Screw pump PVA

irrigationwaterseawater

CATEGORY / TYPOLOGY Potable water / Lifting systems

DESCRIPTION The Archimedean screw pump PVA is designed for lifting large flow rates at low head, handling liquids containing sludge and solids. Typical applications include stormwater with solids, seawater drainage, municipal and industrial wastewater, irrigation water and sludge/water transfer in treatment plants. The pump is suitable whenever high throughput with low lift is required.

MAIN FEATURES Key operational features include a large free passage for solids and sludge, automatic flow regulation driven by the water level in the inlet well, and the ability to change flow by varying rotational speed without significant head variation. Hydraulic efficiency is high compared with centrifugal pumps for equivalent flow and head conditions.

HOW IT IS MADE The standard PVA consists of a thick central shaft with welded helical flights; the standard configuration is three flights, with one- or two-flight options available. Shaft and flights are supported by special upper and lower bearings that absorb radial and axial loads and allow rotation. The upper end is coupled to the drive gearmotor (electric motor and gearbox), typically via pulleys and V-belts or by elastic coupling on request. The lower support is generally oscillating and fitted with seals to prevent ingress of water and sand. Lubrication can be grease-fed via piping and a forced lubrication pump or be life-lubricated. A splash guard prevents spillover and improves hydraulic efficiency. Standard screw inclination is 38° (other inclinations on request). The assembly is usually housed in a reinforced concrete channel; a steel trough is available on demand. Standard construction is carbon steel with epoxy paint after sandblasting; stainless steel versions are available on request.

STRENGTHS

• High and stable hydraulic efficiency across variable flow rates
• Capable of lifting both very small and very large flow rates
• Low maintenance requirements
• Robust and reliable design for harsh water and sludge applications

TECHNICAL SPECIFICATIONS

• Model / Series: PVA
• Standard screw inclination: 38° (other inclinations on request)
• Screw flights: standard three flights; one or two flights available on request
• Shaft: thick central shaft; shaft and flights welded together
• Supports: special upper and lower supports; lower support usually oscillating with seals
• Lubrication: greased with piping and forced lubrication pump or life-lubricated type
• Drive: electric motor and gearbox (standard coupling via pulleys and V-belts; elastic coupling available)
• Housing: reinforced concrete channel standard; steel trough on request
• Construction materials: carbon steel epoxy painted after sandblasting; stainless steel available on request
• Applications: stormwater with sludge and solids, seawater drainage, municipal/industrial wastewater, irrigation water, sludge/water transfer in treatment plants
• Hydraulic: suited for large flow rates at low head; good hydraulic efficiency compared to centrifugal pumps