Heating element project

[Tex N Oz]

I've noticed a trend on the forum with heating elements. There seems to be a lot of trouble with them.

I've taken up the task of designing a Triclover style heating element that will hopefully over-come all these issues.
The design is quite simple and must fulfil the following (with explanations to the side).

1. Must be 100% hermetically sealed with electrical connections encapsulated. Not just the element area, but the entire element all the way to the end of the cable.
   This will allow the operator to place the element straight into a vat without having external access ports for the element, greatly increasing versatility and the ability to heat in just about any vessel.
   
2. Element surface must be copper. The stainless steel elements on the market today are either prone to hot-spots because stainless doesn't like to conduct heat, or they're high in nickel. While not trying to start a debate on the safety of nickel, there's a very good reason you don't see nickel cookware. It seems that once you put it in a matrix that makes it safe, the HEX rate goes down. I'm going to make it simple and just go with the gold standard... copper..
   I'm not sure how this would go boiling wort at lower ph, but I use gas for the boil and this is just for strike water and HERMS. Maybe someone could chimb in with some additional information. I have however seen a number of copper boil kettles in breweries.
   
3. Element must be made either in Australia, USA or Germany. These 3 make good elements. China land elements are notorious for burning out for no reason other than hotspots in the element resistive core. A ruptured element releases toxic materials into whatever it's heating. There's a good reason that your hot-water heater is still churning hot water 24/7/365 for years and years later.
   
4. Element must be 100% earthed and the power supply must be RCD protected. This is for safety of the operator should something catastrophically fail.
   You can always buy new shit but you can't undo electrocution.
   
5. Wiring cable must be able to withstand wet, heat and mechanical stress while in operation. This posses it's own set of problems as the cable is more expensive than just about anything else in the system. But I'm after quality, not cheap.
   
6. No mechanical only electrical connections. All electrical connections must be fusion bonded plus mechanical. Heating and cooling of mechanical connections is #1 cause of failure in well made elements.

Here's the element that I'm going to use for this build.



Here's the frame that I've removed the element from. Note the extremely small element grounding wire. The new build will have a very heavy bonded ground.

 

[MHB]

You have totally missed what is for me the most important feature of element selection (well second - safety first)
Heat density, nearly all elements people use get too hot on the surface this caused scorching of the wort, kills enzymes near the element and dramatically reduces the element life.
If you want to see what immersion elements should look like go have a gander at a Braumeister, I know people whinge about the price - but when you buy German engineering you tend to pay a bit extra and get the best quality. There is a dam good reason the elements in Braumeisters are very long.
If you fill up a Braumeister with cold water, you can hold the element in your fingers until the water is too hot to have your hand in, might give you some idea of what we mean by Low Density Element!

I am mucking around with a small (10L) system just for tinkering with, I am thinking of mounting the element outside the Mash Tun/Kettle and letting the heat travel through the entire base of the kettle (Al sandwich) just like a stockpot on a stove.

Other than that yes - I like most of your thinking re elements, I have been looking at some of the Air Heating elements used in things like tumble dryers - long low density elements and not ridiculously expensive.
Mark

 

[Tex N Oz]

I've taken a 63mm sanitary cover and bored a 38mm hole through the centre of it.

Left is the bored one and the right is one before it's bored.



I've then cut a 40mm long piece of 51mm stainless and welded it onto the bored out cover to make this.



Here you can see how the element fits inside the assembly. The element has to be fused into the assembly and I will do that with silicone bronze, but not just yet. It's important to have all the wiring connections completed before I complete the assembly.



Note the blue/golden colour on the face of the cover. That's because I've not "pickled" that part yet. Once it's pickled, passivated and polished, it will be like a shiny new dollar.... I think that's a yankee term...

