Gas detector
First Claim
1. A gas detector comprising:
- a main signal processing unit, including a main gas sensing element showing a change in electric resistance value to both target and non-target gases and putting out a first alarm driving signal by detecting that the target and non-target gas exceeds a first specified level;
a sub-signal-processing unit including (1) a circuit unit to give a second alarm driving signal when the detected target and non-target gas exceeds a second specified level of concentration set lower than the first specified level, through the use of the main gas sensing element; and
(2) a gate signal trigger unit for blocking the second alarm driving signal when the concentration of the non-target gas exceeds a third specified level, said gate signal trigger unit comprising an auxiliary gas sensing element showing a change in electric resistance in response to particularly non-target gas and a gate circuit unit coupled to the auxiliary gas sensing element; and
an alarm triggering means that is actuated by receiving the first or second alarm driving signal.
1 Assignment
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Accused Products
Abstract
A gas detector for detecting the leak of fuel gases, such as hydrogen gas, methane gas, butane gas, with improved reliability in detecting the gas leak. Said gas detector includes a main gas sensing element showing the change in resistance to target gases, such as methane, butane, hydrogen, as well as to non-target gases, such as alcohol, steam, smoke; an auxiliary gas sensing element showing change in resistance rather to non-target gas than to target gas; the first comparator receiving the output induced by resistance change in main gas sensor, as input; the second comparator with reference voltage set at lower level than that for the first comparator; and a gate circuit for blocking the alarm driving signal of the second comparator by the output induced by resistance change in auxiliary gas sensor. The output obtained from either said gate circuit or the first comparator is used for alarm driving signal of alarm circuit.
35 Citations
9 Claims
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1. A gas detector comprising:
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a main signal processing unit, including a main gas sensing element showing a change in electric resistance value to both target and non-target gases and putting out a first alarm driving signal by detecting that the target and non-target gas exceeds a first specified level; a sub-signal-processing unit including (1) a circuit unit to give a second alarm driving signal when the detected target and non-target gas exceeds a second specified level of concentration set lower than the first specified level, through the use of the main gas sensing element; and
(2) a gate signal trigger unit for blocking the second alarm driving signal when the concentration of the non-target gas exceeds a third specified level, said gate signal trigger unit comprising an auxiliary gas sensing element showing a change in electric resistance in response to particularly non-target gas and a gate circuit unit coupled to the auxiliary gas sensing element; andan alarm triggering means that is actuated by receiving the first or second alarm driving signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification