JP5120774B2 - Low loss flap valve - Google Patents

Description

  The present invention relates to a reduction in loss of a flap valve which is disposed in a discharge pipe such as a water channel, a pipe, and a discharge end of a pump to prevent back flow to the discharge pipe.

  A conventional backflow prevention flap valve has a valve body attached to the discharge end of a water channel or various pipes, and a valve body is suspended swingably on arms fixed to both upper ends of the valve body, and is opened by the water flow of the discharge pipe. However, it is well known that it closes due to its own weight as the water flow decreases. However, in this known flap valve, the opening moment due to the water flow acts on the valve body at the time of opening, and the valve body opens, but also at this time, the closing moment due to the weight of the valve body always acts, Pressure loss is caused to the water flow.

In order to reduce the pressure loss due to the weight of the valve body, one end of the bell crank-shaped swing link is pivotally supported by brackets fixed to both upper ends of the door body, and the bent portion of the swing link is It is pivotally supported by a bracket fixed to the top of the tube box, and a balance weight is provided at the other end of the bell crank-shaped swing link to reduce the closing moment due to the weight of the door body and reduce pressure loss. A flap gate constructed as described above is described in Patent Document 1. Also, the door body is lifted vertically by a small distance with the first hydraulic cylinder using the link mechanism, and then lifted while rotating the lower part of the door body outward with the second hydraulic cylinder to open the outlet. A link gate is disclosed in Patent Document 2.
JP-A-11-181748 JP 2002-088748 A

  As described above, the conventional flap valve has a problem that the opening angle is small and the loss is large due to the effect of the closing moment due to the dead weight of the valve element that always operates during opening. In order to solve this problem, the invention of Patent Document 1 uses a balance weight that balances with the valve body in order to reduce the closing moment due to the weight of the valve body, thereby reducing the pressure loss by reducing the closing moment. It is reduced. For this reason, compared to the conventional flap valve, a balance weight and a member such as an arm for arranging the balance weight are required, and the weight including the valve body becomes heavy, so that the strength of the valve shaft for rotating the valve body is also increased. Necessary. Furthermore, there is a problem that a space for operating the balance weight portion is also required above the flap valve. Further, in the invention of Patent Document 2, in order to make the pressure loss zero without being affected by the closing moment due to the weight of the valve body, a hydraulic cylinder, a link mechanism, a driving machine, a control device, etc. that forcibly open and close the valve body Equipment is required, and space for installing these equipment is required. Furthermore, construction such as hydraulic piping and electrical work is necessary, and there is a problem that the maintenance cost of these devices increases.

In order to achieve the problem to be solved by the above invention, the present invention includes a valve body disposed at a discharge end of a discharge pipe, and a valve body that opens and closes an opening of the valve body at an upper portion of the valve body. In the flap valve supported by the valve, a lip-shaped projecting piece bent to the discharge pipe side is extended at the lower part of the valve body, and the valve body is opened by the action of the opening moment of the water flow .

Furthermore, the flap valve of the present invention is characterized in that it has a 30 ° to 60 ° bend angle before Symbol lip-shaped protrusion with respect to the valve body surface. Then, by reducing the thickness of the lip-shaped protrusion, a larger area of the protruding piece, large open moment by the water flow is one that acts on the valve body.

  As described in the means for solving the problems, the low-loss flap valve of the present invention has a lip-shaped projecting piece extending under the valve body to discharge water from the discharge pipe. A part of the abutment comes into contact with the protrusion. When the valve body receives the water flow, an opening moment acts on the valve body. And since the said protrusion is provided in the far position which opposes the valve axis | shaft of this valve body, an opening moment increases. Furthermore, since the lip-shaped projecting piece is bent toward the discharge pipe, a larger opening moment acts to increase the opening angle of the flap valve, and the loss factor can be reduced.

  Hereinafter, the low loss type flap valve concerning this invention is explained based on a drawing. In FIG. 1, a discharge pipe 5 is a pipe for draining from a pump facility or the like to a river 6 or the like, and has a discharge end 8 protruding from the land side through the embankment 7 to the river 6 side. A flap valve 1 is disposed at the discharge end 8 in order to prevent backflow to the discharge pipe 5 due to water increase when the water level of the river 6 rises. The flap valve 1 is connected to a flange 9 fixed to the discharge end 8 of the discharge pipe 5, and the flap valve 1 includes a valve body 3 and a swingable valve body 2.

