JPH028186B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a return prevention valve for a pipe through which liquid such as water flows, and more specifically, to a valve that prevents accidental backflow from the downstream side to the upstream side. be.

[Conventional technology]

Many conventional return prevention valves are of the flap type. This is equipped with a hinged flap (movable plate) and a disc that can be opened and closed in one direction. This type of valve has one flap that pivots like a door.
There are one thing and several things (for example, the French book "Hydrographica" published in 1976, Volume 1, 30~
(See page 39). In addition, a valve has already been proposed in which an output plate with a through passage is arranged downstream of an input plate with a through passage, and a movable valve plate is provided between these input and output plates (Japanese Patent No. 129421). Specification, Tokukaisho
(See Publication No. 54-7607).

[Problem to be solved by the invention]

Conventional valves with one flap have a large mass and a large amount of momentum required to open and close, and the movement of the flap is not an axial displacement, so it takes time to close and cannot quickly prevent backflow, resulting in water hammer effect. ).

A conventional valve with multiple flaps has a smaller momentum of each flap and takes less time to close than one with a single flap, but has a more complex structure and is more expensive.

In addition, in conventional valves with an input/output plate and a movable valve plate, in order to reduce head loss, the direction of flow at the inlet (input axis) and the direction of flow at the outlet (output axis) are aligned with the axis of the pipe. , but these two axes are not in a straight line. Therefore, the liquid flow direction is at an angle to the axis, creating a vortex, and the water head loss is large. Furthermore, a movable valve plate is required in addition to the input/output plate.

Therefore, it is an object of the present invention to provide a return prevention valve that has a simple structure, is low in cost, requires a small amount of momentum to open and close the valve, is capable of rapid operation, and has a minimum water head loss when the valve is opened. It is in.

[Means to solve the problem]

The present invention provides a coupling means for arranging a fixed plate and a movable plate facing each other, each having a plurality of penetrating annular fixed passages and movable passages, and for narrowly restricting the displacement of the movable plate between a valve open position and a valve closed position. The movable plate is connected to the fixed plate by means of the movable plate, and fixed and movable fluid guides are integrally provided in portions of the fixed plate and the movable plate other than the respective passages. These fluid guides are composed of a cylindrical surface, a conical surface, and a base, and the base has a step that faces the other step, and in the valve closed position, the step on the movable plate side is connected to the step on the fixed plate side. Let it be pressed.

The cylindrical surface portion and the conical surface portion of the fixed and movable fluid guides are formed to face the cylindrical surface portion and the conical surface portion of the other party, respectively, and the surface of the conical surface portion is approximately in contact with the corresponding inner wall surface of the partner passage in the valve open position. make it match. Further, the input shaft of each fixed passage of the fixed plate and the output axis of each corresponding movable passage of the movable plate are arranged to be substantially in a straight line. In other words, the distance of each of the former input shafts from the pipe center axis is made approximately equal to the distance of each of the latter output shafts from the pipe center axis. Therefore, each fixing passage of the fixing plate is curved, and the position of its downstream end is shifted in the radial direction by an amount corresponding to the thickness of the base of the fixed fluid guide.

[Effect]

Upstream and downstream away from the non-return valve, the liquid is flowing at a normal, uniform axial velocity. If the diameters of the upstream and downstream sides of the pipe are the same, and the output and input axes of the liquid flow of the anti-return valve are not aligned and separated, the liquid will be normally uniform both upstream and downstream near the valve. cannot flow at an axial velocity of That is, a non-straight flow of liquid results in swirling and the liquid flows at a normal, uniform axial velocity away from the valve. This diagonal liquid flow and swirl causes head loss.
Therefore, as in the present invention, when the input and output axes are aligned almost in a straight line when the liquid flow passes through the valve,
Head loss is significantly reduced.

