Self Priming pump

[kshuler]

Hi everyone-

My last brew day I made an IPA using a hopback. I don't have any fancy racks to do gravity feeding, and everything is at the same level. I am using a march pump to run everything. My setup has the march pump immediately after the boil kettle, then the hopback, CFC, and ultimately pumping up to my conical fermentor.

The problem I am having is: when the pump goes dry, I still have about a gallon of fluid in my lines and hopback, and it is a ROYAL PAIN to get all of this into the fermentor.

Does anyone know if it is possible instead to have the same setup, get rid of the March pump, and instead put a self priming diaphragm pump like this one:

http://morebeer.com/view_product/17305/103556/Self-Priming_Diaphragm_Pump_for_Beer_Transfers

after the CFC and right before the fermentor? It could then suck all of the wort out of the lines and transfer ALL of it into the fermentor? Do I misunderstand the way this pump works? My understanding of the March pump is that it is happier pushing than pulling, which is why I have it hooked in where it is. Is this wrong, or does that sound right? Priming it would also be a nightmare through a hopback and CFC.

 

[Catt22]

The pump you linked to is only rated to 130F and from the B3 specs for this pump: "Has a heat limitation of 125 degrees Fahrenheit so cannot be used in brewing applications."

Your current configuration is the right way to do it, but the pump may be facing more resistance than it can handle. The prime suspect in that regard would be the hop back, but it may be a cumulative effect of all the equipment in front of the pump including the head pressure the conical presents. The standard March 809's don't have a lot of power to spare. You can calculate the head losses and compare to the pump curve to see if it can handle the task. That should tell you a lot. The wild card would still be the hop back as the resistance for those can vary so dramatically. I would try taking the hop back out of the loop first and, as a last resort, consider a more powerful pump if you are still having problems. Your CFC tubing may also be causing a large amount of resistance. What size is the tubing that the wort flows through? Many CFC's use 3/8" OD tubing which only has about a 1/4" ID. This is like trying to pump through a soda straw and presents a huge amount of resistance to the pump. Larger diameter hoses will also help reduce the system resistance. The resistance is cumulative and adds up more quickly than we sometimes realize.

 

[kshuler]

HI-

Thanks for responding. I know the pump linked is rated for low temps... my plan was to mount it AFTER the CFC, so it should only be exposed to temps around 70 degrees, not full boiling wort.

Actually the hopback resistance is extremely low.. get much more resistance form the CFC. But I don't think the power of the pump has too much to do with my problem. The problem occurs AFTER the kettle runs dry... after which I have 0.7gal in the hopback, and however much is left in the CFC and the tubing. It shouldn't matter how powerful the march pump is... it has only air to push on at this time, and since it is NOT a self priming pump, it can't pump, even though there is wort only 2 inches from the end of it. It just can't pump unless primed.

Right now I have to try to disconnect things and raise them up well above the level of the fermentor. This is a real problem with a very hot stainless steel hopback that weight about 20 lbs when full. And I don't want to waste all that beer! For a 5 gallon batch, 1 gallon of loss is a lot. Now, I didn't get 1 gallon of loss, because I spent like 15 minutes trying to gravity feed by lifting one line after another, but I wonder if I need to do this at all.... a self priming pump should, I THINK, be able to SUCK the stuff from the kettle through the CFC and right into the fermentor.

Oh, you are correct about the CFC-- only 1/4" diameter internal-- considering resistance is proportional to the FOURTH POWER of diameter-- it provides 16 times the resistance per foot as the 1/2"ID tubing everywhere else. I have a plate chiller on order, which will help this some, I hope.

Klaus

 

[Catt22]

OK, I understand the configuration much more clearly now. Yes, once the pump begins to suck air it won't be able to move anything ahead of it that's for sure and unfortunately there's no way around it with this type of centrifugal pump. The diaphragm pump should work though. They are designed for just such an application and the way you described the setup you won't have high temp wort moving through the pump. I think the issue with the diaphragm pumps at higher temperatures is that the diaphragms get very soft and just expand like a ballopn instead of moving the liquid with each stroke. IIRC, the diaphragm pumps can suck or push equally well. The only limit on the suction side is the usual theoretical 33 ft vertical max due to atmospheric pressure. I think the practical limit is actually something considerably less than 33ft, but it doesn't matter in your application as you are no where near that limit.

 

[darklord]

Does any body use pressurized air to push the wort out of the lines, hopback, CFC/chiller etc?

 

[Catt22]

Does any body use pressurized air to push the wort out of the lines, hopback, CFC/chiller etc?

I have considered using CO2 for that purpose. I would be concerned about sanitation with compressed air. I neve bothered following through as my losses are only about a quart or less in the CFC and I'm not using a hop back. I've learned to increase the batch sizes to accommodate the losses including the hop absorption in the kettle which can be substantial. I just hate coming up short at the end of the brew day. That no longer happens at my brewery.

 

[audger]

just leave an extra gallon of 180+ degree water in your HLT (if you have one, or otherwise boil some water). once your done, hook your lines up to the HLT and open the valve just untill some clear water comes out the other end. if you are careful, you dont water down your boiled wort but still save the beer in the lines and- you clean your system at the same time.

might be a little more tricky with a hopback inline though.


-edit-
also re: pumps
if you want self priming, you are probably looking for either diaphragm like the one you linked, or 'peristaltic' pumps (google it) which can be expensive. almost no impeller type pumps (march brand and others) will prime themselves. its just how they work.

 

[kshuler]

Not a bad idea just using a gallon of boiled water. Certainly a lot cheaper. I guess the question would be how much mixing of the water and wort would occur. My setup is not exactly typical. I have a RIMS system that I use with BIAB. As such, the RIMS tube is never disconnected from the system and it holds about 0.3 gallons. Combine that with the 0.7 gallon volume of my hopback and my guess is I would probably never get what looked like water coming through, just gradually lightening of the wort, and then it would be a judgement call as to when to stop. I don't always use the hopback, though, and I was wondering if this might work if I only had the RIMS tube inline? I might have to try this.