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Liverani INV BS Flexible Impeller Pump

Viscous Fluids & Food Grade Pump

Liverani INV BS Flexible Impeller Pump
Flow Rate Up to 22.5 m³/Hr
Max Head (pressure) Up to 32 M
Max Temperature Max. 100°C
Max Viscosity Up to 50,000 cP
Outlet Sizes 1” BSP F up to 2½” RJT

Flow Rate Up to 22.5 m³/Hr
Max Head (pressure) Up to 32 M
Max Temperature Max. 100°C
Max Viscosity Up to 50,000 cP
Outlet Sizes 1” BSP F up to 2½” RJT

The Liverani INV BS Series is a range of flexible impeller pumps with inverter controlled variable speed and forced ventilation. These models offer all the flow control features of the INV series of flexible vane pumps but at a lower cost. It achieves this by only offering pump control from the panel; it does not feature dry run protection and the pumps are close coupled with extra fan cooling on the motors instead of a gear box. 

Flexible impeller pumps are a very versatile in the applications that are suitable for thanks to several design benefits. Firstly, thanks to their supple vanes they are able to handle not only clean, light fluids, but also viscous, solid laden slurries. Secondly, the multiple materials the impellers are made out of mean they are compatible with many fluids e.g. NBR for fats and fuels, EPDM for chemicals and hot fluids and natural rubber for water based liquids. Flexible vane pumps with EPDM and NBR impellers are able to be supplied with FDA Certification, making them a popular electric food grade pump solution. Their low shear operation also makes the ideal for handling delicate fluids that can be altered by other pump designs.

Flexible impeller pumps are renowned for their dry self-priming capability, making them ideal for applications where good suction lift capacity is needed such as the emptying of tanks, sumps and other containers. The INV-BS flexible vane pumps are widely used in transferring, filling & emptying applications.

The INV BS covers only the MINOR 40 & MAJOR 60 flexible impeller pumps. There is a larger flow capacity available from the MINOR 40 due to the ability to operate the pump up to 1400 rpm. However the minimum speed is only 175 rpm for both models as opposed to 50 rpm for their INV counterparts. Optional extras include:

1. Bi-directional radio controller instead of a wired unit which is water proof and can work up to a 100 m distance and is supplied with a charging station.
2. Supplementary 4-20 mA Connector
3. Timing System
4. Four Wheel Trolley

Our flexible vane pump guide offers more information on how this pump works and the applications it is typically used for. 

Features of the INV BS Series Flexible Vane Pump:

  • Flexible impeller pump with inverter controlled variable speed and forced ventilation
  • Pulsation free pumping action allows for the pumping of shear sensitive liquids.
  • Solids passage capability - 3mm (MINI), 5mm (MIDEX), 10mm (MINOR) 15mm (MAJOR) 25mm (MAXI)
  • Self priming up to 6m without the need of a non return valve.
  • Pumps can be run in both directions via a reversing switch integrated on the panel.
  • Pump head can be rotated and mounted in a variety of positions.
  • Requires three phase power supply due to 4 kW frequency converter panel
  • Wide range of connection types available including DIN, BSP Male & Female, Triclover, SMS, RJT, Friederich, Garolla, and Macron
  • Stainless Steel AISI 304 Pipe Fittings for easy integration of the pump into existing installations are available.
  • Garolla fittings and SS304 Materials are fitted as standard with Natural Rubber Impellers.
  • A spring loaded by-[ass is available for the MINOR 40 Model and a manual by-pass option is available for the MAJOR 60
  • Flexible vane pump heads are SS304 as standard. SS 316 available on request,
  • Automatic drum filling kits are available complete with stainless steel nozzle, non return valve & pressure switch.
  • Accessories include inverter drive for variable speed operation, dry run protection, pressure switch for automatic pumping, level sensors, remote control & radio operation. 


