IMPROVEMENTS IN VENTILATING APPARATUS
Year: 1880

page_text: LETTERS PATENT to William Cunningham, of Dundee, in the County of Forfar,
North Britain, Engineer, for an Invention of "IMPROVEMENTS IN VENTILATING
APPARATUS."
PROVISIONAL SPECIFICATION left by the said William Cunningham at
the Office of the Commissioners of Patents on the 20th May 1880.
WILLIAM CUNNINGHAM, of Dundee, in the County of Forfar, North Britain,
Engineer. "IMPROVEMENTS IN VENTILATING APPARATUS."
This Invention relates to the ventilating of large buildings or spaces of any kind
by means of apparatus operating according to the system or principle of that
described in the Specification of Letters Patent granted to the present applicant,
and dated 19 October 1875 (No. 3621), the object of the present improvements
being to modify the form or construction of the air pumping or air moving apparatus
so as to render its application in some positions or situations more convenient or
advantageous than that described in the earlier Specification referred to.
In carrying out the Invention a large pump or air mover, of simple and light
construction, is employed, having a piston or pistons moving at such speed, and
having valves of such relatively large aggregate area as that no more pressure is
imparted to the air than that barely sufficient for its displacement. In one
modification in which a single piston is used it works in a casing of a cylindrical
form, baving closed ends, and made with two openings which extend from end to
end of the cylindrical part, and which are adjacent but separated from each other
by a partition. A shaft to which reciprocating, rotatory, or angular motion is
imparted is placed in the axis of the cylinder and has the piston attached so as to
radiate from one side of it. The partition which separates the openings extends
within the cylinder to the axis, forming an abutment, and it or another partition
extends externally so as to divide a valve chamber into two compartments. The
cylinder may be placed in any suitable position, but in one convenient arrangement
it is placed with its axis horizontal and with its openings and the valve chamber
underneath. This valve chamber is conveniently made of a rectangular form and
enclosing the lower half (or more or less) of the cylinder, the partition dividing it
being vertical and extending along its middle. An external vertical partition
placed at right angles to the internal partition and at the middle of the axis of the

page_text: cylinder divides the inlet passage or space from the outlet passage or space, and the
sides and ends of the valve chamber are fitted with inlet and outlot valves
respectively on opposite sides of the external partition. These valves may be of
the kind described in the carlier Specification hereinbefore referred to, being
by preference formed of impermeable cloth made with two plies of light cotton
cloth having rubber between them, and their frames are secured by hooks, or
latches, or bolts, admitting of their being at any time casily removed to give access
to the interior.
The piston has an angular motion, the extent of which is, by preference, so much
of a complete circle as will leave only sufficient width of openings for the ingress and
egress of the air into and out of the cylinder. In some cases, however, it may bo
more convenient to give a less extent of angular movement to the piston, and in
some cases two pistons placed by preference diametrically opposite to each other
may be fixed on one shaft, in which case two abutment partitions and pairs of
inlet and outlet openings will be required.
The piston shaft is in one modification worked by means of a pinion fixed on it
externally and acted on by a rack worked by a motive-power engine, which may
be of the hydraulic kind described in the earlier Specification herein before referred
to, or of any other suitable kind worked by water, gas, or steam. Instead of the
pinion and rack, a pulley or sector-pulley and cord, or any other equivalent arrange-
ment may be used which will give the desired extent of angular movement, it
being desirable for the motion of the piston to be as uniform as possible during the
larger portion of its stroke, with the commencement and termination gradual.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said William Cunningham' in the Great Seal Patent Office on the
18th November 1880.
WILLIAM CUNNINGHAM, of Dundee, in the County of Forfar, North Britain,
Engineer. "IMPROVEMENTS IN VENTILATING APPARATUS."
My said Invention relates to the ventilating of large buildings or spaces of any
kind by means of apparatus operating according to the system or principle of that
described in the Specification of Letters Patent granted to me and dated 19 October
1875 (No. 3621), the object of my present improvements being to modify tho
form or construction of the air pumping or air moving apparatus so as to render its
application in some positions or situations more convenient or advantageous than'
that described in my earlier Specification referred to.
.
In carrying out my Invention a large pump or air mover of simple and light
construction is employed, having a piston or pistons moving at such speed and
having valves of such relatively large aggregate area as that no more pressure is
imparted to the. air than that barely sufficient for its displacement.
In one
modification, in which a single piston is used, it works in a casing of a cylindrical

