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Blackmer® is the leading global provider of innovative, high-quality sliding vane, centrifugal, screw and regenerative turbine pump, and reciprocating gas compressor technologies for the safe transfer of liquids and gases.

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Sliding Vane Pumps

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Providing Innovative Product-Transfer Solutions for a Variety of Markets and Applications

Blackmer provides innovative product transfer solutions for many markets and applications, including in the chemical process, energy, transport, military & marine; general industrial, and oil & gas industries.

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General Industrial

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Blackmer HD942, LB940 Series Reciprocating Gas Compressors Blackmer LB942 Series Reciprocating Gas Compressor

LB940 Series Reciprocating Gas Compressors LB942, LB943

Equipped with two double-acting cylinders, the LB940 Series compressors, featuring the LB942 and LB943 models, provide high volume fluid transfer and gas compression of propane, butane, and anhydrous ammonia for large applications ranging from barges, ships and railcars. They offer high flow rates of 125.2 CFM at 825 rpm. Compared to competitors and other LB Series compressors, the LB940 Series are equipped with thicker and more robust wear parts – piston rings, wrist pins, needle bearings, and high-efficiency valves that will keep the LB940 Series compressors operating longer than the competition between maintenance cycles. Equipped with an array of features such as a ductile iron head and cylinders, steel pistons and self-adjusting piston rod seals, LB compressors provide maximum performance, energy efficiency, quiet operation, low maintenance cost and reliability under the most severe service conditions.

Performance and Specifications

Units LB942, LB943
No. of Cylinders 2 Double Acting
Bore x Stroke, in. (mm) 4.625 x 4.0 (117 x 102)
MAWP, psia (kPa) 350 (2,413)
Speed, rpm 350 - 825
Piston Displacement
@ 350 rpm, CFM (m³/hr) 52.46 (89.1)
@ 825 rpm, CFM (m³/hr) 125.2 (212)
Max. Power, BHP (kW) 50 (37)
Weight, lb. (kg) ~905 (~410)
Inlet/Outlet Connections 2" 300# ANSI

Features and Benefits

  • High efficiency valves move more gas volume
  • O-ring seals for head and cylinder to ensure positive sealing
  • Ductile iron construction for greater resistance to both thermal and mechanical shock
  • Wear-resistant crosshead assemblies
  • Heavy-duty crankshafts
  • Pressure assisted piston rings for positive seating
  • Self-adjusting piston rod seals
  • Double and triple piston rod seals with distance piece chambers available


  • Liquid transfer
  • Vapor recovery
  • Liquefied gas compression
Interactive LPG Application Map*

*NOTE: This application was originally built for interactive touch screens with a resolution of 1920x1080 using Google Chrome in full-screen mode.

Visit the Compressor Solutions page for more information about the LB Series Reciprocating Gas Compressors.
Learn more about Blackmer Reciprocating Compressors with our interactive tool.


Options Available Literature  Details
Crankcase Oil Heater CB322 Used to maintain adequate oil temperature in cold to severe climates 
Distance Piece Options CB037 Section of gas compressor between crankcase and compressor cylinder that isolates the two areas, providing oil-free operation for cylinder 
Pressure Gauges CB105 Various pressure gauges available
Extended Crankshaft   Extended crankshaft available for direct drive mounting
Oversized Flywheels   Available for various drive options

Ancillary Equipment

Equipment Available Literature  Details
4-Way Valves CB046 For piping, in aiding for easy transition from liquid transfer to vapor recovery - comes with handle and flow indicator
Electrical Schematic CB276  Overview of a generalized wiring schematic for typical installations
Float Switch Information CB145 Activates alarms and/or shut-down equipment when a liquid rises or falls past the switch
Liquid Traps CB212 Trap installed in the suction line to stop liquid from entering the compressor
Liquid Traps, ASME Code CB218  ASME coded trap installed in the suction line to stop liquid from entering the compressor
Low Oil Pressure Switches  CB020  Sends signal when the compressor's crankcase oil pressure falls 
Mounting Arrangements  CB111  A variety of mounting arrangements available for compressors 
Strainer CB172  Features a 30-mesh stainless steel screen 
Belt Guards 
Available in either aluminum or stainless steel 
Pressure Switches    Activates alarms and/or shutdown equipment for suction, discharge, differential, and/or oil pressure 
Temperature Switches    Activates alarms and/or shutdown equipment for discharge and/or oil temperature 
Temperature Gauges    Visual confirmation of temperature - typically on the suction and discharge process gas location 
Thermowells    Protects temperature monitoring devices from harsh process gas conditions 
Control Panels and Starters    Junction box and full turn-key functionality available in required classifications 
NPT or Welded Piping Systems    Threaded or welded steel piping systems 
Pressure Gauges  CB105  Visual confirmation of pressure - typically on the suction, discharge, and oil locations 
Receivers    Often times used as a holding vessel for pressure control on the suction or discharge 
Relief Valves    Overpressure safety devices required on the compressor discharge and any associated ASME code vessels 
Shutoff Valves    Available in either manual or powered 
Aftercoolers    Available in either air or water cooled 
Motor or engine drives    Available in various classifications and fuel types 
Repair tool kits  CB110  List of part numbers for special tools and tool kits used on compressors
Unloader Solenoid Valve CB315 3-way solenoid for suction valve unloader control available on LB942/943 models

Maintenance Tools

Maintenance Tools – LB942B, LB943B Part Number
Packing Installation Tool 790540
Spanner Wrench, 1/4" Adjustable 790316
Wrench for Valve Holdown Screw 790535
Compressor Tool Kit N/A
Valve Tool 798016
Piston Tools N/A
Packing Ring Tool 798017


View the Blackmer Compressor maintenance videos here.

Installation Operation Manuals (IOMs)

Materials of Construction

LB160 Series, LB360 Series, LB600 Series, LB940 Series


LB160 Series, LB360 Series, LB600 Series, LB940 Series