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Best pump for application

Robomoo
Robomoo Member Posts: 7
edited August 2023 in THE MAIN WALL
Different application for you guys. I do dairy farm welding contracting, milk lines for robotic milkers. Looking for a circulating pump for water flowing through a plate heat exchanger. Plate cooler is 24" tall 8" wide, 14 plates. 1" inlets and outlets, vertical mounted. Trying to move water from a large poly tank above the cooler. From outlet of (bottom) of cooler to top of poly tank is approx 12 to 14 ft. Pump can be feed from bottom of the tank to pump below tank. Gravity primed. Pump needs to push through plate cooler (inlet at top, outlet bottom 24" lower, then the 14ft straight up to top of tank) then up to top of tank. Normally we use a pressurized tank ( DHWT or retention tank) and circulate with a small Gundfos circulating pump. Has been tried with this open system, but the pump could not lift to top of tank. Can't create the pressure differential on an open circuit, Wrong pump for application, Looking for ideas of a small pump 24gpm fine better wont hurt. Looking for volume not pressure. Pump will need to run 24/7. Only off time is 20min 3 times a day when robots wash, the plate cooler is drained of cooling water at that time. Need something simple, reliable and inexpensive :D (I know those three words should not be in the same sentence) Sorry for the long question, just wanted to make sure I explained right what I am looking for. TIA. Great forum been reading it for years. Radiant underfloor with ground source heat pump in my home for 30yrs.

Comments

  • hot_rod
    hot_rod Member Posts: 22,703
    Does it need to be stainless steel?
    I build these pump/ purge carts with a Grundfos CM series pump. This CM 5 cart will do about 32 gpm, open hose. This is a 1-1/2 hp.

    The CM 1 we use, 1/2 hp is good for about 13 gpm. There is a wide range of sizes.

    Although there is some cast iron touching the fluid in this series of pump.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Robomoo
    Robomoo Member Posts: 7
    hot_rod said:

    Does it need to be stainless steel?
    I build these pump/ purge carts with a Grundfos CM series pump. This CM 5 cart will do about 32 gpm, open hose. This is a 1-1/2 hp.

    The CM 1 we use, 1/2 hp is good for about 13 gpm. There is a wide range of sizes.

    Although there is some cast iron touching the fluid in this series of pump.

    Thank you That gives me a model to read up on on the Grundfos site. Wood be wise to be an all stainless pump. The water has a fairly high iron content. Has to be able to survive on neglect. Once running nobody will see it until it fails. Thanks
  • hot_rod
    hot_rod Member Posts: 22,703
    If it is a dairy or food processing involved, is stainless steel a requirement? Bothe inside and outside for wash down?

    Is this potable water, do food products touch that side of the plate HX? If no, then any pump body would work, iron, brass, composite, stainless.

    The CM is very configurable if you have been to the website. Different RPM, different amounts of impellers stacked. The position of the outlet can be rotated also.

    Next you should get the spec on that plate HX at 24 gpm flow, what is the pressure drop across it?

    Three things needed to size the pump:
    Type of fluid
    Gpm
    Head, pressure drop through the devices in the circuit.

    In some cases temperature also.

    We have sold hundreds of those pump/ purge carts with these Grundfos CM pumps, a quality built product, no question.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • STEVEusaPA
    STEVEusaPA Member Posts: 6,505
    Robomoo said:



    ...Once running nobody will see it until it fails...

    I'd pipe in two in parallel with ball valves. Keeps you going and easy change out.

    There was an error rendering this rich post.

    Zman
  • Zman
    Zman Member Posts: 7,609
    Finding the resistance of your heat exchanger is going to be the most important detail of the sizing exercise. I would also note that with a low static head pressure open system like yours, getting the pump as low as possible below the tank as well as correct pipe sizing between the tank and the intake of the pump is critical to prevent pump cavitation. In general, shoot for 2 ft/sec on the inlet pipe, this often means that the inlet pipe to the pump is a size bigger than the outlet.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Robomoo
  • Robomoo
    Robomoo Member Posts: 7
    STEVEusaPA said:

    Robomoo said:



    ...Once running nobody will see it until it fails...

    I'd pipe in two in parallel with ball valves. Keeps you going and easy change out.

    That is how we would like to do it, like this. The place needing the pump wont spend that kind of money. They will go with the most basic


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