| 摘要 |
PURPOSE:To monitor a gas appliance whether combustion is performed or raw gas is leaking without burning, by detecting the flow rate of gas and by observing the changing pattern with time in flow rate. CONSTITUTION:The primary calculator 6 calculates the flow rate, and a result is stored in a memory 7 each time after calculation, while a counter 9 adds 1 to the content stored in it. In such a manner, calculation is continued. When the primary calculator finished calculation on the predetermined number of time, that is the Nth time, the data from the first flow rate F1 to the flow rate FN on the Nth time has been stored in the memory 7. As the content in the counter 9 gets to N, it outputs a signal to start calculation. Receiving the signal, the secondary calculator 10 calculates the rate of change DELTAF=(F-FN)/F1, and the result is outputted. A comparator 12 compares the rate of change DELTAF with a reference value DELTAFa from a reference value generator 11, and when a result is DELTAF<DELTAFa, a non-combustion signal is outputted. |
