fan calculation

The required flow is very small. Trial and error would be the most effective way of accomplishing what you want. Get a little fan from a surplus store, rig it up and measure the flow coming out with an anemometer (which you can rent) if you want to get technical. You should get a fan slightly bigger than what you need and control the flow with a little damper valve.

Good luck

You should look at the maufacturers site - they often have diagrams for rough estimation ( www.papst.de).

Having designed Industrial Convection ovens for the baking industry. I understand your situation. Considering not everyone has CFD software. A lot is by trial and error.

Along with this,since I have design for OEM companies, these companies wanted to get into and diversify into other industries such as the Baking Industries. Usaully because they stumbled on their own with with they had, (actually forced to). And go with the ignorant notion that an conveyorized tunnel oven is just a hot box with a conveyor running through it.

Remember you not only have to design it to perform, also to meet the applied codes, whether its national, state or local.

Another footnote, this is taking from experience. the issues on your oven will arise after its put online and running into production, and it may not be what you expected.

I can assist, I will need more information, to pin down what your are doing. I'll give you some pointers doing the air flow as a guesstimation guideline and should not be too difficult, but it's still a guesstimation. (I think I just stepped into something with that last statement.)

What Needed is;

1.) product and product type (being size/shape).

2.) what your doing to the product (actual finish baking, or just browning/caramelizing) or ?????.

3.) what type of oven. continuous or batch

3.) output. units/hour

4.) Oven size, Width, Speed, Length (foot print)

5.) how its heating. Gas, I.R., ect....

Thing about convection, what you want and what convection does is to break up the boundary layers on the product, because as it's baking, the moisture will create an insulating barrier that will impede heat transfer.

This will get you started.

Excellent list. To simplify, pressure losses will increase with turbulence (which in a convection oven, you want a lot of) and length of travel for the air stream. If you go with trying to solve this with trial and error, make your initial errors on the high side. Throttle back until you reach what you consider to be the best compromise for flow and pressure.

I did forget one thing or point out, which Ried mentioned. error on the conservative side.

After making the guestimation and use that as a reference point. For control I put the fan motors on a frequency drive to pin it down after bringing online.

Not all has freq. drives in thier budget or to justify it.

one more thing, not too conservative. your product might blow away............

I thought I posted this earlier, but maybe not 9or maybe it got deleted by the CR4 police?).

I have a friend that used to build crude calorimeters to measure total heat from the desired cold temperature of product to room temperature. He would use that number and upscale it to the desired production rate to size flash coolers that used liquid gas (CO2, N@, etc.) for freezing food.

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

Build a box from 2" foam, put in 1 or 2 pounds of frozen product, cover it up, and see how long it takes to reach room temperature. That should give you BTU/lb product.

I do have to query your air flow rate. One of the smaller centrif fans available at 100mm dia impellor will deliver 150,000l/h against 200Pa resistance so 100l/h is miniscule. In terms of heat carrying capacity 100l/h with a temperatured difference across the working chamber of 20K is less than 1W. Check your numbers/units.

sorryyyy, it was clear my mistake...100 m3/h (100000 l/h)

Thanks for your kind recommendations

"Oops! DUH."

At least you're honest and admit your typo. I rated you 1 vote for honesty!