JPH07158750A - Ball valve - Google Patents

Abstract

PURPOSE:To provide a ball valve in which the relationship between the degree of valve opening and the rate of flow to be required to perform the rate-of-flow regulation is acquired using one ball valve element, wherein the relationship consists in two rate-of-flow characteristics, i.e., the linear proportional characteristic and equal ratio characteristic. CONSTITUTION:A ball valve is so structured as opened and closed by turning a ball valve element 3 having a through hole internally, wherein one of the openings of the through hole is shaped circular while the other opening has such a section as assuming a segment form in the rotating direction of the ball valve element 3. Therein the diameter of the circular opening 5a should be equal to the length of the segment-form opening 5b, and the section is shaped so that the following conditions are met simultaneously: 0.1D<=L<0.3D and 10<=theta in deg.<25, where D is length of the segment opening, L is length of the minor edge member of the segment, and theta is the inclining angle of the slope of segment in the rotational direction. Therein the mounting is made so that ball valve element is mounted as capable of rotating 90deg. in both directions left and right from the closed condition.

Description

Detailed Description of the Invention

[0001]

The present invention relates to water in various industries,
The present invention relates to a ball valve used for a fluid transportation piping line for oil, gas, chemicals, foods, etc. More specifically, it relates to a ball valve whose flow rate can be easily adjusted by changing an opening.

[0002]

2. Description of the Related Art A ball valve is a valve that can be opened and closed by rotating it by about 90 degrees and has a simple structure and is economically advantageous. However, since the flow rate changes rapidly depending on the opening, the flow rate is adjusted. It was unsuitable for use.

Various proposals have been made in the past for the purpose of preventing this sudden change in the flow rate, and one example of them has been disclosed in Japanese Utility Model Laid-Open No. 2-36667. The ball valve described in the publication is a valve that opens and closes by rotating a closing member having a through hole by approximately 90 degrees.
The cross-sectional shape of the outflow side opening of the through-hole is a substantially triangular shape or a long rectangular shape extending in the rotation direction of the closing member.

That is, by making the cross-sectional shape substantially triangular, the flow rate can be changed in a quadratic proportional manner according to the opening of the valve, and the cross-sectional shape can be changed to a substantially elongated rectangular shape. By doing so, the flow rate is linearly changed and adjusted according to the opening of the valve.

[0005]

However, it is necessary to prepare two closing members for adjusting the flow rate in case the transportation state of the fluid cannot be predicted by the ball valve or in case the transportation state is changed. It was causing an increase in expenses. Further, when the closing member is replaced if necessary, the valve must be disassembled, and there are problems such as suspension of fluid transportation and fluid scattering.

The present invention has been made in view of the above problems, and its purpose is to provide two flow rate characteristics required for flow rate control, that is, the relationship between the valve opening and the flow rate is substantially linear. It is an object of the present invention to provide a ball valve having the same proportional characteristic as that obtained by one ball valve body.

[0007]

The structure of the present invention for solving the above problems will be described with reference to FIGS. 1 and 2 showing an embodiment thereof.

The ball valve of the present invention is a ball valve in which the rotation of the spindle 4 causes the ball valve element 3 which engages with the spindle 4 and has a through hole 5 therein to rotate to open and close the valve. One opening 5 of the through hole 5
a (indicated by a dotted line) has a circular shape, and the other opening 5b has a cross-sectional shape that is substantially fan-shaped in the rotation direction of the ball valve element 3, and the diameter of the circular opening 5a and the fan-shaped opening 5b. The length of the fan-shaped opening is the same, the length of the fan-shaped opening is: D, the length of the fan-shaped short side is: L, and the inclination angle of the fan-shaped oblique side with respect to the rotation direction is θ: 0.1D≤L≤0.3D The cross-sectional shape is formed so that the relationship of θ ≦ 25 degrees is simultaneously established, and further, the ball valve element 3 is mounted so as to be rotatable by 90 degrees in the right direction and the left direction from the closed state. Is.

The cross-sectional shape of the fan-shaped opening 5b of the ball valve element 3 must be formed so as to satisfy the above two conditions at the same time. At the same time, it cannot be obtained accurately.

