Overfire alarm?

[cbrodsky]

Reading through some recent posts, I see the usual questions about overfiring.

Seems to me that it would be quite inexpensive these days to have a thermocouple driven temperature alarm that would just sit on your stove top. (or clip to your stovepipe) Biggest issue I can see is the electronics/battery overheating, but that could be resolved with a standoff that would keep the electronics off the stove itself where the thermocouple would need to rest. Could further minimize any danger by using a miniature battery.

I would personally find such an item handy for that once or twice a season when I happen to load up a particularly awesome batch of wood and it gets above my normal operating range... maybe even for $50 if it gave me a digital readout as well.

I've seen full-featured units that do all that and much more for $100-$150 that I've thought about buying, but has anyone found something in the $30-$50 range that just diplays temperature, and has an either preset or user selectable alarm? Would there be a market for something like that?

-Colin

 

[webbie]

Years ago there was such a device for 100 or so - they did OK, but not great (marketing wise).....

I think one for less than $40 would fly, and be very possible given improved technology.

But marketing is the key - who will sell them? I showed an invention for pellet stoves at my inventors club last week - and one comment was "stove dealers won't sell it because they don't want to admit the problem (which my invention helps solve) exists". I have to admit they are correct!

So you have to sell them aftermarket.....a dealer does not want to scare a customer.

 

[EatenByLimestone]

There was a big thread on this last year. It got me thinking enough to make a cheap one from a doorbell and a stovepipe temperature gauge. I used the temp gauge indicator for the switch.

The main problem I see here is it would create one hell of a liability. If you buy it, you are going to rely on it. What if it didn't work? What if a child died in a fire where one of these was attached to the stove? I can't imagine the liability smoke alarm companies have just incase on of their devices fail.

Matt

 

[babalu87]

I have one.
I loaded the stove the first season with some petrified oak that was dead, down but not on the ground. I dont know how long it was there but it was dry and hard as a rock, burned great. Problem was a full firebox caused a bit of an issue. I normally run the stove pipe from 300-450+ and touch 550 from time to time. Well, after putting a FULL load of this petrified wood in and getting it going the wife and I go to bed. An hour later the alarm at the bottom of the stairs goes off and I run down to see the stove pipe at 650 and climbing. I shut the damper down all the way and it slowly subsided back to 500.
That fire alarm at the bottom of the stairs is pretty sensitive and all that hot air rushing up the stairs set if off.

 

[kwburn]

I'm sure it can be done at that price. They sell cooking thermometers (maybe $25) made for meat that have a digital readout unit that sits outside the stove and a temp probe at the end of a heat-proof wire that goes into the stove. You can set an alarm to go off at a wide range of temperatures. I have one and actually messed around with it sticking the probe into the air outlet on my insert. If they make one with a probe I can't see why they can't make one with a magnetic temperature pickup that can just stick to the outside of the stove. But of course its all supply and demand, can the manufacturer get enough sales to justify designing it?

Something else I have is one of those digital weather thermometers with the wireless pickups you can place anywhere (designed to put outside to give outside temperature). I keep the base in the room where my stove is and the wireless sensor upstairs in our bedroom to give me an idea of whether the stove heat is making it upstairs or not. Anyway, on the base you can set an alarm to go off whenever you reach a certain high or low temperature (either in the room where the base is or where the wireles sensor is). This is not an expensive unit, maybe $20. It's not going to prevent overfires, but maybe with some imagination it could give a warning just like the person who's fire sensor went off.

 

[Gooserider]

Trouble with both the meat thermometers and the weather stations is that they temperature ranges they work at are to low for the temps on a wood stove, at least the points that are normally monitored.

Gooserider

 

[cbrodsky]

Trouble with both the meat thermometers and the weather stations is that they temperature ranges they work at are to low for the temps on a wood stove, at least the points that are normally monitored.

Gooserider

Yep, that's the issue I found as well - you really need a thermocouple probe, and they almost universally support way more functions than you really need, making them in the $100+ range.

I'm sure you could hardware something with limited functionality for a lot less, but then liability, etc... and other good topics brought up show this wouldn't be trivial.

-Colin

 

[begreen]

I actually started designing one of these last year. My thought was to make it a digital probe thermometer and have a small a thermoelectric module power it. The user should be able to set the alarm temp point. Above 900 degrees it would flash the display and beep steadily. I was hoping to have a form factor (round dial with digital readout) similarly sized to a current probe thermometer. The electronics would need heat shielding + heat sink it this was to magnetically attach to the stack. And the digits should be readable across the room (maybe 1/4" high?).

 

[Gooserider]

I actually started designing one of these last year. My thought was to make it a digital probe thermometer and have a small a thermoelectric module power it. The user should be able to set the alarm temp point. Above 900 degrees it would flash the display and beep steadily. I was hoping to have a form factor (round dial with digital readout) similarly sized to a current probe thermometer. The electronics would need heat shielding + heat sink it this was to magnetically attach to the stack. And the digits should be readable across the room (maybe 1/4" high?).

I would say make the digits more like 1/2 - 3/4" high for those of us that don't have the old "eagle eye" any longer...

Gooserider

 

[webbie]

I think wireless or optionally wireless would be the ticket - maybe bluetooth would do. This stuff (the guts) have really come down in price.

Isn't a "thermistor" simply two piece of wire twisted together? I have a digital temp meter that goes up to 2000 F and all it has is that - two pieces of wire twisted together.

The unit would either have to have a remote readout or else be designed with decent looks since most are going into the living area. It might be that some car electronics (sensors), which are obviously made in vast quantities, would do the job. Also, I assume regular gas and electric ovens have high temp electronics in them, because the cleaning cycles can hit 800 degrees.

I can see it now - we're each going to be able to monitor each other's stoves over the net!

Speaking of that - why doesn't someone here start the first "stovecam" - someone who burns 24/7 and has broadband could buy one of those little internet cameras (no computer needed) which has a built-in IP. Then we can broadcast the pics to a server (hearth.com) - and we can link to them.

If we can find the right candidate, I would chip in for the camera and provide the server space. I think we would be the first to do exactly that with a webcam!

 

[BrotherBart]

If we can find the right candidate, I would chip in for the camera and provide the server space. I think we would be the first to do exactly that with a webcam!

Like the original. The fish tank at Netscape. Saw the thing when I was in a meeting with them back in the day.

 

[webbie]

There was a coffee pot at a university in UK which was one of the first ones I saw!

http://en.wikipedia.org/wiki/Trojan_room_coffee_pot

 

[kwburn]

Trouble with both the meat thermometers and the weather stations is that they temperature ranges they work at are to low for the temps on a wood stove, at least the points that are normally monitored.

Gooserider

yeah i checked my digital meat thermometer gizmo today and it only goes up to 450 degrees. since i was using it only to monitor the hot air blowing out of my stove it worked in that short lived task.

stove web cam would be great. can you imagine if we had one with some scantily clad young lady that comes to load it every few hours? you could sell advertising on that one!