JPH09296877A - Valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve capable of decreasing the speed at which a valve is closed by a mechanical means without using an electric means such as a stepping motor. SOLUTION: A valve rod 6 penetrates a valve element 5, and the tip is extended to the vicinity of a recessed part 2a provided on the bottom of a valve casing. A skirt part 9 is provided on the way of the valve rod, and a taper part 10 by which the bottom part side of the recessed part is narrowed is formed in the position facing the skirt part, on the inner periphery of the recessed part. One end side of a bellows extending to the bottom side of the recessed part of the valve casing is attached to the skirt part, and the other end side of the bellows is connected to a ring 12 fixed between it and the recessed part with a clearance C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve, and more particularly to a valve capable of preventing a water hammer that tends to occur in a piping system in which the valve is interposed when the valve is closed.

[0002]

2. Description of the Related Art In a valve such as a solenoid valve, a moving speed of a valve body is so high that when the valve is closed, a water hammer occurs in a piping system in which the valve is interposed, sometimes damaging the valve or the piping. Sometimes. For this reason, conventionally, in order to slow down the moving speed of the valve element, for example, a stepping motor is incorporated in the valve, and by this means, the opening / closing speed of the valve is adjusted.

[0003]

However, the conventional valve incorporating the stepping motor has the following problems. That is, it is necessary to secure a space for accommodating the stepping motor, which increases the size of the valve. Since the stepper motor must be controlled, the electrical interface becomes complicated. Since the stepping motor itself is expensive, there is a problem that the cost becomes high.

The present invention has been made in view of the above circumstances, and the valve closing speed can be slowed down by mechanical means without using electrical means such as a stepping motor, thereby causing the above-mentioned problems. The aim is to provide a valve that can be resolved.

[0005]

In order to achieve the above object, according to the invention of claim 1, a valve seat is provided in the middle of a flow passage formed in the valve casing and faces the valve seat. In the valve that is operated so as to open and close by moving the valve body provided in such a manner through the valve rod in the direction of approaching and separating from the valve seat, the valve rod penetrates the valve body and its tip is A skirt portion is provided extending to the vicinity of the recess provided in the bottom portion of the valve casing, and a skirt portion having an outer diameter smaller than the inner diameter of the recess portion is provided in the middle of the valve rod, while the skirt of the inner peripheral portion of the recess portion is provided. It is characterized in that a tapered portion is formed at a position corresponding to the portion such that the bottom side of the concave portion is narrowed. In the invention according to claim 2, one end side of a bellows extending to the bottom side of the recess of the valve casing is attached to the skirt portion, and the other end side of the bellows is fixed by forming a gap with the recess. It is characterized in that it is connected to the ring. The invention according to claim 3 is characterized in that the tip end of the valve rod is guided while being allowed to move in the axial direction of the valve rod by a guide portion provided at the bottom of the valve casing.

According to the present invention, when the valve body is moved in the closing direction, the volume between the valve body and the concave portion of the valve casing defined below the skirt portion provided in the middle of the valve rod is reduced. A part of the fluid existing in the recess of the valve casing moves to the upper side of the skirt through the gap between the inner periphery of the recess and the outer periphery of the skirt. At this time, as the valve body moves in the closing direction, the gap between the inner peripheral portion of the recess and the skirt portion becomes smaller, and the resistance of the fluid passing therethrough increases. As the flow path resistance of the fluid increases in this way, the moving speed of the valve body in the closing direction becomes slower.
As a result, water hammer is prevented from occurring in the piping system in which the valve is interposed.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a solenoid valve according to the present invention. The valve casing 2 of this valve 1 has an inlet side opening 3
a, the outlet side opening 3b, and the flow path 3 connecting them.

A valve seat 4 is provided in the middle of the flow path 3, and a valve body 5 is arranged so as to face the valve seat 4. Valve 5
A valve rod 6 is continuously provided in the valve, and the valve rod 6 is vertically moved by an actuator 8 such as a valve body opening / closing coil incorporated in the upper portion of the valve casing 2 to move the valve rod 6 vertically. The valve body 5 that moves integrally with the rod 6 moves in the direction toward and away from the valve seat 4, and the valve seat 4
Open and close (see FIG. 2).

The valve rod 6 penetrates the valve body 5, and its tip (lower end) extends to the vicinity of a substantially bottomed cylindrical recess 2a provided in the bottom of the valve casing 2. A substantially disk-shaped skirt portion 9 is concentrically provided in the middle of the valve rod 6. The outer diameter of the skirt portion 9 is set to a value smaller than the inner diameter of the concave portion 2a, and the outer peripheral end of the skirt portion 9 is cut to be thin. Further, a taper portion 10 is formed at a position corresponding to the skirt portion 9 on the inner peripheral portion of the recess 2a (a position corresponding to a range in which the skirt portion 9 moves), in which the bottom side of the recess 2a is gradually narrowed. There is.

A bellows 11 is provided on the lower surface of the skirt portion 9.
One end side of which is attached in a liquid-tight manner, and the other end side of the bellows 11 extends to the bottom side of the recess 2a of the valve casing 2,
It is liquid-tightly connected to a ring 12 having a triangular cross section. As a result, a fluid storage portion 11a that stores the fluid is formed inside the bellows 11. Bellows 11
Has an outer diameter smaller than the inner diameter of the recess 2a,
The recesses 2a can be freely expanded and contracted. Further, the ring 12 is fixed to the bottom portion of the valve casing 2 in a state in which an appropriate gap C that serves as a flow path is formed between the ring 12 and the recess 2a of the valve casing 2.

The tip (lower end) of the valve rod 6 is inserted into a cylindrical guide portion 13 provided at the bottom of the valve casing 2 and guided while allowing the valve rod 6 to move in the axial direction. Does not shift to the left or right.

