IMPROVEMENTS IN APPARATUS FOR THE RAISING AND PROPELLING OF WATER OR OTHER FLUIDS, APPLICABLE LIKEWISE AS A SHIP PROPELLER, MOTIVE POWER, FAN, METER, AND FOR OTHER PURPOSES
Year: 1866

page_text: LETTERS PATENT to Hugh Forbes, of 184, Euston Road, N.W., Parish of
St. Pancras, County of Middlesex, for the Invention of "IMPROVEMENTS
IN APPARATUS FOR THE RAISING AND PROPELLING OF WATER OR OTHER FLUIDS,
APPLICABLE LIKEWISE AS A SHIP PROPELLER, MOTIVE POWER, FAN, METER, AND
FOR OTHER PURPOSES."
Sealed the 5th April 1867, and dated the 9th October 1866.
PROVISIONAL SPECIFICATION left by the said Hugh Forbes at the
Office of the Commissioners of Patents, with his Petition, on the
9th October 1866.
I, HUGH FORBES, of 184, Euston Road, N.W., Parish of St. Pancras, County
of Middlesex, do hereby declare the nature of the said Invention for "IMPROVE-
MENTS IN APPARATUS FOR THE RAISING AND PROPELLING OF WATER OR OTHER FLUIDS,
APPLICABLE LIKEWISE AS A SHIP PROPELLER, MOTIVE POWER, FAN, METER, AND FOR
OTHER PURPOSES," to be as follows:-
Firstly, these improvements consist in a peculiar construction and arrange-
ment of the teeth (or cogs) and their intermediate spaces, having reference
to the more perfect gearing of the same on that part where the respective
pitch circles of each drum meet.

page_text: Secondly, in such construction and arrangement of the teeth and spaces on
the drums as will enable the teeth to fit more completely than hitherto into
the corresponding spaces, and thus more effectually to exhaust the air, and
likewise impede the return of the fluid which has once been raised.
Thirdly, in the gearing of the outer wheels on their respective pitch circles,
and in conformity with the requisite motion of the drums, when such outer
wheels are used.
pressure
of
Fourthly, in the construction of the drum casing, whereby that
the water against the teeth which is antagonistic to the rotation of the drums
in raising and propelling (or as it is often termed, forcing) is lessened, while
certain other pressure of the fluid corresponding with the rotary motion of the
drums is not prevented.
Fifthly, in stopping the leakage which is often considerable from the upper
parts of the drum casing.
Sixthly, in the side orifices for introducing the drums into the casing, so
that they can be extracted or changed without dismounting the drum casing.
Seventhly, this my improved apparatus may, to a certain extent, be made
self-acting and maintaining, and further it can be used as a motive power, and
may become available for several purposes.
Rotary pumps composed of two drums (or broad wheels) inside a casing,
having the teeth of each drum to gear into the corresponding spaces between
the teeth of the opposite drum have been frequently tested and abandoned, on
account partly of the friction and consequent wear of the teeth, and partly
the rate of velocity at the tip (or extremity) of each tooth is greater than
that at the root (or bottom) of each space, and in consequence of this
variation in the respective velocities (a result produced by the outer circle or
the circumference of the tips of the teeth, being greater than the inner circle
marking the roots or bottoms of the spaces,) the fitting of the teeth into the
spaces has not hitherto been sufficiently exact to ensure the efficient action of
the pump. Attempts have been made to overcome the wear upon the teeth of
the drums by causing the rotary motion to be communicated to them through
the medium of wheels gearing into each other outside the drum casing, but
these efforts have not (till my present Invention) proved successful, for
the reason that the rate of velocity is (as just explained) greater at the tips of
the teeth than at their roots (the bottoms of the corresponding spaces) into
which they gear, and the velocity of the pitch circles also differs both from
that of the tips of the teeth and that of the bottoms of the spaces; all which
inconveniences operate just as much on the outside wheels as on the drums
(or inner wheels) themselves.

page_text: My improvements in the construction and arrangement of the teeth and
spaces are such that the teeth of one drum (as the pair revolves) shall bear
upon the spaces of the other drum on that part where the pitch circles of the
two meet at the point E of the (dotted) line of centres F, G, (Fig. 1), or in
other words, that the two drums shall gear on the point of contact of their
pitch circles. With a view to the more perfect and uniform working of each
tooth into its corresponding space, in the manner above described, I prefer
that the teeth take a spiral direction from end to end of the drum, and that
the degree of spiral slope from one end to the other of the drum be equal to
the distance between the tip of one tooth and the tip of the next on the same
drum. The teeth and spaces could be constructed so as for them to describe
a curve or other arbitrary direction, provided the teeth and spaces of each
drum (of the same pair) so perfectly coincide that they gear correctly into
each other. The two drums (of a pair) may be of different diameters, pro-
vided the teeth and spaces of the one correspond in shape, size, and direction,
and gear smoothly into those of the other drum, and that the drum casing be
constructed so as to conform with the shape of the pair, but I prefer that the
two drums be of equal dimensions. As the rate of velocity of the tip H,
(Fig. 1) of each tooth must necessarily exceed that of the root of each space K,
some amount of play between the said teeth and their opposite spaces must be
allowed whence the escape of a portion of fluid from the chamber B and its
return to the chamber A will happen. With a view more effectually to obstruct
such communication I cover all or part of the surfaces of each of the spaces
(I prefer to do this from pitch line to pitch line), and I fasten to the drums
securely and hermetrically the edges of the said covering (Figs. 2 and 3)
leaving, however, the remainder of the covering free from adhesion to the
drum. Beneath the said covering I allow a small quantity of atmospheric
air to remain without the possibility of its escape from between the covering
and the drum, or I might introduce gas, spirit, water, or other fluid, but
I prefer to adopt air for the purpose. As each tooth (when the drums
rotate) presses upon one more than on another part of the space into
which it gears, the above-mentioned covering (being flexible) will yield
on the spot so pressed, while the confined air will cause the portion not
indented to swell, by which arrangement I ensure constant contact
between each tooth and space as they alternately gear into each other.
Suction is through this contact more speedily and surely obtained, the
passage of water by the pre-existing interstices is prevented, and the
action of the pump is consequently improved. Since the pressure of a tooth
upon the flexible covering of a space (Fig. 3) would as the drums rotate be

