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Liverani S/P & MID Flexible Impeller Pump

Abrasive Solids & Food Grade Pump

Liverani S/P & MID Flexible Impeller Pump
Liverani S/P & MID Flexible Impeller Pump
Flow Rate Up to 44 m³/Hr
Max Head (pressure) Up to 32 M
Max Temperature Max. 100°C
Max Viscosity Up to 50,000 cP
Outlet Sizes ¾” up to 3”

Flow Rate Up to 44 m³/Hr
Max Head (pressure) Up to 32 M
Max Temperature Max. 100°C
Max Viscosity Up to 50,000 cP
Outlet Sizes ¾” up to 3”

The Liverani bareshaft S/P and hydraulically driven MID flexible impeller pumps are a type of rotary positive displacement pump. Their working principle is similar to that of a centrifugal pump however the impeller vanes are made of a flexible and durable polymer, which deform slightly as they move the liquid. This action enables fragile, shear sensitive fluids including high viscosity mediums containing particles. The SP and MID flexible vane pump models are frequently used on trucks, tractors and boats for a variety of transfer and offloading applications. 

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. PTO drives are available for the S/P models and the MID flexible impeller pumps can be supplied with an Orbital Hydraulic Motor (50 CC) or with a coupling suitable for a Hydraulic Motor.

Read our guide for more information on the operating principle of a flexible impeller pump and its typical uses.

Features of the S/P & MID Series Flexible Vane Pump:

  • Bareshaft (S/P) and hydraulic drive (MID) flexible impeller pumps
  • Pulsation free pumping action ensures easy pumping of shear sensitive liquids
  • Solids passage capability - 10mm (MINOR) 15mm (MAJOR) 25mm (MAXI)
  • Self priming up to 6m without the need of a non return valve.
  • Flexible impeller pump head can be rotated and mounted in several positions.
  • Wide range of impeller materials to cover almost any application: NBR / Neoprene / EPDM / Natural Rubber / Silicon
  • Twin Head System (2Q & 2H) can be fitted to the MAXI for doubling flow or head.
  • 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 applications are available.
  • Pump can be ordered with the connections facing in the position required (V, 90D, 90S). 
  • Pump heads are SS304 as standard for MINOR, MAJOR & MAXI (SS316 for MINI). SS 316 available.
  • Connections are Garolla as standard for MINOR, MAJOR & MAXI (BSP M for MINI & MIDEX). Others available.
  • Optional manual By-Passes (MINI, MAJOR & MAXI) for manual adjustment of the flexible vane pump capacity available.
  • Spring loaded bypass for the MINOR for manual adjustment of the pump capacity as well as operation with a nozzle.
  • Automatic barrel filling kits with stainless steel nozzle, non return valve & pressure switch can be supplied for applications where barrel or container filling is required.
  • Accessories include inverter drive for variable speed operation, dry run protection, pressure switch for automatic pumping, level sensors, remote control & radio operation.


  • S/P MINOR 40 – Bare shaft. Max 900 rpm. Max Flow 6200 L/h, max head 24M.
  • S/P MAJOR 60 – Bare shaft. Max 900 rpm. Max Flow 19560 L/h, max head 16M.
  • S/P MAXI 80 - Bare shaft. Max 600 rpm. Max Flow 41400 L/h, max head 16M.
  • MID MINOR 40 – Hydraulic orbital motor pumps. Max Flow 6200 L/h, max head 24M.
  • MID MAJOR 60 – Hydraulic orbital motor pumps. Max Flow 19560 L/h, max head 16M.
  • MID MAXI 80 - Hydraulic orbital motor pumps. Max Flow 41400 L/h, max head 16M.

Material options for the S/P & MID flexible impeller sanitary pumps:

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. EPDM and NBR impellers are available with FDA certification.

The beauty of the S/P & MID 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

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.