# Control cab filtration



## Flyingsod (Jul 11, 2013)

Have you all come across a system you really like to keep control cabinets dust free in a very dusty environment? Cabinets have drives and whatnot generating heat so cannot be hermetically sealed. 

It’s wood dust from saws. It ranges from a few microns to tangerine size chips. 

I’d love a vortex cooler in every cab creating positive pressure but the plant air here is atrocious. Sometimes the air hose is like a squirt gun. 

Been researching some but can’t seem to locate a ready made type system I can put in everywhere. 


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## micromind (Aug 11, 2007)

The compressed air idea is best, you could install one or more water filters ahead of the vortex. 

Another thing I've done is mount some sort of a blower outside in a clean area (often the roof) and duct clean air into the cabinet.


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## 460 Delta (May 9, 2018)

What kind of ambient temperature are you dealing with? A fan and filter system exists because I’ve seen them on the 24”x36” control cabinets that Command Batch used on the Eagle series. The fan was about 6” diameter and the filter was a fiberglass looking deal slid into a rack. Command used off the shelf components so it must exist. The insides were always clean it seemed if the door was kept shut.


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## Flyingsod (Jul 11, 2013)

micromind said:


> The compressed air idea is best, you could install one or more water filters ahead of the vortex.
> 
> Another thing I've done is mount some sort of a blower outside in a clean area (often the roof) and duct clean air into the cabinet.


Would def be on the roof here. The outside has conveyor belts of chips and dust that the wind whips all over. We are currently building an air cleaner out of a shipping container. Should be like an air handler room in a high rise. It’s for our giant 4160 drive room. Powers that be were unimpressed with my arguments for an air conditioner. Someday they’ll learn. 

I’ve thought about something similar. For the indoor cabinets but in some areas there’s no space and ducting would be long. 


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## Flyingsod (Jul 11, 2013)

460 Delta said:


> What kind of ambient temperature are you dealing with? A fan and filter system exists because I’ve seen them on the 24”x36” control cabinets that Command Batch used on the Eagle series. The fan was about 6” diameter and the filter was a fiberglass looking deal slid into a rack. Command used off the shelf components so it must exist. The insides were always clean it seemed if the door was kept shut.


most likely the hottest days will see 100 degrees in the mill. Some areas maybe hotter but not by much. 

Thanks I’ll look at those names you mentioned. 


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## mofos be cray (Nov 14, 2016)

460 Delta said:


> What kind of ambient temperature are you dealing with? A fan and filter system exists because I’ve seen them on the 24”x36” control cabinets that Command Batch used on the Eagle series. The fan was about 6” diameter and the filter was a fiberglass looking deal slid into a rack. Command used off the shelf components so it must exist. The insides were always clean it seemed if the door was kept shut.


I used something very similar. The guy at the supply house spec'd the parts and we cut it into the cabinet where worked for us. We cut 2 holes, 1 for in 1 for out. The fan was basically a cpu fan. We were supplied a thermostat that we mounted as well.All protected by a din rail fuse.


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## John Valdes (May 17, 2007)

At one plant I worked in we had dust and heat inside the cabinets. We went thorough air conditioners on each one and it became a full time job working on them. It always seemed like we always had at least one door open with a fan blowing into it.
Finally they hired an HVAC contractor to come in and mount AC units on the roof and run duct work to the top of each enclosure. At the time we had 15 production lines.
They were equipped so as the ambient temp outside got cold enough, they would just bring in fresh outside cold air.
This made my job so much easier. No more dusty cabinets. No more heat sink temp trips and standing next to the open door of an enclosure was very cool and comfortable.
In the 5 years I worked there this by far was the very best money they had spent. Solved three problems. Dust, heat and no more working on individual AC units mounted to the cabinets.


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## MikeFL (Apr 16, 2016)

You can get a Vortec cooler for $300.
Not sure what the Pentair's go for.


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## Flyingsod (Jul 11, 2013)

mofos be cray said:


> I used something very similar. The guy at the supply house spec'd the parts and we cut it into the cabinet where worked for us. We cut 2 holes, 1 for in 1 for out. The fan was basically a cpu fan. We were supplied a thermostat that we mounted as well.All protected by a din rail fuse.


We have similar set ups in some places and I put a few in. A decent system normally. Main problem there is air velocity. Especially in the ones where the fan blows into the cabinet and is filtered. The air moves so fast through the filter it just pulls dust onto it. Round here that requires daily cleaning minimum and prolly hourly in some spots. Ain’t nobody got time for that. 

Right now my plan is a fan or two blowing out of the cab with filtered inlets equaling at least 4 times the sq ft of the outlet. I think this will keep velocity at the filters low enough. 


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## Flyingsod (Jul 11, 2013)

John Valdes said:


> At one plant I worked in we had dust and heat inside the cabinets. We went thorough air conditioners on each one and it became a full time job working on them. It always seemed like we always had at least one door open with a fan blowing into.


We have that same situation here. I love the central air approach. I don’t see it happening here but I’ll try to work some numbers on it. Thanks. 


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## Bourbon County (Aug 19, 2020)

Hoffman makes cooling fans and intake filters as do others I'm sure, as well as enclosure air conditioners. Changing/cleaning the intake filters will add some additional maintenance work.

If you choose the vortex cooler route, might try installing a coalescing filter ahead of the vortex. The coalescing filter would allow you to dry the air at the point of use rather than drying the whole system. This would again require changing/cleaning the filter elements. The vortex might be best option in a dusty environment and since you aren't really changing the temperature to speak of it would not be a condensation potential.


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## SWDweller (Dec 9, 2020)

Any hole you put in the cabinet will allow dirt in,,,,, BAD. Fans and filters only work in clean environments. 