page_text: liable to force the confined air towards the edge (at or near the pitch circle
where I prefer that it be fastened to the drum), and thus might burst the
covering, I prefer that each space should have one or more indentations or
grooves in the drum, which would allow the confined air to pass to that part
not pressed, and I prefer that these grooves be more considerable towards the
ends of the drums than the centres. The teeth also may be covered in a
similar manner, but the necessity for such covering on them is less when the
spaces are provided with it. If both teeth and spaces are so covered I prefer
that the flexible materials should be drawn somewhat tighter over the former
than is done for the latter. Communication for the confined air beneath the
covering of the teeth and that of the spaces would not render the pump
absolutely useless, since the pressure of the water on the other parts would also
be considerable, but I prefer to construct my covering with no passage for the
confined air beyond the pitch circle of each tooth and space.
The coating which confines the air, as above described, can be made of any
flexible substance through which air cannot escape, or which is impervious to
gas, spirit, water, or such other fluid as may be inserted between the drum and
the coating or covering above described. I prefer to employ bladder (single
thickness or more) and to strengthen the same with linen, silk, cloth, or other
meterials, which I cause to adhere by elastic glue or other suitable compound,
though they might be used without adhesion the one to the other or to the
bladder.
As already stated attempts have been made to avoid the friction of one
drum against the other by causing them to rotate through the action of wheels
outside the drum casing, which has not, however, been satisfactorily accom-
plished because the velocity of the tips of the teeth is superior to that of the
roots, and each tooth consequently requires a larger spaco while the drums
rotate than it can fill whilo the drums are stationary, hence the movement of
the outside wheels cannot (in regard to the teeth and spaces) exactly corre-
spond with that of the inside drums unless the teeth and spaces of the former
be in precise conformity with those of the latter. To obviate this difficulty
I construct my drums so that their respective pitch circles (dotted) U, U,
Fig. 1, meet (or very nearly so) at the point E, where they are intersected by
the (dotted) line of the centres F, G; and I construct my teeth and spaces,
by preference, with a spiral thread or direction on the drums S, S, though
a curve or other arbitrary direction given to the teeth and spaces would
not destroy the efficiency of the pump. The shape of the teeth and spaces [
prefer to be semicircular (Figs. 1, 2, and 3) upon the drums S, S, though
epicycloidal, bypocycloidal, involute curves, or other arbitrary forms might be

page_text: adopted. As to the teeth and spaces of the outside or outer wheels (when
such are employed outside of the casing) they may be of any convenient shape
or size, and may be put upon the said outside wheels in any direction
(straight, curved, oblique, or other), provided the said outside wheels gear
upon the point where the line of centres intersects their respective pitch
circles, because that will correspond with the working of the drums within the
casing, which likewise keep in contact with each other and gear upon their
pitch circles at that point intersected by their line of centres. Those drums,
however, which revolve upon their axles through the action of the outside
wheels might be prevented from coming into quite close contact at their
pitches without the pump being rendered useless, because the communication
from the chamber B to chamber A would (as already described) be
impeded by the inflated lining or coating, Fig. 3. When, however, the drums
do not revolve through the action of the wheels outside the casing the drums
themselves will gear upon (or extremely near to) the point E where their
respective pitch circles (dotted) U, U, Fig. 1, are intersected by the line of
centres F, G. And I wish it to be clearly understood that when I say that
the drums (and the same regards the outside wheels) should gear upon the
point E where their line of centres F, G, intersects their pitches (or extremely
close thereto), I prefer that the contact and gearing be exactly on that spot,
nevertheless if a slight deviation were to occur rotation could be obtained,
though ever so trifling a deviation, from the point E, would be an imperfection,
which with careful workmanship need not occur, and must entail greater play
between tooth and space.
I construct my drums and casing of that relative size and shape in regard
to each other that the former come as close as possible in contact with the
interior of their casing without scraping it, and I prefer to prolong that contact
from the lower chamber A, Fig. 1, to the points a and a", where commences
the upper chamber B, so that the teeth touch (or nearly so) on the parts of
the drum casing from d to a and d' to a"; and I also make my drums and
their casing to fit endways of the drums S, S. While the drums rotate rapidly
that motion of spinning round on their axles has a tendency to check and
even prevent the escape of fluid from B to A by the drum ends, unless the
pressure from the outlet tube D be excessive. For the more complete pre-
vention of such passage, and the consequent loss of water, the flat ends of the
drums inay (as well as the teeth and spaces) be conted with linen, india-
rubber, cloth, or other substance, and 1 prefer that the materials used for this
purpose should have a nap upon them, as cloth or velvet for instance. Tho
casing itself might also be coated in a similar manner, but I prefer that two

page_text: fabricks, each having a nap on its surface, do not come in contact because of
their wear from the friction.
The axles or spindles can be set so that the drums on them work hori-
zontally, as shewn in the Drawing (Fig. 1), which is the position I prefer for
them; though the pump would act if the drums were placed in a perpendicular
or other position on their axles.
In constructing my casing P, P, P, P, Fig. 1, I prolong the segments of
the outer circles C, which are the circumferences of the tips of the teeth, or
in other words, the diameters of the drums from tooth tip to tooth tip, and are
parts of the inner surface of the casing, and I continue them (the segments
of C) on each side of the casing P, P, to or even beyond the point a on the
one side, and a" on the other side along the outer edges or tips of the teeth
of each druin, instead of ceasing the contact of the drums with their casing
at Land L, Figs. 1 and 4.
According to the old mode of construction (indicated by the dotted lines
L, R, and L, R) the pressure of water against the faces of the teeth on the
upper part of the drums (as shewn by the straight featherless arrows c, c, c, c,)
is allowed to act in an opposite direction to the rotation of the drums S, S,
(as shewn by the curved arrows x and x), consequently a greater amount of
force is required to overcome this resistance than would be necessary when
that resistance is diminished. By prolonging the contact of my drums with
their casing to the points a and a", I add to the old form of casing the pieces
L, R, a, and L, R, a", whereby the pressure from the weight of the water in
the discharge tubing D is prevented from affecting those teeth numbered 1,2,
and 8 (Figs. 1 and 4); for unless so impeded the adverse pressure (arrows
c, c, c, c,) would act as far as T and T upon the two drums S and S ; but
while I thus protect my drums from the pressure of water (or other fluid) in
a sense contrary to their rotary motion I allow that pressure which is favour-
able to their rotation (as shewn by the arrows b, b,), consequently a minor
degree of force becomes necessary to rotate my drums. When an apparatus
is constructed which may be liable to sustain so great a weight of water as
might endanger the bending of the prolongations L, R, a, and L, R, a", the
casing should be strengthened by an augmentation of the metal or other
materials, as shewn by the (dotted) line R, a, or the prolongation may be
diminished, as shewn by the (dotted) line R, a'.
Another of my improvements in the casing regards the prevention of
leakage to which the upper joints are more particularly liable when the
apparatus is subjected to extreme pressure of water in the upper chamber
(B, B¹, Fig. 1, and B, Fig. 4). To obviate this inconvenience I cast (or

