Features & Benefits

Features & Benefits

Unique Features

Pump Body

The pump body is a strong one-piece casting manufactured from close grained cast iron. It can also be made from cast stainless steel or coated internally with a suitable material, typically rubber, nylon or polyurethane.

Rams

Pump rams are manufactured from ceramic, Alumina or from steel coated with a high temperature ceramic. These materials are resistant to abrasion and are hard wearing. The ram is sealed by low maintenance, auto-adjusting chevron seals. Other arrangements include traditional packed glands; high specification and flushed seals are also available.

Ball Valves

Attached to the body casting are the suction and discharge non-return ball valves. They have generous clearances to allow the passage of rag and large solids. Biased flow in the valve chamber rotates the ball which ensures that the ball and seat wear evenly and helps to prevent blockage. Access into the ball valve is via an easily removable cover.

Variable Speed Control

The standard Willett pump is designed to maintain full flow over a range of operating pressures. However the pump can be equipped for variable flow. Turndown ratio varies with the pumped fluid. Control is via PLC keypad or remote MCC.

Unique Benefits

Electronic Control Systems

Reciprocation of the Willett pump ram is controlled by a PLC interacting with proximity switches and a solenoid operated hydraulic directional control valve. Where more complex control is required, a linear transducer can be fitted.

Volume Totaliser / Flow Meter

The Willett pump displaces a fixed volume of fluid for every stroke of the pump ram. By counting the number of strokes of the pump a running total of pumped media can be given.

Blocked Pipe Detection

Should a blockage occur in the delivery pipework then the Willett pump automatically stalls via the hydraulic system. This is detected by the PLC and a volt free contact is opened which can be used to raise an alarm and/or initiate shutdown.

Sludge Density Monitoring

This patented PLC system monitors pressure differences in the delivery pipeline caused by variations in sludge density and viscosity. The pump hydraulic pressure equal to the minimum sludge density required is used as a set point. The Willett is then controlled so that it only pumps against a delivery line pressure, which is at or above the set point.

In-line Chemical Dosing

A separate chemical injection cylinder actuated and controlled by the pump hydraulic system is used to inject polyelectrolyte or other chemical directly into the pump suction ball valve chamber. This ensures good mixing and accurate control of the chemical dose.