JP5705679B2 - Needle valve - Google Patents

Description

  The present invention relates to a needle valve that adjusts a minute flow rate.

  Conventionally, this type of needle valve has a valve shaft having a tip formed in a needle shape, and a passage that is opened and closed by inserting and removing the tip of the valve shaft. In this needle valve, the flow rate (trace flow rate) of the fluid flowing from the gap between the tip of the valve shaft and the passage is adjusted by tightening or loosening the valve shaft.

Japanese Patent Laid-Open No. 11-82787

Metering valve (for minute flow control) S / M / L / 31 series, Swagelok product catalog.

  However, in the needle valve described above, when the valve shaft is tightened, the tip end portion of the valve shaft and the inner wall surface of the passage come into contact with each other to cause galling (for example, the prior art of Patent Document 1 and 2 of Non-Patent Document 1). Page technical information). When such galling (hereinafter referred to as valve galling) occurs, the tip of the valve shaft and the inner wall surface of the passage slide sideways, so when the tip of the valve shaft is pulled away from the inner wall surface of the passage. , Requires great power.

  As a measure for preventing valve galling, there is a method in which the tip of the valve shaft and the inner wall surface of the passage are not brought into close contact with each other even when the valve shaft is in the fully closed position. However, in this case, since internal leakage (leakage) occurs in the fully closed state, that is, since the valve is not closed, it is necessary to provide another fully closed valve.

  In addition, if the tip of the valve shaft and the inner wall surface of the passage are brought into close contact with each other in the fully closed position, no internal leakage will occur, but the valve shaft tip and the inner wall surface of the passage can be maintained by maintaining the fully closed state for a long time. May stick (hereinafter referred to as valve sticking), which requires regular maintenance and valve opening / closing. There is also a problem of the above-mentioned valve galling.

  In Patent Document 1, as a measure for preventing valve binding, a fitting plate is fixed to the outer surface of the inner wall of the vacuum apparatus in which a leak hole is formed, and a press plate as a contact seal member is attached to the fitting plate. A configuration in which is pressed with a presser bar is shown. However, in this configuration, there is a portion through which the fluid flows only in a gap having a surface roughness order (about 0.1 to 10 μm). For this reason, the opening when the valve is opened is small, and the application is limited.

The present invention has been made to solve such a problem. The object of the present invention is to close the valve and eliminate the galling of the valve without providing any other valve for full closure. Another object of the present invention is to provide a needle valve capable of separating the valve shaft with a small force.
Further, it is possible to provide a needle valve that can eliminate the need for periodic maintenance and opening / closing of the valve against the sticking of the valve that may be caused by continuing the fully closed state for a long time, and is not limited in application. There is.

  In order to achieve such an object, the present invention provides a needle valve including a valve shaft having a tip formed in a needle shape and a passage opened and closed by insertion and removal of the tip of the valve shaft. A ring-shaped member whose inner peripheral surface faces the entire circumference of the tip of the valve shaft, and an electric circuit that changes the inner diameter of the ring-shaped member by a piezo effect.

  In the present invention, all of the ring-shaped members may be piezoelectric elements, or part of the ring-shaped members may be piezoelectric elements. Moreover, you may make it provide at least 1 or more piezoelectric element in the outer periphery of a ring-shaped member. In this case, the piezoelectric element expands and contracts due to the piezoelectric effect, and the inner diameter of the ring-shaped member changes.

  For example, in the present invention, when the inner diameter of the ring-shaped member is reduced by the piezoelectric effect when the passage by the valve shaft is closed, the inner peripheral surface of the ring-shaped member is brought into close contact with the entire circumference of the tip portion of the valve shaft. Thus, the valve can be closed.

  Further, in the present invention, when the inner diameter of the ring-shaped member is enlarged by the piezoelectric effect when the passage by the valve shaft is opened, the inner peripheral surface of the ring-shaped member is separated from the entire circumference of the tip portion of the valve shaft. It becomes possible to eliminate the galling of the valve. In addition, when the valve is stuck, it is possible to eliminate the sticking by applying a peeling force.

