Shell-&-tube heat exchanger

New shell-&-tube heat exchanger suitable for cooling the must before yeast inoculation.

Unlike plate heat exchangers, it is MOCA certified suitable for food contact.

The relevant MOCA certificate is also issued.

Unfortunately plate heat exchangers are not certified for food contact, if you buy one try asking for an FDA or MOCA certificate for food contact.

In fact, their construction is indicated for use in boilers where the water for food use in the sanitary circuit does not come into contact with the flame-wrapped tubing.

In practice, in a boiler, the water circulating on the flame as well as circulating in the radiators also enters the primary (transferring) channel of the heat exchanger and the water that is then used in the sanitary circuit, the one we use for washing or cooking, passes into the secondary (receiving) circuit of the heat exchanger.

Another reason why plate heat exchangers are not certified (or even certifiable for contact with foodstuffs) lies in the fact that the plates are brazed together using a copper and silver alloy with a deoxidising paste additive. In addition to not being certifiable, these materials have the problem that the washing and sanitising chemicals suitable for stainless steel are aggressive for copper and silver and create microporosities where dirt and organic particles nest without a solution to remove them, creating bacterial colonies. In the long run and if contact times are not respected, micro-channels can even be created that would put the cooling water and our precious must channels in communication with each other.

Does this mean that the plate heat exchanger does not work?

Absolutely not, but functioning is one thing, functioning without contamination is another.

When cleaning, after time and time again circulating hot detergent in one direction and the other, even under pressure, if you try to give it a blow (I speak from experience) small bits of organic material continue to come out, the one trapped in the small internal channels that you see in the picture below concerning the inside of a 10-plate exchanger. The greater the number of plates, the greater the possibility of material remaining inside them

A similar problem is experienced by tube-in-tube exchangers, in which no bits remain on the inside, but protein film forms on the inside wall of the tube, which cannot be removed mechanically due to its coiled shape.

Most infections in the brewery or at home are attributable to the use of an unsuitable exchanger in the post-boil phase.

The exchanger is used at the most critical moment in any brewing process, be it by the homebrewer or the brewery, also because home brewing or microbrewing does not involve subsequent pasteurisation.

This new shell-&-tube heat exchanger, in addition to being 100% stainless steel, has the advantage that once the wort inlet and outlet camlocks have been removed, the tubes are completely open, thus allowing, in addition to pressure washing of the tube front, to enter the tubes with the pipe cleaner provided and clean with certainty every point of contact with the post-boil wort, thus removing any deposit and also the infamous protein film. Only a mechanical action guarantees removal.

Perfect cleanliness is indispensable for perfect sanitisation.

There is no point sanitising something if dirt or protein film remains inside.

Pass me the term, but as I always say, "Sanitising a dirty part is like giving underwear perfume".

Another advantage of easy cleaning is that you don't need powerful and environmentally harmful chemicals, a normal detergent is more than enough, thus respecting the environment.

The tube bundle consists of 34 precision-drawn stainless steel tubes with a diameter of 8 mm and a thickness of 0.25 mm, 50 cm long for a total length, if it were a single tube, of 17 metres.

The tubes are inserted in a deflector assembly that diverts the flow inside so that the cooling water is forced to follow a zig-zag path, thus affecting the entire outer surface of the tubes, thus increasing the yield

Downloadable streams by clicking on ‘Attached documents’▲

The cost is certainly high, but it is enough to make 6-7 breweries with contamination (and to have to risk it again) to throw away such a value, not to mention the great disappointment after so much work and time lost in the anxious wait for the tasting.

Another advantage of this shell-&-tube heat exchanger is the possibility of disassembling the whole thing PIECE BY PIECE.

►►TUBES INCLUDED◄◄

This gives the possibility, when using water rich in minerals, iron, limescale, etc., to restore the outside of the pipes to their original state, perfect and not covered with oxide. If you look at the plate heat exchangers from the fittings, you will notice that the cooling water channel sometimes shows a brown layer after a few uses; this is not rust but a ferrous deposit caused by the water used to cool, and if you use well water naturally rich in iron and lime, the situation gets even worse and the deposit becomes considerable. This deposit impairs the proper functioning of the exchanger by lowering efficiency considerably, being like a blanket that prevents proper heat exchange between the channels.

In a plate heat exchanger, this deposit cannot be removed, but in the new shell and tube exchanger, since the tubes can also be removed, this coating outside the tubes can be easily removed.

This operation is to be understood as sporadic; there is absolutely no need to dismantle it every time it is used, also because it requires a certain amount of manual skill.

Inside, however, in addition to the operating instructions, you will also find instructions for disassembling and reassembling it.

In the following graph you can see the temperature trend in the vat, the must inlet and outlet channels and the water inlet and outlet channels.

You can download the pdf by clicking on ‘Attached documents’, the chart refers to a quantity of 25 litres of must

Obviously, the colder the cooling water, the higher the yield. The test was carried out with a cooling water temperature of 13.6°C (56.5 F), with winter water around 8-10°C (in my area) the yield is considerably better.

Graph and data table downloadable by clicking on "Attached documents"▲

To complete the shell-&-tube heat exchanger, it is equipped with a practical digital thermometer to instantly detect the temperature of the outgoing wort

The heat exchanger is also equipped with an automatic overpressure relief valve for the cooling water channel preset at 4 bar. (58 Psi)

If you circulate the boiling wort but forget to open the cooling water inlet and outlet valves, the pressure reaches very high values with the risk of damage such as implosion of diameter 8 pipes (again, I speak from experience with the previous test version without the valve).

For this reason, the safety valve was added; at about 4 bar the overpressure is released to the outside.

Finishes and surface treatments

As with all BacBrewing products, this one also undergoes various treatments such as immersion pickling, electropolishing and immersion passivation for more than 3 hours with nitrite- and nitrate-free products in compliance with ASTM 380-967 USA and the EU MOCA directive concerning stainless steel parts coming into contact with foodstuffs.

Cooling water inlet and outlet connections 1/2" BSPP

Must inlet and outlet fittings Clamp 3" DN80 with elbow and clamp 1-1/2"

Downloadable quota image by clicking on "Attached documents"▲

Weight 8.8 kg (19.4 lbs)

The article consists of

• shell-&-tube heat exchanger central body, complete with tubes d.8 mm
• Clamp flange 3", 90°, 1-1/2" must inlet
• Clamp flange 3", 90°, 1-1/2" must outlet with seat for temperature probe
• 2 FDA silicone 3" clamp gaskets
• 2 Terminals 3"
• Non-extinguishable digital thermometer (2 LR44 batteries are inserted new at shipment, service life approx. 2 years)
• Stand and flat spring for digital thermometer
• Instruction manual for use, disassembly and reassembly in English
• MOCA-EU food contact parts certificate

Accessories and spare parts not included

• DN80 stainless steel collar with central thread 1/2" for hanging the heat exchanger 
• Gasket kit consisting of 70+5 pcs. o-ring silicone FDA for pipe diameter 8 mm + 2 pcs. o-ring silicone FDA pipe DN80
• Complete screws kit in stainless steel A2
• Digital thermometer
• 1 pc. Stainless steel pipe outer diameter 8 mm thickness 0.25 mm Length 50 cm

Made to order only, can be supplied in approx. 10-20 working days from order confirmation.

Totally designed, built and assembled personally by Bac (Teboni Francesco) in BacBrewing Angiari Verona, 101% handmade product Made in Italy