Gyratory Crusher
Concave Liner
Installation
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved.
Concave Installation Overview
This is a basic explanation of the installation procedure for
gyratory concave liners.
Follow all original equipment manufacturer’s (OEM)
instructions and guidelines for installation and
maintenance where applicable.
This presentation is not intended as a substitute for OEM
or mine site procedures or for use as complete
instructions.
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 2
Top Shell Preparation
Remove any old backing on the top shell from previous
concave installations
Repair any defects on the concave/top shell mating
surfaces
Replace worn concave support ring segments
Apply a light application of release agent to the top shell
surface
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 3
Concave Backing
Backing material is used to fill the space
between the concaves and the top shell to
evenly distribute the crushing forces to the
top shell
Epoxy backing is the most common
material used, so this presentation does
not address use of molten zinc backing
Epoxy backing is available in standard and
high-impact formulas
The type of backing used must be determined
by the specific crushing application &
conditions
Clean the fit surface of the concaves by
sandblasting or a wire brush on a grinder
to remove dirt or excess rust to allow the
epoxy backing to bond to the concaves Concave Fit Concave
Surface Fit Pads
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 4
Lifting Concaves
Most concaves are supplied with
lifting eyes Lift Eye Lift Nut
Lift nuts are optionally included
on some concaves
A 1”-8 UNC eye bolt is threaded
into the concave for placement
Lift nuts can be used for concave
removal if they are sealed from
backing (e.g. filled with silicone, a
rag, etc.)
Lifting eyes are typically
removed after the concaves are
set and backed
For manganese concaves, lift eyes
can be torch cut flush
For alloy concaves, it is advisable
to use an abrasive cut-off wheel to
cut lift eyes off as close as
possible to the concave face
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 5
Concave Height
Determine the height of
horizontal joint spacing (gap) Concave
between rows of concaves if it is
not already known
Stack one concave from each row Top Shell
in the top shell and measure the Locking Lug
distance from the stack height of Horizontal
the upper concave to the required Joint Spacing
final installation height
Divide this distance by the number
of rows minus one to find the
spacing dimension between rows Top Shell
Most upper concaves have a top
shell locking lug to prevent
upward movement of the
concaves within the top shell
Make sure the final installation
height will place the lug at the
correct height
Concave
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 6
Concave Placement – Setting Ring
A concave setting ring is a
fixture that can be used to set
an entire row of concaves at
once
The concaves hang from and
are spaced evenly by the ring
If a setting ring is used, set and
brace the row of concaves tight
to the top shell
Shim the concaves, if needed,
so there is contact with the top
A setting ring is shown with hanging middle row concaves
shell at all fit pads being lowered into the top shell
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 7
Concave Placement – One at a Time
If concaves are placed
individually, wood cross braces
can be used to hold them tight
to the top shell
Initially, place the concaves
tight together with no vertical
joint spaces (gaps) between
Concave
them Fit Pads
This will allow sufficient space to
set the last concave in the row
Shim as needed so there is
contact with the top shell at all
fit pads
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 8
Spacer Dowels
Insert a spacer dowel into the dowel
slot in each concave vertical joint (gap)
Spacer
Dowels Tap the dowels down to evenly space
the concaves
Manganese concaves are designed to
have gaps 3/8 to 1/2-inch wide
Alloy concaves are designed to have gaps
1/4 to 3/8-inch wide
Smaller gaps are acceptable with alloy
concaves and, in some cases, zero gap
spacing may improve wear performance
Once the vertical joints are even, tap
dowels tight to lock the concaves in
position
Trim the spacer dowels even with the
top of the row of concaves
Spacer dowels are intentionally made long
to allow for variation in vertical gap
requirements
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 9
Seal Concave Joints
Seal the face of each
vertical joint (gap)
between concaves
with plaster or similar
material to prevent
backing from leaking
out
Seal each horizontal
joint at the base of
each concave
Be sure to seal only
the face of each joint
so that they can fill as
much as possible with
epoxy backing
Sealed Joints
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 10
Pour Backing
Follow the directions for mixing the two-part epoxy backing
Make sure the backing is thoroughly mixed to the bottom of the buckets
Mix only enough backing for one row at a time
Working time and cure time for the backing will be shorter with higher
ambient temperatures
Pour the backing to approximately ¾ of the row height
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 11
Additional Rows
Set additional concave rows
using the same procedure
Maintain the previously
determined horizontal joint
spacing between rows
Stagger the vertical joint
locations as shown
Pour top row backing to the top
of the concaves
Remove the lifting eyes
Copyright 2013 Columbia Steel Casting Co., Inc. All rights reserved. 12
