IMPROVEMENTS IN ROTARY PUMPS, BLOWERS, AIR PUMPS, OR VENTILATORS, AND IN PRIME MOVERS
Year: 1880

page_text: LETTERS PATENT to John William Melling, of Wigan, in the County of
Lancaster, Engineer, for an Invention of "IMPROVEMENTS IN ROTARY PUMPS,
BLOWERS, AIR PUMPS, OR VENTILATORS, AND IN PRIME MOVERS."
PROVISIONAL SPECIFICATION left by the said John William Melling at the
Office of the Commissioners of Patents on the 17th June 1880.
JOHN WILLIAM MELLING, of Wigan, in the County of Lancaster, Engineer.
"IMPROVEMENTS IN ROTARY PUMPS, BLOWERS, AIR PUMPS, OR VENTILATORS, AND
IN PRIME MOVERS."
These improvements are partly in the novel form or shape given to the internal
moving parts in that kind of machine that consists of two or more revolving
propellers, exhausters, or pistons fitting in a case that is provided with inlet and
outlet passages.
Through and across the case are carried shafts or spindles, on which the propellers
are mounted, and by which they are driven. They are also fitted with toothed
wheels or other means to preserve their relative positions.
One of this kind of machine is known as the double eight gas exhauster.
I make the two revolving propellers or exhausters (where two only are used) in
part of two equal sized cylinders, in each of which are two recesses, and on which
are two projections or pistons.
The pistons are of a width to make up the difference between the diameter of
the revolving cylinder and that of the case in which it works; each recess is
slightly deeper than the width of a piston. By preference I form the pistons on
the one side of a radial line, and on the other side by a curve of such a radius as
shall just clear the edge of the recess in the other propeller.
When used as a motive power engine the pistons on the leading side would be
formed of a curve, and on the other side part curve and part of a radial line; or
both sides may be of the same shape, particularly if the machine is required to
work both ways; the sides would then be formed partly of curves, or part curves
and partly of straight lines..
The recesses are so shaped as just to allow the points or ends of the pistons to

page_text: The propellers are carried by shafts or spindles, on which also are secured
toothed wheels so geared together that when they revolve the parts of the propellers
that are cylindrical roll together, and the recesses in one propeller are opposite to
projections or pistons on the other, and thus cach alternately forms an abutment
for the other, and presents a recess for the piston of the other to pass through.
.
A further improvement consists in the use of self adjustable packing or packings
provided for and fitted to the pistons (when packings are required) to more
perfectly prevent the leakage of the liquid or fluid from one side to the other; this
is accomplished by fitting springs or somo elastic substances on the pistons. I
prefer to use springs covering the backs and ends of the pistons and a portion of
the front, to which they are secured in such a manner as to leave the inner ends
free and so far clear of the body of the cylinder as to allow the liquid or fluid to
come between them and the backs of the pistons; in some cases to maintain an
equilibrium of pressure, and in others to force the springs out. In all cases the
springs press against the edges of the recesses, into and through which they pass,
and thus prevent any leakage through the recesses; or the springs may be fitted
into the recesses with their outer ends free, and so that the fluid can enter between
the springs and the recesses to press the springs outwards against the backs of the
pistons. Other packing pieces inay be fitted to the ends of the revolving propellers,
or to the ends or covers of the case if required.
The pistons are in some cases all in a piece with the central part; in others
either the whole or a part of each piston is separate, and so attached that a liner
can be introduced when required to take up the wear; or the face of the piston
may be separate, and so fixed to the body of the piston that it can be adjusted
when worn.
The shafts or spindles may work in ordinary bearings, or in bearings so arranged
as to form stuffing boxes to prevent leakage along them.
For some purposes I prefer to form a collar on each shaft; these collars to work
against suitable shoulders provided at one side of the case, the other ends of the
shafts to revolve in bearings that are closed at the ends. This arrangement allows
whatever pressure is inside the case to act on the area of the closed in ends of the
shafts, and consequently to keep the collars in contact with the shoulders formed
near the other bearings on the case, and thus prevent leakage.
If required relief valves may be titted in the pistons or body of the propellers to
allow of the passage of the liquid from the front to the back of the pistons when
an excessive or dangerous pressure is produced.
Passages are forined in the covers when required to allow of the escape
backwards of a portion of the liquid which is enclosed in the recess by the
advancing piston, and thus avoid any unnecessary compression.
When air or other fluid is operated upon, as for the purpose of producing a
current or blast, coned tubes or pipes may be fitted round the outlet pipe or
passage, so that the body of air moved by passing through the machine may, when
discharged, induce currents and move other air or fluid without its having to pass
through the machine; or when used for exhausting, the inlet and outlet passages
may both open into the same pipe or passage, and be so shaped as to induce a
current, the air which is being drawn into the machine through the inlet pipo or
passage setting in motion a body of air towards the outlet passage, which when
made to discharge through a coned tube or tubes will induce and expel the air
already set in motion past the inlet orifice.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John William Melling in the Great Seal Patent Office on the 16th
December 1880.
JOHN WILLIAM MELLING, of Wigan, in the County of Lancaster, Engineer.
"IMPROVEMENTS IN ROTARY PUMPS, BLOWERS, AIR PUMPS, OR VENTILATORS, AND
IN PRIME MOVERS."
These improvements consist partly in the novel form or shape given to the
internal moving parts in that kind of machine that consists of two or more
revolving propellers, exhausters, or pistons, fitting in a case that is provided with
inlet and outlet passages, and also in the application of springs and packing pieces
to the pistons, propellers, shafts, and cases of rotary pumps, blowers, ventilators, or
prime movers; and in order that my Invention may be fully understood and readily
carried into effect, I will describe the accompanying two Sheets of Drawings,
reference being had to the figures and letters marked thereon; similar letters of
reference indicate corresponding parts on the different views.
On Sheet 1, Fig. 1 is a cross section, Fig. 2 is an elevation partly in section, and
Fig. 3 is a plan partly in section of a rotary pump or blower to which my Invention
is applied. a is the casing; b, b, are the shafts; b', 61, are a pair of spur wheels;
c, c, are the propellers, on which are formed or fixed the projections or pistons d, d;
and d', d, are packing pieces extending the whole length of the propellers, which
can readily be replaced when worn; these packing pieces may be applied to all the
projections, or in some cases they may be dispensed with. The fluid or liquid enters
at the aperture at the top of the casing and is drawn or forced in the direction
indicated by the arrows.
Fig. 4 is a cross section and Fig. 5. is a plan in section of a pump or blower
designed for high pressure, to which my Invention is applied. d², d³, are adjustable
spring packing pieces fastened on the pistons. When the piston in revolving enters
the recess in the propeller the spring bears against the edge of the recess, and
prevents the liquid or fluid from escaping through it. A space is left between the
end of the spring and the body of the propeller to admit the liquid or fluid between
the spring and the piston. The pressure of the liquid or fluid helps to keep the
spring against the edge of the recess while the piston is passing through it. f,f, are
end packing plates, through each of which is an aperturo g to allow of the escape of
a portion of the liquid enclosed by the piston when entering the recess in the
propeller; the apertures 9 also allow the liquid or fluid to get to the back of the
plates to maintain an equal pressure on both sides of the plates. The plates are
pressed against the ends of the propellers by springs e of india rubber or other
material. Four of these springs e are formed of elastic washers, which surround the
shafts and prevent the escape of liquid or fluid along them.
Fig. 6 is a cross section and Fig. 7 is a plan, partly in section, showing a pump
or blower in which the pistons or projections & are made separate from the propeller,
and attached to the propeller by screws or other convenient means, and the
bearings of the propeller shafts are formed like stuffing boxes so as to allow of
packing being inserted, in order to provent the escape of the liquid or fluid along
the shafts. is a relief valve to allow the liquid or fluid to escape when the
pressure becomes too great.
Fig. 8 shews a cross section of a blower used for producing a current or blast, in
connection with which coned tubes are used, by means of which currents of air can
be induced, and a greater body of air than has passed through the machine will bo
forced through the discharge pipe.
Fig. 9 is a cross section of a motive steam engine; the pistons are formed with
one side curved and the other side partly curved and partly of a radial line (or plane

