Sciencemadness Discussion Board - looking for specific vacumn pump

looking for specific vacumn pump

sonytvpenny - 28-12-2012 at 06:54

Looking for a decent 10 mmhg vacumn pump. Any suggestions?

Thanks for any input

smaerd - 28-12-2012 at 13:59

Do you really think you'll find a vacuum pump that will only pull that much?
Are you aware that a vacuum can be adjusted?

IrC - 28-12-2012 at 14:29

You could get a cheap Gast pump and add a needle valve to allow control of air bleeding in to control vacuum. This valve is used on swamp coolers. Many hardware retailers carry them at least seasonally.

sonytvpenny - 28-12-2012 at 18:46

Quote: Originally posted by IrC

You could get a cheap Gast pump and add a needle valve to allow control of air bleeding in to control vacuum. This valve is used on swamp coolers. Many hardware retailers carry them at least seasonally.

thanks for the reply back,

How would i combo a gast pump and a needle valve to control vacuum. Could you be more specific pleaseee. For a different route would i be able to use a vacuum regulator? Been googling, ahhhh head hurtsss. < newbieeeeeee

[Edited on 29-12-2012 by sonytvpenny]

[Edited on 29-12-2012 by sonytvpenny]

IrC - 28-12-2012 at 23:12

Something so simple as this should not require Google. You demonstrate a complete lack of thinking through for yourself such a simple concept. This does not bode well for anyone with a desire to involve themselves in science in any field. By it's nature science is inherently dangerous. You may wish to think about this. I assume you can figure out one of the ports on the pump sucks, and that you would be connecting a line between the vacuum port on the pump and that which you wish to pump down. Insert the valve in the line, path through the long section at the bottom. As you open the valve air sucks in the top inlet on the valve thereby reducing the vacuum going to the object you are pumping down. I am unsure how this could be explained any simpler than the above text.

DJF90 - 28-12-2012 at 23:15

IrC: Any idea what that valve is called technically? (Or where I can buy it from?). I searched for "needle valve with bleed" but it didn't turn up anything like what you pictured, what with the "hose barbs"/compression fittings(?) and all.

IrC - 29-12-2012 at 01:56

Never looked into it's name or where you would find it if not around your area. Just stuff every summer in hardware stores for water control in the desert SW. $2.99 at Alco in Tucumcari last time I bought one. Plus tax. Coolers and misters only work well in desert climates. My use: Main water feed to cooler on shop straight through. Right in front outside: you use pipe and joints to build overhead framework. Cover with sun blocking plastic sheet which does not impede air flow through it. Along framework you run 1/2" PVC pipe which you drill a gazillion tiny holes in. Cap end, feed other end to top outlet on valve. Now when your working on car you open needle, water flows through piping out tiny holes creating a steady mist which evaporates before it hits ground meaning you never get wet. When it's 120 degrees outside your working on whatever in nice misty cool air out of the sun. Crap this is hard to verbally describe. Anyway virtually every hardware store in the SW has bins of them for cheap. As to online locating, don't know never tried.

Almost forgot: I used a few on my vacuum station, top port to tank which was a vacuum reservoir. Works great and if you get good at those compression fittings they do not leak. Once when moving I pumped system down to 29 ish on gauges. Is how I store it. Did not use system again for 3 years, looked at gauge and it was a needle width below where I left it 3 years prior. It takes practice to get your vacuum plumbing this tight and my system has more than 20 compression fittings in it. Long ago I posted a pic of it on some vacuum thread around here somewhere. Small note: on my vacuum system I do not use the fittings you see above, they are for plastic cooler line. The same valve also works with ball shaped compression fittings used for 1/4 Cu tubing, which is why the vacuum holds so well. However if you plan on building the outdoor misting system use the fittings in the pic above.

[Edited on 12-29-2012 by IrC]

hyfalcon - 29-12-2012 at 04:22

I should read the whole post before replying. Where's my coffee?

[Edited on 29-12-2012 by hyfalcon]

IrC - 29-12-2012 at 07:21

Quote: Originally posted by DJF90

IrC: Any idea what that valve is called technically? (Or where I can buy it from?). I searched for "needle valve with bleed" but it didn't turn up anything like what you pictured, what with the "hose barbs"/compression fittings(?) and all.

I did your work for you, Home Depot.

http://www.homedepot.com/buy/plumbing/valves/watts-3-8-in-br...

You have got to be kidding me, $8.60 the lousy rip off bastards. Not even the price of gold has risen that fast.

Hexavalent - 29-12-2012 at 09:36

Quote: Originally posted by IrC

I did your work for you, Home Depot.

You might want to note that he is in the UK, where we don't have access to 'Home Depot'.

Either way, would this be mounted directly to the vacuum pump itself or following a short length of tubing? I guess it depends on what fittings the pump has.

IrC - 29-12-2012 at 11:53

Quote: Originally posted by Hexavalent

Quote: Originally posted by IrC

I did your work for you, Home Depot.

I do not see why it would matter a leak anywhere along the vacuum line is going to reduce the suction at the end. The original question was about a certain level of negative pressure, obviously the pump is going to create greater vacuum so either reducing the pump action (unlikely with a synchronous AC motor, could overheat motor) or introducing a steady controlled leak is the easy way to achieve this.

CaliusOptimus - 29-12-2012 at 12:16

Just wanted to drop in here and share a wonderful resource with you all. It's a free book with everything you've ever wanted to know about vacuum systems.

http://www.oerlikon.com/leyboldvacuum/en/documents/download-...

Choose "Fundamentals Of Vacuum Technology" on the left.

Ephesian - 29-12-2012 at 17:37

I have a welch 3 directorr V vacuum pump model 8910. It will bring you down way below your requirement. Refurbished price 1499.00

sonytvpenny - 29-12-2012 at 17:43

Quote: Originally posted by IrC

Something so simple as this should not require Google. You demonstrate a complete lack of thinking through for yourself such a simple concept. This does not bode well for anyone with a desire to involve themselves in science in any field. By it's nature science is inherently dangerous. You may wish to think about this. I assume you can figure out one of the ports on the pump sucks, and that you would be connecting a line between the vacuum port on the pump and that which you wish to pump down. Insert the valve in the line, path through the long section at the bottom. As you open the valve air sucks in the top inlet on the valve thereby reducing the vacuum going to the object you are pumping down. I am unsure how this could be explained any simpler than the above text.

thank you for your essay, Clearly that text is nothing but an ignorant statement. What you just said implys that everything that seems so simple to you should also apply to others. I'am pretty sure you probably asked questions that are simple to others but mind boggling to you. Thanks for the help nonetheless. Science is new to me, I have just found this as a new hobby i enjoy, Whats wrong with asking questions. Isn't that what forums all about.

[Edited on 30-12-2012 by sonytvpenny]

Vargouille - 29-12-2012 at 18:13

You could try a water aspirator. It won't get down to 10 mmHg, but it'll get relatively close.