JP4245189B2 - Check valve - Google Patents

Description

  The present invention relates to a check valve disposed in various fluid pipes and the like, and in particular, two semicircular valve plates are provided in a valve body defining a cylindrical flow path. A valve body pivotally supported by the hinge pin is arranged, and the valve body is normally urged to be closed by a spring, and the valve body is opened against the spring by the positive flow pressure of the fluid flowing through the pipe line. In a check valve that closes the valve body by the spring force of the spring when the valve is reduced and stopped, the back surfaces of the valve body repeatedly collide with each other due to abnormal flow or unsteady flow. The present invention relates to a check valve that prevents so-called chattering in which loud noise is generated by vibration.

  In the main body that defines a cylindrical flow path, two semi-disc-shaped valve plates are hinged to one hinge pin in a hinge-like manner, and the two valve plates are always attached by a spring wound around the hinge pin. The valve body is energized in a closed state, and the valve body is opened against the spring by the normal flow pressure of the fluid flowing through the pipeline, and when the normal flow pressure is reduced or backflow occurs, the spring body is repelled by the spring force. Dual plate type check valve that is designed to close the valve is already known.

  In such a check valve, if the flow of fluid is unsteady, it fluctuates due to the fluctuating pressure acting on the two valve plates in the open state, The chattering that the stopper pin or the back surface of the valve body repeated contact with each other and that the valve body vibrates causes a loud noise. Chattering induces not only noise but also breakage of valve parts.

  As shown in Japanese Patent Publication No. 54-12648 (Patent Document 1) and Japanese Patent Application Laid-Open No. 60-125475 (Patent Document 2), a general dual plate check valve has a tapered or straight valve body inlet. In addition, since the outlet of the valve body is formed in a straight shape, fluctuations in pressure applied to the valve body are likely to act, and chattering, noise, and the like are likely to occur. Further, the two valve plates that are pivotally supported by the valve body with hinge pins are combined in the same shape upside down. In other words, since the base part into which the hinge pin is inserted has one valve plate on each of the inner diameter side and the outer diameter side on the same valve plate, when pressure is applied to the valve body, Unbalanced force works and extra torque is generated, which is one of the causes of chattering.

  In order to solve this problem, as disclosed in, for example, Japanese Patent Application Laid-Open No. 9-296874 (Patent Document 3), a buffer material is provided on each downstream surface of the two valve plates so that the valve plates are connected to each other. Attempts have been made to prevent the occurrence of collision noise and damage to the valve body by preventing direct collision of the valve. In Japanese Utility Model Laid-Open No. 4-136371 (Patent Document 4) disclosed by the present inventors, a wing for generating lift for urging the valve body in the valve opening direction is arranged on the upstream surface of the valve body. Attempts have been made to stabilize the valve body in the fully open position when the valve is open, and to prevent chattering and damage to the valve parts.

  According to the technique of Patent Document 3, when chattering occurs due to fluctuating flow or turbulent flow, direct collision between valve plates is suppressed, and generation of large noise is suppressed by reducing the collision by the buffer material. I can do it. However, this method does not prevent the occurrence of chattering itself, so as long as an unsteady flow occurs, the aging of the cushioning material due to the swinging and contact of the valve body is inevitable, resulting in noise. There was a risk of problems such as occurrence and damage. Further, in the check valve described in Patent Document 4, since the valve body is urged in the valve opening direction by the lift generated in the wing, the problem that chattering cannot be suppressed when the lift is small. was there.

Conventional check valves that prevent chattering, or check valves that prevent damage to the equipment due to chattering, are less prone to prevent unsteady flow at locations where flow is likely to occur. Especially when a check valve is connected to a pump for delivering fluid, a strong unsteady flow is generated near the pump, the flow rate is high, and there is pulsation of the pump. It is necessary to make a fluid as stable as possible by interposing a reducer and a straight pipe having a predetermined length or more between the check valve and the check valve. There is a problem that the check valve with the inner diameter is required and the cost is increased.
Japanese Patent Publication No.54-12648 JP-A-60-125475 JP 9-296874 A Japanese Utility Model Publication No. 4-136371

  In view of the above problems, the present inventors have studied in detail the cause of chattering and have completed the present invention to cope with various factors. The cause of chattering is due to the flow of the fluid, due to the structure of the check valve, or due to both of these. Specific main factors include the following.

  1. The valve body is fully opened due to the pressure difference between the front surface (the upstream surface when closed) and the back surface (the downstream surface when closed), but an unstable flow in which the pressure difference fluctuates causes chattering.

