Power control options for a DIY 100-jar Canning trough

Greetings all !

I am new to this community but I hope to find some knowledge in regards to a project I working on.

I am building a custom bit of gear for a small canned Salsa company I am starting up in Canada! The trick to my little business is in the custom canning trough I am building. Essentially it is a bath of boiling water, large enough to submerge 100 mason canning jars.

The water is to be boiled via x4 4500watt 240v elements. These are off-the-shelf hot-water tank elements from Home Depot and should pump in more than enough energy to boil my water... at least as far as my calculations go.



MY QUESTION is this: In what ways could I control the power supplied to the heating elements?


I am currently trying to find variable controls like that found on electric stove ranges but I haven't been able to find schematics for the internal workings of any variable controls...

my requirement is that I am able to maintain boiling water without running the heating elements at 100% all day. Any help is greatly appreciated!

Smile On
-Tyler

Basically, what you need is a control loop consisting of a temperature sensor, a reference level (your desired temperature), a circuit to setect a difference between the two and a power control circuit. A normal cooker control may not be rated for as much current as even one 4.5KW load and in total you have about 75 Amps to switch, that's a considerable amount of current. Again, most cooker controls do not monitor the temperature at all, they are simple timer switches. Inside them is a small bi-metal spring which warms when turned on and operates the switch for a time decided by the knob setting. A low setting means it switches off quicker, high means it's on most of the time, they don't measure anything at all. The few controls that do take a measurement use thermocoupled pressue switches, a small expansion vessel and air tube that rely on expanding air (sometimes a liquid is used) to push a diaphragm which in turn operates a microswitch. No electronics is involved at all.

I would suggst your simplest solution would be to use a one-wire temperature sensor such as the DS18B20, a small microprocessor to tallk to it and read the voltage from your manual control and four triacs, one for each element to actually do the switching. It should be a simple and inexpensive circuit yet give accurate temperature control.

Brian.

Unless you really want to build you own circuit and write your own software I would suggest looking for a "PID Controller" and beefing up the output with additional solid state relays.

Amazon.com: Dual Digital Display PID Temperature Controller. Great for Sous vide: Everything Else

Keith.

A lot of power. You need strong fuses. Guess you have solved how to distribute heat evenly as that else can be a problem.
Do not see any need for continuously variable heating regulation as the system will react slow.
I had built regulation circuit in a box with DIN rails as most of the stuff you need probably is prepared for this.
Connect each heating element to a three phase relay.
In control circuit, add in serial a mechanical overheating fuse or switch for each relay.
Connect each control circuit to a PID regulator type: PID controller.
Let each regulator have its own temperature sensor, which you can buy at same place.
Automatic fuses for each element can be a good idea because if one element becomes shortcut, remaining element can still heat and faulty section is self indicating.
Whole installation must be done in a professional way and with cables and connectors that can survive heat and moisture and is correct dimensioned for actual voltage and current. In some cases can a special isolation and grounding classification be required for the power cables. Check this with local regulation.
Finally let an licensed electrician check all cabling and let him sign that everything is properly done. It can be important for your accident/fire-insurance.