IMPROVEMENTS IN PUMPS, WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO ENGINES DRIVEN BY STEAM OR OTHER FLUID
Year: 1875

page_text: LETTERS PATENT to James Allan Brae, of London, in the County
of Middlesex, Civil Engineer, for the Invention of "IMPROVEMENTS
IN PUMPS, WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO ENGINES DRIVEN
BY STEAM OR OTHER FLUID."
Sealed the 14th March 1876, and dated the 18th September 1875.
PROVISIONAL SPECIFICATION left by the said James Allan Brae at
the Office of the Commissioners of Patents, with his Petition, on
the 18th September 1875.
I, JAMES ALLAN BRAE, of London, in the County of Middlesex, Civil
Engineer, do hereby declare the nature of my said Invention for " IM-
PROVEMENTS IN PUMPS, WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO ENGINES
DRIVEN BY STEAM OR OTHER FLUID," to be as follows:-
My Invention relates more particularly to pumps to be employed for
drawing and propelling liquids and gases, but it is also applicable to
motive-power engines, and it consists of an improved construction,
arrangement, and combination of the parts as herein-after described.

page_text: In carrying out my Invention I form a cylinder of any suitable
material (but by preference of cast iron), which cylinder is provided with
two covers, and also with an inlet and an outlet pipe respectively on its
opposite sides. In this cylinder I place a piston of much smaller
diameter, but fitting endways tightly between the two covers of the
cylinder, and carried by a shaft or axle supported by the before-
mentioned covers.
The piston has formed therein two or more radial slots, in which there
are fitted blades or pallets of the same length as the piston; and-carrying-
on each end at the corner nearest the centre of the piston round pins,
which fit into corresponding holes in blocks sliding in or traversing a
groove provided in each cover either eccentrically to the piston or of a
cam shape. One portion of the space left between the piston and the
external cylinder is entirely filled by a transverse stop placed between
the inlet pipe and the outlet pipe. Another portion of the space left
between the piston and the external cylinder (the centre of which is
exactly opposite the centre of the aforesaid stop, and is of sufficient
length to allow two blades or pallets to be within it at one time) has its
radius struck from the same centre as the eccentric or cam-shaped
groove. before mentioned.
i
The eccentric or cam-shaped grooves in the cylinder covers are placed
in such a manner as to entirely draw the blades or pallets (by means of
the slide blocks) within the piston in passing under the transverse stop,
and to push the blades or pallets out and against that portion of the
external cylinder already described as being opposite to the said stop.
The two remaining portions of the space between the piston and the
external cylinder, one communicating with the inlet pipe and the other
with the outlet pipe, are so made that ample space is obtained over tho
outer edge and on both sides of the advancing or retiring blades.
→In the case of revolving pumps or-engines consisting of one cylinder,
in which are contained two or more pistons fitting endways between and
carried by the two. cylinder covers, and each furnished with teeth-or
grooves, so that the several pistons engage with one another and propel
each other, it is proposed to make the following improvements, namely,
the configuration or curve of the teeth or grooves is formed' on the
involute principle, which imparts the maximum of strength with the
minimum-of-friction, whilst greatly-diminishing-the noise and-wear and

page_text: tear whilst working. Outside gearing is also entirely dispensed with,
and only one of the piston rods is allowed to project through the cylinder.
cover or covers, which I furnish with the necessary packing glands, and
also with an outside bearing if required to take the strain of the driving
strap or other power. This arrangement has the effect of dispensing
with all the other glands and their packings, and also with all the other
outside bearings.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Allan Brac in the Great Scal Patont
Office on the 18th March 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
ALLAN BRAE, of London, in the County of Middlesex, Civil Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of September, in- the
year of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said James Allan Brae, Her special
license that I, the said James Allan Brac, my executors, administrators,
and assigns, or such others as I, the said James Allan Brae, my
executors, administrators, or assigns, should at any time agree wiṭhı,
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 PUMPS, WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO
ENGINES DRIVEN BY STEAM OR OTHER FLUID," upon the condition (amongst
others) that I, the said James Allan Brac, my executors or admini-
strators, 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 James Allan Brae, do hereby
declare the nature of my said Invention, and in what manner the same

page_text: blocks of a V or other section, substantially in the manner and for the
purpose herein-before described, and as illustrated by my Drawings.
In witness whereof, I, the said James Allan Brae, have to this
my Specification set my hand and seal, this Fifteenth day of
March, One thousand eight hundred and seventy-six.
JAMES ALLAN BRAE. (L.S.)