Swim was wondering if this water pump connected to a glass or stainless steel aspirator will suffice for all lab applications (eg. vac distillation of key products etc etc).
Will a glass one make any difference to the strength of the vacuum?
The pump itself has maximum height of 35m and can pump around 32 litres /min? can anyone help on this as I have done some basic reading on this but little has helped.
Mw
How much Horse power is the pump? I think 3/4 hp are recommended.
Swim used to have an aspirator set up for vac distill but since returned his pump and bought a used vac pump that works MUCH better. Swim thinks he spent more money on ice to keep the water in the aspirator bucket cold than he spent on a whole new pump. That whole aspirator setup was inconsistent messy and loud as fuck. Take a look at ritchie yellowjackets which kinda resemble a bee :) if swim changed ur mind about aspirators. They're about as much as an aspirator, water pump, pipes, ice and the rest of the set up on our favorite auction site... :)
Aspirator Vacuum Station (https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/aspirator.html)
(https://www.thevespiary.org/rhodium/Rhodium/chemistry/equipment/aspirator.html)
Vacuum pumps are much more expensive in Europe. However, you can construct a water-jet pump station in the UK for £ 60 or so.
I compared the specs on several different laboratory water-jet pumps (aspirators): they required between 10 and 15 L/minute at between 1 and 2 bar (10-20 m hydrostatic head). The glass water-jet pumps don't seem to be any better in performance. Bibby-Sterilin polypropylene pumps seem to be as good as any.
You can run (at least) 2 jet pumps from a water pump of that capacity.
You can estimate the pump power required as follows (but this is secondary to the pressure and capacity requirements):
e.g. 10 L/min at 1.5 bar
SI Units (sorry Americans):
10 L/min = 0.167 L/s = 1.67*10E-4 m3/s
1.5 bar = 1.50*10E5 Pa
Power = flow rate * pressure drop = 1.67*10E-4 * 1.50*10E5 W
= 25 W
Double power to allow for losses in plumbing
Power = 50 W
Assume pump has 50 % efficiency
Pump electrical power = 100 W (1/7 HP!)
Using too big a water pump and running the jet-pump at too high a flow rate won't increase its vacuum any further and will just dump more heat into the water.
I was wondering whether to try running the water pump from a motor controller to reduce the effective power.
(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000475332-file_xlzc.jpg)And this is a pdf page from a catalogue with various jet pumps:
http://www.geocities.com/wolfgang_boxhead/apps1027.pdf (http://www.geocities.com/wolfgang_boxhead/apps1027.pdf)
I haven't measured the pressure of the set-up yet but it sucks like a tart on Hugh Grant's organ.
I was thinking that if Yankees are using waterbed pumps that perhaps these are not as efficient as a laboratory pump and need more pressure and water flow to get a decent level of vacuum. I haven't managed to find a waterbed pump in the UK but then not as many Britons are sufficiently obese to require 10 hours a day lying in a flotation device.
I bought my high power vac pump from an online auction.
Ok it was sold as defect. But there was just
a little corrusion in the inner pump.
So I got it for about 30 $ incl shipping.
It destills my sassy at about 90 Celsius.
Look out for that old pumps.
Either the engine is defect and can be easily replaced
with some other old e- engine
or there`s just a little corrusion in the pump
that makes the enginepower unable to break through.
But you can clean it and everything`s allright then.
It took me just two hours.
Most used high-vac pumps that are apparently 'seized-up' and sold cheaply, are easily repaired. Seizure is usually just a broken vane spring or the little shaft inside the spring is the culprit, also chunky sludge in oil compartment can cause binding. Easily replaceable vane springs & shafts , plus a good internal cleaning will get those old Cenco's & Welch's returned to duty once again.
