fume coffin - laser cutter exhaust vent filter

by:Keyuan     2020-06-06
\"Containment and removal of laser-
Even for small laser cutting machines, the resulting air contaminants are critical. \" -
Daniel Herrick and Robert Klein
\"New health and safety issues in Makerspace\", Record of 1st academic makerspace International Seminar, 2016 ~ Laser cutting machine will produce a lot of bad smell when cutting and engraving even ordinary materials,
These gas smoke and contaminants are collectively called lasers-
Air pollutants produced-LGACs.
Even if you only cut plywood and acrylic, LGACs includes toxins and carcinogens, such as: Because the LGAC exhaust output of all laser cutting machines is effectively toxic to humans, in order to operate the laser cutting machine safely, people have to do something with bad exhaust.
There are three general solutions: the smoke coffin performs the last solution-
It is designed to help filter the exhaust gas discharged from the 50 W CO2 laser cutting machine.
The completion of the airflow test of the building indicates that the net airflow of the system is 100 CFM.
The measured value is 100 CFM, which meets the minimum exhaust airflow requirements of my specific laser cutting machine.
But if you need more airflow, you should consider modifying this manual with an upgraded fan, having more airflow under high pressure, or adding a second one on the airflow path
Although it is similar in operation to some exhaust scammers (
For example, this popular structure)
, It is not intended to produce clean and breathable air from the exhaust of the laser cutting machine in order to recycle into the working environment. (
I don\'t understand why someone would consider breathing exhaust gas from a laser cutter. )
The cost of smoke coffin materials, including consumables, is approximately $350: CanFilters brand Can 33 activated carbon filters and pre-filter (about $105)
Honeywell 24000-
Compatible HEPA cartridges (about $50).
The air filtration system has two functions: it must produce the minimum airflow required by the laser cutting machine, and it must be able to filter the air volume in that airflow with some degree of effectiveness.
Each laser cutter has a specific minimum requirement for exhaust, which is usually specified in the CFM (
Cubic feet per minute)or m^3/h (
Cubic meters per hour).
Typically, the external fan meets this exhaust airflow requirement, creating a negative pressure to drain smoke from the housing of the laser cutting machine.
In the absence of the required exhaust air flow, smoke and contaminants will hover inside the laser cutting machine or leak back to the working environment directly through the air inlet.
The filter element can only remove up to a specific maximum amount of contaminants from the air flowing through it.
Sometimes, the amount of pollutants that can be removed from the air is a function of the contact time between the air and the filter element. (
This is the case with activated carbon filters. )
Increasing the airflow through the filter may actually reduce the effectiveness of the filter because the air moves faster and is in contact with the limited area of the filter material in a shorter period of time.
For effective filtration, the minimum airflow and maximum filtration capacity must be closely matched.
But unlike the waste gas washing, it is necessary to remove 100% of the pollutants at any time.
The air passes through the filter system, and the ventilation filter has certain flexibility.
The ventilation filter is desirable to remove most of the contaminants from the airflow, but since it is Auxiliary, we can escape with less than 100% efficiency, before we need to replace the filter elements, we may get rid of a decline in effectiveness to some extent.
As long as the minimum airflow requirements are met, the filtration system is still helpful even if the filter element is not 100% effective.
There is little information in existing designs about how to build a ventilation and exhaust system.
There are few commercial exhaust filtration systems for the small CO2 laser cutting machine market.
Most of the exhaust filtration systems available commercially are exhaust washers designed to provide filtration systems that do not choose ventilation.
I took the illustrative exhaust scrubber mentioned earlier (IEAS)
As the starting point for the effective and successful filtration system of the laser cutting machine exhaust.
The IEAS system filters the laser cutting machine exhaust in the following order: I think I can convert the design into an exhaust filtration system by closing the IEAS filtration system in a closed box with a single exhaust pipe.
No need to paste the fume coffin-
Because the exhaust does not discharge directly into the work space, the charcoal dust in the outdoor exhaust is not the main problem.
I also considered the way to drive the system with a negative pressure to clean the exhaust fan
The end of the airflow path.
