Ceramic brick

An undeformed weldable insert is inserted into an undercut recess opening at an inner face of an abrasion resistant ceramic brick and thereafter deformed into the undercut and interlocked with the brick. The insert is then welded to a substrate either by inserting a welding rod through a small guide hole into the recess from the abrasion resisting outer surface of the brick and then into guided welding contact with the substrate through a hole in the insert, or by inserting the welding rod through a hole in the substrate opposite the insert. Alternatively the inner face of the brick is overlaid with a fluid hardenable plastic that fills and interlocks with the undercut recess to provide means for bolting or cementing the brick to a substrate to be protected.

CERAMIC BRICK 
The present invention relates to improvements in a ceramic brick of the 
type used for providing an impact and/or abrasion resistant lining for a 
load supporting surface to be protected, to improved means for securing 
such a brick to the surface, and to improved methods for manufacturing 
such a brick and for securing the same to the surface, which may comprise 
by way of example the wall of a pipe or a chute exposed to abrasion, or 
surface portions of a military vehicle exposed to shrapnel or small arms 
fire. 
BACKGROUND AND OBJECTS OF THE INVENTION 
It is conventional in industries involving the transportation or storage of 
abrasive materials, such as coal, various mineral ores, or other 
abrasives, to provide a steel backing or liner for the wall or surface to 
be protected, and thereafter to weld specially prepared abrasion resistant 
ceramic tile or bricks to the backing. 
Such bricks are commonly one inch thick fired silicon ceramic, such as an 
aluminum-silicon oxide or a silicon carbide compacted under high pressure 
from a dry powder and optionally with a suitable binder. The typical brick 
has four by six inch faces, although the dimensions may vary appreciably, 
say from one-half to two inches in thickness, with faces ranging from less 
than four inches in the shorter dimension to more than nine inches in the 
longer dimension. Also the brick may be molded from a molten abrasive 
resistant material such as basalt or an aluminum-zirconium-silicate. 
A common weldable brick is formed with a central welding hole about one 
inch in diameter that extends through an outer face of the brick and is 
constricted slightly adjacent to the opposite inner face to confine a 
weldable metallic insert. The latter is inserted into the larger or 
unrestricted opening of the welding hole and is retained adjacent to the 
restricted end by friction. With the welding insert arranged coaxially in 
the hole, the metal insert is welded to the steel backing or liner, either 
by conventional MIG (metal inert gas) welding or in rare instances by 
conventional use of an arc welding rod. Thereafter a cylindrical closure 
plug is inserted into the unrestricted opening of the welding hole to 
close the same. 
In some instances, it is preferable to weld the metal insert by 
conventional arc welding to the steel backing or liner, but arc welding is 
not particularly convenient with the type of brick described because it is 
difficult to maintain the metal welding insert in a coaxial position at 
the reduced end of the hole. The welding insert is provided with a central 
opening through which a welding rod or wire must pass in order to contact 
the steel wall or backing. When the welding rod is extended through the 
aforesaid central opening in the welding insert, the latter is frequently 
knocked out of alignment by the rod and welded in a cocked position to the 
steel liner. A similar problem arises even during MIG welding when the MIG 
welding wire is inserted through the welding insert into contact with the 
steel backing or liner to which the brick is to be secured. 
Not only will the resulting weld be less secure, but the cocked insert in 
some instances prevents the cylindrical closure plug from fitting flush 
with the outer surface of the brick. The plug will thus be subjected to 
excessive abrasion and will rapidly wear away. Furthermore, although the 
cylindrical plug is usually cemented within the welding hole, it 
frequently works loose even when it is flush with the outer surface of the 
brick, whereupon the metallic insert will rapidly wear away by the 
abrasive action and the entire brick will be dislodged. 
Even if the metallic insert is properly located and welded to the steel 
backing, the cylindrical closure plug cannot extend axially within the 
welding hole to the extent desired because a certain amount of space must 
be allowed to accommodate the situation when the metallic insert is cocked 
out of its coaxial alignment within the hole. Accordingly, the wear 
resistant thickness of the brick at the region of the approximately 
one-inch diameter welding hole will be considerably less than the 
thickness of the adjacent portions of the brick. When the thinner 
cylindrical plug eventually abrades away, the metallic welding insert is 
rapidly disintegrated by abrasion at the exposed hole. 
In addition, the one inch centrally located hole tends to weaken the brick 
across the diameter of the hole. In consequence, the comparatively brittle 
ceramic brick tends to break when subjected to impact during use, or when 
the installer of the brick attempts to break off a portion in order to 
provide a close fit near the edge of the wall to be lined. In that event, 
the brick tends to crack at the middle through the one inch hole instead 
of at the region where the craftsman's hammer strikes the brick. 
An additional objection to bricks of the type described is that three loose 
pieces are required, i.e., the brick, the insert, and the cylidrical plug. 
The insert may be cemented in place, but the cementing involves an 
additional operation and increases the cost of the brick. 
Important objects of the present invention are to provide an improved brick 
of the general type described and a method of using it that avoid the 
above noted objections; and in particular to provide an improved weldable 
ceramic brick having an insert receiving recess opening at its inner face, 
i.e. the face that confronts the wall or substrate to be protected, to 
receive a deformable weldable insert, which after being inserted into the 
recess through its opening at the inner face of the brick, is deformed 
into undercut portions of the recess by force applied against portions of 
the insert exposed at the latter opening, thereby to frictionally and 
mechanically interlock the insert and brick. 
Another important object is to provide a weldable brick where, instead of a 
one-inch hole extending approximately through the entire brick, only a 
small diameter guide hole large enough for insertion of a welding wire as 
customarily used in MIG welding, or a slightly larger diameter guide hole 
for a conventional arc welding rod, extends centrally through the brick 
from its outer face toward its inner face. 
