Because of the open structure and large passage between the flights Archimedes screw pump can pump raw sewage without the need for a coarse screen before the Archimedean Screw Pump. Both floating debris and heavy solids are simply lifted up. This saves considerably on equipment costs for a coarse screen or maintenance!
Why do engineers select Archimedean Screw Pumps instead of centrifugal pumps?
+ Slow Speed, Simple and Rugged design
Probably the main and overall advantage of a screw pump is its superb reliability. The simple design, open structure and slow rotation speed makes it a heavy duty pump with minimal wear that operates for years without trouble.
+ Pumps raw water with heavy solids and floating debris
Because of the open structure and large passage between the flights a screw pump can pump raw sewage without the need for a coarse screen before the pump. Both floating debris and heavy solids are simply lifted up. This saves considerably on equipment costs for a coarse screen or maintenance!
+ No collection sump required = minimum head
A screw pump 'scoops' the water directly from the surface and does not need a collection sump. This keeps the pump head to a minimum.
+ 'Gentle handling' of biological flock
The activated return sludge on STP’s is a delicate biological substance. Because of the low rotational speed and large opening between the flights, screw pumps do not damage this biological flock (whereas the high speed rotating centrifugal pumps will completely shred the biological flock).
+ Long lifetime ( > 20-40 years)
Screw pumps with typical lifetimes of between 20-40 years are not unusual.
+ Pump capacity is self-regulating with incoming level
When incoming water-level goes down, at dry weather flow, the screw pump 'automatically' pumps less water. Ergo: no control system required to adapt pump performance.
+ Easy maintenance (no 'high skilled' staff required)
A screw pump requires very little maintenance. Compared to (submersed) centrifugal pumps it is next to nothing. Besides that no 'highly skilled' maintenance staff are required which makes this type of pump very suitable for remote locations.
+ Constant high efficiency with variable capacity
The efficiency-curve of a screw pump is flat on the top. Due to that efficiency characteristic, the screw pump offers even high efficiency when it works at 50% of its capacity.
+ Can run without water
A screw pump can operate even when there is no water in the inlet. Therefore it is not necessary to install expensive measures (level control etc) to prevent 'dry-running'’. The lower bearing does not need cooling.
In the wastewater treatment, the pumps that are used are either a centrifugal or positive
ReplyDeletedisplacement. Each of the pumps has different features so it is difficult to pick the right one as per the needs. To make the right decision, you need to learn the differences between both.
Click here.
Wastewater treatment
Wastewater biological treatment
Wastewater clarifier
Wastewater treatment
wastewater screw pump
archimedes screw pump