Ask The Experts
Welcome to the "Ask the Experts" section of the Dust Collector Experts blog. Here you can post questions that will be reviewed and answered by our panel of dust collection experts. Our staff is comprised of several professionals, from several different companies, all of whom have been working in the dust collection business for many years. Each have their own unique experiences on which to draw, and now for the first time, you have access to some of the best minds in the dust collection Industry.
It’s easy! Simply click on the link below labeled "Comments" and type your question or feel free to join in on others’ questions. The posting members of Dust Collector Experts work for some of the most respected companies in the business. If you are an expert with experience in dust collection, feel free to post.
Since all of us have day jobs, and contributing to this blog is something we do on the side, allow 2-3 days for your questions to be answered. If you use your email address, you will be notified when someone adds to your post.
If you have a question that is urgent in nature, you can call BPA at 1-800-225-6018
Jerry G. Said,
July 6, 2006 @ 2:30 pm
I have a small shop with several bench top grinders and polishers (6) and we often work with preciuos metals. What are the best systems that we can use to capture the dust coming off of the wheels that could capture and reclaim the dust? I currently use a dust collector that is very loud and does not do a very good job. maybe it is not powerful enough?
It’s important for me to make sure I am getting all of the dust.
How do I determine how much power I need at each work station?
What can I expect to spend (ballpark) for this type of machine and what maintenance is involved?
Are there machines that can cover more than one work station?
Hoping someone can offer some advice and point me in the right direction.
Dave Said,
July 7, 2006 @ 12:52 pm
Jerry,
There are a couple of ways to tackle your collection issues. First off, I’d like to get an idea of what equipment you’re currently using. See, in the wide world of dust collection, there are many factors that could potentially cause a system to fail. For example, even if you have the exact system to match your airflow requirements and collection capacity, you could have as little as one thing wrong with the ductwork layout and it would render the entire system useless.
If you’re looking to take care of virtually all of the fugitive dust, then I think your ideal fit would be either a cartridge system, or you could use a cyclone collector as a prefilter (to handle the larger pieces of dust 10µm and above), and then use a cartridge system as an afterfilter. Depending on what your exhaust requirements are, an afterfilter would not only be recommended, but in some cases mandatory. Some areas require your exhaust to be filtered, so as not to blow your waste dust into a neighboring area, or into the atmosphere. Unfortunately, the addition of an afterfilter can get rather costly, so you should definitely make sure you know if you’ll need one or not.
Depending on your airflow and exhaust requirements, your equipment cost could very well be in the mid-10k range or more… judging by the fact that you have 6 polishers and several grinders, you’re looking at quite a bit of airflow. If you can provide sizes of these tools, such as grinding wheel diameter and polishing head diameter, I can be a bit more accurate in sizing the collection equipment to give you a better ballpark budgetary figure.
Regarding the airflow needed per workstation, several factors will need to be taken into consideration. Each type and size worktool requires a certain amount of airflow, and depending on where those pieces of equipment are located in regards to the collection equipment (lineal feet of duct, number & degree of branch elbows, etc.), pressure drop will have to be accounted for in order to select the proper fan package.
In regards to your statement, "It’s important for me to make sure I am getting all of the dust:" keep in mind that using a dust collection system is not going to negate the need to sweep the shop floor, unless you’re looking at using a floor-sweep attachment for the system. The attachment is similar to a vacuum head attachment, but the amount of extra labor involved, such as running an extra duct drop, installing an extra slide gate damper, and upsizing the collector to accomodate more airflow, could almost make it not worth the hassle and extra money.
Of course, if you are not using all of your metalworking equipment at the same time, then there shouldn’t be an issue aside from the fact that your static pressure is going to be negatively affected by having to use flexible ducting, which will suffer loss compared to smooth, hard duct. All in all, you’d be in much better shape just using a shop-vac or garage broom.
Another thing to consider when looking at collection equipment is safety; processes involving some metal-working dust, particularly aluminum dust can potentially carry the risk of a spark hazard, so it is recommended that the dust collector is equipped with a spark trap or dropout box to lower the risk of a spark-induced fire or explosion. Although certain preventative measures can be taken, such as non-sparking aluminum fan wheel, the aforementioned dropout box, fire-retardant cartridge material, and fire suppression, no equipment is totally explosion-proof. You will want to consult your local fire marshal and reference local/national codes for any requirements.
