ACFM or SCFM
ACFM or SCFM
(OP)
Hi All,
I am trying to figure out the problem on our Tunnel oven supplied three years ago to our customer.
Recently, we found that the Water is coming of the Tunnel Oven through Gaps of Each Modules.
I am being asked to verify/check the Exhaust fan CFM rating of existing fans. whether these fans are unable to remove moisture from the oven or not.
I have calculated the Actual CFM ( ACFM) considering all the process involved in the tunnel oven
We have 6 exhaust fans on the oven with 1100 CFM(SCFM)(Existing) Rating each.
Now I need to check & compare whether Fan CFM rating is ok or not.
Do we need to consider ACFM or SCFM for Exhaust fan selection. Pl. Help.
Thanks in Advance.
Som
I am trying to figure out the problem on our Tunnel oven supplied three years ago to our customer.
Recently, we found that the Water is coming of the Tunnel Oven through Gaps of Each Modules.
I am being asked to verify/check the Exhaust fan CFM rating of existing fans. whether these fans are unable to remove moisture from the oven or not.
I have calculated the Actual CFM ( ACFM) considering all the process involved in the tunnel oven
We have 6 exhaust fans on the oven with 1100 CFM(SCFM)(Existing) Rating each.
Now I need to check & compare whether Fan CFM rating is ok or not.
Do we need to consider ACFM or SCFM for Exhaust fan selection. Pl. Help.
Thanks in Advance.
Som





RE: ACFM or SCFM
RE: ACFM or SCFM
RE: ACFM or SCFM
RE: ACFM or SCFM
Willard3 is correct, after three years it's very likely that the fan blades are crudded up with whatever you are drying in the oven and are not operating at their design point any more.
Also, the nature of production is "more more more", so the rate of product running through the oven is probably more than the design rate as well.
RE: ACFM or SCFM
RE: ACFM or SCFM
The Oven is baking oven and not drying oven, there are Manual dampers on the exhaust to control the amount of exhaust going out. I have calculated the actual CFM Required considering all the process involved during baking.
Now I am comparing this Actual CFM with the CFM Exhausting( considering Percentage of Manual Damper opening), there are 6 zones in the oven & 6 have different manual damper opening percentage) & I found that the CFM exhausting(considering Manual Damper opening) is less than the Calculated Actual CFM.
Hence the difference in the Air volume containing moisture is coming out the oven as water after condensation.
Now I am thinking of changing the CFM rating of the existing fans.
Please Comment/Review.
Thanks
Som
RE: ACFM or SCFM
RE: ACFM or SCFM
RE: ACFM or SCFM
RE: ACFM or SCFM
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RE: ACFM or SCFM
RE: ACFM or SCFM
In order to remove this excess moisture, I am thinking of changing the CFM Rating of Exhaust fan. I Theoretically, calculated the Actual CFM of the fan considering all the process involved in baking ( including moisture loss from product)& found that the existing fan cfm rating were less than calculated Actual Cfm.
I hope by changing the CFM of fan, this problem of water leaking from oven should solve..
Thanks
Som
RE: ACFM or SCFM
To check/verify the exhaust capacity, I would not be concerned so much initially about ACFM vs. SCFM. This might be on the order of 10-20% based on STP vs. warm air.
During the cycle, smoke-stick the tunnel entry. This should be from the more negatively pressurized room because it is the dirty side, where the equipment enters the tunnel. So if the exhaust capacity is insufficient, the dirty side is the side that is more likely to emit steam during the cycle.
On the outset, 6,600 cfm (1,100 at 6 connections) seems very high. If the tunnel entry takes in air during the entire cycle (based on the direction of smoke travel), the volume of exhaust air may be reduced. You should reduce the peak exhaust volume until the airflow between the tunnel entry and the dirty side is roughly neutral during the cycle.