 

[Tex N Oz]

You have totally missed what is for me the most important feature of element selection (well second - safety first)
Heat density, nearly all elements people use get too hot on the surface this caused scorching of the wort, kills enzymes near the element and dramatically reduces the element life.
If you want to see what immersion elements should look like go have a gander at a Braumeister, I know people whinge about the price - but when you buy German engineering you tend to pay a bit extra and get the best quality. There is a dam good reason the elements in Braumeisters are very long.
If you fill up a Braumeister with cold water, you can hold the element in your fingers until the water is too hot to have your hand in, might give you some idea of what we mean by Low Density Element!

I am mucking around with a small (10L) system just for tinkering with, I am thinking of mounting the element outside the Mash Tun/Kettle and letting the heat travel through the entire base of the kettle (Al sandwich) just like a stockpot on a stove.

Other than that yes - I like most of your thinking re elements, I have been looking at some of the Air Heating elements used in things like tumble dryers - long low density elements and not ridiculously expensive.
Mark

I wholly agree with what you are saying. Heat density is a huge factor in systems without medium. In a HERMS system it's not so important but in a RIMS or direct heating system it is.
Part of my build, not related to the element, is a phase shifting controller to wind the element output down to a very low wattage if needed. I intend to use this element for heating large sous vide vats that are made from PET plastic with the element sitting in a small cage with water flow. I don't want my element to get too hot and if I wind it down from 3.6kW to 200 or 300 Watts, there's almost no chance of over-heating to melt plastic.

You must be very careful in selecting air heating elements for use in a liquid. These elements are usually not hermetic and can short out. I've had similar problems installing heating elements too close to cold vapour humidifiers in industrial A/C equipment. As for aluminium encapsulation, that's a bit of science I once tried that was a morbid failure. When you clad, you must use special dopants on your stainless and in an oxygen free environment or the metals de-laminate on first heating. I have considered casting a whole element in copper though.. That might be my next big project.

 

[sp0rk]

1. Element must be made either in Australia, USA or Germany. These 3 make good elements. China land elements are notorious for burning out for no reason other than hotspots in the element resistive core. A ruptured element releases toxic materials into whatever it's heating. There's a good reason that your hot-water heater is still churning hot water 24/7/365 for years and years later.

That's not usually why they're prone to burning out
As someone who used to design heating elements, the main reasons I encountered with burnt out elements are;
Dry heating liquid immersion elements, user failure
Moisture ingress in an unsealed element, leads to a short between the internal spiral and the outer sheath (we filled our elements with magnesium oxide, it likes to soak up moisture)
Poor spiral winding, THIS is the main cause of hotspots, I don't believe we ever had this happen with the company I worked for
Poor spiral placement, the spiral isn't placed centrally in the sheath during filling and it shorts to the edge if/when it shifts for some reason
Element bent in too tight of a radius, the spiral shifts during bending and shorts on the sheath
Too high of a watt density for the application, solids burn onto the element and create hot spots which then overload
Element made of incorrect sheath material for the purpose, acidic conditions wear away the sheath too quickly and moisture ingresses, 316 Stainless or Incoloy 800 are perfect for brewing applications

Thermal Electric Elements (quite expensive, but very good elements) or Romar are 2 Aussie producers that would be able to sort you out
5 Star Distilling's elements while made in China are VERY well designed, ultra low watt density and completely sealed if you use their enclosures
There are plenty of choices already out there perfectly suited to our homebrew applications

 

[MHB]

You must be very careful in selecting air heating elements for use in a liquid. These elements are usually not hermetic and can short out.

Too true, I wasn't suggesting putting dryer elements in water, more a case of spreading the heat all over the base of a pot from the outside.
M

 

[MHB]

Snip
Thermal Electric Elements (quite expensive, but very good elements) or Romar are 2 Aussie producers that would be able to sort you out
5 Star Distilling's elements while made in China are VERY well designed, ultra low watt density and completely sealed if you use their enclosures
There are plenty of choices already out there perfectly suited to our homebrew applications

I wouldn't regard the 5 star as Ultra Low Density, again have a look at what is in a Braumeister, the 2000(ish) W element is several meters long, the 50L model has two elements.
We area talking an order of magnitude longer and lower density than most of what we see in home made versions, there are really good reasons for doing this.

