FAQs

Absolutely yes ! provided they are correctly installed with particular attention to suction line configuration and provision made for air to be evacuated while the pump is priming the suction line.

Noise varies as to the speed of the pump and where it is operating on the performance curve. A Gorman-Rupp Super T series pump operating in mid curve will typically be less than 70dBA at 1m with most of the noise coming from the standard foot mounted motor, towards top left of curve the noise increases on any pump. If your application is particularly sensitive to noise, run it by us and we will give you an honest expectation on the noise level

We can handle up to 3” spherical solids on Gorman-Rupp T series pumps (from T4 through to T10), the T3 can handle 2.5” solids, the T2 1.5” solids. Solids handling is not all about free passageway, the Super T Series Eradicator system deals with rag build up as it enters the eye of the impeller (Click here for more information on the Eradicator system)

Vee belt drive means the pump performance can be changed by the pulley ratio while using a full size impeller. If the pump is direct coupled rather than vee belt driven, an impeller trim or variable speed drive (inverter) is needed to vary performance. On our design of baseplates and motor stools there is also the added advantage of the rotating assemblies being removable via the motor stool cavity without disturbing the pump casing or motor.

That depends on the application. On fairly light duties like a raw sewage pumping station it is not uncommon for a pump to last over 30 years, we have plenty out there in the field over that age. On highly abrasive applications like mud or grit pumping, obviously the lifespan of the pump is less but we can offer austempered ductile iron (hard iron) parts for those applications to extend the life as far as we can

The pumps are surface mounted which means easy access for maintenance without using lifting gear or a involving a confined space entry (in the case of dry well pumps).

Yes, incredibly easy since they are surface mounted with built in features such as external shimless adjustment, easy access fill and drain oil ports, removable back covers for inspection and easy replacement of key components such as suction check valves, impellers, and wear plates.

NPSH is Nett Positive Suction Head. For a pump to function correctly NPSH must be positive. A positive system is where after a vacuum has been formed and the pump is fully primed, there is enough atmospheric pressure available to push the liquid into the pump and through the pump at the required rate. As part of making a pump selection we do something called a NPSH calculation where we calculate NPSH available from the system by considering things like static suction lift, suction pipework losses, vapour pressure correction, altitude correction and atmospheric pressure safety factor. From that we subtract the NPSH required by the pump (which is published on the performance curves at the flow range). If that calculation is positive then the pump will perform as required, if its negative something has to change in the system or pump selection.

An automatic air release valve provides an easy passage for air to be evacuated while the suction line is being primed. They need to be installed before a discharge non return valve. The discharge non return valve holds the pressure back while the air release valve does its job. Generally we say if the pump needs to develop air pressure of over 5m to lift a discharge non-return valve, then an automatic air release valve should be fitted.

In most cases the we recommend the air release line should be submerged approx. 150mm below low level cut out in the sump, that’s unless there is a large difference (say over 3m) between stop and start levels in the sump, or if the air release valve is being used to break a syphon (if static discharge head is negative, ie runs down hill). Submerging the air release line helps to retain prime in the suction pipework (in the event of the internal check valve failing to seat properly due to a small obstruction).

Yes, if the effluent contains those types of items, then we recommend the Gorman-Rupp Super T Series fitted with Eradicator system. Click here to find out some more information

If the pump operates on a suction lift, then generally we say 4% is a good maximum guideline. If the pump operates on a flooded suction, then this can be pushed out to 5% -7% but we recommend on site trials since the sludge characteristics at each site can vary, its not all about % solids.

A few golden rules;

• Keep the suction line as short and simple as possible.
• Make sure you have individual suction lines.
• Give consideration to the route air will be evacuated, use automatic air release valves at their correct setting in conjunction with discharge non-return valves. Submerge the air release line outlets 150mm below pump stop level.

Generally submersible pumps (either wet well or dry well) will be less initial cost than Gorman-Rupp T series. The better return on investment (ROI) on Gorman-Rupp pumps comes from the far longer asset lifecycle, reduced civil engineering costs, and reduced maintenance costs.

No, we carry extensive stock at our Peterborough location which enables us to ship common replacement pumps and spares same day or next day. Gorman-Rupp also have a huge inventory of pumps at spares at their Netherlands and USA based warehouses which we expedite using very efficient International Freight companies.

Wet prime pumps need some liquid retained in the casing and use a recirculation method to prime. Gorman-Rupp pumps are designed to retain enough liquid in the casing to re-prime even if the internal suction check valve does not seat fully. They have advantages of dry prime in the fact they do not require any other equipment to prime.

Dry prime pumps use either a venturi or diaphragm device to prime the suction system. The pump is a traditional end suction centrifugal type. Dry prime type pumps can handle large volumes of air in the case of long suction lines and can often be used where dry running (ie intermittent incoming flow into the sump) occurs.

Centrifugal action creates a low pressure point at the eye of the impeller, the partially full casing throws a mixture of air and water into the priming chamber (an integral part of the pump casing), the water in that chamber recirculates back into the suction via a port at the bottom of the casing, whilst the air rises to the top of the priming chamber to be vented off via the air release line or discharge system. This process continues until all the air is evacuated from the suction system, at which point the pump is able to develop discharge pressure and lift the discharge non return valve.

No, most hot oil pumps are built from cast iron / ductile iron / steel parts.

Yes, the seals need to be capable of handling liquids from 180 degrees upwards requiring special features and materials. Most standard mechanical seals are not suitable. Cornell pumps either use metal bellows type 609 seals or ICS2 cartridge seals with Aflas elastomers.