  Further, in the present invention, when the valve is severely stuck, if the ring-shaped member is vibrated by the piezo effect, it is possible to give a larger peeling force and eliminate the severe sticking.

  According to the present invention, the ring-shaped member whose inner peripheral surface faces the entire circumference of the tip portion of the valve shaft in the passage, and the electric circuit that changes the inner diameter of the ring-shaped member by the piezo effect are provided. By reducing or expanding the inner diameter of the ring-shaped member, the valve shaft can be closed without any other valve for full closure, and the valve shaft can be removed with a small force without any valve galling. Can be separated.

  Also, by enlarging the inner diameter of the ring-shaped member, if the valve is stuck, the sticking is eliminated, or if the valve is severely stuck, the ring-shaped member is vibrated. As a result, it is possible to give a greater peeling force to eliminate the severe sticking. As a result, it is possible to eliminate the need for periodic maintenance and opening / closing of the valve against the sticking of the valve that may be caused by continuing the fully closed state for a long time.

  Further, in the present invention, the basic configuration of opening and closing the passage by inserting and removing the tip end portion of the valve shaft is maintained as it is, so that the opening when the valve is opened can be made large, and the application is not limited. .

It is a figure which shows the principal part of 1st Embodiment (Embodiment 1) of the needle valve which concerns on this invention. It is a top view of the ring integrated in the channel | path of the needle valve of this Embodiment 1. It is a figure for demonstrating the operation | movement at the time of closing of the needle valve of this Embodiment 1. FIG. It is a figure for demonstrating the operation | movement at the time of opening of the needle valve of this Embodiment 1. FIG. It is a figure which shows the principal part of 2nd Embodiment (Embodiment 2) of the needle valve which concerns on this invention. It is a figure for demonstrating the operation | movement at the time of closing of the needle valve of this Embodiment 2. FIG. It is a figure for demonstrating the operation | movement at the time of opening of the needle valve of this Embodiment 2. FIG. It is a figure which shows the example which provided the piezoelectric element in a part of ring. It is a figure explaining reduction and expansion of an internal diameter in the example which provided the piezoelectric element in a part of ring. It is a figure which shows the example which provided the piezoelectric element in the outer periphery of the ring. It is a figure explaining reduction and expansion of an internal diameter in the example which provided the piezoelectric element in the outer periphery of the ring. FIG. 3 is an external view showing the entire needle valve cited as a specific example of the first embodiment. It is a longitudinal cross-sectional view which shows the state at the time of opening of the needle valve shown in FIG. FIG. 13 is a longitudinal sectional view showing a state when the needle valve shown in FIG. 12 is closed. It is sectional drawing which shows the state of the principal part at the time of opening of the needle valve shown in FIG. It is sectional drawing which shows the state of the principal part at the time of closing of the needle valve shown in FIG. It is a figure which shows the example which changed the internal diameter of the ring using the motor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[Embodiment 1]
FIG. 1 is a view showing a main part of a first embodiment (Embodiment 1) of a needle valve according to the present invention. In the figure, 1 is a valve shaft (stem) having a tip 1a formed in a needle shape, 2 is a passage opened and closed by insertion and removal of the tip 1a of the valve shaft 1, and the passage 2 is connected to a member 3 called a port. Is formed. The detailed structure of this needle valve will be described later.

  The inner wall surface 2a of the passage 2 is a tapered surface whose inner diameter decreases from the upper side to the lower side in the drawing in accordance with the shape of the tip portion 1a of the valve shaft 1. The inner diameter of the passage 2 is made slightly larger than the outer diameter of the tip portion 1a of the valve shaft 1, and even when the valve shaft 1 is in the fully closed position, the tip portion 1a of the valve shaft 1 and the inner wall surface 2a of the passage 2 are completely formed. And are not supposed to be in close contact with each other.

