Smelting Blower Specs

[J.Arthur Loose]

I'd like to find a reliable, portable, QUIET blower for smelting & hearth melts.

Anyone have a sense of specs in terms of CFM & air pressure?

I see some available with ranges like 116CFM / 65mmAq or 180 CFM / 79mmAq.

Will this do the trick?

[timgunn]

The nicest one I've seen in use was a side-channel blower at one of Owen Bush's hammerins.

I think Owen's was a Nash/Elmo/Reitschle and had about a 1/3 HP motor. I'd guess it was probably a GBH1100.

http://www.gd-elmorietschle.de/uploadedfiles/elmo-rietschle/downloads/content_g/datasheets/g-bh1_g-bh9/standard/2bh1100_ie1_en.pdf

There are several other manufacturers, since it's pretty old technology.

Side-channels tend to be used where the pressure requirement is higher than can easily be supplied by a conventional centrifugal fan. Centrifugal fans need to be large in diameter or run very fast to give much pressure rise. Side-channel blowers are able to provide usefully high pressures from a very small diameter, whilst still being able to use a conventional induction motor. The impeller is usually mounted directly onto the motor shaft and there are no other moving parts, which means that the motor is what determines the lifespan of the machine. With a "proper" industrial motor, ten years or more of continuous operation is quite common.

Also called regenerative blowers, the side-channel units are very quiet.

The big advantage of a side-channel is the performance curve, which actually increases the pressure rise as the blower is throttled. This means that the power consumption increases as they are throttled and it is usually better to control the airflow by bleeding off surplus air, rather than simply throttling them.

For a conventional centrifugal blower, the 116 CFM/65mmAq description usually means that the blower will flow 116 CFM at zero pressure differential and will generate 65mm Water Column (about 2 1/2") of differential pressure at zero flow.

We tend to want some pressure at some flow, so the 116 CFM/65mmAq description is not very helpful.

I did a calculation to try to work out whether the CFM value of a forge blower would be particularly helpful in making a selection (I don't think it would).

I calculated that 1 CFM of air would provide enough Oxygen to burn 0.42 lb/hr of Carbon to Carbon Dioxide or 0.84 lb/hr of Carbon to Carbon Monoxide. I can email my calculations if anyone wants to check them. 

In a smelt, I think you want Carbon Monoxide, which will then reduce the ore, Oxidizing to Carbon Dioxide as it does so.

If my calculation is correct and you know roughly what your intended charcoal(?) burn rate during your smelt will be in lb/hr, divide it by 0.84 to get a ballpark figure for your CFM requirement. For a smelt burning 200 lb of charcoal over 4 hours, you'd burn 50 lb/hr and need (50 lb/hr)/(.84 CFM/lb/hr) = 60 CFM in round figures.

 

 

 

 

 

[J.Arthur Loose]

Thanks, Tim. The side channels look a bit less common in the States, although I found distributors of new ones. Seems weird.

 

I ordered one of these off Ebay, the 116630 variety. $150. Looks a hair more blower than the one recommended by some notable smelters...

 

http://catalog.ametekdfs.com/pdf/5.7 (145mm) BLDC Thru Flow Windijammer 250 Watt 120 Volt Standard Flow System.pdf

 

It says 66 CFM, and 50" H20 max sealed pressure. So I'm hoping that means what I think it means. All the charty looking thingies look promising.  

[timgunn]

It should eat the job. The curves look excellent.

If I'm reading things correctly, the 116630 has variable-speed capability, taking a 0-10V speed signal, and should be very easy to tune to match the actual duty required. 

I've never even seen any of the windjammer series in the flesh, though I've used Ametek Rotron Side-channel blowers in the past and found them very good. I used them on Landfill gas systems and the units I used were much bigger than we would typically use for forges/smelting. They were very well-engineered and I'd have no qualms about using Ametek products based on that experience.

 

[J.Arthur Loose]

Thanks for the confirmation, Tim. After looking and comparing, I thought it would be a decent blower. I sure hope it's well-engineered... new ones go for US $1000.

[J.Arthur Loose]

Hey Tim- or anyone else who might know...

