JPS62198727A - Detecting method for leak of hydraulic pressure - Google Patents

Abstract

PURPOSE:To detect a leak in a valve, etc., of a hydraulic operation mechanism efficiently in safety by substituting a leak in the hydraulic system for the valve with a sensitive gas leak and using low-pressure gas, and detecting the amount of leak gas per unit time electrically. CONSTITUTION:An air bubble discharged from the tip 10a of a tube 10 in collected liquid 11 rises. The air capacity of each air bubble is considerably accurately constant on condition that the liquid level is constant, and when the air bubble leaves the tip 10a of the tube 10, an extremely small, impulsive sound is generated. Further, the frequency component of this pulse depends much upon the natural vibration frequency of the container 13 and the height of the air column up to the liquid surface and this is separated by a filter and integrated and displayed, so that a pulse train is obtained. Then, the amount of leak gas is detected electrically from the number of pulses of the pulse train.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a method for detecting hydraulic leakage, and in particular to valves and valves often used in the operation mechanism of power circuit breakers driven by hydraulic pressure. Related to improvements in leak detection of types.

(Conventional technology) Power circuit breakers are used not only to interrupt load current.

It also serves as an emergency device for the power system, and non-operation or abnormal operation is absolutely not allowed in response to operation commands.

Therefore, in addition to the original function of high speed and high output, the operating mechanism of the circuit breaker is equipped with various functions such as a function to prevent simultaneous excitation of the pilot valve and a function to prevent pumping, although I will not go into details individually, to ensure its operation. ing.

Hydraulically operated power circuit breakers are designed to detect a ground fault or similar accident in a power system, and upon receiving the command, shut the circuit off at extremely high speed in order to prevent the accident from escalating. The energy behind this series of operations is the hydraulic pressure stored in the accumulator.

A piston for opening and closing contacts is driven by opening and closing various valves in a preset order.

So, if the sealing function of the valve is bad,
Since the pressure cannot be maintained, the series of operations may not be completed or may be insufficient, and the circuit breaker will not be able to perform its original function. Therefore, it goes without saying that valve sealing performance is one of the most basic functions of a hydraulic operating mechanism.

Conventionally, the sealing performance of valves has been checked in a very strict manner by applying pressure higher than the specified pressure for a long period of time prior to actual assembly.

(Problem to be solved by the invention) However, the operating pressure of the hydraulic operating mechanism is high, several hundred atmospheres, and if leakage gradually occurs under this condition, it is necessary to leave it for a long time. Improvements were desired from both safety and testing efficiency points of view.

The present invention has been made in consideration of the above points, and its purpose is to provide a hydraulic leakage detection method that safely and efficiently detects leakage of valves of a hydraulic operating mechanism. .

[Structure of the invention]

(Means for solving the problem) Low-pressure gas is introduced from one opening of the valve, and the leaked gas is passed through the other opening through the part of the valve where the valve body is closed, and then sent to the collection liquid through a tube. Introduce it inside.

The present invention is characterized in that leakage of valves of the hydraulic operating mechanism is efficiently detected by measuring the pulse rate of bubbles of leaking gas released from the tube and detecting the amount of leaking gas.

(Embodiment) An embodiment of the hydraulic leakage detection method of the present invention will be described below with reference to FIGS. 1 to 5. In FIG. 1, a valve 1 is one opening formed in a valve seat 2 by a valve body 1a housed within the valve seat 2.

That is, the first opening 2a is closed, and the other opening, that is, the second opening 2b, which communicates the space inside the valve seat 2 in which the valve body 1a is accommodated with the outside of the valve seat 2 is formed.

One end of the valve body 1a is pressed by the other end of a compression spring 3 fixed to a fixed part 4 corresponding to a part of a hydraulic operation mechanism (not shown) so as to close the first opening 2a. A compression spring 3 is provided.

The configuration of one embodiment of the present invention is such that, for example, a dry air cylinder 5 is connected to a pipe 7 via a regulator 6.
is provided with a pressure gauge 7a. The pipe 7 is also connected to the first opening 2a of the valve 1 via a tube valve 8. Also, a tube 10 connected to the second opening 2b of the valve 1
into the collection liquid 11 filled in the container 12. The tip 10a of this tube 10 is guided into the gas collection container 13, and gas in the collection liquid 11 can be collected. A detector 15 for detecting bubble sound, such as a vibration acceleration pickup, is attached to the outside of the upper lid 13a of the gas collection container 13. This detector 15 is led to a measurement display device (not shown) by a signal line 1G.

In addition, as shown in FIG.
A detector 15 mounted on the outside of 3a is connected to a measurement display 23 by a signal line 16. This measurement display device 23 includes an amplifier 17. Filter 18. A display 19 is housed and is adapted to measure the pulse sound of the bubbles 14.

As shown in FIG. 3, the output data 20 of the display 19 of the measurement display device 23 displays the pulse sound of bubbles as shown in pulse note @21.

Next, a method according to an embodiment of the present invention will be described.

When a predetermined low pressure is applied to the first opening 2a of the valve 1 from, for example, a dry air cylinder 5 instead of oil pressure, air flows into the valve seat 2 from the first opening 2a blocked by the valve body 1a. This air leaks from the second opening 2b as indicated by the arrow 9.
The gas passes through the tube 10 as shown in FIG. By recording such pulse sounds of the bubbles 14, it is possible to replace gas leakage with oil leakage and detect the presence or absence of oil leakage, as will be described later.

