JPS60208672A - Ball valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to earthenware, and particularly to earthenware having an anti-yavitation mechanism. This type of anti-cavitation mechanism generally has a plurality of radially extending cavities formed in the downstream flange of the dotan, which allow air to flow into the fluid flow passage from outside the valve to prevent the valve from flowing. It has a check valve mechanism to prevent cavitation in the downstream fluid.

Dotans generally include a cylindrical housing with a fluid passageway through which a generally spherical valve closure member is rotatably mounted. The closure member has a cylindrical opening corresponding to a cylindrical passageway passing through the valve housing, and the fluid passageway can be rotated to a closed position in which the closure member closes the valve housing. Radially extending flanges are typically provided at the upstream and downstream ends of the housing for connecting to fluid conduits.

When the valve closure member closes a portion of the fluid passageway, the cross-sectional area of this passageway is reduced. This closure increases fluid velocity within the area of the closure member diameter. This increase in velocity reduces the fluid pressure within this area, creating multiple steam pockets within this area. These pockets expand in volume as the liquid evaporates, and when the surrounding liquid pressure becomes greater than the vapor pressure within the pocket, these pockets collapse. This phenomenon occurs repeatedly and also exerts significant forces on the valve closure member and housing as well as adjacent conduits. This is what is called cavitation, which damages valves and pipes.

One conventional method for reducing the occurrence of cavitation described above is to inject high pressure gas into the valve closing member. The valve closure member is provided with a plurality of openings downstream thereof to increase pressure within the flow passageway and prevent the formation of steam pockets.

This method is expensive to manufacture and expensive to maintain in operation.

Therefore, it is an object of the present invention to provide a clay mat having an effective anti-cavitation mechanism.

SUMMARY OF THE INVENTION The present invention has a generally cylindrical valve body with radial flanges near its ends. A generally spherical closing member is rotatably mounted within the valve body. The closure member has a cylindrical opening corresponding to a cylindrical fluid passage through the valve body, allowing fluid to pass therethrough when the closure member is in a fully open state. When the closure member is rotated to the closed position, the valve body closes and closes the fluid flow passageway.

The cylindrical valve body described above has a flange located downstream of the valve and provided with a plurality of radially extending cavities. These cavities extend from the radially innermost part of the flange adjacent to the flow passageway to the radially outermost part of the flange. These cavities are provided with check valves.

It allows air to flow into the flow passage from outside the valve and prevents fluid from flowing out from the cavity. It is desirable that these check valves be provided so as not to interfere with valve operation.

A ring is also provided adjacent to the innermost portion of the valve.

The ring has a cross-sectional shape forming a slot operatively connecting the cavities within the flange. The ring also has a plurality of orifices that direct airflow from outside the valve body into the fluid flow passageway. It is desirable that these orifices be inclined at an acute angle with respect to the normal fluid flow direction so as to obstruct the external flow of the fluid.

Specifically, the valve of the present invention includes a cylindrical valve body having a passageway through which fluid flows, and a closing member rotatably mounted within the valve body, the closing member opening the passageway by this operation. forming a seal that closes to prevent fluid flow;
The cylindrical valve body has a radially extending flange near one end thereof, the flange having a plurality of radially extending cavities, the cavities being at the innermost radially end of the flange adjacent the fluid passageway. and extending from the flange to the outermost part of the flange, each cavity being provided with a check valve which prevents fluid flow through the cavity from the fluid passageway but admits air from the outside into the passageway through the cavity. It has the function of preventing the formation of a pressure pocket of 1 atmosphere or less in the fluid flowing in and forward of the valve.

As mentioned above, cavitation problems occur when the valve closure member partially closes the fluid passageway. When liquid passes through the passageway when the closure member is in the above position, the flow rate increases due to the reduction in the flow area. This increase in flow rate reduces the pressure within the fluid immediately behind the closure member. This pressure drop creates steam pockets within the fluid. The expansion of these pockets and their collapse due to the surrounding liquid pressure exceeding this vapor pressure is the cavitation effect. The valve of the present invention opens the check valve in the downstream flange cavity whenever the pressure in the flow passage decreases to prevent the formation of steam pockets. Opening of the check valve allows air to flow in from outside, thus preventing the formation of steam pockets and cavitation effects mentioned above.

Good 1 A generally cylindrical valve body 10 is shown in FIG.