 

[booargy]

My RIMS element is 6kw, 8mm in diameter and 6m long. When elements are called low, ultra low it is just a sales gimmick

 

[sp0rk]

I wouldn't regard the 5 star as Ultra Low Density, again have a look at what is in a Braumeister, the 2000(ish) W element is several meters long, the 50L model has two elements.
We area talking an order of magnitude longer and lower density than most of what we see in home made versions, there are really good reasons for doing this.

Sorry I should have specified which, the weldless element is more low watt
However I'd rate their screw in at Ultra Low http://www.5stardistilling.net/2400w-heating-element/
If I remember correctly ULWD elements are usually below 50W/in2
The 5 star screw in element has 2 loops each at around about half a meter total sheath length per loop
a very quick guesstimate puts them somewhere around 40W /in2
They'd be higher than the Brau element, but still within acceptable limits

 

[MHB]

My RIMS element is 6kw, 8mm in diameter and 6m long. When elements are called low, ultra low it is just a sales gimmick

If you were right I would agree with you!

Sorry I should have specified which, the weldless element is more low watt
However I'd rate their screw in at Ultra Low http://www.5stardistilling.net/2400w-heating-element/
If I remember correctly ULWD elements are usually below 50W/in2
The 5 star screw in element has 2 loops each at around about half a meter total sheath length per loop
a very quick guesstimate puts them somewhere around 40W /in2
They'd be higher than the Brau element, but still within acceptable limits

The rule of thumb I have always used is Under 50 is low, under 30 to be called ultra low.
Mind you to get 40 for a reasonable price is good news.
Mark

 

[booargy]

Haha so I was wrong. I thought they were just made for purpose. I have the 20l braumeister the element is about 2.5m long. These are my rims element they are designed to heat oil.

 

[spog]

2.5 metres long ? a typo , surely you mean 250 mm long.

 

[sp0rk]

The Brau element is what he's referring to, I believe
it winds around in the base of the unit a few times, it's a rather long element

 

[husky]

I had a company called Magawatt in SE Vic make up some replacement keg king elements to replace some that went bang. I had a tri clamp blank welded on as the process connection and they have a much better cable and seal than the dodgy KK ones. 316 S/S sheath too but much more expensive than the chinese versions. Designed them to be 70Kw/m2 which I thought was a relatively low power density. I have been using these in the KLT and RIMS with no issue.

Also had some coiled 5kw elements made by the same guys with a 50kw/m2 power density in the kettle, Highly recommended.

 

[Tex N Oz]

That's not usually why they're prone to burning out
As someone who used to design heating elements, the main reasons I encountered with burnt out elements are;
Dry heating liquid immersion elements, user failure

Well, I've had 3 burn holes in the sides before tripping the RCD which indicates otherwise. Side blown out. Never dry-run.
Had it been a short to ground the RCD would have tripped about 10,000,000 joules before catastrophe.
It's MY opinion that the reason these cheap elements burn out so quickly is they are critically designed for 220V and when taken 10% over-voltage they shit the bed.
I still maintain that the reason for the failures I've observed were stress fractures in the resistive core of the elements.

Moisture ingress in an unsealed element, leads to a short between the internal spiral and the outer sheath (we filled our elements with magnesium oxide, it likes to soak up moisture)
Poor spiral winding, THIS is the main cause of hotspots, I don't believe we ever had this happen with the company I worked for
Poor spiral placement, the spiral isn't placed centrally in the sheath during filling and it shorts to the edge if/when it shifts for some reason
Element bent in too tight of a radius, the spiral shifts during bending and shorts on the sheath

Again, I know of no one who doesn't have an RCD inline with their gear. Anyone who doesn't should invest a few quid and get one.

