摘要:
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.
摘要:
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.
摘要:
A leak detecting system includes a leak detector that detects leakage of liquid stored in a tank based on fluctuation in a level of the liquid. The leak detector includes a liquid inlet/outlet portion through which the liquid in the tank flows in and out, a flow-rate measuring unit configured to measure an amount of flow of the liquid inside the leak detector, and a liquid retaining portion configured to retain liquid flowing therein through the liquid inlet/outlet portion. A lower end of the leak detector is detachably attached to a bottom plate of the tank, and an upper end of the leak detector is supported in a gauging port in a top plate in such a manner that the leak detector is movable in a vertical direction.
摘要:
A leak detecting system includes a leak detector that detects leakage of liquid stored in a tank based on fluctuation in a level of the liquid. The leak detector includes a liquid inlet/outlet portion through which the liquid in the tank flows in and out, a flow-rate measuring unit configured to measure an amount of flow of the liquid inside the leak detector, and a liquid retaining portion configured to retain liquid flowing therein through the liquid inlet/outlet portion. A lower end of the leak detector is detachably attached to a bottom plate of the tank, and an upper end of the leak detector is supported in a gauging port in a top plate in such a manner that the leak detector is movable in a vertical direction.
摘要:
A fluid identification device includes a fluid detection part which is equipped with a temperature detector for fluid detection and a heating element disposed in the vicinity of the temperature detector and disposed on the identification target fluid side, a fluid detection circuit connected to the fluid detection part and an identification operation part which performs identification of an identification target fluid based on the output of the fluid detection circuit are contained in an identification sensor module main body.
摘要:
Measurements are obtained by a computing unit based on an output Vh from an indirectly-heated constant-temperature controlling flow rate measuring section (16) and an output Vout from a two-constant-point temperature difference detecting flow rate measuring sections (18a, 18b). In the flow rate measuring section (16), a heating element (163) is feedback-controlled based on a detected temperature by a heat sensing element (162) to obtain an output Vh based on the feedback-controlled condition. An output Vout is obtained from flow rate measuring sections (18a, 18b) based on the detected temperature difference between a heat sensing element (182) disposed on the liquid-flow-direction upstream side of the flow-rate measuring section (16) and a temperature sensing element disposed on the downstream side. A computing unit outputs as a measurement a flow rate obtained based on the output Vh in a flow rate region where a flow rate is larger than a predetermined boundary flow rate, and outputs as a measurement a flow rate obtained based on the output Vout in a flow rate region where it is less than a boundary flow rate. Accordingly, a flow rate is measured with good precision and sensitivity over a wide flow rate range from a trace-amount flow rate region to a comparatively large flow rate region.
摘要:
A device placed in a tank and used for detecting a leakage of liquid in the tank. Vertical measurement tube passages (10, 14) into which the liquid in the tank is introduced have a measurement tube (10) and a measurement thin tube (14). The measurement thin tube (14) communicates with the measurement tube and is located lower than the measurement tube. The measurement thin tube has a cross-sectional area that is equal to or smaller than {fraction (1/50)} of that of the measurement tube. A thermal flow sensor (16) used for measuring a liquid flow rate is attached to the measurement thin tube (14). There is provided leakage detecting means (22) for detecting a leakage of liquid in the tank according to the flow rate value measured by the sensor. The leakage detecting means generates a leakage detection signal when a flow rate value measured by the sensor is within a range greater than 0 and smaller than the flow rate value obtained when liquid is added to the tank or when the liquid in the tank is taken out. Thus, even a leakage of a very small amount is detected easily and accurately without stopping the use of the tank.
摘要:
A device placed in a tank and used for detecting a leakage of liquid in the tank. Vertical measurement tube passages (10, 14) into which the liquid in the tank is introduced have a measurement tube (10) and a measurement thin tube (14). The measurement thin tube (14) communicates with the measurement tube and is located lower than the measurement tube. The measurement thin tube has a cross-sectional area that is equal to or smaller than {fraction (1/50)} of that of the measurement tube. A thermal flow sensor (16) used for measuring a liquid flow rate is attached to the measurement thin tube (14). There is provided leakage detecting means (22) for detecting a leakage of liquid in the tank according to the flow rate value measured by the sensor. The leakage detecting means generates a leakage detection signal when a flow rate value measured by the sensor is within a range greater than 0 and smaller than the flow rate value obtained when liquid is added to the tank or when the liquid in the tank is taken out. Thus, even a leakage of a very small amount is detected easily and accurately without stopping the use of the tank.
摘要:
Measurements are obtained by a computing unit based on an output Vh from an indirectly-heated constant-temperature controlling flow rate measuring section (16) and an output Vout from a two-constant-point temperature difference detecting flow rate measuring sections (18a, 18b). In the flow rate measuring section (16), a heating element (163) is feedback-controlled based on a detected temperature by a heat sensing element (162) to obtain an output Vh based on the feedback-controlled condition. An output Vout is obtained from flow rate measuring sections (18a, 18b) based on the detected temperature difference between a heat sensing element (182) disposed on the liquid-flow-direction upstream side of the flow rate measuring section (16) and a temperature sensing element disposed on the downstream side. A computing unit outputs as a measurement a flow rate obtained based on the output Vh in a flow rate region where a flow rate is larger than a predetermined boundary flow rate, and outputs as a measurement a flow rate obtained based on the output Vout in a flow rate region where it is less than a boundary flow rate. Accordingly, a flow rate is measured with good precision and sensitivity over a wide flow rate range from a trace-amount flow rate region to a comparatively large flow rate region.
摘要:
Measurements are obtained by a computing unit based on an output Vh from an indirectly-heated constant-temperature controlling flow rate measuring section (16) and an output Vout from a two-constant-point temperature difference detecting flow rate measuring sections (18a, 18b). In the flow rate measuring section (16), a heating element (163) is feedback-controlled based on a detected temperature by a heat sensing element (162) to obtain an output Vh based on the feedback-controlled condition. An output Vout is obtained from flow rate measuring sections (18a, 18b) based on the detected temperature difference between a heat sensing element (182) disposed on the liquid-flow-direction upstream side of the flow rate measuring section (16) and a temperature sensing element disposed on the downstream side. A computing unit outputs as a measurement a flow rate obtained based on the output Vh in a flow rate region where a flow rate is larger than a predetermined boundary flow rate, and outputs as a measurement a flow rate obtained based on the output Vout in a flow rate region where it is less than a boundary flow rate. Accordingly, a flow rate is measured with good precision and sensitivity over a wide flow rate range from a trace-amount flow rate region to a comparatively large flow rate region.