Note: Descriptions are shown in the official language in which they were submitted.
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Background of the Invention
tl) Field of the Invention:
This invention re1ates to a material for treating coke ovens and
the doors thereon to provide for the sealing of the doors with respect
to the jambs during the coking operation.
(2) Description of the Prior Art:
Coke ovens are provided at their opposite ends with self-sealing
doors that depend on a metal to metal contact between the door and the
continuous machined surface cast iron jamb.
In a typical example the sealing edge of the door is carried by
a flexible frame and the door assembly includes a powerful spring between
the door and the locking bar to force the sealing edge against the metal
door jamb to prevent the escape of volatile products from the coke oven.
Such door and jamb assemblies on the coke side and pusher side of the
coke oven commonly fail to maintain a sealing metal to metal relation
and tar and other by-products produced during the coking operation escape
and build up between the door and jambs and must be manually removed each
time the doors are removed and repositioned when the coke is pushed from
the oven. The tar andby-products build up deposits which are difficult
to remove and the removal is time consuming so that frequently the
doors are repositioned and the desirable se,aling relation to effect an
efficient coking operation is adversely affected.
The present invention relates to a material for forming a penetrating
and lubricating adhesive coating on the sealing edges of the doors and
jambs that is not affected by the heat of the coking operation and to
26 which tar and other by-products will not adhere with the result that
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the sealing edges of the doors and the jambs which are engaged thereby
remain clean and free of tar and other by-product build up and can
effectively seal the coke oven.
The prior art comprises my U.S. Patents Nos. 4,187,334 and 4,187,335,
issued February 5, 1980.
Summary of the Invention
A material for treating coke oven doors and jambs to prevent the
build up of tar and other coke oven by-products thereon, contains essentially
submicron sized particles of graphite in an improved liquid carrier wherein
the extremely fine size of the submicron sized particles of graphite lowers
the surface tension of the liquid carrier and enables the submicron sized
graphite particles to penetrate the metal surfaces of the coke oven doors
and jambs and also build up a smooth adhering surface coating. The
liquid carrier comprises water, an aqueous sodium silicate solution,
hydrochloric acid, and a water soluble resin such as a carboxylated
polymer, for example, carboxy polymethalene, or the like. The
submicron sized graphite particules because of .heir critical size
contribute to the penetrating, lubricating and adhesive coating
ability of the material when applied to the coke oven doors anà
jambs as by spraying the same thereon.
Description of the Preferred Embodiment
The material of this invention that is particularly suitable for
supplying a penetrating and lubricating adhesive _oating to coke oven
; doors and jambs comprises substantially between about 5o and ~5O by
weight submicron si-ed particles of graphite, between about 34~ to 75~
- by weight of a solu~ion of water and sodium silicate (Na2Si3 q) wherein
the sodium silicate is present at about 40~ of the solution by weight,
; 28 between about 2~ and 10~ concentrated hydrochloric acid of a 90~ purity by weight,
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between about 33% to 75% of a solution of water and carboxy polymethylene
polymer resin wherein the resin is present in amounts between 1~ and 10%
of the solution by weight.
The critical particle size of the submicron sized graphite particles
being substantially amicron; less than 4m~4or 10-7CM as determined by
electron microscopy. The submicron sized graphite particles are made by
ball milling the finest mesh colloidal graphite particles commercially
available for a time sufficient to obtain the desired submicron graphite
particle size which eliminates the platelets. The carboxy polymethylene
polymer resin powder has a specific gravity of 1.41 and a bulk density
of 13 lbs. per cubic foot. It is available as "CARBOPOL" from B.F. Goodrich
Chemical Co. and low concentrations mixed with water as herein disclosed
produce a thin gel-like liquid with penetrating and adhesive qualities.
The liquid carrier as set forth hereinbefore comprises an effective
wetting agent which contributes to the ability of the submicron sized
particles of graphite to form a penetrating lubricating and adhesive
coating in and on the coke oven doors and jambs.
Those skilled in the art will also observe that the percentage of the
submicron s.zed particles of graphite and the materials in the liquid
carrier may be widely varied depending upon the number of applications of
the material to the metal parts being treated. For example small percentages
of the submicron sized particles of graphite in the liquid carrier perform
effectively when a number of applications of the material are applied
and when only one or a few applications of the material are applied to
the metal surfaces, a higher percentage of the submicron sized particles
of graphite are essential. In either case the material penetrates the
metal surfaces being treated and builds up an extremely smooth, slick
28 surface coating of excellent adherence to which the tar and by-products
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from the coke oven will not aclhere or if some adherence occurs the aclhering
material may be easily removed by air or water or other fluid jets.
In using the material disclosed herein the process involves mixing
the materials to form a liquid suspension of the submicron sizecl particles
of graphite and the other materials and then spraying thc same by any
suitable spraying equipment on cleaned metal surfaces of the coke oven
doors and jambs to be treated. One or more coatings are applied as
necessary to build up the smooth unbroken surface of the material in and
on the metal parts being treated and the material may be applied to the
metal surfaces while they are either hot or cold.
