JPH02216427A - Leakage detecting device - Google Patents

Abstract

PURPOSE:To detect a leakage and to specify a leakage part by installing leakage detecting parts whose resistance values are different from each other in plural side grooves, and also, allowing an electric current to flow to a detecting circuit to which these detecting parts are connected in series. CONSTITUTION:On bottom parts of side grooves 3a - 3c, leakage detecting parts consisting of resistors 10a - 10c, and electrodes 11a, 12a - 11c, 12c provided on both sides by placing this resistor between them are provided. These leakage detecting parts are connected in series and form a detecting circuit. In this state, when an inductive leakage liquid 1 flows down into the side groove 3a, the electrodes 11a, 12a for inserting and holding the resistor 10a are short- circuited. Therefore, a resistance value of the resistor decreases, and a resistance value of the detecting circuit is varied. As a result, a varied circuit current is detected by a leakage monitoring device 14, and by comparing it with a set value which is set in advance, the generation of a leakage and its generated place are specified, and it is brought to alarm display and informed to an operator.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a device for detecting leakage from piping, equipment, tanks containing conductive liquid in various plants, etc.

(Prior Art) In various plants such as power plants and chemical plants, many devices such as piping and tanks containing conductive liquid are installed. These piping systems have many connections where piping and piping or piping and equipment are connected using flanges.
Regarding this connection, there is a possibility that the contained liquid may leak due to loosening of the tightening bolt or deterioration of the packing. In addition, a level meter is installed in the tank to monitor and control the level of the liquid in the tank, and when the liquid reaches a certain level,
Prevent the liquid in the tank from overflowing by starting the pump that discharges the liquid in the tank, stopping the pump that supplies the liquid, or issuing an alarm to prompt the operator to take the specified action. There is.

However, if a failure occurs in these measuring devices, there is a possibility that the liquid in the tank will overflow. Unexpected leakage or overflow of liquid from various devices causes various inconveniences for plant operators, so conventional measures such as bulkheads and other facility measures have been taken to detect leaks and prevent leaks from spreading. Countermeasures are being taken through inspection and maintenance of equipment. On the other hand, in the event of a leak, a leak detection device was installed that would allow measures to be taken at the initial stage of the leak, such as closing the isolation valve or stopping the pump, to prevent the amount of leak from increasing any further.

Figures 4 and 5 are an installation sectional view and a circuit configuration diagram of a conventional leakage detection device. When the electrode rod 4a of No. 4 becomes conductive, this detection signal is transmitted via the cable 5 to an amplifier device 6 consisting of a relay gas power source 6b installed in a control room where an operator (not shown) resides, and the display 7 indicates that the operator was issuing a warning.

(Problem to be Solved by the Invention) In the conventional leakage detection device, when detecting leakage from a plurality of floors 2, an electrode level switch 4, a cable 5 and It is necessary to install one set of amplifier devices 6 at a time, and therefore, in order to deal with a large number of gutters 3 in a large plant, it is necessary to install as many devices as there are detection locations, and to install them as well as a central control station where operators are permanently stationed. A long round trip cable 5 must be laid to reach the room.
There was a problem that the construction work would be extremely large-scale.

In addition, in this leakage detection device, if there is no leakage, no current is flowing through the cable 5, so a circuit breakage failure in the cable 5, etc. is determined each time by using the electrode level switch 4 installed in the gutter 3. It is necessary to short-circuit the electrodes 4a and emit a simulated signal for inspection and investigation, and thus there is a problem in that it takes a lot of work time to perform maintenance such as checking the integrity.

The present invention has been made in view of the above, and its purpose is to install leak detection parts with different resistance values in a plurality of side gutters, and to flow current through a detection circuit in which these parts are connected in series. It is an object of the present invention to provide a leak detection device having a simple configuration and easy maintenance, which detects leaks, identifies leak locations, and constantly detects abnormalities in a detection circuit.

[Structure of the Invention] (Means for Solving the Problems) A leakage detection section is installed in a plurality of side gutters and consists of electrodes sandwiching resistors having different resistance values, and these leakage detection sections are connected to each other using a cable or the like. A leak monitoring device that includes a detection circuit connected in series, applies voltage to this circuit, detects changes in current, and compares it with a preset value to detect leaks, identify the location where the leak has occurred, and notify of abnormalities in the detection circuit. Equipped with.

(Function) When conductive leaked liquid flows down into the side gutter due to leakage of contained liquid from piping, etc., the electrodes that sandwich the resistor of the leak detection section installed at the bottom of the side gutter are short-circuited.

