IMPROVEMENTS IN ROTARY PUMPS AND BLOWERS
Year: 1882

page_text: LETTERS PATENT to Martin Benson of N° 52 Chancery Lane London.-for
an Invention of IMPROVEMENTS IN ROTARY PUMPS AND BLOWERS Com-
municated to him from abroad by Francis Marion Roots of Connersville
Fayette County State of Indiana United States of North America.
PROVISIONAL SPECIFICATION left by the said Martin Benson at the Office
of the Commissioners of Patents on the 27th September 1882.
:
MARTIN BENSON of N° 52 Chancery Lane London. "IMPROVEMENTS IN ROTARY
PUMPS AND BLOWERS". A Communication to me from Abroad by Francis Marion
Roots of Connersville Fayette County State of Indiana United States of North
America.
My Invention relates to that class of rotary pumps in which two or more
Rotating abutments or pistons co-act together and with the shell in which they are
incased force a current of water or other fluid in one direction without permitting
back ward escapement of same under pressure, and is supplemental to iny Patent
for Improvements in Rotary Blowers and Pumps dated September 27th 1881
N° 4158.
The object of my present improvement is to produce pistons capable of
sustaining a heavy pressure with the least possible friction between the abutting
parts and to insure perfect contact between the abutments during their entire
revolution. It also consists in certain novel features of construction by which the
effectiveness of the machine is increased, and its interior working parts protected
from sediment, or heavy foreign substances.
In Letters Patent N° 4158 granted to me September 27th 1881 for Rotary
Blowers I describe a method for producing pistons which insures perfect contact
between then during their entire revolutions. The centres from which the arcs and
contact points are described are in an inscribed circle of about 11th less diameter
than the pitch circle, Pistons so constructed answer every purpose for a Blower
or other Engine in which the required pressure is usually about one to two pounds
per square inch, and never exceeds five pounds, but in pumps to be used
for fire purposes the pressure ranges from 100 to 150 pounds per square inch.

page_text: :
It is therefore necessary in this class of machines, that the size of the shafts
be increased and that the thickness of the metal around the shaft should not
be less in any part than one half the diameter of the shaft. To obtain these
results the abutments must necessarily be contracted in the direction of their
major axis and correspondingly widened in the direction of their minor axis.
The method described in said Patent N° 415881 will not produce such pistons,
because, the describing centres are too far from the axis of rotation. When
the centres from which the abutting surfaces are described are brought out
near to the axis, as they must be, to produce these heavier pistons, I have found
that the abutments will not clear each other, when the convex and concave arcs
meet in curves which are arcs of equal circles, but that in order to keep up
perfect contact with the least possible friction the convex arcs must be compound
curves and must meet the concave contact surfaces in an arc of a smaller circle as
hereinafter described I have also discovered a system for obtaining the centres
from, and the radius by which the smaller ares are described so that by my present
invention I am enabled to construct pistons of any required strength as will be
fully understood from the following description.―
-
Fig. 1. is a diagram illustrating my method, or system for obtaining the points
from, and the radii by which all the contact surfaces of my abutments are
described.
The abutment shafts D, D, are placed the requisite distance apart, depending
upon the size of the machine to be constructed. Two equal circles are described
around the shaft centres, by a radius, equal to one half the distance between said
centres, these pitch circles are divided by sectors into eight equal parts one of
these dividing lines passes when extended through both shaft centres marked
and the diagonal lines: z, z, Within the pitch circle and from its centre I describe
a smaller circle which I term the Inscribed circle, (about 1/6th less in diameter than
the pitch circle) The difference between the diameter of this circle and the pitch
circle (within limits hereinafter mentioned) determines the strength of the
abutments, the smaller the inscribed circle the heavier or thicker will be the
abutments through the waist or minor axis and vice versa. The points from which
the outer convex curves, and inner concave contact surfaces are described I obtain by
taking the difference between the diameters of the inscribed and pitch circles, and
then with one point of a divider in the point i where the line x cuts the inscribed
circle I step off this distance on the inscribed circle upon each side of line x
and obtain the point 2. From these points as centres the opposite convex arcs of
the abutments are described by a radius extending from said point ** across
line x to the point where the diagonal lines 2 cut the pitch circle. From these
points as centres the convex arcs and concave contact surfaces are described by the
same radius as clearly appears from an examination of the diagram.