It is well known that in order to prevent backflow in a short time, it is necessary to reduce the displacement (stroke) of the movable plate, but conventional valves with a movable valve plate between the input and output plates are The shorter the communication path between the input and output plates at a given position, the greater the water head loss. However, in the present invention, the above-described configuration suppresses the water head loss to a low level even though the displacement of the movable plate is small. The first reason is that the input and output axes of the liquid flow are arranged on almost the same radius from the center axis of the pipe as mentioned above, and the second reason is that the space between the fixed and movable plates is horizontally spaced. The cutting liquid flow is carefully guided by the guiding fluid, so that the liquid flows in the center of the passage from beginning to end.

〔Example〕

Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention in a valve open state, FIG. 2 is a view showing half of the upstream surface of the fixed plate in FIG. 1, and FIG. 3 is a movable view in FIG. FIG. 3 is a view showing half of the downstream side of the plate.

In these drawings, 11 is the liquid pipe 1
12 indicates the downstream part of the pipe, each of which has connection flanges 13 and 14 at its ends, and these flanges have holes 15 and 12 for connection with bolts (not shown). 16
There is. The arrow indicates the normal flow direction of the liquid flowing through the pipe 1.

The fixing plate 2 is located between the two connecting flanges 13 and 14, and has a hole 28 in its outer ring (rim) 29 sandwiched between the two flanges. Pass the bolt through. The fixing plate 2 also has a plurality of holes passing coaxially around the central axis of the pipe 1, each of these holes forming a fixing passage 20 for the liquid flow. Each fixed passage 2
0 is curved in the axial direction as shown in FIG. 1 for reasons described later, and the positions of the upstream end and the downstream end are shifted in the radial direction. The cross section (cross section) of each fixed passage in a direction perpendicular to the axis of the pipe is annular as shown in FIG.

A movable plate 3 is disposed on the downstream side of the fixed plate 2 and opposite thereto.
to be placed. Like the fixed plate, the movable plate 3 also has a movable passage 30 coaxially penetrating around the central axis of the pipe and having an annular cross section (FIG. 3).

As shown in FIG. 1, each fixed passage 20 becomes gradually narrower along the liquid flow direction, and each movable passage 30 gradually widens.

The parts between adjacent fixed and movable passages 20, 30 form coaxial rings 21, 31, which are separated from each other by spacing pieces 23, 33 radially mounted on the central hubs 22, 32. Link. The other end of the spacer piece 23 is fixed to an outer ring 29 of the fixed plate.

The movable plate 3 is slidably accommodated in a recess formed by the inner wall 17 of the outer ring 29 of the fixed plate and the inner wall of the flange 14. That is, the central hub 3 of the movable plate 3
A threaded rod (bolt) 6 is slidably inserted through 2, and its tip is screwed to the central hub 22 of the fixed plate. Then, insert the spring 61 back between the bolt head 62 and the central hub 32. In this way, the movable plate 3 is slidably connected to the fixed plate 2 by the coupling means 6, 61, and 62, but its slidable range (displacement) is limited by the return spring 61. In the present invention, the coupling means 6, 61, 62 are configured so that the displacement of the fixed plate 3 is small.

The fixed and movable passages 20 and 30 are connected to the input shaft of the fixed passage (in the direction in which liquid flows) in the valve open position.
It is configured such that the extension of the movable passage 30 substantially coincides with the output axis (direction in which liquid flows out) of the corresponding movable passage 30.
The entrance surface of the fixed passage 20 is configured such that the input axis is parallel to the axis of the pipe, and the movable passage 30 is configured such that the input axis is parallel to the axis of the pipe.
The outlet face of is configured such that the output axis is parallel to the axis of the pipe.

The width of the fixed passage 20 in the radial direction decreases from the upstream side to the downstream side, and the width of the movable passage 30 in the radial direction increases from the upstream side to the downstream side. It is narrower and located further away from the central axis of the pipe than the inlet and outlet sections. That is, the fixed passageway 20 deflects the flow outward, but the movable passageway 30
returns about the same amount of flow inward.

