JPS5817274A - Gas/oil pressure type actuator for valve - Google Patents

Abstract

PURPOSE:To prevent an actuator from being broken due to an overload by cutting off a pipe line with a pressure cut-off valve when the gas pressure in the pipe line exceeds a certain value so that the output of the actuator will not exceed the design allowable output. CONSTITUTION:As the load of a valve 15 is increased due to some influences during the operation exceeding its rating, the output of an actuator is correspondingly increased, but when the gas pressure in a pipe line 23 reaches a preset pressure, a pressure cut-off valve 13 normally set at an open position is switched to a close position, cutting off the pipe line 23, thus the gas feed to a tank 8a is stopped. Accordingly, the output of the actuator is made a proper output corresponding to the required power of the valve irrespective of a further increased pressure in the pipe line, thereby preventing an overload of the actuator.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas/hydraulic actuator for a valve that uses gas pressure in a pipeline to hydraulically drive a valve.

The output of this type of actuator increases in proportion to the gas pressure in the pipeline, so a special shark key is used to prevent damage due to overload, and if the actuator output exceeds the design allowable output, ,
It is common practice to disconnect the shear key that transmits its output to the valve stem. However, it is difficult to cut the shear key when it actually overloads, and if the shear key is not cut and gradually deforms, the valve opening will be adjusted by the amount of deformation relative to the output opening of the actuator. This causes the fatal problem that when the pipe is fully opened, the cleaning pipe cannot pass through the pipe, and when it is fully closed, the seal position of the valve is misaligned and the valve is not properly sealed. Moreover, in addition to the necessity of using a special key, there is also the problem that quality control costs are incurred in order to eliminate variations in the strength of the key material.

The present invention solves the above problems and provides a gas≠pressure type actuator for valves that can suppress the output to an appropriate value corresponding to the valve required torque and prevent damage to the entire valve even if the pressure in the pipeline increases significantly. 1. The purpose of the present invention is to provide a galvanic pressure actuator for pulp.
Consists of a pair of gas oil tanks, a double-acting cylinder, and
In an extraction type actuator, the oil in one tank is pressurized by the gas pressure in the pipeline, and the pressure oil operates the cylinder to drive the valve installed in the pipeline. The present invention is characterized in that a pressure cutoff valve is disposed in a conduit through which gas in the line is introduced into the pair of gas oil tanks.

In a preferred embodiment, two double-acting cylinders are connected in series, the output of which is transmitted to the valve via a rocking member that engages a piston rod connecting the pistons of both cylinders. For simplicity, one double-acting cylinder is employed.

Further, a pipe line that introduces gas in the pipeline to a pair of gas oil tanks is divided into two via a pair of electromagnetic valves or other switching valves, and a pressure cutoff valve is provided in the pipe line before branching. Depending on the case, pressure cutoff valves may be provided in each of the branched pipelines.

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

The backlash type actuator for a valve shown in FIG. 1 according to the present invention includes a pair of double-acting hydraulic cylinders 2a and 2b disposed opposite to the actuator body 1, and their respective cylinder chambers X t , X 2 , Y It consists of a pair of gas oil tanks 9a and gb for supplying pressure oil to the piston rods 20 and 20, and its output is transmitted via a swinging member 21i that engages with the piston rod 20 and a key (not shown). The signal is transmitted to the stem 15a of the valve 15. The valve 15 disposed in the pipeline 30 has a conduit 22a that transmits gas on its primary side and secondary side to the shuttle valve 4 via the stop valve 3.
.
It is connected to a pressure gauge 16' via a pressure gauge 16'. Solenoid valve 5a,
The pipe lines 24, 25 branched off at 5b are connected to the tops of the gas oil tanks 8a, 8b, respectively. Each tank Ba,
Filters ga and gb are respectively installed in the bottom of gb, and the filter 9a.

The conduits from 9b are connected to the selector valve 12 via flow control valves 10a and 10b, respectively.

Reference numeral 14 designates a level check valve provided in a pipe connecting both tanks, and is opened to adjust the amount of oil in both tank systems.

The pipe line 26 from the tank 8a is connected to the screw rod side cylinder chamber X of the cylinder 2a by a branch pipe 26a, and is connected to the head side cylinder chamber Y2 of the cylinder 2b by a branch pipe 2'6b, and is connected to the cylinder chamber Y2 on the head side of the cylinder 2b by a branch pipe 2'6b. The pipe line 27 from is a branch pipe 27a.

