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Gear Pump Selection for Vacuum Distillation

Gear Pump Selection for Vacuum Distillation

Gear Pump Selection for Vacuum Distillation

Hi all, this is my first post here, so I hope this is in the right place.

I am in the process of building a wiped film evaporator and I could really use some advice on pump selection. Right now, I am looking into different types of gear pumps for the feed and discharge lines. The evaporator body, from which the gear pumps will be pumping fluid into and out of, will be under a fairly deep vacuum of around 1-10 mTorr.

The fluid being pumped is a hot oleoresin at around 70c-100c, which becomes mostly solid at room temperature. This is a lab scale evaporator, so I would want to keep the pump output to range from 0.1 liters per hour to roughly 5 liters per hour. The feed flask will be open to atmosphere to be able to be fed continuously, and the distillate & residue discharge arms will also be pumping out into atmosphere to be able to take continuous samples. All lines will be heated and I would plan on heating the pump heads and discharge spouts as well to prevent to take care of anything solidifying on shut down and start up.

I am extremely new to all of this, but from what I understand I am going to need a pump head, a motor, and some kind of controller/VFD for each complete assembly. If this is the case, I could use advice on all 3, but my primary concern right now is the pump head. Will any old hydraulic / high pressure gear pump work for this, like one I could get on amazon for under $100 Link
work for deep vacuum applications? Or am I going to need a $1k+ mag drive liquiflo pump?

If anyone here has experience with what I described above, I would greatly appreciate your input. Thanks in advance!

RE: Gear Pump Selection for Vacuum Distillation

Not even close. That is an 11 gpm pump for hydraulic motion applications. You need a chemical process pump, which means you have to pay close attention to the internal design of bearings, materials of construction, and seals.

RE: Gear Pump Selection for Vacuum Distillation

Thanks for the reply. Do you have any recommendations for an affordable chemical process pump that will work well in deep vacuum applications?

RE: Gear Pump Selection for Vacuum Distillation

Gear pumps need to be lubricated AFAIK, so gear pump for feed, distillate sampling and residue sampling may be okay. But you also need another vac pump to maintain the vacuum on the distillate condensor - accumulator over heads? If so, does this ovhd vac pump, since there is no liquid here, have to be lube oil free ? A sketch of this setup will help. There are oil free screw vacuum service pumps.
Presume this wiped wall evaporator is the reboiler in this distillation column setup.
Note air can get into this system through pump shaft seals, so seals may need to be externally pressurised to keep out ambient air. Any rotating shaft seals on wiped wall evaporator can also leak in air if not externally pressurised. Speak to a field instrumentation engineer about any instruments that may be connected with tubing and compression fittings that may also allow air ingress.

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