I hope this satisfactorily answers your questions. Please feel free to post any other comments or questions you may have, and thanks for dropping in.
joe Said,
July 15, 2006 @ 10:22 am
hi, i am about to start working on a glass tile mosaic and i want to create some kind of dust collection/vacuum system, where four or five people, hand cutting glass tile won’t breath in the glass dust. i envision using multiple adaptors mounted to the edges of the table where tiles could be cut over and sucked down and where fragnments of broken glass could be swpt into. ideally i could have at least one flexible hose that could be used as a movable vaccuum hose. cost is an issue and so is the noise level, since it will be running all day. i first considered buying two fein vacuums but was concerned that the motors would burn out. thanks! i look forward to your response
Dave Said,
July 20, 2006 @ 11:22 am
Joe,
You have a valid concern with using shopvac type systems for your application. While those are adequate for small hobbyist applications, say, cleaning the garage floor after building a birdhouse, your chances of being able to effectively use one of those for in-process source capture of glass dust are rather slim.
Since you have multiple capture points, you will most likely be best suited by a stationary cartridge collector, with multiple drops to accommodate each pickup point. You may also be able to use a floor sweep attachment, which is designed to accept dust that is swept into it, minimalizing the use of your favorite dustpan. Depending on the quantity and size of your workstations, you may be able to use a downdraft table, which is designed to collect the dust in the exact method you mentioned above. Of course, you will still need to handle the larger glass shards manually.
I hope this provides you with the answers you need…please feel free to contact me with any other questions.
Tan Lim Poh Said,
August 1, 2006 @ 10:14 am
i m doing research regarding wet type air cleaning devices used in factory. i lack of information for the research. Did you hear that wet-type precipitator before? It’s a type of wet type dust collector which used in industry. But it seem very unfamiliar in dust collector field and lack of basic data in internet nowaday. Could you provide any informations about this kind of wet-type dust collector to me for research paper.
admin Said,
August 5, 2006 @ 3:02 am
Tan,
Yes, we’ve heard of wet scrubbers before; actually, we recently started looking into using them due to some processes that we’ve been evaluating lately. I’m currently working on a project involving a syrup liquid by-product from a bottling application. I am looking at a wet scrubber mainly because that’s basically the only type of collector that will effectively address the issue.
Lou Aiello Said,
December 26, 2006 @ 1:25 pm
If I have 2 equally rated units – They’re about 650 CFM each, though I’m not certain the size matters for the purposes of the question. Assuming all things equal such as all tools are the same distance from the units and on the same size hose and I only have one gate open at a time, etc. , am I better served using a “Y” and operate them together into a main line or should I split my shop into two equal circuits and run them separately?
Dave Said,
December 29, 2006 @ 11:50 am
Lou,
For all intents and purposes, if you have 2 collectors and 2 capture points that need addressing, dedicating a capture point to each collector would ultimately yield better results – this will lower the risk of air balancing issues that may occur with running multiple duct lines and dampers, as it’s a pretty cut-and-dry installation from point A to B.
James M Said,
December 31, 2006 @ 1:03 am
Hi
I am wondering what techniques are used to minimise the live – blocked hopper loads.
Our DCE 3/3/10 is mounted on a shiploader boom and we need to look at reducing the max. 14T of live loads as far as we can.
The 3/3/10 is turned 90 deg. and is fitted with 2 pyramidal hoppers under the bags ie conventioanl arrangement. The dirty gas flow is from the side.
The hoppers and bag chamber can completely fill with dust if there is an issue with the rotary valves.
I was thinking about….
making the dirty gas entry bottom entry > in the beleif that when the hopper fills up with dust – it will cut off the gas flow and hence. limit the filling degree of the chamber.
install inserts into the hopper to minimise the total volume and hence loads.
Thanks
James
Waly Said,
June 7, 2007 @ 2:42 am
represent an Egyptian company that manufactures Dust Collectors. Currently, we are trying to out source electric controls for the filters cleaning mechanism.
If you are unfamiliar with that process, here is a brief description:
A number of Solenoid valves open every [30 seconds] for a duration of [10 to 30 msec]. The solenoid valves do not open at the same time but they precede each other by equal times within the overall cycle time.
