Part Drying
Part Drying
(OP)
I am currently working on a project where I have to dry parts in a certain amount of time. Currently there are a continuous line of stainless steel fine mesh buckets filled with stainless steel parts being conveyed through a bath of water. The parts and bucket will be around 175 degrees F when coming out of the bath and there will be a bucket with parts following every 20 seconds. At this point I have 19 feet of conveyor, traveling at 6.5 feet per minute, to completely dry the bucket and parts. The first 5 feet will be open to the atmosphere in the shop. The next 12 feet will be in an enclosed shell. The shell will have 14.4 kw worth of heating elements (can add more) and insulation around the whole shell. The elements can go up to 950 degrees F, but we do not want to have the temperature high enough to heat treat the parts because they will already have gone through the heat treating process. The enclosed shell is the only control area, and I need help figuring out what to do to evaporate all the water off of the bucket and parts. The next 2 feet will be open to the atmosphere in the shop. The buckets will be coming out of the bath every 20 seconds.
Thank you,
simoncad
Thank you,
simoncad





RE: Part Drying
I would have thought you'd want a curtain wall of air first to blow off most of the water
TTFN
RE: Part Drying
RE: Part Drying
Then, you need to figure out how much water is left. Is it just a surface film, or do the parts have cavities that could contain significant amounts of water?
RE: Part Drying
12 feet of drier length, 6.5 ft/min. Each bucket is in the tunnel for 1.8 minutes. Lets call it 2 minutes.
Bucket every 20 seconds, means 5.5 buckets in the tunnel at any given time.
5.5 buckets * 1.5 pounds of water in each = 8.3 pounds.
37 degree sensible rise at 1 BTU/degree. 970 BTU/pound latent. You'll need to put 8,400 BTU into every 5.5 buckets to evaporate the water.
2 minute dwell is 1/30 of an hour.
8,400 / 1/30 = 250,750 BTU/hr, or 73 kW.
This is for the water only, you also have to heat up the parts and the buckets.
Your 14.1 kW isn't going to cut it.
RE: Part Drying
Can't you use buckets with holes?
If the bucket is just to serve as storage to put parts you might want to make it as open as possible exactly to have the water drained. This will be much more economical than evaporate all the water.
RE: Part Drying
Patricia Lougheed
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RE: Part Drying
RE: Part Drying
Mint, I was trying the same thing before I read your post. Counting the parts and buckets you may need 120-150kW.
The real key is air ciculation. Unless you have a lot of air at low relitive humidity you will not get anything dry.
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RE: Part Drying
i just received updated information about the process
it turns out that when the buckets are in the bath they are moving at a speed of 4 fpm. 16 inches or 20 seconds apart. when we get them on our conveyor we can slow down to 3 fpm and have the buckets 12 inches apart. this will allow for 4 minutes through the shell. our shell will have fans blowing through the heating elements. this will supply hot dry air to the buckets. we just need some to devise a way to get the humid air out. i also need to figure out exactly how much kw is sufficient.