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plumbing help!

So, we have made and tried our bath pasteuriser....and it does work...however, its taking an age to heat up so we need to look at something to make it heat faster.
Is anyone here either a plumber or heating engineer type person?
The water needs to come up to 70 degrees and the volume of the total water is 90 litres (this includes the cider in the bottles and the water surrounding the bottles. The elements sit under a metal mesh shelf which the water circulates through. The bottles sit on top of the shelf.

At this time the heating is done by 2 X 3kw elements.

So - we could replace these with 2 4kw elements
fill the tank from hot water outside the tank (ie water heater or other) OR

any other ideas?

We have now been categorically told that the 3kw elements arent the issue - that they should, in fact be heating the water in 60 mins.
John has also been told to go and check the wiring to ensure they have been wired seperately and not in tandem as this may be the problem....
so looks like an electrical/circuit issue....

ignoring energy in for a mo ,is the thing well insulated ie is the tank lagged with a suitable material and does it have a lid to prevent heat loss?

yes, fully insulated - walls, bottom & lid. (keeps warm overnight with no power).
Getting someone locally who is a good electrician is proving difficult. I have spoken to Vigo re a spare element (9kw) but its not going to fit our tank.

Ive asked John to draw out a wiring diagram.....

ok ......

warmish water in from a hot tap might help

as might a heat exchange coil from a boiler

100 kg or so of "water" and glass does need quite an input to heat it from say 10 c to 70c ,it might be that the elements you are using are not enough to do it quickly

iirc a 100 lt/kg immersion heater takes a couple of hours with a standard element to get it to a bit above bath heat so to get that mass to 70c might take a bit longer

Well, that been another day of fun and shouting at this house.....

Lets just say the elements in the pasteuriser just arnt doing what they need to....

After clamp testing them they are 19 ohms which is right, but he has wired each one individually to the power via a 16amp plug and they are barely heating, so we know that we need to change the elements....

Can anyone help?

Well, after stomping off to the shed, he has removed the elements to find that they are 500watt, not the 3kw we ordered, so an email has been sent to the company.
Hopefully, they will restitute this and send the real ones!
What a lot of wasted time!

that would be the problem 1kw isnt much more than a fish tank warmer in a thing of that heat capacity.

i was about to suggest the element from a "tea urn" type thing or a pair of 10 kw kettle elements and a stirrer paddle

thinking about it a small stirrer might help a lot in any sort of waterbath ,especially if every bottle has to be gnt to have reached temp for a given time and none need cooking.

a small motor ,a bit of stainless steel bar with a propeller, a clamp,job done

trusting convection to even the temp throughout the batch could be quite a risk

With the bottles in will you get much flow using a stirrer?

Might be better to use a central heating pump to move the water from one end to the other.

With the bottles in will you get much flow using a stirrer?

Might be better to use a central heating pump to move the water from one end to the other.

No. Pumping would be far better.

they are probably correct about a pump.

intake high/outlet low at opposite ends might work .
Mistress Rose

The water baths we used at college to keep things the same temperature for long periods had pumps as I recall. They also had plastic balls on the top to keep the water from evaporating.

No pump required - none of the commercial ones even have this.
There is no room really anyway.
Ive spoken to a company that make elements and am waiting (always waiting) for a quote on Monday.
According to them( and the industry) 2 X3KW should heat 90litres in just over an hour which is fast enough.

Then just pop some thermometers around to make sure you have an even temperature spread. If you've packed it with bottles, you run the risk of uneven temperatures, and failed pasteurisation, with all associated issues.

There's room for a pump. It doesn't have to be internal, just a pipe in and out.

The elements. Can you just use immersion heaters?

I have thermometers and sensors at both ends and thermometers in the bottles spaced around....
Speaking to the element guy tomorrow....

i woke up and thought i should mention a residual current circuit breaker ,mains electric and water can be nasty.

got it! Its fine - Im a safety freak....
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