chemrox
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Posts: 2961
Registered: 18-1-2007
Location: UTM
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Mood: LaGrangian
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odd vacuum pump parameters
Here's an email exchange with a suspicious charcter, oldest last:
I can answer your questions, but let me be blunt. Who are you? Please introduce yourself. I would like to know who I am dealing with. And what your
pulling with that much vacc.
I still donot understand your application. Please contact me by land line 814-432-8590
Sent from my Verizon Wireless BlackBerry
Subject: Re: vacu/trol specs
I'm assessing its possible use in a laboratory environment for pulling
vacuums. It doesn't vary its vacuum capability according to use does it?
I'm sorry I couldn't resist. I'm trying to figure out how to convert
negative pressures to the range I'm used to. I.e. 0-760 mm (Torr)
Subject: Re: vacu/trol specs
> Sir,
> My appoligies but I can't place who you are from your email address. What
> application is this perssure related to. This info will help me answer
> your question.
>
> Thanks, Tim Lafon
>
> Sent from my Verizon Wireless BlackBerry
> Subject: vacu/trol specs
>
> Hi Tim,
>
> I'm not familiar with negative vacuum specs. Could you tell me what -600
> mm is relative to standard pressure (760mm)? Would it be 160mm?
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Sauron
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Is this the seller of the used Gast?
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chemrox
International Hazard
Posts: 2961
Registered: 18-1-2007
Location: UTM
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Mood: LaGrangian
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used Gast?
no this is a salesman from a scientific supply c. I forget which one..if you want to know I'll look it up in my office when I'm there.
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Sauron
International Hazard
Posts: 5351
Registered: 22-12-2006
Location: Barad-Dur, Mordor
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Not particularly. Lab supply houses now are very inquisitive as they are all obliged by law to be unpaid spies for the DEA.
Anyway I'd advise you to buy a used pump on LabX (first choice) or eBay (distant second choice.)
LabX tends to be scientists helping scientists and you won't be interrogated like you were by this schnook.
The pump will cost a LOT less. I strongly recommend for lab use a PTFE head diaphragm pump as these are oilless and pull a very good vacuum. The very
best are Buchi V500 and V1000, the latter can be configured for either high displacement (to deal with a large industrial rotavap, like 20 liters pot)
or low final vacuum ().1 torr) The V1000 is a pair of V500s in series or in parallel.
The KNF Neuberger PTFE diaphragm pumps are also very nice.
I got a KNF for about $200 on LabX a while back, wish I still had it. I gave it to my ex partner in New Orleans and he lost it in Katrina. Sigh.
Pump oil always ends up contaminated.
You want a pump that won't be corroded by HCl, HBr etc, where seals won't be deteriorated by solvents and that have designs that won't shunt a lot of
flammable vapors into the motor (a TENV motor is good, that is Totally Enclosed Non Ventilated.) Vacuum pumps are not all created equal and you need
to navigate through a maze of information to make a wise selection.
[Edited on 10-2-2007 by Sauron]
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