controlling the element

cruzan · Post by **cruzan** » Mon Sep 11, 2006 2:14 pm

i making scrambled eggs this morning and it got me thinking about the switches on the oven that control the heat. i tryed looking them up. found out there called an infinite switch or surface burner switch. i cant find any specs on them. could one of these be used to control the amount of heat the element puts out? what are people controlling the heat with, if they even mess with it.

Post by **Tater** » Mon Sep 11, 2006 2:46 pm

Try search feature on this sight. Infinite switch

stoker · Post by **stoker** » Tue Sep 12, 2006 12:56 am

I think if it works for the oven, it should work for your still, at least if the 2 elements are in the same power range.

Post by **Tater** » Tue Sep 12, 2006 6:25 am

stoker wrote:I think if it works for the oven, it should work for your still, at least if the 2 elements are in the same power range.

Hows That Stoker when both types of switches {surface and oven} cycle on and off to heat ?

stoker · Post by **stoker** » Tue Sep 12, 2006 9:05 am

hm, my stupidity

but are you sure it works with a thermostate, rather then a power controller?

Post by **Tater** » Tue Sep 12, 2006 12:22 pm

yep Least ones Ive been working on last 30 years have been

cruzan · Post by **cruzan** » Tue Sep 12, 2006 12:23 pm

thats what i was curious of. if its a thermostat kinda thing or is the switch more like a dimmer

dr wacky · Post by **dr wacky** » Tue Sep 12, 2006 8:54 pm

I've worked in the appliace parts industry for many years. While just about
every oven element I've seen is thermostatically controlled, most electrical
surface unit switches are power controlled. However, any of your nice cheap
snap shaft, universal surface switches are really only a 3 postion switch.
The knob may have a full range of infinte movment, inside the switch you
only have LO-MID-HI (It's also this way on many low end model ranges).
Not really much help if you are trying to acheive a high degree of
temperature control. If you step up to a Kingston-Sealy type switch, you
are getting a 7 to 10 postion switch (depending on make and model). This
allows for a higher degree of heat control, but these switches can run 50$
and up and are getting harder to find (damn electronic controls taking over).

I've seen a nice set up using a standard 110v hot plate set on full, and
plugged into a heavy duty light dimmer. The unit was able to deliver
excellent heat control. Much better than the 5 postion switch that was in
the hot plate.

Post by **theholymackerel** » Wed Sep 13, 2006 6:08 am

This has been said a million times in a million different posts and essays, but here it goes once again.

All ya want heat-wise for yer still is CONSTANT heat. As long as the heat imput to yer still stays the same (no cyclin' on or off, or risin' and lowerin'), yer fine. The temp of the liquid in yer boiler WILL rise with time, as will the vapor. With a pot still ya don't worry about it and you retain control by makin' "cuts". With a column still ya controll yer product by controllin' reflux.

So everyone stop with the faulty thinkin'. DON'T try and controll what's happenin' inside yer still by alterin' the heat added... this will mess everythin' up and give ya a crappy product.

All that must be done heatwise is to maintain' even constant heat through out yer run. If yer runnin' a potstill yer cuts are yer controll, and with a column still yer reflux is yer controll.

cruzan · Post by **cruzan** » Wed Sep 13, 2006 11:29 pm

i know this i was just wanting to run a 3kw element to heat up faster then turn it down to around 1500w but i guess it would be much simpler to have 2 elements or use propane

Hackers · Post by **Hackers** » Thu Sep 14, 2006 2:38 am

[quote="So everyone stop with the faulty thinkin'. DON'T try and controll what's happenin' inside yer still by alterin' the heat added... this will mess everythin' up and give ya a crappy product.
.[/quote]

I'm sorry mate but you are quite wrong.

Maybe you need to try it before you start saying comments like that. In fact you will get just as good a product as without automatic heat control - there is NOTHING DIFFERENT beteween the results produced with automatic heat control and manual control. Just a whole lot less hassle. I always get 92% distillate (assuming I've cleaned my column

) using automatic heat control.

All automatic heat control does is allow you to set and forget, but you are correct in that the most important factor is a constant heat with no surging.

This is why a Triac or PID controller is necessary as they will cycle the heat on and off of one element so that it never overshoots, while the other element does not allow the temperature to drop. In this way the temperature remains constant regardless of the composition of the wash.

rkr · Post by **rkr** » Thu Sep 14, 2006 3:18 am

theholymackerel wrote:This has been said a million times in a million different posts and essays, but here it goes once again.

All ya want heat-wise for yer still is CONSTANT heat. As long as the heat imput to yer still stays the same (no cyclin' on or off, or risin' and lowerin'), yer fine. The temp of the liquid in yer boiler WILL rise with time, as will the vapor. With a pot still ya don't worry about it and you retain control by makin' "cuts". With a column still ya controll yer product by controllin' reflux.

So everyone stop with the faulty thinkin'. DON'T try and controll what's happenin' inside yer still by alterin' the heat added... this will mess everythin' up and give ya a crappy product.

All that must be done heatwise is to maintain' even constant heat through out yer run. If yer runnin' a potstill yer cuts are yer controll, and with a column still yer reflux is yer controll.

Well, whether we want constant heat or not depends on the still head we are using. There's so called power management (PM) principle which is basically a CM still with constant reflux cooling. With such a still we can use power controller for adjustments. With good controller this is actually much more accurate method than trying to controll the reflux ratio with cooling water.

The same principle can be applied to a reflux controll still where we controll the amount of liquid returned to column (overflow is removed as product). If this amount of reflux returned stays constant we can again adjust the system with power controller.

Cheers, Riku