page_text: otherwise construct) in one piece my casing P, P, P, P (Fig. 1) and Y, Y,
with the opposite side to Y, Y, (Fig. 5) from N, N, upwards with a hollow
therein of the size of the united drums, and I insert my drums into their
places in the casing from the bottom instead of the side, adjusting afterwards
through the side Y, Y, the spindles F and G, securing them in their stuffing
boxes,, Fig. 5, after which I introduce in their places and firmly secure
the pieces lettered M and M (Fig. 1) which need not fit quite close to the
teeth tips of the drums (and indeed if M and M were omitted the pump
would not be rendered useless) and then I fasten, by soldering, welding, or
otherwise the bottom plate N, N, to the upper parts P, P, P, P, Y, Y, and
the opposite side to Y, Y, adding lastly the orifice O which serves as the
ingress of the fluid. The two sides of the casing P, P, P, P, and the side
opposite to Y, Y, could be cast or otherwise constructed in one piece, and
the remaining side Y, Y, could subsequently be secured to it, or the pieces
could all be seperately prepared and could subsequently be solidly fastened
together, the main object being to ensure joints through which water cannot
by any possibility escape let the pressure from the upper tubing and egress
orifice D be ever so severe. As it might be necessary to repair or change one
or both of the drums, I construct in the side Y, Y, (Fig. 5) a circular orifice
V, the circumference of a drum, and through which a drum can be inserted
into the casing. This orifice I close by a similarly sized circular piece
screwed into the casing or otherwise securely fitted. On the opposite side of
the casing I make a similar arrangement (dotted circle W) through which
I can either withdraw or introduce into its proper place the other drum.
Thus without dismounting the casing or disturbing its stand 9, 9, or deranging
the inlet tubing O, the drums S, S, can be taken out and refitted. Were the
pump placed in such a situation (on board a steamer for propelling purposes
that might happen) as would render the extraction of a drum difficult except
from one side of the casing, the two orifices V and W could be made on the
same side, but that would require extreme nicety of workmanship and fitting,
because one circle would bite into the other. As the raising of water by this
apparatus is effected by first exhausting the air from the tubing below the
inlet orifice O and from the chamber A (Fig. 1) and thus drawing up water
by suction into the casing and the troughs or spaces of the drums it is evident
that the operation must be performed quicker if water be already in the
chamber B. A valve (or more than one) could therefore be fixed in the
casing by preference at the bottom of the chamber A and immediately over the
inlet orifice O, or it could be put in the tubing (or in both tubing and casing)
to retain the water once raised, and thus ensure a more speedy flow. The

page_text: raising or lifting of water beyond the outlet orifice D partakes rather of the
nature of forcing or propelling. When this apparatus is applied as a means
of propelling vessels through the water, the very close fitting of the teeth of
the drums into their corresponding spaces is not of such importance as it
would be in raising water by suction. It is however very desirable that all
parts fit well and that a reflux of water between the teeth and spaces be not
allowed, because the power of the apparatus as a propeller for ships would be
diminished in the samo proportion as any of the water in the exit (or upper)
chamber B would be permitted to return to A, instead of issuing in the full
quantity at the tubing D, Fig. 1. Since the exact quantity of water or other
fluid which each space or trough on the drums conveys into the upper
chamber B, B', Fig. 1, can be easily ascertained, the amount raised by the
apparatus can be correctly calculated and registered by fixing to an axle
(For G) a suitable index, whereby the revolutions of the drums may be
counted. By diminishing the pressure of the water acting in the senso
contrary to the rotation of the drums (shewn by the arrows c, c, c, c, as already
explained) and on the other hand by retaining the pressure of the water in the
direction favourable to the said rotation (arrows b, b, Fig. 1) little physical
strength is required to make the drums rotato and deposit in the upper
chamber B, B', successive troughs or spaces filled with water. By obstructing
the return of the water from B to A it is obvious that whatever fluid may
have been deposited in the upper chamber B, must (as more continues to bo
brought in by the successive revolutions of the drums) find an outlet by the
only orifice D, though the height to the top of the tube were to be considerable,
and thus issuing from the top of a high tube the water from the apparatus may
bo so directed as to flow upon a wheel (or into a cistern and thence on a
wheel) which it would cause to revolve, which wheel being made to act on a
pinion would turn or help to turn the axles of the drums or of their outside
wheels, whereby the apparatus would become to a certain extent self-acting
and maintaining, that is to say, it would so become after the tubing and
recipients for water connected with the side of the downward course of the
said wheel had been first filled with water ready for action to occur so soon
as a bolt or other stay were withdrawn to allow the wheel (its cups of one side
being already filled) to revolve by the flow of water into its cups as each cup
arrives at the top. It is true that the greater the height of the egress tube D
the greater must be the pressure of the water on the faces of the teeth of the
drums; but in like proportion do the teeth 11' become influenced by that
downward and favourable pressure (arrows b, b) and the rotation of the drums
becomes proportionably easy. And it is self-evident that the arrangement

page_text: which would enable the water of the apparatus to turn the axles and revolve
the drums of the apparatus could also be used as a power to give motion to
machinery.
When my improved apparatus is employed to pump water from mines or
for any
other purposo which requires fluid to be raised, lifted, or forced to a
very great height, a succession of pumps can be arranged at stages, rather
than allow so heavy a weight of tubing to bear upon the drum casing, and
such a large column of water to press upon chamber B, B', Fig. 1, so as to
require extreme strength with proportionate thickness of metal, for though the
weight of water acting on the casing might be mitigated by valves, they would
be inconvenient for such a purpose, and might get out of order. Each stage
(when the pumping is to be done by stages) should have its own apparatus,
drawing from a lower and forcing to a higher reservoir till the top of the mine
(or other place) be reached, and the water flow out. Each apparatus in the
successive stages could be arranged so as to be (to a certain extent) self-
acting and maintaining (as described already); or the requisite rotation could,
seperately to each apparatus or collectively, be communicated to the drums by
band, horse, or other power below or above ground.
My improved apparatus may be used to pump air and force it through
tubes for the purposes of ventilation, or through a nozzle as a bellows or fan
would act. When so employed the whole apparatus may be constructed of
very light materials, and the drums as well as the casing can be covered
with cloth, having the nap of the cloth or velvet inside the casing laid so close
as to touch without scraping upon the nap on the tips of the teeth. When
used as a fan I prefer to adopt outside wheels to cause the drums to rotate,
and this I do chiefly on account of the slightness with which the drums aro
constructed.
And in order that my Invention may be more fully understood I proceed
to describe the Drawing hereunto annexed.
DESCRIPTION OF THE DRAWING.
Figure 1 shews a section of the casing and drums. A is the lower chamber
(that of ingress) whence the water is carried to the chamber B by the spaces
or troughs K; B is the upper chamber of the casing into which the water is
carried by the spaces K; B' is the higher division of the chamber B of egress;
Cis the segment of the circle of the circumference of the tops or tips of the teeth
of the drums, marking also the interior surface of that part of the casing; Dis
the egress or outlet orifice with thread for screwing in the tubing for the egress
of the water from the chamber B B'. E is the point of
the itah

