Paul One Pipe System Details

Pumpguy

I'd like to learn more about Paul One Pipe Systems.



Is there more than one type air valve used? I've been told that the thermostatic valve used has 1/8"NPT male threads on the steam side and 1/4" NPT female threads on the vacuum air line side. Are there any others that are larger and would have a greater air flow capacity?



What is the usual air line vacuum; 5" Hg, 10" Hg, more?



How is the air line vacuum regulated? Does the vacuum pump run start-stop controlled by a vacuum switch, continuous with air bleed to limit vacuum, or something else?



If anyone has first hand experience with these issues, I would appreciate their comments.

moneypitfeeder

search the wall

Hi, if you search the wall for paul system you come up with some threads that may be of interest to you, and the names of people that have dealt with them, here's one for example;

http://www.heatinghelp.com/forum-thread/127945/Paul-system-retrofit

Bio

Hoffman No 2

According to this book you were able to do One pipe vacuum using and Hoffman No 2 air vent, not sure if they are still made, but Hoffman No3 are and combine with Hoffman 76 it just might work, it is certainly interesting reading, maybe one of the pro's has seen it out there



http://www.heatinghelp.com/files/articles/1310/128.pdf

http://www.statesupply.com/steam-traps/hoffman-specialty/air-vents/hk1010

Bio

Next year's project

I will try it my self for next winter, seems doable, pexsupply also carry the Hoffman No3

http://www.pexsupply.com/Hoffman-401419-3-1-8-x-1-4-Angle-Steam-Air-Line-Valve-11733000-p

Pumpguy

Paul Systems Details

I have read the thread that moneypitfeeder refers to as well as anything else I can find here and anywhere else but haven't found the information I am asking about. 



Most of the information refers to using a venturi (aka jet, ejector, eductor) as the vacuum source.  These require a motive fluid, (air, steam, or water) flowing through a nozzle under pressure.  Unless there is an abundance of this motive fluid available, and it's available at the required pressure, this method of producing a vacuum can be quite wasteful.  A typical small water eductor (Penberthy) has a very low air capacity in terms of CFM.  Also, a water eductor type vacuum pump is not as efficient as a good liquid ring vacuum pump in terms of CFM/HP.  A good liquid ring vacuum pump can give you 14 CFM/HP while a 1 HP water jet vacuum pump will do around 9 or 10.



Some posts mention using a shopvac as a vacuum source.  That might work as an experimental set-up but I wouldn't expect long service life if it was for daily season long operation.  Also, being a centrifugal fan type vacuum producer, the CFM curve drops off pretty steeply as you go out in vacuum, and the maximum dead end vacuum from what I've seen is about 8" Hg. 



What I am really trying to find out is the air volume requirements for a vacuum pump used on a Paul System, and how the vacuum pump operated. 



I was told today that the airline vacuum on a Paul system is around 5" Hg. and the  vacuum pump operated start - stop from a vacuum switch.   Is there anyone with experience that can confirm this information  or offer something different?