Air conditioning filter drier and silica gel

[kefah]

hi
im installing new filter drier on window types air conditioner when repairing them
as you know that they are contain silica gel to remove moisture etc
but when i opened the filter i use i discovered that they contain no silica gel
BUT CONTAIN ONLY Sieve
but the refrigerator filter dryer contain silica gel
so why

[monkey spanners]

I don't think silica gel has been used in driers for a long time. Think its not suitable for synthetic old and hfc refrigerants.

[install monkey]

isnt there a youtube vid of someone choppin up driers??:)

I don't think silica gel has been used in driers for a long time. Think its not suitable for synthetic old and hfc refrigerants.

[janegray78]

it depends on various manufacturer how they make things but dont worry until your machine works fine

[monkey spanners]

http://www.asercom.org/fileadmin/user_upload/downloads/Statements/5_ENG_Recommended_liquid_line_filter.pdf

If the drier you cut open only had a wire mesh strainer then it wasn't a drier, just a strainer. Its one reason a good vacuum is important in split ac systems.

[kefah]

I don't think silica gel has been used in driers for a long time. Think its not suitable for synthetic old and hfc refrigerants.

the system is use r22 *****

[kefah]

http://www.asercom.org/fileadmin/user_upload/downloads/Statements/5_ENG_Recommended_liquid_line_filter.pdf

If the drier you cut open only had a wire mesh strainer then it wasn't a drier, just a strainer. Its one reason a good vacuum is important in split ac systems.
so in air conditioning system filter
it must contain silica gel or not

[monkey spanners]

so in air conditioning system filter
it must contain silica gel or not

I don't know. I just use a drier that is rated for the refrigerant the system has in it. Typically Sporlan, Danfoss, Valcon.

Or if its a special part, i will order one from the equipment manufacturer.

[kefah]

thank u all

[D.D.KORANNE]

silica when hammered by liquid as it circulates thru system will always generate attrition loss resulting in silicaust which will cause system difficultues .............. the attrition loss is usually beteen 2 to 5% of its weight !

[kieran193]

I was recently at a working on a chiller on a vessel in scotland, There was a alot of sand in the system and when i opened up the core driers they were literally in pieces (as if they'd been hit with a hammer) Has anyone got any idea how this can happen or any other experiences like this one?

Kieran

[kefah]

thank u guys

[bigrac]

I found a ship air conditioning only last year with silica gel... Held inside tied ladies stockings, in the drier shell!!! 2 seperate systems, one of the 'driers' had ripped emptying silica through the liquid line!! God I hate ships!!!

[zionGREEN]

While eating silica gel isn’t an activity you should undertake, a recent article by Slate suggests that if you were to do so by accident, you wouldn’t necessarily harm yourself a great deal. Silica gel (http://personalmoneynetwork.com/moneyblog/2013/02/05/silica-gel-food-fresh/)is a form of naturally occurring silicon dioxide, better known in granular form as sand, or in crystals as quartz. It is porous, able to absorb 40 percent of its weight in water. It is also inert, non-toxic and mostly harmless. The body does not digest it, and thus is passes through the system mostly unchanged.

[xxargs]

To days used filterdrier to 99% use zeolites (molecular sieve) and alumina prepare for drying purpose, its much more efficient per volume and weight compare to silicagel in low humidity level working.

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Molecular sieve have sharp curve between complete dried and saturated state - around 0-10% Rh (~0 - 100 ppm water in R134a @ 25 degree C) and mostly saturated and capacity used (~80%) around 5% Rh (50 ppm level).

Silicagel have more flatten curve and range 0-5 % Rh only use 10-15% of total water capacity in silicagel.

Silicagel have lower usable capacity in very dry status using and need bigger filter and give back moisture to system more easy in hot situation as hot liquid line

Silicagel works best in cold side in suction line side and prefer not placed in liquid refrigerant, only in varpor side if working with refrigerant of HCF-type.

proc:

Working very quick - you can dry up 1300 - 400 ppm humidity vapour refrigerant to lower < 10 ppm water with only one slow pass ( ~ 5 gram minute flow for 12.5 mm diameter hose/pipe) trough 50 cm long hose/pipe filter packed with very hard dryed silicagel (dryed before under vacum and 230 degree C heating). Its also absorb unwanted thing as methanol, ethanol, ethymercaptane and simular polary molecules in different size. ie. cleaning up refrigerant vapour a lot This work also on HCF-refrigerant if filtred/dryed in vapour form.

cheap to buy and possible to regenerate

Silicagel together with very small amount of cobolt-cloride and yellow dyed, used still to day in indicator glasses do indicate wet (yellow color) or dry status (green color) i liquid lines


con:

Humidity not bind so hard - above 35 - 50 degree C silicagel lose capacity very quickly if want water lower than 50 ppm in refrigerant.

In case with hygroscopic refrigerant as many of HCF-refrigerant, silicagel have competition with refrigerant i liquid form about humidity and lose if not in very dry status. Silicagel in liquid line with HCF-refrigerant is not good idea. (its. why indcator glasses shifting color in range 100-200 ppm water and depend on used HCF-refrigerant (read the data sheet) , but shifting colour already 25-50 ppm range if using in HC or R12 as refrigerant)

Need bigger filter in low humidity level using


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molecular sieve (synthetic tailored zeolites) and alumina

pros:

very high absorb grade of humidity and very selective to look only for water vapor.
bind big amount up to 80% of total water capacity in 5% Rh (50 ppm water in R134a)

alumina take lower degree of water compare to zeolites and work very slow, but can take small amount of acid and very often used together with zeolites used in a burn out filterdryers.

zeolites bind water vapor very hard and can using on hot liquid side

Not so much competion of water in hygroscopic refrigerant as HCF-refrigerant, zeolites wins always the race.


con

very selective - ie, not or very low remove other unwanted thing as methanol, etanol and other polar molecules ie. only remove humidity, not other unwanted molecules, acid etc.

slow (compare to silicagel) water vapour absorption depend of compact pellet and take time to penetrate pellet whole way in.

Almost impossible to regenerate if mistake left filter drier open to air even in short amount of time, to drive out water vapour again (under vacuum pumping). you need heating up core around 300 - 350 degree C and if filter mass around and binding of pellet is not glass or ceramic type - this melt, burn, coal and collapse with loosen pellet and pellet dust after....

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for both:

If filter mass not binding/glued properly and breaks up (liquid hammering or bad choice of binding mass not compatible with used refrigerant for example using R12/R22 filter dryer i system with R134a/R407C or HC) or filter shakes as maracas from vibration over long time - both zeolites, alumina and silicagel make very hard, grinding dust and particles and is not healthy at all if this circulate in machine...

[chilliwilly]

I was recently at a working on a chiller on a vessel in scotland, There was a alot of sand in the system and when i opened up the core driers they were literally in pieces (as if they'd been hit with a hammer) Has anyone got any idea how this can happen or any other experiences like this one?

Kieran

Maybe damaged when installed and got worse over time?