Squirrel cage blower type drywasher questions

[Gelmac]

Curious minds question : some say that an old style dry blower using the (squirrel cage blower) like the picture bellow isn't effective and prefer a gas blower type, due to added hot air which helps dry off the dirt (if it have some moisture in it). Where I go , there is no rain whatsoever , rarely there are any drops, so the grounds remains dry as bone
IMO using what you have instead of buying something new, is better to start off, in this case a (squirrel cage blower) is available locally , used in making evaporative water air conditioning units. A gas blower (or leaf blower for that matter) on the other hand must be imported from overseas , probably China as the norm here.
So what you dry washing experts say in terms of technical abilities of this type of dry washers? ole timers used what they got their hands on, but now with availability of small gas engines , no longer this air blowing devices are used nowadays. What the good setup if any one has made or saw one of this in action? CFM wise?Motor placement? efficiency of recovery?
I know there are some posts that touched this theme on the forums before, but they didn't got further into it.

a flash from the past pics (retrieved from the internet):

 

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[snakejim]

There is and old dry washer at our museum that was built about 1936 in California. It is hand cranked using old sprockets and a linked chain drive off of old farm equipment and has a squirrel caged blower plus the riffle tray oscillates. Personally I think the bellows system is better, lighter, and is a lot easier to build. I built a bellows dry washer 35 years ago and it still works great to this day.
Here's a link to a magazine article of a fellow I knew many years ago who was an Icon around 29 Palms, California: http://mydesertmagazine.com/files/197602-DesertMagazine-1976-February.pdf
The article on dry washing starts on page 28.

 

[russau]

WOW! Thanks Jim for the trip back in time!

 

[snakejim]

WOW! Thanks Jim for the trip back in time!

You're welcome russau!

Gelmac, here's a link to plans for one you can build yourself:
Gold Prospecting and Nugget Hunting is what We do!

 

[Clay Diggins]

The pulsing action of a bellows unit is the sorting mechanism. The vibration of a gas blower is the sorting mechanism. Most gas blowers don't add any appreciable heat energy to the air.

A squirrel cage blower is the most efficient at blowing a large volume of air but there is no variation to create sorting. Just blowing doesn't really cut it with a drywasher. The squirrel cage design has very little air pressure potential compared to a bellows or gas blower. Air volume is not the same as air pressure.

I prefer a bellows design but if you are looking to move real volume without huge machinery the gas blower with a vibrating assembly is your best bet, all else being equal.

Heavy Pans

 

[Gelmac]

You're welcome russau!

Gelmac, here's a link to plans for one you can build yourself:
Gold Prospecting and Nugget Hunting is what We do!

Hey Jim ! thanks for the links , the one in the mag looks very old indeed. As I said miners use what they can get around, so no wonder they used squirrel cage blower ! As technology progresses and building materials advance we see something that ole timers didn't dream of ! Like using air craft building materials, light weight and strong enough to take a beating, yet functional to a more production amounts of gravel/dirt.

 

[Gelmac]

There is and old dry washer at our museum that was built about 1936 in California. It is hand cranked using old sprockets and a linked chain drive off of old farm equipment and has a squirrel caged blower plus the riffle tray oscillates. Personally I think the bellows system is better, lighter, and is a lot easier to build. I built a bellows dry washer 35 years ago and it still works great to this day.
Here's a link to a magazine article of a fellow I knew many years ago who was an Icon around 29 Palms, California: http://mydesertmagazine.com/files/197602-DesertMagazine-1976-February.pdf
The article on dry washing starts on page 28.

Jim, do you have any picture of your home built drywasher or the one in your local museum? would be interesting to see such a historical item.

 

[Gelmac]

The pulsing action of a bellows unit is the sorting mechanism. The vibration of a gas blower is the sorting mechanism. Most gas blowers don't add any appreciable heat energy to the air.

A squirrel cage blower is the most efficient at blowing a large volume of air but there is no variation to create sorting. Just blowing doesn't really cut it with a drywasher. The squirrel cage design has very little air pressure potential compared to a bellows or gas blower. Air volume is not the same as air pressure.

I prefer a bellows design but if you are looking to move real volume without huge machinery the gas blower with a vibrating assembly is your best bet, all else being equal.

Heavy Pans

Good info, Clay Diggins. Why not use a vibration mechanism e.g vibrating motor to underneath the sluice to help in sorting material? It's not hard to do besides if the blower using electric drive it can be easily get the power in a form of 12v source (may be?). I see on some models of drywashers they added a vibrating motor to the feed hopper to help in the screening process instead of raking the oversize material by a shovel for example.

I also prefer the puffer type, quite/less dust and can be run with a battery/solar panel which is more suitable in the desert. Of course one needs to figure out how to scale it up if volume of material is the target. I remember I've had seen larger bellows.puffer type of drywashers on this one forum, run by 110/230 v motors.

 

[snakejim]

Jim, do you have any picture of your home built drywasher or the one in your local museum? would be interesting to see such a historical item.

I'll see if I have time to take and post some photos. Been real busy lately.

 

[Gelmac]

This guy has plans to make a blower type drywasher using the squirrel cage part, the small picture on my first post on this thread is from his website .
http://www.havasugold.com/toppage 1.htm

 

[hvacker]

Gelmac, the blower in your picture is most likely from a furnace due to it's size. That type of direct drive fan will cavatate when the outlet is restricted meaning the output will fall off. These fans often have variable speed motors but not always. A fan of this type but with a belt drive will deliver more air as there is less slippage in the motor's magnetic field.

I don't know how you'd accomplish the sorting that was talked about. You might be able to construct a damper arrangement on the outlet that could be varied or pulsed.
If you want to build this system you could go to a hvac contractor and ask if they have any used furnaces they were going to toss and rescue a fan. Some will collect a bunch and then scrap them.

 

[Gelmac]

Gelmac, the blower in your picture is most likely from a furnace due to it's size. That type of direct drive fan will cavatate when the outlet is restricted meaning the output will fall off. These fans often have variable speed motors but not always. A fan of this type but with a belt drive will deliver more air as there is less slippage in the motor's magnetic field.

I don't know how you'd accomplish the sorting that was talked about. You might be able to construct a damper arrangement on the outlet that could be varied or pulsed.
If you want to build this system you could go to a hvac contractor and ask if they have any used furnaces they were going to toss and rescue a fan. Some will collect a bunch and then scrap them.

hvacker ,thanks for the head up . Unfortunately we don't have many of these contractors around here. But I will seek another source. May be if I weld a nut on the inside of the fan, that will provide the vibration (pulsing) action which may help in the sorting process? Then again the problem with these type of fans is they lose pressure if they were reduced in the output. Seems the Aussies have manged to make it work somehow !

This guy made one out of a squirrel cage blower fan :