Small plumbing challenge: peristaltic pump for controlled fly-sparging

[sibelman]

I just got a Grothen 500 ml/min peristaltic pump ($32.09, free shipping, ebay) for controlled fly-sparging with a Blichmann auto-sparge (See this prior thread about why this is desirable).

The pump will move hot wort from my mashtun to my brew kettle. Now I need to adapt its 1/4" tubing/barbs to the camlocks on the other equipment. Actual tubing inside the pump body is 6.4mm/9.6mm (~1/4" ID x ~3/8" OD) silicone, clamped onto 1/4" nylon-looking barbs with cable ties.

I'd prefer to avoid too many wrong turns here, as my cheap pump would start to become rather spendy, so I'm looking for suggestions. How would you bridge this gap?

Lame ideas I've had include stretching 1/4" ID silicone tubing onto 3/8" barbs on camlock females. Is that realistic? Then I would clamp the other ends of the tubing onto the pump's plastic 1/4" barbs, possibly with cable ties like the pump uses. I could potentially eliminate the dubious joint at the barbs by replacing the short provided silicone with a new longer piece, if I can find cheap-ish food-grade 6.4x9.6 tubing.

In my fevered dreams, there would be camlock-to-MFL fittings, and I'd gently stretch EVAbarrier 5mmx8mm over the pump's barbs. Because I love flare fittings and EVAbarrier. But I might need to replace the plastic barbs with stainless so they'd survive Oetiker clamping. And even though @Bobby_M loves machining/welding custom stuff, a female camlock to MFL adaptor might be too tiny a niche market to justify his talents. So these are probably not good dreams.

 

[Deadalus]

500 ml/min is 1 liter every 2 minutes, with ~3.78l/gallon that is about 7.5 minutes to pump one gallon. It would also be a slow fly sparge, not so much an issue but the transfer would be very slow. Were you planning on two, because you would need to transfer while fly sparging. Smaller batches wouldn't be too bad perhaps. Chuggers, March, Blichmann, Spike, are all about 6-9 gallons per minute off the top of my head for the HB models. Kegland has that MKII pump, it is a little more than double that price and 5 gallons/minute.

 

[Deadalus]

The pump you linked is 12V or 24V, do you have a power supply worked out? It doesn't appear to have a plug.

 

[sibelman]

Thanks for these responses, @Deadalus

Re speed and flow: gravity feeds HLT water to my MT with Blichmann auto-sparge -- a float valve that maintains a constant water level above the grain bed. The rate is effectively set by movement of wort from the MT to the kettle. The slow fly-sparge speed, about an hour to move 7.5 gallons of wort, is a good thing from my standpoint.

I've got the power part well in hand: 24VDC power supply, which also drives my still-under-construction mill motorization project. There's a switch, AC power cord, and DC power cord awaiting 1/4" plugs to attach to either mill or peristaltic pump. A wee bit of soldering and Bob's your uncle.

My challenge is the plumbing: adapting skinny peristaltic pump silicone tubing to something fat and camlock-friendly.

 

[Deadalus]

Ok, that makes more sense that you just got the one. I have a float valve but not the Blichmann, it's helpful. Gravity is just fine there as the rate is slow for fly sparging. Maybe consider a voulaf step if you haven't. Little grain bits may get through your false bottom, assuming you are using one and not a bag. Or perhaps an inline screen with finer mesh. Your pump has a narrower ID than typical. Taking apart the head is a pain if it clogs, which I have had happen a time or two with my March pump. Your choice has 4 screws plus maybe more inside.

If you wanted to keep that tubing open as much as possible, maybe use a short piece of EVAbarrier 9.5mm which is the same size tubing I'd say that is on the pump now. Then a push to connect fitting to move up to a larger size of NPT. I have a 3/8" barbed QD, but have found for HB SS fittings 3/8" NPT has fewer options. I'm not sure about camlocks as I prefer the QDs. Barbs tend to collect little bits too, I have to periodically remove wort hose QD's to remove bits from around the barb.

 

[Deadalus]

Evabarrier has the 6.3mmx9.5mm size, which is 3/8" OD. That would go on the existing barbs. Duotight fittings are from Kegland, and looking for an adapter from them, I mostly saw BSP threads, not NPT. Freshwater Systems sells 3/8" John Guest fittings, and there's one that is 3/8" ptc x 1/2" NPT. It's a male thread so you would need a female NPT thread on the camlock.

 

[day_trippr]

I don't get the utility of a peristaltic pump pushing sparge liquor to an autosparge valve. What's the gain over using a mag pump?
Note, unlike a mag pump, when that autosparge valve closes the peristaltic pump won't give a crap, it'll just keep pushing...

Cheers!

 

[Tom R]

I don't get the utility of a peristaltic pump pushing sparge liquor to an autosparge valve. What's the gain over using a mag pump?
Note, unlike a mag pump, when that autosparge valve closes the peristaltic pump won't give a crap, it'll just keep pushing...

Cheers!

HLT is gravity feed to autosparge valve, peristaltic pump is between MT and BK.

 

[day_trippr]

Ah, ok. Nothing gonna 'splode unless a valve gets left closed
But...why a peristaltic pump there? What's the gain?

Cheers!

 

[sibelman]

The idea of a constant, slow fly sparge, uninterrupted by bits of grain that easily clog a nearly closed ball (or even linear flow) valve is "the gain."

What's the gain?

As I wrote in the original post, See this prior thread about why this is desirable. Now, back to plumbing.

@Deadalus helpfully suggests putting 6.3/9.5 EVAbarrier on the pump's plastic (nylon?) 1/4" barbs, which should work -- especially if I were to swap the barbs out in favor of stainless ones that can surely withstand (necessary?) Oetiker clamping. The other end would adapt the EVAbarrier to male 1/2" NPT with JG push-to-fit adaptors and then camlock "D".

The JG adaptors are NPTF; @Bobby_M sells the other bits, and a DuoTight adaptor with BSP threads, which some posts here suggest are semi-compatible with NPT at the 1/2" size and low pressure. So maybe a can save a few bucks on shipping by buying all the bits at brewhardware.com.

Hmmm.

 

[Bobby_M]

Ok, I think you're wanting to get from 1/4" ID silicone tubing to male camlock.

I have male cam with either male or female flare but the bore is pretty tiny (3/16").
I can make you a male cam to 5/16" hose barb.

You may want to run smaller ID tubing both in and out of the pump so you COULD use 3/8" ID silicone hose which would be compatible with the regular Cam C. You'd just change out the barbs on the pump to 3/8 x 3/8" splices as I'm sure the tubing inside the pump could expand enough.


Note, if there are grain bits coming out of the mash tun, you might clog up the narrow tubing in the pump. I wonder if you don't need a screen to keep those bits out.

 

[day_trippr]

What happens when the screen plugs up?

 

[Deadalus]

What happens when the screen plugs up?

You clean the screen instead of taking apart the pump head.

 

[Deadalus]

The idea of a constant, slow fly sparge, uninterrupted by bits of grain that easily clog a nearly closed ball (or even linear flow) valve is "the gain."

As I wrote in the original post, See this prior thread about why this is desirable. Now, back to plumbing.

@Deadalus helpfully suggests putting 6.3/9.5 EVAbarrier on the pump's plastic (nylon?) 1/4" barbs, which should work -- especially if I were to swap the barbs out in favor of stainless ones that can surely withstand (necessary?) Oetiker clamping. The other end would adapt the EVAbarrier to male 1/2" NPT with JG push-to-fit adaptors and then camlock "D".

The JG adaptors are NPTF; @Bobby_M sells the other bits, and a DuoTight adaptor with BSP threads, which some posts here suggest are semi-compatible with NPT at the 1/2" size and low pressure. So maybe a can save a few bucks on shipping by buying all the bits at brewhardware.com.

Hmmm.

I think your existing barbs would handle an Oetiker clamp, the barbs are meant to be clamped.
Many people attest to using 1/4" barbs with the EVAbarrier sizes having ID smaller than 6.35mm. I haven't but since 1/4" is 6.35 mm that size EVAbarrier is the actually the correct size for the existing 1/4" barb. It's not clear, although the pump housing is clear, how the tubing prior to the barbs is attached. There's a seam along the perimeter where the pump head unscrews and that seam goes through the opening that the tubing sits in. The housing appears to clamp down a little on the tubing but it may also be more firmly attached inside. You may able to simply extend the 9mm Evabarrier into the pump head and bypass the need for the barb. Then a short run of Evabarrier to the JG fitting would allow the 1/2" NPT x 9mm (3/8") ptc adaper, with 1/2" ID tubing to the camlock. Or you could go to 3/8" ID tubing, there are JG adapters for 3/8" NPT as well. A PTC coupling might work over the existing tubing as well. It's close at 9.6mm. Then perhaps the barb could be removed.

One thing not always mentioned about barbs is that they are reducing the ID of the specific tubing size more than what might happen with other types of fittings, lookinig at the bore through the fitting here. Consider a simple coupling on Evabarrier. A ptc fitting works by gripping the outside of the tubing. I don't know whether the bore through the fitting is exactly the same as the ID, but I doubt the bore is less than the ID of the tubing, given there is 2x the tubing wall thickness to work with. Contrast that to a barbed coupling where the coupling sits inside the tubing. Each fitting used reduces the pressure. Depends on several factors, material and shape are important. Smaller diameter tubing also creates more friction per unit length. Given the pump is on the slower side, it would be helpful to reduce the number of fittings to a minimum and the tubing short I'd also suggest the pump be located no lower than the BK valve.

 

[sibelman]

I have male cam with either male or female flare but the bore is pretty tiny (3/16").
I can make you a male cam to 5/16" hose barb.

You may want to run smaller ID tubing both in and out of the pump so you COULD use 3/8" ID silicone hose which would be compatible with the regular Cam C. You'd just change out the barbs on the pump to 3/8 x 3/8" splices as I'm sure the tubing inside the pump could expand enough.

Note, if there are grain bits coming out of the mash tun, you might clog up the narrow tubing in the pump. I wonder if you don't need a screen to keep those bits out.

Thank you, @Bobby_M and @Deadalus , These are great options. A 1/4" x 3/8" splice would seem ideal for a transition from the pump's tubing to 3/8" ID external tubing that would mate with your Type C (reduced barb) female camlock.

All these possibilities seem less susceptible to clogs than the very narrow gap inside a nearly closed valve. Only experience can tell.

These ideas lead to another thought. If I found a 10-foot piece of 1/4" ID x 3/8" OD food grade silicone tubing, I could replace the existing short piece inside the pump with a long piece that should stretch onto the Type C (reduced barb) camlocks and complete the link. This would have the fewest joints and parts. So: would I be able to stretch that tubing over the "reduced" barb?

(Note: I'm reconsidering my EVAbarrier idea, both because of the narrow bore of flare fittings and because I've never used EVAbarrier on the hot side. I see no temperature specs on the web.)

 

[day_trippr]

fwiw, I've been fly sparging for years on the same rig, always at a 1 quart per minute rate, and in all that time I have never had the regulating ball valve pack up. It just doesn't happen...

Cheers!

 

[sibelman]

fwiw, I've been fly sparging for years on the same rig, always at a 1 quart per minute rate, and in all that time I have never had the regulating ball valve pack up. It just doesn't happen...

Cheers!

I'm happy for your experience, @day_trippr but my own is somewhat different. I find it difficult to reliably set the desired flow rate, partly because (though I can't see the tiny grain bits in the valve) low flow often becomes lower, especially early in the process, and even though I recirculate during mash and mash-out, producing clear wort.

I have had good or even excellent experiences like yours, but then there are the others. And it's fun to try new things that aren't too expensive.

Plus, I already have the little pump, so a bit of good money after bad should be just fine. If I get this going, I'll let you know how my solution to my minor problem (and your non-problem ) works out.

 

[whoaru99]

You clean the screen instead of taking apart the pump head.

The point is, and excuse if you know it, the paristaltic pump is a positive displacement pump.

If the output is stopped by valve or obstruction, something will give like hose pop off barb or hose blow or whatever if the motor doesn't stall first.

With positive displacement pumps a relief valve is something to be considered/advised.

 

[Deadalus]

The point is, and excuse if you know it, the paristaltic pump is a positive displacement pump.

If the output is stopped by valve or obstruction, something will give like hose pop off barb or hose blow or whatever if the motor doesn't stall first.

With positive displacement pump a relief valve is something to be considered/advised, or maybe pressure switch to shut off the pump, or both just in case.

Actually I didnt know that originally but I got the gist of avoiding a complete blockage from the emphasis placed on it 3x by day_trippr. I also got the point that Sibelman twice already pointed out their reasoning for choosing the pump and was now looking for plumbing solutions for the already purchased pump. If the pump is so delicate that it can't handle a full clog for more than a second or two, that's on Sibelman's shoulders to prevent the problem and watch the process and shut it down if it happens. And cleaning a filter if there is critical buildup before it completely clogs is still easier than taking the pump head apart. Not that I am saying that is the best solution, there are different ways to address the amount of particles getting through the mash tun prior to the pump and those will depend on brewer specific systems. I hinted at using a bag as well but I have also tried a few things myself as my original false bottom had some issues with material getting through. I can't think of a time though that material buildup stopped the flow completely during the sparge. The times that I have stopped flow from particulates was during mash recirculation and I'd say it was mainly the combination of the false bottom, my SS brewtech manifold, and not observing there was buildup inside the manifold at the tubing connection. I have however, encountered the same issue of minor buildup at the valve affecting the sparge rate, but never to the point of stoppage. I use a quart per minute as a maximum rate but am slower than that because I eyeball it and the rate I set it at visually is always slower than a quart per minute when I do spot checks. There is often some reduced flow at some point from particulates collecting at the slightly open valve. I just jiggle the valve handle but I can understand wanting to have a better idea of the rate for reproduceability. As well as exploring a cheaper alternative.

 

[Deadalus]

Thank you, @Bobby_M and @Deadalus , These are great options. A 1/4" x 3/8" splice would seem ideal for a transition from the pump's tubing to 3/8" ID external tubing that would mate with your Type C (reduced barb) female camlock.

All these possibilities seem less susceptible to clogs than the very narrow gap inside a nearly closed valve. Only experience can tell.

These ideas lead to another thought. If I found a 10-foot piece of 1/4" ID x 3/8" OD food grade silicone tubing, I could replace the existing short piece inside the pump with a long piece that should stretch onto the Type C (reduced barb) camlocks and complete the link. This would have the fewest joints and parts. So: would I be able to stretch that tubing over the "reduced" barb?

(Note: I'm reconsidering my EVAbarrier idea, both because of the narrow bore of flare fittings and because I've never used EVAbarrier on the hot side. I see no temperature specs on the web.)

Ah, but I do remember now that I looked this type of pump up previously as I did so again and what I recognized from before was how the pump works. The head is spinning and the rollers are squeezing the tubing along the half circle that the tubing occupies. So if you matched the tubing size and material, you could get a long piece and replace the existing loop and barbs. The housing is clear but I couldn't see the inside. I thought the tubing was attaching to the inside on something but it is continuous from barb to barb. EVAbarrier might be too stiff anyway to use there and I also could not find a temperature range for it.

 

[whoaru99]

@Deadalus

I get the feeling from your previous reply to me that maybe you took my post as a critique of man, method, or machine.

The point was to inform, nothing more.

Restating: when using a positive displacement pump, if the output is blocked and blockage doesn't clear or the pressure rise due to blockage doesn't open a relief/bypass back to "tank", and the motor doesn't stop turning the pump, something WILL give. Might be the pump, but more probably a fitting may blow off, a hose may burst, something along that line. Best case you have a mess, worst case may be burned by hot wort.

It's simply a notice/caution for those who may be unfamiliar with positive displacement pumps; that's all. Do as thou whilst with the information.

 

[sibelman]

notice/caution

Thanks, @whoaru99 . This is good to know.

 

[Deadalus]

@Deadalus

I get the feeling from your previous reply to me that maybe you took my post as a critique of man, method, or machine.

The point was to inform, nothing more.

Restating: when using a positive displacement pump, if the output is blocked and blockage doesn't clear or the pressure rise due to blockage doesn't open a relief/bypass back to "tank", and the motor doesn't stop turning the pump, something WILL give. Might be the pump, but more probably a fitting may blow off, a hose may burst, something along that line. Best case you have a mess, worst case may be burned by hot wort.

It's simply a notice/caution for those who may be unfamiliar with positive displacement pumps; that's all. Do as thou whilst with the information.

@whoaru99 You should have taken my post as me being exasperated that you missed the repeated attempts by the OP to refrain from discussing the choice of a peristaltic pump, this in combination with your explaining your insight into day_tripprs post about a filter. In other words, that you felt you could read between the lines for one post but ignored the more explicit instructions in the OP's. I have to admit, I didn't read the thread linked initially because the choice of the pump type was made and we were asked about the plumbing. Plus I fly sparge and use an autosparge, so no disagreement there. Which I regret not reading because the issue of the flow rate was also considered.

If the filter was on the intake side, wouldn't that just create a vacuum and not overpressure anyway? I would think at most the intake tubing would collapse, which wouldn't hurt the tubing if for instance, it was the same tubing material running through the peristaltic pump, as that portion of tubing is designed to collapse. And the pump would keep going but all it would do is keep turning the rollers over the same tubing it does all the time anyway. You did note it would be the output blocked, so again I feel like you are harping on just the pump choice without reading what was said by others, as both BobbyM and I were talking about keeping the line clear and that starts at the beginning.

@sibelman Sorry I didn't read your earlier thread right away! Also, I'm not familar much with positive displacement pumps. I did however continue reading about peristaltic pumps to get a better idea as to what catastrophe might befall you! Here are some things to consider that I found.
1. The rollers on the pump are set to account for the wall thickness of the tubing. So should you go the route of replacing the tubing, the replacement should be pretty close on thickness, unless there is a way to adjust the rollers.
2. From the wiki, and this would be for the inside the pump tubing,

The tubing needs to be elastomeric to maintain the circular cross-section after millions of cycles of squeezing in the pump. This requirement eliminates a variety of non-elastomeric polymers that have compatibility with a wide range of chemicals, such as PTFE, polyolefins, PVDF, etc. from consideration as material for pump tubing. The popular elastomers for pump tubing are nitrile (NBR), Hypalon, Viton, silicone, PVC, EPDM, EPDM+polypropylene (as in Santoprene), polyurethane and natural rubber.

3. Any tubing used should be able to handle 170F wort.
4. Any tubing should meet or exceed the the maximum pressure for the pump. I did not see it listed. It was commonly stated that these types of pumps have pressure around 2 bar ~29 psi) but it can be up to 16 bar. The roller type that you have isn't noted as being high pressure. I did find a peristaltic pump with a similar flow rate and it was rated 25 psi maximum. I found a silicone hose of the same ID that was rated 30 psi. I suspect you could find a hose sufficient to handle the pump's pressure.
5. Peristaltic pumps are noted to be good choices for slurries. I didn't pick up on why or if specific conditions were important. My thought on this is the rollers/feet would tend to compress any blockage but on the next pass fluid would flow easier.

Also #3 & #4 would apply to any fittings used.

 

[whoaru99]

@whoaru99 You should have taken my post as me being exasperated that you missed the repeated attempts by the OP to refrain from discussing the choice of a peristaltic pump this in combination with your explaining your insight into day_tripprs post about a filter. In other words, that you felt you could read between the lines for one post but ignored the more explicit instructions in the OP's. I have to admit, I didn't read the thread linked initially because the choice of the pump type was made and we were asked about the plumbing

Let's clear up a couple of your misconceptions.

There was no mention of right/wrong pump in my posts, nor any suggestion to change it, and the comments about positive displacement pump are directly related to the plumbing.

More importantly though, sibelman appears to be sincerely thankful for the information.

Thanks, @whoaru99 . This is good to know.

Even you said you learned something.

Actually I didnt know that originally

 

[sibelman]

Thanks, @Deadalus. I'm looking forward to trying the new pump once I have acquired a way to hook up its narrow tubing to the fatter plumbing of my rig. I've identified a source for food-grade silicone tubing that is super-close to the original's size, maybe even identical given that people often round when converting between metric and imperial measures.

Try not to be so hard on @whoaru99, who is also only trying to be helpful. It's true that I only sought plumbing advice, but it's good to know that, unlike the March/Chugger magnetically coupled pumps that handle blockages smoothly, a peristaltic pump could blow out a blocked tube.

I'm not planning on adding a filter -- I'm guessing/hoping that the tiny bits that partly occlude valves will not cause trouble for the peristaltic pump. None of the bits is anywhere near the inside diameter of the tubing.

@Bobby_M sells "splices" that should take me from ~1/4" to ~3/8", and some 3/8" ID silicone will fit on his "Type C" camlocks with reduced barb size. The only thing better would be if I could stretch 1/4" ID tubing over those ~3/8" barbs, avoiding the need for the intermediate splices and tubing.

 

[Bobby_M]

Thanks, @Deadalus. I'm looking forward to trying the new pump once I have acquired a way to hook up its narrow tubing to the fatter plumbing of my rig. I've identified a source for food-grade silicone tubing that is super-close to the original's size, maybe even identical given that people often round when converting between metric and imperial measures.

Try not to be so hard on @whoaru99, who is also only trying to be helpful. It's true that I only sought plumbing advice, but it's good to know that, unlike the March/Chugger magnetically coupled pumps that handle blockages smoothly, a peristaltic pump could blow out a blocked tube.

I'm not planning on adding a filter -- I'm guessing/hoping that the tiny bits that partly occlude valves will not cause trouble for the peristaltic pump. None of the bits is anywhere near the inside diameter of the tubing.

@Bobby_M sells "splices" that should take me from ~1/4" to ~3/8", and some 3/8" ID silicone will fit on his "Type C" camlocks with reduced barb size. The only thing better would be if I could stretch 1/4" ID tubing over those ~3/8" barbs, avoiding the need for the intermediate splices and tubing.

My experience with peristaltic pumps begins and ends with one that could actually handle 1/2" ID x 3/4" OD silicone tubing, but the only reason I bring it up is that it sucked up a 1/2" cube of oak and passed it right through the whole system. I brought up a filter because 1/4" ID seems small enough to choke grain bits but you might as well just try it by intentionally feed bits of milled wet grain into the flow and see what happens. There's no way to get 1/4" ID silicone over the cam reduced C. Not even close. I stock some relatively rigid 1/4" silicone tubing that I can get over a 3/8" barb, just barely. I'd take a guess that the tubing built into that pump is a softer formulation of silicone than the tubing I have. The motor probably would stall out on harder Duro tubing.

 

[sibelman]

no way to get 1/4" ID silicone over the cam reduced C.

Understood. Not surprising.

I've ordered the reduced barb camlocks and splices. I've got plenty of 3/8 ID silicone tubing, and found some seemingly appropriate tubing for the pump. Should be good to go.

sucked up a 1/2" cube of oak and passed it right through the whole system

Wow, impressive! A few grain bits should be no problem.

As ever, I'm grateful for your advice, and for all the great stuff your company has provided for my brewery!

 

[Deadalus]

I'm going to make one more attempt to clarify this for you, with bold in your comments above and points below in relative order.

I do NOT care that the OP is using a peristaltic pump.

I did NOT suggest the OP change to a different pump.

My comments about positive displacement pump are directly related to the PLUMBING.

sibelman appears to be sincerely thankful for the information.

You don't just get to bold certain words there was a whole sentence to be considered. You signed on to the pump choice by 'splaining to me what day_trippr, who didn't get the utility of it, was saying. 'Cause he was not at all thinking it was a good idea, both here and in the previous thread. The filter would have been, as I just explained, on the intake, not the discharge. Then you lectured informed me about the ouput side (twice). There was no need to quote me (and only me, not Bobby), I didn't buy the pump, I wasn't talking about the discharge side. And up to that point, sibelman was fine with the pump being a peristaltic pump, and asked to focus on the rest of the plumbing, not that it is a positive displacement pump. Address sibelman about a prv or whatever way you think is necessary, safety is important. However, these pumps are used in a wide range of applications, some hot, some caustic chemicals, some slurries with clogging probably well considered. Doesn't seem at all necessary to have the excessive mention of what type of pump it is.

 

[whoaru99]

...

 

[whoaru99]

Try not to be so hard on @whoaru99, who is also only trying to be helpful.

LOL. Indeed. What I failed to realize were the delicate sensibilites at play. But, that's fixed now. Won't happen again.

 

[sibelman]

Maiden voyage: the pump is moving my wort (based on Clone Brews recipe for Bert Grant's Perfect Porter) from mashtun to kettle. Nice and slow. A bit of a small-motor whine. Uses the same 24VDC power supply as the motor I added to my mill. Thanks, y'all, for your responses on my little project, and to @Bobby_M for counsel and parts.