It should be understood that the inscribed circle must not be so small as to throw
the point across the lines z, z, As before stated the convex curves must meet
the concave contact surfaces in arcs of smaller circles, or in other words the points
formed by the meeting of the convex and concave curves of equal circles must be
dressed off to arcs of smaller circles.
The centre and radius of the smaller arcs, I obtain by taking 2/3rd of the
difference between the diameters of the pitch and inscribed circles as the radius and
with one point of the dividers on point where the concave curve or point of contact
is cut by the inscribed circle I step off on the inscribed circle with the other point
of the divider this distance which gives ³ with this point as a centre I connect point i*
with the convex surface of the piston. This gives the exact shape the curved surfaces
of the pistons must have to move without friction and yet keep up perfect contact.
The center in the waist of the abutments or bottom of recess is described by a radius r
from a point in the line x, No arbitrary rule for describing this curve however is
necessary, it is only essential that it be cut back far enough for the free passage of
the end of the pistons, The ends of the pistons are the same as I have shown and
described in my patent N° 41581 and the method of dressing the pistons is

page_text: substantially the same as described in said patent with this addition the arc of
the smaller circle herein shown I find is more conveniently dressed off to the
template by a tool of suitable shape as described in my former patent for dressing
the concave surfaces than by centreing the piston at point *.
Pistons constructed with their convex arcs composed of a compound curve
described from points 12 and 25 make a perfect machine, as the pressure forward is
constant, without any backward escapement of the fluid, But I do not limit myself
to the exact curve described for the smaller arcs, as these are in contact with the
opposite abutments but a very short time during each revolution, Should perfect
contact not be kept up during this short time it is evident that the backward escape
would be so small as not to materially affect the usefulness of the machine nor do I
limit myself to the exact location of the point 2 as these may be slightly varied and
still produce a more effective machine than any other now known:
The other working portions of the pump are constructed essentially similar to that
described in my patent N° 415881 excepting the abutment or piston shaft are
packed where they pass through the heads or ends of the case and a receiving
chamber is made separately or in the bed plate over which the piston or abutment
case is attached and also the suction pipe. The abutment shaft revolves in bearings
attached to the ends of the casing and the shafts are provided with gear wheels at
each end of equal diameter for transmitting the power from one shaft to the other
in small pumps and to keep the abutments in proper revolving position one with
the other, The pump may be worked through the medium of belts over pullies
attached to each abutment shaft and at opposite ends of the machine or they may
be worked by applying Engine power direct or through the medium of gearing to
the end of one or both abutment shafts and arranged so that their cranks will be
at right angles or any other known means of applying power may be employed to
wortk the machine.
The abutments or pistons are usually made of cast iron for blowing purposes, but
can be made of sheet metal or steel by being shaped or stamped out in a cold or
heated state to the proper form in suitable dies or forming pieces. When the
abutments are thus made of sheet metal or steel it will be better to make them in
half sections or pieces and bolt and rivet them together at suitable points. The
piston shafts are provided with arms or centre pieces for attaching the sheet metal
abutments to them in any known convenient manner.
In some cases the packing glands are used to form bearings for the pistons or
abutment shafts to work in, provision is made to prevent dirty water from the
pump getting between the shaft and bearing portion of the gland this is done by
forming a groove on the inside of the gland near its inner end and a similar groove
on the outside of the gland opposite the one on the inside holes are made through
the gland opposite the grooves and thereby put the inside and outside groove in the
gland in communication and the groove on the outside of the gland is put in
communication with an opening made through the side of the packing chamber.
With the parts thus provided with grooves and openings it prevents any dirty
water that may come from the pump through the packing from getting between the
shaft and bearing portion of the packing gland by being drawn off from the gland
through the grooves and openings and thereby prevent cutting or injury to the
shaft where it works in the gland with any foreign matter that may be in the
water:
The machine may be used as a hydraulic engine, for this purpose water pressure
is made to revolve the pistons and the power is taken from the abutment shaft
through the medium of pulleys and belts or gear wheels, any known means of
regulating and governing the flow of water to the engine may be employed for
regulating its power.
