Looking for elegant ways to divert airflow

Question

I am working on capturing air pollution particulate matter from Diesel Generators. Consider the following scenario.

• A 15KVA generator that outlets smoke from the exhaust
• The smoke goes into our capture setup.
• After every 30-40 mins of operation we need to electro-mechanically clean the capture setup. The cleaner assembly takes approx. 60 seconds.
• For that duration we need to re-direct the flow of the exhaust to another outlet with some kind of timing/logic

i.e. The best example is a ‘Y’ configuration attached to the exhaust, where the flue gas will flow only in one exhaust at a time.

For the better understanding I am enlisting the design parameters as follows:

1. Flue gas velocity: 15 m/s
2. Diameter of the pipe at inlet: 4 inches
3. Diameter of the pipe at outlet: 4 inches
4. Operational temperature: 450°C - 500°C

I am looking at a lowcost/robust way to solve this problem :) as we're building this prototype on a budget, hence we want to examine all the options/suggestions that might be suitable in achieving our above goal/purpose.

PS: I've already looked at the standard diverter valves- but they seem to be an overkill/very expensive(like 2500$)/not designed for our application where temp. is high.

Answer 1

Elegant, robust, and low cost don't often occur at the same time ;-) What you are wanting to do is not trivial, especially reliably at high temperature.

I would start with an "automatic butterfly damper". Most the available dampers will be for hvac equipment and it will take two to achieve your diversion functionality, but they are relatively low cost. You will probably need to cool the actuator or increase its distance from the pipe as it will not be rated for the temperatures you are running it at. Here is another damper

You could also look at fabricating a more elegant solution yourself and just source the actuator(s).

A pneumatic conveying diverter valve would likely work well too as they usually handle pretty high heat, but sounds like they would probably not be in your price range.

If the unit can be at the end of the exhaust system and you dont need a perfect seal, you could look at using a linear actuator or two to physically move it away from the end of the exhaust pipe.