The guide hole may be as small as approximately 0.035 inches in diameter 
and no larger than one-eighth of an inch in diameter where MIG welding is 
available, or may be approximately three-sixteenths of an inch in diameter 
if it is required for guiding a conventional arc welding rod, and may 
extend about three-quarters of an inch into a one-inch thick brick from 
its outer face, whereupon the guide hole enlarges radially to a maximum of 
approximately a square inch in cross sectional area to provide a recess 
having an insert receiving opening at the aforesaid inner face of the 
brick and having a plane ceiling normal to the axis of the guide hole and 
parallel to the inner and outer faces of the brick. The periphery of the 
recess adjacent to its ceiling is undercut into the sidewalls of the 
recess to provide a larger cross sectional area than the insert receiving 
opening at the inner face of the brick. Thus the maximum radial or 
transverse dimension of the recess comprises an enlargement or an undercut 
with respect to the aforesaid insert receiving opening for receiving edge 
portions of a sheet steel welding insert. 
A one-piece metallic welding insert is provided with a plane base having a 
central hole coaxial with and sufficiently larger than the guide hole 
through the brick to enable free passage of a welding wire or rod. The 
base also has diverging prongs or outer edge portions that define an area 
approximately the same as the area of the insert receiving opening, but 
slightly less to enable insertion of the insert freely into the recess 
through that opening. The prongs or outer edge portions are dimensioned so 
that when the insert is inserted, prongs first, through the insert 
receiving opening, and the base of the insert is pressed toward the 
ceiling of the recess, the prongs will slidably engage the ceiling and be 
deformed radially or transversely of the guide hole into the undercut 
portion of the recess. Thus the insert will be interlocked rigidly within 
the brick. At the interlocked position, the plane of the base of the 
insert will be spaced sufficiently from the inner surface of the brick and 
within the recess to enable formation of a pool of molten welding rod 
between the base and the steel backing for the chute or other wall to be 
protected. 
In a modified form, a metallic insert has its deformable outer edge 
portions generally square in section transverse to the guide hole. The 
insert receiving recess is also square in cross section to closely receive 
the insert and is undercut adjacent to its ceiling to receive the corners 
of the square edge portions when the insert is located within the recess 
and rotated 45.degree.. In this situation the corners of the square edge 
portions prior to the rotation decline slightly away from the ceiling. 
Thus when the insert is rotated, the edge portions are deformed or bent 
upwardly toward the ceiling by cam action as they enter the undercuts. The 
resulting deformation of the insert frictionally interlocks it within the 
recess. The central hole in the base of the insert and coaxial with the 
guide hole is preferably out-of-round for receiving a mating tool to 
enable rotation and interlocking of the insert within the recess. 
After the metallic welding insert is deformed and interlocked within the 
recess, the brick may be shipped as a weldable unit to the site where 
welding is desired. The brick is then held with its inner face adjacent to 
the steel wall or backing to be protected and welded in place by 
conventional MIG or arc welding. A conventional welding rod or MIG welding 
wire is inserted through the small guide hole in the brick and thereby 
guided through the coaxial hole in the base of the welding insert and into 
welding contact with the steel backing without touching the insert. 
The weldable brick described is particularly suitable for conventional arc 
welding because the small diameter guide hole guides the arc welding rod 
coaxially through the larger hole in the base of the welding insert and 
into welding contact with the steel liner without disrupting the coaxial 
alignment of the insert. The heat of the arc melts the tip of the welding 
rod which flows into contact with both the base of the insert and the 
steel backing to complete the weld. However where MIG welding equipment is 
available, the brick described can also be readily welded similarly to the 
steel backing by conventional MIG welding. 
By virtue of the improved construction comprising the deformed welding 
insert frictionally and mechanically interlocked within the undercut 
recess, the insert cannot be inadvertently pushed out of its alignment 
within the recess and a weld of optimum strength and effectiveness is thus 
readily accomplished. Welding the brick at any angle of support to the 
steel backing and especially overhead is facilitated with consequent 
reduced welding time and labor cost. After the weld, the small diameter 
guide hole through the brick may be sealed with a caulking material, but 
such caulking is not essential because the hole is too small to cause 
serious damage to the brick by abrasive material moving across its outer 
surface. Also by virtue of the undercut recess for the welding insert, 
occupying approximately only one-forth of the thickness of the brick, the 
major thickness of the brick is available for resisting abrasion and the 
abrasion resistant life of the ceramic brick is materially increased. 
Likewise a plane of weakness through the diameter of the recess for the 
welding insert is minimized because that recess only extends approximately 
one-forth of the thickness of an inch thick brick, whereby the latter can 
be hammer cut to a desired size by a craftsmen without breaking the brick 
through the recess. 
In a typical construction, the small diameter guide hole for the welding 
rod and the recess for the welding insert is formed while the brick is 
soft, i.e. during its initial formation by conventional molding processes, 
especially when the recess for the welding insert is formed with a 
rectangular cross section. Conventional cam operated die parts can then be 
used to form the undercut recess and thereafter retracted from the molded 
brick. The brick can also be molded with only the guide hole for the 
welding rod or wire extending therethrough. Thereafter, while the brick is 
still soft and before being fired, an undercut insert receiving recess may 
be cut in the inner face of the brick coaxially with the guide hole. In 
either case, after the brick is formed to the desired shape for receiving 
the welding insert, it is fired and hardened by conventional processes. 
Another object of this invention is to provide an improved weldable brick 
comprising the inserted, deformed, and interlocked welding insert 
substantially as described, and a method of using the same wherein the 
guide hole may be eliminated in situations where welding access to the 
exterior of the sheet steel wall or substrate to be protected is 
convenient. In such a situation, a hole is burned or otherwise formed 
through the sheet steel wall from its outside, i.e. its surface opposite 
the surface to be protected. The latter hole is dimensioned to enable 
insertion of a welding rod or MIG welding wire and is located coaxially 
with the center of the welding insert in the brick. Thereafter the welding 
rod or wire is inserted through the hole in the steel wall and into 
contact with the edges of the latter hole to form a molten pool joining 
the steel wall and metallic insert interlocked within the brick as 
described above. Also in the situation described, the base of the metallic 
insert need not be provided with a central hole for passage of a welding 
wire or rod. 
Another object of this invention is to provide weldable bricks of the type 
described but dimensioned for lining a pipe used for conveying an abrasive 
slurry or pneumatically transporting abrasive particulates. It has been 
conventional to line such pipes with abrasion resistant ceramic bricks 
extending longitudinally of the pipe and having truncated triangular cross 
sections arranged to fit closely together adjacent to the pipe's inner 
periphery. Commonly the bricks would be cemented in place, as for example 
by forcing cement longitudinally of the pipe within the chordal space 
between the pipe and each adjacent brick. The cementing often causes small 
amounts of cement to enter spaces between the bricks, so that the space 
for the last brick can seldom be predetermined. 
