Gas Circulation Cooled Dry Roots Vacuum Pump

Two counter-rotating, precisely synchronized rotors move gas through the pump chamber without direct contact between rotor surfaces or housing walls. By keeping lubricating oils completely isolated in the gear and bearing housings, the pump maintains an ultra-clean pumping chamber.

Executive Summary & Key Advantages

100% Oil-Free Pumping Path: Zero risk of oil contamination in sensitive vacuum processes.
Continuous Heavy-Duty Operation: Integrated gas circulation cooling manages thermal loads and dynamic gas compression without overheating.
High Efficiency: Precision-profiled rotors minimize internal back-leakage, delivering maximum pumping speed per kilowatt.
Versatile Integration: Seamlessly integrates with rotary vane, dry screw, or liquid ring backing pumps via standardized ISO, CF, or ANSI flange interfaces.
Proven Quality Assurance: Built in ISO 9001-certified facilities with 100% dynamic balancing and dynamic factory performance testing prior to dispatch.

Technical Specifications

Parameter	Standard Specification Range	Custom / OEM Options
Pump Type	Gas Circulation Cooled Dry Roots Vacuum Pump	Special surface coatings (PTFE, Nickel)
Pumping Speed Range	150 m3/h to 4,500 m3/h (88 to 2,650 CFM)	Engineered larger capacities on request
Ultimate Total Pressure	/	Dependent on backing pump selection
Operating Pressure Range	Atmospheric Pressure	Optimized for continuous duty points
Cooling Method	Integrated Gas Circulation Cooling	External chiller / heat exchanger setup
Flange Connections	ISO-K / ISO-F (DN63 to DN250)	ANSI, CF, or customized interfaces
Allowable Gas Temp.	Inlet up to 80 deg C (176 deg F)	High-temperature inlet options available
Motor Power & Voltage	3.0 kW to 45 kW	380V / 415V / 460V, 50/60Hz, IE3/IE4
Explosion Protection	Standard non-sparking design	ATEX / IECEx certified models available
Leakage Rate	/	High-integrity helium leak testing
Noise Level	72 dB(A) to 82 dB(A) at 1 meter	Optional acoustic attenuation enclosures

Key Selection Parameters

Pumping Speed & System Sizing: Capacity calculations must account for chamber volume, target pump-down time, process gas throughput, dynamic peak loads, and outgassing rates.
Operating Pressure & Backing Pump Matching: A dry Roots booster operates within defined differential pressure limits. To achieve deeper vacuum levels:
System Configuration: Process Chamber - Roots Vacuum Pump -Backing Pump - Exhaust
Matching Ratio: Typically 1:4 to 1:10 depending on working pressure and gas density.
Gas Composition & Process Compatibility: Process gas chemistry dictates material selection. Corrosive vapors require protective coatings, dust requires inlet filters, and condensable vapors require gas purge systems.

Field Application Scenarios

Industrial Vacuum Drying & Solvent Recovery: Standard oil-sealed pumps suffer from lubricant degradation when exposed to moisture and solvent vapors. The dry chamber design eliminates oil emulsification, extending system uptime and reducing maintenance costs by up to 40%.
Thin-Film Vacuum Coating (PVD/CVD): Oil backstreaming causes film defects and adhesion failures. This pump provides a 100% hydrocarbon-free path, ensuring consistent coating quality and stable continuous operation under heavy process gas loads.
Chemical & Pharmaceutical Processing: Handling hazardous or aggressive vapor mixtures requires leak-tight containment. Magnetically coupled drives and ATEX configurations prevent process gas leakage into the workspace.

Application Limitations

To prevent unexpected downtime or equipment damage, technical confirmation is required if your application involves:

High concentrations of strong acid vapors (HCl, HF) or strong alkaline gases.
Abrasive dust or hard particulates entering the suction port without pre-filtration.
Continuous operation exceeding maximum allowable differential pressure limits.

Quality Assurance & Documentation

Quality Control Standards
Rotor Precision Machining: Manufactured on 5-axis CNC centers with 100% dynamic balancing (ISO 1940 Grade G2.5).
Housing Alignment: CMM inspection ensures micron-level clearances between rotors and housing walls.
Factory Acceptance Testing (FAT): Vibration analysis, noise measurement, temperature-rise verification, and continuous running tests prior to shipment.
Documentation Package Provided
Factory Test Report (Vacuum performance, Vibration, Leak Rate)
ISO 9001 / CE Conformity Declarations
Operation & Maintenance Manual with Spare Parts List
2D Installation Drawings (DWG/DXF) & 3D STEP Models

Technical RFQ Checklist

RFQ Parameter	Details Required
Target Pressure	Required operating pressure (mbar / Torr) & ultimate vacuum
Process Gas Details	Gas composition, corrosiveness, and moisture/vapor content
Gas Flow Load	Continuous flow rate (kg/h or SLLM) and peak load expectations
Gas Inlet Temp.	Normal and maximum gas inlet temperature (deg C)
Chamber Volume	Chamber volume (m3) and target evacuation time
Backing Pump Info	Existing backing pump model, or state if full skid is needed
Power Supply	Local voltage, frequency, phase, and explosion-proof requirements

FAQ

Q: Why choose a gas circulation cooled dry Roots pump over a standard Roots pump?

A: Standard Roots vacuum pumps rely on external cooling and backing pump throughput to dissipate heat, limiting their allowable differential pressure. Gas circulation cooling actively manages internal temperatures, allowing the pump to operate reliably under higher pressure differentials and heavy dynamic gas loads without rotor seizure.

Q: Does this dry Roots pump require a backing pump to operate?

A: Yes. A Roots pump is a vacuum booster that requires a suitable backing pump (such as a dry screw pump, rotary vane pump, or liquid ring pump) to discharge gas against atmospheric pressure and achieve optimum ultimate vacuum levels.

Q: How does the pump maintain an oil-free environment if gears and bearings require lubrication?

A: The pumping chamber is completely isolated from the gearboxes and bearing housings using advanced mechanical shaft seals and labyrinths.

Q: Can this pump handle condensable vapors or light particulate loads?

A: Yes, provided the proper configuration is selected. For condensable vapors, gas ballast or purge options keep vapors in the gas phase.

Q: What technical documentation is included for OEM integration?

A: We provide complete CAD support, including 2D dimensional drawings (DWG/DXF), 3D STEP files, motor data sheets, pumping speed curves, and factory acceptance test (FAT) reports to simplify integration into OEM equipment.

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