Combustible gas detecting device

Patent metadata

Field	Value
Publication number	US-9279795-B2
Application number	US-201313942147-A
Country	US
Kind code	B2
Filing date	Jul 15, 2013
Priority date	Jul 17, 2012
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

Abstract

A flammable gas concentration detection apparatus ( 1 ) including an energization control unit ( 50 ) that switches the energization state of heating resistor ( 34 ) at regular time periods TW, and a gas concentration computation unit ( 7 ). The heating resistor has first and second set temperatures CH and CL. The voltage detected across the heating resistor at the first and second set temperatures corresponds to a high and low temperature voltage, respectively. The gas concentration computation unit computes the concentration of a flammable gas based on a first information group including an average high temperature voltage averaging the values of two temporally successive high temperature voltages, the low temperature voltage in a period of time between two high temperature voltages, and an environment temperature in the period of time in which the low temperature voltage is detected.

First claim

The invention claimed is:

1. A flammable gas detection apparatus comprising:
a heating resistor disposed in an atmosphere for detection and whose resistance value is changed in response to a temperature change in the heating resistor;
an energization control unit that performs control to switch an energization state of the heating resistor at regular periods of time so that the heating resistor has resistance values respectively corresponding to preset two set temperatures;
a temperature-measuring resistor whose resistance value is changed by a change in an environment temperature which is the temperature in the atmosphere for detection; and
a gas concentration computation unit that computes a concentration of flammable gas in the atmosphere for detection by using a voltage across the heating resistor that is detected at the time of energization of the heating resistor by the control by the energization control unit, and the environment temperature based on a voltage change caused by a change in the resistance value of the temperature-measuring resistor,
wherein:
the two set temperatures include a first set temperature on a high temperature side and a second set temperature on a low temperature side;
the voltage across the heating resistor that is detected at the first set temperature is a high temperature voltage, and the voltage across the heating resistor that is detected at the second set temperature is a low temperature voltage; and
the gas concentration computation unit computes the concentration of the flammable gas based on a first information group including an average high temperature voltage averaging the values of two temporally successive high temperature voltages, the low temperature voltage in a period of time between the two high temperature voltages, and the environment temperature in the period of time in which the low temperature voltage is detected, or a second information group including an average low temperature voltage averaging the values of two temporally successive low temperature voltages, the high temperature voltage in a period of time between the two low temperature voltages, and the environment temperature in the period of time in which the high temperature voltage is detected.

2. The flammable gas detection apparatus as claimed in claim 1 , wherein the gas concentration computation unit uses, as the low temperature voltage in the first information group, the second one of the two temporally successive low temperature voltages in the second information group, and, as the high temperature voltage in the second information group, the second one of the two temporally successive high temperature voltages in the first information group.

Assignees

• Ngk Spark Plug Co

Inventors

• Matsukura Yusuke
• Kitanoya Shoji
• Watanabe Masaya

Classifications

• G01N27/18

  caused by changes in the thermal conductivity of a surrounding material to be tested (G01N27/20 takes precedence) · CPC title

• G01N33/0036 Primary

  specially adapted to detect a particular component (physical analysis of gaseous biological material G01N33/497) · CPC title