JP3318521B2 - Fluid leak detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid leak detecting device, and is used, for example, for detecting a leak of cooling water at a tip of a spot welder.

[0002]

2. Description of the Related Art FIG. 7 is a diagram showing a conventional fluid circuit for detecting a fluid leak. In FIG. 7, the cooling water flow path RT
A series connection of a stop valve VL1, a flow detector DQj1, and a gun GN1 is connected between the primary side RT1 and the secondary side RT2. Similarly, the series connection of the on-off valve VL2, the flow rate detector DQj2, and the gun GN2 is connected to the other gun GN2. As described above, the cooling water circuits of the many guns GN1, GN2,... Are connected between the primary side RT1 and the secondary side RT2.

[0003] From the flow rate detectors DQj1 and DQj2, a detection signal corresponding to the flow rate of the cooling water is output, and it is monitored whether the flow rate has dropped below a set value. For example, when the detection output of the flow rate detector DQj1 falls below the set value,
It is assumed that a cooling water leak has occurred in the gun GN1.
Close the stop valve VL1.

[0004]

However, in the conventional detection circuit, even if the gun GN1 does not leak, the output flow of the pump P fluctuates or the other gun GN2 leaks or is not used. Because of this, the flow rate flowing through the flow rate detector DQj1 fluctuates greatly, so it is necessary to set a low set value for issuing an alarm output, that is, to set a large fluctuation range of the flow rate as a condition for issuing an alarm output. .

[0005] For this reason, when a small leak has occurred in the gun GN1, it has not been possible to accurately detect it. The present invention has been made in view of the above-described problems, and has as its object to provide a fluid leakage detection device that can accurately detect fluid leakage such as leakage of cooling water from a gun tip. .

[0006]

[0007]

According to a first aspect of the present invention, there is provided an apparatus in which a rotor having a straight internal flow path and having blades is provided.
Two flow rate detectors for rotating the fluid and outputting a detection signal according to the flow rate, and a flow path of the two flow rate detectors
In a state where they are arranged side by side so as to be parallel to each other
Ports that connect linearly at both ends of the internal flow path
And two connecting blocks that are integrally connected to each other across the surfaces at both ends of the flow path.

According to a second aspect of the present invention, there is provided a comparison circuit for comparing two detection signals output from the two flow detectors, and a difference between the two detection signals output from the two flow detectors. An output circuit for outputting an alarm signal when the value exceeds a preset value is provided integrally.

[0009]

FIG. 1 is a diagram showing a cooling water circuit CC using a fluid leak detecting device DQ according to the present invention, FIG. 2 is a front view of a flow detecting unit 11 of the fluid leak detecting device DQ, and FIG. FIG. 4 is a rear view of the flow detection unit 11 of the fluid leakage detection device DQ, and FIG. 5 illustrates the operation principle of the flow detection unit 11 of the fluid leakage detection device DQ. FIG. 6 is a circuit diagram of the detection circuit 21.

In the cooling water circuit CC shown in FIG. 1, between the primary side RT1 and the secondary side RT2 of the cooling water flow path RT,
The stop valve VL1, the fluid leak detection device DQ1, and the gun GN1 are connected. Similarly, for the other gun GN2, the on-off valve VL2 and the fluid leakage detection device D
Q2 and gun GN2 are connected. in this way,
Between the primary side RT1 and the secondary side RT2, many guns G
, And a fluid leak detection device D for supplying cooling water to each of N1, 2, 3,.
Are connected. Since the configuration of each of the fluid leak detection devices DQ1, 2, 3,... Is the same, only one of them, the fluid leak detection device DQ1, will be described.

The fluid leak detecting device DQ1 comprises a flow detecting unit 11 and a detecting circuit 21 not shown in FIG. 1 but shown in FIG. 2 to 4, the flow rate detection unit 11 includes two flow rate detectors 13 for outputting a pulse signal Sp having a frequency corresponding to the flow rate.
A, 13B, 2 attached by bolts 16, 16... For integrally connecting the flow rate detectors 13A, 13B.
It consists of two connecting blocks 14A, 14B, a block 15, and the like. Since the flow detectors 13A and 13B are substantially the same, only the flow detector 13A of the main structure will be described.

As shown in FIG. 5, the flow detector 13A has a rectangular parallelepiped main body 130 made of a metal material such as an aluminum alloy or a synthetic resin material, and rotates around a shaft 133 with respect to the main body 130. , A permanent magnet 132 attached to the tip of the blade of the rotor 131, and a sensor 134 provided on the main body 130 and responsive to the permanent magnet 132.

When the fluid flows through the flow path 135 provided in the main body 130, the blades move together with the fluid, and as a result, the rotor 131 rotates. When the rotor 131 rotates, the permanent magnet 132 moves with it, and accordingly, the pulse signal Sp is output from the sensor 134. In the example shown in FIG. 5, when the rotor 131 makes one rotation, the sensor 134 outputs three pulse signals Sp. This pulse signal Sp is the detection signal in the present invention. In addition, the flow rate detector 1 which operates on such a principle
3A itself is known.

As shown in FIG. 2, a cylindrical peripheral wall 130a is provided at the center of the main body 130.
A cylindrical recess is formed inside 30a. The rotor 131 is fitted into this recess, and is sealed with a transparent cover 136 screwed into the inner peripheral surface of the peripheral wall 130a. With the transparent cover 136, the state of rotation of the rotor 131 can be easily checked from the outside. Also, the main body 130
, A rectangular parallelepiped container-shaped cover 137 is attached on the back side. Inside the cover 137,
The detection circuit 21 is incorporated. The electric wire CV is drawn out from the connector CN attached to the cover 137, and is connected to the detection circuit 21 of the counterpart flow detectors 13A and 13B or to the outside.

The main body 130 of the flow detector 13A has a leak indicator light PL1 that emits yellow light and a reset button BT.
1 is provided. The main body 130 of the flow detector 13B is provided with a flow indicator PL2 that emits red light and a flow setting trimmer BT2.

The connecting blocks 14A and 14B have ports 141, 142 and ports 143, 14 respectively.
4 are provided. The ports 141 and 143 are connected to the flow path 135 of the flow detector 13A, and the ports 142 and 144 are connected to the flow path 135 of the flow detector 13B. Screw holes 145, 14 for attaching the whole to a frame or the like are provided on the back surfaces of the connecting blocks 14A, 14B.
5 and 146, 146 are provided.

As can be understood from FIG. 2, the two flow rate detectors 13A and 13B are arranged side by side.
From the direction perpendicular to the direction in which they are arranged, they are sandwiched and integrally connected by the connecting blocks 14A and 14B.

In FIG. 6, the detection circuit 21 includes F / V converters 211 and 212, zero point adjusters 211a and 212a,
It comprises a comparator 213, an absolute value converter 214, a comparator 215, a flow setting trimmer BT2, a latch circuit 216, an output circuit 217, and the like.

When the pulse signals Sp1 and Sp2 are input to the F / V converters 211 and 212, they are converted into voltages AV1 and AV2 proportional to the frequency of the pulse signals Sp1 and Sp2, respectively. The voltage AV1, when the pulse signal Sp is not input,
2 is adjusted by the zero point adjusters 211a and 212a. Therefore, by adjusting the zero point adjusters 211a and 212a, it is possible to provide an offset between the voltages AV1 and AV2, whereby the absolute value converter 214 and the comparator 215 at the subsequent stage can be omitted. It is.

The comparator 213 includes F / V converters 211 and 211
12 and outputs a voltage BV corresponding to the difference between the voltages AV1 and AV2. The voltage BV can take a positive or negative value. Absolute value converter 214 outputs the absolute value of voltage BV. The comparator 215 compares the output from the absolute value converter 214 with the voltage VS set by the flow rate setting trimmer BT2, and when the output from the absolute value converter 214 exceeds the voltage VS, sets the output to “1”. ". Latch circuit 216
Outputs the output from the comparator 215 to the reset button BT1
Hold until a reset is performed. Output circuit 21
7 amplifies the output from the latch circuit 216 and outputs the amplified output to the outside as, for example, an on / off contact signal.

Next, the operation of the fluid leak detecting device DQ1 will be described. In FIG. 1, the stop valve VL1 is open, and cooling water is supplied to the gun GN1 via the fluid leak detection device DQ1. At this time, if there is no leakage of cooling water, the same amount of cooling water flows through the two flow rate detectors 13A and 13B, so that the frequency of the pulse signal Sp output from each of them is the same. Therefore, in the detection circuit 21, the voltage BV output from the comparator 213 is zero or small, and there is no output from the comparator 215.

Therefore, if the cooling water leaks due to the chip of the gun GN1 coming off, the amount of the cooling water flowing to the flow detector 13B becomes smaller than that of the flow detector 13A. Then, the frequencies of the pulse signals Sp are different from each other, and the voltage BV output from the comparator 213 increases.
When the voltage BV exceeds the voltage VS set by the flow rate setting trimmer BT2, an output for alarm is performed from the output circuit 217, and at the same time, the leak indicator light PL1 is turned on. By the output of the alarm from the output circuit 217, for example, the stop valve VL1 is closed, the leakage of the cooling water is stopped, and the influence on the other gun GN2 is blocked.

As described above, according to the fluid leak detecting device DQ1, by setting the setting of the detecting circuit 21 to an appropriate value, a slight leak of fluid such as a leak of cooling water of the tip of the gun GN1 can be accurately detected. Can be detected. The detection circuit 21 is built in the fluid leakage detection device DQ1, and the set value can be easily adjusted from the outside, so that adjustment and handling are easy. Since the ports 141 to 144 provided in the connection blocks 14A and 14B are close to each other, piping is easy.

In addition, since the fluid leak detector DQ1 is constructed by integrating the two flow detectors 13A and 13B, parts can be shared between the flow detectors 13A and 13B, and mass production is possible. Quality can be improved and the price can be reduced. In addition, each flow detector 13A, 1
Since the flow path 135 of 3B and the ports 141 to 144 of the connection blocks 14A and 14B are directly connected in a straight line, the cooling water is easy to flow and there are few failures.

According to the detection circuit 21 of the above embodiment,
Since the absolute value converter 214 and the comparator 215 are provided, even if any input of the F / V converters 211 and 212 is connected to any of the outputs of the flow detectors 13A and 13B, normal operation is performed. However, various circuits can be employed as the detection circuit 21. For example, as described above, in the F / V converters 211 and 212, one of the F / V converters 212 and 212a is controlled by the zero point adjusters 211a and 212a.
Is given so that the output voltage AV2 becomes larger by the set value, and the comparator 213 compares the voltage AV2 by subtracting the voltage AV1. Then, the configuration is such that an alarm is output when the output of the comparator 213 becomes negative. The flow detectors 13A, 13B
It is also possible to measure the flow rate of the cooling water itself using.

In the cooling water circuit CC, a flow rate detector DQm1 is provided on the primary side RT1 so that the entire flow rate can be measured. By comparing the total flow rate with the flow rate in each fluid leak detection device DQ, the operation state of the detection circuit 21 may be changed so that the most sensitive and accurate detection can be performed.

In the above embodiment, the permanent magnet 132
Various combinations of the sensor and the sensor 134 are possible. For example, an iron piece and a proximity sensor may be used. Further, the rotation of the rotor 131 or the shaft 133 may be optically detected.

The fluid leak detecting device DQ has not only a function of detecting a fluid leak but also a state in which the flow rate passing through the fluid leak detecting device DQ becomes a predetermined value or less and cooling cannot be sufficiently performed. In this case, a function of outputting a flow rate shortage alarm can be integrated. Thereby, the management of the cooling water is performed more effectively. Further, a flow rate display for displaying the flow rate flowing from the primary side into the fluid leak detection device DQ can be provided integrally with the fluid leak detection device DQ1. As such a flow rate display, for example, a panel that displays a flow rate as a digital value, a meter that displays an analog value, or the like can be used.

In addition, the configuration, shape, material, number, operation, etc. of the whole or each part of the fluid leak detection devices DQ1, DQ2 and the flow rate detectors 13A, 13B can be variously changed in accordance with the gist of the present invention. .

The fluid leak detecting device according to the present invention comprises:
It can be used for managing the flow rate of cooling water, pure water, or chiller discharge in semiconductor production, managing the cooling water of a molding machine, and managing various other flow rates.

[0031]

According to the present invention, leakage of fluid such as leakage of cooling water from a gun tip can be accurately detected.

Furthermore , each flow rate detection in which the internal flow path is straight
The flow path of the vessel and the connecting block are directly connected in a straight line.
Therefore, the cooling water flows easily and there are few failures .

[Brief description of the drawings]

FIG. 1 is a diagram showing a cooling water circuit using a fluid leak detection device according to the present invention.

FIG. 2 is a front view of a flow detection unit of the fluid leakage detection device.

FIG. 3 is a side view of a flow detection unit of the fluid leakage detection device.

FIG. 4 is a rear view of a flow detection unit of the fluid leakage detection device.

FIG. 5 is a diagram for explaining the operation principle of the flow rate detection unit.

FIG. 6 is a circuit diagram of a detection circuit.

FIG. 7 is a diagram showing a conventional fluid circuit for detecting fluid leakage.

[Explanation of symbols]

 11 Flow rate detection unit 13A, 13B Flow rate detector 14A, 14B Connecting block 213 Comparator (comparison circuit) 215 Comparator (comparison circuit, output circuit) 216 Latch circuit (output circuit) 217 Output circuit DQ Fluid leak detection device Sp pulse signal (Detection signal)

Continuation of the front page (56) References JP-A-4-309833 (JP, A) JP-A-63-36129 (JP, A) JP-A-9-292303 (JP, A) (58) Fields studied (Int .Cl. ⁷ , DB name) G01M 3/28

Claims (2)

(57) [Claims] An apparatus for detecting leakage of a fluid in a flow path , wherein the internal flow path is straight, and a rotor having blades is connected to the fluid.
Two flow detectors for rotating and outputting a detection signal according to the flow rate, so that the flow paths of the two flow rate detectors are parallel to each other
Linear at both ends of their internal flow path in side-by-side arrangement
A fluid leak detection device, comprising: two connection blocks that have ports that connect to the internal flow path, and that are integrally connected to each other while sandwiching surfaces at both ends of the internal flow path . 2. A comparison circuit for comparing two detection signals output from the two flow rate detectors, and a difference between the two detection signals output from the two flow rate detectors is set to a preset value. output circuit for outputting an alarm signal when exceeding becomes provided to be integrated, fluid leakage detecting apparatus according to claim 1.