In the end, the design of the smoke coffin is different from that of IEAS, but it has similar main elements ---a pre-
Filter, HEPA filter, activated carbon filter, powerful fan driving system.
Efficient air filter is one of the main filter elements in the fume coffin filtration system.
HEPA filter capture
Micron-grade aerosol particles
A good source of HEPA filtration is the replacement of cartridges for many types of commercial HEPA filtration systems.
IEAS uses Honeywell to replace cartridges.
Honeywell-14 \"replacement cartridges in diameter
Because of their large cylindrical surface area, the style filter is a very good value.
But Honeywell has stopped using the HEPA filter system for these 14 cylindrical cartridges.
Company that produces Honeywell air filters.
Com, no longer make replacement filters for all 14 \"cylindrical models.
Instead, they make a filter ring with a diameter of 3 \"high 14\" and when stacked in multiples, it fits most of their discontinued filter systems.
I can also stack multiple 3 \"high rings to create my HEPA filter elements, but more parts will bring more mechanical problems and more opportunities for air leakage.
There were countless 3rd-
All parties to manufacture HEPA replacement cartridges for many discontinued Honeywell HEPA systems.
When those filter systems that have been popular before are still running, they are likely to last for years.
The 10 \"high by 14\" cartridge with a diameter of 24000 is a good value. (
It offers an interior area of 290 square feet for less than $50. )
The 24000 cartridge can be easily built into a complete HEPA filter element by sealing the bottom and top of the cylinder and adding pipe ports to the internal area. The Pre-FilterA pre-
By lining the internal area of the 24000 cartridge with air, a filter can be added to capture dust particles and prevent premature blockage of the HEPA filter
Air conditioning filter cloth (
Example 3m Filtrete A/C filter)cut to size.
Appendix to the new Pre-
I designed and built this optional pre-improvementFilter for it. Fume coffin pre-
The activated carbon filter is another major filter element in the fume coffin system.
The activated carbon filter element absorbs smoke and gas.
Because the activated carbon filter is suitable for the gas you want to place it after removing dust and aerosol particles from the exhaust air flow with a pre-filter
Filter and HEPA filter.
IEAS uses an activated carbon filter made by hand of about 20 lbs.
Bulk activated carbon packed with coconut shells.
The comments in the IEAS discussion made me look into many previousfab \"can-
The popular \"activated carbon filtration system\" in the circulating air filtration system used in cannabis plant \".
The advantages of these filters are easy to obtain, factory-
Packaging and modular.
The factory packaging should produce more efficient filtration as it reduces the possibility of the preferred air
Development channels through charcoal beds. (Also, hand-
Packing filters with bulk activated carbon is very messy.
There may be problems with safe handling and disposal of contaminated activated carbon. )Many can-
There is a sufficient amount of charcoal for the style filter models to be used for valid LGAC filtering and since they are factory-
Packed high
The efficiency of Performance Coal per pound of charcoal should be higher than that of bulk activated carbon.
Two cans here.
Style filter product line: Can 33 filter in Can filter is a good solution for activated carbon components. It has 16.
Place 5 lbs of activated carbon on a 2 \"cylindrical bed.
Activated carbon is made of asphalt coal.
Can 33 supports 200 CFM (350 m^3/h)
\"Exhaust air flow \". (
\"Exhaust air flow\" means that the filter is used for single-pass 99. 9% filtration. Single-pass 99.
9% filtration requires contaminated air to remain in contact with the charcoal bed 0. 1 sec. )
Tank 33 is a 12 \"high cylinder with a diameter of 13.
It is usually available at a discounted price from Amazon.
The 50-watt laser cutting machine comes with a Chinese-
Squirrel-cage-
By manual measurement, exhaust fans of a type running at about 115 CFMHandheld speedometer
This fan is designed to ventilate outdoors directly.
It also uses a lot of electricity.
There are many fans available for exhaust and filters.
But it is often difficult to find details about most of them.
Filters can sell a range of fans used with filters.
Their biggest fan is the Germans.
There are three speed fans.
Even under high static pressure, its consistent performance is different (1. 25 to 1. 4 inches wg).
