Designing a Twin Screw Pump - Why the Pressure Loss?

[steve2510]

I'm having to design a screw pump and I'm a bit confused about things, I've never really seen a screw pump before. I've decided upon a twin screw - screw pump and my first question is why do most examples have an outlet at a higher level than the input, surely that just leads to a pressure loss?

Example http://pimg.tradeindia.com/00110473/b/0/Twin-Screw-Pumps.jpg

 

[UltrafastPED]

See Archimede's screw: http://en.wikipedia.org/wiki/Archimedes'_screw

It was originally designed to lift water up.

 

[russ_watters]

Pressure due to height isn't loss, it is the very thing pumps are designed to create (or its twin, static pressure).

 

[Baluncore]

Search screw compressors as well as pumps.
http://en.wikipedia.org/wiki/Rotary_screw_compressor

 

[Endintears]

I'm having to design a screw pump and I'm a bit confused about things, I've never really seen a screw pump before. I've decided upon a twin screw - screw pump and my first question is why do most examples have an outlet at a higher level than the input, surely that just leads to a pressure loss?

Example http://pimg.tradeindia.com/00110473/b/0/Twin-Screw-Pumps.jpg

From a purely pragmatic standpoint, remember that in use a compressor, like all equipment, is going to be installed in a room to support some other process. These things can be big, and every square foot of floor space costs money to build, or you might be trying to fit the thing into the same footprint as a compressor being replaced. Also, imagine being in a room with a large cabinet with pipes entering and exiting horizontally. Sort of hard to walk around it, right? That means it's difficult to service, and you can't even move the thing into place without having to move pipework. While the inlet might very well be connected to a large filter element nearby, the outlet pipes are probably going to be overhead simply for reasons of access. So if you have to come out of the compressor and make a 90 degree turn upwards immediately, why not just point the outlet in that direction to begin with?