Grinding ball mill structure
The grinding equipment widely used in the
mineral processing is the ball mill and the rod mill, At present, only the grid and
the overflow type are used in the ball mill.The cone ball mill is not
manufactured because of its low productivity.
Structure of grid ball mill
The structure of the ball mill of all kinds
of specifications is basically the same.Now we describe the structure through the model MQG2700x3600mm grid ball mill which manufacturered by
sinonine. Fig 1 is the general layout of MQG2700x3600mm grid ball mill manufacturered by sinonine
The barrel（1） of a ball mill is welded by a steel plate with a thickness of about
18-36 millimeters, Its ends are welded with steel flanges(2). The end cover (7)and
the hollow shaft neck end cover(12) are connected to the flange plate, the two must be precision processing
and coordination, because the shaft neck of the weight of the mill is welded on
the end cover. A manhole for repairing and replacing
the liner is opened on the barrel. The lining of the barrel is fitted with
liners which are
made by manganese steel, chrome steel, Wear-resistant cast iron or
rubber etc, Of which high manganese steel is widely used. The
thickness of the liner is about 50-130 mm, and there is a gap of 10-14mm between
the shell and the cylinder. It is made of plywood, asbestos pad, plastic board
or rubber shop, which is used to slow down the impact of the steel ball on the barrel. The
liner(3) is fixed on the barrel with bolt (4)and rubber ring and metal
washer under the nut in order to prevent the leakage of the pulp.
(1) Barrel, (2)Flanges,(3)Liner,(4)Bolt,
(5)Human hole cover, (7)Hollow shaft neck end cover, (8)Joint feeder, (9)End
liner, (10)Bearing inner sleeve, (11)Dustproof cover, (12)Hollow shaft neck end
cover,(13)Grid type liner, (16)Center liner,(17) Bearing inner sleeve, (18)Big
gear, (19)Pinion , (20)Drive shaft, (21)Coupling
Liner
The
shape of the liner shown as fig 2 is divided into two types, such as the smooth
and the unsmooth.The smooth liner can be used
for fine grinding because of the larger sliding of the steel ball and strong
grinding and stripping，The unsmooth liner can cause the ball to fall from higher
place and it has strong agitation for both steel ball and mineral material, so
it is suitable for coarse grinding. At present, it has the tendency of long
strip liner, because it is simple to manufacture, no or less bolt
fixation, and it only needs to be pressed by the end cover liner or wedge
layering. It is easy to install, and it also reduces the leakage of slurry
along the bolt hole and improves the strength of the barrel.
（a）wedge shape (b) wave shape (c) Flat convex shape
(d)Flat
shape (e)stage shape
(f)Strip
shape (g) Rudder shape
(h) K-shape rubber liner （i）B-shape rubber liner
Fig2 The shape of the liners
The liners is a
vulnerable part of the ball mill. It is damaged by the impact and grinding of
the steel ball and ore, and the corrosion of the pulp during the work. The
service life of the liners
depends on the type of ore and the way of grinding,
usually about half a year to about one year. In order to improve the time limit
for the use of the lining, many studies have been carried out at home and
abroad. The test results showed that life can reach 3-4 times the steel liner rubber
lining the (more than twice as high as hard nickel alloy), and has low noise,
light weight, easy replacement.
A flat fan-shaped manganese steel liner is
laid on the inner side of the end cover at the end of the ore. The hollow shaft
is equipped with a shaft neck inner sleeve with an inner surface which is a
spiral blade. The inner sleeve can not only protect the axle neck from being
damaged by ore, but also send ore into the ball mill.The ore feeder is fixed to
the end of the inner sleeve of the shaft neck.
End cover
The end cover with a hollow shaft neck at
the end of the mine is equipped with a bearing inner sleeve and a grille.
Discharge lattice by lattice center liner, liner and dustpan shaped lining
board etc. Cast ribs with eight radial wall in the end cover, the end cover is
divided into eight fan rooms, each room equipped with dustpan shaped lining
plate and grid lining board. Dustpan shaped liner with screws
fixed on the end cover. Grid lining board currently has two kinds of structure
forms: one is the synthesis of a two block group, by wedge pressing, wedge iron
screw through the fastening ribs on the end cover, a center of center liner
spigot holds so they tilt and fall off. The other is to change the two pieces
into one piece and fix it with a screw. The holes on the lining of the grid are
tilted, and the width of the holes expands gradually to the end of the ore,
which can prevent the reflow of the pulp and the clogging of the coarse grain.
The center liner is star shaped, which consists of two blocks and is fixed on
the bar with screws. The pulp flows into the fan chamber through the pores on
the lining plate at the bottom of the row of ore. Then the slurry is
transferred to the upper part and discharged along the channel. The hollow
shaft neck is inlaid with a wear-resistant inner sleeve and a horn shaped blade
is made at one end of the neck of the shaft to guide the flow of the pulp to
the blade.
1.grid
liner 2.bearing sleeve
3.hollow shaft 4.dustpan
shaped liner 5.center liner
6.ribs 7.wedg
Fig 3 Discharge end cover of ball mill
Feeder
The ore feeder of a ball mill has (a)drum
type, (b)worm type and (c)combined type, and its structure is like Fig 4
The drum type ore feeder is cast by raw
iron or welded by steel plate. Conical. The inner wall of a spiral end
connected with the conical cover, baffle with fan-shaped holes is arranged
between the shell and the lid, aggregate through the baffle through the spiral
into the ball inside. It is used for open grinding.
The worm type feeder is a spiral spoon with a
replaceable spoon mouth. In order to put the scooping ore material into the
ball mill, a circular hole is opened at the center of its side wall, and the
ore is then sent through the hollow shaft neck inner sleeve to the ball mill.
The worm type ore feeder has a single spoon and double spoon form, which is
used for the second stage grinding machine of two section grinding.
Fig 4.Feeders of a ball mill
Main bearing
The main bearing of ball mill by self aligning sliding
bearing, the bearing seat is a concave spherical surface, Vanessa cast shaft
Babbitt, outer surface made of convex spherical, two spherical contact, avoid
the hollow axle neck and bearing formation of local contact. A cylindrical pin
is placed in the center of the sphere of the bearing seat and the axle bush to
prevent the slippery displacement from being too large to slip out of the
bearing seat. The bearing is lubricated by the thin oil centralized oil
station. The oil flows through the pump into four main parts and then enters
the main bearing and the transmission bearing. Then it goes to the oil drain
pipe at the bottom of the bearing and flows back to the oil tank. If necessary,
the cooling pipe is mounted on the bearing. For small or medium-sized mill,
using oil cup oil or self lubricating oil ring.
1.Bearing seat; 2.Bearing cover; 3.Bearing bush; 4.Babbitt
alloy layer; 5.Cylindrical pin; 6.Bolt;7.Discharge pipe; 8.Dustproof sealing
ring; 9.Felt pan
Fig 5.main bearing of ball mill
Drive the ball mill, with low speed synchronous
motor through the coupling to rotate the pinion gear, the gear meshing and
fixed in the shell and rotate the cylinder. To prevent dust from falling into
the gear pair, it is sealed with a dustproof cover. The small ball mill can be
driven by asynchronous motor and gear box.
I love this article, Learned a lot. thanks
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