The blower has arrived, but I have questions about the control. It wants a "0-10 VDC isolated speed control." I called the company and they just sent me the same thing I'd found online, which just says this:

"Speed Control: E (Electrical) Pulse Width Modification or Analog input voltage (user supplied) 0-10 Volts DC 10mA maximum. 3-15 Volts DC. Access to sensitivity adjustment for 0 - 10 VDC speed control. (ref. pin connection.)"

 

All of which sounds like a little bit of mumbo jumbo. I will also note that my pin connection is one pin off from the illustration.

 

You can see the full doc here: http://catalog.ametekdfs.com/pdf/5.7 (145mm) BLDC Thru Flow Windijammer 250 Watt 120 Volt Standard Flow System.pdf

 

It sounds like I need a separate power supply going to a device which will put out 0-10 VDC rather than a simple 0-10 VDC dial, for example. Some fans do supply their own power, however, and the sales rep for Ametek didn't seem to understand the question, which in my experience means it's either a smart question, or a really dumb question. LOL

 

Any words of wisdom?

[Jerrod Miller]

If I am reading that all correctly (and I may not be), I think you do indeed need a 0-10 VDC power supply, and it will draw no more than 10mA.  That being the case, I think all you need to do is add something like this guy into your system.  I am not entirely sure, but I think you can just splice it into the same power cord going to the blower and you should be able to steal the tiny bit of power you need off of your main power to the blower.  

So with that unit I linked, I think it would look like this:

Wall (either it's own plug, or spliced in at the blower main wiring) -> dimmer (4 & 5 in) -> Blower (1 & 2 are your high and low pins)

and

Wall -> Blower (Line in and Neutral)

The biggest thing I am not sure about in this is the 10mA.  I don't know if my solution here would allow more than 10mA through and fry the control on the blower, or if the 10mA is just the stated max draw and if it has the ability to get more it will still be OK.  Adding a 10mA fuse in line before the hi pin should make it safe.  

Again, I may be wrong.  

[timgunn]

Jerrod's suggestion looks good.

The way I read it, the input resistance is sufficient to draw no more than 10 mA at 10V (so presumably at least 1000 Ohms).

The unit Jerrod linked to seems to give a 1-10V output at up to 30 mA. The important thing is that it is a Voltage output.

Something which gave a 0-20 mA current output instead (another common control signal) probably would not work.

I can't see anything similar available over here, so left to my own devices, I think I'd probably do it using a 10V power supply and a potentiometer. Connect the supply across the ends of the potentiometer and connect the +10V end to the "high" pin. Connect the wiper to the "low" pin. Adjusting the potentiometer will then adjust the speed. When the wiper is near the +10V end, speed will be low. When it is near the 0V end of the potentiometer, speed will be high.

[J.Arthur Loose]

Jerrod, after poking around, and wondering if something like that would work, I think you're right. Simple and cheap.

 

LOL a 9v battery works just fine too.

 

Thanks, guys, for the brainstorming before I potentially blew a $1000 blower I got for $150.

[J.Arthur Loose]

Just as a follow-up- I finally tracked down the exact item to make it all happen for $25 on Amazon. Works great- cruises from nearly silent gentle push for hearths up to relatively quiet blast that should run a full smelt just fine. Bonus points for blue lights on the transformer & a digital readout.

 

https://www.amazon.com/DROK-Adjustable-Changeable-Transmitter-Simulation/dp/B071NLGP6L/ref=pd_lpo_vtph_107_bs_t_1?_encoding=UTF8&psc=1&refRID=RMDQYWWHM0GG9M29FS4J

 

 

[Eric Dennis]

I've been wondering about blowers as well lately as I'm hoping to find a reliable one soon.

Forgive me as I don't know a lot about electronic parts. Is there a blower that others have used and been happy with that doesn't require modifying or adding further vdc's and such? More of a "plug-n-play", so to speak? I'm looking for an example to compare specs with in my search. 

Any help would be appreciated as my last smelt (and first) I used a shop-vac that was far too powerful and had to be kept outside of the copper tuyere. The bloom ended up coming out in pieces and was not ideal.

thanks,

Eric

 

[Alan Longmire]

You can still use the shop-vac, but get a router speed control from Harbor Freight.  They're usually around $30.  You can use it to turn the vac down so far it whispers, or up to full blast.  

