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March 2004

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Subject:
From:
"Dehoyos, Ramon" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Mon, 29 Mar 2004 12:39:56 -0800
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> -----Original Message-----
> From: Dehoyos, Ramon
> Sent: Monday, March 29, 2004 3:39 PM
> To:   'TechNet E-Mail Forum.'; [log in to unmask]
> Subject:      RE: [TN] oven drying of MSDs
>
>
>
>       Joe:
>       Warm air is capable of holding more moisture than cold air.  Except, given an amount of air  ( and humidity ),  if a temp / humidity monitor is placed in that air while it is being heated, the temp monitor reading will increase  and the humidity monitor reading will go down.   .  As air is heated, it will expand.  Some of the air will be forced out and will take with it moisture.  In order for that heated air to hold more moisture, it is necessary to pump in humidity
>       Regards,
>       Ramon
>
> -----Original Message-----
> From: Glenn Pelkey [SMTP:[log in to unmask]]
> Sent: Monday, March 29, 2004 3:09 PM
> To:   [log in to unmask]
> Subject:      Re: [TN] oven drying of MSDs
>
> Hi Joe,
>
> Incoming air is 23C, 40%RH:
>
> At 90C, the relative humidity is 1.6%
> At 125C, it is 0.48%.
>
> Calculations are based on Vapor Pressure, dew point, Moisture Content, and
> temperature.
>
> http://www.usatoday.com/weather/whumcalc.htm
>
> The actual formulas used to be there, but I can't seem to find them now.
>
> -----Original Message-----
> From: Macko, Joe @ IEC [mailto:[log in to unmask]]
> Sent: Monday, March 29, 2004 11:33 AM
> To: [log in to unmask]
> Subject: [TN] oven drying of MSDs
>
>
> Technets,
>
> Commonly, Moisture Sensitive Devices (MSD) are baked out at either 125 C or
> 90 C in a convection air oven to remove moisture.  J-STD-033A requires the
> humidity to be < or equal to 5% at 90 C.  Would someone point me to an
> explanation of how to adjust the humidity content of the air at 125 C or 90
> C when say the incoming air is at a humidity level of 40% and 23 C.  If I
> remember correctly, warmer air can hold more moisture.  Is a dehumidifier
> required in the air inlet to reduce ambient humidity levels to 5%?  Look
> forward to your inputs.
>
> thanks
> joe
>
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