This application is very popular of course and I am sure that you have dealt with similar requests. Please advise me of what solutions you have to offer keeping in my mind that I do have a poor understanding of electronic equipment!
static bag Said,
June 29, 2007 @ 3:27 pm
static bag…
Hi. Thanks for the good read….
nfettes Said,
July 27, 2007 @ 12:36 pm
I have a few questions about cyclones.
1) Can a cyclone have a maximum flow rate? And if so, what happens if the fan is turned up beyond what the cyclone is designed for.
2) Along the same lines, is there a maximum pressure drop a cyclone can perform under? And if so, what if this value is exceeded?
3) Can a fan be hooked up to the inlet or the outlet of the cyclone?
Thanks,
Nathan
JordanC Said,
January 7, 2008 @ 6:59 pm
Hello,
I am trying to figure out what type of dust collection unit I should implement in our shop and of what size it should be. I am a college student who has been giving an opportunity to work on a project for a wood specialty company. This project will be implemented in reality as long as a cost effective system can be put in place or combined with the existing setup.
Currently we have three main lines in which separate branches enter into from different machines, with three blowers inside the shop for each main line. Two 50 horsepower blowers and one 15 horsepower blower. The main lines converge, after exiting the shop, into a rectangular exhaust port which enters into the side of our hopper. We are not recirculating the air BUT want to do so now to save on heating costs in the winter and provide employee comfort. I have two questions that I would appreciate if you could anwser if any of the questions in this blog at all:
1) Can the existing three main line system be used in combination with a new heat recovery unit ( cyclone unit/baghouse unit), or does there need to be a round entrance into the unit instead of a rectangular one? Or must there be one main line with branches entering into it that goes into the cyclone/baghouse unit instead of three separate main lines?
2) Which unit would work best (or be mandatory) for this situation of recirculating air into the shop, a cyclone, baghouse, etc… ?
The shop conists of 9 industrial size lathes, with horizontal shafts about 4 feet in length with varying turning lengths set on each of them. There are also three other machines I am currently looking at and taking measurements on. The lathe hoods are all similar in design: rectangular faced plenums about one 1′ X 3′ into 10″ ducting and also 11.5″ ducting with a semicircle hood piece attached to the face of the plenum for protection from debris flying out (I’m guessing). The semicirle hood piece kind of wraps half of the lathe shaft to enclose the process better for extra safety I’m assuming. I’m guesstimating a distance of about 3′ from the “source” to the ducting entrance which is connected into the plenum (have rough measurements right now).
The duct velocities of the blower outlets for the main lines, after the conversions of the pressure measurements were done: 7,400 ft/min ,
8,600 ft/min and 8,913 ft/min. I’m thinking this is about 36, 760 c.f.m total flowrate, but not sure if I can just take the velocities and main duct diamaters to calculate that.
I am not sure if the sizing of the ducting should be changed or not, but I am investigating this matter as well as gettting more information on the system.
Would the 3′ distance from the “source” to the ducting start be reason for such large diamater of branches even with a smaller turning length on the lathes? And is this distance considered the Capture Points (take-offs) as described in the “Dust Collection Pre-Qualification Form” provided through this site? I hope to fill out the form and get some feedback as the form will allow more details on the machines themselves.
With measurements of all my hoods, and sizing of all my ducts, should I be able to size a unit, or do I need the type of wood being processed? If so, how would I go about calculating losses and whatnot if I have an unknown mixture of wood dust/shavings and air, this has been a problem I’m not sure how to address either because there is two different density values at an unknown mixture. I was thinking that a generic value is giving assuming dry or wet etc… and the calculations were done maybe this way?
If any of these questions are legitimate, I would greatly appreciate it if someone could anwser any or all of them for me.
Thank you very much, Jordan.
In closing, I have many, many questions as this is my first experience with a dust collection system. I understand the complexity involved in designing and sizing a system, but am very unsure of a starting point for this project. There are so many variables involved, like the density problem, and such that I am getting somewhat frustrated but increasingly interested
If you could please anwser even one of my questions I would greatly appreciate it, and if at all possible I could use a break down on a step to step basis for designing or modifying a system from scratch to accommodate a new Cyclone or Baghouse Unit
( if these are possible options). Thans again, Jordan.
