Guangzhou Qishanr Technologies Co., Ltd. is a professional manufacturer and supplier focusing on R&D, production and sales of high-performance industrial lubricants, base oils and functional additives. With over 10 years of production experience, our self-owned brand QISHANR features excellent compatibility and interchangeability with mainstream equipment requirements. Our products are SGS certified and comply with international industry standards, widely used in refrigeration, air conditioning, vacuum technology, and industrial machinery. We provide professional model selection technical support and flexible OEM / ODM customization services, delivering reliable and cost-effective lubrication solutions for global customers.
QISHANR QSL-612 is a high-performance mineral-based vacuum pump oil specifically designed for industrial mechanical vacuum pumps. It combines excellent anti-oxidation stability, effective rust and corrosion protection, low vapor pressure, and rapid water separation capability to deliver reliable lubrication under the demanding conditions of high vacuum operation, extending pump life and maintaining consistent ultimate vacuum performance.
Vacuum pump oil serves a fundamentally different role from general-purpose industrial lubricants. While a standard hydraulic or gear oil primarily focuses on reducing friction and wear, a vacuum pump oil must simultaneously perform multiple critical functions: it seals the microscopic clearances between rotors, vanes, and housing walls to maintain vacuum integrity; it dissipates the heat generated by gas compression within the pump chamber; it protects internal components from corrosion caused by condensed moisture and aggressive process gases; and it must do all of this without itself becoming a source of contamination through outgassing or vaporization under deep vacuum.
QISHANR QSL-612 is formulated specifically for these demands. Its highly-refined mineral base oil undergoes a deep distillation and hydrotreatment process to remove volatile light fractions that would otherwise vaporize under vacuum and limit the pump's ultimate pressure. The precisely balanced additive system provides rust inhibition to protect ferrous pump components from moisture attack, oxidation resistance to prevent sludge and varnish formation during prolonged high-temperature operation, and demulsifying agents that promote rapid separation of emulsified water — a common contaminant in vacuum pump oil caused by condensation of atmospheric humidity drawn into the pump. The result is a vacuum pump lubricant that maintains its sealing and lubricating properties across extended service intervals, even in demanding industrial environments.
QISHANR QSL-612 is formulated for all major types of oil-sealed mechanical vacuum pumps used in industrial, laboratory, and commercial applications:
Rotary Vane Vacuum Pumps: The most common type of mechanical vacuum pump, used extensively in HVAC/R evacuation, vacuum packaging, vacuum forming, medical suction systems, and laboratory applications. QSL-612 provides the precise viscosity required for effective vane-to-housing sealing while resisting the thermal breakdown caused by gas compression heating during extended evacuation cycles.
Rotary Piston Vacuum Pumps: Used in heavier-duty industrial vacuum applications including vacuum furnaces, vacuum impregnation, large-scale freeze drying, and central vacuum systems. These larger pumps operate at higher oil volumes and temperatures; QSL-612's anti-oxidation stability and high flash point make it well-suited for the thermal demands of continuous-duty rotary piston pump operation.
Screw Vacuum Pumps (Oil-Lubricated): Employed in clean industrial processes such as semiconductor manufacturing, coating deposition, and pharmaceutical freeze drying where oil-free compression is combined with oil-lubricated bearings and timing gears. QSL-612 provides reliable lubrication for the bearing and gear systems while resisting contamination from trace process gases.
Typical Application Scenarios:
Understanding why vacuum pump oil quality directly determines pump performance and service life is essential for anyone responsible for vacuum equipment maintenance. Three degradation mechanisms are primarily responsible for vacuum pump oil failure:
During operation, a vacuum pump compresses gas from the inlet (near vacuum) to atmospheric pressure at the exhaust. This compression generates significant heat — oil sump temperatures of 70°C to 95°C are common in continuous-duty rotary vane pumps, and hot spots at the compression zone can exceed 120°C. At these temperatures, the oil reacts with oxygen present in the pumped gas stream, initiating a chain reaction of hydrocarbon oxidation. The process accelerates autocatalytically as oxidation byproducts (organic acids, aldehydes, ketones) further catalyze additional oxidation. The visible result is oil darkening from amber to deep brown or black, accompanied by viscosity increase and sludge formation. The sludge deposits on internal surfaces, restricts oil flow, clogs filters, and impairs heat transfer — all of which push operating temperatures still higher in a destructive feedback loop. QSL-612's oxidation inhibitor system interrupts this chain reaction at the molecular level, significantly extending the oil's useful life and protecting pump internals from oxidative deposits.
Atmospheric air contains water vapor. When this air is drawn into a vacuum pump, the water vapor condenses as it is compressed, introducing liquid water into the oil sump. This is particularly acute when evacuating systems that have been open to ambient air, such as during HVAC installation or after maintenance procedures. Water contamination in vacuum pump oil causes multiple problems: it reduces oil viscosity and film strength, promotes rust and corrosion on ferrous pump components, and forms emulsions that degrade sealing performance and increase the pump's ultimate pressure. In severe cases, the water-oil emulsion can fill the pump housing and cause hydraulic lock on startup. QSL-612's demulsibility additives cause water to coalesce rapidly into separate droplets that settle to the bottom of the oil reservoir, where they can be drained off through the oil drain plug rather than remaining suspended in the oil to cause ongoing damage.
