Air speed for drying

Fishhead
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Air speed for drying

Post by Fishhead » Sat Jan 07, 2017 01:53

In Marianski and Marianski they talk about air speed for drying. They suggest a speed of .1 to .5 meters per second.

when I search the web for slow speed fans, the technical detail is stated in cubic feet or meter per unit of time.

Any suggestion on a good slow volume of air for fan?
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redzed
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Post by redzed » Sat Jan 07, 2017 08:26

Trying to achieve the exact velocity of air in the chamber is impossible without appropriate measuring devices. You can calculate the velocity based on the speed if you were forcing the air through a duct, so probably there is a formula where you factor in the size of the chamber and the amount of resistance. Having said that, .1 to .5 meters per second is very mild air movement. Keep in mind that the reason that we want a small amount of air movement in the chamber is not that we want to dry the sausages with the air speed, but rather to homogenize the humidity inside the chamber. Excessive air velocity will result in case hardening. Often it is not necessary to install a fan inside the chamber for the purpose of air circulation if you are using a frost free fridge that turns on on a regular basis, since that task is performed by the fan inside the fridge.
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Post by Bob K » Sat Jan 07, 2017 14:53

Ditto to what Redzed said. If you are using a fridge type chamber and want to add a small fan, get a 75mm or smaller low speed or they are also available with variable speed control.
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Post by muxmun » Sat Jan 07, 2017 15:38

Along this same thought, I am using a small ceramic type heater with a low fan speed. Its pretty cold in my shop so it runs a lot it seems but just for 15 seconds or so. Anyone think that may be too much?
thanks...charlie
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Post by Fishhead » Sun Jan 08, 2017 05:23

Thanks for the replies.

I understand the need for air movement. My concern or interest centered on how little or low 0.1 m/s actually was and whether such fans truly exist.

I live in Northern California on the coast around 80 miles south of the Oregon border. At this time of year I am not concerned with temperature since ambient temperature is around 50' F. Humidity bounces around but 80% is about the going value.

I am using an old refer for a chamber and temp and humidity are steady without using any equipment. So I was more concerned about days of no air movement. Perhaps I should just open the refer doors once a day and call it good enough.
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Post by redzed » Mon Jan 09, 2017 17:31

Fishhead, an ideally constructed curing chamber has has very slow, and if not continual, regular air movement as well as regular ventilation/air exchange. But many hobbyists have had success in simply doing what you are proposing, that is to open and close the door of the chamber a few times a day. This approach, however, becomes problematic once you load it to the full with fresh product which will raise the humidity dramatically. With ambient temp of 50F, your fridge does not cut in too often so you might not have enough air movement generated by the fan when the compressor kicks in (assuming your fridge is "frost-free"). An inexpensive opton woud be to install a vent to purge the inside air using an inexpensive computer fan with a timer. Computer fans run on 12v, but you can slow it down by using a lower voltage adapter or running it through a dimmer switch.

So all I can say is, experiment, adjust and see what kind of results you get. And don't hesitate to post further questions.
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Post by LOUSANTELLO » Fri Jan 13, 2017 14:19

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Post by Fishhead » Sat Jan 14, 2017 01:23

Luosantello

I like your set up. Where did you find those fans? Did the frame come with them or is that something that you fabricated?
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Post by LOUSANTELLO » Sat Jan 14, 2017 01:36

I boughts the tracks at a hardware store. As far as the plates, I have a laser cutter, so I cut them on thr laser cutter using 1/8' styrene. I also vut spares with no hole if I ever want to remove the fans and close them up. There's a little slack in the track, but nothing a little screen hasket didnt take care of
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Post by Fishhead » Sat Jan 14, 2017 01:49

... and the fans? Did you find those at your hardware store also?

The only thing that I have so far on the web is a fan that moves 51 cubic feet per minute. My box is roughly 12 cf so I think that is too much air movement.
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Post by LOUSANTELLO » Sat Jan 14, 2017 03:24

The fans are 4" computer fans. One is mounted as a push and the other is mounted to pull. They ARE wired into a small 30.00 computer fan speed controller that allows you to alter the speed. The high voltage side of the controller is plugged into a timer that turns it on 5 minutes per hour
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Post by Fishhead » Sat Jan 14, 2017 04:24

When you said "wired into a small 30.00 computer fan speed controller that allows you to alter the speed" I expected some units behind the 30.00. I am assuming that this is some type of a rheostat. I am not especially electronically gifted, but I can usually get things wired.

As for timers, I am familiar with timers that my wife plugs in when we go out of town, but not ones that would trigger an on/off event for a few minutes every hour. Can you point me in the right direction to where I could find one of these?
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Post by LOUSANTELLO » Sat Jan 14, 2017 05:05

Here's the controller. You will need a small plug in power supply also. I will get you the voltage later. https://www.google.com/search?q=compute ... psQgTYI8AQ
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Post by LOUSANTELLO » Sat Jan 14, 2017 05:12

The timer is 20 events for on/off. Thats gets you thru 5 minutes per hour with the exception of 4 hoursunless you scatter the time a little. It's made by Woods model number 500008. Amazon under 10 bucks
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Post by fatboyz » Tue Jan 31, 2017 20:31

Just got my small chamber going and loaded full of fresh product. The RH is at 90% on its own. If I run my fan I can get the RH down as the inflow air is around 30%. My shed temp. is 13C so the chamber isn't actually kicking in to cool, and my milk fridge isn't frost free. Should I leave the RH at 90 and just run the fan a few times a day to get fresh air in, or run it lots to keep RH down?
Thoughts?
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