  2. The flow of fluid into the space between the two valve plates in the open state is due to inflow from gaps formed at various positions of the hinge portion of the valve body hinged to the hinge pin, but the flow of fluid through the space is Since vortex flow and turbulent flow are generated and the fluid pressure applied to the back surface of the valve body is fluctuated, an unstable flow that causes chattering occurs.

  3. The fluid flowing from the opening opened by the valve body is usually turbulent, and when this turbulent flow passes through the valve body, fluid pressure acting on the valve body surface to generate vortices on the front and back surfaces of the valve body. Fluctuates, causing the valve body to swing.

  4). When the main body inlet is tapered, the fluid flowing in from the main body is concentrated in the inner diameter direction and hits the base of the valve body, and the back pressure increases due to an increase in the flow rate to the back of the valve body (between two valve plates). In addition, the ratio of the fluid hitting the vicinity of the shaft support on the surface of the valve body increases, and the fluid easily hits the valve body at a short distance from the center of the shaft support, resulting in an unstable flow that causes chattering.

  In view of the cause of chattering as described above, the present invention prevents chattering and noise and breakage caused by chattering by preventing the vibration of the valve body and relaxing the contact of the vibrating valve body. It is intended to provide a check valve that can be used.

  In addition, the present invention enables a check valve to be directly connected to the delivery port of the fluid delivery pump, omitting the reducer and straight pipe, which have been indispensable in the past, from the primary side of the check valve, and requiring a reducer. Even in such a case, a check valve can be installed immediately after the reducer, and the straight pipe can be omitted. Thus, the piping space can be greatly reduced, and a small, low-cost check valve is sufficient. In addition, when installing a check valve with a large diameter, the reducer attached to the pump is often opened on one side for space and maintenance. However, by making the check valve unnecessary, Even when a reducer is attached to the wake side, it is possible to use a double-open reducer with less disturbance in the flow velocity distribution.

Means that the invention is taken in order to solve the above problems, the valve body having a cylindrical flow channel, one of a valve body made of semicircular plate shaped two valve plates pivotally supported by the hinge pin In a check valve that is arranged and spring-biased the valve body in a normally closed direction, the inlet shape of the valve body is reduced in diameter by drawing an arc in the radial direction, and the valve seat side outlet end is The shape of the tapered surface that expands in the direction, and the shape of the outlet of the valve main body is the maximum diameter at the valve seat in the valve main body, and the diameter is reduced to a taper shape downstream from the hinge part. The upstream surface of the valve plate is flat, and on the back surface of the two valve plates, a rib extending horizontally is provided at the center, and the ribs located on both sides of the central rib are gradually approached toward the central rib. to so place by providing an inclination of 5 to 10 °, the tube center portion turbulence flowing through the two valve plates and rectified by the ribs Led to a smooth flow, on the outer peripheral side of the valve body back surface, inclined like space of the two valve plates is expanded toward the secondary side is provided, a larger flow path of the two valve plates Thus, the pressure on the back surface of the valve body is decreased, and the pressure difference between the front and back surfaces of the valve body is increased.

  The maximum opening between the two valve plates is 60 ° to 80 °.

  The bases of the two valve plates are formed symmetrically in the vertical direction, and the pressure applied to the valve plates is equalized.

  According to the check valve of the present invention, the valve body can be prevented from swinging, and chattering and noise and breakage caused by the chattering can be highly prevented by relaxing the contact of the swinging valve body. There is an effect.

The check valve of the present invention prevents chattering at a higher level than before, so it is possible to omit straight pipes and reducers, greatly reduce piping space, and be small and low cost. A check valve can be enough.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the figure, (1) is a cylindrical valve body having a fluid passage (2) flowing therethrough, and having a wafer type structure that can be attached to a pipe (4) by being sandwiched between pipe flanges (3). Have. An inlet (5) having a valve seat (8) provided on the inner surface is formed on the upstream side of the valve body (1), and the valve seat (8) is formed at the center of the inlet (5). A central rib (6) is arranged to relieve fluid impingement on the valve body. The secondary side of the fluid passage (2) is formed at the outlet (7). A hinge pin (9) extending in the diametrical direction within the valve body (1) is pivotally mounted at a downstream position of the valve seat (8). The valve seat (8) is made of an elastic sealing sheet such as rubber and closes the inflow port in close contact with the valve body (10).

