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In-line chemical dosing pump

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  • In-line chemical dosing pump

    Anyone have suggestions for a relatively inexpensive, easy to use in-line chemical dosing pump?
    need to for acid additions to sparge water

  • #2
    Without knowing the volume of acid you will be adding it's hard to suggest a specific pump, but I would highly recommend a peristaltic pump that fits your desired ML or L per minute.

    If you want to spend money its hard to beat the Endress-Hauser Liquiline controller with an inline pH meter. The feedback can adjust your peristaltic pumps rate of flow to match a desired perimeter. Pricey though. Most peristaltics I have worked with have an adjustable speed, but unless you have real-time pH monitoring, you will likely have to set it and adjust differently. In your case you ought to be able to find a relatively cheap pump that has a specific set flow rate and match your sparge/run off rate to get the desired dosage per Liter/Gallon.


    • #3
      Dosing pump....

      These are made in thousands of different models. I've used diaphragm pumps similar to those on boiler feed with good luck. Make absolutely sure that you select one that is fit for strong acid and that is absolutely food grade. They are not expensive. You just need to discuss your needs with a pump supplier. They can pick one out for you.
      Phillip Kelm--Palau Brewing Company Manager--


      • #4
        Diaphragm pumps are a great choice also. They are typically used in boiler treatments because they are often able to overcome high pressure. I suggested the Peristaltic for a couple reasons. First, you do not have to specify pump parts that are chemical compatible. Instead you use a tubing which is a proper size and chemical compatible. It is cheap and easy to replace as needed. They also do not have to be primed in order to pump properly and tend to be a bit cheaper.

        A diaphragm is an excellent choice if you are willing to spend a bit more money. They tend to use a little less energy over time, and are equally reliable. They can overcome high line pressure.

        Both need some maintenance over time. Both can be adjustable speed motors. Diaphragms need cleaner fluids to avoid clogging check valves(not an issue in this case), peristaltic has to be monitored for hose wear or roller wear over time. Diaphragms seldom leak outside the pump, but neither do properly tubed and maintained peristaltic. Both can dose quite accurately if sized properly. As I said earlier, both are good choices. Find what matches your desired dose rate, and budget.


        • #5
          Obviously, we don't know what your water mineral content is, but the fact that you are wanting to dose acid suggests that the pH is too high due to carbonate / bicarbonate. I suggest you treat the cold water before it passes through the heat exchanger, or is added directly to the hot liquor tank prior to heating as this means you could simply top the tank up with a know quantity of water, and then add a calculated quantity of acid, mix thoroughly and check the pH to ensure it is where you want it - 7, and then heat up.

          You will suffer far less mineral scale build up in the wort chiller, where you are going to heat much of the water, and as a result, need to carry out less intensive acid cleaning of the chiller liquor side. The controls are a lot simpler - calibrated water tank, calibrated acid measuring flask of some sort and desktop / handheld pH meter - not in line pH meter, with proportional dosing pump and flow meters on the liquor supply to ensure that the dosing pump output is actually going to be dosing proportionally - and you can correct if under dosed before it is too late.

          Keep it simple - add acid to the cold liquor tank. That way you also treat the mashing liquor and get the right mash pH.


          • #6
            I am guessing the poster is actually wanting to bring down the pH of the sparge water below 7 to the upper 5 range since he mentioned for sparge water and not brewing liquor. It is commonly believed by a newer era of brewers that they will extract tannins if the sparge water is not acidified to this range. Dick might believe as I do, in that you will not have an issue in sparging with normal pH 7 water. Buffering capacity of the mash should keep you well below the tannin range provided you are not collecting much wort below 2.5*P. Only an abnormally high water pH (carbonate/bicarbonate), or an abnormally high mash pH would require sparge water acidification, IMHO. I have met a handful who will add acid in the HLT after mashing but before sparging. Personally don't think this is necessary.

            As far as keeping it simple, I would suggest acidulated malt over treating the CLT/HLT, unless again you have abnormally high pH (carbonate/bicarbonate) brewing water and are concerned it will overpower the buffering capacity when sparging. Again quite easily measured, adjusted, and won't carry over into subsequent brews. We've actually stepped away from HLT/CLT additions and have been plenty happy with the results. I don't like to add anything unnecessary to my brews (but I'm not one of those people). I'll use what benefits my beers. Our water is usually slightly acidic, although it changes daily. Very low mineral content because it's RO. We add what we need back. If you are adding lactic/phos for the total brewing liquor volume, I like Dicks assessment of treating cold side to pass through the HX.

            As far as an inline pH meter, it definitely beats a bench top or handheld when used with something like the EH Liquiline. It automatically adjusts the dosing pump speed with real time measurements to ensure the optimum range is met constantly. Display is digital in real time so you can monitor. Faster than a bench top or even a handheld. In fact it uses an almost identical pH probe as the bench top. I would not use inline without the feedback functions however because it would be too difficult for you to adjust manually on the fly.

            I like the acidulated malt for the short explanation, but the post asked for a pump suggestion (wink).


            • #7
              London water contains a lot of temporary hardness - witness the speed with which a domestic kettle scales up. We used acid dosing in large London breweries, or in Tadcaster where we had similarly high (probably higher at Tad) levels of bicarbonate from the boreholes.

              I accept what you are saying about acidulated malt, but being a UK brewer, acidulated malt is not common in the UK - without checking, I think only Weyermann supply here.

              I agree with E&H meters, having used loads of E&H instrumentation over the years, but unfortunately if the prices of them are anything like their other instruments, one of these hardly contributes to a low cost solution. But I totally agree that if you are going for in-line dosing, continuous measurement of the achieved pH, i.e. use of an in-line instrument is essential. Not used liquiline as in my previous lives, all instrumentation and dosing kit was linked via PLC systems - looks a neat piece of kit though.