As a result, the resistance value of the resistor decreases, and the resistance value of the detection circuit changes. The circuit current that has changed as a result is detected by a leakage monitoring device, and compared with a preset value to detect the occurrence of leakage and identify the location where the leakage occurred, and display an alarm to inform the operator of this. Also, since the current in the detection circuit is constantly measured regardless of whether there is leakage or not, abnormalities such as disconnections in the detection circuit including cables can be detected.

(Example) An embodiment of the present invention will be described with reference to the drawings.

Note that the same components as those in the prior art described above are given the same reference numerals, and detailed explanations will be omitted.

FIG. 2 is a sectional view explaining the installation and shows an example of three leakage detection parts. Gutters 3a are installed at the lowest positions of floors 2a, 2b, and 2c.

3b and 3c are provided, and resistors 10a and 3c are provided at the bottom of the resistors 10a and 3c, respectively.
10b.

lOc and electrodes 11a, 12a and llb, 12b and lie made of bare electric wires connected on both sides with this in between.
, 12c as insulators 13a, 13b, 13c
A leak detection unit configured by being attached to the Each of these resistors 10a, 10b.

LOc and electrodes 11a, 12a and llb, 12b
and Ilc.

12c are sequentially connected in series by an insulated cable 15 from a leak monitoring device 14 installed in a control room where an operator is permanently stationed, thereby forming a detection circuit. Note that this cable 15 passes through a conduit 16 buried under the floor.

Further, the insulator 13 is provided in the side grooves 3a and 3b.

3c and the conduit 16, for example, the electrode 11
a, 12a and flb, 12b and llc,
12e as a hermetic seal, side grooves 3a, 3b
, 3c is provided with a seal. Furthermore, the leak detection section is designed to prevent foreign matter such as dust from falling, and to prevent the leakage liquid from falling.
The surrounding area is surrounded by a water column filter 17 made of asbestos or the like so as not to impede the intrusion of water, and this filter 17 is sandwiched between supporting wire meshes 18 and attached with mounting brackets 19 to side gutters 8a, 8b,
? It is fixed to lc. Note that the resistors 10a and 10b
, lOc may be buried in each insulator 18 in a different configuration from the illustrated example as a measure to prevent contamination.

As shown in the circuit diagram of FIG. 1, the leakage monitoring device 14 is composed of a power source 14a, a current limiting resistor 14b, a leakage determination section 14c, a display signal conversion section L4d, an alarm 14e, and a display 14f. The power source 14a has each resistor 10a connected in series by the couple 15 via the leakage determination section 14c and the current limiting resistor 14b.
, 10b, foe and electrode ILa, 12a%
flb.

A voltage is applied to a detection circuit consisting of 12b%llc and 12c, and a current is constantly caused to flow. In addition to measuring this current in the leakage determination section 14c, the current value when a leak occurs is stored in advance and compared with the current at the time of leakage, and a determination signal indicating the presence or absence of leakage is issued to the alarm 14e to detect the leakage. Give a warning. Furthermore, a current signal is output to the display signal converter 14d. In the display signal converter 14d, in normal state, abnormality such as circuit breakage, and the gutter 3a, 3b, 3
The current values are set in advance for each case of leakage and for various combinations of these, and the circuit current value is converted into a signal indicating normality, circuit breakage, and leakage location, and the signal is transmitted to the display 14f. and notify the operator. Note that it is easily conceivable that the display signal converting section 14d and the leakage determining section 14c be constructed of an electronic computer or the like.

Moreover, each of the above-mentioned resistors 10a, fob, lOc
The resistance value R is determined by combining various combinations so that the circuit resistance values at that time are not confused and the shorted position can be clearly identified.For example, the following (1), (2), (3) A value that satisfies the formula.

R10a +RIOb≠R10c...--(1)
R10a +RIOc +R10b (2)
R10b + R10c * R10a --(3) Here, R10a, Rfob, and R10c are each resistor 1
0a.

10b and 10c. (However, the current limiting resistor 14b is not taken into consideration.) Further, an explanatory diagram for resistance value selection that clarifies this relationship is shown in FIG.

In addition, in the following example, the above (1) and (2)
.

The resistors 10a, 10b, 1 according to equation (3)
It is assumed that the resistance values of 0c are 400Ω, 200Ω, and 100Ω, respectively, the resistance value of the current limiting resistor 1b of the leakage monitoring device 14 is 100Ω, and the voltage E of the current g14a is 10V DC.

At this time, the explanation will be made while ignoring the resistances of other cables 15 and the like.

Next, the effect of the above configuration will be explained. First, if there is no leakage on any of the floors 2a, 2b, and 2c,
The leakage determination unit 14c of the leakage monitoring device 14 includes electrodes Ha and 12a in the side gutters 3a, 3b, and 3c.

Resistor 1 between 11b and 12m and lie and 12c, respectively
0a.

10b, lOc resistance value 400Ω+200Ω+10
The resistance value of 0Ω-700Ω is passed through the cable 15, and the resistance value of 100Ω of the current limiting resistor 14b is added, so that the detection circuit resistance at this time becomes 800Ω. Here, the voltage E of the power supply 14a is DC tOV, 10 (V) / 800 (
Q) A current of -0,0125 (A) flows. This corresponds to the current value E/8R in FIG.

Next, when a disconnection occurs in the detection circuit, such as the cable 15, the resistance of the circuit becomes infinite and the current becomes zero.

This corresponds to the cable disconnection shown in Figure 3.

When a leak occurs and the leaked liquid 1 flows into the side gutter 3a, the electrode 1
1a and 12a are electrically short-circuited by the leaked liquid 1, and the resistance value of 400Ω of the resistor 10a becomes 0, so the detection circuit resistance is 800-400-400Ω, and the current flowing at this time is 10/400-0.025 (A) becomes. This corresponds to the current value E/4R in FIG.

Furthermore, if the leaked liquid 1 flows into the side gutter 30 and leakage is detected at two locations, the side gutter 3a and the side gutter 30, the resistor 10
Resistance value of a and resistor 10c: 400+ 100-500Ω
is 0, so the detection circuit resistance is 8QO-500■30
At 0Ω, at this time 10/300-0.033(A)
current flows. This corresponds to E/3R in FIG.

If the leaked liquid 1 flows into all the gutters 3a, 8b, and 3c, the resistance values 400+200+100-700Ω of the resistors lea, lOb, and foe become 0, but the detection circuit resistance increases due to the resistance value 100Ω of the current limiting resistor 1b. is 800-700 and 100Ω, and the current at this time is l O/
It becomes 100-0.1 (A). Note that this is E in Figure 3.
/IR, and in this way, gutters 3a, 3b,
3a All resistors 1. Oa.

Even if the resistance value of 10b and 10c becomes O, the resistance value of 100Ω of current limiting resistor ib remains, so the power supply 14
A will not be damaged due to short circuit.

As described above, when any of the leakage detection parts, even if there are multiple ones, is short-circuited by the leakage liquid 1, the detection circuit current that changes due to this is detected by the leakage determination part 14c of the leakage monitoring device 14 to detect the occurrence of leakage. The leakage location is identified by comparison with a preset current value in the alarm device 14 and the display signal converter 14d, and is displayed on the display device 14f' to notify the operator. Furthermore, since a small current is always flowing through this detection circuit, it is constantly monitored for circuit breakage and abnormality detection, so as soon as an abnormality occurs, it can be notified immediately. Therefore, during maintenance and inspection, each leakage detection part must be cleaned and inspected. Only the continuity of the electrodes is checked, and the cable length is short, so there is little chance of failure.

[Effects of the Invention] According to the present invention, a leak detection section consisting of one resistor and a pair of electrodes on both sides is provided at a location where detection is required, and a cable is connected to connect the leak detection sections at multiple locations to each other. Since the configuration is simple, just connect them in series, only a small amount of cables are required and the installation work is simple. Furthermore, abnormalities such as disconnections in detection circuits including cables can be detected and alarmed in the same way as leakage detection, which improves reliability and simplifies installation and maintenance work, which also burdens workers and operators. It has the effect of reducing

[Brief explanation of the drawing]

Fig. 1 is a circuit configuration diagram of the present invention, Fig. 2 is a sectional view explaining the installation, Fig. 3 is an illustration explaining resistance value selection, Fig. 4 is an installation sectional view of a conventional leakage detection device, and Fig. 5 is the circuit configuration. It is a diagram. 1...Leaked liquid, 2a, 2b, 2cm floor, 3a, 8b, 3C--Gutter, 10a, 10b, lOc--Resistor, 11
a, llb, lie, 12a, 12b
, 12c - electrode, 13... insulating material,
14... Leak monitoring device, 14a... Power supply, 1
4b...Current limiting resistor, 14c...Leakage determination section, 14d...Display signal conversion section, 14...Display device 14f1 148...Alarm device, 15...Cable. Agent Patent Attorney Norio Ogo

Claims (1)

[Claims] A leakage detection section consists of a plurality of resistors with different resistance values and electrodes at both ends sandwiching the resistors, and one or more leakage detection sections are connected in series with a cable etc. to form a detection circuit, and a voltage is applied to this detection circuit. It is characterized by a leak monitoring device that detects current changes due to changes in the resistance of the detection circuit and compares them with preset values to detect leaks, pinpoint the location of leakage, and notify abnormalities in the detection circuit. leak detection device.