  A ring-shaped piezo element (hereinafter referred to as a ring) 4 (4A) is incorporated in the opening 2b at the top of the passage 2. The ring 4A corresponds to a ring-shaped member in the present invention. In this example, all of the rings 4A are piezo elements.

  FIG. 2 shows a plan view of the ring 4A. The inner diameter of the ring 4 </ b> A is the same as the inner diameter of the passage 2. That is, in a state where the ring 4A is incorporated in the opening 2b of the passage 2, the inner peripheral surface 4a of the ring 4A and the inner wall surface 2a of the passage 2 are flush with each other.

  An electrical circuit 5 for expanding and contracting the ring 4A is provided for the ring 4A. The electric circuit 5 is a circuit that changes the voltage application state to the ring 4A. When the voltage application state of the electric circuit 5 is switched from the off state to the on state, the ring 4A is contracted and the inner diameter of the ring 4A is reduced. To do. When the voltage application state of the electric circuit 5 is switched from the on state to the off state, the ring 4A expands and the inner diameter of the ring 4A expands (returns to the normal inner diameter). FIG. 1 shows a case where the voltage application state of the electric circuit 5 is turned off.

[Operation when closed]
The operation when the needle valve is closed will be described with reference to FIG. Fig.3 (a) is a figure which shows the state which has opened the needle valve. This state corresponds to the state shown in FIG. From this state, in order to close the passage 2, the valve shaft 1 is tightened and moved in the A direction.

  FIG. 3B shows a state in which the valve shaft 1 is fully tightened (a state in which the valve shaft 1 is in a fully closed position). In this case, the distal end portion 1a of the valve shaft 1 and the inner wall surface 2a of the passage 2 are not completely in close contact with each other, and a slight gap is generated. For this reason, the valve is not galvanized, but internal leakage (leakage) occurs.

  In this state, the electric circuit 5 (FIG. 1) is operated to turn on the voltage application state to the ring 4A, and the ring 4A is contracted (FIG. 3C). Thereby, the inner diameter of the ring 4A is reduced, the inner peripheral surface 4a of the ring 4A is brought into close contact with the entire circumference of the tip portion 1a of the valve shaft 1, and the valve is closed.

[Operation when opened]
Next, the operation when the needle valve is opened will be described with reference to FIG. FIG. 4A is a diagram showing a state in which the needle valve is closed. This state corresponds to the state shown in FIG. In this state, the inner peripheral surface 4a of the ring 4A is in close contact with the entire circumference of the tip end portion 1a of the valve shaft 1, and a state similar to that of the valve is generated.

  When the passage 2 is opened from this state, the electric circuit 5 (FIG. 1) is operated to turn off the voltage application state to the ring 4A, and the ring 4A is extended (FIG. 4B). As a result, the inner diameter of the ring 4A is enlarged, the inner peripheral surface 4a of the ring 4A is separated from the entire circumference of the tip 1a of the valve shaft 1, and the valve is not galling.

  Then, from this state, the valve shaft 1 is loosened and moved in the B direction (FIGS. 4B and 4C). In this case, since there is no galling of the valve, there is no skid frictional resistance, and the valve shaft 1 can be pulled apart with a small force. The state shown in FIG. 4C corresponds to the state shown in FIG.

[Removal of valve sticking]
In the first embodiment, when the passage 2 is opened by the valve shaft 1, the inner diameter of the ring 4A is enlarged (FIG. 4B). Thereby, when the sticking of the valve has occurred, a peeling force can be applied and the sticking can be eliminated. If it is lightly fixed, it can be eliminated by expanding the inner diameter of the ring 4A.

  When the valve is badly adhered, the ring 4A is vibrated by applying an AC voltage from the electric circuit 5 (FIG. 1) to the ring 4A. As a result, it is possible to give a greater peeling force and eliminate the severe sticking.