It also has a 5-year warranty.
Note: the test of the final building showed that Max Fan 6 produced a net exhaust air flow of 100 CFM using the smoke coffin filtration system and my laser cutting machine.
If your laser cutter needs an exhaust airflow of more than 100 CFM, you should consider using a more powerful fan or multiple fans in the airflow path.
A stronger fan will probably have to be 8-inch fan.
Any fan you choose must specify that it can create the exhaust air flow required for the laser cutter at 1. 25 to 1.
4 inch pressure from the working group. (
Typically, the numbers you see in fan ads indicate that the airflow resistance is small or there is no resistance pressure.
These specifications are low
Pressure airflow cannot be used to predict the performance of the fan driving the exhaust and filtration system of the laser cutting machine. )
Put everything in BoxI and decided to put the Can 33 activated carbon filter and Honeywell 24000 HEPA filter cartridge into a sealed box, and install a maximum fan on the exhaust flange to drive the system 33 cans.
The exhaust airflow encounters the main elements of my filtration system in the following order: Honeywell 24000 will be fixed in the appropriate position, and seal the cylinder by using 12 threaded rods to clip the cartridge between the circular 1/4 plywood panel at the bottom and the smoke coffin cover at the top.
The Can 33 activated carbon filter element will be installed inside the smoke coffin box and will be ported inside to the outside of the box.
The Max fan will be connected to out-
The port of the Can 33 filter element drives the entire system by generating negative pressure inside the Can 33.
The fan sucks air from the inside of the activated carbon filter cylinder.
Therefore, a negative pressure vacuum is generated in the open interior area of the sealed smoke coffin box.
Air is drawn through pre-
Filter inside the HEPA cartridge and HEPA filter.
And 4 \"pipes-
Entering the port of the HEPA cylinder causes the laser cutting machine to exhaust.
A negative pressure drive system should prevent contaminated air from leaking into the working environment.
Because the fan is located at the cleaning end of the filtration system, the fan blades and motors have less contact with the contaminated exhaust gas, so it is unlikely that fans will be fouled over time.
To figure out how to put these parts into the box, I took the rough size of the part to Fusion 360 and designed a shell made of 1/2
Inch plywood and frame of 1x2 s.
Initially I had HEPA cylinders and Can 33 cylinders which were placed verticallyby-side.
But I re-adjusted the direction of the Can 33 filter so the fan Can connect to the end of the box.
This allows the smoke coffin to be installed in the area under my laser cutting machine.
The Fusion 360 project is completely parameterized.
The parameters of the constraint dimensions of the main parts and materials can be easily adjusted.
After receiving the part, I updated the part size with the actual size.
Similarly, the wood size is updated with the actual size.
Plywood is actually 12, for example.
0mm thick instead of 12. 5 mm (. 453\" inches)
From Home Depot\'s website
You can extract the dimensions of all parts from the following interactive viewer link.
Fusion 360 project
In addition, the complete CAD model can be downloaded from the link as a Fusion 360 archive file.
From there, you can make changes or adjust parameters to the model.
Many other formats can also be downloaded for CAD models, including SketchUp. (
I also included a DXF sketch of the plane and elevation to facilitate the re-creation of the model in another CAD program. )
Note: Building a closed box and lid is the most difficult part of the project.
Cut the panel first and use the track saw on the break down sheet to cut the panel to the final size.
I use Festool TS75 from FS1900 (75\")
Guiderail can cut width for one month-
Plywood footboard.
Pay attention to the cut of the compensation saw blade cutting.
Alternative: If you don\'t have a track saw, you can use a table saw with a plywood cutting bracket or a round saw with some sort of guide.
You need to create the following six panels :(
I try to do wood cutting with mm to avoid accumulating errors when translating between systems.
My laser cutting machine and rail saw are also made of rice. )
Cutting holes on the right side, LidI tries to cut holes on the right side
Using my laser cutter, side panel and cover, but my laser cutter can\'t cut 12mm plywood.
If you have access to laser cutting machines that can cut 12mm panels, these DXF files are provided to import laser cutting machine control programs such as laser cutting or RDWorks to cut holes.