Too high of a watt density for the application, solids burn onto the element and create hot spots which then overload
Element made of incorrect sheath material for the purpose, acidic conditions wear away the sheath too quickly and moisture ingresses, 316 Stainless or Incoloy 800 are perfect for brewing applications

Thermal Electric Elements (quite expensive, but very good elements) or Romar are 2 Aussie producers that would be able to sort you out
5 Star Distilling's elements while made in China are VERY well designed, ultra low watt density and completely sealed if you use their enclosures
There are plenty of choices already out there perfectly suited to our homebrew applications

I'd say that too high of a Watt density for the element design is probably the most likely culprit. That coupled with fractured kanthal or nichrome.

It's too bad Romar is the only company that still makes their own elements. Rheem used to make theirs here but they've moved all manufacturing back to the US.
Unfortunately we've voted ourselves such great awards that all jobs are moving off-shore. Those that are hanging on charge like a wounded bull to keep afloat.

However, with all of that said, my application is absolutely not dependant on low Watt density. No part of this element will ever touch any part of any product. This is strictly for heating water.
How this thread got turned around to ULWD heating is beyond.me.

 

[MHB]

Well if you had said HERMS rather than RIMS, I for one would have been a lot less concerned - the idea of sticking 25 Amps worth of heater into a wort sort of worried me.
Mark

 

[Tex N Oz]

Well if you had said HERMS rather than RIMS, I for one would have been a lot less concerned - the idea of sticking 25 Amps worth of heater into a wort sort of worried me.
Mark

Fair enough.. I didn't realise I had made that reference. Hhhmm.. reading my post sounded like I was chastising but that wasn't my intention. I need to use more emoticons.
The goal of this build is to make an element that can be completely submerged, cable and all, into a boiling liquid.
I did try to find one but couldn't without spending upwards of $2k. I finally found the cable and glands fittings that are autoclave compatible, highly mechanical resistant and can handle the 15 Amps at 180°C. For me it will be very useful when I sous vide 50kg of steaks, chicken breasts or any time I want to heat a large vat of water that doesn't have a built in element. For critical applications that I want to lower the surface temperature I can dial back the output eg, plastic vats or smaller volume vessels. Quite specialised and it works great in the side of a HERMS too. The $$ I'm sticking into this, I don't want a cheap element as even an expensive one will be the cheapest component. I'm building this one with Rheem as I'm familiar with their elements and they've never let me down.

 

[sp0rk]

It's too bad Romar is the only company that still makes their own elements. Rheem used to make theirs here but they've moved all manufacturing back to the US.
Unfortunately we've voted ourselves such great awards that all jobs are moving off-shore. Those that are hanging on charge like a wounded bull to keep afloat.

Romar isn't the only one, Thermal Electric Elements make their own in Coffs Harbour (Toormina to be precise), but they're quite expensive
However they're pretty popular with micro breweries, I know of a few using their elements, Black Duck being one off the top of my head
TEE make a spa heater that might actually work really well for your application
BJC and Argus are 2 NZ manufacturers as well

 

[Tex N Oz]

Capping weld done on the body assembly. What a freakin messy work workspace!!! Clutter is my Achilles heal and I never realise it's getting bad until my blood pressure is up.
Doesn't help that I'm having to do all of my work on the back veranda as my workshop is full of woodworking tools for the renovation.



Nothing makes the missus happier than me slopping pickling gel all over the stainless kitchen sink!! Doesn't matter as the sink is part of the reno.
You wanna be sure to wear a face mask when working with that shit.. Full of nitric and hydrofluoric acid

 

[Ducatiboy stu]

Romar isn't the only one, Thermal Electric Elements make their own in Coffs Harbour (Toormina to be precise), but they're quite expensive
However they're pretty popular with micro breweries, I know of a few using their elements, Black Duck being one off the top of my head
TEE make a spa heater that might actually work really well for your application
BJC and Argus are 2 NZ manufacturers as well

I have done work for TEE in Coffs and been thru the factory

Very high quality and they specialise in doing custom designs.

They are expensive but there failure rate is nearly non existent

No affiliation ..etc..etc

http://thermalelectric.com.au/