. At this time, since the valve body movement promoting member 9 has an outer diameter larger than the outer diameter of the valve body 7, a gap (reference numeral omitted) between the valve body 6 and the inner wall of the valve chamber 6 is narrow.
The water flow resistance of the water flowing in from is large. When this water flow resistance is large, the pressure received by the valve body movement promoting member 9 becomes large. Therefore, the valve body 7 is moved more toward the fluid outlet 4 side against the biasing force of the compression spring 10 in consideration of the action of the valve body movement promoting member 9.
The contact between the valve body 7 and the valve seats 19 and 23 is released with a larger gap. Here, the valve body 7
The valve body 7 is moved so that a gap larger than the mesh size of a strainer (not shown) provided on the upstream side of the check valve 1 is formed.

As described above, according to this first embodiment,
Since dust and the like pass through the gap between the valve seat 8 and the valve body 7 without adhering to it, the contact surface is kept clean, and when leaking back water, the cause of leakage is I won't.

The structure of a modification of the first embodiment will be described with reference to FIG. In this modification, a flow passage expanding portion 43 is further provided in the valve chamber 6 on the fluid outlet 4 side of the valve body movement promoting member 9. The flow path expanding portion 43 is provided in the valve chamber 6 as follows.
The inner diameter of the inner wall of the valve body movement promoting member 9 on the fluid outlet 4 side is increased to increase the fluid passage cross-sectional area. That is, the inner diameter of the inner wall is larger than the outer diameter of the valve body movement promoting member 9. Therefore, at the time of normal flow of the fluid, the outer peripheral surface 26 and the inner wall are configured to be able to maintain an enlarged distance.

The operation of the flow channel expanding section 43 will be described with reference to FIGS. 4 and 1. Also in this modification,
The case where the fluid is water will be described. First, as shown in FIG. 4, in the check valve 1, when the water flow is started when the flow rate is small, the water resistance is increased by the action of the valve body movement promoting member 9, that is, the flow rate is reduced. The amount of movement of the valve body 7 is secured in this state. Next, after the movement amount of the valve body 7 is secured, the state shown in FIG. 1 is established, and in order to pass a predetermined flow rate, by the action of the flow path expanding section 43,
The state in which the water resistance is increased is canceled. That is,
The flow path expanding portion 43 increases the distance between the outer peripheral surface 26 of the valve body movement promoting member 9 and the inner wall.
Therefore, the water passes through the flow path expanding portion 43, so that the water flow resistance is reduced, so that the water flows to the fluid outlet 4 side more than when the flow rate is reduced.

As described above, according to this modification, dust can be prevented from being caught when the flow rate is small, and
It can be a check valve with low water resistance.

[0047]

According to the present invention, when the flow rate of the fluid passing through the check valve is small, it is possible to prevent dust or the like from being caught in the check valve and prevent the check valve from leaking. .

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view schematically showing the structure of a check valve when a flow path is open.

FIG. 2 is an exploded perspective view for explaining components of a valve body arranged in the valve chamber of the check valve.

FIG. 3 is a schematic explanatory diagram showing a stage when a fluid supply is stopped.

FIG. 4 is a schematic explanatory view showing a stage where the valve body of the check valve is slightly separated from the valve seat.

[Explanation of symbols]

2 fluid inlet 3 Fluid outlet 6 valve chambers 7 valve body 9 Valve body movement promotion member 43 Channel expansion part

Claims (2)

[Claims] 1. A check valve comprising a valve chamber (6) defined between a fluid inlet (2) and a fluid outlet (4), and a valve body (7) movable in the fluid flowing direction in the valve chamber (6), wherein the valve is a valve. A check valve comprising a valve body movement promoting member 9 for promoting movement of the body 7. 2. The check valve according to claim 1, wherein a flow passage expanding portion 43 is provided in the valve chamber 6.