JPH0218465B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cage valve equipped with a cage having windows in its peripheral wall.

[Prior art]

Generally, control valves also start and stop the flow, but
Since the main purpose is to change the flow rate, it is necessary to have a certain relationship between the displacement of the movable part and the flow rate, that is, a flow rate characteristic. For this reason, cage valves are widely used as control valves because they can change the flow rate characteristics to the desired value by changing the shape of the window provided in the cage, are resistant to vibrations, and operate smoothly even at high differential pressures.

As shown in FIGS. 1 and 2, the conventional cage valve has a valve main body 1 having compartments 3 and 4 that are partitioned vertically by a partition wall 2, and an inlet 5a on both sides of each compartment 3 and 4, respectively. and the outlet 5b is opened. On the partition wall 2 of the valve body 1, a cylindrical cage 7 having a plurality of windows 6a to 6d on the peripheral wall is provided with a lid body 8.
Fixed by A plug 10 supported by a valve shaft 9 is inserted into the cage 7 so as to be movable up and down, and the plug 10 is raised and lowered by the valve shaft 9 to increase and decrease the opening area of the windows 6a to 6d to adjust the flow rate. It is composed of

However, in conventional cage valves of this type, the flow rate per unit time, that is, the capacity of the valve, is
There was a problem that the _CV value was limited. This is because the windows 6a to 6d of the cage 7 are provided radially from the axis of the cage 7, and as a result, fluid flows centripetally into the cage 7 as shown by the arrows. For this reason, the fluids collide violently near the center of the cage 7, and the fluid flow is greatly disturbed, which affects the flow velocity of the fluid passing through the cage valve.

[Summary of the invention]

The present invention was developed in view of the above circumstances, and has an extremely simple configuration in which the opening side edge of the window of the cage is inclined in a certain direction, and the cage is disposed offset from the center of the valve body. The present invention provides a cage valve that can increase the capacity of the cage. Hereinafter, its configuration and the like will be explained in detail with reference to embodiments shown in the drawings.

〔Example〕

FIG. 3 is a cross-sectional view showing a cage valve according to the present invention, and FIG. 4 is a longitudinal cross-sectional view. In these figures, the same or equivalent members as shown in FIGS. 1 and 2 are designated by the same reference numerals. , and its explanation will be omitted. 11 are four windows 6a~ opened at equal intervals.
Among the opening edges forming 6d, these opening side edges 11, 11...
is set to be inclined in a constant direction with respect to a plane that includes the axis of the cylindrical cage 7 and extends in the radial direction, and in this embodiment, is inclined counterclockwise when viewed from above. In other words, the windows 6a to 6d of the cage 7
is opened so as to face a surface in contact with the outer peripheral surface of the cage 7 in a direction inclined clockwise when viewed from above. These opening side edges 11, 11... are provided in the thick cage 7, so they have width in the direction of fluid flow, and guide the fluid flowing into the valve body 1 along its surface. Can be done. That is, the opening side edges 11, 11, . . . are averagely inclined at such an angle that the fluid flowing into the cage 7 through the windows 6a to 6d changes its flow and swirls in a clockwise spiral. The shape is preferably a curved surface along which a spiral curve follows or a plane close to it, and may be either a plane or a curved surface as long as it has an average inclination.

The cage 7 is arranged so that its axis is shifted laterally by a distance E from the center of the valve body 1, that is, at a position eccentric to the valve body 1. In other words, the fixing hole for fixing the cage 7, which was conventionally drilled in the center, is bored in the valve body 1 offset from the center. Therefore, in the flow path 12 formed by the outer peripheral wall of the cage 7 and the inner peripheral wall of the valve body 1, the flow path 12a through which the fluid flows clockwise is larger than the flow path 12b through which the fluid flows counterclockwise. Moreover, these channels 12a and 12b are formed so that their cross sections become gradually narrower in the circumferential direction in which the fluid flows.

In the cage valve configured in this way, the fluid that flows into the compartment 3 of the valve body 1 from the inlet 5a is
Windows 6 are guided along the outer circumferential wall of the cage 7 on both sides of the cage 7 and are substantially opposed to the flow direction.
It flows into the cage 7 from a and 6b. At this time, since the cage 7 is eccentric with respect to the valve body 1, more fluid guided to both sides of the cage 7 flows into the large passage 12a. The fluid flowing into these channels 12a and 12b is guided toward the cage 7 by the inner circumferential wall of the valve body 1 while rotating clockwise or counterclockwise, respectively, and smoothly flows into the cage 7 through the windows 6c and 6d. In particular, the fluid in the flow path 12a flows in very smoothly since the swirling direction and the direction of inflow into the cage 7 are the same clockwise direction. The fluid flowing into the cage 7 is guided clockwise by the opening side edges 11, 11, . . . and flows in a spiral manner inside the cage 7 along the inner peripheral wall surface. Since the peripheral speed of this flow increases as it approaches the center, the pressure naturally decreases near the center, and the cage 7
is pushed downstream due to the pressure difference between the external pressure and the external pressure. That is, the center is attracted toward the lower circular opening of the cage 7.

Therefore, the fluid passing through this cage valve is prevented from violently colliding with each other in the cage 7 as in the conventional case, and there is no flow disturbance due to this collision, and moreover, the fluid flows smoothly into the cage 7. , it draws smoother streamlines than before. As a result, energy loss can be reduced and the speed of fluid passing through the cage valve can be made faster than in the past.

It goes without saying that the openings of the windows 6a to 6d may have any shape, such as a rectangular shape, that can provide the desired flow characteristics.

〔Effect of the invention〕

As explained above, according to the present invention, the opening side edge of the window of the cage is inclined in a certain direction, and this cage is shifted from the center of the valve body, so that the fluid flows smoothly into the cage and swirls in a spiral shape. We can guide you as follows.

Therefore, since it is possible to prevent the fluids from colliding with each other and to increase the speed of passage through the cage valve, there is an effect that the capacity of the valve can be increased.
Further, since the valve body may be of a conventional shape and bored with the fixing hole of the cage offset from the center, there is an advantage that conventional parts can be used.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view showing a conventional cage valve;
3 is a cross-sectional view showing a cage valve according to the present invention, and FIG. 4 is a vertical cross-sectional view. 1...Valve body, 5a...Inlet, 6a-6d...Window, 7
...Cage, 11...Opening side edge, 12...Flow path.

Claims (1)

[Claims] 1. In a cage valve equipped with a cylindrical cage having a plurality of windows on the peripheral wall and fixed to the valve body, the opening side edge of the window is inclined in a certain direction, and the cage is arranged so that its axis is aligned with the valve body. A cage valve characterized in that it is arranged so as to be offset laterally from the center of the cage.