  • INV MINI ¾” – 0.56Kw, 1-3 phase 230-400v, 50Hz. 1400 rpm. Max flow 1440 l/h, max head 27M.
  • INV MIDEX 1” ¼ - 0.75Kw, 1-3 phase 230-400v, 50Hz. 1400 rpm. Max flow 5160 l/h, max head 27M.
  • INV MINOR 40 – 1.87Kw, 1-3 phase 230-400v, 50Hz. 900 rpm. Max flow 6200 l/h, max head 24M.
  • INV MAJOR 60 – 2.2Kw, 1-3 phase 230-400v, 50Hz. 900 rpm. Max flow 19560 l/h, max head 16M.
  • INV MAXI 80 – 4Kw, 3 phase 230-400v, 50Hz. 600 rpm. Max flow 41400 l/h, max head 16M.
  • INV MAXI Double 2Q – 5.5Kw, 3 phase 230-400v, 50Hz. 470 rpm. Max flow 65000 l/h, max head 18M.
  • INV MAXI Double 2H - 5.5Kw, 3 phase 230-400v, 50Hz. 470 rpm. Max flow 35000 l/h, max head 32M.

Material options for the INV BS flexible impeller hygienic pump:

Description Stainless Steel AISI 304 Stainless Steel AISI 316 Nitrile (NBR) Natural Rubber (NR) Neoprene (CR) EPDM Silicon (VMQ) St. St. / Graphite / NBR Tungsten Carbide / NBR Tungsten Carbide / Viton
Part List
Pump Body X X
Impeller X X X X X
Mechanical Seal X X X


1.Changes in Mechanical Seal Materials are at cost. All pumps are supplied with Ceramic / Graphite / NBR as standard.

2.Changes in Impeller Materials are Free of Charge. All pumps are supplied with Natural Rubber Impellers as standard.

3. EPD and NBR impellers are available with FDA certification

The beauty of the INV BS flexible impeller pump is it's versatility. Thanks to the following features it is an option that can be applied to many application requirements. 

  • Handles solids up to 25mm – Supple impellers bend to pass viscous fluids and slurries up to 50,000 CP and solids without damage to the pump
  • Applies low shear – Ideal for delicate, shear sensitive fluids that can be damaged or altered by other pump types such as cream that gets thicker when whipped.
  • Reversible operation – Allows cleaning solution to be ran through after use for hygienic pump applications, and tank to tank transfer applications.
  • FDA approved – EPDM and NBR impellers with FDA certification for food grade pump assurance. Stainless sanitary enclosures and Tri-clamp couplings available.
  • Smooth, steady pumping – Provides a consistent flow ideal for dosing ingredients, chemicals and process fluids and filling finished product into packaging.
  • Self-priming up to 6m – Enables the emptying of tanks and drums without a non-return valve or regular manual priming being required. 
  • Various mounting positions - Allows for versatile installation to fit the pipework at hand
  • Various accessories available - Trolley for portability, bypass valve for nozzle dispensing, control panel, variable speed drive, level sensors and dry run protection

Flexible impeller pumps are a versatile design of pump for relatively low pressure applications, mainly with thanks to their impellers being produced in a wide range of materials for fluid compatibility including food grade applications. As the impellers are made of a supple, rubber type material that is able to bend, flexible vane pumps are also able to handle viscous fluids and those with solid content without causing damage. They also apply little shear to the pumped medium, making them suitable for shear sensitive fluids and their ability to be operated in reverse makes them ideal for tank to tank transfer. These design benefits make them suited to many applications including:

Marine Applications Industrial Applications
  • Contaminated bilge water pumping
  • Oil and lubricant transfer
  • Black and grey water pump
  • Sludge and slurries
  • Fish waste pump
  • Tank to tank seawater transfer
  • Food processing and transfer
  • Dairy products
  • Brewery and distilleries
  • Chemical pumping
  • Waster water pump containing solids
  • Oil and lubricants
  • Viscous fluids, sludges and slurries
  • Soaps, creams and gels
  • Paints, glues and detergents

Related Products

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  • Liverani INV Flexible Impeller Pump

    Liverani INV Flexible Impeller Pump

    • Up to 72 M³H
    • Max. Head 40M
    • Max. Temp 100°C
    • ¾” BSP M up to DN 100 mm Outlet
    • Max. Viscosity 50,000 cP

    Find out more

Castle Pumps are fully accredited to enable you to buy with confidence. Our accreditation includes: Our accreditation A division of the CTS Group, Part of Flow Max Ltd.