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steam pressure relief

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#1 petrj6 OFFLINE  

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Posted March 29, 2016 - 07:26 PM

   Ok so this is a little of topic but that's why it here, I am building a new maple syrup avaporator and want to use a steam trap bubbler system.  the idea is to collect the steam pressure from one pan and pipe it up and over into another pan to bubble and preheat sap.  the pans I am making will be 30" by 20" with a formed bottom to give me about 30 sq inches of surface to the fire.  I figure this is going to boil about 4 to 5 gallons an hour.

   My question is, if I am boiling that much water IE steam out how big and how many vent pipes should I have installed so it will always vent and never build up any pressure, I am planning on using 7  tubes 1/2" in diameter and putting 2 low pressure blow of valves just to be sure.

   Thought's ????


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#2 James Bosma OFFLINE  

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Posted March 29, 2016 - 07:33 PM

Steam engines is one of my other hobbies, Picture or quick drawing of layout would be great and type of boiler and type of fire will help, 


How much do you know about boilers and the dangers of steam

Edited by James Bosma, March 29, 2016 - 07:44 PM.

#3 Chopperhed OFFLINE  

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Posted March 29, 2016 - 08:26 PM

IIRC, steam relief valves are sized by their relief capacity. Usually stated in Lbs/per hour, or BTU. It depends on the size of the steam system. I just fixed them I didn't deal with sizing. Thread size is less important than the ability to dump the required amount of volume when they open. (orifice size) The boilers I worked on in the hospital had 4" valves in tandem, with one set a few psi over the other. Smaller boilers used on drilling rigs used 2" threaded end valves in tandem. Some smaller valves also have a thermal lift device to open the seat if the temperature goes too high. ( hot water tank)

Around here, anything operating at over 14.9 PSI ( basically one atmosphere or 100 kilopascals) requires certification by the local boilers branch.

Basically, it depends on the total volume of steam you have to dump in an overpressure situation.

As stated above, a diagram or schematic would be handy.
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Posted March 30, 2016 - 08:25 AM

It is a shame you can not get together with the Maasdam family in Sully, Iowa.

They have been making Sourgum Syrup for generations and use a steam engine to grind, drive the press and boil the syrup.