The pumps may be used for any purpose when it is required to lift and force
fluids or semi fluids, and may be employed as a fire engine by supplying it with
suitable shut off valves and constructed for ordinary use at the sametime,
A very good proportion for Blowers in which the revolvers do not require as much

page_text: strength as in Rotary pumps is to make the inscribed circle about 1/8th less in
diameter than the pitch circle and then take 3/4th the difference between the
diameters of the pitch circle and the inscribed as a radius for describing the small
convex curve instead of 3/rds the difference between them as before described, and
also using this same dimension (3/th the difference between the pitch and inscribed
circle) instead of the entire difference as before mentioned as the distance to be
stepped off on the inscribed circle, as the point from which the larger convex
surface of the Piston is described.
r
If desired the abutment shafts D D may be supplied with centre pieces for
attaching wood laggings so as to furnish the working surfaces of the abutments of
the blowers with wood in such cases the outline of their working surfaces will
be formed according to the rules or methods hereinbefore described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Martin Benson in the Great Seal Patent Office on the 27th March
1883.
:
MARTIN BENSON of N° 52 Chancery Lane London IMPROVEMENTS IN "ROTARY
PUMPS AND BLOWERS:"-A Communication to me from Abroad by Francis
Marion Roots of Connersville Fayette County State of Indiana United States of
North America.
My Invention relates to that class of Rotary Pumps in which two or more
rotating abutments or pistons co-act together and with the shell in which they are
encased force a current of water or other fluid in one direction without permitting
backward escapement of same under pressure and is supplemental to my Patent
for Improvements in Rotary Blowers and Pumps dated September 27th 1881
N° 4158. The object of my present improvement is to produce pistons capable of
sustaining a heavy pressure with the least possible friction between the abutting
parts and to ensure perfect contact between the abutments during their entire
revolutions. It also consists in certain novel features of construction by which the
effectiveness of the machine is increased and its interior working parts protected
from sediment, or heavy foreign substances.
In Letters Patent N° 4158 granted to me September 27th 1881 for Rotary
Blowers and pumps I describe a method of producing pistons which insures
perfect contact between them during their entire revolution. The centres from
which the arcs and contact points are described are in an inscribed circle of about
one twelfth less diameter than the pitch circle. Pistons so constructed answer every
purpose for a blower or other engine in which the required pressure is usually about
one or two pounds per square inch and never exceeds five pounds but in pumps to be
used for fire purposes the pressure ranges from one hundred to one hundred and fifty
pounds per square inch. It is therefore necessary in this class of machines that the
size of the shafts be increased and that the thickness of metal around the shaft should
not be less in any part than one half the diameter of the shaft. To obtain these results
the abutments must necessarily be contracted in the direction of their major axis
and correspondingly widened in the direction of their minor axis. The method
described in said Patent N° 415881 will not produce such pistons because the
describing centres are too far from the axis of rotation. When the centres from
which the abutting surfaces are described are brought out near to the axis, as they
must be to produce these heavier pistons I have found that the abutments will not
clear each other when the convex and concave arcs meet in curves which are arcs
of equal circles, but that in order to keep up perfect contact with the least possible
friction the convex arcs must be compound curves and must meet the concave
contact surfaces in an arc of a smaller circle as hereinafter described. I have also
discovered a system for obtaining the centres from and the radius by which the
smaller arcs are described, So that by my present invention I am enabled to
construct pistons of any required strength as will be fully understood from the
following description.
In order to give a fuller understanding of my invention reference is made to the
accompanying drawings and letters of reference marked thereon.
•
Fig. 1. Sheet. 1. is a diagram illustrating my method or system of obtaining the
points from and the radii by which all the contact surfaces of my abutments are
described.
Fig. 2. Sheet. 2. is partly an end elevation and transverse section of my Improved
Pump.
Fig. 3. is partly a side elevation and longitudinal section of the same,

page_text: Fig. 4. is an end view of the base plate showing an elevation of the standard in
which the end of the abutment shafts revolve
Fig. 5 is a plan of the pump.
Fig. 6. Sheet 3 is a transverse vertical section of an arrangement for Hydraulic
Engines
And Fig 7. is a sectional elevation of the same.
The mode of constructing the revolving abutments or pistons of my machine is
as follows.
The abutment shafts D, D, are placed the requisite distance apart depending upon
the size of the machine to be constructed. Two equal circles are described around
the shaft centres by a radius equal to one half the distance between said centres these
pitch circles are divided by sectors into eight equal parts, one of these dividing
lines x, x pass when extended through both shaft centres, the diagonal lines are
marked z z.