At the downstream end of each coaxial ring 21 of the fixed plate 2, a fixed fluid guide 4 in the form of an annular projection projecting toward the movable passage 30 and having a cross section resembling a nose is integrally formed. Each of these fixed fluid guides has a cylindrical surface portion 41 corresponding to the inner wall of the annular projection and a conical surface portion 42 corresponding to the outer wall of the annular projection. Upstream of these cylindrical surface portion and conical surface portion, that is, at the base of the annular projection, a step portion 43 is formed within the same cross section.

Similarly, at the upstream end of each coaxial ring 31 of the movable plate 3, a movable guide fluid 5 in the form of an annular protrusion projecting toward the fixed passage 20 and having a cross section resembling a nose is integrally formed. Each of these movable fluid guides has a cylindrical surface portion 51 corresponding to the outer wall of the annular projection and a conical surface portion 52 corresponding to the inner wall of the annular projection. A step portion 53 having the same cross section is also formed on the downstream side of the cylindrical surface portion and the conical surface portion of the movable fluid guide, that is, at the base of the annular projection.

Therefore, the cylindrical surface portion 41 and the conical surface portion 42 of each fixed fluid guiding fluid 4 are opposed to the cylindrical surface portion 51 and the conical surface portion 52 of each movable fluid guiding fluid 5, respectively, and the upper stage of the stepped portion 43 of each fixed fluid guiding fluid 4 is Each movable guiding fluid 5
The lower part of the step part 53 and the lower part of the step part 43 are the step part 53.
They are opposite the upper row of each.

Each of the fixed and movable guiding fluids 4, 5 is located between each of the opposing fluid guiding fluids, so to speak, in a staggered arrangement.

If the liquid flows in the normal direction in pipe 1,
The movable plate 3 is pushed downstream against the force of the return spring 61 and comes to the illustrated valve open position away from the fixed plate 2. At this time, the surfaces of the respective conical surfaces 42 and 52 of the respective fluid guides 4 and 5 of the respective coaxial rings 21 and 31 are located substantially on extension surfaces of the adjacent inner walls of the movable and fixed passages 30 and 20, respectively. On the other hand, the surfaces of the respective cylindrical surfaces 41 and 51 of the respective fluid guides 4 and 5 face each other. Further, the input shaft of each fixed passage 20 substantially coincides with the output axis of each corresponding movable passage 30. In other words, the input shaft and the output shaft are substantially in a straight line. As mentioned above, the fixed and movable guiding fluid 4,
5 are arranged alternately, the fixed passage 20 is slightly larger, and the movable passage 30 is slightly curved in the axial direction so that both axes are aligned.

Here, the thickness of the fixed plate 2 (former) and the fixed passage 2
The relationship with the radial width of 0 (the latter) will be described. When the former is 1.6 times the latter, the flow guiding efficiency of the fixed passage is greater than when it is 1.2 times. However, when the former is four times the latter, the guiding efficiency is almost the same as when it is three times the latter. That is, when the former is less than twice the latter, the greater the former (thickness), the greater the flow guiding efficiency of the fixed passage. The reason for this is thought to be as follows. When a liquid flows in a passage of a certain width, the longer the passage, the closer the flow direction is to the longitudinal direction of the passage, and even if there is a swirling flow at the entrance of the passage, there is a greater possibility that it will disappear by the time it reaches the outlet. It is. That is, the longer the length of the passage in the longitudinal direction, the more uniform the liquid flow at the outlet of the passage becomes in the longitudinal direction. Therefore, the thickness of the fixing plate 2 is preferably about twice the radial width of the fixing passage 20.

With the above-described configuration, the liquid jet in the fixed channel 20 is guided directly in the direction of the movable channel 30 and flows in the middle of the movable channel, so that the head losses in normal directional flow are significantly reduced.

