Some pumps

[Adam Szendrey]

Hi,

I'm playing with the thought of buying stuff from the german ebay (www.ebay.de). The problem is...i don't speak german lol.

I found a couple of vacuum pumps, and i'll keep on searching, it seems i might get a good one cheap! But first i would like to ask you about what i've found, so here they are (which are in my current price range, or close to it):

Edwards 1.5 : 2 stage pump (top image below; sadly the owner only ships in germany, but i may be able to convince him to ship here, ofcourse i'm a bit worried about the shipment cost, but it would definetly be much less than shipping from the US...) EUR
88 (about $ 111)

Leybold D 6 A: i don't know anything about this one, i'm posting an image of it (fourth from the top) EUR 15,5 (about $ 20)

A Welch pump: large (93 kg !!) unit..looks mean (fifth image from the top) for EUR 51 ($65)

I have also found diffusion pumps:

Leybold PDW 170 (third image from the top) for EUR 5.5 ( $7 !!)

Leybold PD 400 (second image from the top) for EUR 1.50 (approx. $ 2 !!)

The price of these units (the diff. pumps) would allow me to almost pay the shipment only, but since they look quite big i guess that would be some bill alone . But they need a backing pump...

Any suggestions? I'm primaraly looking for two stage pumps (as you've told me) , so only one pump is needed.

***NOTE: I have deleted the images, and two posts with images (turbopump and another pump), as they just occupied space needlessly***

Adam

[Brian McDermott]

I find it funny that some sellers bother to sell broken turbo pumps on ebay. I saw a pump sell for $100 and you could clearly see that the blades were completely chewed up, and the whole machine looked like it would rattle if you picked it up. And yet people still bid on it! This is a strange world indeed.

[Richard Hester]

The Welch, Leybold, or Edwards pumps would probably do well for you if they aren't chewed up inside. It may (I don't know the situation in Hungary) be easier to find the proper oil for the Welch belt drive. Make sure the pump hasn't been used to pump corrosives. It may be thrashed, and it will require a retrofit and complete flush to operate with normal hydrocarbon oils. You don't want to paying for Fomblin oil (~$200/kg).

[3l]

Hi Adam:

My German is Rusty but:

"Die Vakuumpumpe ist komplett general
überholt und mit einer robusten
Lackierung versehen. Die Pumpe war sehr
unregelmäßig im Einsatz und diente aus-
schließlich zur Evakuierung an Kälte-
anlagen. "

I get:

The vacuum pump is (completely?) robust and general purpose..
This the 2 micron version.
The pump meets all regulations and requirements under the
Evaluation of (Inspectors bureau?)

Happy Fusoring!
Larry Leins
Fusor Tech

[Frank Sanns]

The vacuum pump is complete (all parts there and working). Paint is in good shape. Pump was used infrequently. When it was used it was it was used with a cold trap.

[Adam Szendrey]

Thanks guys I'm still waiting for my code though (i registered yesterday) it should arrive in 4 days. This pump has 5 days left...might be a bit close .

Adam

[DaveC]

Adam - my vote would be for the Welch pump. It is hands down the strongest of all you show. It is a very big pump, however. Can't be sure what the number is.. 1397 possibly, maybe you know.

The direct drive pumps CAN be rebuilt if they are worn, but whether by an amateur depends entirely on the internal construction. Some direct drive pumps have throw-away internal parts. The Welch pump is built like a tractor. very very stout. It will take a bit more oil, and need a big motor.

You will ultimately want a diffusion pump to reach the high vacuum region for real high voltage fusion work. For low budget , the diff pump is a workhorse. But you do have the backstreaming possibilities, if you operatre without a trap, for long periods.

The pretty blue pump you show could be only a single stage pump for servicing refrigeration systems. They typically require no lower than 100 micron to 0.5 Torr pressures.

If he said -1 Bar, (1 Bar is approximately 1 Atm) the thats only 1/10 of an ATM, or 100 Torr. Not good at all. he probably meant 0.1 Torr or 100 um.

