Refrigeration temperature and frost control

Claim 1

A METHOD OF CONTROLLING THE OPERATION OF REFRIGERATION APPARATUS WHICH INCLUDES COOLING MEANS ADAPTED WHEN ENERGIZED TO ABSORB HEAT FROM A REFRIGERATED ZONE, AT LEAST A PORTION OF SAID COOLING MEANS BEING SUBJECT TO FROST BUILD-UP, A FIRST RELAY ADAPTED TO ENERGIZE SAID COOLING MEANS, DEFROST MEANS ADAPTED WHEN ENERGIZED TO DEFROST SAID COOLING MEANS, A SECOND RELAY ADAPTED TO PREVENT ENERGIZATION OF SAID COOLING MEANS AND TO ENERGIZE SAID DEFROST MEANS, AND AN ELECTRICAL CIRCUIT INTERCONNECTED WITH SAID FIRST AND SECOND RELAYS AND THROUGH WHICH SAID RELAYS ARE SELECTIVELY ENERGIZED, SAID CIRCUIT INCLUDING CURRENT SWITCHING MEANS RESPONSIVE TO PULSES APPLIED THERETO FOR CONTROLLING THE CONDUCTIVITY OF SAID CIRCUIT; SAID METHOD COMPRISING: APPLYING OUT-OF-PHASE PULSES RESPECTIVELY TO SAID FIRST AND SECOND RELAYS, SENSING THE TEMPERATURE WITHIN SAID ZONE, APPLYING PULSES TO SAID CURRENT SWITCHING MEANS IN PHASE WITH THE PULSES APPLIED TO SAID FIRST RELAY TO CAUSE ENERGIZATION OF SAID FIRST RELAY BY CONDUCTION OF PULSES THROUGH SAID CIRCUIT WHEN THE TEMPERATURE WITHIN SAID ZONE HAS A PREDETERMINED RELATIONSHIP WITH RESPECT TO A PRESELECTED TEMPERATURE LEVEL, SENSING THE ACTUAL FROST BUILD-UP ON SAID COOLING MEANS, APPLYING PULSES TO SAID CURRENT SWITCHING MEANS IN PHASE WITH THE PULSES APPLIED TO SAID SECOND RELAY WHEN THE ACTUAL FROST BUILD-UP ON SAID COOLING MEANS EXCEEDS A PRESELECTED AMOUNT, TO CAUSE ENERGIZATION OF SAID SECOND RELAY BY CONDUCTION OF PULSES THROUGH SAID CIRCUIT, WHEREBY SAID FIRST RELAY CAUSES ENERGIZATION OF SAID COOLING MEANS WHEN THE TEMPERATURE WITHIN SAID ZONE RISES ABOVE SAID PRESELECTED TEMPERATURE LEVEL, AND SAID SECOND RELAY ENERGIZES SAID DEFROST MEANS AND PREVENTS ENERGIZATION OF SAID COOLING MEANS WHEN THE ACTUAL FROST BUILD-UP ON SAID COOLING MEANS EXCEEDS SAID PRESELECTED AMOUNT.

Claim 2

A METHOD OF CONTROLLING THE OPERATION OF REFRIGERATION APPARATUS WHICH INCLUDES COOLING MEANS ADAPTED WHEN ENERGIZED TO ABSORB HEAT FROM A REFRIGERATED ZONE, AT LEAST A PORTION OF SAID COOLING MEANS BEING SUBJECT TO FROST BUILD-UP, A FIRST RELAY ADAPTED TO ENERGIZE SAID COOLING MEANS, DEFROST MEANS ADAPTED WHEN ENERGIZED TO DEFROST SAID COOLING MEANS, A SECOND RELAY ADAPTED TO PREVENT ENERGIZATION OF SAID COOLING MEANS AND TO ENERGIZE SAID DEFROST MEANS, AND AN ELECTRICAL CIRCUIT INTERCONNECTED WITH SAID FIRST AND SECOND RELAYS AND THROUGH WHICH SAID RELAYS ARE SELECTIVELY ENERGIZED, SAID CIRCUIT INCLUDING CURRENT SWITCHING MEANS RESPONSIVE TO PULSES APPLIED THERETO FOR CONTROLLING THE CONDUCTIVITY OF SAID CIRCUIT; SAID METHOD COMPRISING: APPLYING OUT-OF-PHASE PULSES RESPECTIVELY TO SAID FIRST AND SECOND RELAYS, SENSING THE TEMPERATURE WITHIN SAID ZONE, APPLYING PULSES TO SAID CURRENT SWITCHING MEANS IN PHASE WITH THE PULSES APPLIED TO SAID FIRST RELAY TO CAUSE ENERGIZATION OF SAID FIRST RELAY BY CONDUCTION OF PULSES THROUGH SAID CIRCUIT WHEN THE TEMPERATURE WITHIN SAID ZONE HAS A PREDETERMINED RELATIONSHIP WITH RESPECT TO A PRESELECTED TEMPERATURE LEVEL, SENSING THE ACTUAL FROST BUILD-UP ON SAID COOLING MEANS, APPLYING PULSES TO SAID CURRENT SWITCHING MEANS IN PHASE WITH THE PULSES APPLIED TO SAID SECOND RELAY WHEN THE ACTUAL FROST BUILD-UP ON SAID COOLING MEANS EXCEEDS A PRESELECTED AMOUNT, TO CAUSE ENERGIZATION OF SAID SECOND RELAY BY CONDUCTION OF PULSES THROUGH SAID CIRCUIT, WHEREBY SAID FIRST RELAY CAUSES ENERGIZATION OF SAID COOLING MEANS WHEN THE TEMPERATURE WITHIN SAID ZONE RISES ABOVE SAID PRESELECTED TEMPERATURE LEVEL, AND SAID SECOND RELAY ENERGIZES SAID DEFROST MEANS AND PREVENTS ENERGIZATION OF SAID COOLING MEANS WHEN THE ACTUAL FROST BUILD-UP ON SAID COOLING MEANS EXCEEDS SAID PRESELECTED AMOUNT.