Rotary screw compressors

Rotary screw compressors

50 HP to 250 HP

Rotary Screw Gas Compressors SSY

LeROI Rotary Screw Gas Compressors incorporate design features that meet the demands for efficient, flexible, durable operation placed on them by the Natural Gas Industry.

Design Features

  • O-Ring Flange Seals
  • Large Rotors and Bearings for Low Speed Operation
  • Cylindrical Roller Inlet Bearings
  • Tapered Roller Discharge Bearings
  • Automatic Turn Valve Capacity Control
  • Stop-Limits for Fully Opened and Fully Closed Turn Valve Positions
  • Turn Valve Indicator Standard on All Gas Ends
  • 3 Axis Vibration Pick-up Points
  • Available Frame-Mounted Oil Pump
  • Available Horizontal Inlet Valve
  • Field-Changeable Vi, With Four Settings From 2.8 to 4.6

Exclusive LeROI Features

All LeROI Rotary Screw Gas Compressors contain a unique combination of outstanding features

  • Exclusive KYPHO rotor profile returns greater efficiency over its operating range and delivers a 3% to 5% operating efficiency advantage over standard rotor designs. Its asymmetrical rotor shape inherently provides a tighter seal between the grooves of the rotors to reduce slippage, eliminate vibration, and increase efficiency.
  • Rotors, up to 41% larger in diameter than other gas compressor brands, allow our rotor operating speeds to be among the lowest in the industry. Low speeds extend compressor life, reduce compression heat and contribute to a total cost of ownership.
  • Long-life bearings mean longer service. All LeROI gas compressors are designed with large, cylindrical roller bearings at the inlet and time-proven tapered roller bearings at the discharge. LeROI uses bearings as much as 170% larger than competitive models.
  • New “Quick Change Vi” feature (available on SSU & SSY models) allows the user to choose from four Vi ratios at which to operate, using a quick and easy method of changing the arrangement of spacers and plugs at the discharge end. The right Vi for your application means maximum efficiency, meaning no additional parts to buy or keep in stock.

Rotary Screw Gas Compressors HG12

LeROI Rotary Screw Gas Compressors are very costeffective for handling high volumes of gas in field gathering, vapor recovery, and other applications. The HG12 and HGF. Series are suitable for applications to 125 BHP and 350 PSIG discharge pressure. Low maintenance and high reliability are inherent with rotary screws because they have few moving parts. There are no valves, rings or packing to wear out or cause loss of efficiency.

Smooth operation results from no unbalanced forces and no pressure pulsation. No foundation is required and there are no piping vibrations from pressure pulsation. Natural gas engine or electric motor drives are equally acceptable with rotary screws. LeROI Rotary Screw Gas Compressors are available in various models covering a flow range of 20 to 15,000 MSCFD and horsepower from 10 to 900.


The HG12000 can be belt driven or directly coupled to electric motors for maximum flexibility at minimum cost. The compressor shaft bearings can absorb the belt side
load without additional pillow block bearing supports up to 50 HP. Models HG12XXX and HGF12000 are suitable for direct coupling to engines and electric motors.

Single-Stage operation from 20 PSIG to 350 PSIG maximum is possible with the HG12 and HGF Series oil-flooded compressors. Compressor packages are therefore simple, reliable and in expensive. The gas differential pressure provides oil circulation for proper lubrication at differential pressures over 70 PSI. Optional oil pumps are available for applications with less than 70 PSI differential pressure.

Discharge porting can be selected to match the internal compression to the application requirement for maximum compression efficiency. All iron or steel construction with no copper or copper alloys makes these compressors compatible with natural gas, sweet or sour.


  • Brake Horsepower 125 Max.
  • Flow Range (MSCFD) 1,400 Max.
  • Inlet Pressure 20″ Hg Vac. Min.* 50 PSIG Max.
  • Discharge Pressure 20*–350 PSIG (MAWP)
  • Input Speed Range
    – HG12 Non-Geared 2,250/Min. 6,000/Max. RPM
    – HGF12 Non-Geared 1,500/Min. 4,000/Max. RPM
    – HG12 Geared 750/Min. 3,600/Max. RPM

    * Consult Factory for use with lower vacuum inlet or discharge pressures.

Technical Specifications

  • Model HG12000, HGF12000 Non-Geared & HG12XXX Geared
  • Rotor Diameter 127.5 mm (5.02 inches)
  • Rotor L/D 1.65
  • Rotor Description
    – Twin Screw SRM Profile with Sealing Strips, 4 Lobe Male, 6 Lobe Female
  • Shaft Seal(s) – Mechanical*
  • Drive System
    – HG12000 is suitable for direct coupling to electric motor or belt drive – oversized input shaft bearings for belt side load up to 50 HP. Rotation – Facing Shaft – CCW. Drive Shaft 1⅝” Dia. with ⅜” Square Key.
    – HGF12000 Female Rotor Drive, Non-Geared, Drive Shaft 1⅜” Dia. with ⅜” Square Key.
    – HG12XXX uses internal helical speed increasing gears (AGMA 11). Gear ratios of 1.2-3.1 are available. Drive Shaft 1⅝” Dia. with ⅜” Square Key. The HGF12000 Non-Geared and HG12XXX Geared are CW rotation suitable for direct coupling to engines or electric motors.
  • Materials
    – Rotors – Ductile Iron 65-45-12
    -Castings – Cast Iron G3000
    – Bearings – Roller bearings on the inlet end and tapered roller bearings on the discharge end – alloy steel races, rolling elements and cages.
  • Weight
    – HG12000 & HGF12000 Non-Geared – 330 lbs
    – HG12XXX Geared – 410 lbs


  • Gas Gathering
  • Fuel Gas Boosting
  • Inert Gas Boosting
  • Biogas
  • LNG Boil-Off Gas
  • Well Head Gas Compression
  • Vapor Recovery
  • Landfill Gas
  • Plunger Lift
  • Rotary Screw Gas Compressors - Gas Bare Series
  • Rotary Screw Gas Compressors - HG12 & HGF12 Series
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