The valve body 10 has an upstream portion 12 and a downstream portion 14, both of which have a plurality of threaded bolts 16 therethrough. Valve closure member 18 is generally spherical in shape and is rotatably mounted within the valve body by a shaft 20 that extends from valve body 10 . An operating handle (not shown) is typically attached to one end of the shaft 20. A plurality of resilient members 22 are disposed within the valve body 10 outside the normal diameters of the upstream fluid passageway 24 and the downstream fluid passageway 26. When the valve closure member 18 is rotated to the closed position, a corresponding corner of the closure member 18 contacts each resilient member 22 .

A seal is formed for the upstream fluid passageway 24 and the downstream fluid passageway 26.

The upstream portion 12 of the valve body 10 has a radially extending flange 28.
, which flange is attached to the conduit (FIG. 2) by known means such as threaded bolts and nuts.

The downstream section 14 includes a radially extending flange 30 that includes a plurality of cavities 32 adjacent to the downstream fluid passageway 26 extending from the radially outermost to the innermost portion of the cavities 32 . A ring 62 is arranged adjacent to the inner part. Details of this embodiment of the invention are shown in FIG.

FIG. 2 is a detailed cross-sectional view of a portion of the downstream flange 30 of one embodiment of the present invention. Cavity 32 extends from the radially outermost portion of flange 300 adjacent to fluid passageway 26 to the innermost portion of the flange. The outer diameter of the ring 34 is 7 ranks 300
The diameter of the fluid passage 26 at the centermost part in the radial direction and 11 are the same,
This ring is attached to the flange 30 with threaded bolts 36 or the like. The ring 34 has a thin cross section and the valve closing member 18
As shown in the figure, an annular slot 38 is formed at the inner end of the passage 26 of the cavity 32, where the head loss is extremely small when the valve is in the fully open position. The ring 34 is provided with a flow passage within the passage 26 and an oriwis 40 at an acute angle. Although the ring 34 is provided with a plurality of orifices 40, these orifices do not necessarily have to be located adjacent to each cavity 32. Also, the number of orifices 40 is generally three or four times greater than the number of cavities 32.

A check valve 50 is connected to the radially outermost portion of the cavity 32 by a nipple 53 . The check valve 50 has a control spring 52
The spring causes the check valve to act as a vacuum control valve.

When an underpressure steam pocket develops in the fluid passageway 26, this pressure compresses the spring 52, allowing air to flow from the outside into the check valve 50. This inflow of air into passageway 26 through cavity 32 and orifice 40 suppresses the formation of steam pockets within passageway 26.

FIG. 3 shows another embodiment of the check valve-cavity of the present invention. A check valve 50 is connected to the cavity 30 provided in the flange 30 of this embodiment as in FIG. 2. However, the innermost end of the cavity 32 in the radial direction is -m from the innermost end of the flange 30. A channel ring 62 is secured to the innermost portion of the flange 30 to form a slot 66 so that the cavities 32 all connect at their innermost ends. The slot 62 is provided with a plurality of orifices 60 which function similarly to the orifices 40 described in the embodiment of FIG.

[Brief explanation of the drawing]

Fig. 1 is a side cross-sectional view of an embodiment of the clay mat according to the present invention; Fig. 2 is a partial sectional view of an embodiment of the flange and check valve;
FIG. 3 is a partial cross-sectional view of another embodiment of the flange and check valve.
downstream part, 16... bolt, 18... valve closing member, 2
0... Shaft, 22... Elastic member, 24... Upstream fluid passage, 26... Downstream fluid passage, 28... Flange,
32...Cavity, 34...Ring, 40...
...Orifice, 50...Check valve

Claims (1)

Claims: (11) A cylindrical valve body having a passageway through which fluid flows; a closing member mounted within the valve body that is rotatably operated to form a seal that prevents fluid flow within the passageway of the valve body. 72 radial angles provided near one end of the valve body;
It has a plurality of cavities extending in the radial direction, and the cavities are provided in the above-mentioned 72 holes adjacent to the fluid flow passage and extending from the radially innermost part of the flange to the radially outermost part of the flange, and each of the above cavities. A check valve prevents fluid from exiting the fluid passageway through a cavity, but allows air to enter the fluid passageway from the outside through the cavity, creating a pocket of low pressure in the exiting fluid flowing beyond the valve. The above-mentioned check valve prevents the formation of. Dotan including. (2) The ring device described in item 1 above includes a ring device having a plurality of orifices arranged at equal intervals on nine circumferences and forming an acute angle with the fluid passage, and the ring device includes a groove hole that fluidly connects each cavity. Dotan has a shape arrangement that forms a . (3) In the Dotan described in paragraph 1 above, each reverse valve is connected to each cavity so as not to interfere with valve operation. (4) In the Dotan described in Paragraph 2 above, a ring device The dotan has a thin cross-sectional shape so that the head loss is minimized when the valve is fully opened.