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Blackmer NP2 Steam Jackets 600 Blackmer NPH4F Pump 600 Blackmer NP2 with Cartridge Seal 600

NP Series Sliding Vane Pumps Equipped with Self-Lubricating Internal Sleeve Bearings for Maintenance-Free Performance

Specifically designed to offer maximum versatility for handling a wide variety of clean non-corrosive liquids, NP Series Sliding Vane Pumps, which are part of the Iron Line, are a general purpose positive displacement pump ideal for applications where high temperature, high pressure, high viscosity and/or shaft sealing requirements dictate a sleeve bearing pump are used. The key to the NP Series' versatility is the Blackmer® unique sliding vane rotor design that provides sustained, high level performance over a wide viscosity range. Slow operating speeds and non-pulsating flow minimizes shear and agitation of the fluid.

The unique head and bearing design of the NP Series pumps is conducive to a long bearing life - this design allows a small quantity of fluid to flow from the discharge side of the pump to the bearings. The small, continuous flow of fluid over the bearing surfaces provides a hydrodynamic film, minimizing temperature rise. These pumps are self-priming and dry run capable due to self-adjusting vanes. The NP pumps can run dry for short periods of time, ideal for priming and line stripping. Additionally, high volumetric efficiency and symmetrical bearing support mean the NP Series pumps require less horsepower than other PD pumps, which increases efficiency and cost savings to operate the pumps.

Blackmer fully Integrated Unit Assemblies are the pre-engineered and pre-designed drop-in pumping solution. These unit assemblies, include motor, gearbox, baseplate, coupling safety covers, and a NP Stainless Steel Sliding Vane Pump. No alignment required with these pre-configured fully Integrated Unit Assemblies as they are ready for immediate drop-in installation.

Features and Benefits

  • Ductile-iron construction with metallized carbon sleeve bearings and non-metallic vanes for longer life
  • Optional commercial mechanical seal with stainless steel, carbon, and PTFE construction
  • Shaft stuffing box accommodates most standard aftermarket mechanical seal configurations
  • Jacketed pump head option for high temperature operation
  • Pump design and operation minimizes shear and agitation
  • Adjustable relief valve protects pump against excessive pressures
  • Advantages of sliding vane technology:
    • Unique sliding-vane pump design self-adjusts for wear to maintain flow rates
    • Excellent self-priming and dry-run capabilities
    • Sliding vane design provides sustained performance and trouble-free operation
    • Easy maintenance: vanes can be easily replaced without removing the pump from the piping system
    • High suction lift and line-stripping capabilities
    • Low maintenance and low life-cycle costs


  • Refiled fuels
  • Greases
  • Solvents
  • Chocolate
  • Syrups
  • Molasses
  • Edible oils
  • Black liquor
  • Sodium silicate
  • Tallow
  • Wax
  • Glues
  • Adhesives
  • Creosote
  • Asphalt
  • Aqueous Film Forming Foam (AFFF)

Performance and Specifications

  • NP1.5
  • NP2
  • NP(H)2
  • NP2.5
  • NP(H)2.5
  • NP3
  • NP(H)3
  • NP4
  • NP(H)4
  • 1.5": 2 - 47 gpm (8 - 178 L/min)
  • 2": 10 - 77 gpm (38 - 291 L/min)
  • 2.5": 20 - 136 gpm (76 - 515 L/min)
  • 3": 60 - 276 gpm (227 - 1,045 L/min)
  • 4": 220 - 525 gpm (833 - 1,985 L/min)
  • 125 psi (8.6 bar) - Closed Rotor
  • 200 psi (13.8 bar) - Open Rotor
  • 225 psi (15.5 bar)
  • -25°F to 500°F (-32°C to 260°C)
  • 0.2 - 4,250 cP - Closed Rotor
  • 0.2 - 22,000 cP - Open Rotor
  • 1.5" - 3 ": 70 - 640
  • 4": 70 - 520
  • NP: Cast Iron
  • NPH: Ductile Iron
  • NP: Side Inlet | Top Outlet
  • NPH: Side Inlet | Side Outlet
  • Duravane
  • EC Laminate
  • Bronze
  • Iron
  • Heating Jackets: steam, oil, electric
  • Connections: NPT, Weld, ANSI Flange
  • Elastomers: BUNA, FKM, PTFE
  • Seal: mechanical, packed, triple lip
  • Performance Test
  • NPSH Test
  • Material (actual or typical)
  • Dimensional (pump only or unit)