When all but one of the bricks are installed around the interior 
circumference of the pipe, the remaining space is filled by a key brick 
that locks all of the others in place. In order to assure a tight fit for 
the key brick, it is frequently diamond cut to size and then hammered into 
place, an expensive and time consuming procedure. Furthermore, during use 
of the pipe, the abrasive slurry rapidly wears away the cement between the 
bricks, such that the key brick sometimes loosens and falls out, whereupon 
the remaining bricks associated with the loosened key brick also fall out 
of place. 
In many instances where the pipe is used for conducting an abrasive slurry, 
only a lower portion of the pipe is in contact with the slurry. 
Consequently the expensive ceramic lining for the upper portions of the 
pipe, required only because of the key brick, are not used unless the pipe 
line is disassembled and the individual pipes are rotated at least 
approximately 120.degree., then reassembled. 
In accordance with the present invention, ceramic bricks shaped overall in 
accordance with conventional practice, but provided with welding inserts 
as described, are welded to the inner periphery of the pipe. Thus a key 
brick is rendered unnecessary and, where feasible, only approximately the 
lower half of the pipe is lined with the ceramic bricks, with obvious 
savings in material and labor. Where the type of use requires the entire 
interior circumference of the pipe to be lined, this is readily 
accomplished, but a tight and precise fit for the final or "key" brick is 
unnecessary and the expense of diamond cutting is avoided. Likewise no 
cement that can readily be abraded away is required to secure the bricks 
in place, but where cement is used, its abrasion causes no concern because 
the bricks are secured in place by welding. 
In many instances, the abrasive material is highly corrosive, such that 
metallic pipes or steel walls cannot be employed, even when lined with 
abrasive resistant bricks as described herein. In such instances the walls 
and pipes are manufactured from dielectric corrosion resistant materials 
to which the weldable bricks cannot be welded. It is accordingly another 
object of this invention to modify such walls or pipes to enable their use 
with the weldable bricks of the present invention. 
Specifically, weldable grommets or buttons made from corrosion resistant 
material, such as stainless steel for example, are secured within the side 
walls of the wall or pipe at locations coaxial with the welding inserts of 
the bricks. Thereafter the welding inserts are welded as described above 
to the grommets or buttons by otherwise conventional welding technique. 
The art involving the molding and firing of ceramic material from which 
bricks embodying the present invention are made is highly developed and 
capable of manufacturing weldable bricks as described having undercut 
insert receiving recesses of various shapes and sizes in accordance with 
this invention. The brick may be compacted from a dry powder within a 
multiple part mold under approximately 3500 psi (pounds per square inch) 
to produce a green unfired brick containing recess forming inserts that 
when removed leave the desired recess. However the forming mold for the 
green unfired brick can be complex and may require a number of recess 
forming mold inserts. 
Another important object of this invention is to provide an improved 
weldable brick of the type described wherein the recess forming inserts 
can be readily removed from the comparatively soft and friable green brick 
without damaging it immediately after it is compacted. The resulting 
insert receiving recess is undercut at its opposite ends, but the undercut 
at each end is offset laterally from the offset at the opposite end. 
At each end of the recess laterally of the undercut at the same end, the 
recess is defined by an end wall that slopes endwise toward the ceiling 
from its respective end of the recess opening for approximately 20% or 
less of the length of the recess, then merges with the recess ceiling. The 
recess is formed by placing a pair of identical independently removable 
recess forming inserts side-by-side in the mold. Each removable insert 
forms a lateral half of the recess, i.e. one lateral portion of the 
ceiling spacing one sloping wall and the one undercut at the opposite ends 
of that lateral half. After the powdered material of the brick is 
compacted under high pressure, each separate recess forming insert is 
withdrawn from the undercut formed thereby and moved outwardly of the 
recess as enabled by the associated sloping wall. Thereafter the green 
brick is fired and hardened. 
The weldable insert is preferably formed from a sheet steel blank to 
provide legs at its opposite ends dimensioned to fit within the opposite 
undercuts of the recess when deformed therein. In its undeformed 
conditions, it may be generally V-shaped and is readily insertable through 
the recess opening, with its legs diverging outwardly at approximately 
110.degree. from a central apex of the V toward the recess ceiling. Once 
inserted, pressure flattens the apex toward the ceiling and thereby forces 
the opposite ends of the legs into interlocking engagement within the 
undercuts. The weldable insert may or may not be provided with a central 
opening for passage of a welding wire or rod, depending on whether or not 
the brick is to be welded to a supporting wall from the outer face of the 
brick opposite the recess opening. 
The concept of the weldable brick having an undercut recess opening at its 
inner face an a weldable insert deformed and interlocked within the recess 
also enables other useful abrasion and shock resistant structures that do 
not require welding. It is accordingly another important object of the 
invention to provide recessed bricks as described herein interlocked with 
either a thermosetting or thermoplastic sheeting or surface without 
recourse to welding. In one embodiment by way of example, a number of 
ceramic bricks as described herein are placed outer-face down on the 
surface of a temporary supporting mold or frame having a peripheral raised 
border. Thereafter a hardenable liquid plastic, reinforced as for example 
by glass fibers if desired, is poured over the upwardly opening recesses 
in the inner faces of the bricks to any desired thickness, say one-quarter 
inch to an inch or more. The plastic readily fills the recesses and 
interlocks with the metal welding inserts and, when hardened and removed 
from the supporting frame, provides an abrasion and bullet resistant panel 
or structure. The term "plastic" as used herein includes any suitable 
thermoplastic or thermosetting plastic, including various suitable resins, 
such as epoxy resins. 
The various ceramic bricks may be rectangular or hexagonal in shape for 
interfitting closely with each other, or may be of any desired shape if 
such interfitting is not important. The surface of the supporting mold or 
frame may be shaped so that the resulting abrasive resistant panel or 
structure will conform to any desired surface to be protected, such as a 
chute for abrasive materials, or surface portions of a military vehicle. 