  Conventionally, the shape of the inlet (5) provided in the valve body (1) is, as shown in FIG. 5a, a tapered portion (22) whose inner diameter decreases from the inlet toward the back, and the valve seat portion (21). However, this shape disturbs the fluid impinging on the valve body and condenses the streamline on the back side of the valve body, that is, on the downstream surface (14). As shown in FIGS. 1c and 5c, the inflow port (5) of the present invention forms a circular arc (16) from the inlet in the radial direction to reduce the diameter, and the valve seat side outlet end is formed in a tapered surface (116). The diameter is increased in the radial direction. By adopting this shape, as shown in FIG. 5b, the inflowing fluid does not converge toward the center of the valve at the inflow port, and the streamline is spread, and the downstream surface (14) of the valve body The flow amount can be reduced, and the pressure difference with the upstream surface (15) of the valve body can be increased. For this reason, the valve body (10) always receives a large urging force and rotates in the valve opening direction, and even if a pressure fluctuation occurs, it is possible to suppress the swing of the valve body due to the influence. Become. Referring to FIG. 5c, the arc (16) is formed with an arc of radius (R), and the valve seat side outlet end is expanded radially by a tapered surface (116) of angle (θ4) as shown in the figure. It has a diameter that promotes the aforementioned streamline spread.

  The valve body (10) is two semicircular valve plates (101) (102) rotatably supported by a base (11) on a hinge pin (9), and is attached to the valve seat (8). The fluid passage (2) can be closed by sitting. The valve body (10) is rotated and opened by the fluid pressure flowing from the inlet side to open the fluid passage (2). The valve body (10) is constantly biased in the valve closing direction by applying a resilient force by a spring (13) wound around the hinge pin (9).

  The valve body (10) is composed of two valve plates (101) and (102), and each downstream surface (14) of the valve plates (101) and (102) has a hinge pin (9) at the center of the valve body. The central rib (104) in the vertical direction and the inclined rib (103) inclined up and down in the axial direction by 5 to 10 ° (angle θ1) with respect to the central rib (104). Is provided. As shown in FIG. 2, these ribs smoothly flow the fluid by rectifying the turbulent flow flowing in from the upstream side of the valve body, and direct the fluid toward the center of the pipe far from the pipe wall of the pipe by the inclined rib (103). The fluid can flow more smoothly, the pressure generated on the back surface of the valve body (10), that is, the downstream surface (14) decreases, and the pressure difference with the upstream surface (15) of the valve body increases. . For this reason, the valve body (10) always receives a large urging force and rotates in the valve opening direction, and even if a pressure fluctuation occurs, it is possible to suppress the swing of the valve body due to the influence. Become. In this example, two inclined flow straightening ribs are provided for each valve plate, but four or more may be provided. In FIG. 2, the hinge pin is omitted for convenience of understanding.

  The base (11) of the valve plate (101) is provided on the inner diameter center side of the valve body (1), and the base (11) of the valve plate (102) is provided on the outer diameter side of the valve body (1). The base of the valve plate is arranged so as to be symmetrical with respect to the center of the semicircle. The valve plates (101) and (102) may be arranged in the left and right direction. Each valve plate base is vertically symmetric, so that the pressure by the fluid applied to the valve body is equal in the vertical direction, and the force on the hinge pin is made uniform when the valve body (10) rotates, so that no excessive torque is generated and smooth. Can be created.

  The downstream face (14) of the valve plates (101) and (102) is between the bases (11), as shown in FIG. 1c and FIGS. An inclination (110) is provided so that the two valve plates are parallel when the valve body is fully open, and an inclination (111) is provided in the outer circumferential direction from that part toward each downstream surface (14). The space is shaped to be expanded in the downstream part. By expanding the space between the valve plates in the downstream portion, the pressure on the surface generated in the inclined portion (111) is reduced, and the pressure difference with the upstream surface (15) of the valve body is increased. For this reason, the valve body (10) always receives a large urging force and rotates in the valve opening direction, and even if a pressure fluctuation occurs, it is possible to suppress the swing of the valve body due to the influence. Become.

  The maximum opening (θ2) of the valve body (10) is limited by the opening limiting means (12) so that the opening is smaller than the conventional valve body opening, that is, 60 ° to 80 °. . By reducing the opening of the valve body (10), the fluid pressure applied to the valve body surface, i.e., the upstream face of the valve body (15) increases, and the pressure difference between the back surface of the valve body, i.e., the downstream face of the valve body (14). Increase. For this reason, the valve body (10) always receives a large urging force and rotates in the valve opening direction, and even if a pressure fluctuation occurs, it is possible to suppress the swing of the valve body due to the influence. Become.

  The opening restriction means (12) is a stopper that restricts the opening degree by the contact between the central rib (104) and the opening restriction means (12). The opening limiting means (12) is not limited to this, and is not particularly limited as long as the maximum opening of the valve body (10) can be limited to 60 to 80 °. (103) may be confronted.