page_text: circles of the drums; F and G are the axles or spindles of the drums; II, II
are the upper parts of the teeth or cogs of the drums; K, K, are the lower
parts of the spaces of the drums below the pitch; L and L, perpendicularly
above the axles F and G are the points where the upper chamber B
commences in ordinary pumps of this description; M and M aro pieces
inserted in the casing rather than allow an unnecessary accumulation of air;
N, N, is the plate or bottom on which is secured the casing P, P, P, P, Y, Y,
and the opposite side to Y, Y (in Fig. 5); O is the lower orifice or inlet, with
thread for screwing in the tubing; P, P, P, P, is portion of the sides and
upper part of casing; 9, 9, is the stand (slab or table) on which is usually
fixed the apparatus for working; R, R, is the rim of the upper chamber B';
R, L, is the (dotted) line shewing the shape of the upper chamber in ordinary
pumps of this description; S and S are the drums or broad toothed wheels;
T, T, are the points up to which the pressure of the water from chainber B
reaches in ordinary pumps of this description; U and U are the pitch circles;
a and a" are respectively the ends or extreme points of the prolongations
R, L, a, and R, L, a", intended to protect the faces of those teeth numbered
1, 2 and 3, from the adverse pressure of the water, which otherwise would
operate upon the teeth so numbered; b, b, are arrows shewing the
pressure of
the water in a sense favourable to the rotary movement; c, c, c, c, are arrows
shewing the pressure in the sense unfavourable to the rotation of the
drums; d and d are the places where I prefer the commencement of contact
between the teeth and the drum casing; and are curved arrows indicating
the direction of the rotary motion of the drums. The arrows without letters
shew the direction of the flow of water from the inlet O to the outlet D.
Fig. 2 shews a segment of pitch circle and drum. II, tooth; K, space;
U, U, pitch. The dotted lines over II and inside of K show the inflated
coating.
Fig. 3 shews a segment of pitch circle and drum. K, space; U, pitch.
The dotted line shews inside the space K the inflated coating with pressure at
the point e.
Fig. 4 shews part of the section of the ordinary rotary pump with my
improved prolongation of contact from L to a in dotted lines. C, segment of
circle shewing the circumference of the drums, also describing the interior
surface of the casing; L, L, are the terminations of contact of the teeth with
the inside surface C of the drum casing; L, a, dotted line shewing the
prolongation of circle C in my apparatus; R, R, S, S, T, T, b, b, c, c, c, c,
same as in Fig. 1.
Fig. 5 shews a view of the exterior of one side of my casing. D, F, G,

page_text: L, L, N, N, O, 9, 9, the same as in Fig. 1; V, circle shewing the orifice for
the admission of a drum into the casing; W, dotted circle shewing the place
for the corresponding orifice on the opposite side of the casing to take out or
let in the other drum.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Hugh Forbes in the Great Seal Patent Office on the
9th April 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HUGи
FORBES, of 184, Euston Road, N.W., Parish of Saint Pancras, County of
Middlesex, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Ninth day of October, in the year of our Lord One
thousand eight hundred and sixty-six, in the thirtieth year of Her reign,
did, for Herself, Her heirs and successors, give and grant unto me, the
said Hugh Forbes, Her special licence that I, the said Hugh Forbes,
my executors, administrators, and assigns, or such others as I, the said Hugh
Forbes, 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
APPARATUS FOR THE RAISING AND PROPELLING OF WATER OR OTHER FLUIDS,
APPLICABLE LIKEWISE AS A SHIP PROPELLER, MOTIVE POWER, FAN, METER, AND
FOR OTHER PURPOSES," upon the condition (amongst others) that I, the said Hugh
Forbes, 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.
NOW KNOW YE, that I, the said Hugh Forbes, do hereby declare
the nature of my 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 :-
Firstly, these improvements consist in a peculiar construction and arrange-
ment of the teeth (or cogs) and their intermediate spaces, having reference to

page_text: tbe more perfect gearing of the same on that part when the respective pitch
circles of each drum meet.
Secondly, in such construction and arrangement of the teeth and spaces on
the drums as will enable the teeth to fit more completely than hitherto into
the corresponding spaces, and thus more effectually to exhaust the air, and
likewise impede the return of the fluid which has once been raised.
Thirdly, in the gearing of the outer wheels on their respective pitch circles,
and in conformity with the requisito motion of the drums when such outer
wheels are used.
Fourthly, in the construction of the drum casing, whereby that pressure of
the water against the teeth which is antagonistic to the rotation of the drums
in raising and propelling (or forcing as it is often termed) is to the utmost
diminished, while certain other pressure of the fluid corresponding with the
rotary motion of the drums is as little as possible prevented.
Fifthly, in stopping the leakage, which is often considerable from the upper
parts of the drum casing.
Sixthly, in the side orifices for introducing the drums into the casing, so that
they can be extracted or changed without dismounting the end covers from
the drum casing.
Seventhly, this my improved apparatus may to a certain extent be made
self-acting and maintaining, and further it can be used as a motive power,
and may become available for several purposes.
Rotary pumps composed of two drums (or broad wheels) inside a casing,
having the teeth of cach drum to gear into the corresponding spaces between
the teeth of the opposite drum have been frequently tested and abandoned on
account partly of the friction and consequent wear of the teeth, and partly
because the rate of velocity at the tip (or extremity) of cach tooth is greater
than that at the root (or bottom) of cach space; and in consequence of this
variation in the respective velocities (a result produced by the outer circle
denoting the circumference of the tips of the teeth being greater than the
inner circle marking the roots or bottoms of the spaces) the fitting of the teeth
into the spaces has not hitherto been sufficiently exact to insure the efficient
action of the pump. Attempts have been made to overcome the wear upon
the teeth, chiefly by causing the rotary motion of the drums to bo com-
municated to them through the medium of wheels gearing into each other
outside the drum casing; but these efforts have not (till my present improve-
ments) proved successful, for the reason that the rate of velocity is (as just
explained) greater at the tips of the teeth than at their roots (the bottoms of
the corresponding spaces) into which they gear, and the velocity of the pitch

page_text: circle also differs both from that of the tips of the teeth and that of the
bottoms of the spaces, all which inconveniences operate just as much on the
outside wheels as on the drums (or inner wheels) themselves.
My improvements in the construction and arrangement of the teeth and
spaces are such that the teeth of one drum (as the pair revolves) shall bear
upon the spaces of the other drum on (or very near upon, as is hereafter
more fully described,) that part where the pitch circles of the two meet at tho
point E of the (dotted) line of centres F, G, Fig. 1, or in other words that
the two drums shall gear on (or very close upon the point of contact of their
pitch circles. With a view to the more perfect and uniform working of each
tooth into its corresponding space in the manner above described I prefer that
the teeth take a spiral direction froin end to end of the drum, and that for
small teeth and spaces the degree of spiral slope from one end to the other of
the drum be equal to the distance between the tip of one tooth and the tip of
the next on the same drum. For drums having ten teeth I prefer to lessen
the degree of spiral, for the reason that the quantity of inflated packing
(bereafter to be described in this Specification) would be very considerable
and indeed inconvenient at the ends of spaces so large as those in drums
having ten (and more so for seven) teeth, which would necessarily be widely
distant from their corresponding teeth and spaces at the other end from that
of contact, and for this reason I prefer to make my teeth nearly or quite
longitudinal for drums having only five teeth and spaces. All teeth and spaces
could however be constructed nearly or quite longitudinal upon the drum, or
may even be allowed to describe a curve or other arbitrary direction, pro-
vided the teeth and spaces of each drum (of the same pair) so perfectly
coincide that they gear correctly into each other. The two drums (of a pair)
may be of different dimensions, provided the teeth and spaces of the one
correspond in shape, size, and direction, and that they gear smoothly into those
of the other drum, and that the drum casing conform with the shape of the
pair; but I much prefer that the two drums be of equal dimensions. As tho
rate of velocity of the tip of each tooth must necessarily exceed that of
the root of each space, some amount of play between the teeth and their
opposite spaces may be expected, whence the escape of a portion of fluid
from the chamber B, Fig. 1, and its return to the chamber A might happen.
With a view more effectually to obstruct such communication I cover all (or
part) of the surface of each of the spaces (I prefer to do this from pitch
lino to pitch line of each space) and I fasten to the drums securely
and bermetrically the edges of the said covering, leaving, however, the re-
mainder thereof free from adhesion to the drum. Beneath tho said cover-

