IMPROVEMENTS IN THE MANU- FACTURE OF PIPES, WHEN APPLYING SLATE FOR SUCH PURPOSE
Year: 1854

page_text: LETTERS PATENT to Bewicke Blackburn, of Clapham Common, in the
County of Surrey, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE OF PIPES, WHEN APPLYING SLATE FOR SUCH PURPOSE."
Sealed the 81st October 1854, and dated the 8th June 1854.
PROVISIONAL SPECIFICATION left by the said Bewicke Blackburn at
the Office of the Commissioners of Patents, with his Petition, on the
8th June 1854.
I, BEWICKE BLACKBURN, of Clapham Common, in the County of Surrey, do
hereby declare the nature of the Invention for "IMPROVEMENTS IN THE MANU-
FACTURE OF PIPES, WHEN APPLYING SLATE FOR SUCH PURPOSE," to be as follows:-
This Invention consists in applying small slates, laid in a cylindrical form,
overlapping each other and cemented together, to the construction of conduit
pipes. The slates preferred are those commonly used for field drains, about
twelve inches long, from three to five inches wide, and about one quarter inch
thick; these dimensions may be varied. The cement preferred is the asphalte
commonly used for cementing brickwork and coating arches.
The process of laying and cementing the slate found most convenient is as
follows: A cylinder of thin sheet iron, of an external diameter equal to the
internal diameter of the intended pipe, is mounted on a horizontal axle, and
caused to revolve at about one hundred revolutions an hour. Whilst revolving,

page_text: the slates one by one are laid and bound with a wire on to the cylinder,
overlapping and breaking joint with each other, as on a roof; an outer casing
of thin sheet iron is then bound round them, and the whole heated in an oven
to about three hundred degrees Fahrenheit, and being set up on one end on a
bed of dry sand, the asphalte heated to fluidity is poured into the interstices of
the slates. When cold, the external and internal casings of sheet iron, which
had been previously coated with lime or other matter to prevent adhesion, are
stripped off. When sockets are required, a heated cast-iron collar, of a T
section, is fitted on to one end of the pipes, and of an ✓ section on to the
other end. In laying the pipes, the spigot end of each is slightly softened by
a salamander, and forced into the socket of the next pipe.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Bewicke Blackburn in the Great Seal Patent Office on the
5th December 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, BEWIOKE
BLACKBURN, of Clapham Common, in the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of June, in the year of our Lord One
thousand eight hundred and fifty-four, in the seventeenth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the said
Bewicke Blackburn, Her special licence that I, the said Bewicke Blackburn,
my executors, administrators, and assigns, or such others as I, the said Bowicke
Blackburn, 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 Chanuel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN THE MANUFACTURE
OP PIPES, WHEN APPLYING SLATE FOR SUCH PURPOSE," upon the condition (amongst
others) that I, the said Bewicke Blackburn, by an instrument in writing under
my hand and seal, should particularly describe and ascertain the nature of the
said Invention, and in what 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.
NOW KNOW YE, that I, the said Bewicke Blackburn, do hereby declare the
nature of the 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 thereof (that is to say) :-

page_text: This Invention consists in forming pipes of various sizes, generally from
about nine inches to about three feet in diameter, and up to eight feet or more
in length, by binding and cementing small slates together in a cylindrical form,
the pieces of slates being so disposed as to overlap and break joint with each
other, and thus form a kind of wicker or woven work, consisting of slates and
iron cemented and concreted with asphalte or other suitable cement.
The slates preferred for this purpose are about one-quarter inch thick, and
about twelve inches to about eighteen inches long, and from about three inches
to about five inches wide; the narrow slates being used for pipes of small
diameter, and the wider slates for pipes of large diameter. For binding the
slates it is preferred to use hoop iron about one-twentieth of an inch thick,
and from about one-half an inch to an inch wide. The cement preferred is the
asphalte formed by mixture of coal pitch with pounded chalk or stone or
other powder, the following proportions being found most suitable :-Two
hundredweight of coal pitch to one hundredweight of chalk, ground to an
impalpable powder, and three hundredweight of limestone or shells or slate,
ground fine enough to pass through a sieve, the openings in which are about
one thirty-second of an inch square. The method of making these pipes is as
follows:-A cylindrical mould, the same diameter and length as the intended
pipe, is formed of one or more sheets of iron, about one-twentieth of an inch
thick, the longitudinal edges overlapping each other about three inches, to
prevent escape of asphalte. This cylinder is fixed to an axle and made to
revolve at a speed at its circumferenco of about six feet a minute, and as it
revolves, the slates one by one are laid and bound on it by one or more lines of
hoop iron or iron wire, which are drawn off reels by the revolution of the
cylindrical mould, friction being applied to the reels to keep the binding iron
sufficiently tight, see Figure 1. A layer of slates overlapping and breaking
joint with each other is thus laid and bound along the whole length of the
cylindrical mould. It is preferred that one line of binding iron should pass
over the upper ends of the slates, and two lines at their lower ends, these
latter passing alternately the ono over the other under each slate, as the threads
of a warp pass the woof in weaving, these two lines being raised and lowered
alternately in the same way as the threads of a warp usually are. When the
pipes are to be furnished with spigott and faucett joints, a cast-iron cap, as
shewn by C, C, Figure 2, is to be driven on to the last row of slates; a jacket
formed of one or more sheets of iron, about one-twentieth of an inch thick,
is next to be bound by straps, or otherwise, closely round the outside of the
layer of slates, the longitudinal edges overlapping about three inches, so as to
prevent the escape of any asphalte. The whole is then to be put into a