Spare: you need to arrange 4 \"pipe holes and 4 1/4\" rod holes around the lid.
Use the following dimensions, or you can get their location and spacing from the Fusion 360 project viewer. Find the duct-
Center on the lid panel: make the following holes on the lid panel: Again, you need to lay the position of the 6 \"hole for the Can 33 flange on the right panel.
6 \"there are 6 screw holes around the hole (
12, 2, 4, 6, 8, 10 points)
And fix the flange and tank 33 in place.
Get the dimensions using the following dimensions or using Fusion 360 project viewer.
Find the center of the panel by drawing two diagonal lines from the corner of the panel.
Make the following holes on the right panel: I had to resort to drilling out the perimeter of the conduit hole and use the Fein MultiMaster tool to cut out the hole.
Fortunately, pipe holes can be a bit rough as they will be covered with flanges.
When cut into a certain size and have a pipe hole, apply a polyurethane coating and prepare the exterior of the panel with a polyurethane coating.
We will draw the inside of the box and lid in a later step. I used a water-
Based on Varathane triple thick polyurethane.
Using a track saw or a diagonal saw cutting a box frame piece that will constitute 1x2 pieces of the inside frame of the box.
You will need to cut the following parts to the following length: assemble the box and frame using a drill bit and drywall screws assemble the box from the bottom panel.
When you build, be careful to leave room for side plywood.
Check your health and size at each step.
Create and install Can 33 support si cut a 21-
The degree slope in 1x2 pieces that make up the Can 33 bracket.
I then carefully installed them in the Poole position measured from the front and right edges (167. 5mm and 50. 9mm)
Bottom panel.
I fixed the bracket from the lower side of the box with two drywall screws.
Drilling the mounting holes on the right panel of flangthe should have 6 holes cut or at least marked and the sheet metal screws will go through the flange, through the side panel and into the Can 33 filter.
If the hole is not passed through the plywood right panel by the laser cutter, then now is a good time to drill.
Loose with a large enough drill-
Install 10 screws such as a drill bit of 13/64.
Place the 6 \"flange on the right panel.
Mark the holes on the flange with marks or DingTalk.
Drill holes on the flange using a 13/64 \"drill.
Check if the holes on the flange are consistent with the holes on the right panel.
Apply foam wind and rain bands inside the flange. (
Rain band is included on the flange. )
Temporarily twist the flange in place with six 1-
Inch sheet metal screws. (It may be loose. Don\'t worry.
When you design the installation for Max Fan, fix it in place with some tape. )
While we are here, temporarily install Max Fan on FlangeWhile and put Max Fan into the 6 \"flange.
Position the maximum fan speed control in a convenient position towards the top edge of the side panel. (
I positioned it at 45-
Clockwise vertical. )
The flange is equipped with metal screw.
Mark and drill four holes on the flange to fit the Max fan.
Drill four matching pilot holes on the Max fan ring for the same screw.
Install Max Fan to the flange using four sheet metal screws.
Mark the direction of the flange relative to the right panel for future assembly.
Mark the screw position and direction of the Max Fan relative to the flange for future assembly.
Now unscrew the Max fan and flange and put the fan, flange and screw on one side.
Complete the box with polyurethane coating, apply polyurethane coating on the inside and edge of the box.
Polyurethane will help seal the case.
Assemble the frame onto the cover panel.
Make sure there is enough space for the HEPA cartridge to fit in the frame.
Make sure the lid is installed on the lower box assembly-
Don\'t be too comfortable, but don\'t be too loose to avoid the gap that causes air leakage.
Leave room for the wind and rain bands that will be attached to the lip of the cover panel.
Apply a layer of polyurethane coating on the assembled cover as needed.
Polyurethane will fill the gap between the panel and the frame piece and help seal the smoke coffin.
Cut the HEPA filter assembly to the bottom. This piece will enter the smoke coffin and serve as the bottom of the HEPA filter assembly sandwich.
I put a piece of 5mm at the bottom of my HEPA panel (1/4\")Revolution Ply.
I used the hepabottom _ mm file.
Control of laser cutting machine.
