This is Jason Gaber with Mt Baker Mining and Metals, and I wanted to do a video of operation
and maintenance of our hammer mills. This is a 16” x 12” hammer mill, and it’s
rated at between 1 and 2 tons per hour, depending on the screen size you put in at the bottom.
It’s powered with a 15 horsepower, 3-phase motor. And it can be run both dual voltage
at 60 hz and dual voltage at 50 hz, for some of our international customers. Ball door
also makes a 15 horsepower single phase motor that we’ve put on these machines as well,
for when 3-phase power is not available.
We send the units with fully-enclosed, OSHA approved belt guards, and we have a variety
of hoppers we can put on here. This customer is going to be feeding with a small conveyor.
It should be noted the rotation of the hammers and the shaft of the hammer mill, so as the
material is fed down into the mill, it gets thrown back against the case, and crushed
against the case, rather than if it’s spinning the wrong way, it’ll go right into the screen
and will wear out the screen much faster.
It’s important to have a fairly consistent feed rate with this mill, either shoveling
or metering in with a bucket, or meter with a conveyor.
The other thing with overfeeding, is if you start to see material, water, and crush material
coming out the holes between the shaft and the case, reduce the rate of feed. That material
can get in the bearings, and will wear the bearings out.
It’s recommend to run this mill wet, with water. It takes about 1-2 US gallons per minute.
Here’s a discharge chute coming out the bottom. It’s reversible, so it can be bolted
to this side as well.
We’ll take a look down the inside of this hammer mill. There are four rows of five hammers
in this version, so there are 20 hammers total. You can see our laser-cut screen here in the
bottom, that’s a 0.8 millimeter slot. It will produce material that’s 100% passing
at 20-mesh, and 50%-60% passing a 50-mesh screen. These hammers are high chrome content,
so they’ll last, depending on the material, if you’re running abrasive quartz, they’ll
last somewhere between 1 to 2 weeks. They’re reversible, so you can switch them around
once this face is worn out. To change the hammers, you take out the cauter pin, this
pin slides out right over the bearing, you can turn the hammers around and then replace
the pin.
These screens are welded in. To replace the screen, there’s a weld along here, a skip
weld in 1, 2, 3 places. Just grind it out with a grinder, roll the new screen in, weld
it up, and it should be good to go. It takes about half an hour to do, and needs to be
done every one to two hundred tons.
This mill has replaceable armor all around the bottom, bolted through to the outside
of the base. To change the armor you take out the bolts, knock that armor out, and then
replace it with the new stuff and bolt it back in.
Here’s a look up into the hood. Same thing, we have armor all the way around, top and
bottom, and sides. It’s really easy to replace, just take the bolts out, replace it with new
armor, and bolt it back in.
This machine needs to be greased here and here, once a day, a couple pumps of grease
in there to keep the bearings working properly. Those are the only two greased fittings on
this machine. Other things to check are the belts, take the cover off every once in a
while and check for tightness. Using this jacking bolt here, the belt tension can be
adjusted. So you loosen the motor mounts, adjust the tension with this jacking screw
here, and this one here. And when the belt’s tight, and then retighten the motor mounts.
When you first get the machine, run it for a couple hours then shut down and check the
tightness of the bolts and the belts. The belts will stretch a little bit during the
first couple hours of operation, and the bolts may need to be tightened up again as well.
We use nylock nuts so they shouldn’t come loose, but it’s always better to check after
the first couple hours and make sure everything’s still tight.
Here are a couple different sized screens we use for the 16 x 12” hammer mill. This
is a laser cut 0.8 millimeter screen like you saw installed in the mill. This is great
for miners because it produces a nice fine grind. This is the next step up, this is about
a 1.2 to 1.3 millimeters, and this screen is also good for miners. It produces a little
bit coarser grind, the throughput is increased, so this screen will do about 2,500 pounds
per hour. And we have an even larger screen here, this is between 2 and 3 millimeters,
it doesn’t grind as fine, but you get upwards of two tons per hour out of this size screen.
We’ve sold this coarser size screen to guys who are re grinding metallic slag, and some
of the soil-additive guys like a little bit coarser grind. Some of the fertilizer guys
and guys like that. So we’ve found some good application for some of these coarser
screens.
So thanks for watching, and if you have any questions for us about our hammer mills you
can give us a call or e-mail us, all which is in the description below. I’m interested
to hear what you think of the mills, so give us a call or email us, and we’ll catch you
in the next video. Thanks for watching.