JPS61107128A - Method for detecting leakage of fluid - Google Patents

Abstract

PURPOSE:To detect the leakage of a fluid, by arranging a leaked fluid receiving part electrically insulated from piping parts around the conductor part of the piping parts and detecting the change in impedance by applying AC voltage between the conductor part of the piping parts and that of the receiving part. CONSTITUTION:A metal fitting 11, a joint 12 and piping 13, all of which comprise a conductor, are connected to the lower end of a hydraulic hose 10 and a leaked fluid receiving part 14 is arranged around the metal fitting 11. The receiving part 14 is constituted of an annular plate shaped electric insulating part 15 directly engaged with the periphery of the metal fitting 11 and a cylindrical conductor part 16 connected to the outer peripheral part of the insulating part 15 and a leaked fluid receiving space 17 is formed between the metal fitting 14 and the conductor part 16. An AC power source 18 can apply AC voltage to the metal fitting 11 and the conductor part 16 through a leaked fluid detection circuit 19. By this method, the conductivity or dielectric constant of the fluid accumulated between the metal fitting 11 and the conductor part 16 is detected and the generation of the leakage of the fluid can be detected by the change in impedance based on the detected value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting leakage of fluid leaking from piping components.

[Prior Art] As a means of ensuring the reliability of equipment, it is extremely important to detect abnormal conditions in equipment at an early stage and take countermeasures in terms of 3!2@ management. However, conventionally, detection of fluid leaks from piping parts such as rubber hoses, piping, pipes, valves, etc. has relied on visual inspection.

[Problems to be Solved by the Invention] However, the visual leak detection method described above particularly has the following problems:
It is almost powerless under difficult working conditions.

Additionally, a method of indirect leak detection by detecting a decrease in the liquid level in the fluid supply tank has also been adopted, but with this method, the location of the leak cannot be directly determined, and by the time the leak is noticed, it may already be detected. The disadvantage is that a considerable amount of leakage loss occurs.

Therefore, in conventional piping equipment, in order to prevent the occurrence of fluid leakage loss, piping, hoses, joints, etc. are regularly replaced, resulting in over-maintenance.

An object of the present invention is to detect fluid leakage accidents at an early stage and to enable early treatment of the leakage site.

[Means for solving the problem] The fluid leakage detection method according to the present invention includes disposing a leakage fluid receiving part electrically insulated from the piping part around the conductor part of the piping part. A leakage fluid receiving space is formed between the conductor part of the piping part and the conductor part of the leakage fluid receiving part, and a leakage fluid detection circuit is provided that applies an alternating voltage to both of the conductor parts to detect leakage from the piping part. Fluid leakage from piping components is detected by current changes in a leakage fluid detection circuit based on impedance changes between inner conductors due to fluid accumulated in a fluid receiving space.

[Function] According to the present invention, a leakage fluid receiving space is formed around a piping component, and a leakage fluid receiving space is detected by detecting a current change in a leakage fluid detection circuit at a remote location away from the piping component. It becomes possible to immediately detect the infiltration and accumulation of fluid into the piping, and therefore the occurrence of leakage from the piping parts.

[Example] Figure 1 is a detection system diagram showing an example of the present invention: J52
The figure is a sectional view showing the main part of FIG. 1.

1O is a hydraulic hose, and the lower end side of the hydraulic hose 1O is provided with a hose fitting 11 made of metal, that is, a conductor. A joint 12 and piping 13 are connected.

A leakage fluid receiving section 14 is arranged around the hose fitting 11. The leakage fluid receiving part 14 includes an annular plate-shaped electrically insulating part 15 that is directly fitted around the hose fitting 11 and made of an electrically insulating material, and a cylindrical electrically insulating part 15 that is coupled to the outer periphery of the electrically insulating part 15. A leakage fluid receiving space 17 is formed between the conductor part 16 made of metal and the hose fitting 11.
is formed.

18 is an AC power supply, and the AC power supply 1B connects the hose fitting 11 and the leakage fluid receiving II via a leakage fluid detection circuit 19.
AC voltage can be applied to the conductor portion 16 of &14.

Here, the AC power supply 18 allows the voltage 1 frequency to be changed. The leakage fluid detection circuit 19 is equipped with an ammeter 20 that can detect changes in current in the circuit, and the detection results of the ammeter 20 can be displayed on a remote display 21.

