Home Made Venturi Smoke Generators
Home made smoke generators are easy to build from ready to make components which are available from Home Depot. To our surprise it has performed incredibly well and it was very easy to make.
The system consists of three parts:
- Air pump, connecting tubing and an air injecting nozzle.
- Smokebox - a container where wood burns and and smoke is produced.
- A pipe that connects smoke box with a smokehouse. A nozzle that injects air may be located inside of the connecting pipe or inside of the firebox.
The air pump can have a fixed air pressure output or it can have an adjustable volume control. An adjustable volume air pump permits to control the amount of smoke that is generated. In most cases a small 3.5 W adjustable air pump is all that is needed. Do not expect much air pressure coming out from a typical air pump. It is hardly noticeable, but surprisingly it is all that is needed to do the job. A higher pressure adjustable air pump (4.5 W, 4 psi) can be used for making a higher output smoke generator.
Decreasing nozzle diameter should theoretically increase the air speed and induce a stronger vacuum. However, in our tests we did not observe any significant difference, most likely due to very low air pressure that the air pump supplies. In our opinion the extra work involved in decreasing the diameter of the nozzle is hardly worth an effort.
This can be any type of a metal box or a pipe. They range from 2.5” (64 mm) diameter and up. If you make it yourself our recommendation is to go with 3.5” (89 mm). This diameter allows insertion of a hand inside in case some assembly is required. A metal container can be assembled from thin metal sheets, corner brackets, little bolts and nuts. Those fireboxes usually average about 6-10“ (15-25 cm) in height.
We made our own box, but it was time consuming. A better solution is to visit a local machine shop. They will have round tubes, square tubes and they can cut, drill, and weld them the way you like. You can also look around for a suitable container, even a large metal can will do the job. What may change is the way the connecting pipe and nozzle are secured.
By flipping the smoke box 180° , the design changes from low to high nozzle configuration. Of course, you can make a fixed high nozzle generator.
Venturi smoke generators are small units and can get easily dirty. It is recommended to clean them well after each use. Those units can be used outdoors as well as there are many inexpensive battery operated aquarium air pumps. They usually operate on two D size batteries and last up to 48 hours.