JPH07310837A - Swing check valve - Google Patents

Abstract

PURPOSE:To perform easy diagnosis of collision contact between an internal protrusion and a swing arm and wear thereof from the outside by a method wherein an internal protrusion entering the slot of the boss part of a swing arm is formed on the inner surface of a valve body and an external protrusion to which a sensor is set is formed on the outer surface of the valve box. CONSTITUTION:A valve body 23 is pushed up counterclockwise by fluid B, which flows through between a valve seat 21b and the valve body 23. Meanwhile, reflux fluid presses the back of the valve body 23 against a valve seat 21b and closes a flow passage to prevent the occurrence of reflux. In which case, when a gap or a backlash between boss parts 21c and 21d, the boss part 25a of a swing arm 25 of a swing arm 25, and a washer 29 exceeds a friction allowable volume, an internal protrusion 31 is brought into contact with the boss part 25a of the swing arm 25. In this case, a sensor is set to an external protrusion 31 and an impact is exerted on an arm rod 27. When the swing arm 25 is moved and collided with the internal protrusion 31, contact therebetween is detected by a sensor based on a sound and vibration.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art There are various types and structures of check valves, but a swing check valve is used for a pipe having a relatively large flow rate. For example, a swing check valve is provided on the outlet side of a water supply pump such as a boiler to prevent the reverse flow of the water supply. A typical structure thereof will be described with reference to FIGS. 4 and 5. The valve box, that is, the inlet end 1a and the outlet end 1b of the body 1.
Has a tubular shape, and these are joined to the flow path pipe by welding or the like. The upper opening of the body 1 is covered with a cover 3 that closes the upper opening, and is fixed with bolts and nuts. An appropriate gasket is sandwiched between the body 1 and the cover 3 and an appropriate seal gasket is interposed to prevent the internal fluid from leaking. A swing arm 7 is pivotally mounted in the body 1 via an arm rod 5, and a disc-shaped valve body 9 is attached to the lower end of the swing arm 7. That is, the valve body 9
Is a valve that is swingable about the rod 5 and has a seal or valve seat 11 fixed around the inlet passage 1c in the inlet end 1a of the body 1 that rotates clockwise due to its own weight or the like. It is closed by the body 9.

In the above structure, for example, the water supply discharged from the water supply pump flows into the inlet passage 1c as indicated by an arrow F, and the fluid pressure pushes the valve body 9 away (rotates counterclockwise). Then, it flows out from the outlet end 1b.
When the fluid pressure on the inlet side becomes lower than the pressure on the outlet side and the feed water tries to flow backward, the fluid pressure acts on the back surface of the valve body 9, and the valve body 9 is pressed against the valve seat 11. The flow path is closed. That is, backflow is prevented. This is why it is called a check valve.

[0004]

As described above,
In the swing check valve, the pushing force of the forward-flowing fluid and the closing moment due to its own weight balance, the valve body 9 separates from the valve seat 11, and the fluid flows. The fluid flow often pulsates, so that the disc-shaped valve body and the swing arm vibrate all the time. This tendency is particularly noticeable when the flow of the water supply pump is restricted.

When the vibration of the swing arm or the like as described above occurs, the both end surfaces of the base end boss portion, the boss end surface of the inner surface of the body facing the base end boss portion, and the washer and the like interposed therebetween are mutually Rub and wear. When this wear increases, the swing arm is displaced in the longitudinal direction of the arm rod, and the disc-shaped valve element that is normally manufactured with a larger dimension than the outer diameter of the valve seat also comes off the valve seat. The backflow prevention function cannot be achieved. Moreover, such a loss of the backflow prevention function due to the displacement between the valve seat and the valve body is discovered only after it occurs, and the prevention must be disassembled frequently and the inside must be inspected. From the standpoint of maintaining operational efficiency of the plant, such internal inspection was virtually impossible.

The present invention has been made in view of the above circumstances, and it is possible to easily detect the occurrence of wear such as displacement of a swing arm or the like in the lateral direction (direction crossing the flow) from the outside. It is an object to provide a swing check valve having a functional structure.

[0007]

[Means for Solving the Problems] Under such a purpose,
According to the present invention, a valve box in which openings at both ends are joined to the flow path pipe, and a valve seat surrounding the inlet flow path defined in the valve box,
A swing check valve having a swing arm pivotally mounted in the valve box, and a valve body attached to a tip of the swing arm and selectively separated from the valve seat to close the inlet passage, A slot is formed in the boss portion of the base end of the swing arm, and an inner protrusion is formed on the inner surface of the valve box or the valve cover so that the tip end portion is located in the slot and restricts the lateral displacement of the swing arm. It is characterized in that a diagnostic projection is formed on the outer surface of the valve box or the valve cover corresponding to the internal projection.

[0008]

With the above construction, the distance between the lateral end surface of the slot of the swing arm and the end surface of the internal projection, that is, the clearance, is made to be larger than a predetermined allowable value. The arm and internal protrusion do not contact. When the swing arm and related parts wear due to vibration or the like, the lateral displacement of the swing arm gradually increases until the slot end surface of the swing arm comes into contact with the internal protrusion.