Detection of such gas leakage will be explained again. The bubbles 14 released from the tip 10a of the tube 10 in the collection liquid 11 are released from the tube 10 and rise with a size that balances buoyancy and surface tension. The air volume per bubble is fairly accurately constant if the water surface height is constant.

Also, when examining the minute sound when bubbles are generated, tube 1
It has been found that when the bubble leaves the tip 10a of the 0, a pulse-like sound is emitted. In addition, since the frequency components of this pulse have large components related to the natural frequency of the gas collection container 13 and the height of the air column to the water surface, these are filtered by the filter 1.
When separated by 8 and integrally displayed, a pulse train like the pulse record 21 shown in FIG.

Furthermore, we will discuss equidominance that uses gas pressure instead of detecting hydraulic leakage. In Figure 3, the vertical axis shows the amount of gas leakage (cc/
5ee), the horizontal axis shows the gas pressure, and an example is shown in which the gas leakage amount of two certain valves A and B was tested by changing the gas pressure using the method of the present invention.

At this time, the gas pressure is about 1 to 4 kglal, and the detected gas leakage amount is about 0.1 to several cc/sec. Also, when these valves A and B were tested using the conventional hydraulic leakage detection method, valve A did not leak at the specified hydraulic pressure, while valve B did not leak several cc.
/see was leaking.

A number of similar experiments have been conducted, and when summarized based on theoretical support, the relationship between a valve that leaks oil at a specified hydraulic pressure and a valve that is well closed is approximately as shown in FIG. 5.

In Figure 5, the vertical axis represents the amount of gas leakage (cc/5ec), and the horizontal axis represents the gas pressure.The straight line shown in Figure 5 shows whether oil leaks at the specified oil pressure or not. It was found that the area is divided by a boundary line m like this. Therefore, it has been found that it is possible to fix the gas pressure at the gas pressure P11 and determine the presence or absence of oil leakage at the specified oil pressure based on the gas leakage amount Qs at this time.

In other words, it was found that on the vertical axis side across the boundary line m, there was oil leakage at the specified hydraulic pressure, and on the horizontal axis side, there was no oil leakage at the specified hydraulic pressure. The reason why gas leaks are more sensitive than oil leaks is because the molecular sizes of gas and liquid are extremely different.

In this way, it is possible to provide a hydraulic leakage detection method that detects the degree of valve occlusion in a shorter time and more quickly than conventional hydraulic pressure by using gas, that is, gas pressure, instead of hydraulic pressure.

Next, another embodiment of the present invention will be described with reference to FIG.

The same parts as in FIG. 1 are given the same reference numerals.

In the above-mentioned FIG. 1, an example of one system was explained, but as shown in FIG. 6, leakage can be detected from a large number of valves 1 at the same time by installing the valves in a number of systems, four systems as shown in the figure.

To explain further, after setting a predetermined gas pressure from the first opening side (not shown) of the valve 1, the solenoid valve 25 is opened for a certain period of time by the timer 26 to apply gas pressure to the first opening side. At this time, the amount of gas leakage 27a collected in the gas collection container 13 through the tube 10 connected to the second opening side of the valve 1 (not shown) is determined by the set scale 27, that is, the timer 26 Gas leakage amount 27a that leaked within the predetermined time set by
Depending on whether the amount of gas leakage 27a of the valve 1 reaches or exceeds the scale 27, it can be determined to be defective, and if it does not reach the scale 24, it can be determined to be good.

〔Effect of the invention〕

As explained above, according to the present invention, a leak in the hydraulic system of a valve is replaced with a sensitive gas leak, low-pressure gas is used, and the amount of leak gas per unit time is detected electrically. Accordingly, it is possible to provide a hydraulic leakage detection method that can safely and efficiently detect leakage from a valve of a hydraulic operating mechanism. Furthermore, since oil is not used for detection, there is an advantage that processing such as cleaning of the inspected valve after inspection is not necessary.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the present invention, FIG. 2 is a circuit diagram of a signal detection and display device of the present invention, FIG. 3 is a diagram of pulse detection data in FIG. 2, and FIG. 4 is a diagram of a valve. FIG. 5 is a diagram showing the results of leakage measurement based on gas pressure, FIG. 5 is a diagram showing the experimental results of the relationship between gas leakage and oil leakage, and FIG. 6 is a perspective view showing another embodiment of the present invention. 10...Tube 11...Collection liquid 12.
... Container 13... Gas collection container 14...
・Air bubbles 15...Detector 16...Signal line 23...Measurement display device 25...Solenoid valve
2t...Timer 27...Set scale
27a...Gas leakage force Figure 4

Claims (2)

[Claims] (1) In a method for detecting hydraulic leakage from valves in a hydraulic operating mechanism, low-pressure gas is introduced from one opening of the valve, and leaked gas is detected from the other opening via the closed part of the valve body of the valve. The amount of leaked gas is detected by introducing the gas into the collection liquid through a tube, placing the tip of this tube into a gas collection container, and measuring the pulse sound of leaked gas bubbles coming out from the tip of the tube. A hydraulic leakage detection method characterized by: (2) The quality of the valve is determined based on whether the number of pulses of bubbles released from the tube into the gas collection container or the amount of leaked gas containing bubbles reaches a set value. Hydraulic leak detection method.