JPH10132111A - Ball check valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely close a passage even in a ball valve element made of plastic having a relatively lower spherical accuracy. SOLUTION: A cylindrical valve seat body 4 formed of a relatively flexible material and having an inner peripheral surface smaller than that of a ball valve element 3 is projected on an opening periphery of an introduction hole 10 for fluid which opens on a valve chamber 2 within a casing 1. When the ball valve element 3 pressed by fluid flowed back from an introduction hole 12 side is fitted in the valve seat body 4 to deform so as to enlarge a diameter, the valve seat body 4 is deformed a shape corresponding to a surface shape of the ball valve element 3, whereby the inner peripheral surface of the valve seat body 4 and a surface of the ball valve element 3 are closely brought into contact with each other. Accordingly, a passage can be surely closed even in the case where a spherical accuracy of the ball valve element is relatively low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball check valve.

[0002]

2. Description of the Related Art A ball valve body accommodated in a valve chamber in a case body comes into contact with a valve seat surface provided at an opening edge of an inflow hole of a fluid into the valve chamber to close a flow path, thereby causing a backflow. Ball check valves adapted to be restrained are known. In this ball check valve, the ball valve body is separated from the valve seat by being pushed by the forward flow, and the fluid passes through the gap between the ball valve body and the inner surface of the valve chamber. It has the advantages of small size and smooth opening and closing operation, and is used in various fields.

[0003]

However, since the ball valve element freely rolls in the valve chamber when the valve is opened, the flow path can be securely closed by being in close contact with the predetermined valve seat surface from any angular position. Thus, high accuracy is required for the spherical surface of the ball valve element.
For this reason, the ball valve element is generally made of a metal such as steel that can be processed into a highly accurate spherical surface. However, since physical and chemical instruments handling various chemicals cause a problem of corrosion, expensive precious stones such as sapphire having excellent chemical resistance may be used, and there has been a problem that the production cost increases. On the other hand, it is conceivable to use a chemically stable plastic material for the ball valve body.However, since it is troublesome to provide a spherical surface with a plastic material, it is possible to ensure sufficient sealing performance. Therefore, it was difficult to achieve both a reduction in manufacturing cost and chemical resistance.

[0004]

SUMMARY OF THE INVENTION In order to solve such a problem, the present invention provides a structure in which a flow path can be reliably closed even with a plastic ball valve having relatively low spherical accuracy. Is a ball check valve in which the inflow hole of the fluid opened to the valve chamber inside the case body is closed by a ball valve body to prevent the backflow of the fluid from the outflow hole side. An expandable and deformable cylindrical valve seat body made of a relatively flexible material having a small diameter inner peripheral surface is protrudingly provided at an opening edge of the inflow hole, and urges the fluid pressure in a reverse flow direction. The formed ball valve body fits inside the valve seat body and expands the diameter of the valve seat body while pressing against the inner peripheral surface of the valve seat body to close the flow path. Thereby, when the ball valve body urged by the fluid pressure in the reverse flow direction presses against the valve seat body to expand and deform the valve seat body, the valve seat body is shaped into a shape corresponding to the surface shape of the ball valve body. Since it is appropriately deformed, the inner peripheral surface of the valve seat body and the surface of the ball valve body come into close contact with each other. For this reason, even when the spherical accuracy of the ball valve element is relatively low, the flow path can be reliably closed.

In particular, the inflow hole is provided at one end of the case body and the outflow hole is provided at the other end side of the case body. In an initial state, the ball valve body is provided with the valve seat body and the outflow hole. It is good to be clamped between the opening edge of the hole. As a result, the valve state immediately shifts from the initial state in which the pressures on both sides are equal to the fully closed state in which the valve seat body and the ball valve body are in close contact with each other due to the fluid pressure in the reverse flow direction, thereby reducing the time lag at the time of the check. Can be. However, if the valve seat body is arranged vertically below the ball valve body, the ball valve body is kept in contact with the valve seat body by its own weight in the initial state, so that the same effect as above can be obtained. However, with the above configuration, the time lag at the time of the non-return check can be reduced in both the vertical and horizontal arrangements.
On the other hand, with respect to the flow in the forward direction, the fluid flows through the gap formed between the valve seat body and the ball valve body due to the expansion of the valve seat body due to the pressure on the primary side. Can be passed smoothly.

Further, it is preferable that the valve seat body is formed in a mortar shape whose opening side is enlarged in diameter. Thus, the ball valve body can be stably supported by the inner peripheral surface of the valve seat body. In addition, when the ball valve body is pressed against the valve seat body by being pushed by the flow in the opposite direction, the diameter expansion of the valve seat body and the movement of the ball valve body are performed smoothly. Since a large deformation is not generated in the seat body, the seat body can have high durability.

