Mono has designed and manufactured its largest W Range progressing cavity pumps ever built. The four pumps have been ordered for two major wastewater treatment plant upgrade projects, and at 11-metres long they will have double the size and double the capacity of pumps normally used for this type of sludge cake application.

The pumps will be used in a duty/standby configuration on a Cake Reception and Buffer Silo unit. This unit will house 4 feeder channels to transfer sludge cake from the silos into the specially-designed, 4-metre long hoppers of the W Range pumps. Injection points have been included in the hoppers so that additional material can be blended in to create the required degree of dry solids sludge. The W Range pumps, which also feature dry-run and over-pressure protection devices, will transfer the sludge to a pre-thermal hydrolysis process at a rate of 60.5m3/h.

“We worked extremely closely with the client to create the pumps which would handle the huge capacity which the customer required,” says Mono’s Senior Applications Engineer, Paul James. “They were tailored to meet the customer specific requirements and include features such as specially-designed blending points, and a variable pitch auger which will ensure a consistent sludge transfer without any imbalances in the feed stream.”

The pumps were also designed to be supplied in 3 parts to provide ease of installation and maintenance, as the pumps are situated in a chamber beneath the silo. Each part has its own lifting point, together with a single lifting point for when the pump is fully assembled.

Mono’s EZstrip ‘maintain-in-place’ technology will allow the pumps to have a retractable feed chamber which can be disconnected by removing only a few screws, thus giving quick and easy access to the pin joint area for removal of any blockages or compressed cake. This significantly reduces the time needed to strip and rebuild the pumps - usually without the need to disconnect or remove any pipe work - and so generates significant increases in availability, plus savings on maintenance costs.