TEMPERATURE ACTUATED AIR FLOW CONTROL AND GAS SAMPLER

摘要

A temperature actuated air flow control comprises a fluid inlet for the gas sample which is connected to an exhaust line through an intermediate venturi chamber into which a gas such as air is vented in order to aspirate the flow of the gas through the inlet to the exhaust. The amount of flow of the aspirating gas controls the quantity of flow of the sample gas through the inlet to the exhaust. A valve chamber in the aspirating gas passage comprises a bimetallic plate which is flexed between a position in which it closes a flow passage for the aspirating gas to one in which it opens the passage. The bimetallic plate is flexed by temperature change. The device advantageously functions to provide for the inflow of a sample or test quantity of a gas and flows through a chamber having a gas sensor to determine the characteristics of the gas and is directed through a venturi section and out through an exhaust. An aspirating gas such as air is directed into the venturi section and its quantity is controlled by the bimetallic element. In a correct operating temperature the bimetallic element will be flexed to open the passage and permit the continuous sampling of the gas but if the temperature falls for example to a temperature which is below the dew point of the sample gas the bimetallic element may be chosen so as to close off the aspirating air and stop the testing at that time.