Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Steam PRV Station

Jim123
Jim123 Member Posts: 3
I have scrolled through some of the pages of postings and didn't see any that would help me.  I'm designing multiple master details for a steam pressure reducing valve (PRV) station that the engineers at my office could use for their projects.  Problem is, I'm semi retired and have given away all my reference material (Sarco Handbooks, etc) and my reference library that included steam system articles from trade magazines over that past 40+ years.

Here are my questions:

For what inlet pressure should just a single stage, single valve  PRV station be used for 15 psig low pressure?

What about for a single stage PRV with 2 valves?  What leaving pressure should the valves be set at?

Same questions as above but for a 2 stage PRV station.

Thanks for any advice offered.

Comments

  • jumper
    jumper Member Posts: 2,230
    steam to steam

    You may find that a steam to steam generator has advantages over a steam pressure reducing station. The former is simply a heat exchanger with controls on the motive steam.
  • Jim123
    Jim123 Member Posts: 3
    Steam PRV Station

    Jumper.  The steam-t-steam HX is a good idea.  I still need advice as to my original inquiry for a PRV station.
  • jumper
    jumper Member Posts: 2,230
    pressure reducing station

    Jim, I don't understand your question . You can't simply crank down on a valve to reduce pressure. A steam pressure reducing station has to first control the amount of steam and then expand that steam to lower pressure. Sometimes it pays to use a heat exchanger to superheat the low pressure steam and then flash the cooled high pressure steam to low pressure. Not an off the shelf project. You may try PickWaterHeater or LeslieSteamValves for help.
  • Steamhead
    Steamhead Member Posts: 16,796
    edited May 2014
    You should get in touch with Spence Engineering

    their steam pressure regulators are very common, at least in our area. We use them on buildings connected to the local district steam grid:



    http://www.spenceengineering.com/spence/Regulators.cfm



    Spence also owns the Nicholson commercial/industrial steam trap line, so you might be able to deal with a single source on this job.
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • Dave in QCA
    Dave in QCA Member Posts: 1,785
    Fisher Controls

    Fisher Controls make some excellent products. Check out the website, it has some good information that might help you. http://www2.emersonprocess.com/en-us/brands/fisherregulators/steam/pressurereducing/multi-purpose/92b/pages/92b.aspx



    http://www.documentation.emersonprocess.com/groups/public/documents/instruction_manuals/d100703x012.pdf



    Back in my day as facilities mgr at a hospital facility, we had several PRV stations to reduce the boiler pressure (70 psi) to space heating pressure, 10 psi. The high pressure was necessary to operate sterilizers and a few other pieces of equipment.

    There were three building sections that were fed steam at lower pressures. Two of these areas utilized a 2 valve parallel flow Fisher Pressure reducing valves. They were set up as 1/3 -2/3 capacity and when finely adjusted would maintain a downstream pressure within 0.5 psi of the 1 psi set point. The valves were not new when I arrived and functioned perfectly during my 17 years on the job, without any failure or difficulty.

    There was also a building that had a Boyleston brand PRV. It was a one stage valve and while it funciton satifactorily, it was prone to drift of 1-2 psi. In our case it did not cause a problem, providing steam for coils in air handlers as well as a few unit heaters. There also was a smaller Boyleston PRV that provided 25 psi steam to the kitchen for steam kettles, steam ovens, etc.



    My experience in our midwest area, you can't beat Fisher Control.
    Dave in Quad Cities, America
    Weil-McLain 680 with Riello 2-stage burner, December 2012. Firing rate=375MBH Low, 690MBH Hi.
    System = Early Dunham 2-pipe Vacuo-Vapor (inlet and outlet both at bottom of radiators) Traps are Dunham #2 rebuilt w. Barnes-Jones Cage Units, Dunham-Bush 1E, Mepco 1E, and Armstrong TS-2. All valves haveTunstall orifices sized at 8 oz.
    Current connected load EDR= 1,259 sq ft, Original system EDR = 2,100 sq ft Vaporstat, 13 oz cutout, 4 oz cutin - Temp. control Tekmar 279.
    http://grandviewdavenport.com
  • Jim123
    Jim123 Member Posts: 3
    Steam PRV Station

    I've been in touch with the local Sarco rep and he was most helpful of getting me PRV piping diagrams and advise as what pressures to set the valves.  Preparation of master details is underway.  The Fischer Controls Model 925 is our basis of design specification.  Thanks to all that provided response and input.
  • jumper
    jumper Member Posts: 2,230
    commercial steam is interesting

    This thread reminds me why commercial steam is so interesting. Jim has reasons to use valves to reduce pressure. Others decide to use steam to steam although that involves two separate condensate handling facilities. Still others let steam go to waste. They all have their reasons. Laymen don't want to understand why the world is so complicated.