Air conditioning apparatus comprising refrigerant shortage sensor

An air conditioning apparatus including a motor driven compressor and a refrigerant reservoir connected to the compressor, characterized by comprising:

• level sensor means for producing an electrical signal when a refrigerant level in the reservoir is below a predetermined value;
• level switch means for normally controlling the compressor to be motor driven and for controlling the compressor to be to be not motor driven in response to the electrical signal;
• delay means connected between the level sensor means and the level switch means for delaying the electrical signal for a predetermined length of time;
• and
• operation sensor means for sensing motor operation and enabling the sensor means only in response thereto;
• the delay means comprising a time constant circuit including a resistor and a capacitor, the operation sensor means comprising means for discharging the capacitor in response to motor non-operation.

An air conditioning apparatus including a motor driven compressor and a refrigerant reservoir connected to the compressor, characterized by comprising:

• level sensor means for producing an electrical signal when a refrigerant level in the reservoir is below a predetermined value;
• level switch means for normally controlling the compressor to be motor driven and for controlling the compressor to be not motor driven in response to the electrical signal;
• delay means connected between the level sensor means and the level switch means for delaying the electrical signal for a predetermined length of time;
• temperature sensor means for controlling the compressor to be motor driven only when a sensed temperature is above a predetermined value;
• the delay means comprising a time constant circuit including a resistor and a capacitor, the temperature sensor means comprising means for discharging the capacitor when the sensed temperature is below the predetermined value.

An air conditioning apparatus including a motor driven compressor and a refrigerant reservoir connected to the compressor, characterized by comprising:

• level sensor means for producing an electrical signal when a refrigerant level in the reservoir is below a predetermined value;
• level switch means for normally controlling the compressor to be motor driven and for controlling the compressor to be not motor driven in response to the electrical signal;
• delay means connected between the level sensor means and the level switch means for delaying the electrical signal for a predetermined length of time;
• and
• temperature sensor means for controlling the compressor to be motor driven only when a sensed temperature is above a predetermined value;
• the temperature sensor means comprising a thermal switch which is connected in series with the level switch means.