Therefore, when the operation of the plant is in an advanced stage, when the operation of the plant is stopped, an acoustic or vibration sensor is set on the external protrusion, and the impact is transmitted to an appropriate place, for example, both ends of the arm rod supporting the swing arm. When,
The swing arm collides with the internal protrusion and generates sound or vibration, which is detected by the sensor.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings. The structure of the entire check valve is the same as the conventional one described above (FIGS. 4 and 5), but the characteristic part of the embodiment of the present invention is shown in the partial enlarged sectional views of FIGS. 1 and 2. ing.

In FIGS. 1 and 2, a valve box or body 21 having an upper opening (used for inserting and assembling internal parts) closed by a valve cover (not shown) defines an inlet passage 21a therein. An annular valve seat, that is, a valve box seat (valve seat) 21b is formed on the inner end surface thereof.
The valve body, that is, the disk 23, which contacts the valve box seat 21b and closes the inlet channel 21a, is fixed by inserting the shaft portion at the center of the rear surface into the lower end of the swing arm 25.

As is particularly apparent from FIG. 2, the base end (upper end) of the swing arm 25 is a boss 25a extending in the lateral direction, which is supported by the arm rod 27 inserted into the body 21. . A boss portion 21c formed on the inner surface of a portion of the body 21 through which the arm rod 27 passes,
21d and the boss portion 25a of the swing arm 25,
A washer 29 of appropriate thickness is interposed to reduce friction and smooth rocking. Both ends of the arm rod 27 are fixed with nuts 37.

Further, the boss portion 25a of the swing arm 25
An inner protrusion 31 is provided on the inner surface of the body 21 so as to face the inside thereof, and the tip of the inner protrusion 31 is inserted into the slot 33 of the boss portion 25a. Both end surfaces of the inner protrusion 31 and both inward end surfaces of the slot 33 are machined, and the amount of the gap between the both is maintained within an appropriate tolerance. And the internal protrusion 3
An external projection 35 is integrally formed on the surface immediately outside of 1.

In the above-mentioned structure, the fluid such as water supply flows in the direction of arrow B, pushes up the disk 23 in the counterclockwise direction, flows between the valve box seat 21b and the front surface (contact surface) of the disk 23, It flows to the outlet (not shown) on the right side of the drawing. Further, the backflow of water from the outlet side exerts a fluid pressure on the back surface of the disk 23 to press the disk 23 against the valve box seat 21b to close the flow path and prevent backflow.

As long as the clearance or play between the boss portion 21c or 21d of the body 21, the boss portion 25a of the swing arm 25, and the washer 29 does not exceed the allowable wear amount, the internal projection 31 is the boss portion of the swing arm 25. 25a does not come into contact with each other, but if the amount of wear increases, they will come into contact with each other. Next, a procedure for inspecting the presence or absence of the contact from the outside will be described with reference to FIG. First, the sensor C electrically connected to the measuring instrument D such as an analyzer is set on the external protrusion 35, and a shock is applied in the longitudinal direction of the arm rod 27 by, for example, a hammer. Accordingly, when the swing arm 25 moves and collides with the internal protrusion 31, a sound or a vibration wave enters the sensor C, and a signal corresponding to the sound or vibration wave enters the measuring instrument D to detect contact.

In the above embodiment (FIGS. 1 and 2), the inner protrusion 31 and the outer protrusion 35 are provided on the body 21, but they may be provided on the valve cover 39 as suggested in FIG. Of course. In this case, the sensor C'is set on the external projection on the valve cover 39 to detect a collision due to movement.

[0017]

According to the present invention, an internal protrusion for entering the slot of the boss portion of the swing arm is provided on the inner surface of the valve box so as to abut against the swing arm when the associated portion is worn, and the sensor is provided. By installing an external projection with the set on the outer surface of the valve box, it is possible to detect the impact of the internal projection and the swing arm by giving an impact to the valve box. It is possible to easily diagnose the degree of progression of.

[Brief description of drawings]

FIG. 1 is a partially enlarged vertical cross-sectional view showing a main part of an embodiment of the present invention taken along the line AA of FIG.

FIG. 2 is a partially cutaway partial enlarged plan sectional view showing an essential part of the embodiment.

FIG. 3 is an explanatory diagram for explaining the operation of the embodiment.

FIG. 4 is a vertical sectional view showing a conventional one. It is a whole systematic diagram of the Example of this invention.

FIG. 5 is a front view showing a conventional one.

[Explanation of symbols]

21 body (valve box), 21a inlet passage, 21b
Valve box seat (valve seat), 23 Disc (valve body), 25
Swing arm, 25a boss, 31 internal protrusion, 33 slot, 35 external protrusion, 39
Valve cover.

Claims (1)

[Claims] 1. A valve box having openings at both ends joined to the flow path pipe, and a valve seat surrounding the inlet flow path defined in the valve box,
In a swing-type check valve having a swing arm pivotally mounted in the valve box, and a valve body attached to a tip of the swing arm and close to and separated from the valve seat to selectively close the inlet passage. Forming a slot in the boss portion of the base end of the swing arm, and forming an internal protrusion located in the slot and restricting lateral displacement of the swing arm on the inner surface of the valve box or the valve cover, A swing check valve, characterized in that a diagnostic external projection is formed on the outer surface of the valve box or valve cover corresponding to the internal projection.