JPH04262179A - Power-driven valve - Google Patents

Abstract

PURPOSE:To enable a small electric motor to operate of the valve, shaft of a ball valve with low torque, wherein a valve ball and a valve seat member are strongly urged for intimate contact therebetween so as to provide a more sealable property between the two. CONSTITUTION:A valve ball 7 having a through hole 10 and annular valve seats 11, 12 for maintaining liquidtightness for a fluid in co-operation with the valve ball 7 are disposed within a valve casing having a fluid passage. A valve shaft 24 for rotating and operating the valve ball 7 is disposed in such a manner as to be airtightly passed through the valve casing. In this power- driven valve wherein this valve shaft 24 is driven by an actuator such as an electric motor, bimetals 21, 22 are disposed which urge the valve seats 11, 12 toward or against the valve ball 7. When the valve ball 7 is in an fully opened or fully closed condition, the bimetals 21, 22 are kept curved by non-energization to impart urging forces to the valve seats 11, 12. On the other hand, when the actuator is driven to cause the valve ball 7 to be partly opened or partly closed, the bimetals 21, 22 are displaced to become flat and act to impart reduced urging forces to the valve seats 11, 12.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a ball valve that is attached to a fluid piping to open and close a fluid passage to control the flow.
This invention relates to a motor-operated valve whose opening and closing operations are driven by an actuator such as an electric motor.

0002

[Prior art] Conventional general ball valves include
There is one disclosed in FIG. 1 of Publication No. 0-5833. The valve ball 7 placed inside the valve casing is rotated by a valve shaft 18 that passes through the valve casing in an airtight manner, and the ball 7 is placed on the inlet and outlet sides of the valve ball 7. In cooperation with the annular valve seats 12 and 13, the fluid passage is opened and closed in an airtight manner. In order to improve the sealing between the valve ball 7 and the annular valve seats 8 and 9, a disc spring 1 is placed in the direction of the valve ball 7.
2 and 13 are forcibly energized all the time. In the electric valve that is the subject of the present invention, the valve stem 18 is connected to an actuator such as an electric motor.
Therefore, the size of the actuator, that is, the driving torque, is determined by the valve ball 7 and valve seat 8.
This is determined by the sliding resistance with respect to 9.

0003

[Problem to be Solved by the Invention] In order to improve the sealing performance between the valve ball 7 and the valve seats 8 and 9 in the above ball valve, it is necessary to reduce the biasing force of the disc springs 12 and 13. It is well known that it is better to make it stronger, and it is widely practiced. however,
If the biasing force of disc springs 12 and 13 is increased, the valve ball 7
There is a problem in that the sliding resistance of the valve seats 8 and 9 becomes large and a large torque is required to rotate them. This ball valve does not pose a big problem when the valve stem 18 is operated manually as in the above publication, but if the valve stem is operated by an electric motor, the size of the electric motor will depend on the size of the valve stem. -A very large one is required in proportion to the sliding resistance between the valve seat and the valve seat.

[0004] Therefore, the technical problem of the present invention is to move the valve stem of a ball valve, which is strongly energized in order to improve the sealing performance between the valve ball and valve seat member, by using a small electric motor with low torque. The purpose is to make it possible to operate the system.

[0005]

[Means for Solving the Problems] The technical means of the present invention taken to solve the above technical problems includes a valve ball having a through hole in a valve casing having a fluid passage, and a valve ball having a through hole in a valve casing having a fluid passage. An annular valve seat is arranged to maintain fluid airtightness in cooperation with the ball, and a valve stem for rotating the valve ball is arranged to pass through the valve casing in an airtight manner. In valve stems that are driven to open and close by an actuator such as an electric motor, a bimetal is arranged to urge the valve seat toward the valve ball, and the bimetal is used to control the valve ball when it is in the open or closed state. When the valve ball is in the process of opening or closing when the actuator is driven, it is de-energized to keep it in a bent state and apply a biasing force to the valve seat, and when it is energized, it is flattened and the valve This acts to reduce the urging force on the seat.

[0006]

[Operation] The operation of the above technical means is as follows. When the valve ball is in the open or closed state, the bimetal is not energized and maintains its curved state to apply biasing force to the valve seat and maintain sealing with the valve ball. Next, an operation signal for opening/closing is sent to the actuator, and when the actuator is driven and the valve ball is in the process of opening or closing, the bimetal is flattened by energization and closes to the valve seat. As a result, the sliding resistance between the valve ball and the valve seat is reduced, so the valve shaft can be rotated with a small torque actuator.

[0007]

[Example] An example showing a specific example of the above-mentioned technical means will be described (see FIGS. 1 and 2). The electric valve of the present invention is composed of a ball valve section 1 and an electric actuator 2. First, the ball valve section 1 will be explained. The valve housing is formed of a main body 3 and end members 4 and 5 flanged to the main body 3,
It has an inlet 8, an outlet 9, and a valve chamber 6 inside. A valve ball 7 having a through hole 10 is rotatably arranged in the valve chamber 6. Valve seats 11 and 12 are arranged on the valve chamber 6 side of the inlet 8 and outlet 9, and disc springs 17 and 18 are arranged in the direction of the valve ball 7 via liners 15 and 16 to bias them. do. 13, 14 are valve seats 11, 12 and valve chamber 6
This is an O-ring to seal between the inner walls of the

There is a liner on the outside of the disc springs 17 and 18.
Bimetals 21 and 22 are placed through 19 and 20. When the temperature of the bimetals 21 and 22 rises due to energization, they become flat as shown in Figure 2 and the valve seat 11,
The biasing force applied to the valve ball 7 of 12 is reduced, and when the valve ball 7 is not energized, it curves as shown in FIG. 1 and biases the valve seats 11 and 12. Reference numbers 30 and 31 are gaskets.

A valve shaft insertion hole 23 that reaches the valve chamber 6 is provided in the upper part of the main body 3 . The valve shaft 24 is rotatably fitted into the fitting hole 23 from the outside, and its lower end passes through the valve ball 7 and fits into the support hole 41 on the opposite side. Also, the valve stem 24 is A
Connect with valve ball 7 at the keyway. The valve stem 24 is connected to the flange 2
5 is provided, and gaskets 26 and 27 are provided below the flange 25.
, 28 to maintain sealing performance, and fixed with an E ring 29.

The electric actuator 2 includes an electric motor 32, a reduction gear 33, a photocoupler 34, and a wiring board 35 constituting a control section to which other electronic components are attached. The rotating shaft 36 of the electric actuator 2 is connected by a joint 37. The rotational force of the electric motor 32 is reduced by a reduction gear 33 and transmitted to the rotating shaft 36, and then transmitted to the valve shaft 24 via a joint 37.
is rotated. A power line 3 is connected to the wiring board 35 from the outside.
8 and a signal line 39 for opening/closing signals are connected. Further, a power line 40 for supplying current is wired from the wiring board 35 to the bimetals 21 and 22. Furthermore, bimetal 21,
The timing of energizing 22 is controlled by a control section in the wiring board 35 based on a valve opening/closing signal based on a signal line 39. In other words, while the electric motor 32 is operating, the bimetal 21,2
When the electric motor 32 is in a stopped state, the bimetal is controlled not to be energized.

[0011] The operation will be explained. In Figure 1, the valve ball
When the valve 7 is in the open state, the bimetals 21 and 22 are de-energized, maintain a curved state, apply biasing force to the valve seats 11 and 12, and maintain sealing performance with the valve ball 7. Next, an operation signal for closing the valve is sent to the electric actuator 2, and at the same time as the valve shaft 24 rotates, the power line 40 is connected to the wiring board 35.
Electricity is applied to the bimetals 21 and 22 via When the bimetal is energized, its temperature rises and it becomes flattened, reducing the biasing force on the valve seat (the state shown in Figure 2).
. Therefore, when the actuator is driven and the valve ball 7 is in the process of opening or closing, the valve ball 7 and the valve seat 11
, 12 is reduced, the valve shaft 24 can be rotationally driven by an actuator with a small torque.

Although the above embodiment is an electric actuator, it can also be applied to a manual ball valve or an air-operated actuator.

[0013]

[Effects of the Invention] According to the present invention, the driving torque during the rotation operation of the valve ball is reduced, so the torque is lower than that in the past.
In other words, it is now possible to use a small actuator, making it possible to manufacture a small electric valve as a whole. Therefore, the current consumption of the electric motor is also reduced.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an electric valve according to an embodiment of the present invention, showing a state in which the bimetal is not energized.

FIG. 2 is a partial cross-sectional view of FIG. 1, showing a state in which the bimetal is energized.

[Explanation of symbols]

1 Ball valve part 2 Electric actuator 7 Valve ball 11,12 Valve seat 21, 22 Bimetal

Claims (1)

[Claims] [Claim 1] A valve ball having a through hole in a valve casing having a fluid passage, and an annular valve seat for maintaining fluid tightness in cooperation with the valve ball, The valve shaft for rotating the ball is arranged to pass through the valve casing in an airtight manner, and the valve shaft is driven to open and close by an actuator such as an electric motor. - When the valve ball is in the open or closed state, the bimetal maintains its curved state and applies a biasing force to the valve seat when the valve ball is in the open or closed state, and the actuator An electric valve that operates so that when the valve ball is in the process of opening or closing, it is energized to flatten the ball and reduce the force applied to the valve seat.