IMPROVEMENTS IN ROTARY PUMPS
Year: 1857

page_text: LETTERS PATENT to David Thomson, of Pimlico, in the County of
Middlesex, Engineer, for the Invention of "IMPROVEMENTS IN ROTARY
PUMPS."
Sealed the 25th September 1857, and dated the 28th March 1857.
PROVISIONAL SPECIFICATION left by the said David Thomson at the
Office of the Commissioners of Patents, with his Petition, on the 28th March
1857.
I, DAVID THOMSON, of Pimlico, in the County of Middlesex, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN ROTARY
PUMPS," to be as follows:-
I construct centrifugal pumps with blades which are prolonged so as to
approach to or to join the central shaft or axis of the pump, and are made of
a screw or spiral form at that part. I also extend these screw blades beyond
the centrifugal wheel into the suction pipes or inlets of the pump case. The
water or other fluid is thus gradually drawn or guided into the wheel. This
pump may be immersed in the fluid to be raised or propelled, or it may be
placed above the fluid and provided with a suction pipe or pipes descending
into the fluid. I also construct rotary or centrifugal pumps with a wheel or
an arm or arms at the top of a hollow shaft or pipe, which is capable of being
raised or lowered while it is revolving; thus, to charge the pump with the
fluid, I lower it into the fluid, and I cause it to revolve, and I raise it out of
the fluid while it is in motion, keeping the lower end of the hollow shaft
below the surface of the fluid. The pump being thus charged, will continue,

page_text: to raise the fluid as long as it is kept in motion. The pump works in a
cylindrical case, having one or more gutters or recesses, into which the fluid is
thrown by the revolution of the pump. By raising the wheel to different
heights, the lift may be varied, and the fluid may be delivered at different
levels.
The machinery is easily accessible, and no foot valve is required, which is
particularly advantageous when pumping sewage and other liquids containing
foreign solid matters. For such purposes I also construct the interior of the
passages of such pumps without the sharp edges or abrupt angles, which render
ordinary centrifugal pumps liable to become clogged with straws and other
foreign matters in the sewage or other fluid.
I also avoid the use of a bottom valve for charging such rotary pumps when
working above the fluid to be raised by exhausting the air from the pump or
pump case and suction pipes by means of an air pump or other mechanical
apparatus, or by the condensation of steam, and thus causing the water to flow
up and fill them.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said David Thomson in the Great Seal Patent Office on the
28th September 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
THOMSON, of Pimlico, in the County of Middlesex, Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of March, 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 David Thomson, Her special licence that I, the said David Thomson, my
executors, administrators, and assigns, or such others as I, the said David
Thomson, 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 ROTARY PUMPS,"
upon the condition (amongst others) that I, the said David Thomson, 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 per-

page_text: formed, 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 David Thomson, 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, reference being had to the accompanying Drawings, and
to the figures and letters marked thereon, that is to say :-
I construct centrifugal pumps with blades which are prolonged so as to
approach to or to join the central shaft or axis of the pump, and are made of
a screw or spiral form at that part. I also extend these screw blades beyond
The
the centrifugal wheel into the suction pipe or inlets of the pump case.
water or other fluid is thus gradually drawn or guided into the wheel. This
pump may be immersed in the fluid to be raised or propelled, or it may be
placed above the fluid and provided with a suction pipe or pipes descending
into the fluid. I also construct rotary or centrifugal pumps with a wheel or
an arm at the top of a hollow shaft or pipe, which is capable of being raised or
lowered while it is revolving; thus, to charge the pump with the fluid, I lower
it into the fluid, and I cause it to revolve, and I raise it out of the fluid while
it is in motion, keeping the lower end of the hollow shaft below the surface of
the fluid. The pump being thus charged, will continue to raise the fluid as
long as it is kept in motion. The pump works in a cylindrical case, having
one or more gutters or recesses, into which the fluid is thrown by the revo-
lution of the pump. By raising the wheel to different heights, the lift may be
varied, and the fluid may be delivered at different levels. The machinery is
easily accessible, and no foot valve is required, which is particularly advan-
tageous when pumping sewage and other liquids containing foreign solid
For such purposes I also construct the interior of the passages of
such pumps without the sharp edges or abrupt angles, which render ordinary
centrifugal pumps liable to become clogged with straws and other foreign
matters in the sewage or other fluid. I also avoid the use of a bottom valve
for charging such rotary pumps when working above the fluid to be raised by
exhausting the air from the pump or pump case and suction pipe by means of
an air pump or other mechanical apparatus, or by the condensation of steam,
and thus causing the water to flow up and fill them.
matters.
Figure 1, Sheet I., of the accompanying Drawings, is a section at right
angles to the axis of a centrifugal pump constructed according to my Inven-
tion; Figure 2 is a longitudinal section of the same. The same letters refer to
similar parts in each Figure.

