Yes, if you have confined environment around your laser this will do the job.
Good Luck!
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Joyce Koo
Sent: Wednesday, March 08, 2017 12:54 PM
To: [log in to unmask]
Subject: Re: [TN] humidity control
yap...I guess the only thing to do is this...
http://www.instruquest.com/HumiSys.html?gclid=Cj0KEQiA9P7FBRCtoO33_LGUtPQBEiQAU_tBgKiF73qFonCaBXamdWm9y2g9DmuaawvVBziAD2-Gb5kaAv0k8P8HAQ
no easy solution..
jk
> Part of your problem will be intrusion through the spaces in walls and
> ceilings.
> If you dehumidify the space the moisture will try to equilibrate with
> the surrounding areas.
> You might have to seal up the whole thing with plastic.
> There are really large dehumidifiers that basically bake the air but
> then you won't be able to hold your temperature spec.
>
>
>
> Chuck Brummer
> Medical Flex, EMSD
> 8357 Canoga Ave, Canoga Park, CA 91304-2605
> Office: +1 818 734-4930 | Mobile: +1 805 890-8452 [log in to unmask]
>
>
>
>
> -----Original Message-----
> From: [log in to unmask] [mailto:[log in to unmask]]
> Sent: Wednesday, March 08, 2017 10:14 AM
> To: TechNet E-Mail Forum <[log in to unmask]>; Chuck Brummer
> <[log in to unmask]>
> Subject: [EXTERNAL] Re: [TN] humidity control
>
> Many thanks Steve and Chuck. the room is not cleanroom construction...
> that is the problem... I guess I got stuck between the rock and hard
> place... thx. (might be able to recycle air - with minimum inlet and
> control temp only, and deal with RH as separate issue - moisture coming
> from the walls for example).
>> Oh Boy,
>>
>> How high are the ceilings? What are the walls finished with? Luckily
>> the room is not that large.
>>
>> Your right, humidification will not be that difficult.
>> Dehumidification, much harder and your local HVAC guy has no idea.
>> You need an air handler to get enough air into your room to make it
>> positive pressure. You need a large enough compressor to cool air
>> moving faster than typical over the coils.
>> You need a reheat unit to warm the air moving through the coils when
>> you have not met your RH requirement. Typically you have two
>> compressor systems so that on runs 24/7 and the other comes on and off
>> on demand.
>> Your RH requirement is much lower than ours is so your compressors
>> will run often. I have a +/- 4% spec and we can hold that at a target
>> of 48%.
>> Find a cleanroom designer to spec your system for the HVAC contractor.
>>
>>
>>
>> Chuck Brummer
>> Medical Flex, EMSD
>> 8357 Canoga Ave, Canoga Park, CA 91304-2605
>> Office: +1 818 734-4930 | Mobile: +1 805 890-8452 [log in to unmask]
>>
>>
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
>> Sent: Wednesday, March 08, 2017 6:14 AM
>> To: [log in to unmask]
>> Subject: [EXTERNAL] Re: [TN] humidity control
>>
>> Hi Joyce-
>>
>> Doesn't exist.
>>
>> Humidification is easier than de-humidification but is still problematic
>> because boiling water is a violent process at the molecular level and
>> can
>> be corrosive.
>>
>> Properly conditioned air is a very precious and expensive commodity. The
>> first rule is that you have to treat it that way: You need to know how
>> much air is leaking out so you know how much capacity you need for
>> humidification/de-humidification. If you use robots in a sealed plastic
>> bag you will still need to provide a little make-up air to keep positive
>> pressure in the clean room. But add people and they put out humidity
>> too!
>> And they consume oxygen so a certain amount of "fresh" input air is
>> required. A U.S. standard for HVAC is 20CFM/operator, which seems quite
>> high unless these operators are doing very hard physical labor.
>>
>> On many cleanrooms, the HVAC contractor had no business designing the
>> system because they have no experience with the practicalities of the
>> velocities and pressures involved. They try to get by with a standard
>> rooftop commercial HVAC unit of higher capacity to get the number of air
>> changes per hour up to the requirements of the cleanliness level. When
>> you
>> really start treating air as a precious commodity you will find these
>> commercial units are basically un-sealed (partially because the
>> differential pressures involved in the cleanroom are larger than what
>> they
>> designed their little weather strip seals for.
>>
>> I had pretty good luck using the area above the cleanroom ceiling as a
>> simple mixing plenum: A standard rooftop HVAC unit, sized appropriately
>> for the load (not oversized like most commercial buildings), kept the
>> plenum at the required temperature and supplied the required make-up
>> air.
>> A separate loop went through the de-humidifiers (ducted) and the HEPAs
>> were just self-powered. The humidifier was just one of the wall mount
>> units like many SMT areas have. If you have designed properly than you
>> shouldn't need to put a heater in the system to get the air conditioner
>> in
>> the HVAC unit to act like a dehumidifier--the solution most commercial
>> HVAC designers will try to sell you on.
>>
>> But even with the degree of control I had, 30-34% is too tight a range
>> to
>> be practically feasible. I was happy with being able to maintain a 10%
>> range. And that's near the low side. If needed in the spring when
>> temperatures are moderate, then it may be unavoidable to use a
>> re-heater.
>> You don't provide a temperature range, but if you can tolerate swings in
>> that then I can see 30-34% being achievable by increasing/decreasing
>> temperature in addition to the other controls.
>>
>> By the way, this is a control system, so it is not difficult to get it
>> to
>> go unstable. One cleanroom I oversaw would have swings of 50%RH within
>> 10
>> minutes!
>>
>> Wayne
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Joyce Koo
>> Sent: Wednesday, March 08, 2017 5:43 AM
>> To: [log in to unmask]
>> Subject: [TN] humidity control
>>
>> Guys and Gals,
>> Does anyone know a unit (reasonably priced and compact) to control
>> temperature at 21 C+/- 2 C and RH (I know it is hard one) at 30-34%
>> capable of constant maintaining within the range? The canadian
>> winter/spring is crazy, especially for the RH.. we can swing from
>> extreme
>> dry to rain within few hours. I know majority of control are for (1)
>> office - not going to work (2) electronic cleanroom - >40% RH... but I
>> do
>> need 30-34% RH to get laser working. Many thanks.
>> regards,
>> jk (already got 4 dehumidifier in the room of size
>> of 29'x12') 3M security scanners have not detected
>> any malicious content in this message.
>>
>> To report this email as SPAM, please forward it to [log in to unmask]
>>
>
> 3M security scanners have not detected any malicious content in this
> message.
>
> To report this email as SPAM, please forward it to [log in to unmask]
>
|
