Combustion efficiency measuring appts. for fossil fuel appliances - has sensors producing outputs of temp. and flue gas concn. provided by computation circuit

摘要

The apparatus is for measuring appliance combustion efficiency and comprises sensors (5,3) for producing output signals which vary with the temperature and the concentration of a constituent gas e.g. oxygen of the flue gases. A microprocessor-based computation circuit (10) is arranged to derive measurement values of the measured temperature and constituent gas concentration, from the two sensors and to apply these measurement values in the computation of a predetermined formula relating the stack loss or efficiency to the measured quantities. The apparatus is arranged to automatically calibrate the or each sensor from a test measurement prior to deriving the measurement values. This may be achieved in the case of a sensor having a non-linear response, by performing a calculation of a formula defining the non-linear response of the sensor using a co-efficient derived from the test measurement. The sensor is automatically calibrated and linearised from a single test measurement. The predetermined efficiency formula may be modified for different types of fuel, and temperature and oxygen or carbon dioxide values used in the calculation.