Alternative: If you don\'t have a laser cutter that can cut 14. 25\" by 14.
You can cut a piece of plywood into 14 pieces.
Square plywood made of traditional saw.
Remember to drill 1/4 holes at the bottom of the thread bar HEPA.
Apply the polyurethane coating to the bottom of HEPA for drying. Cut the Pre-
The size of the filter and insert it into the HEPA filter cartridge. Can 33 filter with pre-filter
Filter for packing cylinder.
We don\'t need this.
Filter around activated carbon.
We want our pre-
Filter before the exhaust gas enters the HEPA filter.
So we\'re going to pre-
The filter is installed inside the HEPA filter cylinder.
Cut with scissors or tinfilter to 10-1/8\" by 30-3/4\" (258mm by 780mm). Place the pre-
Filter inside the HEPA filter cartridge.
Appendix: optional pre-improvement
FilterI is an optional, improved pre-
Filter Design for placing front
In the exhaust air flow, filter directly in front of the smoke coffin.
It\'s easier to monitor and service. Fume-Coffin Pre-
We need four-
Inch length of 1/420 threaded rods.
I bought the length of 36.
So it is necessary to cut these into 12 \"with a hacksaw \".
Be careful not to damage the thread that the nut must be connected.
If necessary, burrs the end of the screw bar. Attach the End-
Cap nut on thread nut connection end
Cover nut for each 12 \"screw bar.
I used a drop of Letai (or super glue)
Inside to the end-cap nuts.
We don\'t want these nuts to loose.
Assemble the HEPA filter to place the lid upside down.
Place the HEPA filter cartridge in the frame of the lid.
It should be left, front and back.
The rubber gasket of the filter cartridge shall be firmly fitted with the inner surface of the cover.
If not, please apply a silicone caulking agent to the filter cartridge washer in contact with the lid. (
Whenever you change the HEPA filter cartridge, you will need to check and recreate this seal as needed. )
Add a washer to push each screw bar up through the top surface of the lid and into the center of the HEPA cartridge.
Stick must run inside pre-Filter material.
Place the 1/4 plywood at the bottom on the top of the sandwich.
Guide each rod through the bottom with two fingers, add a washer, a lock washer while holding the rod in place from the end, and then add a wing nut.
When assembling, all four rods should be extended from the top surface, outside the lid, to the center of the HEPA filter cylinder and through the bottom of the filter assembly.
Move and adjust the assembly as needed to make the 4 Wing nuts square with the lid.
Observe through the 4 \"pipe hole at the top to ensure pre-
The filter material is located between the rod and the inner surface of the HEPA filter.
Tighten the wing nuts but don\'t screw them too tightly.
The bottom, filter cartridge and lid should form a sealing assembly together.
If necessary, add some silicone caulking agent to the top and bottom washers of the filter cartridge to form a tight seal.
Dry dock quick installation-
Connect with a screw hole to apply a silicone oil bead on the lower side of the dry dock piece.
Quick Fixing of dry dock using wooden screws-
Connect the port to the top of the lid.
Connect the tear drop silicone waterproof strip to the licut tear drop-
Wind and rain band suitable for the shape of the cover panel lip.
Remove the tape and apply the rain tape in the appropriate place.
Safe weather zone with several 1/2 \"staples.
It should be comfortable to check the lid FitsIt, but it is easy to disassemble and must be sealed.
Drill the mounting hole into the Can 33 filter and place the Can 33 filter on the bracket in the lower box.
Press the Can 33 opening on the right panel aligned with the 6 \"hole.
Marking the screw holes on the right panel will impact the position of the end of the cylinder of Can 33.
Drill the pilot hole into the Can 33 cylinder using a 5/32 bit.
Check if the holes on the flange, side plate and Can 33 are aligned.
Apply foam wind and rain bands at the end of the tank 33 cylinder to ensure a good air seal.
Can 33 is installed in place using six stainless steel metal plate screws, and Can 33 is installed in place by screwing through the flange, right panel and Can 33 guide holes. (
You may need
Screw the screws into the tank 33 and unscrew the screws before trying to assemble all the parts. )
Reinstall the Max fan to the flange using 4 sheet metal screws and our pre-installed holes
Drill holes in step 5.
