monolithic
Hazard to Others
Posts: 436
Registered: 5-3-2018
Member Is Offline
Mood: No Mood
|
|
KNF UN726.3 FTP vacuum pump for sale!
I'm selling my KNF UN726.3 FTP vacuum pump. The manual and specifications can be found here: https://www.knfusa.com/?type=5600&file=2237
It "should" be able to pull a 10 torr vacuum but a quick test with water and a nomograph indicates ~80 torr maximum maximum. I'm not sure why. I
disassembled the pump and the diaphragms, valves, etc. are all in good working order, and I wrapped the threaded connections in a fresh layer of
Teflon plumbers tape. At any rate, it works just fine while drawing an 80 torr vacuum and the chemical resistance of the PTFE heads/diaphragms and
FFPM valves make it great for dealing with nasty solvents.
I'm asking $175 plus shipping. The box will be 14.5"x13"x10" and weigh ~15 pounds so shipping may be expensive, depending on where you live.
Pictures are available here: https://imgur.com/a/Ab9vdxl
|
|
|
Sulaiman
International Hazard
Posts: 3698
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
80 Torr is a respectable vacuum for a water aspirator, (water b.p. = c34 oC)
10 Torr would need super-cooled water as 0oC = c15 mm Hg
Probably a lower vapour pressure liquid/mixture would be required.
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
stoichiometric_steve
National Hazard
Posts: 827
Registered: 14-12-2005
Member Is Offline
Mood: satyric
|
|
That sounds like the heads are out of sync or one of them isn't working anymore.
Good luck finding replacements, because KNF stopped making those parts more than a decade ago. It's quite impossible to buy them nowadays.
Except this is a diaphragm pump. You probably misread and posted something entirely irrelevant.
[Edited on 29-12-2018 by stoichiometric_steve]
|
|
|
morganbw
National Hazard
Posts: 561
Registered: 23-11-2014
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by stoichiometric_steve  |
That sounds like the heads are out of sync or one of them isn't working anymore.
Good luck finding replacements, because KNF stopped making those parts more than a decade ago. It's quite impossible to buy them nowadays.
Except this is a diaphragm pump. You probably misread and posted something entirely irrelevant.
[Edited on 29-12-2018 by stoichiometric_steve] |
It is pretty easy to become confused, recent thread by the same author " Buchi B-169 vacuum recirculating aspirator for sale!"
Just saying
|
|
|
monolithic
Hazard to Others
Posts: 436
Registered: 5-3-2018
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by stoichiometric_steve |
That sounds like the heads are out of sync or one of them isn't working anymore.
Good luck finding replacements, because KNF stopped making those parts more than a decade ago. It's quite impossible to buy them nowadays.
|
It might be as simple as it needing more shims. Each diaphragm is shimmed at the connecting rod and PTFE piston interface. I'm not sure how or why
they determine the necessary spacing, but it's very important because the manual notes that the shims must not be mixed up or discarded during
disassembly or reassembly. As I said, the pistons and valves look to be in very good condition, and the cylinder heads show no signs of corrosion.
I believe they still make parts. When I bought it, the cooling fan on the motor was shattered. One of the repair technicians I contacted had no
problem finding a brand new fan. Also, consider that Chemglass still sells the CG-4812-30 vacuum pump, which is a rebranded UN726.3 FTP.
Update: I disassembled everything and checked it over one more time. Reassembled and I managed to distill some glycerin at about 155C. I'm at nearly
at sea level, so the nomograph indicates ~13 torr of vacuum. Looks like it does work at its rated vacuum.
[Edited on 30-12-2018 by monolithic]
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