page_text: chamber, heated by steam or otherwise, and gradually raised to a temperaturo
of about two hundred and thirty degrees Fahrenheit. It is then to be set
upright, standing on the end to which the cast-iron cap was fixed, resting on
a bed of fine chalk (so as to prevent any escape of asphalte from the bottom),
and whilst the cylinders and slates are at the temperature of about two
hundred and thirty degrees, the asphalte, heated to its greatest degree of
fluidity, is poured in at the top, between the inner and outer cylinders of sheet
iron, so that it may flow down amongst the slates and fill up the interstices,
and make a solid concrete of the whole. When the asphalte is cold, the
inner and outer cylinders of sheet iron are to be peeled off, and a ring of cast
iron, in the form of a faucett, as shewn at.F, F, Figure 2, heated to about one
hundred and fifty degrees, and coated with the asphalte, is forced tightly down
on to the upper end of the pipe, and the pipe is then complete. The thickness of
the pipes is to be in proportion to their diameter, and to the internal pressure
they are to stand. A pipe of nine inches diameter, to stand the pressure of
a column of water four hundred feet high, is made about one and a quarter
inches thick, and a pipe of eighteen inches in diameter intended to stand the
same pressure is made about two and a quarter inches thick. The thickness
of the pipes is increased or decreased by giving the slate greater or less
lap; and when greater thickness than two and a quarter inches is required,
it is preferred to bind two successive layers of slate round the mould. For
sewer pipes, where there is little internal pressure, less binding iron and less
thickness of pipe is sufficient; these pipes may be so made as to be joined
otherwise than by spigott and faucett joints. For this purpose a collar may
be used, of wrought iron, left open like a dog collar, about quarter inch
thick, and about eight inches wide, its diameter when closed being about one-
quarter of an inch less than the outer diameter of the pipe; one end of this
collar has a lap rivetted on to it, as shewn by L, L, Figure 3, which is
furnished with two or more screws S, S, Figure 3, to screw the two ends of
the collar together; the collar with its laps and screws may be galvanized or
not. It is preferred to make these collars of iron, which has had ridges raised
on one side in the process of rolling, as in the flooring plates of engine rooms,
the ridged side forming the inner surface of the collar. When this collar is
to be put on, it is to be opened and expanded, to allow it to pass round the
pipes, and adjusted so as to cover each end of each pipe about four inches;
when thus in its place it is to be heated, by the application of two semicircular
heaters, and when the collar is hot enough for the ridges to sink into and
adhere to the asphalte of the pipes, its two ends are to be drawn tightly
together and the screws inserted. When this wrought-iron joint is intended

page_text: to be used, a cast-iron ring, of an L section, is to be fitted on to one end of the
cylindrical mould before the slates are bound on to it, and after the asphalte
has been poured in and cooled. Another cast-iron ring, of the same section,
previously heated to about one hundred and fifty degrees, and coated with
asphalte, is to be pressed on to the upper end of the pipe. These pipes may
also be joined, where there is to bo no internal pressure, by a faucett at one end
of the pipe formed by the projection of the cemented slates and a conical
spigott, as shewn at Figure 4. Junctions for branch pipes may be made
in intermediate cast-iron sockets, as shewn at Figure 6; and junctions for
branch pipes may also be made by cutting out a circular hole in the pipe by a
sheet-iron crown saw, worked with sand and water, and affixing in it a sockett
of cast iron, of the form shewn in section at Figure 5, or of any other suitable.
form, which, after being heated to about one hundred and fifty degrees, and
coated with asphalte, is pushed tightly into the opening made by the crown
saw.
In witness whereof, I, the said Bewicke Blackburn, have hereunto set
my hand and seal, this Thirtieth day of October, in the year of our
Lord One thousand eight hundred and fifty-four.
0 Witness,
JNO. ALCOCK.
BEWICKE BLACKBURN. (L.B.)