Volume-variation measuring and recording apparatus

Claim 1

A COMBINATION FOR MEASURING MINUTE VOLUME CHANGES IN A CLOSED GAS SYSTEM CONSISTING OF A CYLINDER CONTAINING A GAS OF A GIVEN COMPOSITION, A PISTON RECIPROCABLY MOUNTED IN SAID CYLINDER AND SEALING ONE END THEREOF, A RACK GEAR CARRYING SAID PISTON, A CHAMBER COMMUNICATING WITH THE OPPOSITE END OF SAID CYLINDER IN WHICH A GAS VOLUME CHANGE REACTION IS TAKING PLACE, A FLUID RESERVOIR PROVIDED WITH A PORT, A CONNECTING FITTING THROUGH SAID PORT EXTENDING ABOVE THE FLUID LEVEL IN SAID RESERVOIR, A COUNTERBALANCED INVERTED CUP MEMBER DISPOSED IN SAID RESERVOIR AROUND SAID CONNECTING FITTING, SAID CUP MEMBER COMMUNICATING THROUGH SAID FITTING WITH SAID CYLINDER AND SAID CHAMBER THROUGH THE OPEN BOTTOM END OF THE CUP AND THROUGH SAID PORT, A LIGHT SOURCE AND PHOTOSENSITIVE RESISTOR MOUNTED ON SAID RESERVOIR, AN OPAQUE SCREEN MOUNTED ON SAID CUP MEMBER BETWEEN SAID LIGHT SOURCE AND SAID PHOTOSENSITIVE RESISTOR, A POWER SUPPLY AND DRIVE MOTOR, AN ELECTRICAL NETWORK CONNECTED TO SAID PHOTOSENSITIVE RESISTOR AND SAID DRIVE MOTOR, A POLARIZED RELAY AND A VOLTAGE DIVIDER CONNECTED TO SAID NETWORK TO DRIVE SAID RACK GEAR AND PISTON RECIPROCABLY WITH SAID MOTOR IN RESPONSE TO MINUTE GAS VOLUME CHANGES DETECTED BY MOVEMENT OF SAID INVERTED CUP MEMBER, A RECORDING PEN MOUNTED ON SAID RACK GEAR OUTSIDE OF SAID CYLINDER, SAID PEN PIVOTABLE TRANVERSE TO THE DIRECTION OF RACK GEAR AND PISTON TRAVEL IN SAID CYLINDER, A PIVOTABLE U-SHAPED LIFTING BAR AGAINST WHICH SAID RECORDING PEN RESTS AND A TIMING MOTOR AND ASSOCIATED CAM IN CONTACT WITH SAID LIFTING BAR TO MOVE SAID LIFTING BAR AND RECORDING PEN AT REGULAR TIME INTERVALS TRANVERSE TO THE DIRECTION OF PEN AND PISTON TRAVEL.