Dunham DH2A Vacuum Pump?

SteamCoffee

Anyone have any detailed info about this unit? Was part of the Dunham Differential Heat System from late 20's til around WWII. Have red the Dunham info on this site, 414 etc...Cant seem to find any specifications other than it was designed for total EDR of 2K ft. Are there any available? Are there equivalent Jet vacuum pump from other manufacturers for a small pump...Hoffman? Thanks!

Steamhead

Vacuum Pumps

are still available- what will you be using it on?



Here is a thread on what I think is a similar system. It was copied from the old version of the Wall, so the posts are scrambled, but if you look closely you can follow them:



http://www.heatinghelp.com/forum-thread/104173/Need-help-understanding-Dunham-system



And here is some info on the DH system, including some scans that were in the thread above but got lost in the transition:



http://www.heatinghelp.com/article/163/Older-Steam-Heating-Systems/1299/Dunham-Differential-System



Pictures would be great!

Pumpguy

My records,

and others in my network have no information on this unit. 



Typically, a liquid ring type vacuum pump is more efficient (1 hp, 12 cfm) than a water jet type, and can be built to occupy a smaller footprint.  (10 gallon tank) The only downside is they aren't available for air capacities below 10 or 12 cfm, which isn't bad but might be considered overkill for a small residential system. 



If you could provide the performance duty points you are looking for, perhaps I could be more specific.

SteamCoffee

hmmnnnnn...

Looking to perhaps replicate the Dunham Differential or a Varivac style system on a small residential system. I know the Differential System was top of the line pre wwII, not much shown in the literature after roughly 1946. Like you say, not much out there for a Vacuum only set up.....what is the lowest CFM available? More details to follow, but this is the hang up right now. BTW any VariVacs installed on something smaller than commercial-sized buildings? Their systems, and pumps especially, are huge for what I want.....