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Thread: Thomsen pumps with external seal?

  1. #1
    Join Date
    Dec 2003
    Location
    Strongsville, Ohio
    Posts
    284

    Thomsen pumps with external seal?

    Wondering who is using a thomsen pump with an external seal, specifically as their wort pump.

    We have been having problems with leakage around the shaft. We've replaced parts (seal kits, back plate, mounting bracket) with no improvement and even bought a complete pump unit from Thomsen and it developed a slow leak over about a week and a half.

    The people at Thomsen have been great and are sending us a new unit with a external seal no charge in exchange for our recently purchased pump.

    The only issue I see using one is that the external seal needs a small supply of water to keep it lubricated.

    The tech told me that this issue isn't uncommon, that its almost a 50/50 break with breweries having the same problem with leaks we have had.

    So, is anyone using one, and how has it performed if you have?

    Thanks

    JackK

  2. #2
    Join Date
    Jan 2006
    Location
    Ponderay, Idaho
    Posts
    229
    Jack is it a number 6 external seal pump?
    if so the most likely source of leak is the shattering of the ceramic seal at the back this is almost alway due to thermal shock going from hot to cold instantly such as at CIP or rinse out.
    we get at best 10 weeks out of a 60 dollar seal kit until we replace the brew house later this year we are going to live with the replacement process

    Fred
    Laughing Dog Brewing

  3. #3
    Join Date
    Dec 2003
    Location
    Strongsville, Ohio
    Posts
    284
    Thanks for the reply Fred,

    I guess I wasnt too clear in post. The pump that we have that leaked and was replaced was a standard thomsen pump with a internal seal.

    But your insight into the external seal pumps maintenance requirements and issues is what I'm looking to find out about.

    Thanks again

    JackK

  4. #4
    Join Date
    May 2012
    Posts
    23

    We had the same problem

    We had the same problem with our new Thomsen #4 external seal pump that we used for hot wart transfer. I talked to reps from Thomsen about it and they said an external water bath was helpful for that. From my understanding with him, and my own experience, hot sugary liquids pose a challenge to the pump seals and parts. The problem is if any wort leaks through the seal it crystallizes and acts as pretty harsh abrasive and wears on the seals, shaft, and backplate.

    Luckily, for us, we had another Thomsen #4 pump. The motor on it was only a 1/2 horse and we could not use it for pushing wort through our heat exchanger. This pump was an internal seal. By swapping the backplates I made our hot Transfer pump an internal seal and our other pump an external seal. I have had better luck with the internal seal but it requires it's share of maintainence. The teflon seals are cheaper but they don't last as long. We break down the pump after every use. We clean the shaft, seals and parts real good and put it back together again making sure a little sani lube gets on the o rings.

    With this maintainence schedule leakage is very rare. If it does happen we take care of it before it causes wear on pump parts. It also keeps our pump running properly without having any aeration problems.
    Last edited by russdog63; 05-17-2012 at 10:37 AM.

  5. #5
    Join Date
    Mar 2012
    Location
    Henderson, NV
    Posts
    196
    Talk to the guys at Dairy Engineering. I purchased several pumps from them that worked well for both CIP and Wort transfer. They know thier stuff and will talk to you about your issues and give you options.

