JP2000035138A - Intermediate torque reduction method of valve and its conduit structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce torque required for operation of a valve by using unbalanced torque working on a valve body. SOLUTION: Torque required for opening work of a valve body 14 is reduced by unbalanced torque working on the other side part 14b of the valve body 14 by generating channeling toward the other side part 14b of the valve body 14 revolving in a region on the downstream side by inserting a channeling generating body 15 in a channel on the upstream side of the valve body 14 against one side part 14a of the valve body 14 revolving in a region of the upstream side with a valve stem 13 as a border at the time of opening a butterfly valve arranged in the middle of a piping.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve arranged in a tap water pipe or the like, and more particularly to a method for reducing an intermediate torque of the valve and a pipe structure thereof.

[0002]

2. Description of the Related Art In a conventional butterfly valve, as shown in FIG. 4, a valve box 1 forms a part of a flow path of a pipeline system. It is opened and closed by an operating device or the like via the valve rod 3.

[0003] The rated torque required to open and close the valve body 2 in the butterfly valve is such that when the flow velocity of the fluid in the pipeline system is slow or when the diameter of the pipe is small, the seat of the valve body 2 and the valve box 1 are closed. The seating torque required for the sheet to abut compactly is set as a reference.

[0004]

In the opening and closing operation of the butterfly valve, one side 2a of the valve body 2 bounded by the valve rod 3 rotates in an upstream region bounded by the valve rod 3 so that the valve body is closed. 2 other side part 2b rotates in the area on the downstream side. At this time, the fluid F flowing through the pipe system acts on the valve body 2 as an external force, and the force acts on both sides of the valve body 2 with the valve rod 3 as a boundary. However, one side 2 of the valve body 2 that rotates to the upstream area
has a characteristic that the force acting on the valve body 2 is larger than the force acting on the other side portion 2b of the valve body 2 that rotates to the downstream region, and the difference in this force causes the valve body 2 to move in the closing direction. Acts as Ta. This force increases as the velocity of the fluid flowing through the pipeline increases or as the diameter of the pipe increases.

Therefore, at an intermediate opening degree during the opening operation, the fluid F exerts a force (unbalance torque) on the valve body 2, thereby increasing the torque Tb required to open the valve body 2, As for the torque required to open and close 2, the unbalance torque becomes more dominant than the seating torque as the velocity of the fluid flowing through the pipeline increases or as the diameter of the pipe increases.

However, when the rated torque of the operating device is set on the basis of the unbalance torque, there is a problem that the operating device becomes large. The present invention is to solve the above-mentioned problem, and reduces the torque required for operating the valve by using the unbalanced torque acting on the valve element. The purpose is to provide.

[0007]

According to a first aspect of the present invention, there is provided a method for reducing an intermediate torque of a valve, the method comprising the steps of: A valve element that rotates into the downstream area by inserting a drift generator into the flow path upstream of the valve element, facing one side of the valve element that rotates in the upstream area. The unbalanced torque acting on the other side of the valve body generates a drift toward the side and reduces the torque required for the opening operation of the valve body.

According to a second aspect of the present invention, there is provided a pipeline structure for reducing an intermediate torque of a valve in a pipeline system having a butterfly valve, which is located at a position upstream of a valve body and upstream of a valve stem. A drift generator is disposed opposite to one side of the valve body that rotates in the region, and the drift generator is provided so as to be able to move freely inside and outside the pipeline.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3, a butterfly valve 11 has a valve body 14 that rotates around an axis of a valve rod 13 inside a valve box 12, and the valve box 12 is connected to a pipe (not shown). A part of the path is formed, and the valve element 14 opens and closes between a fully closed position shown in FIG. 2 and a fully opened position shown in FIG. 3 by driving an operating device (not shown) connected to the valve rod 13.

On the upstream side of the valve body 14, a plate-shaped drift generator 15 is disposed, and the drift generator 15 is one of the valve bodies 14 that rotate to an upstream region bounded by the valve rod 13. Side 14
a. The drift generator 15 is provided in a slit portion 16 provided in the valve box 12 in a watertight manner by a sealing material (not shown), and is provided so as to be able to move back and forth over the inside and outside of the valve box 12. Note that the drift generator 15 may be disposed on a short pipe or the like separate from the valve box 12.

The operation of the above configuration will be described below. As shown in FIG. 2, when the valve element 14 is fully closed, the drift generator 15 is at the retracted position outside the valve box 12, and as shown in FIG. Fifteen
Is in a retracted position outside the valve box 12.

When the butterfly valve 11 is opened from the fully closed position, the drift generator 15 is arranged at a forward position protruding into the valve box 12, and in this state, a torque Tα required for the valve rod 13 by the operating device. And the valve body 14 is opened.

At this time, the fluid F flowing in the pipeline is deflected by the interference of the deflector 15 and deflected toward the other side portion 14b of the valve element 14 which rotates in the downstream region. .
This drift acts on the other side portion 14b of the valve body 14 as the unbalance torque Tβ, and the unbalance torque Tβ becomes larger than the torque Tγ acting on the one side portion 14a of the valve body 14, so that the valve body 14 The required torque Tα required for the opening operation is reduced.

When the butterfly valve 11 is closed from the fully open position, the drift generator 15 is retracted to the outside of the valve box 12, and a required torque Tα is applied to the valve rod 13 by the operating device.
The valve body 14 is closed. At this time, the torque Tγ acting on one side portion 14a of the valve element 14 is larger than the torque acting on the other side portion 14b, so that the valve 14 is closed.

[0015]

As described above, according to the present invention, a drift is generated by the drift generator toward the other side of the valve element which rotates in the downstream region, and the drift is generated on the other side of the valve element. By applying the unbalanced torque, the torque required for the opening operation of the valve body can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an intermediate opening of a butterfly valve according to an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a fully closed state of the butterfly valve.

FIG. 3 is a schematic diagram showing a fully opened state of the butterfly valve.

FIG. 4 is a schematic view showing a conventional butterfly valve.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Butterfly valve 12 Valve box 13 Valve rod 14 Valve element 15 Deviation generator 16 Slit part

Claims (2)

[Claims] When opening a butterfly valve disposed in the middle of a pipe, a flow upstream of the valve body is opposed to one side of a valve body that rotates to an upstream region bounded by a valve rod. The unbalanced torque acting on the other side of the valve body is generated by inserting a drift generator into the path and causing a drift toward the other side of the valve body which rotates in the downstream area, and the valve body is opened by the unbalanced torque. A method for reducing intermediate torque of a valve, characterized by reducing torque required for operation. 2. In a pipeline system having a butterfly valve,
A drift generator is arranged at a position upstream of the valve body, facing one side of the valve body that rotates in an upstream region bounded by the valve rod, and the drift generator is disposed inside and outside the pipeline. A pipe structure for reducing intermediate torque of a valve, which is provided so as to be retractable.