Within the pitch circle and from its centre I describe a smaller circle
which I term the inscribed circle about one eighth more or less in diameter than
the pitch circle. The difference between the diameter of this circle and the pitch
circle (within limits hereinafter mentioned) determines the strength of the
abutments. The smaller the inscribed circle the heavier or thicker will be the
abutments through the, waist or minor axis, and vice versa, The points from which
the outer convex curves and inner concave contact surfaces are described I obtain
by taking two thirds the difference between the diameters of the inscribed and pitch
circles, and then with one point of a divider on the point i where the line x cuts
the inscribed circle I step off this distance on the inscribed circle upon each side
of the line x and obtain the points 2. From these points as centres the opposite
convex arcs of the abutments are described by a radius r, extending from said
points across the line x to the point where the diagonal lines 2, 2, cut the pitch
circle.
From these points as centres the convex arcs and concave contact surfaces are
described by the same radius as clearly appears from an examination of the
diagram (Fig. 1.)
It should be understood that the inscribed circle must not be so small as to
throw the point ³ across the diagonal lines z, 2,. As before stated the convex curves
must meet the concave contact surfaces in arcs of smaller circles or in other words
the points formed by the meeting of the convex and concave curves of equal circles
must be dressed off to arcs of smaller circles.
The centre and radius of the smaller arcs I obtain by taking two thirds of the
difference between the diameters of the pitch and inscribed circles as the radius and
with one point of the dividers on point where the concave curve or point of contact
is cut by the inscribed circle. I step off on the inscribed circle with the other point of
the divider this distance which gives with this point as a centre I connect point it
with the convex surface of the piston, This gives the exact shape the curved
surfaces of the pistons must have to move without friction and yet keep up perfect
contact. The curve in the waist of the abutments or bottom of recess is described
by a radius from a point in the line x. No arbitrary rule for describing this
curve, however is necessary it is only essential that it be cut back far enough for
the free passage of the end of the pistons. The ends of the pistons are the same
as I have shown and described in my Patent N° 4158 of September 27th 1881 and
the method of dressing the pistons is substantially the same as described in said
Patent with this addition the arc of the smaller circle herein shown I find is more
conveniently dressed off to the templete by a tool of suitable shape as described in
my said Patent for dressing the concave surfaces than by centering the
piston at ¿¹
Pistons constructed with their convex arcs composed of a compound curve
described from points and is make a perfect machine as the pressure forward is
constant without any backward escapement of the fluid. But I do not limit myself to
the exact curve described for the smaller arc as these are in contact with the opposite
abutments but a very short time during each revolution should perfect contact not

page_text: be kept up during this short time it is evident that the backward escapement
would be so small as not to materially affect the usefulness of the machine nor do
I limit myself to the exact location of the points i as these may be slightly varied
and still produce a more effective machine than any other now known.
A very good proportion for Blowers in which the revolvers do not require as
much strength as in Rotary Pumps is to make the inscribed circle one eighth less in
diameter than the pitch circle and then take three quarters the distance between the
diameters of the pitch circle and the inscribed circle as a radius for describing the
small convex curve instead of two thirds the distance between them as before
described, and using three quarters the difference between the pitch and inscribed
circle as the distance to be stepped off on the inscribed circle as the point ³ from
which the larger convex surface of the piston is described.
The following is a description of the other working portions of one arrangement
of my improved pump.
The case or shell of the pump is composed of two semi-cylindrical shells C and
two end plates C¹ which are secured to the shell by means of screw bolts-A A are the
revolving abutments or pistons which may be placed side by side as shown in the
drawing or one above the other The end plates C¹ have projecting flanges H at
top and bottom and are bolted to flanges formed on the pedestal or suction chamber,
said suction chamber may be bolted to the bed plate For they may be cast in one.
The suction pipes B B¹ may be placed at the side or bottom of the pump as shown
in Fig. 2. E is the outlet pipe of same-The journal boxes rest upon supports I
cast on the end plates C-The shafts DD are geared together by means of suitable
gear wheels G which may be cut or cast, said gear wheels are encased in a housing J
which is supported by flanges formed on the end of the journal boxes K; I also
provide my pump with pulleys L L¹ one on either shaft, outside of which the
shafts are supported by standards M M¹ and are securely bolted to the base plate F.
The packing N around the shaft in the chamber at either side of the end plates is
held and compressed by the glands O.