page_text: A is the case, having an opening or inlet on both sides of the wheel; B is
the shaft, carrying the central disc C, and the curved or spiral vanes or blades
D and the rings E, like those of the wheel of an ordinary centrifugal pump
or "Appold's pump." The shaft runs in the two bearings F and G. H, H,
are blades, which are joined to the roots of the blades D, D, or form one
piece with them. These blades H form prolongations of the curve of the
blades D at their commencement, and they gradually pass into a screw form
as they depart from the blades D and enter or pass through the inlet or
suction passages, until they terminate in the shaft at H. A sort of conoidal
screw propeller is thus formed, by which the water or other fluid is gradually
drawn or guided to the blades of the wheel. The number of the blades H
may be varied thus, in Figure 1 I have shewn one of these blades to cach
of the ordinary blades of the pump. In Figure 2 only two blades H are
shewn; they and the shaft are represented in elevation in this Figure. This
pump may be immersed in the fluid to be raised or propelled, or it may
placed above the fluid, and provided with a suction pipe or pipes descending
into the fluid.
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Figure 3, Sheet II., is an elevation of another centrifugal pump constructed
according to my Invention; Figure 4 is a sectional plan of the revolving part
or wheel. A is a cylindrical case or well, which is shewn in section; B is the
shaft, which revolves in a bearing ; C is the wheel, fixed to the shaft, and
consisting of two or more arms or pipes, with their ends bent into an angular
direction; or a complete wheel with a series of curved blades may be used. I
is the suction pipe, which revolves with the wheel, and passes through a
bearing G, fixed in the well; J is a bevil wheel, which is driven by another
bevil wheel K on the shaft L, or in any other convenient manner. The bevil
wheel J has a feather, which enters a longitudinal groove in the shaft B, which
is capable of sliding freely up and down through the wheel, which is kept in
its position by the bearings F and M. The shaft B is suspended by a swivel N
from a chain or bar O, by which it may be raised or lowered while in motion.
A circular gutter P is fixed in the side of the well, and other similar gutters
may be fixed at different heights when it is required to raise the liquid to dif-
ferent heights. The swivel N is prevented from revolving by means of a guide,
not shewn in the Drawing. The water or sewage or other liquid is allowed
to flow into the well, which is so placed that the wheel C of the pump may be
entirely immersed in the liquid. The wheel C is then caused to revolve by
means of the bevil wheels, and while it is revolving it is raised out of the
liquid by the chain or bar O, until it is on a level with the gutter P, or with
the gutter into which it is required to discharge. The pump being kept in

page_text: motion, continues to raise and discharge the liquid into the gutter; if, how-
ever, the motion of the pump be stopped the liquid falls out of it, and it is
necessary to lower it and charge it again as before. By this arrangement the
machinery is easily accessible, and no foot valve is required, which is par-
ticularly advantageous when pumping sewage and other liquids containing
foreign solid matters.
Figure 5, Sheet II., is an elevation, and Figure 6 is a transverse section,
of the wheel of another centrifugal pump constructed according to my
Invention. The passages D, D, are made without any sharp edges or angles
that can catch or entangle any solid bodies that may be in the sewage or other
liquid to be pumped, and the remainder of the circle is filled up, so as to form
a circular or nearly circular wheel, which is capable of revolving under water
with very little resistance. The form of the passages admits of considerable
variation, according to the speed of the wheel and the height of the lift; and
I sometimes make them of the form indicated by the dotted lines in Figure 6,
and they may be rectangular or circular, or of any other convenient form in
their transverse section; but in all cases they are to be made without any
sharp angles or edges.
This pump is not liable to become clogged with straws or other foreign
matters in the sewage or other liquid to be pumped, which are apt to get
caught by the edges of the blades of ordinary centrifugal pumps. This pump
may have two inlets or suction pipes or passages; but I prefer to make it with
only one inlet or suction pipe I, and to attach the shaft B to the other side, so
that the pump may not become clogged by straws or other foreign matters
winding round the shaft or becoming entangled in the arms or other con-
nections which would be required to connect the shaft to the wheel.
The pump shewn in Figures 3 and 4 may be made of a similar form to that
shewn in Figures 5 and 6, but this is unnecessary, as that pump has only to
revolve under water momentarily while it is being charged. The pump shewn
in Figure 5 and 6 is to be inclosed in a case. The suction pipe passes through
a stuffing box in the case, and descends into or communicates with the liquid
to be raised; or the suction pipe is detached from the wheel and fixed to the
case, and the wheel is made to revolve in close proximity to it; the shaft
may also pass through a stuffing box in the case. When a centrifugal pump
is fixed above the level of the liquid to be raised it is necessary to charge it
with liquid in order to put it into action. This has been effected by applying
a foot valve to the suction pipe which retains the liquid, which is then poured
into the case until the suction pipe and wheel are filled. This valve also
retains the liquid and keeps the pump charged when it is not in motion. It