Next, the operation of the valve having the above structure will be described. Now, when the valve 1 shifts from the open state to the closed state, that is, when the actuator 8 is actuated and the valve body 5 is pushed down via the valve rod 6, the skirt provided in the middle portion of the valve rod 6 The part 9 also descends at the same time. Along with this, the volume of the liquid storage portion 11a inside the bellows 11 below the skirt portion 9 is reduced, and the fluid filling the liquid storage portion 11a, as shown by the arrow in FIG.
2 and the concave portion 2a of the valve casing 2 through a gap C to flow into the space 14 between the outer peripheral portion of the bellows 11 and the inner peripheral portion of the concave portion 2a.
It moves above the skirt portion 9 through the gap between the inner peripheral portion and the outer peripheral portion of the skirt portion 9.

At this time, since the taper portion 10 is formed on the inner peripheral portion of the concave portion 2a, as the valve body 5 moves in the closing direction, the inner peripheral portion of the concave portion 2a and the outer peripheral portion of the skirt portion 9 are formed. The gap between and becomes smaller, and the resistance of the fluid passing therethrough gradually increases (see FIG. 3). Since the flow path resistance of the fluid increases in this way, the moving speed of the valve body 5 in the closing direction becomes slow. As a result, it is possible to prevent water hammer from occurring in the piping system in which the valve 1 is interposed.

On the other hand, when the valve 1 shifts from the closed state to the open state, the skirt portion 9 also integrally rises as the valve rod 6 rises, and as a result, the liquid storage portion 1 inside the bellows 11 rises.
The volume of 1a increases, and at the same time, the liquid storage portion 11a tends to have a negative pressure. However, due to the pressure difference, the fluid in the flow path 3 flows into the space 14 through the gap between the inner peripheral portion of the recess 2a and the outer peripheral portion of the skirt portion 9, and from there, further, the ring 12 and the valve casing. The liquid reservoir 11a is reached through a gap C formed between the two recesses 2a. In this way, as the valve 1 shifts to the open state, liquid accumulates in the liquid storage portion 11a whose capacity increases, and the next valve 1 prepares to shift from the open state to the closed state.

Although the bellows 11 is attached to the lower side of the skirt portion 9 in the above-mentioned embodiment, the bellows 11 is not always necessary, and the closing speed of the valve 1 can be slowed down without the bellows 11. Further, in the above-described embodiment, the skirt portion 9 and the concave portion 2a have a circular cross section so as to correspond to each other, but the present invention is not limited to this and may have a rectangular cross section. Further, the guide portion 13 for guiding the tip end of the valve rod 6 is formed in a cylindrical shape to guide the valve rod 6 in the inserted state, but the present invention is not limited to this, and the guide portion 13 may be guided by concave and convex fitting. Good.

[0016]

As described above, the present invention has the following excellent effects. According to the first aspect of the invention, the closing speed of the valve can be reduced by utilizing the orifice effect between the skirt portion provided on the valve rod and the recess of the valve casing. As a result, it is possible to prevent water hammer from occurring in the piping system in which the valve is interposed. Further, the closing speed of the valve can be arbitrarily adjusted by changing the angle of the taper portion formed on the inner peripheral portion of the recess of the valve casing. Moreover, since the resistance to start closing the valve can be reduced, the driving force required for the actuator can be reduced. Furthermore, since the opening / closing speed of the valve element is slowed by a mechanical means instead of an electric means such as a stepping motor, the electrical interface is simplified and the cost can be reduced. In addition, the entire structure can be simplified, and the size of the valve itself can be reduced and the weight can be reduced. According to the invention described in claim 2, since the bellows is provided in the skirt portion, the flow of the liquid can be forcibly created, and thus the closing speed of the valve can be surely reduced. In addition, resistance also occurs when the fluid passes through the gap between the ring and the recess, and since this resistance is constant regardless of the valve opening, the degree of freedom in giving resistance when the valve closes increases. , The opening / closing speed of the valve can be easily controlled. According to the third aspect of the invention, since the tip of the valve rod is guided by the guide portion, it is possible to expect smooth movement of the valve without rattling of the valve rod.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a valve showing an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view illustrating the flow of fluid when the valve is closed.

3 (a) to 3 (c) are enlarged cross-sectional views of essential parts for explaining the flow of fluid when the valve is closed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 valve 2 valve casing 2a recessed part 3 flow path 4 valve seat 5 valve body 6 valve rod 9 skirt part 10 taper part 11 bellows 12 ring 13 guide part C gap

Claims (3)

[Claims] 1. A valve seat (4) is provided in the middle of a flow path (3) formed in a valve casing (2), and a valve element (5) provided so as to face the valve seat is a valve. In a valve which is moved by a actuator (8) via a rod (6) in a direction toward and away from the valve seat to be opened and closed, the valve rod penetrates a valve body, and a tip of the valve rod is inserted into a valve casing. A skirt (9) having an outer diameter smaller than the inner diameter of the recess is provided in the middle of the valve rod so as to extend to the vicinity of the recess (2a) provided at the bottom, while the inner periphery of the recess is provided. 1. A valve characterized in that a taper portion (10) is formed at a position corresponding to the skirt portion so that the bottom side of the recess is narrowed. 2. The valve according to claim 1, wherein one end side of a bellows (11) extending to a bottom side of a recess of the valve casing is attached to the skirt portion,
A valve characterized in that the other end of the bellows is connected to a fixed ring (12) which forms a gap (C) between the bellows. 3. The valve according to claim 1, wherein the tip end of the valve rod is guided by a guide portion (13) provided at the bottom of the valve casing while allowing the valve rod to move in the axial direction. A valve characterized by being.