NP Nominal Flow Rate Range

NP Series Nominal Flow Rate Range


Pump Model L W H Approx. Wt.
NP1.5 in 15-3/4 10-9/16 8-1/2 47 lb
mm 400.1 286.3 215.9 21 kg
NP2 in 16-1/2 8-3/4 8-11/16 65 lb
mm 419.2 247.6 220.6 30 kg
NP2.5 in 19-1/8 10-11/16 9-5/8 92 lb
mm 463.6 271.4 244.5 42 kg
NP3 in 19-1/8 13-7/16 12-1/4 134 lb
mm 485.9 341.3 311.2 61 kg
NP4 in. 26 1/8 16 15/16 15 1/2 314 lbs.
mm 663.6 430.2 393.7 142 kg
NPH2 in 16-7/16 10 8-7/8 64 lb
mm 417.6 254 225.4 29 kg
NPH2.5 in 19 11-1/16 9-13/16 92 lb
mm 482.6 281 249.2 42 kg
NPH3 in 19-1/16 14-1/4 12-1/16 131 lb
mm 484.2 362 306.4 60 kg
NPH4 in 26-1/8 17-7/8 15-1/2 296 lb
mm 663.6 454 393.7 134 kg

Materials of Construction

Pressure Parts Pump Models Material 
Cylinder NP1.5" – 3" Cast Iron: ASTM A48
NP4" & NPH2"-4" Ductile Iron: ASTM 536
Heads NP1.5" Cast Iron: ASTM A48
NP(H)2"-4" Ductile Iron: ASTM 536
Packing Follower NP1.5" Cast Iron: ASTM A48
NP(H)2" - 4" Ductile Iron: ASTM 536
Bearing Covers NP1.5" Cast Iron: ASTM A48
NP(H)2" - 4" Steel
Relief Valve NP(H)1.5" - 3" Cast Iron: ASTM A48
Cover NP(H)4" Ductile Iron: ASTM 536

Pump Options

Options Details
ORIENTATION OPTIONS Right Hand: INLET is to the right, when looking from driven side
Left Hand: INLET is to the left, when looking from driven side
PORTING OPTIONS NP Series: Top Outlet: Outlet 90° offset from inlet
NPH Series:  Side Outlet: Outlet 180° offset from inlet
Welded, ANSI Flange (Cl 150 RF)
Unit: Pump, Gearbox, Motor, Baseplate, Couplings, Guards
SEALING OPTIONS PTFE Packing, Component Lip
Cartridge Single Mechanical, Cartridge Triple Lip

Vane Options

Material Temperature Limits Viscosity
Duravane -25°F to 240°F (-32°C to 115°C) 0.2 - 4,250 cP
EC Laminate -25°F to 350°F (-32°C to 177°C) 0.2 - 8,500 cP
Bronze -25°F to 500°F (-32°C to 260°C) 105 - 22,000 cP
Cast Iron -25°F to 500°F (-32°C to 260°C) 105 - 22,000 cP

Elastomer Options

Material Temperature Limits
FKM -15°F to 400°F (-26°C to 204°C)
PTFE – SS Spring 0°F to 500°F (-18°C to 260°C)
Buna-N -25°F to 240°F (-32°C to 115°C)

Maintenance Kits

Model(s) Description Part Number
NP1.5 Kit - Maintenance 898928
NP2, NPH2 Kit - Maintenance 898929
NP2.5, NPH2.5 Kit - Maintenance 898930
NP3, NPH3 Kit - Maintenance 898931
NP4, NPH4 Kit - Maintenance 898932

Now hear from our customers about what they had to say about Blackmer NP Series Sliding Vane Pumps:


Installation Operation Manuals (IOMs)

NP1.5B, NP2F, NP2.5F, NP3F, NP4F, NPH2F, NPH2.5F, NPH3F, NPH4F
NP1.5B, NP2F, NP2.5F, NP3F, NP4F, NPH2F, NPH2.5F, NPH3F, NPH4F
NP1.5B, NP2F, NP2.5F, NP3F, NP4F, NPH2F, NPH2.5F, NPH3F, NPH4F

Materials of Construction

NP1.5B, NP2F, NPH2F, NP2.5F, NPH2.5F, NP3F, NPH3F, NP4F, NPH4F