Every liquid has a vapor pressure — the tendency of its molecules to escape from the liquid phase into the gas phase. For a vacuum pump to achieve a deep vacuum, the vapor pressure of its sealing oil must be lower than the target ultimate pressure. Oils containing volatile light hydrocarbon fractions will continuously outgas under vacuum, generating a background vapor pressure that the pump cannot overcome, effectively setting a floor on achievable vacuum. QSL-612's deeply refined base oil with minimal volatile content ensures that the oil itself does not become the limiting factor in the pump's ultimate vacuum performance.
A major overhaul of a contaminated or worn industrial vacuum pump — involving rotor re-machining, vane replacement, bearing replacement, and housing reconditioning — can cost several thousand dollars and take the pump out of service for weeks. By comparison, using a high-quality vacuum pump oil like QSL-612 with proper change intervals costs a modest incremental amount per oil change while dramatically reducing the frequency of major overhauls. The total cost of ownership calculation strongly favors premium lubricant selection, particularly for pumps in continuous or revenue-critical service.
Proper oil change practices are the single most effective action for extending vacuum pump service life. Follow these guidelines when using QISHANR QSL-612:
Q: Can I use regular motor oil or hydraulic oil in my vacuum pump?
A: This is not recommended and can cause significant pump damage. Standard motor oils and hydraulic oils have much higher vapor pressures than vacuum pump oils, meaning they will outgas under vacuum and prevent the pump from achieving its rated ultimate pressure. They also lack the demulsibility additives needed to separate water contamination, and their anti-oxidation packages are formulated for different temperature ranges and operating conditions. Using non-vacuum-grade oil will result in poor vacuum performance, accelerated oil degradation, and potential pump damage. Always use a purpose-formulated vacuum pump oil like QISHANR QSL-612.
Q: How often should I change the vacuum pump oil?
A: Oil change frequency depends on the application and operating conditions. For clean, dry-gas applications, change every 500 to 1,000 operating hours. For humid or contaminated gas applications, change every 250 to 500 hours or when the oil shows visible darkening or cloudiness. As a practical rule, change the oil when its color has darkened to approximately twice the darkness of fresh oil, or sooner if the pump's ultimate vacuum pressure begins to degrade. The first oil change after initial pump fill or overhaul should be performed after 100 operating hours to remove wear-in debris.
Q: What causes vacuum pump oil to turn milky or cloudy?
A: Milky or cloudy oil is a clear sign of water emulsification. This occurs when water vapor from the pumped gas stream condenses during compression and mixes with the oil to form a stable emulsion. It is most common when evacuating systems that have been open to humid ambient air, such as during HVAC installation or after equipment maintenance. If your oil appears milky, change it immediately — the emulsified water drastically reduces lubrication quality, promotes rust formation, and significantly increases the pump's ultimate vacuum pressure. To prevent recurrence, use the pump's gas ballast valve (if equipped) for 20-30 minutes after pumping humid gases, which helps expel water vapor before it can condense into the oil.
Q: Can QISHANR QSL-612 be used in two-stage (high vacuum) rotary vane pumps?
A: Yes. QSL-612 is specifically formulated for use in both single-stage and two-stage rotary vane vacuum pumps. Two-stage pumps achieve deeper ultimate vacuum (typically below 10^-3 mbar) than single-stage designs, placing greater demands on oil vapor pressure. QSL-612's deeply refined base oil with minimal volatile content ensures that the oil vapor pressure does not become the limiting factor in the pump's ultimate vacuum capability. The oil's demulsibility and anti-oxidation properties are equally important in two-stage pumps, which operate at higher compression ratios and consequently higher internal temperatures.
Q: What is the gas ballast and when should I use it?
A: The gas ballast is a valve found on most quality rotary vane vacuum pumps that admits a controlled amount of atmospheric air (or dry nitrogen) into the compression stage of the pump. This raises the partial pressure at which water vapor and other condensable vapors are discharged, allowing them to be expelled as vapor before they reach condensation pressure — effectively purging moisture from the oil. Use the gas ballast when pumping gases known to contain water vapor or solvent vapors. After completing such pumping operations, run the pump with the gas ballast open for an additional 20-30 minutes (with the inlet closed or blanked off) to fully purge accumulated moisture from the oil. Note that operating with the gas ballast open slightly increases the pump's ultimate pressure and operating noise, which is normal behavior.
Technical content reviewed by the QISHANR Lubricants Engineering Team. Product specifications and recommendations are based on laboratory testing and field application data. For application-specific guidance or to discuss your vacuum pump lubrication requirements, contact our technical support team.