page_text: form and is in the form of a radial plane fixed on a shaft placed in the axis of the
casing. There is a stationary radial plane which acts as an abutment, and, the
piston reciprocates angularly so as to approach this abutment on opposite sides at
each end of its stroke. The cylindrical casing communicates by two openings, one
on each side of the abutment, with two compartments of a valve chamber, each
compartment having in it a set of inlet valves and a set of outlet valves. The
cylindrical casing may be placed in any suitable position, but in one convenient
arrangement it is placed with its axis horizontal and with its openings and the
valve chamber underneath. The valves may be of the kind described in my earlier
Specification herein before referred to, being by preference formed of impermeable
cloth made with two plies of light cotton cloth having rubber between them, and
their frames are secured by hooks, or latches, or bolts, admitting of their being at
any time easily removed to give access into the interior.
The piston has an angular motion, the extent of which is, by preference, so much
of a complete circle as will leave only sufficient width of openings for the ingress
and egress of the air into and out of the cylinder. In some cases, however, it may
be more convenient to give a less extent of angular movement to the piston; and
in some cases two pistons placed, by preference, diamètrically opposite to each
other may be fixed on one shaft, in which case two abutment partitions and pairs
of inlet and outlet openings will be required.
The piston shaft is in one modification worked by means of a pinion fixed on it
externally and acted on by a rack worked by a motive-power engine, which may
be of the hydraulic kind described in my earlier Specification hereinbefore referred
to, or of any other suitable kind worked by water, gas, hot air, or steam.. Instead
of the pinion and rack, a pulley or sector-pulley and cord, or any other equivalent
arrangement may be used which will give the desired extent of angular movement,
it being desirable for the motion of the piston to be as uniform as possible during
the larger portion of its stroke, with the commencement and termination gradual.
It is not necessary for the motive-power apparatus to be exclusively arranged for
the ventilating apparatus, as such apparatus where it is convenient may derive its
power from a source which also supplies power to other apparatus or machinery.
And in order that my said Invention and the manner of performing the same
may be properly understood, I hereunto append two Sheets of explanatory Drawings
to be hereinafter referred to, and representing one modification of my improved
ventilating apparatus.
Figures 1 and 2 on Sheet 1 of the Drawings are an end elevation and a transverse
vertical section of the apparatus, and Figures 3 and 4 on Sheet 2 are a plan and a
partly sectioned side elevation. In these Figures the same reference numerals are
used to mark the same or like parts wherever they are repeated.
The apparatus shown in the Drawings is constructed with a framework and
casings made principally of wood, some of the frame pieces being strengthened by
iron plates. Externally the apparatus resembles a horizontal cylinder partly
embedded in a rectangular box, which last forms the lower part of the structure.
The cylinder 5 within which the radial piston 6 moves angularly consists of a
cylindrical shell formed by longitudinal boards or staves built on circular end
frames 7, and strengthened by longitudinal ribs 8 and segments 9 placed externally,
the inside surface being kept clear to be swept over by the piston 6. The end
frames 7 are closed by internal boarding. The shell 5 does not form a complete
cylinder, there being an open space at the bottom which, extending the whole
Length of the cylinder, is divided into two openings 10, 11, by a vertical longitudinal
partition 12, which also divides the lower part of the valve chamber into two
compartments 13, 14, and extending up inside the cylinder forms an abutment
separating the space on one side of the piston 6 from that on the other side thereof.
The piston 6, which is made of light boards fixed on wooden ribs, is fixed on a
bladed centre 15 fast on a central shaft 16, and a small hollow cylindrical centre 17
surrounds the shaft, making up a convenient size for working in contact (or nearly
so) with the inner edge of the abutment 12. The weight of the piston 6 is

page_text: balanced by a counterweight 18 on a lever fixed on one end of the shaft 16. The
travel of the piston 6 is from the outer edge of one bottom opening 10, round by
the upper part to the outer edge of the other bottom opening 11, and vice versa,
drawing in and expelling the air alternately through each opening 10, 11.
The lower parts of the ends and the whole of the sides of the lower rectangular
part of the casing or structure are occupied by the inlet and outlet valves, there
being inlet valves at one end and occupying half the side of each valve chamber
compartment 13, 14, and outlet valves at the other ends and occupying the other
halves of the sides. Externally the space is divided by a vertical partition 19
placed transversely at the middle of the length of the cylinder, so that all the
inlet valves are on one side of this partition and all the outlet valves on the other
side thereof. It will however be obvious that the external arrangements will in
practice be varied in different cases, passages being provided to lead the air to the
apparatus and other passages to lead the air from it, according to the particular
requirements of each case. The valves, which are of the kind described in my
carlier Specification hereinbefore referred to consist of horizontal strips 20 of a
suitable light impermeable cloth fixed by their upper edges to rectangular frames 21
mado with light horizontal and vertical grating bars to support the valve strips 20
when closed. The valve frames 21 are held in their places by hooks 22, or latches
or bolts 23, and can be removed and replaced with great facility.
In the modification shown in the accompanying Drawings the piston 6 is worked
by means of a small hydraulic engine 24 of the kind described in my earlier
Specification hereinbefore referred to. This engine is supported on a bracket 25 at
one end of the apparatus, and one end of the piston shaft 16 is passed through two
bearings in the top of the standard 26, between which bearings there is fast on the
shaft a pinion 27 which is in gear with the rack 28 fixed to or formed on the piston
rod of the engine.
Having thus particularly described my said Invention and the manner of
performing the same, I have to state that I do not restrict myself to the precise
details herein described or delineated, but that what I believe to be novel
and original, and claim as the Invention secured to me by and in terms of the
herein before in part recited Letters Patent is,―
1. The arranging or combining together of the parts of a ventilating apparatus,
substantially in the improved manner hereinbefore described.
2. The combination of a cylindrical casing having in it an angularly reciprocating
radial piston with a rectangular valve chamber fitted with flat rectangular valve
frames, substantially as herein before described.
3. The placing or forming of the valves on loose rectangular frames held in
position by hooks, latches, or bolts, substantially as hereinbefore described.
In witness whereof, I, the said William Cunningham, have hereunto set my.
hand and seal, this Sixteenth day of November, in the year of our Lord
One thousand eight hundred and eighty.
ADVINCITLI
דז דווו
IAM CUNNINGHAM.
WILLIAM
(L.S.)