Condensation control in blast chills
Just a question, recently we have had problems with condensation in our blast chills. Basic thermodynamics of course, very hot product, very cold metal, bam! instant condensation. What are some of the procedures you have found that can help eliminate or at least control this problem? Perhaps a period of cooling before entering the blast chills? I'm at a loss.
condensation where ? on the floor? on the product? on the ceiling?
Kind of chiller ? eg continuous iqf, batch iqf ?
kind of product / packaging ?
kind of temperatures ?
kind of loading ?
door(?) opening control system?
sooo many possibilities :smile:
Rgds / Charles.C
condensation where ? on the floor? on the product? on the ceiling?
Kind of chiller ? eg continuous iqf, batch iqf ?
kind of product / packaging ?
kind of temperatures ?
kind of loading ?
door(?) opening control system?
sooo many possibilities :smile:
Rgds / Charles.C
Sorry, about that.
Here is a for instance,
Turkey Legs, Cooked to 168F, moved to a blast chill, pre-cooled to appox 18F. Product is smoked on screens, about 12 legs to a screen, each screen is loaded on racks which hold about 8 screens, 12 racks total. No packaging at this point. continuous Ammonia chiller. Racks are loaded and unloaded into the room manually, manual doors as well.
Sorry, about that.
Here is a for instance,
Turkey Legs, Cooked to 168F, moved to a blast chill, pre-cooled to appox 18F. Product is smoked on screens, about 12 legs to a screen, each screen is loaded on racks which hold about 8 screens, 12 racks total. No packaging at this point. continuous Ammonia chiller. Racks are loaded and unloaded into the room manually, manual doors as well.
Dear kmerian,
Thks for above but where is the condensation ? what is approx. final product temp ? 4degC ? (some people call -18degC chilling), how long for one cycle ?
It sounds like a batch (ie static) freezer as against a continuous,(eg conveyor fed in/out) system. latter is typically much faster so less side-effects.
I am mainly familiar with seafood / 3 types of batch freezer - (a) basic, empty room with/without fan-driven air flow directed onto product (b) same but additional piping with ammonia cooling so as to speed up freezing, product (in trays) laid onto pipes © railroad design where product is on (racked) trolleys fed in one end in a "line" and removed from opposite.
All 3 have some problems due leakage / opening-closing door interface but condensation mainly on floor / door surround at entrance. usual solution is underfloor heating / automation /plastic curtains /education.
room Insulation problems typically manifest ice condensation at walls, ceilings.
So where is condensation ? . On the product surface? IMEX for freezing, significant condensation / long cycle / overloading > excess ice on product. If no previous problem, suggests change in usual cooling parameters, eg air velocity (if fan-driven system), input temperature, cycle time , product dimensions?
Rgds / Charles.C
Dear kmerian -
If the condensation is in the blast freezer with exposed product, how often do you clean and sanitize your freezer interior? Depending on the freezer's construction and how you move product in/out, you may have the option with FSIS to declare the interior of the freezer as a product contact surface. As long as you do a complete cleaning, Pre-Op inspection, and sanitizing, condensation falling on product would be a non-issue from a regulatory standpoint (might be other issues, given the volume of condensation). This also works if you are using a Less-Than-Daily cleaning scheme...
Thanks for the tips, I should clarify, it is the blast chill that is precooled to 18F, The product is placed in there right from the smokehouses. The condensation, basically forms on the walls and ceilings, and then drips onto the product. Basic Thermodynamics, I know, warm the air up with the steam from the hot product, metal stays cold...instant condensation.
Yes, it is static, I misunderstood. Ammonia chillers with fans to direct airflow.
The blast chills are on a weekly cleaning schedule.
Dear kmerian,
I wish I remembered more about thermodynamics.
So input = approx. 76degC (+?), move to -8degC environment. And final core temp = < 0degC? cycle time = ?
I have worked with fried fish fillets / similar input temp./ 2-3hr freezing cycle (core -18degC), (air temp.-20 to -30degC / high velocity fans) and no comparable problems although invariably some snow-frost-ice internally everywhere.
.
Difficult to hypothesise without more knowledge of process / chiller. Or maybe direct experience sub-zero (?) chilling.
Rgds / Charles.C
PS i just looked at a procedure for smokehouse meat and noticed this -
Critical Limit - Products must be cooled from 140°F (60degC) to 70°F(21degC) within 2 hours and from 70° to 41°F (5degC) within another 4 hours.
(So I presume final core temperature ca. 41degF [5degC] )?)
Above achieved by yr system ?
Yes, that is achieved by our system, we chill to below 40F as this is a refrigerated not a frozen product. Depending on the blast chill the product chills from 170F to appox 38F in about five hours. It is during the first hour of this process we have our condensation issues.
The product is moved from the smokehouse to the chiller on racks, when they are placed in the blast chill, the fans and ammonia are turned on. However, by this point the air in the room has reached probably into the 90's from the hot racks. This is when condensation forms.
Yes, that is achieved by our system, we chill to below 40F as this is a refrigerated not a frozen product. Depending on the blast chill the product chills from 170F to appox 38F in about five hours. It is during the first hour of this process we have our condensation issues.
The product is moved from the smokehouse to the chiller on racks, when they are placed in the blast chill, the fans and ammonia are turned on. However, by this point the air in the room has reached probably into the 90's from the hot racks. This is when condensation forms.
Dear kmerian,
I suspect yr room is crammed full, ie no ventilation, and/or you take a very long time to load and/or cooling capacity inadequate. Will inevitably be some condensation for sure but this sounds like a design and/or usage flaw, particularly hitting the heavy load at the initial cooling stage.
Rgds / Charles.C
Just a question, recently we have had problems with condensation in our blast chills. Basic thermodynamics of course, very hot product, very cold metal, bam! instant condensation. What are some of the procedures you have found that can help eliminate or at least control this problem? Perhaps a period of cooling before entering the blast chills? I'm at a loss.
Have you considered an industrial dehumidifier?
Regards,
Tony
Dear kmerian,
I suspect yr room is crammed full, ie no ventilation, and/or you take a very long time to load and/or cooling capacity inadequate. Will inevitably be some condensation for sure but this sounds like a design and/or usage flaw, particularly hitting the heavy load at the initial cooling stage.
Rgds / Charles.C
Do you think adding an exhaust fan to pull some of the heat out of the room would help alleviate the problem?
Have you considered an industrial dehumidifier?
Regards,
Tony
Possibly.
Do you think adding an exhaust fan to pull some of the heat out of the room would help alleviate the problem?
Dear kmerian,
I have been peeking into my refrigeration technology archive. i remember now that this is all related to Dew Point / Humidity theory, definitely not so simple. (As illustrated by Tony's suggestion). Looking at (reverse) problems relating to withdrawal / processing of pre-chilled product reveals similar headaches with respect to environment temperature.
I noticed yr OP mentioned the word "recently". Examination of recent records is often the quickest solution IMEX , ie something radical has seemingly changed, eg relating to the equipment, product or usage.
As an aside, have you been in other smokehouse chilling units? If so, are they all similar to yr situation or not, ie dripping everywhere ? I ask since i was educated on an antiquated blast freezer basically on it's last legs but which i assumed was not so atypical. Visiting a modern unit transformed my expectations, the difference being due to knowledgeable design, materials, input matched to capacity, appropriate air velocities / flow patterns / ventilation and rational operating schedules.
So, do you have a known (satisfactory) situation for comparison ? Hopefully for your own system :smile: .
Rgds / Charles.C