If the flow is accidentally reversed, the movable plate 3 is quickly pushed back toward the fixed plate 2 due to the small distance between the fixed and movable plates and the restoring force of the return spring 61. Although the return spring 61 may act only at the beginning of the operation when the valve is closed, it serves as an elastic stopper for the movable plate when the valve is closed. Each movable guide fluid 5 enters into the fixed passage 20 opposite thereto, each fixed guide fluid 4 enters into the movable passage 30 opposed thereto, and the stepped portion 53 of each movable guide fluid enters each fixed passage opposite thereto. It comes into close contact with the step portion 43 of the fluid guide. The valve is thus in the closed position and backflow is automatically prevented.

Since the displacements required for the opening and closing movements of the movable plate 3 are small, they are sufficient, so that, according to the invention, the operation of the valve is very rapid and therefore water hammer effects are also avoided. For even faster operation, the movable plate 3 may be made of a less dense material, such as plastic.

Although the preferred embodiments of the present invention have been described above, various modifications and changes can be made as long as they fall within the structure set forth in claim 1.

〔Effect of the invention〕

The effects of the present invention are as follows.

(a) Compared to conventional valves that have an input plate, an output plate, and a movable valve plate (three parts), only two are required, a fixed plate and a movable plate, so the structure is simpler and the price can be lowered.

(b) Since the displacement of the movable plate is a small movement along the axial direction, rapid movement is possible. Therefore, there is no possibility of water hammer effect occurring.

(c) The liquid flow passing through the fixed and movable passages flows through the center of the passage at a substantially uniform axial velocity without creating any vortices, so head losses are significantly reduced.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention in a valve open state, FIG. 2 is a view showing half of the upstream surface of the fixed plate in FIG. 1, and FIG. 3 is a movable view in FIG. FIG. 3 is a view showing half of the downstream side of the plate. Note that the reference numerals in the drawings are shown in addition to the corresponding constituent elements in the claims, and therefore redundant description will be omitted.

Claims (1)

[Scope of Claims] 1. A return prevention valve for a liquid pipe 1 consisting of a fixed plate 2 and a movable plate 3 disposed opposite to and downstream thereof, wherein the fixed plate and the movable plate each have a plurality of penetrating plates. fixed and movable passages 20, 30 with an annular cross section of
The movable plate 3 has a valve open position where the two plates are separated from each other and liquid flows from upstream to downstream through the respective passages, and a valve open position where the two plates are in contact with each other and each passage is connected to the other plate. The coupling means 6, 61, 62 narrowly limit the displacement of the movable plate between the valve open position where the flow of the liquid from the downstream side to the upstream side is blocked by the fluid guides 4, 5. The fixed plate 2 is connected to the fixed and movable passages 20 and 3, and the fluid guide is connected to the fixed plate 2.
The above-mentioned fixed and movable plates 2 and 3 in parts other than 0
a plurality of fixed fluid guiding fluids 4 and a plurality of movable fluid guiding fluids 5, which are provided integrally with the movable passageway and protrude toward the upstream end of the movable passage and the downstream end of the fixed passageway, respectively; The step portions 43 and 53 are formed to face the step portions 53 and 43 of each other, respectively, and each of the fixed and movable fluid guides is formed to face the cylindrical surface portions 51 and 41 and the conical surface portions 52 and 42 of each other, respectively. cylindrical surface part 41,
51 and conical surface portions 42, 52, each of the fixings is configured such that the input axis of each fixed passage 20 of the fixed plate 2 is substantially in line with the output axis of the corresponding movable passage 30 of the movable plate 3. A non-return valve characterized in that the passage 20 is axially curved and its downstream end is radially displaced approximately corresponding to the thickness of the base of each fixed fluid guide 4. 2 In the valve open position, the conical surface portion 42,
2. A valve according to claim 1, wherein each of the faces of 52 lies substantially on an extension of the corresponding inner walls of the mating fixed and movable passages. 3. The valve according to claim 1, wherein the coupling means includes a spring 61 for pushing the movable plate 3 back toward the fixed plate 2. 4. A valve according to claim 1, wherein the movable plate 3 is made of plastic material.