Archives for posts with tag: watts density

Jamie at 07897 246779 loves breweries and brewers, who provide happiness and hangovers to us all. Could live without the hangovers, mind you! The older I get, the longer they seem to last.

Remember all of the stuff that applies to all water immersion heaters, plus the key consideration for breweries is ease of cleaning.

Our existing ranges of immersion heater had limitations when used in brewery applications.

The II Range has many benefits, including bespoke screwplug size, immersed length, double stat pockets, etc, all with a 2 week leadtime, BUT as you can see from the images (particularly the 5th) our aim of maximising the length of 8mm diameter element, hence double looping rather than merely U bending, leads to a fair old ‘clump’ of elements.

Now, we are fully aware that all of you happy brewers are only boiling clean water (ha, ha) and are fastidious in cleaning thoroughly with a jet wash between every brew (chuckle, chuckle), but still, this ‘clump’ led to build up of ‘mystery stuff’ over time, leading to hot spots, element splitting and heater death.

So, in conjunction with one of our Italian suppliers, we designed the BI Range. These are a 10mm, U bent element, which has masses of gap between the elements (see pictures 2, 4 & 6) to enable efficient jet washing of the element to clean off any deposits. We will never be able to deviate from the specs on the website, as we have to buy in bulk with horrible lead times. But thankfully, we seem to have pitched the immersed lengths just right, and the watts density at around the 60w/in² mark, seems to be just right.

Even with the antique gear that some of you chaps are recycling for 21st century brewing, no one has needed any screwplug size other than 2.25″, tho I suppose we could throw on an adaptor to make them 2.5″ if needed.

So if you fancy buying an immersion heater that was actually designed for brewers, give me a call on 07897 246779. Feedback from new and existing customers is greatly appreciated and collated at G##gle & FB.

Thanks for visiting.


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Call on 07897 246779.

Remember all of the stuff that applies to all water immersion heaters, plus for oil heaters our target is to get the watts density down to 12w/in² or below for heavy, industrial oils, and 25w/in² or below for lighter cooking oils.

POIL Oil Imersion Heater

Oil Imersion Heater

The II Range has many benefits, including bespoke screwplug size, immersed length, double stat pockets, etc, all with a 2 week leadtime. The 8mm elements can be double looped to fill your maximum available immersed length with a large overall length of element. As can be seen in the fifth image on our PII web page, the elements drop from the screwplug to your maximum available immersed length, before looping back up to within a few inches of the screwplug, before dropping back to full immersed length, then returning back up to the screwplug. This allows us to fit nearly twice the length of element possible in a plain U bent element. For example, in 24″ of maximum immersed length, we could use an 84″ element double looped.

if you have a very large tank with a massive maximum available immersed length, you may choose not to double loop, but to have plain U bent elements over a meter in length.

Informational content provided by Jamie at …who would love you to leave a comment.

Informational content provided by Jamie at

Call on 07897 246779.

For the full shilling version, see the web authority on everything, Wikipedia, or an informative, if uninspiring, site referenced on the wiki page.

The extremely abridged version – its an electrically powered rod which applies direct heat to liquids and gases.

And finally, the version. Here is one I chopped up earlier –


Video for those that are allergic to reading.

The top end is the terminal, sometimes a spade connection, but more usually a thread, washer and bolt combination, geared at holding the electrical connection, ie, incoming wire, in place.

Below the nuts is a white plastic plug which serves as a seal against ingress of moisture and also to hold all of the important bits inside in the middle of the tube, away from the sheathing.

The sheathing material is the outer housing, the solid casing, usually made of a metal, in this case Incoloy 800, a stainless steel variant. This serves to encase and protect the important bits, protecting them from whatever is being heated, ie, oils, chemicals, etc.

The white compacted powder inside the tube is magnesium oxide powder, which serves as an insulator against electrical leakage, but as a conductor of the heat generated by that electrical current.  It serves to hold the filament wire centrally within the tube so that contact with the sheathing material is all but impossible.

Finally, the tiny wire seen protruding at the bottom of the picture is the filament wire which creates the heat in the core of the element.  Usually Nickel Chromium, this converts electricirty very efficiently into heat, with only a little wastage as light, as with the filament of an old light bulb.  Whilst it is straight in the picture above (due to being hacksawed), under normal circumstances it would be coiled centrally in the magnesium oxide, as shown below, in this very cool x-ray.

The picture above also helps to explain the terms cold end, cold section, dead length, etc.  The bit before the wiggly filament, that looks a bit like a hose pipe, is the other end of the terminal pin, the nuts & washers electrical connection as described above. Usually mild steel, this section is not going to create a great deal, if any heat, and so this is termed the cold section.  All elements have two terminals, one at either end, to complete an electrical circuit, and both ends will have a cold section of 2 – 6″ dependent on the application.

This length would have to be subtracted from the element length when calculating watts density, ie, a 48″ 1000W element with 6″ colds has only 36″ active length (48″ – 6″ – 6″ = 36″), so the watts density of this element is 1000 / 36 = 28w/in².

So that is a plain heating element, but what about finned heating elements?

Mainly for use in air duct heaters, finned heating elements are merely plain elements as detailed above, but with finning added by a very clever machine.

This allows for better dispersion of the heat, basically by creating more surface area of heated element in the same available space.

Edit – Oct 2021.

There is much debate as to how much finning increases the surface area of the element, thus reducing the watt density, thus allowing you to fit more power into smaller spaces. I am not clever enuf to disprove a claim by one supplier that it increases surface area by 11 times, but in consultations with another friend & supplier, we have come up with a clever possible alternative. A Medical Supplies customer is test driving this idea for us currently, and if successful, will lead to a whole new approach. And probably another blog post for the first time in many a long year.

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