Prima Compressor 4000
Case Study
The demands placed on screw air compressors are greater than ever. Often used in applications where breakdown or unscheduled maintenance is not an option, compressor reliability is essential.
Modern oil-flooded screw air compressors deliver increased performance more efficiently than their predecessors and are often more compact - with smaller lubricant sumps.
Air output temperatures of above 100C are increasingly common and demands from end-users to reduce maintenance costs and downtime has resulted in extended service intervals.
These requirements place increasing demands on compressor oils which have been met by the development of technically advanced lubricants based around modern synthetic base stocks and new high-performance additive chemistry.
Since the lubricant is injected as a fine mist and is constantly agitated, it presents a large surface area to hot moist compressed air. These conditions are very severe for any lubricant but are particularly conducive to the oxidation and carbonisation of mineral oil. As it oxidises, mineral oil increases in viscosity and can deposit carbon and gummy or varnish-like residues. These can adhere to and restrict the movement of compressor components reducing efficiency. In the worst case, this can lead to fires and explosions.
This is why Teklube TS has selected polyalphaolefins (PAOs) as the base fluid for the Prima Compressor range of fully synthetic screw air compressor lubricants.
Polyalphaolefins are a type of synthetic base fluid that can, in many ways, be thought of as an exceptionally pure form of mineral oil.
Advantages of PAOs over Mineral Oils:
Lower volatility
Higher flashpoint - safer
Lower pour point - better cold start performance
Higher VI (viscosity changes less with temperature)
No impurities
Inherently resistant to oxidation – less sludge and varnish
Somewhat better bulk thermal properties such as thermal conductivity
Lower coefficient of friction )
To support the performance levels of Prima Compressor 4000 a number of tests were conducted against two leading products sold as 4000-hour screw compressor lubricants:
Thermal Stability
We have previously noted the importance of the thermal and oxidative stability of modern compressor lubricants as a prerequisite to providing the characteristics discussed above throughout the lubricant’s life. Firstly, a simple demonstration of the inherent superior properties of the Prima Compressor 4000 compared to two well-regarded compressor lubricants from leading suppliers.
% Weight Loss after 7 days @1 50°C
Product Lifetime
Many compressor lubricant manufacturers quote results from the well-known Rotating Pressurised Vessel Oxidation Test (RPVOT) test. As specified by ASTM D2272.
A result of >1000 minutes is generally regarded as indicating a good quality lubricant.
Physical Characteristics
There are a number of physical properties of the lubricant which are particularly relevant when considering the formulation of compressor lubricants.
Viscosity and Pour Point
The majority of rotary screw air compressors require a kinematic viscosity of 46 CST at 40oC but it is also desirable for the lubricant to not become too thin at high temperatures or thicken up too much at lower temperatures. This property is expressed as the Viscosity Index or VI. We have seen how PAOs have inherently better low and high-temperature properties and this is reflected in the high VI of the Primascrew Compressor range. This effect is also observed in their inherently low very low pour points.
Flash Point
We have also seen that PAOs have lower volatility than mineral base oils of equivalent viscosity and this is reflected in the high flashpoints of the products with obvious safety benefits.
| Kinematic Viscosity at 40oC (ASTM D445) | 46 cSt |
| Viscosity Index (ASTM D2272) | 140 |
| Pour Point (ASTM D97) | <-40oc |
| Flash Point (COC) | >240oc |
| Meets or exceeds requirement | ISO 6743-3:2003 ISO-L-DAH ISO-L-DAG |