QISHANR QSL-612 Vacuum Pump Oil 1L - High-Performance Industrial Vacuum Pump Lubricant

Company Introduction

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.

QSL-612 Vacuum Pump Oil — Quick Summary

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.

What Is QSL-612 Vacuum Pump Oil?

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.

Key Benefits

• Excellent Anti-Oxidation Stability: Resists thermal and oxidative degradation during continuous high-temperature operation, preventing the formation of sludge, varnish, and acidic byproducts that can corrode pump internals and clog oil passages. Extended oxidation stability means longer oil life and fewer unscheduled maintenance interventions.
• Superior Anti-Rust & Corrosion Protection: Contains effective rust inhibitors that form a protective film on ferrous metal surfaces, safeguarding pump rotors, vanes, bearings, and housing walls against moisture-induced corrosion. This is especially critical in applications where humid ambient air or process gases introduce water vapor into the pump chamber.
• Low Volatility & High Flash Point: The deeply refined base oil minimizes volatile light-end fractions that would otherwise vaporize under vacuum, ensuring the pump can achieve and maintain its rated ultimate pressure without oil backstreaming. The high flash point provides a wide margin of safety during elevated-temperature operation and reduces the risk of oil mist ignition in the exhaust.
• Outstanding Demulsibility & Air Release: Rapidly separates from water contamination through fast demulsification, preventing the formation of stable oil-water emulsions that degrade lubrication and sealing performance. Superior air release properties minimize foaming and entrained air bubbles, which can cause cavitation damage and erratic vacuum gauge readings during pump operation.
• Stable Lubrication Under High Vacuum: Maintains adequate film strength and viscosity under the extreme pressure differentials and elevated operating temperatures characteristic of deep vacuum conditions, where ordinary lubricants thin out, lose sealing capability, or suffer accelerated thermal breakdown.

Applications & Compatible Vacuum Pump Types

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:

• HVAC/R system evacuation and refrigerant charging (air conditioning, refrigeration, heat pump installation and servicing)
• Vacuum furnaces for heat treatment, brazing, and sintering in metallurgical and aerospace industries
• Freeze drying (lyophilization) equipment for pharmaceutical, biotechnology, and food processing applications
• Vacuum packaging machinery for food, electronics, and medical device industries
• Electron microscopy and mass spectrometry where stable high vacuum is critical for instrument performance
• Vacuum coating and thin-film deposition systems (PVD, CVD) in optics and semiconductor fabrication
• Vacuum impregnation of electrical windings, castings, and porous materials
• Central laboratory vacuum systems serving multiple workstations

Why Vacuum Pump Oil Matters: Oxidation, Moisture, and Pump Longevity

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:

Oxidative Degradation

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.

Moisture Contamination

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.

Volatility and Ultimate Vacuum Limitation

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.

The Economic Case for Quality Vacuum Pump Oil

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.

Oil Change & Maintenance Guide

Proper oil change practices are the single most effective action for extending vacuum pump service life. Follow these guidelines when using QISHANR QSL-612:

When to Change the Oil

• Visual Inspection: Change the oil when it darkens significantly from its original light amber color to dark brown or black. A color comparison chart (available from most vacuum pump manufacturers) provides an objective reference. Oil that appears milky or cloudy indicates water emulsification and requires immediate change.
• Operating Hours: For rotary vane pumps in clean, dry-gas applications, change oil every 500 to 1,000 operating hours. For pumps handling humid air, solvent vapors, or aggressive process gases, reduce the interval to 250 to 500 hours or less depending on gas load severity.
• First Oil Change: After initial fill or after a major overhaul, change the oil after the first 100 operating hours to remove any wear-in particles and assembly residues from the pump internals.
• Ultimate Pressure Degradation: If the pump no longer achieves its rated ultimate vacuum pressure (measured with a calibrated vacuum gauge at the inlet), an oil change should be the first diagnostic step before investigating mechanical causes.
• After Contamination Events: Change the oil immediately after any known contamination event — such as pumping significant quantities of water, solvents, or particulate-laden gas — regardless of how recently the oil was changed.