When the abrasion resistant panel is other than flat, the surface area of 
the ceramic bricks may be comparatively small so that adjacent bricks may 
conform to various curvatures. Likewise when necessary the panel may 
obviously be formed between opposing mold parts according to conventional 
molding practice. 
Finally, abrasion or shock resistant panels or structures may be formed as 
described above without recourse to the above described weldable inserts, 
merely by emphasizing the undercuts of the recesses in the ceramic bricks. 
The fluid hardenable plastics will fill the recesses and interlock within 
the undercuts when hardened. 
Other objects of this invention will appear in the following description 
and appended claims, reference being had to the accompanying drawings 
forming a part of this specification wherein like reference characters 
designate corresponding parts in the several views. 
THE PRIOR ART 
The following patents represent the state of the art as known to applicant. 
Re. 22,108 Crecca 
3,624,344 Kutzer 
3,687,093 Byrd, Jr. 
3,747,291 Perigo et al 
4,520,601 Stacey, Jr. 
Crecca is not concerned with a weldable ceramic brick but shows a ferrule 
17 and screw 16 insertable through the upper side of an opening 14 into 
contact with a metal strip 10 to which the bolt 16 is welded. 
Kutzer is concerned with applicant's problem, but he illustrates the 
conventional art of inserting the retainer 8 into a comparatively large 
outer opening restricted at the inner face of the brick to hold the 
retainer 8 in place for welding to the steel plate 4. 
Byrd, Jr. and Perigo similarly insert weldable retainers into comparatively 
large openings through the outer surface of the brick for welding to the 
steel plate at a restricted inner end of the opening. These patents also 
disclose the concept of filling the outer surface of the brick with a 
closure plug, which as noted above is subject to several objections. 
Stacey, Jr. is not concerned with the provision of a ceramic brick having a 
weldable insert deformed into an undercut from the inside of the brick, 
but it shows a comparatively small diameter passage 22 opening into a 
recess 24 for the securing means. Like the above noted patents, it is 
otherwise not concerned with the concept of inserting and deforming a 
weldable metallic insert into an undercut recess opening at the inner face 
of a ceramic brick.

It is to be understood that the invention is not limited in its application 
to the details of construction and arrangement of parts illustrated in the 
accompanying drawings, since the invention is capable of other embodiments 
and of being practiced or carried out in various ways, and that the 
phraseology or terminology employed herein is for the purpose of 
describing the invention claimed in the appended claims. 
DESCRIPTION OF THE INVENTION 
Referring to FIGS. 1-3, an aluminum oxide ceramic brick 10 of approximately 
one-inch thickness is illustrated having approximately four-inch by 
six-inch rectangular outer and inner parallel faces 11 and 12. A small 
diameter guide hole 13 for a welding rod 22 extends normally through the 
face 11 at a central location for approximately three-quarters of an inch 
and enlarges radially to provide a plane ceiling 14 of approximately one 
square inch for a recess 15. From the outer periphery of the ceiling 14, 
the side walls 16 of the recess 15 converge conically and coaxially with 
guide 13 at approximately a thirty to forty-five degree angle to an insert 
receiving opening through face 12 into the recess 15. 
A welding insert 17 may be formed from a mild steel or low carbon twelve 
gauge sheet steel blank to provide a plane annular base 18 having a 
central opening 19 of somewhat larger diameter than the diameter of the 
guide hole 13, and a plurality of diverging fingers or prongs 20 extending 
toward the ceiling 14, FIGS. 1-3. The prongs 20 in the undeformed 
condition shown in FIGS. 1 and 2 are dimensioned to pass with the base 19 
readily through the insert receiving opening into the recess 15 and into 
sliding engagement with the ceiling 14. The prongs 20 are dimensioned so 
that upon the application of force urging the base 18 toward the ceiling 
14, their outer ends will engage and slide along the extremely hard 
surface of the ceiling 14 and be deformed radially outwardly into the 
maximum diameter of the undercut recess 15, FIG. 3, without appreciably 
scratching the hard material of the ceramic brick 10. The insert 17 will 
thus be mechanically interlocked rigidly with the brick 10, and the base 
18 will be spaced from the surface 12 within the recess 15 approximately a 
sixteenth of an inch to prevent being grounded by contact with the wall 21 
until a molten pool 23 of welding rod material is formed to connect the 
base 18 and wall 21. The term "rod" as thus used and hereinafter will 
encompass elongate welding materials such as an electrically charged 
welding rod or wire used respectively in conventional arc of MIG welding. 
As described above, the assembled brick 10 and welding insert 17 may then 
be shipped to the location where it is intended to be welded to the steel 
wall 21 or other backing to be protected from abrasion. At the welding 
site, the brick 10 is placed with its inner face 12 adjacent to the wall 
21. A welding rod 22 is then inserted into the guide hole 13 and guided 
thereby coaxially through the opening 19 and into contact with the steel 
wall 21 without touching the insert 17. The arc welding operation is then 
carried out conventionally, such that the heat of the arc melts the end of 
the rod 22 in contact with the electrically grounded wall 21 and forms a 
pool of molten welding material 23 that hardens to provide a welded bond 
between the base 18 of the insert 17 and the wall 21. 
FIGS. 4-7 illustrate a modification of the present invention wherein the 
recess 24 in the ceramic brick 10 is essentially square or rectangular, 
FIG. 4, and if rectangular is provided with undercuts 25 along the 
opposite shorter ends, such that the long dimension of the ceiling 26 of 
the recess 24 is aligned with the long dimension of the brick 10. 
Similarly to the modification illustrated in FIGS. 1-3, the end walls of 
the recess 24 converge from the undercuts 25 at approximately a thirty to 
forty-five degree angle from the ceiling 26 to within approximately 
one-eighth of an inch from the inner face 12, then extend essentially 
normally to that face (except for a small draft angle required to 
facilitate removal of the mold parts) to an approximately one square inch 
insert receiving opening into the recess 24 through the inner face 12. The 
aforesaid draft angle for the various embodiments illustrated herein will 
be nominal because immediately upon release of the molding pressure 
required to form the green brick, the newly formed and unfired brick will 
expand slightly to facilitate removal of the recess forming mold part or 
inserts. 
