THROWDERUNG IN AND IN THE MANUFACTURE OF SAGGARS
Year: 1857

page_text: LETTERS PATENT to Joseph Skertchly, of Culford Road, De
Skertchly, of Culford Road, De Beauvoir
.Square, in the County of Middlesex, Engineer, for the Invention of
THROWDERUNG IN AND IN THE MANUFACTURE OF SAGGARS."
Sealed the 4th August 1857, and dated the 7th February 1857.
PROVISIONAL SPECIFICATION left by the said Joseph Skertchly at the
Office of the Commissioners of Patents, with his Petition, on the 7th*
February 1857.
I, JOSEPH SKERTCHLY, of 77, Culford Road, Kingsland, in the County of
Middlesex, Engineer, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN AND IN THE MANUFACTURE OF SAGGERS" to be as follows:-
Firstly, I employ in the composition of the material for the manufacture
of saggers such an amount of fire clay as enables them to be fired repeatedly
to a high degree of heat, and I fire them in the first instance to a higher
degree of heat than they will ever again be subjected to when containing
arthenware.
· Secondly, I use manganese in addition to the other usual ingredients__
when I deem it important to toughen the material and to reduce its amount
of expansion.
Thirdly, I form the sides and bottoms of saggers by machinery instead of
by manual labour, as has been usual heretofore. 'I force out of a cylinder,
chamber, or other vessel straight flat webs of clay to form the sides of the
saggers. The bottoms I form from curved webs made (by similar machinery)'

page_text: of the same material, and which may be made in the first instance in the
shape of cylinders and then cut open longitudinally. I force the convex
side of the web so as to form the upper or inner surface of the bottom, for
the purpose of securing additional strength, and preventing their sinking
under the action of the fire. I then put the sides and bottoms together in
the usual manner. Sometimes I find it convenient to form the sides of
گلا
saggers out of tubes. This method prevents the necessity of forming a side
joint when the tube is of a proper diameter, but when the tube is too large
or too small it must be cut open, reduced to the proper size, and then have
its edges united; or it must be cut open and have a second piece laid in, as
the case may be.
Fourthly, when the sides are made from a flat web, I sometimes thicken
the upper edge of the sagger, and bevil or round it off, in order to give
increased strength to this part, which is liable. to be chipped or broken while.
setting in and withdrawing from the kiln.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Joseph Skertchly in the Great Seal Patent Office on the
7th August 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOSEPH
SEERTCHLY; of Culford Road, De Beauvoir, in the County of Middlesex,
Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventh day of February, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her.
reign, did, for Herself, Her heirs and successors, give and grant unto. me,
the said Joseph Skertchly, Her special licence that I, the said Joseph Sketchly,
my-executors, administrators, and assigns, or such others as I, the said Joseph
Skertchly, my executors, administrators, and assigns, should at any time agree
with, and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use, exercise,
and vend, within the. United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN AND,
IN THE MANUFACTURE OF SAGGARS," upon the condition (amongst others) that I,
the said Joseph Skertchly, my executors or administrators, by an instrument
in writing under my, or their, or one of their hands and seals, should par-,
ticularly describe and ascertain the nature of the said Invention, and in what.
"

page_text: manner the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next, and immediately
after the date of the said Letters Patent.
شرح
NOW KNOW YE, that I, the said Joseph Skertchly, do hereby declare
the nature of, my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Drawings hereunto annexed, that is
to say:
It has heretofore been usual for earthenware manufacturers to fire their
saggars with. the ware they produce, and in order to keep up the supply one
or more have been placed on each bung every time the kiln was fired. From
this circumstance it is evident that the saggars can receive no higher heat in
their manufacture than the earthenware which has subsequently to be fired.in
them. It is desirable that saggars should receive in their manufacture a much
higher heat than they are ever subjected to afterwards in their general use,
for it is the nature of fired plastic materials to undergo but trifling, change in
their condition at any lower degree of heat than that which they have already
sustained. The marl of which saggars have been for the most part composed
is generally subjected for a considerable time to the action of the air, which is
found by practice to improve its condition. After being tempered to a
proper
consistency it is beaten out by manual labour to the required dimensions,
and moulded into suitable forms upon drums, which determine the sizes and
shapes. From the mode of firing herein-before described the 'manufacturers
have to select marls of such strength and quality as are found to produce
the best and most durable saggars when fired to the particular degree of
heat which is necessary for the production of the ware; for if materials
were used under these conditions. requiring more heat than the ware the
saggars would be insufficiently fired, and, on the contrary, if the saggars were
fired to the heat, necessary to their perfection the ware would be overfired
and probably spoiled.
1.
My improvements in and in the manufacture of. saggars consist, firstly, in
employing in their construction. such an amount of fire clay as necessitates,
in order to complete the operation of firing, the employment of a higher
degree of heat than they will ever again be subjected to when containing
earthenware. I. find in practice that from thirty-five to seventy-five per cent.
of..fire clay is desirable to be added to the ordinary marl, and that the pro-
portion of fire clay should be the greatest in those cases where the character
of the ware to be burnt in thèm requires the greatest amount of firing. For
saggars .that .are to be employed in manufacturing yellow ware I find a