It is preferable to provide a plurality of guide pieces extending in the axial direction with a predetermined gap in the circumferential direction so as to surround the ball valve body from the end of the valve seat body. Thereby, since the guide piece moderately regulates the ball valve body to swing greatly in the direction perpendicular to the axis of the valve seat body due to the flow in the forward direction, the ball valve body is quickly returned to the initial position, The time lag of the closing operation can be reduced. The same effect can be achieved by separately providing a guide member in the valve chamber. However, by integrally providing the guide member with the valve seat, the structure is simplified, and the manufacturing cost can be reduced. it can. On the other hand, with respect to the flow in the forward direction, the fluid flows smoothly through the gap between the guide pieces, and therefore does not hinder the flow of the fluid.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below based on embodiments shown in the accompanying drawings.

FIG. 1 shows a ball check valve according to a first embodiment of the present invention. The ball check valve includes a case 1 having a substantially cylindrical shape,
A ball valve body 3 housed in a valve chamber 2 formed at an intermediate portion in the axial direction of the valve body, and a valve comprising a mortar-shaped valve seat body 4 forming one wall of the valve chamber 2 and protruding into the valve chamber 2 A seat plate 5 and a support plate 6 provided in contact with the valve seat plate 5;
All of these members are formed of a plastic material, and are suitable for a liquid sending circuit of a physicochemical apparatus such as a liquid chromatography for analyzing a test solution.

The case body 1 is made of a tough plastic material having excellent chemical resistance, for example, PEEK (polyetheretherketone) resin, and screw-type joints 7, 8 are provided at both ends in the axial direction. It is provided, and the liquid sending pipe is connected via a predetermined joint. Further, a partition wall 9 is integrally provided at the axial center side of the right joint portion 8 in the drawing, and the partition wall 9 and the joint portion 7 on the left side in the drawing are opposed thereto. The valve chamber 2 is defined between the opening and the valve seat plate 5 inserted.

The valve seat plate 5 is integrally formed of a relatively soft plastic material, for example, a fluororesin. This fluororesin has the property of being non-adhesive and having a small coefficient of friction. For this reason, the ball valve 3 is attached to the valve seat 4.
As described later, the ball valve element and the valve seat element are quickly separated from each other as the pressure on the primary side increases. In addition, fluororesins are excellent in chemical resistance, and thus are advantageous when applied to physical and chemical instruments that handle various chemical solutions. Further, the valve seat body 4 is connected to the valve seat plate 5.
In addition to reducing the number of parts, assembling is facilitated, and the valve seat body 4 can be accurately arranged in the valve chamber 2.

On the side of the valve seat plate 5 opposite to the valve chamber 2,
A support plate 6 for substantially supporting the internal pressure of the valve chamber 2 acting on the valve seat plate 5 is inserted. This support plate 6
It is formed of a material having higher rigidity than the valve seat plate 5, for example, the same PEEK resin as the case body 1, and is fixed to the case body 1 by press fitting. As described above, the valve seat body 4 is
When formed integrally, the valve seat plate 5 is also formed of a flexible plastic material, so that the rigidity tends to be insufficient with respect to the internal pressure of the valve chamber 2. However, the support plate 6 is provided in this manner. By reinforce | reinforcement, rigidity shortage is eliminated and it can be set as the strong structure which can endure the internal pressure of the valve room 2.

As will be described later, this ball check valve allows liquid to flow only in the forward flow from the left to the right in the figure, and is arranged along the axis of the case body 1.
Inflow holes 10 and 11 for introducing liquid into the valve chamber 2 are provided at the center of the valve seat plate 5 and the support plate 6, and are provided at the center of the partition wall 9 for discharging the liquid in the valve chamber 2. Outflow holes 12 are respectively provided.

The valve seat 4 has a conical shape centered on the axis of the case body 1 and extends from the peripheral edge of the opening of the inflow hole 10. In the initial state shown in FIG. 1, that is, when not in use or when the pressure on the primary side and the pressure on the secondary side are equal, the surface of the ball valve body 3 on the side opposite to the valve seat body 4 is
The ball valve body 3 is in contact with the inner peripheral surface of the valve seat body 4 from the slightly distal end so that the ball valve body 3 substantially closes the opening of the valve seat body 4. Is held at a position substantially aligned with the axis of the case body 1.