The ability of the material to be applied to the hot metal surfaces
is particularly advantageous in a coke oven operation as the doors are
removed from the ovens to permit a pusher to move the coke from the ovens
while the ovens themselves are maintained at or near coking temperatures.
Those skilled in the art will observe that the heretofore necessary
manual cleaning of the doors and door jambs frequently required motorized
buggies and similar mechanical equipment and the tiMe of such cleaning
is eliminated through the use of the material hereinbefore disclosed.
It will also be observed that the production ol~ metallurgical coke
is improved and stabilized by providing for the effective sealing of
the coke oven doors made possible with the material herein disclosed.
It has been determined that other applications and uses of the
material disclosed herein are possible and such may include the treating
of forging dies in the hot forging oF metals and the treatment of various
metal handling and processing equipment wherein the surface condition of
the metal treating equipment is desirably maintained in a smooth condition
resisting adhesion or contaminates thereto.
28 Additionally ingot molds are advantageously treated with the material
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of the invention as such treatment expedites the stripping of ingots
from the molds. The following specific examples oF the material have
been found satisfactory for the treatment of coke ovcn doors and jambs
and like metal surfaces.
A. Substantially 8~ by weight submicron sized particles of high
pwrity synthetic graphite, substantially 7% by weight concentrated hydro-
chloric acid of substantially 90~ purity, substantially 18% by weight
water (H20), substantially 34% by weight aqueous sodium silicate solution
wherein the Na2Si307 is present at about 40% by weight of the solution
and substantially 33% by weight of a solution of water and a water
soluable carboxy polymethylene polymer resin as a powder wherein the resin
is present at substantially 8~ by weight of the solution.
B. Substantially 8% by weight submicron sized particles of high
purity synthetic grahite, substantially 7% by weight concentrated hydro-
chloric acid of substantially 90% purity, substantially 18% by weight
water (H20~, substantially 67% by weight aqueous sodium silicate solution
wherein the Na2Si307 is present at about 40% by weight of the solution.
C. Substantially 8% by weight submicron sized particles of high
purity synthetic graphite, substantially 7% by weight concentrated hydro-
chloric acid of substantially 90% purity, substantially 18% by weightwater (HæO), substantially 67~ by weight aqueous solution of carboxy
polymethylene polymer resin as a powder wherein the resin is present
at substantially 8% by weight of the aqueous so1ution.
An alternate liquid carrier has been found to produce a suitable
suspension of the submicron sized particles of graphite and substitutes
xanthan gum for the resin, the gum is a natural high molecular weight
linear polysaccharide, functioning as a hydrophilic colloid to maintain
28 the submicron sized particles of graphite in suspension and contributes
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to the penetrating lubricating adhesvie coating as described hereinbefore.
A specific example of such an alternate material follows:
D. Substantially 8% by weight subm;cron sized particles of high
purity synthetic graphite, substantially 7'~ by weight concentrated hydro-
chloric acid of substantially 90% purity, substantially 18~ by weight
water (HzO), substantially 67% by weight aqueous solution of xanthan
gum as a powder wherein the gum is present at substantially 8% by weight
of the aqueous solution.
Variations in the amounts of xanthan gum may be used as from 1% to
19~ of the aqueous solution.
; The treatment of coke oven doors and jambs hereinbefore referred to
with the material disclosed herein obtains excellent results by reason
of the very fine submicron sized graphite particles of the material in
the liquid carrier.
The material of the invention can be used in the treatment of
ingot molds and obtains unusual results in freeing an ingot from the
mold for the reason that molten steel in an ingot mold takes carbon
from the metal of the ingot mold thereby adversely affecting the irterior
of the mold by removing portions thereof. It is also known that when
20 this occurs, the stripping of the cooled ingot from the mold becomes more
difficult because of the interlock obtained between the solidifying ingot
metal and the irregular surface of the mold. By heating an ingot mold
the grain structure enlarges and the porosity of the metal increases and
the material is preferably applied ~o the mold when it is heated as by
spraying.
Under such conditions the submicron sized particles of graphite
aided by the materials in the liquid carrier penetrates the metal surfaces
28 of the ingot mold which have been previously cleaned and build up a
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smooth 1ubr;cating and adhereing coating which becomes largely graphite
and is able to supply the carbon that molten steel absorbs, usually
from the ingot mold.
Thus the treatiny material is sacrificed to some degree and
the inner surface of the ingot mold retained in its desirable smooth
condition. Stripping ingots from such a smooth inner surface of
the mold is thus considerably expedited and the molds last consider-
ably longer as the carbon from the metal of the molds is not
sacrificed as has heretofore been common in the art. The material
of the present invention therefore has been advantageously used in
treating ingot molds as well as its primary function of treating
- coke oven doors and jambs.
Although the embodiments of the present invention have been
limited as described hereinbefore, it will be apparent to those
skilled in the art that various changes and modifications may be
16 made therein without departing from the spirit of the invention.