  The low loss type flap valve of the present invention will be described in detail with reference to FIGS. FIG. 2 is a longitudinal sectional view of the flap valve 1, and FIG. 3 is a front view of the flap valve 1. A flange 10 is formed at the end (left side in FIG. 2) of the tubular valve body 3 having an inner diameter of φD mm, and the flange 10 and the flange 9 fixed to the discharge end 8 of the discharge pipe 5 are bolted.・ Fix with a nut (not shown). On the other hand, the other end portion (right side in FIG. 2) of the valve body 3 is inclined upward by a predetermined angle θ (5 to 10 degrees) with respect to the vertical line and opens upward. Further, two arms 11, 11 are fixed to the upper end portion of the valve body 3 at equal left and right positions.

  The valve body 2 has a disk shape that is substantially the same diameter as the outer diameter of the valve body 3, and reinforcing ribs 12 and 12 are fixed to the left and right positions in the vertical direction. Reinforcing plates 13 are fixed at equal positions in the horizontal direction. In FIG. 3, the reinforcing rib 12 and the reinforcing plate 13 are provided at two locations, respectively. However, the amount of use varies depending on the outer diameter of the valve body 3.

  The upper ends of the reinforcing ribs 12 and 12 extend from the outer periphery of the valve body 2, and the extended portions are further widened (to the left in FIG. 2). The widened portion is loosely inserted between the arms 11 and 11, and the valve body 2 is pivotally supported by the valve shaft 14 so as to be swingable. The valve body 2 is normally in close contact with the opening of the valve body 3 due to its own weight, and prevents backflow of water to the discharge pipe 5 when the river 6 is at a high water level. When the river 6 is at a low water level, the valve body 2 receives an opening moment due to the water flow from the discharge pipe 5, and moves upward with the valve shaft 14 as a fulcrum to be discharged into the river 6. The valve body 2 closes downward due to its own weight as the water flow from the discharge pipe 5 decreases, and comes into close contact with the opening of the valve body 3 when there is no water flow.

  However, even when the valve body 2 is opened, a closing moment due to its own weight always acts, causing a pressure loss with respect to the water flow. This pressure loss decreases as the opening angle of the valve body 2 increases, and increases as the opening angle decreases. Therefore, the larger the opening moment that acts when the valve body 2 is opened, the larger the opening angle and the smaller the pressure loss.

  A lip-shaped projecting piece 4 made of the same plate thickness as that of the valve body 2 or a slightly thinner plate thickness is extended below the valve body 2. Further, the length Lmm of the extended projecting piece 4 is inclined by the bending angle α in the direction of the valve body 3 (left direction in FIG. 2). Further, the extended projecting piece 4 has an angle of a width β. Since the direction of the acting force that the projecting piece 4 receives from the water flow is applied in a direction perpendicular to the projecting piece 4, the distance between the acting force and the valve shaft is increased, and a large opening moment is generated. Therefore, by providing the lip-shaped projecting piece 4 on the valve body 2, the resultant force of the opening moment acting on the valve body 2 and the projecting piece 4 acts as compared to the valve body 2 without the projecting piece 4. When the water flow is the same, the opening angle becomes large and the pressure loss can be reduced.

The bending angle α of the projecting piece 4 is 30 ° ≦ α ≦ 60 °, the length L is 0.05D ≦ L ≦ 0.2D, and the width β is 60 ° ≦ β ≦ 120 °. In order to act on the valve body 2, it is a very efficient range. If the length L and the width β are further increased to further increase the area of the projecting piece 4, a larger opening moment acts on the valve body 2, but its own weight is increased and the closing moment is also increased. Becomes worse. However, by reducing the plate thickness of the projecting piece 4 and reducing its own weight, the area of the projecting piece 4 can be increased, and a larger opening moment can be applied to the valve body 2 without increasing the closing moment. The pressure loss can be further reduced. Although the flap valve 1 described in detail above has a circular shape, the flap valve 1 of the present invention can be applied not only to a circular shape but also to various shapes such as a square shape. Further, the projecting piece 4 extending from the valve body 2 may be integrally formed with the valve body 2, welded, or fixed by bolts or the like according to the application and specifications.

