Refrigeration Screw Compressors

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
  • Intergral 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 gray iron, Stress relieved & 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 suc-tion 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 & 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 & 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 compress-sor. The discharge of this compressor approximately at 25 psi, is intercooled & sent to the High stage compressor. The Boosters are good power saver & 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. Al-gorithms that provide improved protection against motor overloading, high ampere draw, low suction 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. 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 & discharge stop & check valves. Suction strainer-60-mesh-ensures low pressure drop. Take – apart Thermal Ex-pansion Valves, Solenoid valves & liquid line filter/driers allow ease of maintenance. All piping as pre ASME B 31.5, Pressure tested, evacuated & charged with refrigerant.

Evaporator & Condensor
  • For R22- Shell & 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 & other gases.
  • Condenser: 3/4” OD Tubes are cleanable & 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 & headers materials available to customer preference & design requirements.
  • The condenser & Evapor , 1tors 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.

Piping
Oversized suction & discharge stop & check valves. Suction strainer-60-mesh-ensures low pressure drop. Take – apart Thermal Ex-pansion Valves, Solenoid valves & liquid line filter/driers allow ease of maintenance. All piping as pre ASME B 31.5, Pressure tested, evacuated & charged with refrigerant.

Evaporator & Condensor
  • For R22- Shell & 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 & other gases.
  • Condenser: 3/4” OD Tubes are cleanable & 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 & headers materials available to customer preference & design requirements.
  • The condenser & Evapor , 1tors 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.
The Chart below gives the capacity (TR) to input power (KW) required TR/KW at various evaporating temperatures for R-22 & R-171. (These machines are suitable up to minus 50C evaporating temperature also contact the manufactures for details.)

GAS R-22


GAS R-717

Above capacities of CSI screw compressors are at 35 condensing.




Complete package units prewired, prepiped, pressure tested, run tested ready to install.

Custom facrication of disassembled packages for easier assembly into place due to space constrains or easier rigging into place onboard vessel. Ratings of CSI Screw compressors with economizer.















GAS R-22
Ratings of CSI Screw compressors with economizer


GAS R-717

Above capacities of Economised CSI screw compressors are at condensing 35


SCREW CHILLER PACKAGE FOR AIR-CONDITIONING
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 give 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.



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