The welding insert 27 may also be formed from a sheet metal stamping of the 
same material and thickness as the insert 17, and is formed with prongs 28 
at opposite ends dimensioned to be readily inserted into the recess 24 
into sliding abutment with the ceiling 26. Thus when the base 29 of the 
insert 27 is forced into the recess 24, the outer ends of the prongs 28 
will slide along the ceiling 26 and be deformed into the undercuts 25 
adjacent to the ceiling 26. In this regard, the outer portions of the 
prongs 28 may flare outwardly to faciliate their bending into the 
undercuts 25 with minimum stress at the junction of the prongs 28 with the 
base 29. 
In other respects the structure and operation of the modification shown in 
FIGS. 4-7 are esentially the same as described in regard to FIGS. 1-3. The 
base 29 is provided with a central opening 30 coaxial with and somewhat 
larger than the guide hole 13 and reinforced by upturned lateral flanges 
31 along the longer edges of the insert 27. When the insert 27 is finally 
deformed and interlocked with the brick 10, FIG. 7, the base 29 will be 
spaced within the recess 24 from the inner face 12 to the same extent that 
the base 18 is spaced from that face, thereby to enable the same welding 
procedure as described above. 
The structure of FIGS. 1-3 will be used where a recess 15 of circular 
section is desired. The recess 15 may be readily carved while the brick 10 
is still soft. Thereafter the brick is fired and hardened. The structure 
of FIGS. 4-7 is usually preferred where it is desired to mold the recess 
24 by means of a multiple part die simultaneously with molding of the 
brick 10. Such a mold will be more complex than a mold required merely to 
shape the brick 10 and provide the small diameter guide hole 13, but will 
enable the formation of a more economical brick 10 in large quantities 
because the operation of cutting a conical recess 15 is avoided. 
Additionally, the rectangular recess 24 can be dimensioned to enable 
removal of lesser amounts of the brick across the small dimension of the 
recess 24 and thereby further minimize impact breakage. 
FIGS. 8-11 illustrate simplified modifications of the invention where the 
forces tending to bow or bend the sides 31 of the insert 27 are 
comparatively small during use of the brick 10 in an abrasive environment. 
The insert 35 illustrated in FIGS. 8-9 is very efficient and easily 
manufactured and installed with the brick 10. In general, the brick 10 and 
its cooperation with the insert 35 are substantially as described above. 
The insert 35 may comprise a V-shaped stamping, rectangular in plan view 
and of the same material and thickness as the inserts 17 and 27. It is 
dimensioned in its undeformed condition to be inserted into the recess 24 
through the rectangular insert receiving opening defined at the inner face 
12 by the essentially vertical end walls 36 and side walls 37 of the 
recess 24. The legs of the stamping 35 diverge from the apex of the V at 
approximately 110.degree.. After its insertion, the insert 35 is deformed 
by the application of force against the base 34 of the V in the direction 
toward the ceiling 26, thereby forcing the opposite ends of the insert 35 
into the undercut portions 25 at the opposite ends of the recess 24. 
The end walls of the undercuts 25 are rounded primarily to facilitate 
molding of the recess 24. The wall outer portion 38 of each undercut 25 
diverges from the ceiling 26 at approximately a 20.degree. angle to meet 
the essentially vertical end wall 36 at a location spaced from the surface 
12 by at least approximately two hundredths of an inch and preferably not 
more than an eighth of an inch. Thus, when the insert 35 is forced into 
its interlocked position with the brick 10, its opposed ends will rest 
upon solid portions of the inclined surfaces 38, thereby to avoid chipping 
of the material of the brick 10 adjacent the insert receiving opening in 
face 12. 
In the deformed condition, the V bottom 34 of the insert will be spaced 
approximately a sixteenth of an inch from the plane of the inner face 12 
so as to readily contact the molten welding rod material and complete a 
weld 23, FIG. 9, to the steel substrate 21. The insert 35 is provided with 
a central welding rod hole 39 coaxial with and oversize with respect to 
the guide hole 13 to enable the welding as described above. Also, the 
insert 35 is formed so that when deformed as illustrated in FIG. 9, each 
leg of the V declines at a little less than approximately a 35.degree. 
angle toward the plane of the surface 12 and meets the other leg at a 
rounded juncture at 34. 
It will be appreciated that the weldable bricks described thus far may be 
readily used to line steel hoppers, chutes, or other conduits or surfaces 
that are accessible for welding through the guide holes 13. FIGS. 10 and 
11 illustrate a situation wherein the brick 10 may be provided with an 
undercut recess 24 opening at its inner face 12 as described above, but 
the guide hole 13 for the welding rod is eliminated. In lieu thereof, a 
hole 40 is burned or cut into the steel substrate 21 at the location where 
the weld is desired. The brick 10 with an interlocked insert 41 is then 
aligned with the hole 40. The weld between the insert 41 and substrate 21 
is then completed by conventional arc or MIG welding from the exterior of 
the substrate 21 through hole 40. The insert 41 may be identical with 
insert 35, except that the central hole 39 may be eliminated. 
FIG. 12 illustrates an application of the present invention lining a steel 
pipe for conveying abrasive materials. Large diameter pipes, for example 
two to four feet in diameter, may be welded to bricks 10 embodying the 
present invention from either the interior or exterior. As illustrated in 
FIG. 12, the opposite long sides of the bricks 10 are tapered to lie in 
radial planes extending longitudinally of the pipe 42. The bricks 10 may 
then be inserted into the pipe side by side circumferentially and end to 
end longitudinally and welded in place as described above and as 
illustrated by way of example in FIGS. 9, or 11. Smaller diameter pipes, 
or long pipes, will usually be welded from the exterior, as described in 
regard to FIG. 11, and illustrated in FIG. 13. 
Heretofore, pipes have been lined with abrasion resistant bricks installed 
entirely around the inner periphery of the pipe. The last brick 10b in 
each circle of bricks would be hammered into position to hold the other 
bricks in place. In the typical installation used for transmitting an 
abrasive slurry, usually less than half of the pipe is exposed to the 
slurry. Consequently, bricks around the upper portions of the pipe, 
required only to hold the remaining bricks in place, are a useless expense 
as far as resisting abrasion is concerned and add appreciably to the 
weight of the lined pipe. By virtue of the present invention, the key 
brick 10b is not necessary and bricks 10 are only welded in place as 
required within the pipe 42, as indicated by the solid line bricks 10, 
FIG. 12. Even if it is desirable to line the entire inner periphery of the 
pipe 42, as indicated by the bricks 10 and 10b shown in dashed line, the 
final brick 10b need not be precisely dimensioned and hammered into place 
because each brick is independently secured to the pipe 42 by welding. 