Best Practices for Oil Changes

1. Change Oil While Warm: Run the pump for 10-15 minutes to warm the oil and suspend settled contaminants before draining. Warm oil flows more readily and carries out more contaminants than cold oil. Allow the pump to cool slightly before handling to avoid burn risk.
2. Drain Completely: Open the drain plug and allow the oil to drain fully. Tilt the pump slightly if needed to ensure complete drainage from the oil sump. For pumps with an oil filter, replace the filter element during every oil change.
3. Flush if Heavily Contaminated: If the drained oil is heavily contaminated (very dark, containing visible sludge or water), perform a flushing fill with a small quantity of fresh QSL-612. Run the pump for 5-10 minutes with the gas ballast valve open (if equipped) to circulate the flushing oil, then drain again before filling with the service charge.
4. Refill to Correct Level: Fill with fresh QSL-612 to the oil sight glass center mark. Overfilling can cause oil carryover into the exhaust and excessive power consumption. Underfilling risks inadequate lubrication and loss of vacuum sealing. Check the level again after a brief run to account for oil distribution into the pump mechanism.
5. Use the Gas Ballast: If your pump is equipped with a gas ballast valve (standard on most two-stage rotary vane pumps), operate it periodically during normal use. The gas ballast introduces a small amount of atmospheric air into the compression stage, which raises the partial pressure of water vapor and allows it to be expelled before condensation occurs. This significantly extends oil life when pumping humid gases. Run with the gas ballast open for 20-30 minutes after each humid pumping session to purge accumulated moisture from the oil.

Oil Storage Recommendations

• Store QSL-612 containers in a clean, dry, indoor environment away from direct sunlight and temperature extremes.
• Keep containers tightly sealed when not in use to prevent moisture absorption and particulate contamination from ambient air. Vacuum pump oil is hygroscopic over time; prolonged exposure to humid air can introduce dissolved water.
• Use opened containers within 12 months. For infrequent users, consider purchasing in smaller container sizes to minimize storage degradation.
• Do not store oil near chemicals, solvents, or strong oxidizing agents that could permeate containers or react with the oil.
• Label opened containers with the date of first opening for tracking purposes.

Why Choose QISHANR QSL-612?

• Purpose-Formulated for Vacuum Pumps: Unlike general-purpose industrial oils repurposed for vacuum pump use, QSL-612 is specifically engineered for the unique demands of vacuum pump lubrication — low vapor pressure, rapid water separation, oxidative stability at sustained elevated temperatures, and compatibility with the materials and operating conditions found in oil-sealed vacuum pumps. The formulation was developed with input from vacuum equipment service technicians to address the most common field failure modes.
• Proven Quality & Certification: SGS certified, manufactured under an ISO 9001 quality management system. Each production batch is tested for kinematic viscosity, flash point, pour point, demulsibility, oxidation stability (RBOT), and corrosion protection (copper strip test) to ensure consistent performance before release.
• Technical Support & Cross-Referencing: Our engineering team provides guidance on oil selection for specific pump models, oil change interval optimization based on your operating conditions, and cross-referencing with OEM-branded vacuum pump oils from major pump manufacturers. Contact us with your pump make and model for a compatibility confirmation.
• Flexible Supply & Customization: Standard packaging includes 1L, 4L, 5L, 20L, and 200L options. OEM/ODM services available including private labeling, custom packaging design, and tailored formulations for unique operating environments. Complete export documentation (MSDS, CO, CE) provided for international shipments. Factory-direct pricing with competitive freight options including sea, land, air, and express delivery.

Frequently Asked Questions

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.

Key Takeaways

• What it is. QISHANR QSL-612 is a mineral-based vacuum pump oil supplied in a 1 L pack by Guangzhou Qishanr Technologies Co., Ltd., for industrial mechanical vacuum pumps.
• Where it is used. Rotary vane, rotary piston and screw vacuum pumps in HVAC evacuation, vacuum furnaces, freeze drying, vacuum packaging, electron microscopy and semiconductor manufacturing.
• Base oil. Highly refined mineral base oils with a balanced anti-oxidation and anti-rust additive package.
• Performance focus. Low volatility and a high flash point for safe operation at elevated temperatures, plus demulsibility and air-release properties that resist foaming and separate water quickly.
• What it protects. A stable lubrication film under high vacuum, where ordinary lubricants break down through extreme pressure differentials and outgassing.
• Manufacturer. Guangzhou Qishanr Technologies Co., Ltd. — we blend this grade at our own plant in Foshan, Guangdong, China.
• Origin. Supplied from our own manufacture in Foshan, China. State any origin requirement on the enquiry.
• Documents and terms. Technical data sheet, safety data sheet and certificate of analysis are available, and CE, CO and MSDS cover export. Pack size, price term, payment term and lead time are confirmed per order.

Standards and Sources Behind the Data on This Page

The viscosity class system used across our vacuum pump oil range follows ISO 3448, and the pump-performance terminology follows ISO 21360-1. The application and maintenance notes on this page are our own service guidance for QISHANR QSL-612.

• ISO 3448:1992 Industrial liquid lubricants — ISO viscosity classification (International Organization for Standardization)
• ISO 21360-1:2020 Vacuum technology — Standard methods for measuring vacuum-pump performance — Part 1: General description