Archimedean screw pumps

 

 

The (Archimedean) Screw Pumps are well-known for their excellent qualities such as the Simple & Rugged design, the high efficiency, the capacity to pump raw water (even when it contains an amount of solids and debris) and their lifetime reliability.

Spaans Babcock has a worldwide reputation of being the oldest and the largest manufacturer of Archimedean Screw Pumps with a track-record of more than 30,000 screw pumps installed.

What are the main types of screw pumps?

Screw pumps can be used for flows from 15 lt/sec to 11 m3/sec maximum and are available in 3 basic types:

1. Bolts placed in the traditional concrete channel
2. Bolts placed in steel-lined concrete channel
3. The prefabricated, "ready to install" compact units

Main Applications of the Archimedes Screw

The main applications of the Archimedes screw are in sewage treatment plants for:

1. Raising the incoming sewage to a higher level without the need to install a grate before the auger
2. For pumping at the same level of recirculation sludge

 

 

 

 

 

 

 

 

Screw Pump in a Concrete Trough

The classic and most common form is the arrangement of the screw pump in an open concrete trough where the screw, suspended between the upper- and lower bearing, rotates free from the trough with a minimal gap of only a few millimeters.
 
 

Screw Pump with a Steel Trough Liner

Although this type requires a similar civil construction as the previous described ‘concrete trough’, thanks to the prefabricated steel trough liner, installation is much easier and the wear resistance of the trough in situations where lots of stones and pebbles come to the inlet, increases.
 

Compact Screw Pump (ESP: Encased Screw Pump)

For this type there is no civil construction required. A prefabricated self-supporting steel construction with integrated inlet-section, outlet-section, trough, screw pump and drive unit is preassembled and shipped in one piece, ready for immediate installation. The compact screw pump is ideal for small capacities but is also applied for capacities up to 5 m3/sec.

 

 

 

 

Advantages of screw pumps

- Slow Speed, Simple and Rugged design

- Pumps raw water with heavy solids and floating debris

- Can run without water

- No collection sump required

- Constant high efficiency with variable capacity 50 to 100%

- Pump capacity is self-regulating with incoming level

- Gentle handling' of biological flock, because of the low rotational speed and large opening between the flights

- Easy maintenance (no 'high skilled' staff required)

- Long lifetime ( > 20-40 years)

Parameters for screw pumps

• The Gap, to minimize back flow and allow deflection of pump body

• D/d = Outside diameter and Centre tube diameter, depends on length of pump

• Number of Flights (increases effecting filling)