  As a result, it is possible to eliminate the need for periodic maintenance and opening / closing of the valve against the sticking of the valve that may be caused by continuing the fully closed state for a long time. The vibration of the ring 4A is performed when it is not opened or difficult to open at the time of opening, but may be periodically performed during the fully closed state.

  In the present embodiment, the basic configuration of opening and closing the passage 2 by inserting and removing the tip portion 1a of the valve shaft 1 is maintained as it is, so that the opening when the valve is opened can be made large. The application is not limited like the configuration shown in FIG.

[Embodiment 2]
FIG. 5 is a view showing a main part of a second embodiment (Embodiment 2) of the needle valve according to the present invention. In the second embodiment, the inner peripheral surface 4a of the ring 4B protrudes inward from the inner wall surface 2a of the passage 2 in a state in which the inner diameter of the ring 4 (4B) is reduced and incorporated in the opening 2b of the passage 2. I am doing so.

  In the second embodiment, when the voltage application state of the electric circuit 5 is switched from the off state to the on state, the ring 4B expands, the inner diameter of the ring 4B expands, and the voltage of the electric circuit 5 is applied. When the state is switched from the on state to the off state, the ring 4B is contracted to reduce the inner diameter of the ring 4B (return to the normal inner diameter). FIG. 5 shows a case where the voltage application state of the electric circuit 5 is turned off.

[Operation when closed]
The operation when the needle valve is closed will be described with reference to FIG. Fig.6 (a) is a figure which shows the state which has opened the needle valve. This state corresponds to the state shown in FIG. From this state, in order to close the passage 2, the valve shaft 1 is tightened and moved in the A direction.

  FIG. 6B shows a state in which the valve shaft 1 is fully tightened (a state in which the valve shaft 1 is in a fully closed position). In this case, since the inner peripheral surface 4a of the ring 4B is located on the inner side of the inner wall surface 2a of the passage 2, the inner peripheral surface 4a of the ring 4B is in close contact with the entire periphery of the tip 1a of the valve shaft 1, and the valve The deadline is made.

[Operation when opened]
Next, the operation when the needle valve is opened will be described with reference to FIG. Fig.7 (a) is a figure which shows the state which closed the needle valve. This state corresponds to the state shown in FIG. In this state, the inner peripheral surface 4a of the ring 4B is in close contact with the entire periphery of the tip 1a of the valve shaft 1, and a state similar to that of the valve is generated.

  When the passage 2 is opened from this state, the electric circuit 5 (FIG. 5) is operated to turn on the application state of the voltage to the ring 4B and to extend the ring 4B (FIG. 7B). As a result, the inner diameter of the ring 4B is enlarged, the inner peripheral surface 4a of the ring 4B is separated from the entire circumference of the tip 1a of the valve shaft 1, and the valve is not galling.

  Then, from this state, the valve shaft 1 is loosened and moved in the direction B (FIG. 7B). In this case, since there is no galling of the valve, there is no skid frictional resistance, and the valve shaft 1 can be pulled apart with a small force.

  Then, by operating the electric circuit 5 (FIG. 5), the voltage application state to the ring 4B is turned off, and the ring 4B is contracted (FIG. 7C). As a result, the inner diameter of the ring 4B is reduced and returned to the normal inner diameter. The state shown in FIG. 7C corresponds to the state shown in FIG.

[Removal of valve sticking]
In the second embodiment, when the passage 2 is opened by the valve shaft 1, the inner diameter of the ring 4B is enlarged (FIG. 7B). Thereby, when the sticking of the valve has occurred, a peeling force can be applied and the sticking can be eliminated. If it is lightly fixed, it can be eliminated by expanding the inner diameter of the ring 4B.

  When the valve is badly adhered, the ring 4B is vibrated by applying an AC voltage from the electric circuit 5 (FIG. 5) to the ring 4B. As a result, it is possible to give a greater peeling force and eliminate the severe sticking.

  As a result, it is possible to eliminate the need for periodic maintenance and opening / closing of the valve against the sticking of the valve that may be caused by continuing the fully closed state for a long time. It should be noted that the vibration of the ring 4B is performed when it is not opened or difficult to open at the time of opening, but may be periodically performed during the fully closed state.

  In the present embodiment, the basic configuration of opening and closing the passage 2 by inserting and removing the tip portion 1a of the valve shaft 1 is maintained as it is, so that the opening when the valve is opened can be made large. The application is not limited like the configuration shown in FIG.

  In the first and second embodiments, the ring 4 (4A, 4B) is a ring-shaped piezo element. That is, all of the rings 4 (4A, 4B) are piezo elements. The part may be a piezo element. For example, as shown in FIG. 8, a piezo element 6 a may be provided in a part of the ring 6, and the ring 6 provided with the piezo element 6 a may be used instead of the ring 4. In the ring 6 provided with the piezo element 6a, when the piezo element 6a is reduced in the circumferential direction of the ring 6 (see FIG. 9A), the inner diameter of the ring 6 is reduced. Further, when the piezo element 6a is extended in the circumferential direction of the ring 6 (see FIG. 9B), the inner diameter of the ring 6 is expanded. The ring 6 may be provided with a plurality of piezo elements 6a. In this example, the ring 6 provided with the piezo element 6a corresponds to a ring-shaped member in the present invention.

  Further, as shown in FIG. 10, for example, four piezo elements 8 may be provided on the outer periphery of the ring 7, and the ring 7 provided with the piezo elements 8 on the outer periphery may be used instead of the ring 4. In the ring 7 in which the piezo element 8 is provided on the outer periphery, when the piezo element 8 is contracted in the inner diameter direction of the ring 7 (see FIG. 11A), the inner diameter of the ring 7 is increased. When the piezo element 8 is extended in the inner diameter direction of the ring 7 (see FIG. 11B), the inner diameter of the ring 7 is reduced. In this example, four piezo elements 8 are provided on the outer periphery of the ring 7. However, the number may be any number as long as it is one or more. In this example, the ring 7 corresponds to a ring-shaped member in the present invention.

  In the first and second embodiments, the voltage application state from the electric circuit 5 to the ring 4 (4A, 4B) is the on state and the off state. However, voltages having different polarities may be applied. Good.

[Specific Example of Embodiment 1]
12 to 16 show specific examples of the needle valve of the first embodiment. 12 is an external view showing the entire needle valve, FIG. 13 is a longitudinal sectional view showing a state when the needle valve is opened, FIG. 14 is a longitudinal sectional view showing a state when the needle valve is closed, and FIG. FIG. 16 is a cross-sectional view showing the state of the main part when the needle valve is open, and FIG. 16 is a cross-sectional view showing the state of the main part when the needle valve is closed.

  12 to 15, 10 is a valve stem (stem), 11 is a port, 12 is a valve box, 13 is an input block, 14 is a guide plate, 15 is a ball slide, 16 is a coupling, 17 is a pillar, 18 is Motor plate, 19 is a hollow motor, 20 is a ball screw, 21 is a ball screw, 22 is a fluid introduction pipe, 23 is a fluid outlet pipe, 24 and 25 are joints, 26-1 to 26-3 are O-rings, 27 is It is a seal.

  In this needle valve, the port 11 is a block-like component sandwiched between the valve box 12 and the input block 13, and is a passage that communicates the internal space 12 a of the valve box 12 and the internal space 13 a of the input block 13. 28. The passage 28 corresponds to the passage 2 in the configuration shown in FIG. A ring-shaped piezo element is incorporated as a ring 29 in the upper opening of the passage 28. The ring 29 corresponds to the ring 4A in the configuration shown in FIG. For the ring 29, an electric circuit 30 for expanding and contracting the ring 29 is provided. This electric circuit 30 corresponds to the electric circuit 5 in the configuration shown in FIG.

[Operation when closed]
At the time of closing, the valve shaft 10 is tightened to close the passage 28 from the state shown in FIG. Then, after tightening the valve shaft 10 to the end, the electric circuit 30 is operated to turn on the voltage application state to the ring 29, and the ring 29 is contracted (see FIG. 16). As a result, the inner diameter of the ring 29 is reduced, the inner peripheral surface 27a of the ring 29 is brought into close contact with the entire circumference of the tip portion 10a of the valve shaft 10, and the valve is closed.

[Operation when opened]
When opened, the electrical circuit 30 is operated to open the passage 28 from the state shown in FIG. 14 (closed state), the voltage application state to the ring 29 is turned off, and the ring 29 is extended. Let As a result, the inner diameter of the ring 29 is enlarged, the inner peripheral surface 29a of the ring 29 is separated from the entire circumference of the tip portion 10a of the valve shaft 10, and the valve is not galling. Then, the valve shaft 10 is loosened from this state (see FIG. 15).

[Reference example]
In the above-described embodiment, the piezo element is used to change the inner diameter of the ring, but it can be realized by other methods.

  For example, the ring may be made of a shape memory alloy and thermally deformed. However, this method may be affected by the heat of the fluid. In addition, since the response speed is slow, it takes time to close the valve, which is not suitable for frequent opening and closing.

  Moreover, you may make it change the internal diameter of a ring using a motor or a solenoid. FIG. 17 shows an example using a motor. In the figure, reference numeral 31 denotes a ring, which drives a deformation mechanism 33 by a motor 32 and applies a force in the circumferential direction to the ring 31 via the deformation mechanism 33 to change the inner diameter of the ring 31. However, in such a method, an increase in size is unavoidable, and energy consumption increases.

[Extension of the embodiment]
The present invention has been described above with reference to the embodiment, but the present invention is not limited to the above embodiment. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. Each embodiment can be implemented in any combination within a consistent range.

  DESCRIPTION OF SYMBOLS 1 ... Valve shaft (stem), 2 ... Passage, 2a ... Inner wall surface, 2b ... Opening part, 3 ... Port, 4 (4A, 4B) ... Ring, 4a ... Inner peripheral surface, 5 ... Electric circuit, 6 ... Ring, 6a ... Piezo element, 7 ... Ring, 8 ... Piezo element, 10 ... Valve shaft (stem), 10a ... Tip, 11 ... Port, 12 ... Valve box, 12a ... Internal space, 13 ... Input block, 13a ... Internal space 14 ... Guide plate, 15 ... Ball slide, 16 ... Coupling, 17 ... Column, 18 ... Motor plate, 19 ... Hollow motor, 20 ... Ball screw, 21 ... Ball screw, 22 ... Fluid introduction tube, 23 ... Outlet pipe, 24, 25 ... joint, 26-1 to 26-3 ... O-ring, 27 ... seal, 28 ... passage, 29 ... ring, 29a ... inner peripheral surface, 30 ... electric circuit.

Claims (6)

In a needle valve provided with a valve shaft having a tip formed in a needle shape, and a passage opened and closed by insertion and removal of the tip of the valve shaft,
A ring-shaped member whose inner peripheral surface faces the entire periphery of the tip of the valve shaft in the passage;
An electric circuit that changes an inner diameter of the ring-shaped member by a piezo effect. The needle valve according to claim 1,
The ring-shaped member is
A needle valve characterized in that at least a part thereof is a piezo element. The needle valve according to claim 1,
At least one or more piezoelectric elements are provided on the outer periphery of the ring-shaped member. In the needle valve according to any one of claims 1 to 3,
A needle valve characterized in that an inner diameter of the ring-shaped member is reduced by the piezo effect when the passage is closed by the valve shaft. In the needle valve according to any one of claims 1 to 3,
The needle valve, wherein an inner diameter of the ring-shaped member is enlarged by the piezo effect when the passage is opened by the valve shaft. In the needle valve according to any one of claims 1 to 3,
A needle valve characterized in that the ring-shaped member is vibrated by the piezo effect.

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