JPH0218464B2 - - 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 body 1 having compartments 3 and 4 that are partitioned into upper and lower parts by a partition wall 2, and an inlet on each side of each compartment 3 and 4. 5a and outlet 5b are open. 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 C _v 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 is arranged so that one window of the cage faces the inlet, and the flow path formed by the window converges at a position offset from the axis of the cage. The present invention provides a cage valve that can increase the capacity of the valve with an extremely simple structure of sloping the opening side edge. 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. Reference numeral 11 indicates the opening side edge in the direction parallel to the axis among the opening edges forming the four windows 6a to 6d opened in the peripheral wall of the cage 7, and 12 indicates the opening side edge in the direction parallel to the axis.
This is a flow path from a to the cage 7. cage 7
is arranged so that one window 6a among the windows 6a to 6d faces the flow path 12.

The opening side edges 11, 11..., the flow paths 13, 13... formed by the windows 6a to 6d converge at a point O at a position shifted laterally by a distance E from the axis of the cage 7, as shown by the chain line. I'm inclined to. That is, the windows 6a to 6d form a thick cage 7.
The flow paths 13, 13...
... can be formed, and in this embodiment, the opening side edges 11, 11 ... have a spiral-wound curve whose surface radiates counterclockwise in eight directions when viewed from above, centering on point O. It is formed into a curved surface that follows. In other words, the flow paths 13, 13... converge so as to rotate clockwise.

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
It flows through the flow path 12, passes through the flow paths 13, 13, . . . formed by the windows 6a to 6d, and flows into the cage 7.

When passing through the flow channels 13, 13..., the fluid is guided by the opening side edges 11, 11... so as to turn clockwise. Naturally, the flow rate of the fluid flowing in from each of the windows 6a to 6d is the largest from the window 6a facing the flow path 12, and moreover, the fluid flowing in from this window 6a flows into the flow path 13 formed by the window 6a. Since the fluid converges at point O, which is offset from the axis of the cage 7, the change in the guided direction is smaller than that of the fluid flowing in from the other windows 6b to 6d. Therefore, a spiral flow is formed in the cage 7 in which the fluid flowing in from the window 6a mainly swirls efficiently in a clockwise direction. The circumferential velocity of this spiral flow increases as it approaches the center, and the pressure naturally decreases, so the fluid from the windows 6b to 6d also flows along this spiral flow. Further, since the pressure is further lower near the center, the pressure difference between the cage 7 and the external pressure causes the cage 7 to be swept downstream. That is, the center is the cage 7
The air will be sucked towards the circular opening at the bottom of the screen.

Therefore, the fluids passing through this cage valve are prevented from violently colliding with each other as in the conventional case, and since the flow is not disturbed by this collision, the fluid flows in a smoother streamline than in the conventional case. 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.

In addition, in the above embodiment, the opening side edges 11, 1
1... has been described as being formed on a curved surface, but the present invention is not limited to this, and it goes without saying that a flat surface obtained by averaging the curved surface may be used. Any shape may be used as long as the flow channels 13, 13, . . . are converged at a position offset from the axis of the cage 7. Also window 6
Examples of the opening shapes of a to 6d include rectangular shapes, etc.
Of course, any shape that provides the required flow characteristics can be applied.

〔Effect of the invention〕

As explained above, according to the present invention, one window of the cage is arranged to face the flow path from the inlet, and the flow path formed by the window converges at the opening side edge of the window at a position offset from the axis of the cage. By slanting the cage in this way, the flow inside the cage can be efficiently guided so that the fluid flowing in through the one window swirls in a spiral shape, and can prevent them from colliding with each other.

Therefore, since the speed of fluid passing through the cage valve can be increased, there is an effect that the capacity of the valve can be increased.

[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, 1
3...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 cage is arranged such that one of the windows faces the flow path from the inlet to the cage. A cage valve characterized in that the opening side edges of these windows are inclined so that the flow path formed by these windows converges at a position laterally offset from the axis of the cage.