This trainer allows the student to experiment with and control a Compound Two-Stage Compressor Application.  Compound multistage systems are typically used where ultra low temperatures are desired but cannot be economically obtained through the use of a single stage system.  This is because the compression ratios would be too high to get the necessary evaporating and condensing vapor temperatures.  In industrial applications these systems commonly produce temperatures between –29 deg C to –62 deg C for two stage systems and lower for three stage systems (down to – 93 deg C) 

In compound two-stage refrigeration systems low temperatures are obtained by using several compressors connected in series to the same refrigeration circuit.  Vapor in the evaporator of a low-temperature system has a high specific volume at a low temperature.  The first stage compressor is larger than the secondary stage compressor.  The refrigerant vapor is not condensed between compressors and an intercooler lowers the vapor temperature.  In each succeeding stage, the compressor is smaller in order to handle denser vapors and higher pressures. This increases the performance and efficiency of low-temperature systems as compared to single-stage systems.  The above diagram shows the layout and operation of the trainer 

TRAINER SPECIFICATIONS: 

FEATURES:  The components are clearly laid out in a manner similar to a refrigeration circuit diagram and are mounted onto a mobile steel stand that incorporates a work surface.  The refrigeration circuit is displayed on a colorful silk-screened diagram.  Refrigeration pipes are color coded to indicate the state of the refrigerant within the circuit.  Sight glasses monitor the refrigerant state along with strategically placed pressure gauges, hand valves allow the system to be controlled and malfunctions to be introduced, courseware includes student job sheets. 

MAIN COMPONENTS: Two Compressors (First Stage: 1Hp, Second Stage:3.0pt/4Hp), one air cooled condenser, one forced fan evaporator with cabinet (chamber insulation rating of –70 deg C), one intercooler, one Thermostatic Expansion Valves (TEV), one high side float between stages, one oil separator, one Receiver, one Filter/dryer, Sight Glasses, one Solenoid Valve, High Pressure Control, Low Pressure Control, one Thermostat,  eight pressure gauges, one Relief Valve, Set of Hand Valves for Control. Instrument panel has system controls along with voltmeter and ammeter.  Unit will achieve temperature of between -40 to -45 deg C. 

OPTIONAL ACCESSORIES: 

RCO-CRS-A: Flow meter for viewing flow rate of refrigerant.

RCO-CRS-B: Variable speed fan for evaporator or condenser

RCO-CRS-C: 10 electrical faults with electrical circuit panel.

RCO-CRS-D: 12 point Digital Temperature meter with channel selector switch.