Refrigeration Screw Compressors
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Description
Refrigeration screw compressors are a type of compressor commonly used in industrial refrigeration systems. They are designed to compress refrigerant gas by using two helical rotors or screws. These compressors are known for their efficiency, reliability, and ability to handle varying capacity requirements.
The screw compressors work by trapping the refrigerant vapor between the rotors, compressing it as the rotors rotate, and then discharging the high-pressure gas. This process allows for continuous compression, making them suitable for applications where a constant supply of compressed refrigerant is needed.
Screw Chiller Package for Air-conditioning
Colt is the leading manufacturers and Suppliers of refrigeration screw compressors. Colt Screw chiller packages are pre- wired, pre-piped, pressure tested, run tested ready to install. The capacities of the various models are indicated in the chart below. These units come with Microprocessor Controls which are Easy to use. Single function keypad with a large character backlit displays exactly the data you need. Algorithms that provide improved protection against motor overloading, high ampere draw, low suction pressure, high discharge pressure, freeze protect low oil psi & unsafe suction. The Microprocessor controller will keep the system running at its most optimum level. Dynamic adjustments are made based on low suction psi, high motor amps, high discharge psi, high oil temperature, low ambient, status on all operations both locally & remotely. History, static and dynamic graphing is standard to aid in commissioning, trouble shooting and evolution. The chart below gives the capacity of the CSI Screw chillers used for air conditioning on R-22. The water Temperature into the chiller of the CSI Screw & out from the chiller at 80C. The Colt Screw compressors can also use R-134a, R-717 & other new generation gases, the capacity & power consumption will change, Refer Colt for data on other gases.
Refrigeration Screw Compressors
Being the top dealers and Suppliers of refrigeration screw compressors. Colt screw compressors are state-of- the-art new generation twin-screw oil injected machines with open-drive specially designed & developed for refrigeration & Air-conditioning applications. Compression is obtained by intermeshing rotors of asymmetric profile; the rotors turn in an outward direction forcing the male & female flutes to un-mesh allowing the gas to enter the top of the machine. The gas will travel around the outside of the rotor until ii reaches the bottom where compression actually occurs; the gas is released through the opening in the discharge port. The Rotor used in Colt compressors is of 4+6 SRM asymmetric profile.
Lubricating System
- Oil separation system-efficient multi stage coalescing system is separate from the compressor. Serviceable without removing compressor, chiller, condenser. The oil carries over is maximum 5 PPm
- Integral built in oil heater maintains oil temperature for start up
- Rotary oil pumps ensure positive lubrication to bearings for start up
Compressor
- Open drive positive displacement oil injected, twin Rotary suitable for low evaporation temperature up to minus 50 degree centigrade.
Casting
- Made from graded grey iron, Stress relieved and machined on CNC Machines.
Rotors
- Machined from High tensile carbon steel, on imported Rotor cutting machines, dynamically balanced.
Oil Cooling
- Water Cooling of Lub. Oil is standard with shell and tube type heat exchanger.
- Liquid Refrigerant Injection system available on demand.
Bearings
- Generously oversized cylindrical roller bearing on the suction end for radial loads and double row taper roller bearings on discharge end for radial and axial thrust.
Choice of Refrigerant
- Flexibility in meeting environment requirements, R22/R717 are the commonly used refrigerants.
- Suitable for other new generation Refrigerants like R-134a/R404a and other refrigerants also.
Shaft Seal
- Mechanical balanced, face type with Rotating Carbon Steel and oil Lubricated. The shaft seal is replaceable without re-moving the compressor or Motor.
Capacity Control
- A built-in slide below the rotors provides steeples capacity control down to 10%, of full load capacity, which results in considerable saving on power. The slides move to and from by an inbuilt hydraulic cylinder. Automatic control adjusts the position of the slide to reduce/increase the capacity of the compressor to match with the varying requirements.
Compressor/Motor drive couplings
- Spacer type two-piece flexible coupling with metallic elements allow for in place replacement of coupling and compressor seal.
Drive Motor
- Two pole, SPDP or TEFC 3 phase 50 cycles 415 volts class ‘F’ insulations foot mounted as per IS-325
- Economizer
- These compressors also have a side port for Economizer or sub cooling Circuits Used for low and ultra-low temperature. This feature is only available in Screw compressors. Refer chart.
Booster
- For low temperatures a combination of two screw compressor is used where in the first compressor is known as booster compressor. The discharge of this compressor approximately at 25 psi, is intercooled and sent to the High stage compressor. The Boosters are good power saver and are widely used in tunnel freezers.
Controls
- Easy to use microprocessor controls. Single function keypad with a large character backlit displays exactly data you need. Algorithms that provide improved protection against motor overloading, high ampere draw, low suction pressure, high discharge pressure, freeze protect low oil psi and unsafe suction. The Microprocessor controller will keep the system running at its most optimum level. Electromechanical controls can be provided too.
Ability to Handle Liquid
- An important feature oil screw compressor is the ability to handle volume’s oil liquid without any damage to machine, matched neither by the reciprocating nor by centrifugal compressors.
Piping
- Oversized suction and discharge stop and check valves. Suction strainer-60-mesh-ensures low pressure drop. Take – apart Thermal Ex-pension Valves, Solenoid valves and liquid line filter/driers allow ease of maintenance. All piping as pre ASME B 31.5, Pressure tested, evacuated & charged with refrigerant.
Evaporator and Condenser
- For R22- Shell and tube type with removable head allow total maintenance. ASME Section Vlll Div. l Construction. Tube are Roll expanded in to tube sheets. Suitable for R-22, R-717 and other gases.
- Condenser: 3/4” OD Tubes are cleanable and removable, Integral fin design maximizes condensing performance.
- Evaporator: 1/2'” to 3/4" tube are used with turbulators for high efficiency. Choice of Shell, baffle, tubes, turbulators and headers materials available to customer preference and design requirements.
- The condenser and Evaporators are mounted on the skid for compactness & saving of space.
Typical Applications
- Air conditioning, Heat pumps, Bulk drug plants, Pharmaceuticals and Chemical, Petrochemicals and Fertilizer, Cold Storage, Ice Rinks, Cooling Plants, Water Chilling, Refrigeration Plants for Food Freezing, Marine Refrigeration, Milk Dairies.
Ability to Handle Liquid
- An important feature oil screw compressor is the ability to handle volume’s oil liquid without any damage to machine, matched neither by the reciprocating nor by centrifugal compressors.
