AN IMPROVEMENT IN THE MANUFACTURE OF INVERT BLOCKS USED IN CONSTRUCTING SEWERS AND DRAINS
Year: 1858

page_text: LETTERS PATENT to Henry Doulton, of Lambeth, in the County of Surrey,
for the Invention of "AN IMPROVEMENT IN THE MANUFACTURE OF INVERT
BLOCKS USED IN CONSTRUCTING SEWERS AND DRAINS."
Sealed the 22nd September 1858, and dated the 26th March 1858.
PROVISIONAL SPECIFICATION left by the said Henry Doulton at the
Office of the Commissioners of Patents, with his Petition, on the 26th
March 1858.
I, HENRY DOULTON, of Lambeth, in the County of Surrey, do hereby
declare the nature of the Invention for "AN IMPROVEMENT IN THE MANUFACTURE
OF INVERT BLOCKS USED IN CONSTRUCTING SEWERS AND DRAINS," to be as
follows:
This Invention has for its object an improvement in the manufacture of
invert blocks used in the construction of sewers and drains. Heretofore, in
the manufacture of invert blocks, which are made by expressing clay through
moulding orifices, they have been formed in such manner as simply to form
butt joints, whereby fluid and other matters in drains or sewers are very
liable to pass through at the joints and to get into the hollow passages formed
through such blocks as well as into the ground in which such invert blocks
are laid, at the same time there is also no support given by one invert block
to another.
Now my improvement consists in applying a projecting lip at one end of

page_text: each of such blocks below the upper surface, and to remove a portion of the
partition or partitions which divide the under hollow part of such blocks into
separate hollow channels, so as to form a recess to receive the lip of the next
block.
In applying these projecting lips to the blocks it is advisable to set them a
short distance below the upper surface of the blocks, in order to allow of the
blocks being correctly laid, notwithstanding any slight change taking place in
the form of the blocks during burning; this allows also of a slight recess being
formed below the upper surface of the block to receive cement. By this
means the joints between invert blocks may with more certainty be made fluid-
tight, cement being introduced when laying the blocks on to the projecting
lips, and between the ends of such blocks. The lips or projections also cause
one block to be supported by and give support to the neighboring block.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Doulton in the Great Seal Patent Office on the 25th
September 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
Doulton, of Lambeth, in the County of Surrey, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of March, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-first year of Her
reign, did, for Herself, Her heirs, and successors, give and grant unto me, the
said Henry Doulton, Her special licence that I, the said Henry Doulton, my
executors, administrators, and assigns, or such others as I, the said Henry
Doulton, 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 "AN IMPROVEMENT IN THE MANU-
FACTURE OF INVERT BLOCKS USED IN CONSTRUCTING SEWERS AND DRAINS," upon the
condition (amongst others), that I, the said Henry Doulton, my executors or
administrators, by an instrument in writing under my, or their, or one of their
hands and seals, 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.

page_text: NOW KNOW YE, that I, the said Henry Doulton, do hereby declare the
nature of the said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following statement
thereof, that is to say :-
This Invention has for its object an improvement in the manufacture of
invert blocks used in the construction of sewers and drains. Heretofore, in
the manufacture of invert blocks, which are made by expressing clay through
moulding orifices, they have been formed in such manner as simply to form
butt joints, whereby fluid and other matters in drains or sewers are very liable
to pass through at the joints and to get into the hollow passages formed
through such blocks, as well as into the ground in which such invert blocks
are laid, at the same time there is also no support given by one invert block
to another.
Now
my improvement consists in applying a projecting lip at one end of
each of such blocks below the upper surface, and to remove a portion of the
partition or partitions which divide the under hollow part of such blocks into
separate hollow channels, so as to form a recess to receive the lip of the next
block. In applying these projecting lips to the blocks it is advisable to set
them a short distance below the upper surface of the blocks, in order to allow
of the blocks being correctly laid, notwithstanding any slight change taking
place in the form of the blocks during burning; this allows also of a slight
recess being formed below the upper surface of the block to receive cement.
By this means the joints between invert blocks may with more certainty be
mado fluid-tight, cement being introduced when laying the blocks on to the
projecting lips, and between the ends of such blocks. The lips or projections
also cause one block to be supported by and give support to the neighboring
block.
Having thus stated the nature of my Invention, I will proceed more fully
to describe the manner of performing the same. The object of the Invention
as above stated is to make the ends of invert blocks, whether for making or
for lining the lower parts of sewers or drains, so that part or parts projecting
from the end of one block may enter into a hollow part or parts of and bond
with the next block. With this object invert blocks may as heretofore be
made by being expressed through suitable moulding dies or orifices, which
may be formed suitable for producing plain sides or grooved and ribbed sides,
as may be desired, and the hollow passages made by the dies through the
invert blocks may be of any desired form. At one end of each of such invert
block I affix (before drying and burning) a projection or projections suitable
for entering an opening or openings made through or in the other end of the

page_text: next invert block; by these means the invert blocks in place of simply butting
together will bond into each other, and the joints where they come together
may have cement run in, so as to make close joints.
In witness whereof, I, the said Henry Doulton, have hereunto set my
hand and seal, this Twenty-fifth day of September, in the year of our
Lord One thousand eight hundred and fifty-eight.
Witness,
JNO. ALCOCK.
HENRY DOULTON. (L.S.)