A more preferable range of the above two conditions is 0.
15D ≦ L ≦ 0.25D, 10 degrees ≦ θ ≦ 20 degrees,
By forming them within these ranges, the above two flow rate characteristics can be obtained with higher accuracy.

The material of the ball valve of the present invention may be plastic or metal and is not particularly limited. The direction of inflow and outflow of the fluid is not limited, and the fluid may be introduced from either side of the ball valve.
There is no difference in their regulation function.

[0012]

The operation of the present invention having the above structure will be described with reference to the ball valve shown in FIG. 1 (valve closed state).
The ball valve element 3 moves rightward (A arrow) via the spindle 4.
Since it has a structure capable of rotating 90 degrees to the left and 90 degrees to the left (arrow B), the fan-shaped opening 5b is
The flow rate can also be increased from the long side. When the ball valve element 3 is rotated 90 degrees to the right (A direction) from the state of FIG. 1, the fan-shaped opening 5b opens from the short side, and an equal ratio characteristic is obtained, and conversely to the left (B direction). 90 °), the fan-shaped opening opens from the long side, and a linear proportional characteristic is obtained.

When the fan-shaped opening 5b is formed in the direction opposite to the rotational direction, the relationship between the rotational direction and the characteristic is the opposite of the above.

[0014]

The present invention will be described in more detail with reference to the drawings showing the embodiments, but it goes without saying that the present invention is not limited to the embodiments.

FIG. 1 is a vertical cross-sectional view showing an embodiment of the ball valve of the present invention in a closed state (however, the ball valve element 3 is shown in a front view).

In the figure, reference numeral 1 denotes a valve body having a substantially hollow cylindrical shape, and a hollow cylindrical union 2 is screwed into the openings at both ends thereof. Reference numeral 6 is a body cap connected to a pipe or the like (not shown), which is detachably fixed to both ends of the valve body 1 via a union 2 by cap nuts 7 screwed onto the outer circumferences of both ends of the valve body 1. ing. In the valve body 1, a ball valve element 3 that engages with a spindle 4 and has a through hole 5 therein is sandwiched by a seat ring 8 mounted on a union 2, and the spindle 4 moves rightward (direction A). 90 to the left and to the left (direction B)
It is provided to be rotatable.

When the ball valve element 3 is rotated rightward, the through hole 5 has a circular opening 5a on the outlet flow passage 10 side,
The cross-sectional shape of the opening 5b on the side of the inlet channel 9 is generally fan-shaped in the rotation direction of the ball valve body 3, and the diameter of the circular opening 5a and the length D of the fan-shaped opening 5b are the same. Has been formed. It should be noted that when the ball valve element 3 is rotated leftward, the positional relationship described above is reversed.

In the present embodiment, the cross-sectional shape of the fan-shaped opening 5b is provided so that L = 0.22D and θ = 13.5 degrees. (See Figure 2)

The operation of the ball valve of this embodiment having the above construction will be described with reference to FIG. In the figure, since the inlet flow passage 9 and the outlet flow passage 10 are closed by the ball valve body 3, the flow of the fluid flowing from the inlet flow passage 9 is stopped and the valve is completely closed. Here, when the ball valve body 3 is rotated rightward (direction A) through the spindle 4 by an automatic control device or a manual operation, the fan-shaped opening 5 is formed.
Since b is opened from the short side, the flow rate can be increased and adjusted substantially equiproportionally to the valve opening. When it is further rotated, it rotates 90 degrees and becomes a fully opened state. (Fig. 3
reference)

On the other hand, when the ball valve element 3 is rotated to the left (arrow B) from the closed state, the fan-shaped opening 5b opens from the long side, so that the flow rate is almost linearly proportional to the valve opening. Can be increased and adjusted. When it is further rotated, it rotates 90 degrees and becomes a fully opened state.

With the above operation, two kinds of flow rate can be adjusted with one ball valve body. In other words, it is not necessary to prepare two types of closing members in case the transport state of the fluid cannot be predicted or the transport state is changed, and these two types of flow rate adjustments only change the rotation angle of the ball valve body. It can be selected easily, and complicated work such as disassembling the ball valve and replacing the closing member is unnecessary.

A caliber 80 having the structure shown in FIG.
A real flow test was conducted under the following conditions using a ball valve with A, D = 68.5 mm, L = 15 mm, and θ = 13.5 degrees.
Further, the cross-sectional shape out of the above condition range (aperture 80A, D = 68.5 mm, L = 0 mm, θ = 10 degrees) was also performed at the same time. [Conditions] Fluid… water Fluid temperature… 25 ℃ Pressure difference before and after the valve… 0.5 kgf / cm ²

[0023]

[Table 1]

The results are shown in FIG. 4 and Table 1. Figure 4
In the figure, the opening is shown as 100% when rotated 90 degrees to the right from the closed state (0%), and the opening is shown as -100% when rotated 90 degrees to the left. Also curve A
1 and A2 represent the products of this example, and B1 and B2 represent those whose cross-sectional shape deviates from the above condition range.

Table 1 shows the openings 30 to 100 in FIG.
% (-30 to -100%) straight line (dotted line display) (a
(Corresponding to 1, b1, a2, b2) maximum error (%)
(Corresponding to C1, D1, C2, D2) is shown.

As can be seen from FIG. 4 and Table 1, in the product of this embodiment, it is 9 in the rightward direction and 9 in the leftward direction from the closed state.
By rotating it by 0 degree, the maximum error is reduced to + 11% in the case of the constant ratio characteristic and -5.5% in the case of the linear proportional characteristic, and both characteristics are obtained with high accuracy.

On the other hand, in the case where the condition is out of the above range, the maximum error is as large as + 19.5% in the case of the constant ratio characteristic and + 24% in the case of the first-order proportional characteristic, and sufficient performance cannot be obtained.

[0028]

When the ball valve of the present invention described above is used, the following effects are obtained. Two flow rate characteristics required for flow rate control, that is, one in which the relationship between the valve opening and the flow rate is the linear proportional characteristic and the one in which the flow rate characteristic is the proportional characteristic are obtained with one ball valve element. Therefore, it is possible to reduce the initial cost and maintenance cost because it is not necessary to prepare two kinds of closing members in case the transport state of the fluid cannot be predicted or the transport state is changed. The above two kinds of flow rate adjustment can be easily obtained only by changing the rotation direction of the ball valve element. Therefore, the transportation of the fluid is stopped,
This saves labor such as disassembling the ball valve for replacing the closing member, thus greatly improving work efficiency. Since it is not necessary to replace the closing member, there is no problem of chemical liquid scattering and the like, the safety of the worker is secured, and environmental pollution can be prevented.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view including a partial front view showing an embodiment of a ball valve of the present invention.

FIG. 2 is a front view of the ball valve body in FIG. 1 on the side of a fan-shaped opening.

3 is a longitudinal sectional view showing a fully opened state of the ball valve in FIG.

FIG. 4 is a flow rate characteristic diagram showing a result of an actual flow test.

[Explanation of symbols]

 1 ... Ball valve body 2 ... Union 3 ... Ball valve body 4 ... Spindle 5 ... Through hole 5a ... Circular opening 5b ... Fan-shaped opening 6 ... Body cap 7 ... Cap nut 8 ... Seat ring 9 ... Inlet channel 10 ... Outlet Channel

Claims (1)

[Claims] 1. A ball valve for engaging and disengaging a spindle to rotate a ball valve body having a through hole therein to open and close the valve, wherein one opening of the through hole is provided. The cross-sectional shape of the other opening is circular in the direction of rotation in the direction of rotation of the ball valve body, and the diameter of the circular opening is equal to the length of the fan-shaped opening. Length: D Length of short side of fan shape: L Inclination angle of oblique side of fan shape with respect to rotation direction: When θ: 0.1D ≦ L ≦ 0.3D 10 degrees ≦ θ ≦ 25 degrees is satisfied at the same time. A ball valve having a cross-sectional shape, wherein the ball valve body is mounted so as to be rotatable 90 degrees to the right and left from the closed state.