DCS (Dust Collecting System)

Hello to all PLCs.net

I was assigned to do a task about the I/O list of our Dust Collecting System, we have an old drawing here, but it is written in Korean and some in japanese. I have not been experienced a project this before about the DCS. So I am asking one of you if you can refer me a link or a website regarding the principle operations of the DCS. What are the interlocks or other things necessary that control this system. Even a basic ideas can do so that I can easily understand it.

Any suggestion nor question will be highly entertained.

Thanks to all of you and have a nice day.

By the way our DCS is the old one, using chain filter (not yet sure) I will try to post the picture afterwards if i have it in my pc.

Dust collection

Who is the mfg., model No. etc.?

Roger

Hey Leo,

I'll try and offer some ideas on dust collection. Not sure of your setup, but will give some details of systems I have had to work on...

Usually, there is just a start/stop station for the motor and blower. As for safeties, usually on the inspection door or doors on the system. ie, if someone is inside changing the filters, don't want it to startup. Some I have seen, on silo setups, will have a 'thumper' that operates every so often, usually about the size of a large tin can, so may be a little bit of timers on there, with air solenoids to 'clear the lines' when collecting. They just shoot a blast of air through the system to help remove residuals in the pipes.

Lastly, some will have a 'lump breaker' on the bottom to break up any large deposits that may accumulate within the container. Again, another start stop station, with a safety on any door that is removed or opened on the bottom for cleaning.

Overall, fairly simple mechanism, but feel your pain. I just had to deal with a machine that was all in Italian... and trying to remember my Spanish to at least get an idea of what they are trying to describe...

Hoot

FeedBack

Thanks to all of you about your feedbacks, I am going to put all the details afterwards. I will try to check and visit again the equipment we have here.

HootonHoller,

Thanks, actually that things sounds like the operation here. In the diagram I saw there something like that, cleaning solenoids, Big Blowers like Main Fan and Booster Fan. Their ratings are 1300kw and the voltage is 3.3KV. A lot of panel about this have there, I am going to get the details and feed here afterwards. I already made some I/O's and will attached here for your some comments.

Big thanks for this info, its gonna be a big help.

Regards,

Leo

Let's see if this helps. I've worked with quite a few D/C's in the past and from your post on the fan (1300kW), I'm assuming its a rather high capacity D/C with many rows of bags. Usually these D/C's have timer boards that control a bunch of solenoid valves that each can pulse one row of bags. What this does is eliminate either the high number of outputs needed to pulse each individual solenoid, or eliminate the high volume of compressed air needed to clean all the bags at once.

Typically thes timer boards come with an enable input that, when energized, allows the timer board to pulse these rows of bags at a certain frequency and dwell time. This input could be tied to your PLC or to a differential pressure switch that monitore air on the clean and dirty side of the bags.

What I usually do is install a differential pressure transmitter and feed the signal to the a PLC's analog input and control the timer board when the differential pressure reach a high level. This way you can determine how often you D/C is cleaning and watch out for things like broken bags.

Keep in mind that you do not want the bags to be cleaned excessively or they will wear faster. Also, the timer board should be wired such that one row of bags don't pulse its dust onto a row of bags that has just been cleaned. I usually wire the timer boards so that I pulse every fourth or fifth row of bags in succession, then start over on a different group (e.g. rows 1,5,9,..,2,6,10,.. and so on).

This is a little long winded and may not be what you're looking for, so let us know if it isn't.

