A long and accurate development of the project and the FRASCOLD experience, grant us the chance to propose a reliable range of semi-hermetic two stage compressors. FRASCOLD two stage compressors are particularly suitable to operate with refrigerants R404A, R507A and R22. They are efficient and reliable in a wide application range. Two stage compressor range consists of 8 models with displacement (measured on low pressure side) from 30.26 m3/h to 123.50 m3/h and refrigerating capacity from 1720 W to 59570 W. They are suitable to operate with evaporating temperature from -20°C down to -70°C.

The main features of two stage compressors are:

• Optimal mass distribution to grant a extremely quiet and smooth running
• Shaft with specific heat treatment
• Piston shape optimization
• Chromium-plated rings to reduce friction and oil circulation
• Only for V and Z series compressors; lubrication by means oil pump with reversible type gear
• Particularly sized valve plate to optimize the efficiency in both stage
• Electric motor designed to get high efficiency and protection to winding overheating
• Injection valve that directly regulates the discharge temperature of second stage by means refrigerant injection; such a way, high pressure side temperature is held with the set value.

Standard equipment

The compressors are supplied with:

• Suction and discharge valves, sweat connection type
• Rubber vibration absorbers
• Valve for liquid injection into the interstage
• Lubricant charge
• Nitrogen holding charge (1 bar) to protect them against humidity
• oil sight glass,
•  only for V and Z series compressors, high discharge temperature protection by means electronic module

All compressors are coated with anti-rust protective primer and blue enamel coat.

Accessories

On request, compressors can be supplied with following accessories assembled in factory:

• Kit for liquid subcooling complete with heat exchanger, solenoid valve on the liquid injection piping, sight-glass, filter-dryer and thermostatic expansion valve for liquid injection
• Only for S series compressors, high discharge temperature protection device
• Only for compressor equipped with oil pump, oil pressure switch either electronic type or  electromechanical type
• Crankcase heater

Efficiency

Optimization of energy efficiency has been achieved by means of an accurate selection of electric motor, design and machining of mechanical parts. Close examination of refrigerant flow dynamism and its behavior during refrigeration cycle, affected the designing of each mechanical part such as cylinder heads, valve plates etc.

Low noise

Improvement carried out to increase efficiency has an additional bonus of extremely quiet and smooth running even at heavy operating conditions.

Refrigerating capacities

Capacities are calculated at 60Hz (1740 RPM) liquid subcooling as shown in capacity tables, ambient temperature 32°C, with suction gas at 20°C for all refrigerants. Electronic catalog is available; software that features all the data introduced in this catalogue and allows selecting the correct product according to the specific operating conditions. Softwares are available to all users of FRASCOLD products.

Electrical protection

All compressors are supplied with thermistors integral protection completed with electronic control module KRIWAN INT69 (INT69TM for V and Z series).