Patent ID: 8956153
Filing Date: 2015-02-17
Classification: F23N

Abstract:
1. A security device for a combustor, which burn gas, to determine an oxygen concentration around the combustor, comprising: a gas valve which is controlled by electrical signals to provide gas to the combustor; a thermocouple provided beside the combustor to generate a thermoelectric potential because of a heat of the combustor, wherein the thermoelectric potential is directly proportional to the heat of the combustor; and a controller electrically connected to the gas valve and the thermocouple, wherein the controller receives the thermoelectric potential from the thermocouple and controls the gas valve accordingly; wherein the controller compares the thermoelectric potential with a low level, and controls the gas valve to stop the gas supplied to the combustor while the thermoelectric potential is lower than the low level; wherein the controller compares the thermoelectric potential with a high level, and partially closes the gas valve to reduce the gas supplied to the combustor while the thermoelectric potential is lower than the high level and is higher than the low level; wherein the low level is a predicted potential value, which indicates insufficient oxygen in the environment, and the high level is a predicted potential value too, which indicates sufficient oxygen in the environment; wherein the thermoelectric potential decreases along with less oxygen around the combustor.