Leak detector of liquid in tank
First Claim
1. A leak detector of liquid in a tank, comprising:
- a measuring slim-tube into/from which the liquid in the tank is introduced or discharged through the lower end thereof;
a measuring tube connected to the upper end of the measuring slim-tube and having a sectional area larger than that thereof;
a sensor section additionally provided to the measuring slim-tube and including a first temperature sensor, a heater and a second temperature sensor arranged in this order along the measuring slim-tube, the sensor section measuring the flow rate of the liquid in the measuring slim-tube; and
a leak detection control unit connected to the sensor section,wherein the leak detection control unit has a pulse voltage generating circuit for applying a single pulse voltage to the heater and a leak detecting circuit connected to the first and second temperature sensors and generating an output corresponding to a difference between temperatures detected by the first and second temperature sensors, andwherein the leak detection control unit integrates a difference between an output of the leak detecting circuit and its initial value in response to the application of the single pulse voltage to the heater which is performed by the pulse voltage generating circuit to calculate a value equivalent to the flow rate of the liquid to thereby detect leakage of the liquid in the tank based on the calculated value.
2 Assignments
0 Petitions
Accused Products
Abstract
A leak detector comprising a sensor unit including a measuring slim-tube (13b) via the lower end of which a liquid in a tank is led in/out, a measuring tube (17) connected to the upper end thereof and having a sectional area larger than that thereof, and temperature sensors (133, 134) and a heater (135) provided to the slim-tube (13b), and a leak detection control unit (15a) connected to the sensor unit. The leak detection control unit (15a) has a pulse voltage generating circuit for applying a single pulse voltage to the heater (135) and a leak detecting circuit that is connected to the temperature sensors (133, 134) and produces an output equivalent to a temperature difference sensed by these temperature sensors, whereby a value equivalent to a liquid flow rate is calculated by integrating the difference between an output from the leak detecting circuit and its initial value according to a single pulse voltage applied to the heater (135) by the pulse voltage generating circuit, and leakage of liquid from the tank is detected based on this value.
29 Citations
31 Claims
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1. A leak detector of liquid in a tank, comprising:
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a measuring slim-tube into/from which the liquid in the tank is introduced or discharged through the lower end thereof; a measuring tube connected to the upper end of the measuring slim-tube and having a sectional area larger than that thereof; a sensor section additionally provided to the measuring slim-tube and including a first temperature sensor, a heater and a second temperature sensor arranged in this order along the measuring slim-tube, the sensor section measuring the flow rate of the liquid in the measuring slim-tube; and a leak detection control unit connected to the sensor section, wherein the leak detection control unit has a pulse voltage generating circuit for applying a single pulse voltage to the heater and a leak detecting circuit connected to the first and second temperature sensors and generating an output corresponding to a difference between temperatures detected by the first and second temperature sensors, and wherein the leak detection control unit integrates a difference between an output of the leak detecting circuit and its initial value in response to the application of the single pulse voltage to the heater which is performed by the pulse voltage generating circuit to calculate a value equivalent to the flow rate of the liquid to thereby detect leakage of the liquid in the tank based on the calculated value. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A leak detector of liquid in a tank, comprising:
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a measuring slim-tube into/from which the liquid in the tank is introduced or discharged through the lower end thereof; a measuring tube connected to the upper end of the measuring slim-tube and having a sectional area larger than that thereof; a flow rate sensor section additionally provided to the measuring slim-tube and including a first temperature sensor, a heater and a second temperature sensor arranged in this order along the measuring slim-tube, the flow rate sensor section measuring the flow rate of the liquid in the measuring slim-tube; a pressure sensor for measuring the level of the liquid; and a leak detection control unit connected to the flow rate sensor section and pressure sensor, wherein the leak detection control unit has a voltage generating circuit for applying a voltage to the heater and a leak detecting circuit connected to the first and second temperature sensors and generating an output corresponding to a difference between temperatures detected by the first and second temperature sensors, wherein the leak detection control unit performs a first leakage detection that detects leakage of the liquid in the tank based on the value equivalent to the flow rate of the liquid which is calculated using an output of the leak detecting circuit and a second leakage detection that detects leakage of the liquid in the tank based on the magnitude of a variation rate with respect to time of the level of liquid which is measured by the pressure sensor, and wherein the leak detection control unit outputs a result of the second leakage detection in the case where the magnitude of the liquid level variation rate with respect to time falls within a predetermined range in the second leakage detection, outputs a result of the first leakage detection in the case where the magnitude of the liquid level variation rate with respect to time falls below the lower limit of the predetermined range in the second leakage detection, and stops the output of a leakage detection signal in the case where the magnitude of the liquid level variation rate with respect to time falls above the upper limit of the predetermined range in the second leakage detection. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A leak detector of liquid in a tank, comprising:
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a measuring slim-tube into/from which the liquid in the tank is introduced or discharged through the lower end thereof; a measuring tube connected to the upper end of the measuring slim-tube and having a sectional area larger than that thereof; a flow rate sensor section additionally provided to the measuring slim-tube and including a first temperature sensor, a heater and a second temperature sensor arranged in this order along the measuring slim-tube, the flow rate sensor section measuring the flow rate of the liquid in the measuring slim-tube; a pressure sensor for measuring the level of the liquid; and a leak detection control unit connected to the flow rate sensor section and pressure sensor, wherein the leak detection control unit has a voltage generating circuit for applying a voltage to the heater, a leak detecting circuit connected to the first and second temperature sensors and generating an output corresponding to a difference between temperatures detected by the first and second temperature sensors, and an on-off valve provided in the upper portion of the measuring tube, and wherein the leak detection control unit detects the specific gravity of the liquid in the tank based on a value equivalent to the flow rate of the liquid which is calculated by using the output of the leak detecting circuit in a state where the on-off valve is closed, measures the level of the liquid by means of the pressure sensor by using the value of the specific gravity detected in the above to thereby perform a leakage detection of the liquid in the tank based on the magnitude of a variation rate of the level of the liquid with respect to time. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification