Cleaning heat exchangers

[jawsfree]

I just purchased a used mfg (1990) Alfa Laval plate and frame heat exchanger. It is in great shape, clean with no signs of corrosion. I think it came from a water to water use situation. I ran water through both side and it was clean with no smells. My question is what is the best way to clean it and what are the normal procedures for cleaning and storage before and after brew days.

Thanks
Aspiring to be pro brewer

[Thirsty_Monk]

This is what I do. I put it in CIP circuit and run it with Super CIP at 160F. Since this is your first clean, I would extend the cleaning time and may be do Caustic -> Acid cycle.

[GlacierBrewing]

I run a PBW cycle and an acid 5 cycle after every brew. I follow up with StarSan and leave the heat x packed with It until the next brew. I love how this lets me sleep at night (knock on stainless).

Prost!
Dave

[mmussen]

What I've been told when we bought a HX was that the best way to clean it is to run your cleaner (caustic or PBW) through in the reverse direction of normal flow at 1.5 times the speed you normally run wort through it. During the cleaning cycle you should also slowly open and close a valve past your HX a few times to build a little pressure on the plates, that helps press them open and clear out any gunk. I clean for 20 min on caustic or PBW (I go back and forth between the two) then rinse with acid and pack with sanitizer. And just to be safe I run hot liquor though the system in the morning getting the plates up to past 170 oF before closing the valves and let the HX sit hot till its time to send wort through it.

[TGTimm]

We use essentially the same technique as mmunsen describes. We clean between every batch, and after the final castback; leave packed with sanitizer between brews, and pasteurize before the first castback.

Every few years, I'll do a complete tear-down and hand-scrub, and inspect the gaskets; replacing if needed (have a spare set on hand). This makes me very nervous, as getting the plates out of order or reversed would be a minor disaster--I can't make heads nor tails of the diagram that our manufacturer supplies. I only do this on a day when the brewery is closed and there's no one else around to distract me or move anything.

[jawsfree]

We use essentially the same technique as mmunsen describes. We clean between every batch, and after the final castback; leave packed with sanitizer between brews, and pasteurize before the first castback.

Every few years, I'll do a complete tear-down and hand-scrub, and inspect the gaskets; replacing if needed (have a spare set on hand). This makes me very nervous, as getting the plates out of order or reversed would be a minor disaster--I can't make heads nor tails of the diagram that our manufacturer supplies. I only do this on a day when the brewery is closed and there's no one else around to distract me or move anything.

That was my hesitation on disassembling the heat exchanger that I would either damage a gasket or get some of the plates in the wrong order. I will try PBW since I don't have any access or experience with caustic. I can or course run sani clean through it as well.

[TGTimm]

I think the back-flushing is one of the most important parts of the cleaning process. Our manufacturer (Mueller Accutherm) recommends this technique. It makes sense that crud packed in in one direction will come out easier in the other. When I do tear the critter down, it's pretty darned clean in there. Caustic doesn't really break down hops residue, the main crud, but it does loosen it up nicely.

[TonyT]

At the end of every brew day we flush with hot liquor in the process direction, circulate hot PBW backwards through the system for 10 minutes, then pack the exchanger with the PBW while we cip the rest of the brewhouse and leave it packed with the PBW overnight.

Prior to knockout, we flush with hot liquor, circulate hot liquor through the HX until it reaches ~180 then pack. Just prior to knockout, we push the water out of the HX with co2, then circulate and pack with the PAA we used on the fermenter we are knocking out into. Maybe overkill with the heat and PAA, but we've never had an infection in the HX...

On Fridays we run caustic, pack the HX while we cip the brewhouse, rinse, acid, pack the HX while we cip the brewhouse, rinse, pack HX with PAA for the weekend. All cip is backward flow, all rinse is process direction flow.

[TGTimm]

Oh, yeah, since it got down to 6F last night, I should point out some winter variations....

We store the HX dry during severe cold weather, as we have a problem keeping things from freezing. We had an HX freeze a number of years ago, and it badly warped the 1" thick end plates. Clean, backflush, etc, then leave both the bottom ports open--cold H2O and product--to allow any liquid to drain. Sanitize and pasteurize before use.

[Gansett]

Heat Exchager

I just purchased a used mfg (1990) Alfa Laval plate and frame heat exchanger. It is in great shape, clean with no signs of corrosion. I think it came from a water to water use situation. I ran water through both side and it was clean with no smells. My question is what is the best way to clean it and what are the normal procedures for cleaning and storage before and after brew days.

Thanks
Aspiring to be pro brewer

Measure the exchanger from end to end while the plates are compressed and when it is not in use for a day or two,back off on the spindle to take the pressure off the gaskets. When ready to us,close to the original measurement. Gaskets will last longer.

[TGTimm]

Measure the exchanger from end to end while the plates are compressed and when it is not in use for a day or two,back off on the spindle to take the pressure off the gaskets. When ready to us,close to the original measurement. Gaskets will last longer.

Don't forget to jack your car up to relive the uneven pressure on the tires if it's going to be parked for more than 8 hours.

Our gaskets last for who knows how many years of use. I've replaced them once eight years ago, just to be on the safe side, as we bought the HX used and had no idea how much use it had seen or under what conditions it had been used. We have never had a leak or failure.

[Gbbc]

Don't forget to jack your car up to relive the uneven pressure on the tires if it's going to be parked for more than 8 hours.

Our gaskets last for who knows how many years of use. I've replaced them once eight years ago, just to be on the safe side, as we bought the HX used and had no idea how much use it had seen or under what conditions it had been used. We have never had a leak or failure.

Hi Tim,

I've used an engraver to number each plate to make sure that when you take it apart you will always replace them in the same order (also make sure your PHE always has a 'honeycomb' look from the sides). Take a measurement of the PHE on the back and front plates( top, bottom and sides) while assembled.While taking apart, take some pictures of the plates and gasket positions. I try to keep the gaskets in place when I soak them in caustic. Each gasket tends to like the plate they where moulded on.

Cheers

[CharlosCarlies]

Glad this thread came up as I was just thinking about our process yesterday while CIP'ing the brewhouse.

Basically we backflush hot caustic for 30 min or so at 1.5-2x the wort flow. From there we've only been acid cleaning the HX (and rest of the brewhouse) every couple of weeks, but I'm wondering if that isn't enough. Thoughts?

[TGTimm]

Gbbc--

That's pretty much what I've found. Our gaskets are glued to the plate on one side; it was when this glue failed we decided that we should replace the gaskets. Our HX manufacturer (Mueller Accutherm) provided us with a manual, which includes the spec for overall thickness when assembled. Getting the gaskets properly compressed to the spec. when new takes considerable force. It also has a diagram for assembling the plate, but it is a schematic that I have some difficulty understanding (that is, I don't understand it), so I'm very careful that everything goes back together the way it came apart.

The engraver is a great idea if the HX must be torn down, as are the pictures.

The main thing being, there's little or no reason to ever disassemble your HX unless you've screwed up with the cleaning, or it's a used one you're uncertain about. Be sure to have a set of gaskets on hand if you do tear it open, just in case!