page_text: 2
mixture of forty per cent. of fire-clay with sixty per cent. of marl to be
sufficient; for queen's ware. and similar bodies equal quantities of...marl
and fire clay may be employed; while for china I prefer to use an excess of
:fire clay, 'and find seventy per cent. of that material to thirty per cent. of
-marl to produce a good result.. Saggars composed of these or similar com-
pounds requiring a higher degree of heat to perfect them than is required
by the ware for which they are afterwards to be used I fire by themselves
in kilns apart from the ware, and am thus enabled to carry them to any
degree of heat that is found in practice to produce the best result.
..
Secondly, when the marl and fire clay, or either of them, are in their 1
peculiar character "short" or "weak," I toughen or strengthen the body,
and reduce the amount of expansion under the action of fire by adding
: three to five per cent. of manganese to the various compounds herein-before
.described...
Thirdly, my Invention consists in forming certain parts of the saggars by i
machinery, which have heretofore been produced by hand labor. I. force
out of a cylinder chamber, or other suitable vessel containing the material to
be operated upon, straight flat webs to form the sides of the
saggars. The
-bottoms of the saggars I form of webs curvilinear in their cross sections,
made in like manner by similar machinery and of the same material. These-
curved webs for the bottoms of the saggars I sometimes make in the form of
*tubes or cylinders and afterwards cut them open longitudinally, taking care
that the portion employed to form a single bottom does not greatly exceed in
cross section half the circumference of the entire tube or cylinder.
In order that this part of my Invention may be clearly understood I will g
proceed to explain the Drawings hereunto annexed, similar letters referring to
corresponding parts in the different views.
Figure 1 is a side elevation, and Figure 2. a section, of an apparatus I
employ for forming the sides and bottoms of the saggers. A is the cylinder
or vessel into which the material B is placed; C is the piston, operated s
.upon through the piston rod D by any prime mover; E is the die plate,
having an opening F through which the. material is. forced. This opening
determines the size and shape in cross section of the web or tube to be
; expressed from the cylinder. Figure 8 is a plan of one of these die plates.
The operation of the apparatus is as follows:-The piston C being entirely.
withdrawn from the cylinder A, the material is placed in as shéwn at B,
Figure, 2.. Motion being then communicated through the piston rod D, the
-piston Gin its passage down the cylinder. drives.out the material B through
the opening. F of. the die plate E, which I cut, having the cross section either

page_text: These webs I cut into
Figures 4, 5, and 6, are
of flat, curvilinear, or circular form, according as it is desirable to produce webs
or. tubes for the sides or bottoms of, the saggars.
convenient lengths for the different sized saggars.
respectively cross sections of the flat web, curved web, and tube. Figure 10
represents a side elevation of the tube shown in Figure 6; and Figure 11:a
cross section of the same after the bottom has been added, as it appears in the
finished saggar.
Another mode of forming the sides and bottoms of saggars, and which is
merely a modification of the plan herein-before described, consists in forcing
the clay by means of rollers into a chamber or recess, as shewn in Figure 7
in front elevation, and Figure 8 in cross section. The material in this case
is supplied to the rollers H, H, at e, and on motion being given to them by
..turning the handle I, it is forced. by their action into the chamber or recess J
until it is entirely filled. The material being still supplied to rollers, after
the chamber J is full, is forced onward towards and through the openings L of
the die plate K, (which is screwed on to the front of the recess J.) These
openings L correspond in shape with the cross sections of the webs and tubes,
as herein-before described. Figure .9.is a plan of one of these die plates for
forming curved webs. L is the opening referred to.
Having thus formed the sides and bottoms separately, I proceed to com-
plete the saggar on a drum in the usual manner, taking care to keep the
convex side of the web or tube uppermost in the bottom of the saggar. By
this means. I obtain additional strength in the bottom of the sâggar, and
prevent its sinking under the action of the fire at any lower temperature than
that to which it has in the process of its own manufacture been subjected.
Sometimes I find it convenient to form the sides of saggars from tubes.
In this case I place the tube itself around the drum when it is of the exact
size to fit, and affix the bottoms as herein-before described. Should the
drum exceed the size of the tube, I then open the tube longitudinally and
insert a strip in the opening thus formed, which I cut away from another
tube in the same direction. For those saggars where the drum is less than
the tube, I cut away longitudinally from the latter sufficient to reduce it
to the proper size and then proceed to finish the saggar in the usual
manner.
Fourthly, I sometimes thicken the upper outer edge of the saggar when
the side is made from the flat web and bevil or round it off. By this means I
strengthen the saggar in a part where it is liable to receive injury in setting
and drawing from the kiln.
Having described the nature of my Invention; and the manner in which

page_text: the same is to be performed, I should observe that I do not confine myself to
the precise proportions specified in the above-named mixtures of materials
for saggars, nor to the precise detail of manufacture. as herein set forth, as
they may be varied without departing from my Invention; but what I claim
as new, and desire to secure by Letters Patent, is,
First, the employment of such, an amount of fire clay in the structure of
the saggars as shall require in their original manufacture a higher heat than
is required for the ware which has afterwards to be burned in them.
Second, the employment of manganese. to toughen the body of saggars
and reduce their expansion in all firings subsequent to their original manu-
:facture.
Third, the making the sides and bottoms of saggars from webs, tubes,
For portions of tubes expressed from cylinders or other vessels by. mechanical
*means.
Fourth, the thickening of the outer upper edge of the saggars, for the
purpose herein described.
In witness whereof, I, the said Joseph Skertehly, have hereunto set my
hand and seal, this Seventh day of August, in the year of our Lord
One thousand eight hundred and fifty-seven.
JOSEPH SKERTCHLY. (L.S.)