Regards,
Tom

Dust Collector System

TGRAB and HootnHoller

Thanks for the info's you shared to us. I want to ask fo an apology for not replying on this for a long time. Honestly I found hard to understand what all you'd said co'z i dont have any experience working here. So after I gathered some information about this through my collegues here, i was able to understand now all what you've said. So i will illustrate here the present setup we have here in our plant. Our EAF have a big duct connected to combustion chamber then goes to settling chamber and quenching tower before going to the Bag House. You are correct, that our silo was made of full of bags inside of it. The said duct had a cold air damper installed on it and each silo is connected on it. Above the bag house also have two big duct, one is exhaust duct and the other one is reverse duct. Our main fan motor was installed on the exhaust duct and our reverse motor was installed on the reverse duct. Based on the flow diagram, it seems the operation goes like this. The main fan will sucks the dust coming from the EAF and goes up inside the bags inside the silo. Maybe at certain time, the damper for exhaust duct will closed and the damper for reverse duct will open to purge the dust inside the bag at the same time the vibration motor will on. The dust will go down and controlled by rotary valve motor to the chain conveyor. Then this dust will bring byr the chain to the screw feeder and drop it to our roots blower. After that this roots blower will blow the dust to our pelletizer drum. After several time of looking on the old drawings and check it in the site, I haven't seen any flow or pressure transmitter installed on the duct, mostly i've seen there is Temperature sesor only for indication purposes, it means i haven't seen any loop system as far as control is concern.

Dust Collector System

TGRAB and HootnHoller

Thanks for the info's you shared to us. I want to ask fo an apology for not replying on this for a long time. Honestly I found hard to understand what all you'd said co'z i dont have any experience working here. So after I gathered some information about this through my collegues here, i was able to understand now all what you've said. So i will illustrate here the present setup we have here in our plant. Our EAF have a big duct connected to combustion chamber then goes to settling chamber and quenching tower before going to the Bag House. You are correct, that our silo was made of full of bags inside of it. The said duct had a cold air damper installed on it and each silo is connected on it. Above the bag house also have two big duct, one is exhaust duct and the other one is reverse duct. Our main fan motor was installed on the exhaust duct and our reverse motor was installed on the reverse duct. Based on the flow diagram, it seems the operation goes like this. The main fan will sucks the dust coming from the EAF and goes up inside the bags inside the silo. Maybe at certain time, the damper for exhaust duct will closed and the damper for reverse duct will open to purge the dust inside the bag at the same time the vibration motor will on. The dust will go down and controlled by rotary valve motor to the chain conveyor. Then this dust will bring byr the chain to the screw feeder and drop it to our roots blower. After that this roots blower will blow the dust to our pelletizer drum. After several time of looking on the old drawings and check it in the site, I haven't seen any flow or pressure transmitter installed on the duct, mostly i've seen there is Temperature sesor only for indication purposes, it means i haven't seen any closed loop system as far as control is concern.

continue

What makes confused me here is how they will know that at this time they should close the damper for exhaust duct and open the reverse duct? what is my idea is to have a flow transmitter on the main duct so that we will know how much dust passing on it. So is it the formula given, Q = AV (Q=Disharge, A=Area of the Duct, V=velocity) is applicable also here? Our Bag House capacity is 40 tons.

About safety purposes, HootnHoller said is one of the best suggestion i got here, because in our setup we dont have any interlocks for each doors of the silo...thanks for that...

How about Pelletizer system, is it anybody here already worked on it...can you please shared to us some f your ideas...

Thanks and more power to PLCs.net

God Bless

continue

What makes confused me here is how they will know that at this time they should close the damper for exhaust duct and open the reverse duct? what is my idea is to have a flow transmitter on the main duct so that we will know how much dust passing on it. So is it the formula given, Q = AV (Q=Disharge, A=Area of the Duct, V=velocity) is applicable also here? Our Bag House capacity is 40 tons.

About safety purposes, HootnHoller said is one of the best suggestion i got here, because in our setup we dont have any interlocks for each doors of the silo...thanks for that...

How about Pelletizer system, is it anybody here already worked on it...can you please shared to us some f your ideas...

Thanks and more power to PLCs.net

God Bless

Attached herewith is the flow diagram of our DCS

Here are a couple of links:
http://www.spencerturbine.com/
http://www.gardnerdenver.com/blowers/NewBlowers/index.html