IMPROVEMENTS IN AND RELATING TO SCREW PUMPS AND HYDRAULIC MOTORS
Year: 1880

page_text: LETTERS PATENT to William Anderson, of 3, Whitehall Place, and Wilfred
Airy, of 7, Queen Anne's Gate, both in the City of Westminster, for an
Invention of "IMPROVEMENTS IN AND RELATING TO SCREW PUMPS AND
HYDRAULIC MOTORS."
PROVISIONAL SPECIFICATION left by the said William Anderson and
Wilfred Airy at the Office of the Commissioners of Patents on the 10th July
1880.
$6
WILLIAM ANDERSON, of 3, Whitehall Place, and WILFRED AIRY, of 7, Queen
Anne's Gate, both in the City of Westminster. IMPROVEMENTS IN AND RELATING
TO SCREW PUMPS AND HYDRAULIC MOTORS."
This Invention has for its object improvements in and relating to screw pumps
and hydraulic motors.
The screw which we employ as a screw pump, and also in some cases as an
hydraulic motor, consists of three parts, the core, the threads, and the envelope,
and these together enclose passages open only at the ends and passing spirally
around the core. This screw being mounted in an inclined position and caused to
rotate takes in water at the lower ends of the passages and delivers it at the upper
end. Or when employed as a motor, water allowed to enter the passages at their
upper ends flowing down through them to the lower level causes the screw to
rotate.
The core consists of a rivetted tube having cast iron ends provided with pivots
or stud axes which are received into top and bottom bearings.
The thread of the screw is capable of development, that is to say, when separate
from the core and envelope it can be spread out flat; indeed its form is that taken
by an annulus of sheet metal cut through radially and then wound upon the core,
so that the inner edge of the annulus may meet the core along a spiral line, the
annulus itself becoming a screw thread upon the core and making with it obtuse
and acute angles. In the working position of the screw the acute angle is
downwards.

page_text: In constructing this screw we employ a cast iron block having a surface made
to the form of one of the threads, and with angles at the sides corresponding to the
angles at which the thread meets the core on the one side and the envelope on the
other.
The sheet metal to form the threads having been cut to the proper shape is
heated, then laid out on the block, and so is set to the required spiral shape. The
same block also serves to shape the angle irons by which the thread is connected
with the envelope and with the corc. The angle irons are heated, laid out upon
the block, and made to conform to the angles at its sides. The parts being thus
set to form, the rivetting up is done without difficulty.
For the purpose of imparting motion to the screw (or transmitting motion
from it if it be used as a motor) a ring of teeth is fixed around the envelope near
the upper end, and a pinion gears with the ring on one side, and so that the
pressure upon the teeth of the ring is in an upward direction tending to relieve tho
-weight upon the upper bearing. The upper end of the screw when at work is
partly immersed in the water-at-the-higher level, and a watertight joint is formed
around it by means of a valve like flap of leather closing against a flange or ring
fixed upon the exterior of the envelope. In this way the water is stopped back
whilst the screw is free to rotate. The flap is provided with a metallic bearing
surface. A large flap valve is also provided to prevent a downward flow of the
water when the screws are not at work.
The lower bearing or foot step of the screw we form with trunnions carried in
bearings in which they can rock, so that the footstep is able to accommodate itself
to the position of the axis of the screw. The bottom of the footstep consists of a
plate attached to the trunnion or body piece by bolts, which also serve as a means
for adjustment and to compensate for wear. The bottom plate has blocks of
-lignum vitæ let into its face, and on these blocks the end of the axis abuts. The
trunnion part or body of the footstep_is_bored out to a size to receive live rollers
between itself and the pivot or stud axis of the screw. As many of these rollers
are employed as the annular space around the axis will contain, but they are not
all of the same size. Each alternate roller is made slightly smaller in diameter, and
the axis does not bear upon theso smaller rollers which serve to keep the larger
rollers properly spaced, whilst at the same time all rubbing friction is avoided.
The upper bearing of the screw we form in a similar manner but without the
arrangement to take the end on thrust.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Anderson and Wilfred Airy in the Great Seal Patent Offico
on the 10th January 1881.