  6. #6
    Join Date
    May 2019
    Location
    Bennington
    Posts
    2

    Thomsen Pumps Seal Deal

    The brewery I work for uses only external seal pumps. They all have water nozzles to cool and clean the sealing surfaces; all but the hot liquor pump, because it has no contact with the wort. Thomsen Pumps with external seals come with a ceramic seat. The seat is the part that sits in the pump back plate. Those were primarily designed for dairy or food service. In a brewery the pump is most often used in pumping sugary liquid at high temps.
    With temperature extremes of going from boiling and whirlpooling to rinsing afterwards, the ceramic experiences thermal shock and will crack. The cracks then fill with wort that doesn't completely rinse out, especially if rinsing the copper gets delayed for an hour or two. It creates a very thick adhesive that seizes the carbon seal to the seat. When the pump is turned on the shaft spins inside the seal bellows often accompanied by a high pitched squeal that is the spring spinning against the washer. Once the seal starts spinning the squeal subsides. Eventually the washer is destroyed and it releases the spring pressure holding the seal to the seat. Leakage accompanies this. Leakage can occur initially when the ceramic cracks.
    To prevent thermal shock to the seat, order your pump with a silicon carbide seat, or repair kits with a silicon carbide seat. Silicon carbide is not affected by thermal shock. Thomsen sells them. And if your pumps that deliver wort don't have water nozzles be sure to install them. Ours were made in house. Sorry if I over simplified, but some might be less experienced.

  7. #7
    Join Date
    Aug 2010
    Location
    Enterprise, Oregon
    Posts
    1,909

    Keep that seal wet!

    Wort will rapidly destroy the external seal on a Thompson (or any brand using the external seal)! You HAVE to use a water wash on the seal!

    Fortunately, this is easy to make. There's a threaded hole right above the seal. Just mount a tube that directs water over the seal in this hole. A trickle of cold water will do the trick.

    We use a C114 for our Volraluff pump. It ate seals at the kind of rate you guys are seeing--about two weeks to a month to destroy one. I rigged up a water wash for the seal and now it's been five years on the same seal!

    A washed seal is also a very good idea when using one of these for a CIP pump.

    Also check the backplate of the pump where the seal rides. This has to have a near-mirror finish. We bought one C114 that had this area damaged from the factory and it also destroyed seals. Fortunately, we bought the pump from CPE and they sent us a new backplate for free, and had us return the damaged one to be re-surfaced.
    Last edited by TGTimm; 05-30-2019 at 09:24 AM.
    Timm Turrentine

    Brewerywright,
    Terminal Gravity Brewing,
    Enterprise. Oregon.

  8. #8
    Join Date
    Nov 2009
    Location
    Moab, Utah
    Posts
    543

    Excellent Information

    Quote Originally Posted by tazbat View Post
    The brewery I work for uses only external seal pumps. They all have water nozzles to cool and clean the sealing surfaces; all but the hot liquor pump, because it has no contact with the wort. Thomsen Pumps with external seals come with a ceramic seat. The seat is the part that sits in the pump back plate. Those were primarily designed for dairy or food service. In a brewery the pump is most often used in pumping sugary liquid at high temps.
    With temperature extremes of going from boiling and whirlpooling to rinsing afterwards, the ceramic experiences thermal shock and will crack. The cracks then fill with wort that doesn't completely rinse out, especially if rinsing the copper gets delayed for an hour or two. It creates a very thick adhesive that seizes the carbon seal to the seat. When the pump is turned on the shaft spins inside the seal bellows often accompanied by a high pitched squeal that is the spring spinning against the washer. Once the seal starts spinning the squeal subsides. Eventually the washer is destroyed and it releases the spring pressure holding the seal to the seat. Leakage accompanies this. Leakage can occur initially when the ceramic cracks.
    To prevent thermal shock to the seat, order your pump with a silicon carbide seat, or repair kits with a silicon carbide seat. Silicon carbide is not affected by thermal shock. Thomsen sells them. And if your pumps that deliver wort don't have water nozzles be sure to install them. Ours were made in house. Sorry if I over simplified, but some might be less experienced.
    Taz this is excellent information on the limits of the DG setup when used with Ceramic Stationary seal. I was unaware of those limitations with respect to ceramic, and while the Silicon Carbide member is quite pricey in comparison, it is likely worth it.
    With this said AMPCO is offering a new style internal seal called the " CB + " system. Speaking to Don at CPE, the reports are good. As thus I am looking at going to one of these setups on the Kettle pump for starters. You can actually put a CB+ conversion kit on a " Waukesha " brand pump if you want to. This removes the need for wet wash.
    Star
    Warren Turner
    Industrial Engineering Technician
    HVACR-Electrical Systems Specialist
    Moab Brewery
    " No Cell Phone Zone."

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