Unknown Flanges

[John Gresl]

I bought a diffusion pump recently and nor the seller or me knew what flanges are on it.

The first two pictures are the foreline. It has an OD of 1.25", ID of 1.00". On the side of it there's this groove.


The other pictures are of the top of the DP
It has an OD of 7.25", ID of 4.50"
8 Holes; It isn't CF?


I tried finding a schematic online but to no luck,

Diavac Limited Diffusion Pump DPF-4Z


Here's a link to the album if needed;
http://imgur.com/a/LjLTw

Thanks

[Doug Browning]

An ASA 3" nominal flange (7.5 " OD) looks like it could be made to fit that inlet. These can be found with 4" tube ID as well as the nominal 3" tube.

Take a look at this:
http://www.ebay.com/itm/290395827087

These also come with an ISO 100 flange on the other end, instead of just the 4 " pipe. (I don't see one currently on Ebay.)
You probably want a non- O ring groove version. Flat clearance on the ASA flange extends to 5.25" dia, so check the O ring on the pump. If there is an O ring groove on these ASA flanges, it is typically 4 11/16" to 5" diameter (or 4 9/16" to 4 7/8" for the 3" tubed version) The 3" tubed version can be found with an ISO 80 flange on the other end. ASA 3" (7.5" OD) bolt centers are at 6" bolt circle diameter (BCD) with four 3/4 " holes, so some extra holes will have to be drilled if using all 8 bolts.

[John Gresl]

Even though it only has 4 holes it would work? Or would i have to bore the remaining
I see pictures of 8 hole ASAs on the lesker website but I cant find any flanges that they sell with it.

I guess I could jut take off the flange on the foreline and attach a asa-kf converter and tha'td work fine good.

Also, whats the difference between "flat" and "grooved"? is it just whether or not the holes are threaded?

[Doug Browning]

Well, 8 holes would be better for distributing the gasket seal forces evenly, but there are plenty of Varian 6" OD flanges out there using just 4 bolts. These ASA 3" (7.5" OD) flanges are typically 1/2" or more thick, so are plenty stiff for 4 bolt use. The 6 inch bolt circle diameter (BCD) may or may not work (line up sufficiently) with the existing bolt hole pattern on the pump flange (estimating around 6.25" BCD for the pump flange). Check the bolt pattern on the pump to see. The ASA bolt holes are big 3/4 inch ones, so they do have a fair amount of leeway to match smaller bolts on the pump flange.

The 8 hole type ASA flanges are bigger ones, like 9" OD and up. There is an ISO 100-F or B (bolted ISO 100) flange which has 8 bolt holes (9 mm holes) at 5.71" (145 mm) BCD (flange OD 6.5" or 165 mm, ID 4"), and these fit to regular ISO 100 flanges. (Looks like the BCD for the pump flange is around 6.25", so not the best fit up here.)

http://www.ebay.com/itm/MKS-Nor-Cal-Ada ... 2a236d3d42
(it's ISO 100 to ISO 100-F, not ASA as claimed)

This ISO 100 slotted bolt to ISO 63 adapter might just squeak by (6.25" pump BCD, versus bolt slots from the ISO 100 5.71" BCD out to the 6.5" flange OD):
http://www.ebay.com/itm/ISO100B-to-ISO6 ... 51a0ae7c56
(sure doesn't look like ISO 63 though, more like 100 to 100, I would get some verification of the actual dimensions on this thingy first)

That foreline looks like it was made to use an O ring around that groove, with a close fit pipe and flange pushed down over it. Have to experiment there maybe, check the pipe ID of some NW flanges to see if they would fit tight to an O ring. (various O ring minor diameters are available to adjust the fit, the major O ring diameter should be just a little smaller than the groove bottom, so it doesn't roll out during insertion, drill some flange bolt holes to secure it all together then) Or just weld or silver solder a new flange on the pipe end.

Flat and grooved is referring to whether the ASA flange surface has a notch groove in it for an O ring to fit in. These come in both styles, since the standard protocol is to fit a grooved (with O ring) flange to a flat or non-grooved flange. The pump already has an O ring which appears to be about the right dimension to fit the ASA 3" (7.5 " OD) flange, so a non-grooved ASA flange would be the normal fit. You can do O ring to O ring flanges if the O rings are at non aligning diameters, or sometimes just some metal sheet cut gasket is put in between so the O rings will not ride off sideways on each other. (not ideal since the # of seal surfaces are increased, but if it works, it works,.... no leak)

By the way, "capitolareatech" had some new ASA (7.5" OD) to NW 50 (2" ID) adapter flanges listed on Ebay for like $25 I think. I don't see them currently, but they seem to have delisted everything during Christmas. Check in a week or so. For Fusor use, the NW 50 side should be plenty big, and will make finding a valve ( for throttling, if planned) much cheaper than an ISO 100 or ISO 80 valve. (but would be a bit of a waste of max pump speed for other HVac uses, considering the 700 Watts still required to generate it)

[Chris Bradley]

Check out viewtopic.php?f=10&t=4186#p21594 first.

