Paul questions

Patrick_North · April 2010

In sniffing around for info on converting one pipe steam to a Paul system, I keep running into head scratchers. I’m a ways off from implementing anything- I just want to get as much of the leg work done as I can in advance. Here’s a bunch of questions that’d I’d appreciate some help with.

 

I think it was Gerry Gill (in an old thread) who hypothesized that only a shallow vacuum was necessary- indeed, even a modest vacuum could have the effect of holding condensate in risers and causing water hammer. So question #1-

Anybody know how deep a vacuum was created in the original systems? The pumps I’ve snooped at are all in the 30”Hg+ neighborhood. 

 

Any opinions on control schemes? Tie the pump to the burner, thermostat, ???

 

Next, I’m wondering about how using one fixed vacuum source would play out as individual Paul valves shut down. It seems that as the ends of mains and then individual radiator see steam one might want to reduce the vacuum, but it sounds like the opposite will happen. Does the system require a vacuum breaker of some sort to avoid a spike in vacuum when, say, all of a sudden only a single Paul valve is open? 

 

Over the last few years I’ve been doing my darndest to get my radiation to match heatloss, room by room. I do, however, have one radiator that is still grossly oversized. I’ve yet to move this out because… it’s grossly oversized. In a Paul system, do you think it’s especially important that radiators at least proportionately match heat loss? With “unassisted venting,” this isn’t an issue for me, but I can imagine that if this rad got hot all the way across along with all the others, well- it’d be a hot time in the old town. Would there be some way to install a trv inline?

 

Trying to find an attractive, tough, easily repairable material for running air lines. Pex is out as is coiled copper tubing. Is there such an animal as rigid ¼” copper pipe? Ideas?

 

I love the warm weather, but I miss the steaming season already.

Thanks,

Patrick

Paul Fredricks_3 · April 2010

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I don't pretend to know much about the Paul process. But I was thinking about the vacuum you want to create. If the pumps you are looking at all draw down to 30" vac, maybe you need a different type of vacuum: an actual vacuum. Maybe not a full fledged Dyson or Electrolux, but something small. Maybe something like the little vacuums they make for computer keyboards. I know the CFM would be low, but I can't imagine you need to move large volumes to create the vacuum you need. And I'd think they can't draw a very deep vacuum. Unless this pump is also used to remove all the air from the system. Then maybe a vacuum that's a little bigger, like for a car. Obviously you'd have to do some adapting to make these work electrically.

Just thinking.

Paul Fredricks_3 · April 2010

tubing

They must have small rigid tubing, like that type used for pneumatics, or brake lines.

Unknown · April 2010

Paul Tubing

Hi- The Paul system also interests me. For tubing I think you could use polysulfone. It has high temperature resistance and is reasonable in price. Here's a link with some info: http://www.solvayadvancedpolymers.com/static/wma/pdf/4/0/6/UDG2004.pdf

Polysulphone is also being proposed for piping in a new concept steam system "pipe within a pipe". The steam is in the center and the condensate return on the outer ring. Here's a link to a description: http://www.wipo.int/pctdb/en/wo.jsp?WO=2009117296&IA=US2009036886&DISPLAY=DESC

I had been envisioning a "dump tank" where you would build use a small vacuum pump and "build" a vacuum in a fairly large tank that would then be used to evacuate the steam system. This is quite a common practice in the plastic vacuum forming industry. Though after reading Paul Fredrick's reply I think he is on to something here and will now reconsider the "dump tank" idea. Something like a shop vac would provide a instant large volume vacuum though not producing a very high state of vacuum.

I'm not quite sure what the ultimate goal is. Is it producing a fully enclosed system at maximum vacuum or just a vacuum assisted air evacuation system? It maybe that just the latter is produces enough benefit to be practical.

- Rod

- Rod

Patrick_North · April 2010

What's the goal?

Well, I'd guess most of the benefit of lowering the boiling point of water went by way of the coal boiler. As your coal fired died down, you could still squeeze out some steam. As my boiler is ON or OFF, I imagine there'd be limited utility without more advanced controls.

I gather the benefits come into play more strongly with quicker distribution. If you can decrease the time from "steam at boiler" to "hot radiator," you've saved as much fuel.

I think.

Patrick

Techman · April 2010

Vacuum

I dont know Richard about Paul systems.But a 30' Hg is about the deepest vacuum you can get.In AC and refrigeration we can't get a deep vacuum if there is even a little moisture ,let alone water, in the pipes. I guess I'm missing alittle or a lot of something here.

Patrick_North · April 2010

Not missing anything...

Probably not missing anything, Techman- just illuminating how little I know about vacuum pumps! Just wondering what the most appropriate modern equivalent would be to the old steam turbine setups.

A Google search turned up a Heating Help thread from years past where "Long Beach Ed" says he retrofitted a Paul setup with great success.

Long Beach Ed, you still out there?

Patrick

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