Hoffman if I remember correctly used to have a chart for their Nema 4x cabinets. 
Going from memory over sized the depth by 2 the height and width by 1.5. There was enough surface area that the drive would cool its self inside the can. 
The can gets bigger if there is more heat producing items,. NEVER put them on a wall, always stand them off the wall with unistrut or other products 
Mines near me are notorious for wanting products in environments that are close to impossible. Best I found with a simple search. 








What to Know When Selecting an Enclosure


In industrial automation systems, NEMA enclosures often house motor controls, drives, PLC/PC control systems, pushbuttons, and termination systems.



library.automationdirect.com


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## paulengr (Oct 8, 2017)

Don’t ventilate. Who is going to keep the filters clean? It won’t happen. NEMA 12 or 4X construction...no gaps. If you have condensation problems get one of those little Hoffman drains and use in the bottom.

Compressed air...are you insane? Lots of moisture issues and it’s never oil free. If you insist use a micro pore filter...like Goretex...air passes through but it ejects moisture and oil. Also it takes 8 HP to provide 1 HP of cooling. Vortex coolers are horribly inefficient.

You can try to figure out the amount of heat the panel will naturally dump but it’s a waste of time. Stainless panels need shade, others don’t.

So first get rid of anything you can that makes heat. Get encapsulated transformers and hang them outside the panel. Replace heater overloads with electronic or bimetallic. If you don’t mind the issues use flange mount VFDs...heat stays on the outside but replacement with new models is a pain. CVTs don’t even try ventilating.

Second add up your heat load. Drives figure it’s 95% efficient that means 5% of the total input wattage (kVA, power factor 1.0) is heat. Everything else use wattage or kVA. Outside stuff and flange mount drives ads basically zero load. If you are anal I mean an engineer Saginaw controls has a free online calculator but for sealed designs it’s easier to just deal with this directly.

Second do NOT buy panel air conditioners. Like cheap window units you will replace it every season...they are a ripoff.

If the total heat is under 1500 W (absolute largest is 3500 W) look into say a Laird thermoelectric cooler. These are solid state heat pumps. No freon. There is a big transistor in the middle that gets hot on one side cold on the other plus two muffin fans to blow air across it. 100% sealed. Great if you meet 

Going up in size if outside air is reasonable temperature then look at air to air heat exchangers. These are like the thermoelectric coolers but there’s no cooler...it’s like having a vent but 100% sealed. It just moves heat out of the panel as long as ambient is reasonable.

Finally if you are beyond this start looking at barge style (5+ ton) HVAC 480 V 3 phase. Cool the whole room. If you must vent get a large Torit self cleaning filter and run that on piped in or whole room positive pressure. It’s expensive but worth it.

I’ve done mines, foundries, wood plants, shredders. Take ventilation seriously and don’t do the $300 two filters or waste it on a window air conditioner or vortex cooler. Simple sealed solutions that are relatively trouble free are out there.


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## Wardenclyffe (Jan 11, 2019)

Inside of an air conditioned room,...


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## John Valdes (May 17, 2007)

Flyingsod said:


> We have that same situation here. I love the central air approach. I don’t see it happening here but I’ll try to work some numbers on it. Thanks.


It took the company many hours and days of debate over the AC's on the roof and the associated duct work. They finally agreed on the project.
We got a bit lucky as we were under budget that year and would have lost the funds had they not used it.



SWDweller said:


> Any hole you put in the cabinet will allow dirt in,,,,, BAD. Fans and filters only work in clean environments.
> 
> Hoffman if I remember correctly used to have a chart for their Nema 4x cabinets.
> Going from memory over sized the depth by 2 the height and width by 1.5. There was enough surface area that the drive would cool its self inside the can.
> ...


I had several enclosures with no ventilation. Some were even smaller than required for ventilation and those seemed to do well with the newer controls in them.
My biggest problems were big DC drives. They were analog back then and they were BIG. Basically a giant heater. These needed help badly and they were the cabinets that got conditioned air. I'm sure by now they have gone to AC.
Over time we added some additional smaller ducts to other cabinets. Cool air even would come through the conduit and cool other enclosures that were close.

I cannot speak for Nema 4 as every plant I worked in used Nema 12 inside. I always ordered Nema 12 for inside.
So, I do agree in some instances filtered forced air is not always needed. But to do this right you had to use bigger enclosures. Like I said though I have gotten away with smaller ones in the past.


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## paulengr (Oct 8, 2017)

NEMA 12 is the designation for dust and oil tight. It says nothing about water. NEMA 3R is weather proof which means the vents keep most of the rain out and it ventilates so condensation is less of an issue. The NEMA 4 family means you can take a 1” fire hose to it at 40 PSI at any angle. Not technically dust/oil proof but that usually doesn’t matter. NEMA 4 comes in 3 flavors. Straight 4 is painted steel or aluminum. 4X can be stainless or fiberglass but typically you see “4X SS” for stainless. It is 304 unless 316 is specified.

One trick with 4 is that it is sealed but will collect condensation. There are one way drain valves you can install to maintain the rating. In the past many plants bought NEMA 4 and drilled a 1/8” hole in the bottom. This made it effectively NEMA 3R by letting the condensate drip out the hole but with much better door seals and no vents.

6 and 6P are the true underwater boxes. Very rare 

Often “dirty” plant specs call for 4 or 12 as a minimum box. No handy boxes and NEMA 1/3R. Worst plant I worked in was kaolin clay. Clays are 0.3 to 1 micron...a seal is not a seal. They get in everything. Good thing it’s in Kaopectate ...you can eat it.


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