The other working portions of the pump are constructed essentially similar to
that described in my former Patent N° 4158 of 1881 excepting the abutment or piston
shafts are packed where they pass through the heads or ends of the case and a
receiving chamber is made separately or in the bed plate over which the piston or
abutment case is attached and also the suction pipe. The abutment shaft revolves
in bearings attached to the ends of the casing and in standards fixed to the bed
plate the shafts are provided with gear wheels at each end of equal diameter for
keeping the abutments in proper revolving position one with the other. The pump
may be worked through the medium of gearing or belts over pulleys attached
to each abutment shaft and at opposite ends of the machine or they may be worked
by applying Engine power direct or through the medium of gearing to the end of
one or both abutment shafts and arranged so that their cranks will be at right
angles, or any other known means of applying power may be employed to work
the pump.
The abutments or pistons are usually made of cast iron for blowing purposes but
may be made of sheet metal or steel by being shaped or stamped out in a cold or heated
state to the proper form in suitable dies or forming pieces. When the abutments
are thus made of sheet metal or steel it will be better to make them in half sections
or pieces and bolt or rivit them together at suitable points. The piston shafts
are provided with arms or centre pieces for attaching the sheet metal abutments to
them in any known convenient manner.
In some cases the packing glands are used for forming bearings for the piston or
abutment shafts to work in. Provision is made not shewn in the Drawings to
prevent dirty water from the pump getting between the shaft and bearing portion
of the gland this is done by forming a groove on the inside of the gland near its
inner end and a similar groove on the outside of the gland opposite the one on the
inside, holes are made in the gland opposite the grooves and thereby put the inside
and outside groove in the gland in communication and the groove on the outside of

page_text: the gland is put in communication with an opening made through the side of the
packing chamber. With the parts thus provided with grooves and openings it
prevents any dirty water that may come from the pump through the packing from
getting between the shaft and bearing portion of the packing gland by being
drawn off from the gland through the grooves and openings and thereby prevent
cutting or injury to the shaft where it works in the gland with any foreign matter
that may be in the water.
The machine may be used as a very efficient Hydraulic Engine, for this purpose
water pressure is made to revolve the pistons A A and the power is taken from the
abutment shafts D D through the medium of pulleys and belts or gear wheels, any
known means of regulating and governing the flow of water to the Engine may be
employed by regulating its power. One method of constructing a machine of this
kind is shown in Figs 6 and 7 Sheet. 3. Other methods will readily suggest them-
selves to persons skilled in the Art. The Pumps may be used for any purpose where
it is required to lift or force liquids fluids or semi fluids and may be employed as a
fire engine by supplying it with suitable shut off valves and constructed for
ordinary use at the same time.
If desired the abutment shafts D D may be supplied with centre pieces for
attaching wood laggings so as to furnish the working surfaces of the abutments of
the blowers with wood in such cases the outline of their working surfaces will be
formed according to the rules or methods hereinbefore described.
Having now described the mode of constructing and operating my said improve-
ment, what I claim is.
1 The art of producing pistons for Rotary Pumps or Blowers which consist in
constructing abutting contact surfaces in arcs of circles described from point i² in
an inscribed circle by a radius extending from said point 2 across line x to a point 2³
where the diagonal lines z, z. cut the pitch circle said point being obtained substan-
tially as specified.
2nd The method of constructing the inner convex curve of Rotary Abutments for
Pumps which consist in forming said curves upon arcs of circles the radii of which
are equal to two thirds of the difference between the diameters of the pitch and
inscribed circles. The centre of said circles being the point on the inscribed
circle-which centres are the length of the radius distance from the point it where
the concave abutting arcs cut the inscribed circle.
3rd Pistons for rotary pumps constructed substantially as specified; that is
having the convex abutting surfaces composed of arcs of different circles, the centres
from which said arcs are described being the points 22 and 2 and the concave
abutting surfaces also describe said point as a centre.
4th. The combination substantially as herein before set forth of the Pump case, the
enclosed rotary Abutments and their actuating mechanism with the pedestal forming
the pump support and an enlarged chamber or reservoir between the supply pipe
and the pistons.
5th. The combination substantially as specified of the pump case, the rotary
pistons and the actuating mechanism, The Pedestal, bed plate F and shaft supporting
standards M M'.
In witness whereof. I the said Martin Benson have hereunto set my hand and
seal this twenty second day of March in the year of Our Lord 1982