page_text: ing (which might be termed packing) I allow a small quantity of atmo-
spheric air to remain, without the possibility of its escape from between the
said covering and the drum (unless the covering be worn or torn), or I might
introduce gas, spirit, water, or other fluid, but I prefer in ordinary cases to
adopt air for this purpose. As the upper part of each tooth (when the drums
rotate) presses upon one more than another part of the space (or rather of the
covering aforesaid) into which it gears, the above-mentioned covering or
packing (being flexible) will yield on the spot so pressed, while the air con-
fined beneath it will cause the portion not indented to bulge or swell, by
which arrangement of packing I insure constant contact between each tooth
and space as they alternately gear into each other. That the tip of a tooth
gearing into a space may not grind or injure the coating I hollow out slightly
the spaces below the pitch, rather than diminish the teeth, in proportion to
the thickness of the inflated coating or packing. If, however, outside wheels
be not used to prevent the friction of the teeth, I prefer to construct my
spaces with more recess, so that the pitches may receive the brunt of
the pressure, while the contact of the tooth with the packing is an
indentation on a yielding substance; the tooth above the pitch might indeed
be lessened, but the fact of the space (not the packing) being recessed will
better answer the purpose. The packings of the spaces may be secured at or
near the pitches by metal (or other hard) bars or bands which would well
bear the brunt of the friction. Suction is through this contact of tooth with
packing more speedily and surely obtained, the passage of water between
tooth and space is checked and the action of the pump is consequently
improved. Since the pressure of a tooth upon the flexible covering of a space
not having a spiral direction, but one precisely longitudinal, would, as the
drums rotate be liable to force the confined air towards the edge (at or near
the pitch where I prefer that it be fastened to the drum), or in drums having
teeth and spaces in a spiral direction might force the confined air towards one
end of each space, and thus burst the covering, I sufficiently recess each
space or make one or more indentations or grooves in the drum (or both
recess and groove), which arrangement allows the confined air to pass freely
from that edge, towards which it is forced to those parts not pressed, and I
prefer that these grooves be more considerable towards the end than the
centres of the drums. A somewhat similar effect might be produced by
shortening the teeth, so that they should not press the covering quite to the
bottom of the spaces, but I prefer to use the recesses or grooves. When the
teeth and spaces are constructed with a spiral direction upon a pair of drums
the flexible covering of each space (as likewise that of each tooth when such

page_text: covering is adopted for the teeth) cannot have at one and the same instant a
pressure equal along the entire length thereof, because the contact (and con-
sequent pressure) commences at one end of each spiral space (and tooth) and
terminates at its other extremity. Thus a larger amount of flexible covering
will for spiral spaces be required towards the drum ends than in their centres;
an excavation or recess of suitable proportions will therefore be required in
the drum at each end of every space (or tooth) on that spot where the packing
would be jammed against the casing unless there were room allowed in the
drum to enable the flexible materials to fold or crumple up beneath the tooth
A
of the opposite drum and over the bottom of the space in its own drum.
flexible coating might be fitted in the end cover of the casing to palliate the
jamming at the space ends, or the spiral might be slightly altered for the
same purpose, but I decidedly prefer to use the first mode described rather than
have the recourse to either of these latter expedients. The teeth also may
be covered by an inflated flexible sheathing in a manner very similar to that
above described for the spaces, but the necessity for such covering on them is
less when the spaces are provided with it. If both teeth and spaces be so
covered I prefer that the flexible materials should be drawn somewhat closer
over the former (that is less inflated) than is done for the latter. Were
there any communication for the air beneath the covering of the teeth with
that of the spaces, such circumstance would not render the pump absolutely
useless, since the pressure of water on other parts would insure the reinflation
of the packing after its having been momentarily subject to the weight of
water in chamber B, Fig. 1, and the pressure at E. I prefer, however,
to construct my packings with no passage for the confined air beyond the
pitches of each space, though they might all be arranged so as to communicato
with a central chamber within the drum, and (through a longitudinal perfo-
ration in the spindle) to a fan or reservoir outside the drum casing; but this is
complicated and the pressure is difficult to regulate, therefore I prefer to use
packings having (as already described) no connection with any other packing
or with a reservoir. The several troughs or spaces may (and I prefer
that they should) have a (thin) sheet or leaf of metal (vulcanite or other
substance) so placed as to close a portion of (one or) both ends, whereby
the friction of the inflated packing against the drum casing can be
avoided, while at the same time leakage from the lower parts of the
spaces is stopped. To dispense with the necessity of shortening the
several teeth (endways) so as to allow them to fit into the spaces thus stopped,
I prefer to use one circular plate of metal (or other suitable substance) at
both extremities of each drum and to bring these plates from the spindles to

page_text: the pitches, causing the same to project beyond the drum itself, making at the
same time suitable recesses in the corresponding end covers of the drum
casing so as to enable these plates to fit into the end covers and to rotate with
the drum (the same of course for each drum); thus the teeth will above the
pitch touch lightly the drum casing just as well as if there had been no plates
projecting beyond the drum. The above plates recessed in the end covers
may be detached from the drum, acting somewhat like antifriction collars, or
they may extend short of the pitches or of the axles; but neither of these
modes will act so well or be so convenient for recessing in the end covers,
therefore I prefer that they be secured to the drum ends and reach from axles
to pitches. There might likewise be added an antifriction collar (or more
than one), but to allow space for this would augment the thickness of the
casing; when, however, the ends of chambers B and B', Fig. 1, are closed (as
will be described) and the plates covering those openings shall meet the others
closing the trough ends (which is the arrangement I find acts best), then
these additions closing chambers B and B' should (by preference) be of the
same thickness as the places on the drum ends (above described), as they will
also fit into recesses in the end covers.
The coating which confines the air in the packings can be made of any
flexible substance through which air cannot penetrate or which is impervious to
gas, spirit, water, or such other fluid as may be inserted between the drum
and the covering. I prefer to employ india-rubber fabrics, bladder, or fine
skin (single thickness or more) and to strengthen the same with (fine or
coarse) linen, or with silk, cloth, or other materials not likely to crack or tear
which I cause to adhere by solution of india-rubber or any other suitable
compound, though they may be used without adhesion the one to the other.
As already stated attempts have been made to avoid the hard friction of
one drum against the other by causing them to rotate through the action of
wheels outside the drum casing secured on the axles of the drums within,
which desideratum has not however been satisfactorily accomplished, because
the velocity of the tips of the teeth is superior to that of the roots, and each
tooth consequently requires a larger space while the drums rotate than it can
fill while they are stationary; hence the movement of the outside wheels (as
hitherto constructed) cannot (in regard to the teeth and spacos) exactly cor-
respond with that of the inside drums unless the teeth and spaces of the
former be in precise conformity with those of the latter. To obviate this
difficulty I construct my drums so that their respective pitch circles meet (or
very nearly so) at the point where they are intersected by the line of centres;
and I construct my teeth and spaces by preference with a spiral thread or