WILLIAM ANDERSON, of 3, Whitehall Place, and WILFRED AIRY, of 7, Queen
Anne's Gate, both in the City of Westminster. "IMPROVEMENTS IN AND RELATING
TO SCREW PUMPS AND HYDRAULIC MOTORS."
This Invention has for its object improvements in and relating to screw pumps
and hydraulic motors.
The screw which we employ as a scrow pump, and also in some cases as an
hydraulic motor, consists of three parts, the core, the threads, and the envelope,
and these together encloso passages open only at the ends and passing spirally
around the core. This screw being mounted in an inclined position and caused to
rotate, takes in water at the lower ends of the passages and delivers it at the
upper end. Or when employed as a motor, water allowed to enter the passages at
their upper ends flowing down through them to the lower level causes the screw
to rotate.
The core consists of a rivetted tube having cast iron ends provided with pivots
or stud axes which are received into top and bottom bearings.
The thread of the screw is capable of development, that is to say, when soparate
from the core and envelope it can be spread out flat; indeed its form is that taken
by an annulus of sheet metal cut through radially and then wound upon the core,
so that the inner edge of the annulus may meet the core along a spiral lino, the
annulus itself becoming a screw thread upon the core and making with it obtuse
and acute angles. In the working position of the screw the acute angle is
downwards.
In constructing this screw we employ a cast iron block having a surface made
to the form of one of the threads, and with angles at the sides corresponding to
the angles at which the thread meets the core on the one side and the envelope on
the other.
The sheet metal to form the threads having been cut to the proper shape is
heated, then laid out on the block, and so is set to the required spiral shape. The
same block also sorves to shape the angle irons by which the thread is connected
with the envelope and with the core. The angle irons are heated, laid out upon
the block, and made to conform to the angles at its sides. The parts being thus
set to form, the rivetting up is done without difficulty.
For the purpose of imparting motion to the screw (or transmitting motion from
.it if it be used as a motor) a ring of teeth is fixed around the envelope near the
upper end, and a pinion gears with the ring on one side, and so that pressure upon
the teeth of the ring is in an upward direction tending to relieve the weight upon
the upper bearing. The upper end of the screw when at work is partly immersed
in the water at the higher level, and a water tight joint is formed around it by
means of a valve like flap of leather closing against a flange or ring fixed upon tho
exterior of the envelope. In this way the water is stopped back whilst the screw
is free to rotate. The flap is provided with a metallic bearing surface. A large
flap valve is also provided to prevent a downward flow of the water when the
screws are not at work.
The lower bearing or foot step of the screw we form with trunnions carried in
bearings in which they can rock, so that the footstep is able to accommodate itself
to the position of the axis of the screw. The bottoin of the footstep consists of a
plate attached to the trunnion or body piece by bolts, which also serve as a means
for adjustment and to compensate for wear. The bottom plato has blocks of
lignum vitæ let into its face, and on these blocks the end of the axis abuts. The
trunnion part or body of the footstep is bored out to a size to receive live rollers

page_text: between itself and the pivot or stud axis of the screw. As many of these rollers
are employed as the anuular space around the axis will contain, but they are not
all of the same size. Each alternate roller is made slightly sinaller in diameter,
and the axis does not bear upon these smaller rollers, which serve to keep the
larger rollers properly spaced," whilst at the same time all rubbing friction is
avoided. The upper bearing of the screw we form in a similar manner, but
without the arrangement to take the end on thrust.
In order that our said Invention may be most fully understood and readily
carried into effect, we will proceed to describe the Drawings hereunto annexed.
DESCRIPTION of the DrawINGS.
Figure 1 is an clevation, and Figure 2 is a plan of a screw pump constructed in
accordance with our Invention; and-the-same-is applicable, with but very slight
modification, as an hydraulic motor; Figure 3 is a vertical section of a part of
the screw.
