Portable gas analyser with time delay

Claim 1

A CONTROL CIRCUIT FOR A PROTABLE GAS ANALYSER HAVING A MEASURING CHAMBER, ELECTRICALLY OPERABLE PUMP MEANS FOR INDUCING A FLOW OF AMBIENT GAS INTO SAID CHAMBER, AN ELECTRICALLY OPERABLE MEASURING CIRCUIT FOR DETERMINING THE CONCENTRATION OF A COMPONENT OF THE GAS INDUCED INTO SAID CHAMBER, AND INDICATOR MEANS FOR PRODUCING A READING OF THE CONCENTRATION OF SAID COMPONENT, SAID CONTROL CIRCUIT COMPRISING: A SOURCE OF ELECTRIC CURRENT; A FIRST TIMER NETWORK CONNECTED BETWEEN SAID SOURCE AND SAID PUMP MEANS AND EMERGIZABLE FOR SUPPLYING SAID PUMP MEANS WITH ELECTRIC CURRENT FROM SAID SOURCE FOR A FIRST PREDETERMINED TIME PERIOD; A SECOND TIMER NETWORK CONNECTED WITH SAID FIRST TIMER NETWORK AND ENERGIZABLE THEREBY UPON THE DEACTIVATION OF SAID PUMP MEANS; AND A THIRD TIMER NETWORK CONNECTED WITH SAID SECOND TIMER NETWORK AND ENERGIZABLE THEREBY AFTER THE ELAPSE OF A PREDETERMINED DEALY PERIOD AND INTERPOSED BETWEEN SAID MEASURING CIRCUIT AND SAID SOURCE FOR CONNECTING SAID MEASURING CIRCUIT WITH SAID SOURCE FOR A SECOND PREDETERMINED TIME PERIOD.