27b opens the head side cylinder chamber Y of the cylinder 2a.
and piston rod side cylinder chamber x2 of cylinder 2b
are connected to each. The manual pump 11 is used to open and close the air conditioner/<J rev when there is no gas in the pipeline, and is connected to a selector valve 12.

In the actuator configured as described above, when opening the illustrated valve in the closed state, when the solenoid valve 6a is energized and turned on, I Among the gases to be used, the gas on the high pressure side is selected by the shuttle valve 4,
After being dehydrated in the iderator 5, it is introduced into the tank 8a via the pressure cutoff valve 13 and the electromagnetic valve 6a. This tank 8a
After the pressure oil pressurized by the gas introduced into the cylinder is filtered by a fill filter, it passes through the flow control valve 10a and the selector valve 12, and enters the cylinder chamber 5 of the hydraulic cylinder 2a and the cylinder Y2 of the cylinder 2b. , the piston rod 20 is operated to the left in the figure to drive the valve 15 and open it. On the other hand, the oil in the cylinder chamber Y of cylinder 2a' is the same as that of cylinder 2b. The oil from the tank chamber x2 passes through the selector valve 12, flow control valve 10b and filter 9b to the tank 8b! The gas in the tank is returned to pipe 2.
5 to the outside via the solenoid valve 6b and the pipe 29.

The solenoid valve 6b is in an off state.

During this opening operation, if the load on the valve 15 increases for some reason and exceeds the rating, the output of the actuator will increase accordingly (see line AB in Figure 2).
When the gas pressure in the pipe line 23 reaches a preset pressure,
The pressure cutoff valve 13, which is normally in the open position shown in the figure, is switched to the closed position, the pipe line 23 is cut off, and the supply of gas to the tank 8a is stopped. Therefore, even if the pressure in the pipeline increases further, the output of the actuator remains an appropriate output corresponding to the required driving force of the valve (second
Referring to line BC in the figure, overloading of the actuator can be prevented.

When closing the valve 15, contrary to the above case, when the solenoid valve 6b is energized and turned on, the oil in the tank 8b is pressurized by the gas in the pipeline, and the pressure oil causes the piston rond 20 to move. The valve is driven to the right in the figure, and reaches the state shown in FIG. 1, where the valve is closed. In this case as well, when the gas pressure in the pipeline exceeds a preset pressure, the pressure cutoff valve 13 is activated and cuts off the pipe line 2'3, so that the actuator is protected in the same way as in the previous case.

As is clear from the above description, the backlash extraction type actuator for valves according to the present invention is provided with a pressure cutoff valve in the pipeline that supplies gas to the gas oil tank, and the gas pressure in the pipeline is If this value is exceeded, the pipe line is shut off and the output of the actuator is suppressed to an appropriate value corresponding to the required valve torque that does not exceed the design allowable output, thereby preventing damage due to overload. In addition, there are no fatal problems such as incorrect cutting of a special key or incorrect opening of the valve due to incorrect cutting, and the reliability of the valve drive device is improved, making it safe to use, and using a general key. This eliminates the need to pay special attention to the quality control of key materials, allowing cost reductions.

In addition to this, there are other advantages such as ease of actuator design.

[Brief explanation of drawings]

FIG. 1 is a system diagram of a backlash extraction type actuator for a valve according to the present invention, and FIG. 2 is a diagram showing its output characteristics. 2a, 2b - Hydraulic cylinder, 4... Shuttle valve,
5a, 5b...Solenoid valve, Ba, Bb...Gas oil tank, 13...Pressure cutoff/valve. Patent applicant: Kobe Steel, Ltd. Agent: Patent attorney: Aohaku Ao and 2 others

Claims (1)

[Claims] (1) Consisting of a pair of gas oil tanks and a double-acting cylinder, the oil in one tank is pressurized by the gas pressure in the pipeline, and the cylinder is operated by the pressure oil and installed in the pipeline. In the gas/hydraulic actuator for the valve that drives the valve, a pipe line for introducing gas in the pipeline into the pair of gas oil tanks,
A gas/hydraulic actuator for a valve, comprising a pressure cutoff valve that shuts off the pipeline when the pressure in the pipeline exceeds a predetermined value.