If you can find a genuine antique Variac they have a much higher cool factor, though.  If it still works, that is.  Jesus Hernandez, Dennis McAdams and I fried Jesus's Variac in 2014 at the start of a smelt.  Luckily there was an HF store nearby.  Jesus is still using that router speed control last I heard.

[Eric Dennis]

Hmmm... interesting. And the router speed control won't burn out the motor? and how does this vary from a vdc?

Thanks for the idea!

Edited September 21, 2017 by Eric Dennis

[Don Abbott]

1 hour ago, Alan Longmire said:

Jesus Hernandez, Dennis McAdams and I fried Jesus's Variac in 2014 at the start of a smelt.  Luckily there was an HF store nearby.  Jesus is still using that router speed control last I heard.

That was at Bowie's. right? I remember that flurry of quick thinking!

 

20 minutes ago, Eric Dennis said:

Hmmm... interesting. And the router speed control won't burn out the motor? and how does this vary from a vdc?

For several years my first forge blower was a stripped down upright vacuum cleaner plumbed to blow instead of suck.

I used a cheap click & turn light switch dimmer to vary the speed. They just add resistance and lower the voltage.

A lot of folks said it would ruin a cheap AC motor, but it was still working when I quit using it.

[Alan Longmire]

That was indeed at Bowie's, and I remember you looking at the guts of the variac after I took it apart with a swiss army knife on somebodies tailgate.

And the speed control is just a variable resistor.  Works great on small electric motors, but not on big ones.  A vfd is a transformer that converts single phase to three phase, dunno what a vdc is.

[Jan Ysselstein]

Alan,    guts of the variac   a variac is a variable transformer  ( varies voltage ),  a rheostat is a variable resistor.

[Alan Longmire]

Thanks, Jan!  Good to know.

[Daniel Cauble]

All we use is a 110 CFM shopvac from Home Depot and a rheostat. Cheap. The vacs have seen more smelts in a year than most people do in a lifetime.

[Eric Dennis]

Well, considering most people likely don't do a smelt ever- that's not necessarily a good track record.

just kidding, thanks for the info. It's nice to hear what others are using so I have some sort of baseline to go off of.

[Jan Ysselstein]

Sears $ 29.00 vac+variable trans former.... for forge , smelting, and crucible furnace. I probably buy one every 2 years. The flexible plastic hose is the problem..it has a loud whistle sound ( deafening). Replace the hose with a larger diameter hose and you are fine. I often place a paper cup over the air intake so all the air I get is the cooling air which is being pulled through he motor...this for low temperature applications. Right now mine is reluctant to run smoothly at 20 V...I can fix it ..but for $29.00 it may not be worth the time.

[Eric Dennis]

Hi,

I purchased a setup similar to J.  Loose's. The catch is I  know very little about wiring up electronics. Can anyone give me insight into how to hook this blower up? I understand that the  signal generator needs it's own power supply, though it requires "dc12-24v". Does this need to be a  DC adapter, for instance  like this  ? Or  are the amps too high on that power supply? Likewise, I'm not sure which wires should hook up where, and my wire colors are different then those in the photo above.  Thanks in  advance for any help- hoping to learn.

Edited June 12, 2018 by Eric Dennis

[Eric Dennis]

Well, I'm currently answering all my own questions. I should have thought about this harder I guess. I found an old laptop charger to give the generator power- worked like a charm- just stripped the wires. I called the company and found that my wires are: blue=command low, red-command high, white= neutral, and black=AC in HOT.  

[Alan Longmire]

Good to know!

[Eric Dennis]

I tried hooking up the blower and I'm having trouble. I'm wondering if the blower's electronics are shot. The only way I can get the blower to run is in the first configuration. However, it only runs at full blast and the sig-gen dial does nothing until I turn it way down and then the blower cuts out and wont go on again until the power plug is turned on and off again. With the blue wire on  "OV"  andthered  on  "0-10v"  the motor just starts  to run and then cuts out.

Something doesn't seem right. Thoughts?

Edited June 13, 2018 by Eric Dennis

[Vern Wimmer]

I'm no electric expert but I have a feeling you may need to move your higher command line to the higher output connection and your lower command line to the lower connection, where you have your high now. The thing I am more unsure about is whether the white should go to the "0v" connection.