.
a, a, is the core, and a¹, a¹, are pieces by which the core is closed at the ends;
upon them the pivots or axes of the screw are formed; b is the thread of the
screw, and c is the envelope. Figure 4 shows the developement of the thread b, or
the ring or annulus which it would form if laid out Hat; Figure 5 is a vertical
section of the cast iron anvil block which we employ in bending the parts to the
form they have in the screw. It is convenient that this block should correspond
to one thread of the screw through an angle of about 180 degrees. The plates to
form the screw thread having been cut to the proper shape (namely, to that of a
...portion of the annulus, shown at Figure 4), they are heated in a furnace, laid upon
the face of the anvil block, and made to conform-to-it. Similarly the angle irons,
in convenient lengths, are heated, and according as they are to connect with the
core or with the skin, they are laid either into the inner angle or over the outer
angle of the anvil block, and by hammering they are made to conform. The
pieces being thus properly shaped, rivetting them together presents no difficulty.
Upon the envelope of the screw a toothed ring a is fixed, and a pinion d upon
an axis e gears with it on that side, which, when the screw is worked as a pump,
is the ascending side. There is considerable advantage in placing the pinion in
this position, as the weight upon the upper bearing of the screw is thus relieved.
Where but one screw is in use this axis e may be the driving or the driven shaft,
but where there are several screws as will more commonly be the case, the axis c
carries a bevilled wheel el gearing with a corresponding pinion upon an horizontal
shaft to which the driving power is applied if the screws bo for pumping. Or
if the screws be employed as motors, this shaft f conveys the power to the machines
to which motion is required to be given.
Thero is also at all a ring fixed upon the exterior of the envelope of the screw,
and against this the valve like flap g rests so as to make a water tight joint. A
section of these parts in detail and to a larger scalo is reprosented at Figure 6; tho
ring is of wood faced with metal, and the flap is of leather with a strip of metal
attached at the back. The flap extends beneath the ring a, and rises on either
side to above the water level at the upper end of the screw; h is a flap valve
which closes to prevent the return of the water when the screws cease to be driven;
this valve when the screw is intended to be used as a motor is replaced by a sluice,
which can be opened and closed by a screw or other convenient mechanism.
Figures 7, 8, and 9 show to a larger scale and in detail the footstep for the
screw, marked i in Figures 1 and 2; Figure 7 is a side elevation; Figure 8 is a
back clevation; and Figure 9 is a plan partly in section. In Figures 8 and 9
the movable part of the footstep is shown as laid horizontally; k, k, is the part of
the footstep which is fixed; it is bolted in its proper position upon the supporting
girder. The part / has bearings formed in it on either side to receive the trunnions
m², m', of the moveable or rocking part m of the footstep. The part m is a
cylinder with an internal flange at the lower end, and it is bored out to a size to

page_text: receive the lower pivot of the screw together with the hard steel rollers o around
it. Alternately with these rollers there are other rollers o¹, o', very slightly
smaller. The rollers aro as nearly as possible in contact all around the pivot of
the screw. The lower end of the pivot is faced with brass and rests upon a plate p,
into which hard wood blocks are insorted. The plate p has a globular projection
at the back which is received into a corresponding cavity in a bottom plato q
which is secured to the cylinder m by bolts r.
Figure 10 is a side elevation of the similar bearing for the upper pivot of the
scrow.
Having thus described the nature of our said Invention and the manner of
performing the same, we would have it understood that we claim,―
First. The general arrangement and construction of screw or spiral pumps and
hydraulic motors, substantially as described.
Second. The method of constructing such screw or spiral pumps and hydraulic
motors by setting the parts to the requisite shapo upon a corresponding screw
form anvil block, substantially as described.
Third. The combination with such screw, or spiral pumps, or hydraulic motors,
for transmitting motion to or from them of a ring of teeth fixed upon the envelope
and a pinion in gear therewith, and so arranged that the pressure upon the teeth
of the ring is in an upward direction, substantially as described.
Fourth. The combination with such screw or spiral pumps and hydraulic motors
of a valvo like flap closing against a flange or ring fixed upon the exterior of the
envelope and forming a watertight joint, substantially as described.
Fifth. The combination with screw or spiral pumps and hydraulic motors of
trunnion rollor bearings, substantially as described.
In witness whereof, 1, the said William Anderson, have hereunto set my hand
and seal, this Seventh day of January, in the year of our Lord One
thousand eight hundred and eighty one.
W. ANDERSON. (LS.)