If the outlet hole 12 is provided coaxially with the valve seat body 4 in the partition wall 9 against which the ball valve body 3 abuts, the fluid pressure flowing backward from the outlet hole 12 can be reduced. The ball valve element 3 can be uniformly acted on a surface opposite to the valve seat element 4 in a direction in which the ball valve element 3 is displaced along the axial direction of the valve seat element 4. For this reason, the ball valve body 3 is displaced substantially linearly along the axial direction of the valve seat body 4 without largely swinging, and quickly reaches a predetermined fully closed state in which the ball valve body 3 is pressed against the valve seat body 4 described later. And the time lag at the time of non-return can be shortened.

As shown in FIG. 2, a plurality of notched grooves 13 having a V-shaped cross section are provided at the opening edge of the outflow hole 12 where the ball valve element 3 is stopped. The valve chamber 2 and the outflow hole 12 communicate with each other even when the ball valve body 3 is in contact with the opening edge of the outflow hole 12. For this reason, as described later, at the time of normal flow, the flow path is not closed, and the fluid can flow from the valve chamber 2 to the outflow hole 12 through the notch groove 13. In addition,
The cut-out groove 13 is not limited to the above-described shape, and may be appropriately formed in a shape having a required cross-sectional area and suitable for appropriately passing a fluid.

In the ball check valve constructed as described above, the pressure on the inflow holes 10 and 11 (primary side) on the left side in the figure is compared with the pressure on the outflow hole 12 (secondary side) on the right side in the figure. When the liquid tries to flow in the opposite direction,
As shown in (A), the ball valve body 3 is pressed against the valve seat body 4 by the differential pressure between the primary side and the secondary side, and while the diameter of the valve seat body 4 expands and deforms, the ball valve body 3 moves along the axis. Move left. At this time, the valve seat body 4 is deformed corresponding to the surface shape of the ball valve body 3, and the inner peripheral surface of the valve seat body 4 comes into close contact with the surface of the ball valve body 3, so that the flow path is securely closed. Is done. In addition, both the inner peripheral surface of the valve seat body 4 and the surface of the ball valve body 3
By forming the surface smoothly by mirror finishing, the adhesion between the valve seat body 4 and the ball valve body 3 is enhanced.

On the other hand, when the pressure on the primary side is higher than that on the secondary side, that is, when the liquid is going to flow in the positive direction, 1
The pressure on the next side acts on the inner peripheral surface of the valve seat body 4, and as shown in FIG. A gap is formed between the surface and the inner peripheral surface of the valve seat body 4, and through this gap, as shown by arrows in FIG. Is introduced into the outlet hole 12.

At this time, if the valve seat body 4 is formed of a fluororesin, the ball valve body 3 does not seize on the valve seat body 4 and responds to the differential pressure acting on the ball valve body 3. As a result, the ball valve element 3 and the valve seat element 4 are immediately separated from each other, and the flow path is opened.

FIG. 4 shows a ball check valve according to a second embodiment of the present invention. This ball check valve is the same as the mortar-shaped valve seat body 4 shown in the first embodiment.
A straight cylindrical valve seat body 2 instead of the valve seat plate 5 provided with
1 and a valve seat plate 23 provided with a plurality of guide pieces 22 extending in the axial direction from the end of the valve seat body. Other parts are the same as in the first embodiment,
The same reference numerals are given and the detailed description is omitted.

The inner peripheral surface of the valve seat body 21 is formed to have a smaller diameter than the ball valve body 3, and the inner peripheral side of its end face is chamfered in an arc shape, and the other side is a partition wall portion. The ball valve body 3 abutted against the opening edge of the outflow hole 9 of the nozzle 9 comes into contact with the ball valve body 3 and is held on the axis of the case body 1. As shown in FIG. 5, the guide pieces 22 are arranged in a row in the circumferential direction so as to surround the ball valve element 3 with a gap having substantially the same size as the circumferential width of the guide pieces 22. .

In the ball check valve thus configured, the pressure on the primary side on the left side in the figure is lower than that on the secondary side on the right side in the figure, that is, whether the liquid flows in the opposite direction. Then, the state in which the ball valve body 3 urged by the differential pressure between the primary side and the secondary side comes into contact with the front end of the chamfered valve seat body 21 is shown in FIG. As described above, while the opening of the valve seat body 21 is expanded and deformed, it moves to the left in the axial direction and smoothly enters the inside of the valve seat body 21. Thereby, the inner peripheral surface of the valve seat 21 deformed according to the surface shape of the ball valve body 3 and the surface of the ball valve body 3 are brought into close contact with each other, and the flow path is securely closed.