page_text: direction on the drums, though a curve or other arbitrary course given to the
teeth and spaces would not destroy the efficiency of the pump. The shape of
the teeth and spaces I prefer to be semicircular, though epicycloidal, hypo-
cycloidal, involute curves, or other arbitrary forms might be adopted; moreover,
semicircular teeth and spaces fit to each other better, and the action of the
tooth in the space (or packing within the space) is rather rolling than
frictional. As to the teeth and spaces of the outer wheels (when such are
employed outside the drum casing) they may be of any convenient shape or
size, and may be cut in the said outside wheels in any direction (straight,
curved, oblique, or other) provided the said outside wheels gear upon (or very
near to) the point where the line of centres intersects their respective pitch
circles, because that will correspond with the working of the drums within the
casing. These outside wheels may be on one or on each side of the casing,
that is, secured on one end of the axle of each drum of the pair, or on both
ends of the same axle, and if their teeth be in an oblique or spiral direction
each on the same axle should be obliqued from the drum or each towards it,
otherwise the drum would lean more against one end cover than against the
other. Those drums, however, which revolvo upon their axles through the
action of the outside wheels might, without the pump being rendered useless,
be prevented from grinding against each other with hard frictional contact at
their pitches (such as would entail speedy wear) because the communication
from chamber B to chamber A would (as already described) be impeded by
the inflated packing. And I wish it to be clearly understood that when I say
that the drums (and the same regards the outside wheels) should gear upon the
point where their line of centres intersects their pitches (or very near thereto)
I prefer that the contact and gearing be exactly on that spot; nevertheless, if
a slight deviation were to occur rotation could be obtained, though ever so
trifling a deviation from the proper point would be an imperfection entailing
greater play between tooth and space, which with careful workmanship need
not occur; and the better to insure the attainment of this object I construct
my outside wheels with short teeth running in a greater degree of spiral or
oblique direction than that already recommended for the teeth and spaces of
the drums.
I construct my drums and their casing of that relative size and shapo in
regard to each other that the former come as close as possible in contact with
the interior of their casing without scraping hard against it, and I prefer to
prolong their contact from the lower chamber A, Fig. 1, even quite to the
points a and a", or at the least that the tips of the teeth (if large) touch the
inner surface of the drum casing from d to a and d to a", though less length
B

page_text: of contact might suflice with small teeth, and I also make my end covers to
fit the casing against the drum ends S and S. While the drums rotate
rapidly that motion of spinning round on their axles has a tendency to
check (and even to prevent) by those drum ends the escape of fluid from B
to A unless the pressure from the outlet tube D be excessive. For the more
complete prevention of such passage, and the consequent loss of water, the
flat ends S and S of the drums may be coated with linen, india-rubber, cloth,
or other substance unless the plates from axle to pitch (already spoken of)
be used, and then the remainder of each tooth could be covered; and I prefer
that the materials used for this purpose should have a nap on them, as cloth
or velvet for instance. The end covers of the casing itself (on the parts not
recessed for the plates) might be coated in a similar manner (with or without
inflation), but I prefer that such coating, if used, be not inflated, and that
two fabricks, each having a nap on their respective surfaces, do not come in
closer contact than the tips of the naps because there would necessarily result
much wear from any greater friction. The axles or spindles can be set so
that the drums on them work horizontally, though the pump would act quite
well if the drums were with their axles placed in a perpendicular or other
position, the casing (with its inlet and outlet constructed in any convenient
situations) being of course shaped in conformity with the position of the
drums and the stand on which it is intended that it shall be fixed. The
drums of pumps used for raising and forcing would generally be them-
selves horizontal, and would be horizontally situated by the side of each
other. Ships' propellers would generally bave their drums in the horizontal
position, but (differing from the last-mentioned) these drums would be more
convenient the one above the other; their axles might, however, be perpen-
dicularly placed, the two drums working on the same level.
In constructing the main body P, P, P, P, Fig. 1, of my casing, I prolong
the segments of the outer circles C and C, which designate the circumferences
of the tips of the teeth, or, in other words, are the diameters of the drums
from tooth tip to tooth tip, and are parts of the inner surfaco of the main
body P, P, P, P, of the casing, and I continue them (the segments of C
and C) on each side P, P, of the said main body of casing (by preference)
to or even with small teeth beyond the point a on the one side and a" on
the other side, so as to enclose and touch the outer edges or tips of the drums
within instead of ceasing the contact at L and L. According to the old
mode of construction the pressure of water against the faces of the teeth
(as shown by the short straight featherless arrows c, c, c, is allowed to
act in an opposite direction (shown by the long curved arrows) to the

page_text: rotation of the drums S and S, consequently a greater amount of force is
required to overcome the resistance than would be necessary when that
opposition is diminished. By prolonging the contact of my drums with their
casing to (or beyond) the points a and a" I add to the old form of casing
the pieces L, R, a, and L, R, a", whereby the pressure from the weight of
the water in the discharge tubing D is prevented from affecting those teeth num-
bered 1, 2, and 3. If, however, I were to cause the segments of C and C to stop
short of a and a" I should leave the teeth of my drums just so much exposed
to the action of the water in chamber B; but while I thus materially
protect my drums from some adverse pressure I allow the maximum which
is possible of that favorable to their rotation (arrows b, b,) consequently a
lesser degree of force is required to rotate my drums. The segments of
circles C and C might indeed near the end covers be prolonged till they
actually meet above the drum ends S and S at each or either end of
the casing. When the teeth are constructed in a longitudinal direction,
and the segments C and C meet at the drum ends over the point of con-
tact E, the segments should gradually separate as they approach towards
the centre of the casing, where, in this instance, I by preference put
the exit orifice D, which gradual separation leaves a conduit for the flow
of the water from the trough ends towards the exit orifice D. If, however,
the teeth be in a spiral direction the junction of the segments of C and C
may for some distance from one end be continued even till beyond the middle
part of the pair of drums, so that from that end where commenced the union
of the segments to the spot where they separate, each drum of the pair would
be under an arched casing or a segment of a tube. The junction of the
segments C and C (or, in other words, the pair of arches thereby formed) must
in this instance be at that end of the pair of drums where commences the
contact between their respective teeth and spaces, because the water is by
this contact (of teeth with spaces) forced from that extremity of the troughs
towards the other end of the pair of drums where the contact between the
teeth and spaces terminates, and where of course the water requires an
egress. That end of the pair of drums where commences the contact of spiral
teeth and spaces is thus completely covered and protected, and the only part
which is open to the chamber B is that where terminates the contact of their
teeth and spaces. In all instances I prefer that the ends of the chambers B,
and B', and the trough ends should be securely closed, by which improved
arrangement leakage between the flanges or upper joints in the casing
(elsewhere mentioned in this Specification) is stopped.
The manner which (by preference) I employ to close the ends of chambers