But it may be a non-standard size - it's just an o-ring groove and a flat flange after all, so it may simply be a convenient size for the manufacturers to make.

To 'convert' to another size, use an ASA [flat] flange adapter, which is probably what that flat flange is.

Unless there is a substantial assembly on top, or that the pump is bolted to an assembly for support, in which the connection is intended to be a mechanical one, then there is no substantial need to use all the bolt holes. The vacuum will hold it in place. Polymeric o-ring seals should need no mechanical compression applied by tightening bolts up. If improvement in sealing is found by tightening bolts up to compress an o-ring seal that is not part of a joint taking mechanical loads, then it possible there is something else amiss with the mating surfaces, such as warpage or scratches.

[Doug Browning]

I see "capitolareatech" has relisted some stuff now on Ebay. I don't see the cheap NW50 to ASA 7.5" OD adapter yet. However, here is a 7.5" OD ASA to ISO 80 adapter (3" ID):

http://www.ebay.com/itm/NOR-CAL-ANC-ISO ... 256e8027ae

And a 7.5" OD ASA to ISO 100 (4" ID) adapter:

http://www.ebay.com/itm/TOWER-320001967 ... 2570495c8f

[Jerry Biehler]

It just hit me, it is Japanese so the flanges are probably a JIS standard:

http://www.ulvac.co.th/download/en02_126.pdf

[Doug Browning]

Looks like the JIS 100 nominal flange fits the #'s for the diff. pump. Searching on Ebay for JIS seems to just bring up electronic parts, thread taps and metric nuts and bolts. Vacuum flanges and especially adapters may be a long.............. wait.

[Doug Browning]

That foreline flange may already have a mating flange on it. I see some bolts installed already. If that is the case, then the grooved tube sticking up is probably just a hose fitting that takes some vacuum hose and a hose clamp. Ultra simple.

[John Gresl]

That's what I was originally going to do; attach an o-ring and a tube on to that flange, but I cannot find a KF to 1.25" PVC adapter so that I could attach the hose to my mechanical pump. Many of the sites I've checked go straight from KF-25 - 1.00"
to KF-40 - 1.50"

[John Gresl]

What if I buy a bored KF-25/40 flange and some 1.25" pipe and weld it on to the KF flange? Would the bore hole on the KF flange have to equal 1.25"? Or would I be able to weld it on something like this:
http://vacuumshopper.stores.yahoo.net/nw401.html
The NW40 Bored Weld Flange 1.00" Bore size perhaps?

Oh and I found a online schematic.... IN JAPANESE.. hah
http://www.diavac.co.jp/english/support ... F-4Z-0.pdf
I think the numbers are in mm, though

[Doug Browning]

Oh..., I see the issue now. 1.25" OD, 1.0" ID. Yeah, welding or silver soldering the 1.25 to the 1.00 could work (although the professional welded type joints are usually done around the inside of the joint to prevent air pockets, which wouldn't work here). Would be a little better mechanically and for silver solder beading if the flange pipe side indent could be bored a little further to fit the 1.25" pipe ( ie, use a lathe).

I have seen some NW25 half nipples that had 1" OD pipe on them instead of the usual 1" ID stuff. One of them could be slid into the 1.0" ID on the pump and silver soldered around the top (would have to check that a tiny amount of clearance is available, or use a lathe to slightly reduce the diameter of the inserted piece). These may be intended for use with 1.0" ID PVC tubing. Ah-ha...., the SS hose adapters on that site have just the thing. You would use it backwards: slide one into the 1" ID on the pump and silver solder, then use another hose adapter to mate the NW25's together and use 1" ID PVC tubing.

http://vacuumshopper.stores.yahoo.net/qfsshosad.html

There must be some simple hose adapter sleeve fittings around too that would just fit 1" PVC tubing to 1.25" tubing using hose clamps. Then no soldering or welding at all.

Maybe even just a metal sleeve/ferrule slid inside the 1" PVC tubing (cut off a short piece of copper tubing?), and slide the 1.25" PVC tubing over the outside of the 1" PVC tubing, with a hose clamp or two over the complete assembly.

[Chris Bradley]

Surely all you are wanting here is an ASA to KF25 flange adapter, then you'd use a KF25 bellows pipe to connect to the mech pump? No?

[Chris Bradley]

If you really insist on using a PVC pipe from this odd-ball size, then I would be surprised if you can't work a 1" PVC pipe onto this 1.25" stem.

Smear a little washing up fluid on the stem, soak the pipe's end in a boiling kettle, then work it on. May take a few goes if the stem starts out cold. Use gloves because unless the pipe is near boiling point (which should burn you) then it's probably not hot enough.

The re-enforcement may need to be cut out, or stretch it out with some pliers.

[nonstop99]

I purchased some 12" asa flanges last week here. You might want to check them out.
http://www.accuvac.com/product-category/asa-flanges/

[John Futter]

nonstop99
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