On the other hand, when the pressure on the primary side is higher than that on the secondary side, that is, when the liquid tries to flow in the forward direction, as shown in FIG. The valve seat 21 is expanded in diameter by being pressed by the pressure on the next side, and a gap is formed between the surface of the ball valve body 3 abutted against the partition 9 and the inner peripheral surface of the valve seat 21. As shown by arrows in FIG. 6B, the liquid introduced from the inflow holes 11 and 10 into the valve seat 21 through the gap is sent to the outflow hole 12. At this time, the guide piece 22 restricts the ball valve 3 from largely moving up and down.

The ball valve body 3 is desirably formed of a fluororesin similarly to the valve seat plates 5 and 23 in order to prevent the ball valve body 3 from galling on the valve seat bodies 4 and 21. The support plate 6
May be fixed to the case body 1 by screwing.

[0025]

As described above, according to the present invention, when the ball valve body urged by the fluid pressure in the reverse flow direction is fitted while expanding the diameter of the valve seat body, the valve seat body is fitted with the ball valve body. It is deformed appropriately according to the surface shape, and the inner peripheral surface of the valve seat body and the surface of the ball valve body come into close contact, so even if the accuracy of the spherical surface of the ball valve body is relatively low, the flow path is securely closed can do. Therefore, it is possible to use a plastic ball valve having low spherical precision, and to provide a ball check valve excellent in chemical resistance at low cost. Further, since a highly accurate spherical surface is not required for the ball valve body, there is an advantage that the manufacturing cost is reduced even when the ball valve body is formed of a material other than a plastic material.

In particular, in the initial state, if the ball valve element is sandwiched between the valve seat body and the opening edge of the outflow hole, the vertical state and the horizontal state will change from the initial state to the fully closed state. Since the transition is instantaneous, the time lag at the time of non-return can be reduced.

Further, when the valve seat body is formed in a mortar shape whose diameter on the opening side is enlarged, the ball valve body can be stably supported by the inner peripheral surface of the valve seat body. In addition, when the ball valve body is pressed against the valve seat body by being pushed by the flow in the opposite direction, the diameter expansion of the valve seat body and the movement of the ball valve body are performed smoothly. Since a large deformation is not generated in the seat body, the seat body can have high durability.

Further, if a plurality of guide pieces are extended from the end of the valve seat, the ball pieces can be largely swung in the direction perpendicular to the axis of the valve seat by the forward flow. Therefore, the ball valve element can be quickly returned to the initial position, and the time lag of the closing operation can be reduced.

[Brief description of the drawings]

FIG. 1 shows a first example of a ball check valve constructed according to the present invention.
FIG. 2 is a cross-sectional view showing the embodiment.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view showing a closed state of the ball check valve shown in FIG. 1 including a part A and a part B, and a part B shows an open state of a similar ball check valve; It is sectional drawing.

FIG. 4 shows a second example of a ball check valve constructed according to the present invention.
FIG. 2 is a cross-sectional view showing the embodiment.

FIG. 5 is a sectional view taken along line VV in FIG. 4;

6 is a sectional view showing a closed state of the ball check valve shown in FIG. 4, and FIG. 6A is a sectional view showing a closed state of the same ball check valve. It is sectional drawing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Case body 2 Valve room 3 Ball valve body 4 Valve seat body 5 Valve seat plate 6 Support plate 7.8 Joint part 9 Partition part 10/11 Inflow hole 12 Outflow hole 13 Notch groove 21 Valve seat body 22 Guide piece 23 Valve Seat plate

Claims (4)

[Claims] 1. A ball check valve in which a fluid inflow hole opened in a valve chamber inside a case body is closed by a ball valve body, thereby suppressing a backflow of fluid from an outflow hole side. An expandable and deformable cylindrical valve seat body formed of a relatively flexible material having an inner peripheral surface smaller than the ball valve body is protruded from an opening peripheral portion of the inflow hole, and is provided in a reverse flow direction. The ball valve body urged by the fluid pressure fits inside the valve seat body and expands the diameter of the valve seat body while pressing against the inner peripheral surface of the valve seat body to close the flow path. A ball check valve, characterized in that the ball is checked. 2. The inflow hole is provided at one end of the case body, and the outflow hole is provided at the other end side of the case body. In an initial state, the ball valve body is provided with the valve seat body and the outflow hole. 2. The ball check valve according to claim 1, wherein the ball check valve is sandwiched between the hole and an opening edge of the hole. 3. The ball check valve according to claim 1, wherein the valve seat body is formed in a mortar shape whose opening side is enlarged in diameter. 4. A plurality of guide pieces extending in the axial direction with a gap of a predetermined size in the circumferential direction provided so as to surround the ball valve body from an end of the valve seat body. The ball check valve according to any one of claims 1 to 3, wherein: