JP2000249233A - Flow regulating type needle valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To widen to the utmost the control range of a minute flow, meanwhile set the flow large at full opening, by changing the flow passage area in the most approached opposed condition between the nearly straight part and multi- stepped slopes and a plurality of throttle parts based on the position of a valve element. SOLUTION: The closed part 17c of a valve element 17 on the most descent position is brought in contact with the bottom part of a valve seat 5 to be in the full closed condition. Under the condition, for example, when a motor 19 such as a pulse motor is rotationally moved by a pulse signal or the like, an output shaft 23 is rotationally moved, and threadedly engaging the thread part 23a of the output shaft 23 with an insert thread 22, a connector 21 is elevated. When the connector 21 is elevated, the valve element 17 is moved upward through a connector shaft 20. Namely, at first a minute flow passage area between the first throttle part of the valve seat 5 and the lower end part position of the vertical part of the valve element is changed to a minute flow passage area part between the first throttle part and the lower end part position of a micro-taper face having long stroke.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow control type needle valve, and more particularly, to a needle valve capable of controlling a wide range of minute flow rate.

[0002]

2. Description of the Related Art Conventionally, globe valves and needle valves have been known as adjusting valves for adjusting the flow rate of a fluid.
In these valves, since the flow rate is adjusted only by the gap between the valve body and the seat, the relationship between the valve opening and the Cv value is shown in FIG.
As shown by the one-dot chain line, it appears as a change in the proportional relationship.

[0003] For this reason, for example, when adjusting the flow rate of the cooling and heating medium, these adjustment valves require a flow rate adjustment from a fully closed state to a predetermined valve opening degree at a very small flow rate. When it was necessary to increase the flow rate, the valve structure was inappropriate.

To solve these problems, for example, Japanese Patent Application Laid-Open No. 9-296868 has been proposed. This publication describes an electric valve in which the flow rate is adjusted in a gap between an annular valve seat and a valve body, and the valve body is moved up and down by an electric motor such as a pulse motor to control the flow rate.

However, according to the above publication, the flow rate can be adjusted very finely. / 4000 = 1/8), which is difficult to control, and is not suitable for applications requiring a very small flow rate range. The present invention has been developed in view of the above-described conventional problems, and has as its object to adjust the flow rate so that the control range of the minute flow rate can be increased as much as possible, while the flow rate can be increased when fully opened. It is to provide a needle valve of the type.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a needle valve in which the front end of a rod-shaped valve body is inserted into a valve seat having a through hole to adjust the flow rate. On the outer periphery, a closing portion seated on the valve seat, a substantially linear portion in the axial direction of the rod, a multi-stage inclined portion provided ahead of the closing portion, an annular seat portion, a plurality of throttle portions provided on the valve seat side, The flow rate adjusting needle valve is configured such that a flow path area in a state where a substantially straight portion, a multi-stage inclined portion, and a plurality of throttle portions are in the closest state is switched depending on the position of a valve element.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a flow regulating type needle valve according to the present invention will be specifically described with reference to the drawings. FIG.
In this embodiment, an inflow port 2 and an outflow port 3 are provided at an angle in a metal body 1, and a valve chamber 4 is provided in a flow path of the outflow ports 2 and 3.
Is provided. An annular valve seat 5 made of metal, resin or other material is mounted on a step 1a formed on the inflow port 2 side of the valve chamber 4, and a through hole 6 of the valve seat 5 A first tapered portion 7 and a second throttled portion 8 are formed at the upper and lower end portions of the valve seat 5 by providing a minute tapered surface 6a extending toward the other end.
A seat portion 5a having a taper surface of about 45 ° is provided on the inner periphery of the upper end of the valve seat 5.

A groove 9a of a metal holding ring 9 is fitted into the upper part of the valve seat 5, and a stem guide 10 described later is provided.
The holding ring 9 securely holds the valve seat 5 on the stepped portion 1a with the pressing force described above, and further forms a notched stepped portion 5b on the lower surface of the valve seat 5 so that the first throttle portion 7 does not hit the body 1. I have.

Further, a cylindrical stem guide 10 made of resin is inserted through the upper opening of the body 1 into the valve chamber 4 of the body 1 via the O-ring 10b, and the lower end of the stem guide 10 is connected to the O-ring 10a. While pressing the holding ring 9, the flange 10 c formed in the middle of the stem guide 10 and the upper part of the body 1 are fixed with bolts 11, and the valve seat 5 and the holding ring 9 are pressed against the body 1 by the stem guide 10. It is fixed. Further, on the inner peripheral surface of the stem guide 10, cylindrical stem bearings 12a, 12b made of resin are provided.
(One stem bearing may be used) O-ring 1
It is charged via 3a and 13b.

Further, an annular heat insulating space 14 is provided on the outer peripheral surface of the stem guide 10 so that a resin spacer 15 is attached to the bolt 1.
6 is fixed to the body 1. On the upper surface of the spacer 15, a mountain-shaped inclined surface 15a inclined from the center is formed, and the condensed water flows outward by the inclined surface 15a. Also, on the upper part of the spacer 15,
A metal bracket 18 having a U-shaped cross section is fixed by screws (not shown), and a motor 19 such as a pulse motor is fixed to the upper surface of the bracket 18 by screws.

In FIG. 2, reference numeral 17 denotes a rod-shaped valve element made of metal.
7a, a vertical portion 17b inserted into the tapered portion 9b of the holding ring 9 in front of the flange 17a, and a tapered seal seated in the seat portion 5a of the valve seat 5 in front of the vertical portion 17b. A closing portion 17c which is a surface is provided.

A substantially straight portion 17d having a long stroke (lift surface) occupying 50% or more of the needle portion of the valve element 17 is provided in front of the closing portion 17c. The substantially straight portion 17d in FIG. 2 includes a vertical portion 17e and a minute taper surface 17f following the vertical portion 17e. The minute taper surface 17f has a minute taper angle of 1 ° 30 ′ with respect to the axial direction of the valve element 17 ( This minute taper angle is appropriately selected). As another example, the substantially straight portion 17d
May be entirely in the shape of a plane perpendicular to the axis of the valve element 17. Further, the substantially straight portion 17d includes all cases in which the whole is formed as a minute tapered surface. The substantially straight portion 17d is arbitrarily selected.

Further, a plurality of inclined portions 17g and 17h are provided in front of the substantially straight portion 17d, and a tip spherical portion 1
7i. At the rear end of the rod-shaped valve body 17, a screw portion 20b of a resin connector 20 shaft is screwed, and this connector shaft 20 is connected to the cylindrical stem bearings 12a, 12a.
The guide is movable up and down inside b.

The upper end of the connector shaft 20 is
The female thread 21a of the resin connector 21 is screwed to the exposed male thread 20a. Accordingly, the rod-shaped valve element 17, the connector shaft 20, and the connector 21 are screwed and integrated to form the stem bearings 12a, 12b.
Guided by In this case, the connector 21
And the connector shaft 20 may be provided integrally.

Further, a charging hole 21 formed in the connector 21 is provided.
b, a metal insert screw 22 is integrally formed and fixed non-rotatably.
The connector 21 is vertically movably provided by screwing a screw portion 23a of the output shaft 23, and a vertical engaging groove 24 is formed on one side of the connector 21. On the other hand, the bracket 18 has a distal end made of PTFE or the like. Bending member 2 fitted with a tube 25a
5 is fixed, and the bending preventing member 25 is engaged with the engaging groove 24 to prevent the connector 21 from rotating. By providing the function of the bending preventing member 25 as a positioner, the position detection of the valve body and the rotation preventing may be used together.

Further, the lower end of the connector 21 and the spacer 15
An elastic member 26 such as a coil spring for preventing hysteresis is interposed at the upper end of the head. Therefore, the connector 21 is urged upward by the elastic member 26 and the insert screw 22
And the lower tooth surface of the screw portion 23a always contact. In this case, the elastic member 26 may be provided between the upper end of the connector 21 and the bracket 18. In the figure, 27,
28 is an O-ring, 29 is a sealing material formed of a material such as PTFE.

Further, the stem bearings 12a, 12b
Is made of a resin such as PTFE, and the spacer 15, the stem guide 10, the connector 21, and the connector shaft 20 are made of a resin such as PPS, so that the heat conductivity is reduced and dew condensation in the case of a low-temperature fluid is reduced. Prevents freezing and reduces the effects of high temperature fluids.

Next, the operation of the above embodiment will be described. The state shown in FIG. 1 shows the closing portion 1 of the valve body 5 at the lowest position.
7c is in contact with the seat 5c of the valve seat 5 and is in a fully closed state. In this state, for example, a motor 19 such as a pulse motor is used.
Is rotated by a pulse signal or the like, the output shaft 23 rotates, and the screw 21 a of the output shaft 23 is screwed into the insert screw 22 to raise the connector 21.

When the connector 21 rises, the connector shaft 2
The valve body 17 moves upward via the zero and the minute flow rate is adjusted stepwise over a wide range in the relationship shown by the solid line in FIG. That is, first, as shown in FIG. 5, the first throttle portion 7 of the valve seat 5 shown in FIG. The flow path changes to a small flow path area B between the narrowed portion 7 and the lower end portion of the small tapered surface 17f having a long stroke.

As shown in FIG. 11, by extending the stroke from the fully closed position to the inflection point B in FIG.
It has become possible to expand the range of minute flow as much as possible.

Further, the second throttle portion 8 of the valve seat 5 shown in FIG.
And the flow path area C with the lower end portion of the substantially straight portion 17d having a long stroke. Next, in FIG.
In FIG. 9, the flow path area E between the second throttle part 8 of the valve seat 5 and the lower end part of the inclined part 17h is changed to the flow area D of the second throttle part 8 and the lower end part of the inclined part 17g. Further, toward the fully opened state in FIG. 10, the flow rate is changed to the narrowed portion 9c of the holding ring 9 and the flow path area F of the inclined portion 17h so that the flow rate can be maximized.

Further, the connector 21, the connector shaft 20, the spacer 15 and the like can be made of resin to be in a heat insulating state, and the engagement state between the insert screw 22 and the output shaft 23 of the motor 19 is an elastic member such as a coil spring. Since the urging force of 26 always keeps on the same side of the thread, there is no possibility that the hysteresis, that is, the position shift occurs when the valve body 17 moves up and down, and the flow rate can be controlled with high accuracy.

Further, an insert screw 22 is
Are integrally formed, the threaded portion 23a of the output shaft 23 and the metal are screwed together to improve durability and withstand long-term use. This needle valve is particularly excellent in applications that require a wide range of high-precision micro flow rates, for example, in the delivery of cold and hot media, pure water, chemical solutions, and the like.

[0023]

As described above, according to the present invention, the control range of the minute flow rate can be widened, which is suitable for a needle valve which requires a wide range of the minute flow rate, and increases the flow rate when fully opened. Can

In addition, it is possible to provide a high-precision flow-adjustable needle valve without causing hysteresis due to the function of the elastic member, and the durability is good.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a fully closed state of a flow-regulating needle valve according to the present invention.

FIG. 2 is a partially enlarged view showing the rod-shaped valve element of FIG.

FIG. 3 is an enlarged sectional view of a valve seat.

FIG. 4 is an enlarged sectional view of a retaining ring.

FIG. 5 is a partially enlarged schematic view showing a state where the operation is performed from the fully closed state in FIG. 1;

FIG. 6 is a partially enlarged schematic view showing a state in which the operation is performed from FIG. 5;

FIG. 7 is a partially enlarged schematic view showing a state where the operation is started from FIG. 6;

FIG. 8 is a partially enlarged schematic view showing a state where the operation is started from FIG. 7;

FIG. 9 is a partially enlarged schematic view showing a state where the operation is performed from FIG. 8;

FIG. 10 is a partially enlarged schematic view showing a state where the operation is started from FIG. 9;

FIG. 11 is a flow rate characteristic diagram of a flow rate adjustment type needle valve.

[Explanation of symbols]

 Reference Signs List 5 Valve seat 5a Seat part 7 First throttle part 8 Second throttle part 17 Valve element 17c Closed part 17d Substantially linear part 17g, 17h Inclined part

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[Procedure amendment]

[Submission date] April 26, 1999 (1999.4.2
6)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction contents]

Further, a throttle portion 9c is provided above the valve seat 5.
Fitting grooves 9a of the metal retaining ring 9 having, described later stem by retaining ring 9 by the pressing force of the guide 10 is securely hold the valve seat 5 on the step portion 1a, cut-out step portions 5b further to the lower surface of the valve seat 5 Is formed so that the first throttle portion 7 does not hit the body 1.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

Further, the second throttle portion 8 of the valve seat 5 shown in FIG.
And the flow path area C with the lower end portion of the substantially straight portion 17d having a long stroke. Next, in FIG.
In FIG. 9, the flow path area E between the second throttle part 8 of the valve seat 5 and the lower end part of the inclined part 17h is changed to the flow area D of the second throttle part 8 and the lower end part of the inclined part 17g. changes to, further, toward the fully opened in FIG. 10, the retaining ring 9, the upper
Instead of the first and second throttle portions 7 and 8 described above, the throttle portion 9c and the flow passage area F of the inclined portion 17h are provided, so that the flow rate can be maximized.

[Procedure amendment 3]

[Document name to be amended] Drawing

[Correction target item name] FIG.

[Correction method] Change

[Correction contents]

FIG. 10

Claims (1)

[Claims] 1. A needle valve for adjusting the flow rate by inserting the front end of a rod-shaped valve body into a valve seat having a through-hole, on the outer periphery near the front end of the valve body, a closing portion seated on the valve seat and a position ahead of the closing portion. A substantially linear portion in the axial direction of the rod and a multi-stage inclined portion are provided, and an annular seat portion and a plurality of throttle portions are provided on the valve seat side. A flow-regulating needle valve in which the flow path area in the facing state is switched according to the position of the valve element.