Where the face 12 of the brick 10 confronting the interior of the pipe 42 
is a plane surface defining a chord within the pipe 42, the insert 41 must 
be dimensioned so that its V-base in the deformed condition interlocked 
with the brick 10 will extend radially outward from the recess 24, FIG. 
13, to assure the desired welding space of approximately one sixteenth of 
an inch from the inner periphery of the pipe 42. In other respects the 
insert 1 may be identical to the inserts described in regard to FIG. 8 or 
FIG. 10. Of course, the chordal space between the brick 10 and pipe 42 can 
be eliminated if desired by forming the brick 10 with a cylindrical 
surface 12 to mate with the inner periphery of the pipe 42. Inasmuch as 
FIG. 13 is a section transverse to the longitudinal axis of pipe 42, the 
undercuts 25 for the recess 24 are not clearly shown. However, the recess 
24 in FIG. 13 may be identical with the recess 24 of FIGS. 8-11, wherein 
the longer dimension of the recess 24 in FIG. 13 preferably extends 
longitudinally of the pipe 42. 
FIG. 13 illustrates details of the pipe liner brick 10 provided with an 
undercut recess 24 and having an insert 41 secured therein. Holes 40 are 
cut through the pipe 42 at the locations where welding is required and 
each brick 10 is inserted into the pipe 42 with the center of its recess 
24 aligned coaxially with the hole 40. Thereafter, the weld is completed 
as described in regard to FIG. 11. Where it is feasible to weld from the 
interior of the pipe, a brick 10 having the guide hole 13, FIG. 15, is 
located within the pipe as desired and the welding is completed as 
described herein. 
Where pipes of smaller diameter are to be lined with ceramic bricks, the 
width of the brick between its tapered sides will be reduced so as to 
reduce the maximum distance between the interior of the pipe 42 and the 
adjacent surface 12 of the brick. In such instances, inasmuch as the width 
of the brick itself is reduced in its circumferential dimension, the width 
of the insert 41 between its longer edges, and also the width of the 
recess 24, will be correspondingly reduced. The length of the brick 10 
need not be reduced. It is apparent from the foregoing that the concept of 
the various weldable bricks described herein may be used to line the plane 
wall 21 as in FIG. 3, or the curved wall 42 as in FIG. 12. 
In some instances, the walls to be protected must also be capable of 
resisting corrosive action that would destroy ordinary sheet steel and 
many other weldable metals. FIGS. 14 and 15 illustrate modifications of 
dielectric non-metallic corrosion resistant walls for use with any of the 
weldable bricks described herein, whether such walls are curved or plane. 
The brick 10 of FIG. 14 may be shaped similarly to any of the bricks 10 
described above and may also be provided with a weldable insert 43 
similarly interlocked within recess 24. The insert may be similar in 
dimensions to any one of the inserts described herein, depending upon the 
shape of the recess therefore in the brick 10. For the purpose of 
illustration it is shaped like the insert 41. The pipe 44 in FIG. 14 is a 
dielectric material unsuitable for arc or MIG welding. Accordingly at a 
location aligned with the center of the insert 43, a hole 45 is cut 
through the wall of pipe 44 and a weldable corrosion resistant tubular 
grommet 46 of stainless steel for example, is secured within the hole 45, 
preferably so as to be frictionally retained in place. The tubular body of 
the grommet 46 extends radially through the wall of pipe 44 to the extent 
permitted by a coaxial annular flange 47 of the grommet 46 engaging 
adjacent exterior portions of the pipe 44 around the hole 45. The grommet 
46 is preferably formed from stainless steel capable of being welded by 
arc or MIG welding to the insert 43, and both the grommet 46 and insert 43 
are formed from weldable alloys capable of withstanding the corrosive 
abrasive mixture within the pipe 44. 
The grommet 46 is dimensioned such that after its insertion through the 
hole 45 in alignment with the center of the insert 43 as illustrated in 
FIG. 14, it will be spaced sufficiently close to the V-base of the insert 
43 to enable effective welding thereto. The grommet 46 is electrically 
grounded and welded to the adjacent portions of the insert 43 from the 
exterior of the pipe 44 by conventional arc or MIG welding to effect the 
weld 23 as described above. In this case, the material of the welding rod 
will also be resistant to the corrosive material within the pipe 44. A 
snug fit between the tubular body of the grommet 46 and the pipe 44, in 
cooperation with the weld 23 between the insert 43 and the inner end of 
the grommet 46 entirely around the latter, prevents leakage of the 
corrosive abrasive material from the pipe 44. Additionally, the chordal 
space between the brick 10 and the interior of the pipe 44 may be filled 
with a suitable corrosion resistant cement 48, as for example ordinary 
Portland cement that is forced axially along the pipe 44 from its ends. 
FIG. 15 illustrates a similar concept wherein the welding is feasible from 
within the pipe 44. In this situation, the brick 10 is provided with guide 
hole 13 and interlocked insert 43 having a hole 39 coaxial with the guide 
13. Except for being stamped from corrosion resistant weldable material 
and for the provision of hole 39, insert 43 of FIG. 15 may be the same as 
insert 43 of FIG. 14, or it may be similar to any of the other inserts 
described herein, such as insert 35. The inner end of the cylindrical 
grommet 46 in FIG. 15 may be closed by a unitary cap 49 to prevent leakage 
through the grommet 46. After the grommet 46 and guide hole 13 of the 
brick 10 are aligned, as in FIG. 15, the grommet 46 is electrically 
grounded and the MIG or arc welding is performed from within the pipe 44 
through guide hole 13 as described in regard to FIGS. 8 and 9, for 
example. Thereafter, the space between the brick 10 and pipe 44 may also 
be filled with a suitable cement as described in regard to FIG. 14. 