Dave Cooper

[Adam Szendrey]

Hi Dave,

I see what you mean. Problem is that the Welch pump weights 93 kgs. Shipment would be a killer (probably cost at least twice as much than the pump itself)! And it looks quite huge, dunno where to put it .I don't know how much a "new" Welch pump costs though.

BTW it is a Modell 1397 as you have said. I'm nut sure about it's base pressure: "Enddruck bei 10 mbar Vordruck 0,000133 mbar" Which one is it??
The motor: 230 V 0.75 kW.
Only 3 hours and 33 minutes remaining for bidding, the price is now at 73,52 EUR (about 90 $). But i cannot bid since i did not recieve my code yet..oh well. I couldn't pay shipment anyway

Adam

[Richard Hull]

The Welch 1397 is probably the finest and deepest pumping mechanical pump ever made. It is a real killer of a pump and the last pump you need ever buy. It is easily maintained and will go forever if operated by a caring operator. I own one that is rebuilt and has a new 1.5HP motor on it. All up weight on its roll around cart is about 225 lbs.

Richard Hull

[Adam Szendrey]

I've recieved my e-bay code today....the pump was gone on sunday for 50 euros i think (about $62)..**(added by edit) oops that canot be..it must have been more than 90 $ since the bidding was around that last time** oh well too bad. I don't know how much shipping would have cost from germany to here...by the way hungary joins the union on the 1st of may, so from then ordering from foreign countries becomes a really good business ( no customs, which was a real pain til' now). I think i'll be able to harness the german e-bay from then .

Adam

** holy crap! i've just did a search on Welch 1397...a new unit costs 1400 to 1600 $...murphy...the best deals come when you cannot profit from them...

[plasmann]

I was using a welch 1397 for a couple years and never had a problem with it. It was a great pump, but I ended up selling it to upgrade to a dry scroll pump. I have been wanting to get away from having oil around and have a light weight pump. The scroll pump I use does the same 18CFM and pump down to at least 5mT.
For me I didn't like pumping down a 100liter chamber with a oil pump, all the oil likes to leave in the exaust. So, I was using a diaphram pump to pump it out to 2 torr, before I would valve in the welch.
Now I can just open the rough wide open and pump out the chamber in a couple minutes. Another nice thing about the scroll pump is that weighs half the weight of the 1397(100lbs) and consumes half the power(.6kW), and you can pump O2 with out having to worry about your pump exploding.
Also there are some nice diaphram pumps that will pump to 100mT, but you need to have a turbo or other high vac pump to really use these.

MIke Amann

[Adam Szendrey]

Pumps again,

I came to know a german guy who has a lot of pumps, great variety.
From single stagers through two stagers to several kinds of diffusion pumps. All cleaned, and checked, and in perfect (like new) condition. Ofyourse this can be seen on their price. He sells a small Pfeiffer/Balzers duo 1.5A, 0.015 mbar(about 11 microns) unit for 366 $ WITH shipment to hungary (the pump costs 310 $) . I would say that is quite fair don't you think? Though still a bit pricie.

BTW, a 50 kg pump's shimpment to Hungary from Germany would cost more than 400 euros (about 500 $). A more than 90 kg unit (the Welch pump) would have a similar shipment cost (somewhat more), that is why i'm looking for "lightweight" pumps. Ofcourse a smaller pump has a slow pumping rate but a fusor chamber is quite small really, so that should not be a serious problem.

Adam

[Adam Szendrey]

I've asked about the rest of his stuff, he is selling a complete high-vacuum system for 1250 $.
It includes water-cooled Diffstak 63 Oil diffusion pump, water cooled baffle, high vacuum valve, backing valve and a Edwards EDM2 two stage pump (diff. pump needs approx. 50 L/h cooling water).
It comes with a ehavy metal frame (over 50 kg). I could only pick it up by car (not that i can drive lol , shipment would be over 500 $). It can pump down below 2e10-7 mbars with LN2 trap, without a trap it can go below 5e10-6 mbars. Sounds quite good!
A similar system would cost over 5-6000 $ brand new.
He has a small air cooled (older Edwards model) diff. pump for 235 $ cleaned and tested (he sells it for 110 $ as-is without testing/cleaning it, so far he has verified that the heater works).