The smoke coffin is almost finished!
Connect the Toggle latch hardware the toggle latch holds the lid tightly together.
There are five toggle latches: one for each panel, except for the right panel, and two for the right panel. (
The right panel is blocked by the flange and the fan, so it has two symmetrical latches. )
Note: It\'s a bit tricky to install and adjust the toggle latch.
You may want to try one on another few pieces of wood in order to get familiar with how this mechanism works before you try to install and use them on your fume hood.
The lock and hook must be installed on the same plane.
Apart from being on the edge of the plywood cover panel, this makes it rare to have a choice to locate the lock hook.
I chose to use a rather large 8-
Install 3/4 screws for Latch hooks.
I used a variety of screws and bolts to mount the lock on the panel.
Where there is a frame behind the latch, on the right panel I used 8-3/4\" screws.
On other panels I used 6 bolts with lock washers and nuts inside.
When the toggle latch hardware is installed, the hook is first mounted to the edge of the lid with a screw. (Pre-
Drill pilot holes. )
Keep the latch screwed out so that the end of the latch is flush with the threaded pivot.
Position the lock with a \"comfortable\" snap and hook buckle and mark the position of two snap mounting holes.
Install the lock with screws or bolts as needed.
Now tighten the grip by rotating the grip Bolt so that the closed grip pulls the lid into tight fit.
But don\'t overdo it. tighten.
It will be easy to pull the latch hook out of the lid with too many levers.
You will notice that 33 cans of smoke coffins installed inside are now very heavy.
When new, it is easier to move the smoke coffin into two parts: the lower box with tank 33 and the lid with HEPA filter.
However, keep in mind that once you start using a smoke coffin, the interior is contaminated with concentrated toxic chemicals.
Every time a smoke coffin is opened, precautions are required.
When working or repairing in a smoke coffin in use, use protective gloves, eye protection, and breathing masks.
TestingI has tried the smoke coffin built here and it seems to perform well from experience.
There is little or no visible smoke or smell at the exhaust. Update [6/20/2017]
: After finishing the hand-
Handheld speedometer (
Old Kestrel 3000)
, I was able to test the air flow through the entire filtration system and the individual points in the system by disconnecting the components that started from the laser cutter-guided pipe and worked downstream of the fan. (
See table and chart)
The end result is that the system pulls out about 100 CFM from the laser cutting machine and the entire filtration system.
This is beyond my hope, but according to Voccell, my laser cutter manufacturer, the 100 CFM is enough exhaust air flow.
What happened to the airflow?
The fan can move 237 CFM without installing the filter system or laser cutting machine.
This is very close to specification.
But the pipeline and various filter elements have resistance to the air flow.
Loss in air flow (see chart)
: By using shorter pipes and fewer curves, optimizing the 4 \"pipes between the laser cutter and the smoke coffin, there is a little room for improvement.
I also shortened the post.
Fan pipe for window vents.
The final result is about 4% improvement.
So every bit helps.
Over time, the performance of the filtering system is critical.
The filter system is a new filter medium.
When the system is broken, I try to test its effectiveness and efficiency.
NoiseI tested the noise of the smoke coffin filtration system and its fans by hand
Handheld sound pressure gauge.
Unit 1 m from 59 dB I measured (A-weighted)
The fan runs at high speed.
Noise is 56 dB at low speed.
In contrast, CW-
When the compressor is started, the 5000 cooler produces 60db, and the air compressor of the air assist function of the laser cutting machine generates 62 dB.
PowerI with Kill-measure the current consumption of the fan at high speedA-Electric energy meter at 0.
Equivalent to 57 amps of 68 watts. (
At low speed, the current consumption is 0. 40 Amps. )
I\'m curious if I can indirectly measure the amount of air blocking in the system with current.
Blocking the input or output airflow causes the current to decrease by 0. 50 Amps.
Therefore, the relationship between current and airflow resistance is the opposite and therefore complex.
On the other hand, airflow blocking does not seem to exceed the fan.