  The outlet (7) provided in the valve body (1) has a maximum diameter at the valve seat part (8) provided in the valve body (1), and the diameter is reduced on the taper downstream from the hinge part. Go (θ3). By this, the fluid that has spread when it passes through the valve seat is contracted on the secondary side of the valve, leading to an increase in the fluid pressure of the surface portion of the valve body (10). The fluid pressure applied to the valve body upstream surface (15) increases, and the pressure difference between the valve body back surface, that is, the valve body downstream surface (14) increases. For this reason, the valve body (10) always receives a large urging force and rotates in the valve opening direction, and even if a pressure fluctuation occurs, it is possible to suppress the swing of the valve body due to the influence. Become. In addition, the taper outlet end portion is adjusted so as to match the inner diameter of the secondary side pipe, thereby eliminating the step with the secondary side pipe and preventing the occurrence of unsteady local vortices generated at the step. By stabilizing the pressure distribution on the body surface, it is possible to suppress pressure fluctuations and suppress swinging of the valve body.

  Although the various chattering prevention structures described above can be expected to have a certain effect even when they are single, it is possible to achieve chattering prevention more effectively by using a plurality of structures together.

  According to the check valve configured as described above, chattering can be prevented to a higher degree than in the prior art. Therefore, as shown in FIG. 6b, the check valve is directly connected to the outlet of the pump (18) that sends out the fluid. The check valve (17) can be connected and used. In particular, according to the present invention, the check valve can be directly connected to the delivery port of the fluid delivery pump, and it is possible to omit the reducer (19) and the straight pipe (20) that have been indispensable in the past. The piping space can be greatly reduced, and a small and low-cost check valve can be obtained. In addition, when attaching a check valve with a large diameter, for the sake of space and maintenance, the reducer (19) attached to the pump is conventionally open on one side as shown in FIG. 6a. As shown, even when a reducer is attached upstream of the check valve, it is possible to use a double-open reducer (19) with less disturbance in the flow velocity distribution.

View of the check valve from the downstream end in the fully closed state Cross section of the check valve Cross section of the check valve in the fully open state 1c, AA line cross-sectional view The figure which shows the flow state of a valve body rib part Figure showing one valve plate (101) Cross section of the valve plate Figure showing the other valve plate (102) Sectional drawing which shows the flow state at the time of the full open of the conventional check valve Sectional drawing which shows the flow state at the time of full open of the non-return valve of this invention C part enlarged view of FIG. 5b A diagram showing the piping condition of a conventional check valve The figure which shows the piping state at the time of connecting the check valve of this invention directly to a pump The figure which shows the piping state at the time of connecting a reducer directly to the upstream of the non-return valve of this invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Valve body 2 Fluid passage 3 Piping flange 4 Piping 5 Inlet 6 Center rib 7 Outlet 8 Valve seat 9 Hinge pin
10 Disc
11 Base
12 Opening limit means
13 Spring
14 Downstream surface
15 Upstream surface
16 arcs
17 Check valve
18 Pump
19 Reducer
20 Straight pipe
21 Valve seat
22 Taper
101 Valve plate
102 Valve plate
103 inclined ribs
104 Central rib
110 tilt
111 tilt
116 Tapered surface

Claims (3)

A valve body consisting of two semi-disc-shaped valve plates pivotally supported by one hinge pin is placed in a valve body having a cylindrical flow path, and the valve body is always attached in the valve closing direction by a spring. In the check valve, the inlet shape of the valve body is reduced in diameter by drawing a circular arc in the radial direction, and the valve body side outlet end is formed into a tapered surface shape that is radially expanded, and the valve body The shape of the outlet of the valve body is the maximum diameter at the valve seat in the valve body, the diameter is tapered down on the downstream side of the hinge, the upstream surfaces of the two valve plates are flat, and two On the back surface of the valve plate, a rib extending horizontally is provided in the center, and the ribs located on both sides of the central rib are arranged with an inclination of 5 to 10 ° so as to gradually approach the central rib, the turbulence flowing through the two valve plates is rectified by the ribs is guided to the tube central portion and smooth flow, the outer periphery of the valve body back surface The space of the two valve plates are inclined as to enlarge toward the secondary side is provided, by enlarging the flow path of the two valve plates, reducing the pressure of the valve element rear surface, a valve body surface A check valve characterized in that the pressure difference between the back surfaces is increased. 2. The check valve according to claim 1 , wherein the maximum opening made by the two valve plates is 60 [deg.] To 80 [deg .]. The check valve according to claim 1 or 2, wherein the base portions of the two valve plates are formed vertically symmetrical to make the pressure applied to the valve plates equal .

Images