Thursday, December 25, 2008

Rotary Compressor Coolant

Rotary Compressor Coolant

Lubricant for Oil-Flooded Rotary Screw and Vane Air Compressors


The Rotary Compressor Coolant represents a “step-change” advance in lubricating oils specifically developed for oil flooded rotary screw and vane air compressors. They are premier quality products, highly recommended for both static and mobile plant with working temperatures up to 120 degree C.

The products are based on HVI paraffinic base oils, treated to reduce the polycyclic aromatic content, into which are blended additives to impart anti-oxidant, anti-wear, anti-corrosion, anti-foam and dispersions properties.

Extended field evaluations have demonstrated a vastly superior performance, to the extent that oil drain periods may be doubled. This effectively means an increase from the current maximum of 2000 hours to 4000 hours at a continuous maximum air discharge temperature of 100 degree C.
Combined with the extended life is a facility to keep the internal surfaces completely free from deposits whilst maintaining a steady differential pressure (dp) across the separator/coalescer. This means that premature blockage of separators/coalescers are eliminated.



Outstanding oxidation and thermal stability, which serves to extend the service life even with bulk oil temperatures up to 120 degree C.

Reduced maintenance cost resulting from the doubling of intervals between oil changes.

Excellent cleanness properties, eliminating the blockage of separators/coalescers.

Good protection against corrosion, extending the life of components in service.

Limited carry over of oil into the air stream, offering high quality process air.

Reduced risk of fire in the separator pack, due to the excellent oxidation and thermal stability of the oil.

Good anti-foam properties to suppress the tendency to foam excessively in service.

Good air release properties to minimize or avoid cavitations effects and increased compressibility.

The Rotary Compressor Coolant has been specifically developed to cater for the lubrication requirements of the complete spectrum of rotary screw and vane air compressors.

They are applicable to all types and sizes of rotary vane and screw air compressor whether oil flooded or oil injected, male or female drive, single or two stage configurations.

Although primarily designed for static industrial application, the coolant is equally applicable to the lubrication of air end in mobile plant configurations.

Oxidation Stability:

Oxidation can be considered the most important single property of oil for rotary compressors, since it is this, which primarily determines the useful life of the oil and its resistance to thickening and to the formation of carbonaceous deposits.

The excellent oxidation stability of the Rotary Compressor Coolant makes it possible to operate compressors continuously for long periods between oil changes, and at higher temperatures without the need to resort to highly price synthetic lubricants.

The IP 280 and IP 306 test results confirm the outstanding oxidation stability of the Rotary Compressor Coolant, in particular the very low ratios of sludge to TOP (total oxidation products) of 2.54% and 2.15% respectively against a permissible maximum of 40%.


The ability of compressor oil to resist foaming is important, since malfunctioning of the compressor can occur if excessive amount of foam is allowed to form in the separator.

Tests have proved that the special additive combination in the Rotary Compressor Coolant reduces the tendency of the oil to foam in the separator.
Typical results in terms of IP 146 – the Foaming Characteristics of Lubricating Oil:

Sequence 1 10/NIL (Foaming Tendency/Foam Stability)
Sequence 2 Nil/NIL (Foaming Tendency/Foam Stability)
Sequence 3 20/NIL (Foaming Tendency/Foam Stability)

Protection Against Corrosion:

The occasional presence of water in oil-flooded compressor systems is possible, so it is important that the oil gives protection against corrosion. In addition to the associated mechanical problems, fine particles of rust dispersed in the oil will reduce the oxidation stability of the oil considerably and will also adversely affect its air release properties.

The Rotary Compressor Coolant have excellent corrosion inhibition properties and give a ‘no-rust’ result against IP 135 B – Rust Preventing Characteristics of Steam Turbine Oil in the presence of synthetic salt water.

Oil Drain Periods:
For many years, 2000 hours has been generally accepted as an extended oil drain period for rotary vane and screw air compressor maintenance schedules and service requirements.

It is recognised that operating temperature has a fundamental effect upon the rate of oil degradation through oxidation.

With our Rotary Compressor Coolant incorporating the most up to date oil technology, 4000 hours oil change may now be accepted as the norm, even when operating at a continuous maximum discharge air temperature of 100 degree C.

Internal Cleanliness:

Coupled with the long life capability is the ability to maintain excellent internal surface cleanliness in service. This is particularly relevant to the function and operation of the separator/coalescer. Design varies according to the manufacturer; nominal filtration of ½ micron is typical for this application.

Blockage of these elements with what was thought to be polymerised products of oxidation has been endemic, in some cases after only 100/200 hours of operation.

In a test using Rotary Compressor Coolant, the separator element from a Compair-Broomwade Ltd trial machine was removed and inspected after 8400 hours of intermittent operation, simulating typical in-service conditions.The metal and fibreglass element were in ‘as new’ condition, and the dp (differential pressure) across the separator was recorded at a constant 2.5 psi over the whole evaluation.
The screw element from the trail assembly was also inspected and was found to be in excellent condition.


The Rotary Compressor Coolant is suitable for use in conjunction with all commonly used sealing materials.

Change-over Procedure:

Changeover is relatively straightforward:
1. The original charge should be fully drained and disposed of.
2. If the oil system has shown evidence of contamination or is otherwise less than satisfactory, a flushing charge may be appropriate.
3. Assuming item (2) not to apply, the system may be filled to the correct level and run in the normal way.
4. Assuming item (2) to be necessary, the flushing charge should be introduced and run up to normal working temperature for, say, 4 hours. It should then be fully drained, preferably at 50 degree C or above and then disposed of.
5. The working charge should then be introduced to the normal working level and the machine restarted.

Health And Safety:
The Rotary Compressor coolant is unlikely to present any significant health or safety hazard when properly used in the recommended application and good standards of industrial and personal hygiene are maintained.

See separate Safety Data Sheet.


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