JPS59138934A - Leakage detector - Google Patents

Abstract

PURPOSE:To eliminate danger of an electric shock by using the detecting part of a leakage detector as a heat sensitive resistor element and insulating electrically the detecting part and a leaking body. CONSTITUTION:A series circuit of a resistor R1 and a heat sensitive resistor element Th1 and a series circuit of a resistor R2 and a heat sensitive resistor element Th2 are provided in parallel. Electricity is preliminarily conducted to the elements Th1, Th2 to increase beforehand the temp. of the elements. The element Th2 is provided in the position where a leaking body is easily detected, and the element Th1 is provided in the position where the element does not contact with the leaking body. The temp. of the element Th2 decreases by contact with the leaking body and the divided voltage of a voltage dividing point B changes. The voltages at the voltage dividing points A and B are compared with a voltage comparator C. When a difference arises in the voltages between the points A and B, a relay RY is operated by the output of the comparator C, by which leakage is detected. Since the leakage is detected by detecting the temp. of the leaking body, there is no danger for an electric shock.

Description

[Detailed description of the invention] [Temporary lj field] The present invention relates to a leak detector.

[Background technology] Conventional leak detectors install two electrodes on the floor where you want to detect the leakage object, such as water, oil, powder, granules, gas, etc., and use the harmonics of the leakage object to detect polarity. It was detected that the resistance value between the two was decreasing. In this method, even if a low voltage is applied between both electrodes, if there is poor insulation in the transformer on the receiver side, the receiver power supply voltage, e.g. ACloo V
or between the electrodes, posing a risk of electric shock.

[Purpose of the invention]

This invention was made to solve the above problems, and when a leakage body comes into contact with a heat-sensitive resistance element, ;i! ! It is an object of the present invention to provide a leakage detector which detects by lowering the temperature of the twin and which eliminates the risk of electric shock by electrically insulating a leakage body from a heat-sensitive resistance element which is a detection part.

[Disclosure of the invention]

The present invention will be explained below with reference to FIGS. 1 and 2, which are given as an embodiment. Leakage detector 1 has a resistor R in parallel to the power line t.
1 and the first heat-sensitive resistance element Th, and a series circuit of the resistor R and the second heat-sensitive resistance element Th are connected.

The resistors R, R, and the heat-sensitive resistance element Th1.7h are connected to the voltage comparator C from their respective divided voltage points A and B. The output line of the voltage comparator C is connected to the base of the transistor Tr via a resistor R6.
By switching rl, relay Ry is energized and the information is transferred.

The divided voltages a and b of the divided voltage points A and B are the divided voltage width a or the reference intraocular pressure of the voltage comparator C, and the other divided voltage is the voltage of the connected heat-sensitive resistor. When the element Th comes into contact with the leakage body, the temperature changes, and the resistance value changes. This changes the divided voltage, and the difference from the reference voltage causes the voltage comparator C to operate. The respective resistances R+”
i and heat-sensitive resistance element Th.

, Th, [column circuit is always energized, Joule heat,
That is, the temperature is raised by self-heating. This energization is caused by changes in the temperature, and if the temperature of the leakage object to be detected becomes close to the temperature of the leakage object, even if the leakage object or the heat-sensitive resistance element Th comes into contact, there will be no difference in resistance value and it will not be possible to obtain a detection output. Therefore, for example, the temperature should be raised to 40 to 56 degrees Celsius in advance, so that if the temperature is slightly lower than this temperature, it can be detected regardless of changes in temperature.

In addition, in order to prevent chattering of the -voltage comparator C, the characteristic values of the resistors R, , R2 and the heat-sensitive resistance elements Th, , Th, are not the same, but are somewhat higher than the divided voltage a and the divided voltage It is as it is.

FIG. 2 is a system diagram showing the connection state of this leak detector 1 and receiver 2, and shows the leak detector 1 including the internal circuit described above.
The two heat-sensitive resistance elements Th and Th, the element Th for detecting the leakage body, is installed at a position where it can easily be detected, and the element Th for the reference voltage is installed at a position where it does not come into contact with the leakage body. Power is supplied to the leak detector 1 from a receiver 2, and a detection output is output to the receiver 2. The power to the leakage detection section 1 may be supplied independently.

Next, the operation will be explained. Leakage body or heat sensitive resistance element Th.

When it comes into contact with the element Th, its temperature becomes low, and its resistance value increases. The output from the pressure comparator C switches the transistor Tr, energizes the relay Ry, and transmits the signal to the receiver 2 via the relay contact ry.

According to this embodiment, the heat-sensitive resistance elements Th1 and Th2 are either filled or exposed. Since there is no leakage, there is no leakage to the leakage body.

The present invention can be applied to liquids such as water and oil, as well as powders and gases, as long as they come in contact with the element Th and are exposed to heat.

〔Effect of the invention〕

As explained above, according to the leakage detector of the present invention, two heat-sensitive resistance elements are connected in parallel through respective resistors, and the heat-sensitive resistance elements of one of the heat-sensitive resistance elements of the leakage body are heated to a higher temperature than the leakage body by self-heating due to energization. The structure is characterized in that the leakage body is detected by contacting the element to lower the element temperature and detecting the change in resistance value accompanying this by a change in the divided voltage. In the method of detecting a change in resistance, there is a risk of electrical leakage to the fluid and an accompanying electric shock. However, in the present invention, a heat-sensitive resistance element is brought into thermal contact with the fluid, and the detection part Is there any need to expose 4 places? 4. There is no risk of electric shock (but there is also a risk of electrode corrosion and gas generation due to electrolysis due to contact between the wire electrode and leakage body), but it is extremely safe.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention, FIG. 1 is a circuit diagram, and FIG. 2 is a block diagram showing a T4 connection state of a leak detector and a receiver. 1... Leak detector, 7b,, 7h,... Heat sensitive resistance element, R,... Resistor. Patent applicant Matsushita Electric Works Co., Ltd. Representative patent attorney Toshimaru Takemoto (and 2 others)

Claims (1)

[Claims] 1) Two heat-sensitive resistance elements are connected in parallel through their respective resistors, and the self-heating caused by the heating causes the temperature to be higher than that of the leaking body.
A leakage detector characterized in that a leakage body is detected by contacting one of the heat-sensitive resistance elements of the leakage body to lower the temperature of the element and detecting a corresponding change in resistance value by a change in divided voltage. .