A lingering problem with monitoring systems like this is that it is difficult to know when these filter materials \"run out \".
Obviously, if the filter system does not work because it does not capture the smoke or smell generated by the exhaust of the laser cutting machine, then one or more filter elements will be consumed.
But since this is a ventilation filter, you may only notice that it is on the outdoor duct.
Some filters limit airflow when they are full.
One way to measure the operating efficiency of the filtration system is that when the system is new and all filter elements are known, the airflow through the system will be smoother than the baseline measurement of the system.
An easy way to measure the baseline airflow of the system is to disconnect the pipe 1 hose from the laser cutter and measure from 4 \"post-
Fan exhaust duct in standard position. (
On my system, there is also a dry dock where the 4 \"exhaust pipe taken out of the smoke coffin is attached to the window vent. )
I measure the airflow in feet per minute (FPM)
Use Kestrel 3000 hands-
Fixed wind speed meter centered on 4 \"exhaust output pipeline.
4 \"FPM in the pipe can be converted to CFM by multiplying FPM by the area of the pipe (square feet.
On my system, the system has a baseline measurement of 150 CFM and the fan is set to speed 3. (
Note: The system baseline measurement ignores the loss of airflow in the laser cutting machine and pipe 1.
There should be no change in these. )
But a single system
The width measurement does not tell us which part of the system limits the airflow and probably how much it costs.
This is a very likely pre-
For different uses, filters, HEPA filters and activated carbon will wear out at different speeds.
Fortunately, the former
The filter can be visually checked by observing the 4 \"pipe holes.
If you use white filter material, it should be obvious when it gets dirty. Also the pre-
Filters use cheap filter materials and it may make sense to replace them regularly.
We can easily measure HEPA and pre-
Filter elements, by opening the smoke coffin cover so that the air can easily flow in and again measure the flow at the exhaust, as we did with the system baseline measurements.
The baseline airflow measurement before the activated carbon filter on my system is 209 CFM.
Therefore, it can be attributed to HEPA and pre-
The Filter is the difference between 209 and 150 = 59 CFMs.
I can compare the measurements with that value at any time in the future.
Keep in mind that values represent HEPA and pre-filter.
So it should only be with the new clean pre-filter.
Finally, the performance of the activated carbon system is only the difference between the current measurement when the lid is opened and the baseline measurement when the lid is opened.
Once we have developed some history, we should be able to predict the life cycle of each filter element.
Using a calendar or hour at this point will be the easiest-of-
Use meters to predict when each filter element is consumed.
Note: Keep in mind that the interior of the dirty filter and smoke coffin box is contaminated with concentrated hazardous chemicals.
When working or repairing in a smoke coffin in use, use protective gloves, eye protection, and breathing masks.
The filtered materials should be properly packaged and processed.
Replace Pre-
New piece size of air conditioning filter material: 10-1/8\" by 30-3/4\" (258mm by 780mm).
Open the fume coffin, remove the cover and remove the HEPA filter assembly from the cover.
Put the dirty pre-Filter material.
Proper treatment of waste filter materials. Replace pre-
Filter and reassemble the HEPA filter assembly by step 6.
Appendix: optional pre-improvement
FilterI is an optional, improved pre-
Filter Design for placing front
Line up and filter in front of the smoke coffin.
It\'s easier to monitor and service.
Fume coffin pre-
Filter replacement HEPA filter box open the smoke coffin, remove the cover and remove the HEPA filter assembly from the cover.
It makes sense to replace the pre
Filter whenever the HEPA cartridge is replaced. Remove the pre-
Filter and HEPA filter cartridge.
Proper treatment of waste filter materials.
Replacement of HEPA filter cartridge and pre-
Use the filter for the new filter and reassemble the HEPA filter assembly as per step 6.
Replace the Can 33 filter to open the smoke coffin and remove the lid.
Remove the Max Fan by removing the 4 screws that hold the Max Fan in place. Set them aside.
Screw down six screws that hold tank 33 and flange.
Put the flange screws on one side.
Filter the waste tank 33 and handle it appropriately.
Follow the instructions in step 7 to mark and install the new Can 33 filter.
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