page_text: Band B', is to solder or otherwise securely fix at each end a sheet or leaf (by
preference made of metal), and I make these leaves meet the circular plates
(already mentioned) which close the ends of the troughs or spaces of the
drums. Contact being thus effected between the above-mentioned leaves and
the plates no leakage worth consideration can occur from that part, and
consequently none can penetrate through the packing of the flanges; tho
pieces or leaves closing the ends of chambers B and B', projecting as they
do beyond the main body of the casing ought to fit into recesses in the end
covers as already recommended for the plates which shut the lower parts of
the spaces, by which arrangement the teeth need not be diminished to accom-
modate themselves to these leaves, neither need segments of circles be added
to the interior of the end covers to accommodate themselves to diminished
teeth. If, however, the said leaves be fastened upon (or if constructed with
the casing P, P, P, P, so as to be flush with the flat ends thereof), a dimi-
nution in the (longitudinal) size of the teeth becomes necessary, to which
alteration the end covers must be made to match, which inconvenience it is
desirable to avoid. When the ends of the above-mentioned chambers and
spaces are carefully closed by leaves and plates (which is the mode I follow and
recommend), the importance of constructing in one piece the main body with
one or both the end covers, or of soldering them together no longer exists.
When casings are constructed so that segments C and C meet at the junction
of the circles of the tips (whether fastened upon or constructed with the
casing) quite closing B', and nearly so B, a comparatively small leaf (or
leaves) should close the aperture between those arches and the plates, which
mode offers the advantage of being able to extract and refit a drum (or both)
from the side instead of from the bottom, and in this case the upper portion can
be allowed to be flush with the main body, while that part only which comes
in contact with the teeth stands beyond the main body P, P, and is recessed
in the end covers. The lower chamber A (of ingress) might be closed in
a manner similar to B and B', but as the pressure if of water does not in the
like decree affect that chamber there is no object to be attained worthy of
the extra trouble.
When an apparatus is constructed which may be liable to sustain so great
a weight of water as to endanger the stability of the prolongations L, R, a,
and L, R, a", Fig. 1, the casing should be strengthened by an augmentation
of metal or other suitable materials, either partially or for the entire length
of the pair of drums.
Without dismounting an end cover the drums (or either of them) can be
taken out and refitted by constructing in each end casing a circular orifice the

page_text: circumference of a drum, through which a drum can be inserted into the
casing, the aperture being afterwards closed by a similarly sized circular plate
screwed into the end cover, or otherwise securely fitted. Through the opposite
end cover the other drum can be removed by a similar arrangement or (in
certain cases when only one side can conveniently be reached), both orifices
can be made on the same side, though that requires extreme nicety of work-
manship because one circle would bite into the other. As the raising of
water by this apparatus when it is placed above the water is effected by first
exhausting the air from the chamber A, Fig. 1, and the tubing below the
inlet orifice O, and then sucking up the water, it is evident that the operation
must be performed quicker if water be already in the casing. With this
view a valve (or more than one) may be fixed in the casing (by preference at
the bottom of chamber A, and immediately above the inlet O), or it could be
put in the tubing (or in both casing and tubing) to retain the water once
raised, and thus secure a more speedy flow. The raising or lifting of water
beyond the outlet orifico D partakes rather of the nature of forcing or
propelling; the placing of this apparatus above the water is however a mere
matter of convenience as it can act equally well when partly or wholly
immersed. Moreover it can draw in water at the top, and force it through
an orifice (or orifices) at the bottom, or on either or both sides just as well
as through the upper part.
When this apparatus is applied as a means for propelling vessels through
the water, the very close fitting of the teeth of the drums into their corre-
sponding spaces is not of such importance as it would be in raising water by
suction, inasmuch as the apparatus is generally below the water line of the
vessel, and therefore does not commence to operate by a vacuum and suction,
but by at once driving or propelling. It is, however, very desirable that all
parts match and fit well, and that a reflux between the teeth and spaces of the
pair of drums (or through any other parts) be not allowed, because the power
of the apparatus as a propeller for ships would be diminished in the same
proportion as any quantity of water once brought into the exit or upper
chamber B, Fig. 1, were permitted to return to A, instead of issuing in full
volume at the nozzle or other orifice attached to tubing D.
Since the exact quantity of water or other fluid which each space or trough
on the pair of drums conveys into the upper or exit chamber can be easily
ascertained the amount raised on each revolution of the drums can be cal-
culated and registered by fixing upon an axle a suitable index. By diminishing
to the utmost the pressure of the water acting in the sense contrary to the
rotation of the drums (arrows c, c, c, Fig. 1, as already explained) and on

page_text: the other hand by retaining all that is possible of the pressure favorable to
the said rotation (arrows b, b,) little physical strength is required to make
the drums of my apparatus revolve on their axles, and by that means deposit
in the upper chamber successive troughs filled with water. By obstructing
the reflux or escape of water between the teeth and spaces, and preventing
leakage by the end covers, it is obvious that whatever fluid may have been
emptied into the upper chamber by the troughs must, as more continues to
be brought in by the successive revolutions of the drums, find an outlet
through the sole orifice D, though tho height to the top of the tubing be con-
siderable, and thus issuing from the top of a high tube (or through a nozzle).
The water thus raised may be so directed as to flow upon a wheel (or wheels),
or into a cistern, and thence on a wheel (or wheels), or upon floats at the
top (side or bottom) of a wheel, or into recipients attached to a wheel, must
cause the same to revolve by the force (or weight) of the water acting upon
it. Any wheel being thus caused to revolve can be made to act (I prefer to
use a pinion) upon the spindle of one drum (or spindles of each) or on one
or both of the outside wheels, with or without connecting wheels (or by
a chain, strap, or other connection), and thus it can turn or help to turn the
axles of the drums, whereby the apparatus becomes to a certain extent self-
acting and self-maintaining, that is to say, it so becomes after it has been
properly prepared or motion has been communicated to it in any suitable
manner. The way which I (by preference) use and which I recommend is
by first filling with water the tubing, upper cistern, and a portion of the
recipients (the down inclination of the wheel) ready for the action to con-
mence so soon as a bolt (or other stay) shall be withdrawn for the purpose of
allowing the said wheel (its cups on the downward side being already filled)
to revolve by the weight of its filled cups, and the subsequent flow of water
into its empty cups, as each trough, can, or other recipient alternately reaches
the top (or other suitable part) of the wheel once in motion, the said cups or
cans (filled) being each in turn emptied as one after the other in consecutive
order arrives at the bottom of the wheel; thus it is manifest that the cups
which descend are full and heavy, while those which mount with the ascending
part of the wheel are empty and light, the wheel (or wheels) being, if circum-
stances and situation permit, of that diameter which is sufficient to impart
a force superior to the loss of the various portions of the apparatus from
friction. The volocity in the rotation of this large wheel may be easily
regulated by augmenting or diminishing the orifice for the flow of water upon
it, and the upper cistern ought to be furnished with a waste pipe to convey
the overflow into the lower cistern, whence the water is drawn and forced by

page_text: the revolving drums of the apparatus. It is true that the greater the
diameter (and power) of the large wheel (or wheels) in like proportion must
be the height of the egress tube D, and consequently the stronger must be
the pressure of the water on the faces of the teeth cut in the drums, but in a
like degree (dependant of course on that pressure) do these teeth become
influenced by the downward and favorable effect (arrows b, b,) whereby the
rotation of the drums is to the same extent facilitated; and it is self-evident that
the arrangement which, after deducting the drawback from friction, enables
the water from the discharge tube D of the apparatus to turn the axles and
revolve the drums thereof, is equally applicable as a power to move machinery,
which is not here further described as it forms a separate application.
When my improved apparatus is employed to pump water from mines or
for any other purpose which requires fluid to be lifted or forced to a great
height, a succession of pumps can be arranged at stages rather than allow so
heavy a weight of tubing to bear upon one and the same drum casing and
such a large column of water to press upon the interior of chamber B, Fig. 1,
so as to require extreme strength with a proportionate thickness of metal for
that part of the casing; for though the full effect of the weight of water
might be mitigated by one or more valves above the chamber B, they (quito
suitable for certain things) would be inconvenient contrivances for such uses
as the present, and might often get out of order. Each stage (when tho
pumping is to be done by stages) should have its own apparatus raising from
a lower and forcing to a higher reservoir till the top of the mine (or other
place) be reached and the water flow out. Each apparatus in the series of
successive stages could be so arranged as to be to a certain extent self-acting
and maintaining (as already described) or the requisite force (or any portion
thereof) could be communicated to the whole series collectively, or to cach
stage separately by hand, horse, or other power above or below ground; but
neither in this nor under any other circumstance is it essential that the drums
of my apparatus be placed above the water, since they could rotate and
thereby draw and force fluid equally well were the bottom of the casing were
considerably above, or if flush with the surface of the water, or if wholly or
partially immersed.
My improved apparatus may be used to pump air and force it through
tubes for the purpose of ventilation in mines or elsewhere, or through a
nozzle as a bellows or fan would operate for a blast furnace or the like uses.
When so employed the entire apparatus can be constructed of very light
materials, and the drums as well as the interior of the casing had better bo
covered with cloth or velvet having the nap outwards. When used as a fan

page_text: I decidedly prefer (though the apparatus is light) to adopt outside wheels,
(for which I prefer metal,) they being the more necessary [on account of
the slightness with which the inside wheels or drums would (probably) bo
constructed.
Among the various useful applications to which this my improved apparatus
is suitable, not the least important is as a fire engine. On a large scale it
can, with the employment of comparatively little physical force, throw an
uninterrupted stream of water to a great height and distance, or on a small
scale it can be carried upstairs or through narrow passages. As an engine to
water gardens, lawns, and even fields, it can be fitted on a large or small
scale, and is extremely convenient when mounted on a species of wheel barrow
very similar to that used by the itinerant knife-grinder, which is rotated by a
wheel and treadle. It must however be observed that suction can only be
obtained for a limited distance, and that the hose should always be composed
of materials not liable to collapse on the creation of a vacuum, otherwise it is
necessary for fire, garden, and the like engines to have an apparatus placed
at or near the source of water, so as to force the same along the hose to the
delivery engine, which thus supplied would play as required and directed, or a
nozzle or rose could throw water though with less power without the aid of
a second apparatus. If a hose is dragged along the ground for a considerable
distance it can at intervals be supported by pairs of (little) wheels. As a
ship's pump it is extremely efficient and can act on deck or in any part of the
vessel, even submerged in the hold, and in an emergency at sea it can be
adopted as a fire engine.
And in order that my Invention may be the more fully understood I proceed
to describe the Drawing hereunto annexed.
DESCRIPTION OF THE DRAWING.
Figure 1 shews a vertical section of the main body of the casing with its
drums. The dotted line outside of the casing shews where would come the
flange when the parts are held together by flanges. A is the lower chamber,
wherein the water drawn by suction through the inlet orifice accumulates, and
whence it is carried by the spaces into the upper chamber B. The chambers
A, B, and B' might be termed one chamber, inasmuch as they are parts of
the interior of the casing; but with a view to make this description more plain
I have distinguished them from each other. B is the upper chamber of the
casing, into which the water is carried by the spaces; B' is the higher portion
of chamber B; C and C are the segments of the circles of the circumference
of the tips of the teeth of the drums, making also the interior surface of the

page_text: main body of the casing. D is the outlet orifice; E is the point of contact
of the pitch circles of the drums; F and G are the axles or spindles of
the drums; II and H are the teeth of the drums above the pitch; K, K,
are the spaces below the pitch L; R mark the places (dotted line)
where commence the prolongations for the contact of teeth with their
casing; M and M are pieces inserted in the casing when drums are let in
from the bottom; N, N, is the plate closing the bottom, when drums are let
in from the bottom; O is the lower or inlet orifice; P, P, P, P, is the main
body of the casing; Q, Q, is the stand; S and S are the drums; T, T, are
the points to which the pressure of water in chamber B would reach if there
were no prolongations beyond the dotted line L, R; U and U are the pitch
circles; a and a" are the extremities of the prolongation; a', extremity of a
less prolongation from L, R; b and 6 shew the direction of the pressure of
water favorable to the rotation of the drums; c, c, c, shew the pressure in the
sense unfavorable to the rotary movement; d and & are the extremities of
the pieces M and M, whence to a and a" contact of the teeth with the segments
of C ought (especially with large teeth) to be perfect unless the prolongations
at L, R, be shortened; x and x are arrows indicating the direction of the
rotation in drawing and forcing. The arrows unlettered shew the direction of
the flow of water.
Figure 2 shews a vertical section of the drums and main body of the casing
with flanges, into which casing drums cannot be inserted from the bottom.
U and U which indicate the pitches, also shews the edge of the plates which
close the trough ends (dotted) below the pitches; f shews the leaf which
closes the end of chambers B and B' to prevent leakage, and reaches to the
plates U and U; S and S are the drum ends covered by the plate to the
pitches U and U.
Figure 3 shows an end cover Y, Y, closing the end of casing with outside
wheels (dotted) gearing into each other; D, exit orifice; C, inlet orifice;
9, 9, stand for pump; 9, 9, (dotted) outside wheels on the axles F and G;
,, stuffing boxes.
Figure 4 shews another shape of casing, the drums being the one above
the other with inlet orifice suited for a fan; exit orifice D with nozzle; inlet
orifice O; stand 9, 9; 9 and 9 outside wheels.
Figure 5 shews a space k with flexible packing (dotted) pressed at e.
Figure 6 shews tooth H and space K with flexible packing not pressed.
Having thus described the nature and object of my Invention, and the
method of carrying it into practice, I would have it understood that I do not
confine myself to the mere verbatim details herein shewn and described, so

page_text: long as the peculiar character of my Invention is retained, but what I claim
is,―
Firstly, the inflated covering arranged as a packing to impede tho escape
of fluid between the teeth and spaces.
Secondly, the extension of the interior of the drum casing bordering the
tips of the teeth, and thereby shielding the said teeth from a portion of the
pressure from the fluid in the upper part of the casing, designated in this
Specification the chambers B and B'.
Thirdly, the stopping of the ends of the upper part of the casing designated
a chamber B and B', to prevent the escape of fluid from those ends.
Fourthly, the closing of the lower parts of the spaces or troughs to shut off
that way the escape of fluid, and also prevent the jamming of the flexiblo
coating against the end covers.
Fifthly, the combination of this pump with a wheel or wheels, turned
by fluid raised or propelled by the apparatus, and so connected therewith
as to become, to the extent described in this Specification, self-acting and
maintaining.
In witness whereof, I, the said Hugh Forbes, have hereunto set my
hand and seal, this Ninth day of April, in the year of our Lord
One thousand eight hundred and sixty-seven.
HUGH FORBES. (...)