Below, the analysis test performed in order to confirm the pressure loss reduction effect of the low loss type flap valve of this invention is demonstrated. As a test method, a general flap valve in which the projecting piece 4 is not provided on the valve body 2 and a flap valve according to the present invention in which the projecting piece 4 is provided on the valve body 2 were comparatively analyzed.
The specifications of the projecting piece 4 provided on the valve body 2 used in this analysis test are as follows.
・ Bending angle α = 45 °
・ Length L = 0.05D
・ Width β = 90 °
Hereinafter, Tables 1 to 6 show the analysis test results of the general flap valve and the flap valve of the present invention.

Closed moment due to dead weight of general flap valve and open moment due to water flow

Relationship between opening angle of general flap valve and loss factor

Relationship between flow rate and loss factor of general flap valve

The closing moment by the dead weight of the flap valve of the present invention and the opening moment by the water flow

Relationship between opening angle and loss factor of flap valve of the present invention

Relationship between flow velocity and loss factor of flap valve of the present invention

  From Tables 1 and 4, when comparing the opening angle of the general flap valve and the flap valve of the present invention at the speed of each water flow when the closing moment by its own weight and the opening moment by the water flow are balanced, the flow rate is 1 m / s. In the case of a general flap valve, the opening angle is 25 deg. In the flap valve of the present invention, the opening angle is 28 deg. Similarly, when the flow rate is 2 m / s, the opening angle of the general flap valve is 43 deg. The angle is 52.5 deg, and the opening angle of the flap valve of the present invention is larger at the same flow rate.

  Tables 2 and 5 show the opening angle and the loss factor at the outlet of the flap valve of a general flap valve and the flap valve of the present invention at a water flow velocity of 1 m / s. In the case of a general flap valve, when the flow rate is 1 m / s, the opening angle is 25 deg according to Table 1, and the outlet loss coefficient at this time is about 2.5. In the case of the flap valve of the present invention, when the flow rate is 1 m / s, the opening angle is 28 deg according to Table 4, the outlet loss coefficient is about 2.2, and the loss coefficient of the flap valve of the present invention is the same at the same flow rate. It is getting smaller.

  Tables 3 and 6 are tables summarizing loss factors of a general flap valve and the flap valve of the present invention at each flow rate. The effect of the present invention is not seen at a high flow rate of 3 m / s or higher, but the flap valve of the present invention is more common than a general flap valve at a flow rate of 1 to 2 m / s, which is usually most frequently used. It can be seen that the loss factor has been reduced and the results are good.

  The low-loss flap valve according to the present invention can not only perform installation and maintenance of equipment in the same way as a standard flap valve, but also allows a larger opening moment to act on the valve body only by water flow from the discharge pipe. As a result, the opening angle is increased, and flap valve loss can be reduced without having additional equipment such as balance weights and cylinders, which contributes to energy saving of equipment.

It is a schematic diagram of the low loss type flap valve which concerns on this invention. Similarly, it is a longitudinal cross-sectional view of a low-loss type flap valve according to the present invention. Similarly, it is a front view of the low loss type flap valve concerning the present invention.

Explanation of symbols

1 Flap valve 2 Valve body 3 Valve body 4 Projection piece 5 Discharge pipe 8 Discharge end α Bending angle

Claims (3)

A valve body (3) disposed at the discharge end (8) of the discharge pipe (5) and a valve body (2) for opening and closing the opening of the valve body (3) above the valve body (3) are swingable. In the flap valve (1) supported by the lip , a lip-shaped projecting piece (4) bent toward the discharge pipe (5 ) is extended to the lower part of the valve body (2), and the valve body is acted upon by the action of the opening moment of the water flow. (2) A low-loss type flap valve characterized by opening . The low-loss type flap valve according to claim 1 , wherein the bending angle (α) of the lip-shaped projecting piece (4) is 30 to 60 degrees with respect to the surface of the valve body (2). The low-loss type flap valve according to any one of claims 1 and 2 , wherein the lip-shaped projecting piece (4) is thinned to increase the area of the projecting piece (4). .