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.
Part of the positive displacement pump family are flexible impeller pumps, otherwise known as flexible vane pumps. This pump type is renowned for its ability in dry self-priming. These pumps are therefore most commonly used within applications that are required to have good suction lift capacity. Flexible impeller pumps are ideal for viscous fluids, slurries and liquids containing solids and gas in low pressure applications. Due to their hygienic construction they are also popular as a sanitary pump.
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.
Bareshaft (S/P) and hydraulic drive (MID) flexible impeller pumps
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 on request to match any of the above connection types.
Pump can be ordered with the connections facing in the position required (V, 90D, 90S). Must be mentioned at order stage.
Pump heads are SS304 as standard for MINOR, MAJOR & MAXI (SS316 for MINI). SS 316 available on request.
Connections are Garolla as standard for MINOR, MAJOR & MAXI (BSP M for MINI & MIDEX). Others available on request.
Optional manual By-Passes (MINI, MAJOR & MAXI) for manual adjustment of the flexible vane pump capacity available. In order to retain the self-priming capability of the pump the by-pass must be completely closed on initial start-up.
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:
Stainless Steel AISI 304
Stainless Steel AISI 316
Natural Rubber (NR)
St. St. / Graphite / NBR
Tungsten Carbide / NBR
Tungsten Carbide / Viton
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.