FIGS. 16 through 18 illustrate an adaptation of the present invention for 
use in lining a tubular elbow 50 comprising a number of pipe sections 51 
conventionally joined at mitered connections 52, as for example by 
welding, to effect in the present instance a 90.degree. elbow. FIG. 18 
illustrates an enlargement of one of the bricks 10 dimensioned for use in 
lining the separate sections 51. The opposite sides 53 and 54 of the brick 
10 are preferably tapered so as to lie in radial planes extending 
longitudinally of the associated section 51. The opposite ends 55 and 56 
are shaped so as to abut the adjacent end of the next endwise adjacent 
brick 10, which may be a brick in the next adjacent section 51. 
Preferably, each section 51 is lined with the bricks 10 before being 
joined to the next adjacent segment 51. 
Any of the brick modifications described herein may be used to line the 
separate sections 51, but bricks of the type illustrated in FIGS. 8 and 9 
are shown. In the present instance, the brick 10 of FIG. 18 is welded from 
the inside of the associated section 51, utilizing the guide hole 13, not 
shown, of FIGS. 8 and 9. After the bricks 10 are welded in place within 
the separate sections 51, the latter are then joined as for example by 
welding at 57 around their adjoining mitered edges 52, FIG. 17. 
FIGS. 19 through 22 illustrate modifications of the present invention 
wherein the weldable insert is deformed and interlocked within undercut 
portions of the insert receiving recess of a half inch thick brick 10 by 
being rotated 45.degree. to an interlocked position as described below. In 
FIG. 19, the insert 58 may comprise a sheet steel stamping of the same 
thickness and material as the inserts described above. The undercut 59 for 
the insert receiving recess 60 in the brick 10 undercuts the four sides 61 
of the recess adjacent to the recess ceiling 62. The latter extends 
transversely of the guide hole 13, where used, FIGS. 19-21, and parallel 
to the surface 12, FIG. 22, and the four sides 61 extend essentially at 
right angles to the surface 12 to define approximately an inch square or 
slightly less recess receiving opening (in a four inch by six inch brick 
10) dimensioned to receive the weldable insert 58 freely therein. 
The insert 58 has a plane base 63 provided with a hexagonal hole 64 coaxial 
with and slightly larger in diameter than guide hole 13. From the base 63, 
each pair of opposite sides 65 of the insert 58 diverge from each other 
toward the ceiling 62 to their outermost edges 66. The latter define the 
essentially square plan view of the insert 58, but the corner portions 67 
of the otherwise square edges 66 bend downward slightly to an extent 
preferably not greater than the thickness of the sheet steel material from 
which the retainer 58 is stamped. Approximately the central half of each 
of the edges 66 lies in a common plane, such that approximately only a 
quarter of an inch of each edge 66 bends downwardly at the corner portions 
67. 
When the insert 58 is inserted into the recess 60, the edges 66 lie flush 
with the ceiling 62. The depth of the undercut 59 in the axial direction 
of the guide hole 13, FIGS. 21 and 22, is slightly greater than the 
thickness of the edges 66. Thus the undercuts are dimensioned to receive 
the edges 66 and to effect an interference fit with the depressed corners 
67 when the insert 58 is rotated 45.degree. in either direction from the 
initial inserted position. Rotation of the insert 58 may be accomplished 
by means of a tool fitting closely within the hexagonal opening 64, which 
preferably is reinforced by upwardly punched portions 68 of the base 63 
that define the hole 64. 
When the insert 58 is rotated from its initial installed position adjacent 
to the ceiling 62, FIG. 21, to the deformed position illustrated in FIG. 
22, or FIG. 20, dotted lines, the edges 66 initially clear the adjacent 
lower surfaces of the undercuts 59 opposite the ceiling 62. Upon continued 
rotation, the declined portions 67 engage the aforesaid lower surfaces of 
the undercuts 59 and are deformed by cam action toward the ceiling 62. The 
insert 58 is thus frictionally and mechanically interlocked by the 
deformation within the recess 60 when the rotation continues 45.degree. 
from the FIG. 21 position to the FIG. 22 position. The lateral extent of 
the undercuts 59 is determined so as to receive the corners 67 when these 
are deformed upwardly toward the plane of the edges 66, dotted lines, FIG. 
20. After the insert 58 is interlocked within the recess 60, the brick 10 
of FIGS. 19-21 is used as a transportable self-contained assembly for 
welding to a wall to be protected, as described above. 
FIGS. 21 and 22 illustrate respectively the concept of the weldable brick 
10 and interlocked insert 58 within a recess 60 wherein the brick 10 is 
welded by use of guide hole 13 from the interior of a chute or conduit, as 
described in regard to FIG. 8 and 9, and the concept wherein the guide 
hole 13 is not used and the brick 10 is welded to the exterior of a wall 
21 through hole 40 therein as described in regard to FIGS. 10 and 11. The 
bricks 10 of FIGS. 19-22, as is also true of other bricks 10 described 
herein, may also be welded to grommets or buttons 46 secured to dielectric 
walls as illustrated in FIGS. 14 and 15. 
FIGS. 23-26 illustrate another concept of the present invention that 
facilitates molding of the brick 10 having a recess 70 for receiving a 
welding insert 71 and enables use of a comparatively simple multiple part 
mold, FIGS. 33, 34. The brick 10 may or may not be provided with a guide 
hole 13, depending upon the application as described above. Similarly to 
the above described recesses, the recess 70 has a rectangular inner insert 
receiving opening at the brick surface 12, a ceiling 72 parallel to the 
surface 12, and orthogonal lateral walls 73 and end walls 74 that are also 
essentially normal to the ceiling 72. 
The welding insert 71 may be stamped from sheet steel as described above to 
provide an approximately 110.degree. V-shaped insert, FIG. 24, having a 
pair of legs 75 offset from each other at opposite sides of the 
longitudinal mid-plane of the insert 71, FIGS. 23 and 26, and projecting 
endwise in opposite directions. The recess 70 has a pair of undercuts 76 
at its opposite ends and offset from each other to receive the ends of the 
legs 75. 
Similarly to the structure illustrated in FIG. 9, for example, the insert 
71 is readily insertable through the inner recess opening, with the legs 
75 diverging from the centrally located V-apex 77 toward the ceiling 72, 
which extends endwise into the offset undercuts 76. Flattening force 
applied against the mid-region 77 toward the ceiling 72 forces the ends of 
the legs 75 to slide endwise along the ceiling 72 into the mating 
undercuts 76 to interlock the insert 71 and brick 10. Each leg 75 is 
offset laterally from the other and extends endwise approximately 20% of 
the overall length of the insert 71 from a transverse edge 78 of the 
insert body. At the region of each transverse edge 78 of the deformed 
insert 71, the ceiling at the same lateral half of the recess 70 slopes 
endwise toward the inner recess opening and terminates at the surface 12 
to provide a ramp 79. Each ramp 79 extends transversely of the recess 70 
from the adjacent lateral wall 73 to the longitudinal mid-plane of the 
recess 70 and thus defines a wall 80 that extends along the latter 
mid-plane for the extent of the ramp 79. When used with a brick 10 having 
a guide hole 13, a hole 81 is provided centrally within the insert 71 to 
enable welding as described above. 
By virtue of the structure described and illustrated in FIGS. 23-26, a 
multiple part mold may be used to form the brick 10. Numerous multiple 
part molds are well known to the art and the molding operating itself may 
be conventional. These are accordingly not described in detail herein, 
except to the extent that a pair of identical recess forming mold parts or 
inserts 84, FIGS. 33, 34, are located within the mold cavity to form the 
recess 70. Each recess forming part 84 is suitably supported within the 
mold cavity to form one lateral half of the entire recess 70 and may 
comprise a plane ceiling forming surface 87 for forming one lateral half 
of the ceiling 72, a ramp forming curved portion 88 at one end of the 
surface 87 for forming one of the ramps 79, an undercut forming projection 
89 at the opposite end of the surface 87 for forming the associated 
undercut 76, an endwall forming portion 90 adjacent to the portion 89 for 
forming the associated end wall 74, a lateral wall forming side 91 for 
forming the associated lateral wall 73, and an opposite side 92 for 
forming the mid-plane wall 80. Suitable means such as a depending stem 93 
may be provided to facilitate removal of the associated part 84 from the 
recess 70 upon completion of the molding operation. During the molding 
operation the dry powdered material for forming the brick 10 is compacted 
within the mold under a pressure of approximately 3500 psi. When the mold 
is opened to expose the green newly compressed brick and to release the 
molding pressure, the brick will initially expand slightly. Such expansion 
facilitates removal of the recess forming inserts 84 which may then be 
gripped, as for example by the stems 93, and withdrawn from the recess 70 
in directions along the ramps 79 and away from the ceiling 72, as 
illustrated in FIG. 33. 
FIG. 31 illustrates a concept of the present invention wherein welding 
inserts, such as the inserts 71, may be employed to interlock with a 
hardenable plastic poured in a fluid condition into the recesses of a 
number of bricks 10. The bricks 10, interlocked with any one of the 
inserts described herein, such as the inserts 71 by way of example, are 
placed side by side, with the recesses 70 up, on the surface on a 
supporting form or mold 94 having a raised border 95. A hardenable 
thermoplastic or thermosetting plastic 96 in a low viscosity fluid 
condition is poured over the layer of bricks 10 to a desired depth of say 
one-quarter inch to an inch or more. The low viscosity plastic 96 readily 
flows into the recesses 70 and through the holes 81 and between the edges 
of the inserts 71 and recess walls to completely fill each recess 70 and 
interlock with the inserts 71 after hardening. 
The flat form 94 is suitable for use with a hardenable thermoplastic and 
may be provided with a riser 97 confining the outermost edges of the 
bricks 10. Also if desired the form 94 may be provided with a peripheral 
step 98 between the riser 97 and border 95 and flush with the upper 
surface 12 of the adjacent bricks 10, so that the overlying plastic 96 
when hardened will form an extension 96a that can be drilled and bolted to 
a structure to be protected after the hardened plastic 96 and interlocked 
bricks are removed from the form 94. In lieu of the extension 96a, the 
upper surface of the hardened plastic 96 may be cemented or otherwise 
secured to the structure to be protected by the abrasive and impact 
resistant bricks 10. 
For use with thermosetting plastics or to form interlocked assemblies of 
plastic 96 and bricks 10 of curved or other than flat contours, a second 
mold part may be used in cooperation with the support 94 to confine the 
bricks 10 and plastic 96 therebetween in accordance with conventional 
molding practice to form any desired shape. 
Also where it is desired to emphasize the interlocking between the plastic 
96 and metal insets 71, the latter may be modified in various ways, as 
illustrated in FIGS. 27, 28, and FIGS. 29, 30 by way of example. In FIGS. 
27, 28, the hole 81 is eliminated and a pair of prongs 99 are lanced from 
the body of the insert 71 to enhance the above mentioned interlocking. In 
FIGS. 29, 30, an unbroken loop 100 is lanced from the body of the insert 
71 to effect an even stronger interlock. Also within the concept of the 
present invention, the undercut portion of the recesses 70 may be 
increased to enable elimination of the metal insert. In that situation, 
the interlock between the block 10 and plate 96 may be effected solely by 
reason of the undercut recess 70. 
FIG. 32 illustrates a modification of the invention where the bricks 10 are 
bonded directly to a structural member to be protected, which may be a 
steel plate 101 or other rigid substrate. The surface 102 of the plate 101 
to be protected is preferably roughened, as for example by shot blasting, 
to enhance adherence to an adhesive. The plate 101 replaces the form 94, 
although a border 103 may be clamped to the roughened surface 102 to limit 
lateral flow of the adhesive. Thereafter the surface 102 is buttered with 
a suitable fluid adhesive 104, which may comprise an epoxy or other resin, 
and a layer of bricks 10 is pressed, with the recesses 70 down, on the 
adhesive 104 before it hardens, thereby to force the adhesive upwardly 
into the recesses 70 and around the insert 71 to mechanically interlock 
therewith upon hardening. Although the smooth hard surface of the bricks 
10 confronting the steel surface 102 is not amenable to secure bonding 
merely by means of an adhesive, the interlock between the adhesive 104 
within the recesses 70 and around the inserts 71 effects the desired 
strong bond for securing the abrasion and shock resistant bricks 10 to the 
substrate 101. Also as described in regard to FIG. 31, the undercut 
portions of the recesses 70 may be enlarged to effect the desired 
interlock with the adhesive 104 without recourse to metal inserts.