page_text: has also been proposed to apply valves to the arms or circumference of the
wheel, and then to exhaust the air from the wheel and suction pipes by means
of an air pump. These valves are objectionable when pumping sewage and
similar liquids, for the reasons herein-before mentioned. I charge such pumps
in the following manner :-I apply a sluice valve or slide valve in the outlet
pipe leading from the case, which is made air-tight, and has a stuffing box for
the passage of the shaft. I connect an air pump with the case of the pump
and I exhaust the air, or I make a partial vacuum in the case of the pump
by filling it with steam and allowing the steam to condense. The liquid is
thus drawn up the suction pipe and the pump is charged; I then cause the
wheel to revolve, and while it is revolving I open the sluice valve in the outlet
pipe, through which the liquid is driven as long as the pump is kept in motion
at the proper speed. The sluice or slide valve does not interfere with the free
passage of straws and similar bodies, and being above water is easily accessible
for cleaning or repair. When the motion of the pump ceases, the liquid runs
back down the suction pipe and leaves the wheel empty. This may, however,
be prevented by closing the sluice valve before stopping the wheel. If the
outlet pipe communicates with the bottom of a cistern or reservoir from which
the liquid might return, such return is prevented by closing the sluice valve
before stopping the wheel; or in some cases an ordinary flap valve or conical
valve may be introduced in some part, or at the end of the outlet pipe, in
addition to the slide valve or the sluice valve, as, from this pipe being above
the level of the liquid to be raised, the valve will be more accessible than a
foot valve immersed in the liquid.
Having now described the nature of the Invention, and in what manner
the same is to be performed, I wish it to be understood that I do not confine
myself to the proportions of the various parts shewn in the Drawings, as the
same may be varied; but what I claim is,―
First, constructing centrifugal pumps with a conoidal screw propeller of
screw-formed blades placed in the inlet or inlets and extending from the shaft
or axis to some or all of the ordinary blades of the pump, of which they form
prolongations, as herein-before described.
Second, constructing centrifugal pumps in such manner that the wheel of
the pump is capable of being lowered into the liquid to be raised and
caused to revolve in the liquid and then lifted while still revolving and
raised to a sufficient height for delivering the liquid at the required level, as
herein-before described.
Third, constructing centrifugal pumps with the periphery of the revolving
wheel of a circular or nearly circular form (so as to be adapted for revolving

page_text: under water), in combination with passages presenting no sharp edges or arms
or abrupt angles for the arrest of solid matters, as herein-before described in
reference to Figures 5 and 6.
Fourth, constructing centrifugal pumps with close cases and with a sluice
or slide valve in the outlet pipe from the case, and with an air pump or other
exhausting apparatus communicating with the case in such manner, that the
wheel of the pump may be charged by exhausting the air from the case
without the application of any foot valve or any valve on the wheel, as herein-
before described.
In witness whereof, I, the said David Thomson, have hereunto set my
hand and seal, this Twenty-eighth day of September, in the year of
our Lord One thousand eight hundred and fifty-seven.
Witness,
CHARLES COWPER,
20, Southampton Buildings,
Chancery Lane, London.
DAVID THOMSON. (L.S.)