Abstract: A system for modulating refrigerant flow from an evaporator of an air or gas drying apparatus wherein the air or gas drying apparatus has an evaporator shell with at least one exit orifice for return of refrigerant to an accumulator or compressor. The system comprising a flow metering structure connected to the at least one exit orifice, the structure having an internal tube with a vertical rise from an evaporator shell end to an accumulator or compressor end, the internal tube having at least one return orifice (a) which allows passage of liquid refrigerant outside the internal tube into the internal tube, and at least one return orifice (b) which allows passage of gas outside the internal tube into the internal tube.

Abstract: An apparatus and method of use for effectively purging desiccant air dryers of moisture load by introducing heated purge air into the containment vessel holding the desiccant, directly into those areas of the desiccant bed where the moisture loads are most heavily saturated. The improved heat regenerated desiccant gas dryer utilizes parallel ports for introducing heated air or an internal heat distributor, the former automatically controlled by valves selectively operated to allow purge air to quickly cause water vapor adsorbed by the desiccant to be released and discharged from the vessel, allowing the dryer to be returned to service in the gas drying mode with greater confidence that undesirable dew point spikes have been eliminated. More efficient use of heated purging air enables shorter turn-around times for the dryer and energy savings.

Abstract: A refrigeration system including a compressor, condenser, thermal expansion valve, control for the thermal expansion valve, shell evaporator, suction line between the shell evaporator and compressor, and a control evaporator in the suction line between the shell evaporator and the control for the thermal expansion valve utilizing hot refrigerant gas from the compressor to heat the refrigerant in the suction line. The refrigeration system also includes an unloading arrangement for the compressor. In one arrangement a hot loop circuit is located directly between the outlet of the compressor and the inlet thereof and a cold loop circuit is located between the outlet and inlet of the compressor and which includes the evaporator, and both loops bypass the condenser and thus pass refrigerant from the compressor back to the compressor to thereby permit it to selectively operate in an unloaded condition in response to the load applied by the medium which is being cooled.

Abstract: A halocarbon refrigeration system including a compressor, condenser, thermal expansion valve, control for the thermal expansion valve, shell evaporator, suction line between the shell evaporator and compressor, and a control evaporator in the suction line between the shell evaporator and the control for the thermal expansion valve, the control evaporator utilizing hot refrigerant gas from the compressor to heat the refrigerant in the suction line and thus expose the control for the thermal expansion valve to heated refrigerant which in turn causes the thermal expansion valve to admit more liquid refrigerant to the shell evaporator to cause it to operate in a fully flooded condition, the control evaporator also insuring vaporization of all the liquid in the suction line prior to its passage to the compressor.

Abstract: A sensing element for controlling the unloading of a compressor including a finned tube for placement in firm heat conducting engagement within a tube of a shell evaporator and containing a thermocouple which senses either the temperature of fluid within the tube or the temperature of the refrigerant on the outside of the tube which is located within the evaporator, depending on the amount of fluid flowing through the tube.