Therefore, in a state where there is no fluid leakage from the hydraulic hose IO, if fluid starts to leak due to deterioration of the hydraulic hose IO, etc., where the current value flowing through the leakage fluid detection circuit 19 is IO, a part of the fluid leaks from the hydraulic hose IO. The leaked fluid is transmitted along the outer surface of the leaked fluid receiving portion 14 and accumulates in the leaked fluid receiving space 17 of the leaked fluid receiving portion 14 . In this state, the leakage fluid receiving space 17 becomes a load with electrical capacitance, which is based on the electrical conductivity or permittivity of the fluid accumulated between the hose fitting 11 and the conductor portion 16 of the leakage fluid receiving part 14. Leak fluid detection circuit 1 due to impedance change
The value of the current flowing through 9! Changes to The remote display 21 is
The amount of change in this current Δ■=1-10 is displayed, thereby making it possible to detect the occurrence of leakage of the fluid.

Note that the AC power supply 18 can facilitate the detection of changes in the current flowing through the leakage fluid detection circuit 19 by adjusting the voltage and frequency.

Further, the present invention is particularly suitable for application to hydraulic oil piping, lubrication oil piping, etc. When the present invention is used, for example, for leak detection in a hydraulic turbine oil piping system.

AC 1tlt18 t pressure tlOV, M wave ez it
560H2, when the gap between the indicator fitting 11 and the conductor part 16 of the leakage fluid receiving part 14 is set to about 5H, the current value flowing through the leakage fluid detection circuit 19 is several smA, which is safe.

The specific shape of the leaked fluid receiving portion 14 will be explained below.

An example of specific setting conditions for the AC power supply 18 will be explained. As shown in FIG. 3, if the diameter of the hose fitting 11 is d, the gap between the hose fitting 11 and the conductor part 16 of the leakage fluid receiving part 14 is X, and the height of the conductor part 16 is H, then the leakage fluid receiving space 17, the surface aS of the hose fitting 11 is πdH, and the capacitance of the leakage fluid receiving space 17 is as follows (1
), and when the inside of the leakage fluid receiving space 17 is occupied by oil, the following equation (2) becomes C. Just [F/m]
and the dielectric constant of oil is @= 1.8.

Therefore, the current value I flowing through the leakage fluid 19 is:

When the voltage of the AC power supply 18 is E and the frequency is ω,! !
E ω C here, d=20ms, H=10mm
, X=5mm, I=10m A, E=1
If 0V is applied, ω=500H2.

[Effects of the Invention] As described above, the fluid leak detection method according to the present invention includes arranging a leakage fluid receiving part electrically insulated from the piping part around the conductor part of the piping part. According to
A leakage fluid receiving space is formed between the conductor part of the piping part and the conductor part of the leakage fluid receiving part, and a leakage fluid detection circuit is provided to apply an alternating current voltage to the inner conductor part, and the leakage fluid reception space is formed between the conductor part of the piping part and the leakage fluid receiving part. Fluid leakage from piping components is detected by a current change in a leakage fluid detection circuit based on a change in impedance between the two passages due to fluid accumulated in the space. Therefore, it is possible to detect fluid leaks occurring in piping components at an early stage, and to take early measures to the site where the leaks occur.

[Brief explanation of drawings]

FIG. 1 is a detection system diagram showing an embodiment of the present invention. 2 is a sectional view showing the main part of FIG. 1, and FIG. 3 is a perspective view schematically showing the dimensions and shape of FIG. 2. lO...Hydraulic hose, 11...Hose metal fitting, 14.
...Leak fluid receiving part, 15...Electrical insulation part, 16...
- Conductor portion, 17... Leak fluid receiving space, 18... AC power supply, 19... Leak fluid detection circuit, 20... Ammeter.

Claims (1)

[Claims] (1) By arranging a leakage fluid receiving part that is electrically insulated from the piping part around the conductor part of the piping part, a gap between the conductor part of the piping part and the conductor part of the leakage fluid receiving part is provided. A leakage fluid receiving space is formed in the leakage fluid receiving space, and a leakage fluid detection circuit is provided to apply an alternating current voltage to both of the conductor portions. A fluid leak detection method that detects fluid leaks from piping parts by detecting current changes in the fluid detection circuit.