JPH0229324Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a valve body for a butterfly valve, and the valve body can be widely used to reduce unbalanced torque received from fluid flowing inside the valve. .

(Prior art) As shown in Figure 3, butterfly valves that have been widely used in industry have a
The pressure distribution 2 on the valve body (valve plate) 1 is distributed according to Bernoulli's theorem, and as can be seen from the situation of this pressure distribution 2, it acts on the valve body surface mainly due to the difference in dynamic pressure of the fluid. The fluid pressure on both the front and back surfaces is not symmetrical with respect to the valve shaft, and due to this asymmetric pressure distribution difference, a force F in the direction of closing the valve body is always acting on the valve body 1 on both the front and back sides. .

Therefore, when opening the valve body 1, a large force is required to overcome the unbalanced torque caused by the force F.

(Problems to be solved by the invention) In the above-mentioned conventional butterfly valve, when opening the valve body 1, a force is required to overcome the above-mentioned torque.
For this reason, a large drive unit is required, especially in the case of an automatically operated valve, resulting in a waste of energy. Moreover, this tendency becomes more pronounced as the diameter of the valve becomes larger. Furthermore, in control valves that control fluid, this unbalanced torque causes problems such as deviations in hysteresis when the drive unit opens and closes, which has negative effects such as reduced control performance. Ta.

(Means for Solving the Problems) In order to solve the above-mentioned problems of the prior art, the present invention provides a part of the valve body of a butterfly valve with a structure that cancels out the unbalanced torque that the valve body receives from the fluid. It is characterized by the fact that the blades that generate lift are mounted separately and away from the valve body.

In practice, it is desirable that the blades be attached to the surface of the fluid inflow side that is inclined rearward with respect to the flow when the valve is opened, with a fluid passage interval between them.

(Function) Since the present invention is configured as described above, when the valve is opened, especially at an intermediate opening, the lift force acting on the blade attached to the surface of the valve body on the side that is inclined rearward with respect to the flow is Due to the difference in pressure distribution mainly based on the difference in dynamic pressure of the fluid, which acts on both the front and back surfaces of the valve body due to the flow of fluid, this force is generated in a direction that opposes the force acting in the direction of closing the valve body. Therefore, the unbalanced torque generated by the force acting in the direction of closing the valve body is reduced.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view showing one embodiment of the valve body of the butterfly valve of the present invention, and FIG. 2 is an explanatory view showing its operating state. In the figure, the valve body 11 has a predetermined portion that becomes a fluid passage 13 on a surface 11a which is the fluid inflow side and which is inclined toward the rear, i.e., the downstream side with respect to the flow when the valve is opened, as shown in FIG. Wings 12 are installed at intervals, and the wings 12 act on both the front and back surfaces of the valve body 11 due to the flow of fluid, and act on the valve body 11 by a pressure distribution difference mainly based on a difference in dynamic pressure of the fluid. The cross-sectional shape is formed into an airfoil shape so as to generate a lift force L in a direction to cancel the force F acting in the closing direction, that is, in the direction to open the valve, that is, toward the valve body 11 side in the figure. The shape of the airfoil, the size of the airfoil, the mounting position on the valve body, etc. can be changed as appropriate, and by doing so, it is possible to create a butterfly valve with extremely low unbalance torque. In addition, in the figure, 14 indicates a leg piece to which the wing 12 is attached.

Next, to explain the operation, as shown in FIG. 2, when the valve body 11 is operating at an intermediate opening degree, the flow in the direction of the arrow passing through the valve body 11 causes the surface of the valve body 11 to change. The back side, that is, both the inflow side and the outflow side, exhibits a pressure distribution 2 as shown in FIG. F acts, and a moment in the direction of closing the valve body 11 is exerted by these forces F and F.

On the other hand, the flow 15 passing through the rearwardly inclined surface 11a on the inflow side of the valve body 11 flows between the lower surface of the blade 12 formed in the airfoil shape in cross section and the upper surface of the valve body 1.
As is well known, when passing through the passage 13 formed between the blade 12 and the valve body 1, a lift force L is generated upward from below the blade 12, that is, towards the valve body 11. However, this lifting force L gives a moment in the opposite direction to the moment caused by the force F, that is, in the direction of opening the valve body 11, so it cancels out the moment acting in the valve closing direction and causes a force to be generated on the valve plate. This makes it possible to reduce unbalanced torque.

In addition, the blade in the present invention is attached to the surface 11b of the valve body inclined toward the upstream side by inverting the airfoil shape of the above-mentioned embodiment, so as to generate a lift force in the direction away from the valve body, that is, in the valve opening direction. It is also possible to configure

(Effects of the invention) As described above, according to the invention, wings that generate lift in a direction that cancels out the unbalanced torque that the valve element receives from the fluid are attached to a part of the valve element of the butterfly valve. By installing the valves at predetermined intervals, the unbalanced torque caused by the fluid acting in the closing direction on the valve body that is opened at an intermediate opening degree is offset by the lift force acting on the blades attached to the valve body. , the unbalanced torque described above can be reduced.

Therefore, the drive section can be downsized and energy-saving, and when the butterfly valve is used as a control valve, its controllability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the valve body of the butterfly valve of the present invention, FIG. 2 is an explanatory view showing its operating state, and FIG. 3 is an explanatory view showing the operating state of a conventional butterfly valve. . 11... Valve body, 12... Wings, 13... Fluid passage, F... Force acting on the valve body due to pressure distribution difference, L...
...Lift force.

Claims (1)

[Claims for Utility Model Registration] 1. A butterfly valve is characterized in that wings that generate a lift force in a direction that cancels out the unbalanced torque that the valve body receives from the fluid are attached to a part of the valve body away from the valve body. Valve body of butterfly valve. 2. The blade is attached to the surface of the fluid inflow side that is inclined rearward with respect to the flow when the valve is opened, with a fluid passage interval between them. Valve body of butterfly valve.