IM- PROVEMENTS IN ROTARY PUMPS
Year: 1872

page_text: LETTERS PATENT to William Edwards, of No. 43, Hungerford Road,
Holloway, in the County of Middlesex, for the Invention of "IM-
PROVEMENTS IN ROTARY PUMPS."
Sealed the 30th May 1873, and dated the 14th December 1872.
PROVISIONAL SPECIFICATION left by the said William Edwards
at the Office of the Commissioners of Patents, with his Petition,
on the 14th December 1872.
I, WILLIAM EDWARDS, of No. 43, Hungerford Road, Holloway, in
the County of Middlesex, do hereby declare the nature of the said In-
vention for "IMPROVEMENTS IN ROTARY PUMPS," to be as follows :—
This Invention relates to improvements in the construction of and
arrangement of parts connected with rotary pumps of that kind which
operate by means of two cog wheels caused to revolve within a case in
opposite directions, so that the cogs of the one wheel enter the spaces

page_text: between the cogs of the other wheel, the movement of the two wheels
being made to,accord by suitable gearing.
In the Specification of a Patent granted to Hugh Forbes; dated the
24th September 1867, was described a mode of forming the inlets to and
outlets from the case of such pumps, by making elongated apertures to the
supply and discharge pipes. One part of the present Invention consists
in making these apertures both elongated, so as to extend the whole
width of the case, and also of a breadth equivalent to the diameter of the
pipes, or nearly so, with a rib or fin extending across the middle of the
aperture in a direction parallel to the axes of the rotating wheels. By
this arrangement the fin or rib being made with a sharp edge towards
the pipe the fluid enters the case of the pump or flows from it into the
discharge pipe freely in a divided stream. Also the part of such rib or
fin presented towards the interior of the case being made to correspond
with the circular form of such case on each side, presents a surface of
contact to the cogs passing it, which acts to check leakage backwards
like the lap of a stop-cock or slide.
Another part of this Invention consists in casing in the gearing wheels
which connect the shafts of the two rotating cog wheels. These gearing
wheels are usually fixed on the shafts outside of the pump casing, and
are exposed to dirt, grit, and other impediments, besides presenting a
source of danger to persons working the pump.
According to my improvement I cover these wheels with a casing of
form similar to the casing of the pump, and attached to the side thereof,
which casing may be kept charged with oil for the purpose of lubricating
the bearings of the shafts and the teeth of the gearing.
As it is important that the bearings of the shafts should have consider-
able breadth for the purpose of diminishing wear, and preventing the
cutting and seizing of the metal surfaces, I make the sides of the pump
case with bosses projecting inwards into cavities formed in the ends of
the revolving cog wheels, and I bore out these bosses to receive the
shafts, bushing them when required with brass or other suitable bearing
metal. Thus breadth of bearing is secured without adding to the width
of the pump by bosses projecting outwards, and the bearings act more
directly to support the working strain,

page_text: In working such rotary pumps for liquid it is necessary to charge them
first with the liquid. When their working is stopped, the liquid flows
from them, and they have to be charged again, unless they are provided
with foot valves to retain the liquid charge. In order to render such
foot valves unnecessary, I carry the suction pipe of the pump down into
a well or receiver, from the upper part of which the supply pipe is
branched. As this well or receiver is never emptied below the level of
the supply pipe the suction pipe of the pump remains always immersed
in liquid, and when the pump is started it cannot draw air, because its
suction pipe is sealed by the liquid from the atmosphere. The said well
or receiver also forms a receptacle for dirt, which might otherwise be
drawn through the pump and injure its working parts, and a capped hole
may be formed in the side of the well or receiver for the purpose of
occasionally cleansing the same.
The arrangement of suction pipe above described is especially applic-
able in the case of ships' pumps where foot valves are objectionable,
because they are apt to be rendered ineffective by matters preventing
them from closing.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Edwards in the Great Seal Patent Office
on the 12th June 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
EDWARDS, of No. 43, Hungerford Road, Holloway, in the County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourteenth day of December, in the
year of our Lord One thousand eight hundred and seventy-two,
in the thirty-sixth year of Her reign, did, for Herself, Her heirs and
successors, give and grant unto me, the said William Edwards, Her
special license that I, the said William Edwards, my executors, adminis-
trators, and assigns, or such others as I, the said William Edwards,
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

page_text: 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
ROTARY PUMPS," upon the condition (amongst others) that I, the said
William Edwards, 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 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 William Edwards, 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, reference being had to the accom-
panying Sheet of Drawings, and to the figures and letters marked
thereon, that is to say :-
This Invention relates to improvements in the construction of and
arrangement of parts connected with rotary pumps of that kind which
operate by means of two cog wheels caused to revolve within a case in
opposite directions, so that the cogs of the one wheel enter the spaces
between the cogs of the other wheel, the movement of the two wheels
being made to accord by suitable gearing.
In the Specification of a Patent granted to Hugh Forbes, dated the
24th September 1867, was described a mode of forming the inlets to and
outlets from the case of such pumps, by making elongated apertures to
the supply and discharge pipes. One part of the present Invention
consists in making these apertures both elongated, so as to extend the
whole width of the case, and also of a breadth equivalent to the diameter
of the pipes, or nearly so, with a rib or fin extending across the middle
of the aperture in a direction parallel to the axes of the rotating wheels.
By this arrangement the fin or rib being made with a sharp edge towards
the pipe the fluid enters the case of the pump or flows from it into the
discharge pipe freely in a divided stream. Also the part of such rib or
fin presented towards the interior of the case being made to correspond
with the circular form of such case on each side presents a surface of
contact to the cogs passing it, which acts to check leakage backwards
like the lap of a stop-cock or slide.

