Water Clock, RMHFeed Belt – pellets, chips,chunks... Uses weighted rope, pulley, slide --- I changed the title to reflect where this one is headed. It's now about numerous autofeed methods and not just the water clock.
This is another marvel of engineering that currently resides only within my brain and on this site.
The internet is full of expensive electrical belt systems and controls that could accomplish this.
My idea involves using either a belt or a sliding push rod and tray to advance material to the drop zone in a controlled manner. Two ropes are attached to the push rod or belt. The rope attached to one end of the belt is tied to a full water container with a spigot on the bottom. The other end of the rope which pulls the belt toward the drop zone has weights attached in say 4 inch intervals. The total weight of all of these weights is equal to the weight of the full water container. All starts out with the container resting on the floor. After the belt or tray is loaded with wood, the spigot is opened. As water leaves the container, it becomes lighter and at a certain point it's light enough that the weighted rope drops one notch, thus advancing the belt toward the slide by four inches. A small quantity of wood is dumped into the tube and is directed to the fire box. As water continues to leave the vessel, the process continues until the last weight rests on the floor and the water container has reached the upper pulley. The water runs through a tube, into a lower container. I suppose it could just drop in an open stream if you like the sound of a waterfall. This system allows for two means of controlling the feed rate.
1. The spigot could be set so that the belt advances at a given speed say one notch every 1 to 5 minutes according to the flow rate chosen.
2. The belt can be loaded with varying quantities of wood per foot of belt.
Sample feed rate.
Suppose we set the system to advance one notch(4 inches) every 5 minutes and the belt is loaded at a rate of 3 pounds of material per foot which is one pound of wood per belt advancement. The fire would receive one pound of wood every 5 minutes which is 12 pounds per hour. Both rate of belt advancement and quantity of material on the belt are adjustable. This same contraption could feed the fire at 5 pounds or 50 pounds per hour. Belt systems can be made with very little friction. A tray and push rod where material is slid to the drop zone would need to be weighted to allow for friction. Some slope would help.
A system that is 4 feet tall would have a useful belt advancement length of about 3 feet(subtract the container height and the weights will form a raised pile) which equals 9 belt advancements. If set to move every 5 minutes, it would drop the last load of chips 45 minutes from when the spigot is opened. If set on a 2 minute feed interval, it would stop after 18 minutes.
I'll soon submit a drawing, unless some artistic person wants to do it . Although the explanation is wordy, the system is simple and could be reasonably attractive. I don't suppose that these will find their way into every living room. This sort of thing could fit into a greenhouse situation where height of the pulleys would be limited only by ceiling height. This could allow for 10 feet of belt run and 50 pounds of chip feed per hour. A brightly coloured 5 gallon bucket could serve as the water vessel. Workers would always know approximately how much wood is left on the belt by how far the bucket has risen. It could even activate a bell or buzzer.
The same system could be used as an automatic feed for an outdoor hot tub or water heater. It would take just about as long to build this the height of a sawhorse for a little system in the living room as it would to make a good sized one to feed a hot tub. Your wife will love the one that feeds the hot tub. The same may not be true for one inside the house.
Now I have to learn how to draw. --- I watched lots of Wile E. Coyote cartoons when I was a kid. The picture of the chip feeder in my mind looks like something straight from the ACME catalogue. ---------------------------------------------------------------------------------------------------------------------
For the less adventurous check this out --- http://www.qcindustries.com/miniature-conveyor/ Small conveyor systems suitable to the purpose already exist and some run on 12 volts. These could be put on a timer and geared so that a motor the size of your thumb could move 30lb of fuel an inch at a time. Factories are always retooling. An industrial auction might turn up a good deal.
The vibratory feed tray on a timer is next. It's a far simpler item that already exists. Check out --- http://www.youtube.com/watch?v=h8Wt8-xk_e4 An electric drill with a little weight taped to it will vibrate. bolt the drill to any trough and you have a vibrator. Plug that drill into a timer and you have an automated RMH feeding device. These things can deliver fairly accurate batches. Foods like chips and smarties sometimes employ vibratory conveyors in the packaging process.
There is another simple, low tech method of feeding the fire. Produce a child, and have them do it. You'll need to plan things about 5 years in advance. But many of us have already done this so it's a simple matter then. Take the child aside, look them square in the face and tell them that if they ever want to see a T.V. or computer screen ever again, that fire better not go out. This is a rather high maintenance choice so best to use this only if you already have one lying around.
Thank you: Dale Hodgins --- Inventor and tinkerer.
Augers are great for sawdust but must be fairly powerful to move chips since they often get between the auger and casing. One set in an open trough with a floating end could move aside when a clog occurs. A rubber mounting on the drive end might also help on moving the auger. Still some uniformity of material would be required. For pellets, I wouldn't monkey with other methods since augers designed for that purpose are readily available.
I like belts since they are equally serviceable to move a wide array of shapes and sizes, from big lumps to dust. --------------------------------------------------------------------------------------------------------
INVENTIONS 3 AND 4 and maybe more before this thing is done...
Here's a belt based on the grandfather clock drive --- A very slippery trough is built and placed on a slight slope to reduce the power required to slide material. A length of slippery fabric fits the trough with a slight gap along the edges. It could be rubberized on the upper surface which meets the wood. A roller is mounted beneath the lip of the lower end which is the direction that we're moving the fuel. I suspect that the clock is meant for only one speed, so the quantity of wood per foot of belt is our only way of altering feed rate.
This contraption sounds like another that could use a little 12 volt motor with a gear box and timer. Done properly, it should consume very little power. I have a fairly big radio controlled helicopter that stays aloft for 5 minutes using a small rechargeable battery a little bigger than my thumb. That's enough power to run the belt feeder for weeks on a single charge. Batteries are under $20, so it's all about gearing. The shops that sell this sort of thing have little motors and pulleys in a variety of sizes. With a 20 to 1 gear reduction, the little motor can really pull. So then it 's all about the timer. Something like this could have a very slim profile and would not make much noise. I want one.
In another thread, I suggest feeding wood gas from a charcoal retort into the mouth of a RMH. This is not something I'd try inside a house for safety reasons, but it could work in the greenhouse or for an outdoor hot tub or water heating application. The idea is to clean up the dirty business of making charcoal and biochar while utilizing the wood gas. Check out --- Charcoal/Bio-char Production – Utilizing the volatile gasses, reducing pollution and fire risk --- https://permies.com/t/19523/stoves/Charcoal-Bio-char-Production-Utilizing
Any vibratory feeder for chips, nut hulls or other granular materials could benefit from a well designed hopper. By using a hopper, we can have a large quantity of fuel on hand without having to construct a long tray or slide. This video starts off slow but covers quite a bit concerning flow rates and clog prevention. The same 12 volt motor and timer could power a small one for feeding the RMH. Here's the video -- http://www.youtube.com/watch?feature=endscreen&v=YnZnJ_u3u5w&NR=1
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