Anna Said,
February 18, 2008 @ 3:01 pm
I have a question that I should probably know the answer to…
If I’m using HVAC duct work for my dust collection system, which way should the joints fit together? I’m guessing that the smaller end should aim toward the dust collector. I ask because the dust collector itself has a port which is too small for the small end to fit inside, but the large end fits over it. Maybe I should just crimp the smaller end more so that it will fit. What do you think?
bob Said,
March 4, 2008 @ 8:42 am
I work for an Industrial laundry. One of our specialties is cleaning filter bags for reuse. 90% of our customers are from the wood industry (windows/doors, flooring mfg, cabinet makers etc.) Our customers are very satisfied with the results and will usually turn filters in 3 -4 times for cleaning before replacing with new. Some have even said the filters are more efficient after the first cleaning than when they were new. Besides the word of mouth from my customers, would you know of any research that has been done that would substantiate their views on how filters perform after washing compared to a new filter?
Thank you!
Bob
bob Said,
March 11, 2008 @ 1:18 pm
Hi,
I asked this question last week and am not sure it went through. I work for an Industrial Laundry and one of our specialties is cleaning filter bags for reuse. I know most filter bag manufactures erccomend only replacing filters with new filters. Of course if that is what I was selling that is what i would reccomend also. But I have many satisfied customers across the US that send in their filters on a regular basis for cleaning. They will replace a set after 2 – 5 washings. My questions is, do you know of any research that shows how washed filters perform?
Thank you!
Bob
bob Said,
March 24, 2008 @ 9:28 am
I am guessing that since there has not been a comment made since Dec of 06 that there is no one around to answer any questions any more. I have sent in two questions this month and no response.
rpcrawford Said,
June 5, 2008 @ 12:56 pm
I run a small coal testing lab and I need to control the dust around a grinder and a pulverizer. This equipment will not be operated at the same time but is mount side by side. When they are in service, fine dust leaks out of the joints and gaps in the housings. Each occupies an area about 4′x4′ and will run about 3 hours each day. The leakage is very fine dust, my best guess is that most is less than 2-3 microns.
We would like to return the air back into the building to reduce the A/C load. What type of system might work best in this application?
j.edwin Said,
August 12, 2008 @ 10:36 am
We have a dust collector with the tubular bags. We have an EPA requirement to maintain a pressure drop of between 2-6. Lately we are having a higher than normal reading, 8-10, even after blowing down the dust. Can’t find any leaks. What can I do?
Thanks
yossi Said,
September 10, 2008 @ 5:48 am
Dear All
What is the advantage and the disadvantage of air pulse jet cleaning system to reverse blower dust system beside of the air consumptions?
What is the advantage and the disadvantage of tubular vertical bags to horizontal bags (envelope)?
Thanks
yossi
admin Said,
November 24, 2008 @ 3:12 pm
In response to rpcrawford question…
Your application would be well suited by either a cartridge or a baghouse system, as these systems are designed for high efficiency filtration of fine dust particulate, usually rated at 95% or higher for 0.5µm. Most units will have an option for a final-stage “safety afterfilter,” to ensure that the discharge air from the collector is virtually free of contamination. Not all applications require fine dust filtration to that high degree, but many enjoy the peace of mind that is given when they don’t have to worry about the efficiency of their pollution control system.
For your circumstance, the method of capturing the dust will play a critical role in how well the dust collector will serve its purpose…while there are many potential options available as far as equipment goes, inaccuracies in duct and capture point design can render useless an otherwise capable dust collector. For more information on dust control, visit OSHA’s website: http://www.osha.gov/SLTC/silicacrystalline/dust/chapter_3.html, or pick up a copy of the ACGIH Industrial Ventilation Guide.
As with any dust collection system, special requirements or considerations may be necessary for the type of dust you are handling, so check with your local Fire Marshal and insurance carrier, and reference local and national NFPA codes and guidelines for any considerations or requirements.
electric supplier uk Said,
December 22, 2008 @ 5:56 pm
electric supplier uk…
2 Thumbs up. good post…
Eric Said,
December 26, 2008 @ 8:41 am
air testing equipment…
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Jack Said,
December 30, 2008 @ 4:35 pm
air cleaning equipment…
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elchinas Said,
January 2, 2009 @ 10:28 pm
hello…
thanks…