Apparatus for maintaining a testing fluid at a selected temperature

Claim 1

APPARATUS FOR MAINTAINING AT A SELECTED TEMPERATURE A LIQUID FOR TESTING AND CALIBRATING INSTRUMENTS COMPRISING IN COMBINATION, A RECEPTACLE HAVING A CERTAIN HEIGHT AND HAVING AN OPEN TOP, LIQUID IN SAID RECEPTACLE, A REFRIGERANT CONDUCTING CONDUIT IN SAID RECEPTACLE ADJACENT TO AND OVERLYING THE INNER SURFACE OF THE WALL OF THE RECEPTACLE, A VERTICALLY EXTENDING FORAMINOUS SHIELD IN THE RECEPTACLE SURROUNDED BY SAID CONDUIT, SAID SHIELD BEING OPEN AT THE TOP AND AT THE BOTTOM AND ENCLOSING AN AREA INTO WHICH AN INSTRUMENT MAY BE INTRODUCED INTO THE LIQUID FOR TESTING, THE CONDUIT AND SHIELD BEING SPACED FROM THE BOTTOM OF THE RECEPTACLE, SAID COIL BEING ADAPTED TO HAVE A REFRIGERANT CIRCULATED THERETHROUGH, A ROTARY IMPELLER SUPPORTED BENEATH SAID SHIELD IN THE SPACE BETWEEN THE SHIELD AND THE BOTTOM OF THE RECEPTACLE, SAID IMPELLER BEING ADAPTED WHEN ROTATED IN ONE DIRECTION TO DRAW LIQUID DOWN FROM SAID SPACE THROUGH THE BOTTOM OF THE SHIELD AND IMPELL IT UPWARD OVER SAID CONDUIT BETWEEN THE SHIELD AND RECEPTACLE WALL, ELECTRICAL DRIVING MEANS FOR ROTATING SAID IMPELLER, ELECTRICAL HEATING MEANS UPON THE OUTER SIDE OF THE RECEPTACLE FOR HEATING THE LIQUID, AN ELECTRICAL RESISTANCE SENSING DEVICE EXTENDING INTO THE RECEPTACLE TO THE APPROXIMATE CENTER THEREOF BETWEEN THE LOWER END OF THE FORAMINOUS SHIELD AND SAID IMPELLER, ELECTRIC CIRCUITRY HAVING MEANS FOR CONNECTION WITH A SOURCE OF ELECTRIC POTENTIAL AND HAVING SAID HEATING MEANS, SAID SENSING MEANS AND SAID IMPELLER DRIVING MEANS THEREIN, OTHER ELECTRIC RESISTANCE HEATING MEANS CONNECTED WITH SAID CIRCUITRY AND POSITIONED TO HEAT THE RESISTANCE SENSING MEANS WHEN ENERGIZED, MEANS ACTUATED BY THE SENSING MEANS FOR EFFECTING ACTUATION OF THE FIRST SAID HEATING MEANS AND SAID OTHER ELECTRICAL RESISTANCE MEANS WHEN THE TEMPERATURE OF THE LIQUID FALLS BELOW A PREDETERMINED TEMPERATURE WHILE SAID COOLING MEANS IS FUNCTIONING TO PREVENT THE TEMPERATURE OF SAID LIQUID RISING ABOVE SAID PREDETERMINED TEMPERATURE, WHEREBY THE TEMPERATURE OF SAID LIQUID IS PREVENTED FROM RISING ABOVE SAID PREDETERMINED TEMPERATURE AN AMOUNT EQUAL TO SAID PREDETERMINED TEMPERATURE.