page_text: Another part of this Invention consists in casing in the gearing wheels
which connect the shafts of the two rotating cog wheels. These gearing
wheels are usually fixed on the shafts outside of the pump casing, and
are exposed to dirt, grit, and other impediments, besides presenting a
source of danger to persons working the pump.
According to my improvement I cover these wheels with a casing of
form similar to the casing of the pump, and attached to the side thereof,
which casing may be kept charged with oil for the purpose of lubricating
the bearings of the shafts and the teeth of the gearing.
As it is important that the bearings of the shaft should have consider-
able breadth for the purpose of diminishing wear, and preventing the
cutting and seizing of the metal surfaces, I make the sides of the pump
case with bosses projecting inwards into cavities formed in the ends of
the revolving cog wheels, and I bore out these bosses to receive the
shafts, bushing them when required with brass or other suitable bearing
metal. Thus breadth of bearing is secured without adding to the width
of the pump by bosses projecting outwards, and the bearings act more
directly to support the working strain.
In working such rotary pumps for liquid it is necessary to charge
them first with the liquid. When their working is stopped the liquid
flows from them, and they have to be charged again unless they are
provided with foot valves to retain the liquid charge. In order
to render such foot valves unnecessary I carry the suction pipe of
pump down into a well or receiver, from the upper part of which the
supply pipe is branched. As this well or receiver is never emptied below
the level of the supply pipe, the suction pipe of the pump remains
always immersed in liquid, and when the pump is started it cannot draw
air because its suction pipe is sealed by the liquid from the atmosphere.
The said well or receiver also forms a receptacle for dirt which might
otherwise be drawn through the pump and injure its working parts, and
a capped hole may be formed in the side of the well or receiver for the
purpose of occasionally cleaning the same.
The arrangement of suction pipe above described is especially applic-
able in the case of ships' pumps, where foot valves are objectionable
because they are apt to be rendered ineffective by matters preventing
them from closing.

page_text: Fig. 1 represents a transverse section, and Fig. 2 a sectional plan of a
rotary pump of the kind described above, and Fig. 3 is a vertical section
of the suction pipe for such pumps, shewing the improvements in con-
struction to which this Invention refers.
The suction orifice A and the discharge orifice B being made of elon-
gated form to extend the whole width of the casing are each divided by
a rib a and 6 of a sharpened form at its outer edge, so as to present little
resistance to the flow of fluid, and on its inner face hollowed to the
circles of the revolving cogs, so that it acts as a lap to diminish leakage
past these cogs. The gearing wheels C and D by which the two cog
wheels are connected are enclosed in a casing E, which may be charged
with oil. Thus friction is reduced and the wheels are protected from
dirt and grit, while the casing serves as a shield to protect persons using
the pump from being injured by the revolving gearing. The cog'wheels
Fand G are recessed at the ends so as to give room for bosses fand g
to project from the interior of the casing, the object of these bosses being
to give wider and steadier bearings to the working shafts, for which
purpose they may be bushed with gun metal or other suitable bearing
metal. The suction pipe H, Fig. 3, is made to dip nearly to the bottom
of a well or basin formed vessel I, to which the supply pipe J is con-
nected at a level above the bottom of this vessel. Thus when the supply
pipe is emptied the fluid remaining in the hollow of the vessel I serves
to seal the interior of the pump from the atmosphere. As the well I
serves as a receptacle for dirt it may have an orifice with cap K to
give access for cleansing.
Having thus described the nature of the said Invention, and in what
manner the same is to be performed, I claim,-
First. The use in rotary pumps which operate by means of two cog
wheels caused to revolve within a case of ribs dividing the inflow and
outflow orifices so formed and arranged as to act as a lap to the revolving
cogs, substantially as herein described.
Second. Enclosing the gearing wheels of pumps such as are above

page_text: Third. Widening the bearings of the working shafts of pumps such as
are above referred to, by means of bosses projecting inwards from the
casing into recesses provided in the ends of the cog wheels, substantially
as herein described.
Fourth. Providing the suction of pumps, such as are referred to above,
with a well, whereby the interior of the pump is sealed when the supply
pipe is empty, substantially as herein described.
In witness whereof, I, the said William Edwards, have here-
unto set my hand and seal, this Twelfth day of June, in the year
of our Lord One thousand eight hundred and seventy-three.
WILLIAM EDWARDS. (L.S.)