Adam

[Frank Sanns]

Adam,

Find an old refrigerator and pull the pump. Use this single stage pump as your roughing pump. Then buy a small used diffusion pump on ebay or from surplus for another $30-$50.

Diffusions pumps can work even at mediocre 200+ mtorr single stage roughing pump pressures. Use Dow 705 or similar diffusion pump oil that is stable against oxidation. You will be good for doing early fusor work and still have $$$ to spend on other fusor components.

Frank

[Adam Szendrey]

Hi Frank!

What is the base pressure of a refrigerator pump? What i read indicated a couple of Torr maybe, that is far above 200 mTorr.
Another question: can two refrigerator pumps be connected "in series" to achieve a much deeper vacuum?

Adam

[Frank Sanns]

Adam,

Look for the tall rotary piston pumps in refrigerators and air conditioners and not the short and fat dome shapped ones. They supposely can get down fairly well to a few torr. Two in series should get you down to 200 mTorr or better. Even a single good one should work with a diffusion pump. Early on, I tested out my diffusion pump at 2 torr and to my surprise it still pumped down quickly to 10 mtorr. Maybe somebody else on this site can give you more information from thier own personal experiences. I just hate to see you dump hundreds of dollars into shipping for a large vacuum pump when you may be able to get started at no cost for the mechanical pump if you can find something right there. The diffusion pump (or equivelent) you are going to need too but they are cheap and light to ship.

Frank
Frank

Frank



Diffusion pumps will run at higher pressures than most people think.

[Adam Szendrey]

Frank,

Thanks for the info. I'll try to aquire a couple of refrigerator pumps. The diffusion pump may be a problem unless i can get one from the german ebay. I could buy one right now for 111 $ plus shipment but it's not cleaned and tested..though it's heater works. It would cost above 200 $ if cleaned and checked. I wouldn't like to spend a lot of money and then have a non-functioning diff. pump.
Maybe this sounds silly...but is it possible to connect three fridge pumps in series? Would that get me somewhere near 10-20 microns? I just ask since it may be easier for me to get my hands on three of these pumps really cheap, than to buy a diff. pump.

Adam

[Richard Hester]

If all the parts are present and the heater is good, there's not much else that could go wrong with a diff pump. The only thing that could really be a problem is if the pump insides are caked with carbonized oil, or if the pump is rusted out. Some pumps are made with ordinary mild steel, so rusting can be a problem. Cleaning a pump that hans't been mistreated is fairly straightforward - flush the insides with acetone, then absolute isopropyl alcohol, to clean out old oil, spider nests, etc....

[Adam Szendrey]

Richard,

Then i guess i'll buy it from the guy "as-is" this month. Ofcourse first i ask about it's current condition. 110 $ doesn't seem too high...especially since i cannot get one from anywhere else . Okay i could buy a new one ofcourse...for a 500-1000 $+ . Since it's an air cooled unit it shouldn't be too heavy, shipment would be around 50-60 $ at maximum...

Adam

[Adam Szendrey]

Hi again,

Okay, so heres the situation. I can order a diff. pump for 140 $ with shipment. It comes with a piece of flexible tubing and with a high vacuum flange (brass). Heater works fine, there is some remains of oil in the pump. It's made of SS so no rust is present nor any visible damage.
The guy offered me a deal. If i buy the diff. pump and a Pfeiffer DUO 1.5 backing pump together he would charge 450 $ with shipment....i don't think i'll take the backing pump, if i can use a refrigerator pump.
BTW the diff. pump weights 4 kg. Could anybody guess on it's pumping speed, and base pressure (though that strongly depends on the backing pump i guess)? It's air cooled.

Adam

[Adam Szendrey]

Things look quite bright!
I can aquire a fridge pump from a friend for a minor fee (approx. 15 $, he lives 1000 meters from here so i'm willing to pay ).
It's a freezer/refrigerator combo (still in perfect working order), single pump. Hopefully it'll do the job well as being the backing pump of my future diff. pump.

Adam