page_text: surface); two of the pistons shewn have the outer portions d³, which are liable to
wear, made separate, and secured by screws or otherwise. In the recesses in tho
propellers are fitted springs h, which bear against the curved sides of the pistons
when they pass through the recesses to prevent the escape of liquid or fluid through
the recesses. Instead of fitting springs in the recesses, springs may be fitted on to
the pistons, as before shewn and described.
Fig. 10 is a cross section of a pump or blower, in which the pistons are shewn of
a suitable shape for working in either direction, and they may be used either with
or without springs, as shown.
Fig. 11 is a sectional elevation of a pump or blower; in this view two kinds of
packing plate are shewn. g¹ is a recess in one of the packing plates f, which recess
I prefer to use when it is desirable to have only a small aperture, as shewn, to
connect the space at the back of the plate with the interior of the casing. To
maintain the equilibrium of pressure the packing plate fl is provided with an
elastic spring or packing e' of india rubber or other material, which only encloses a
portion of the space at the back of the plato; this spaco is connected with the
interior of the casing by the aperture g. The space behind the lower portion of
the packing plate fi communicates with the lower portion of the casing by the
aperture g; this arrangement allows a more equal pressure to bo maintained on
each side of the packing plate f¹, oven when there is a great difference in the
pressure in the lower and upper portions of the casing; the plate ƒ and the casing
are grooved or recessed to retain the spring or packing e' in its place.
Fig. 12 shews an exhauster arranged with the coned inlet pipo K and the coned
outlet pipe l, both opening into one pipo or passage, through which the air has to
be drawn and discharged; the air which is being drawn through the inlet pipe K
and through the machine sets in motion a body of air towards the outlet pipel, and
the air discharged through the outlet pipe carries it forward and expels it; a much
larger body of air is thus discharged than is passed through the inachiue.
Although I have usually shewn the pistons with one side curved and one side a
plane surface, radiating from the axis, the angle of the plane side may bo varied, or
it may be partly plane and partly curved, substantially as shown in Fig. 9, and
though I have shewn two packing plates f, in most cases one only need be used.
Having stated the nature of my Invention, and described the manner of
performing the same, I wish it to be understood that I do not limit myself to the
exact shape or details shown and described, as they may be varied or modified.
And I declare that 1 claim,-
1. The shape of the pistons shewn and described in reference to Figs. 1, 9,
and 10.
2. The packing pieces
as shewn and described in reference to Fig. 1.
3. The application of springs to the pistons, substantially as shewn and described
in reference to Figs. 4 and 10.
4. The springs h fitted in the recesses of the propellers, substantially as shown
and described in reference to Fig. 9.
5. The packing plates f and f' in combination with the springs e and e³, as
shewn and described in reference to Figs. 5 and 11.
In witness whereof, I, the said John William Melling, have hereunto set my
hand and seal, this Fourteenth day of December, One thousand eight
hundred and eighty.
JOHN W. MELLING. (L.S.)