IMPROVEMENTS IN EXHAUSTING, FORCING, COMPRESSING, HEATING, COOLING, AND APPLYING AERIPORM BODIES, AND IN APPARATUS THEREFOR
Year: 1864

page_text: LETTERS PATENT to David Laidlaw and James Robertson, both of Glasgow,
in the County of Lanark, North Britain, Engineers, for the Invention'
of "IMPROVEMENTS IN EXHAUSTING, FORCING, COMPRESSING, HEATING, COOLING,
AND APPLYING AERIPORM BODIES, AND IN APPARATUS THEREFOR."
Sealed the 25th April 1865, and dated the 28th October 1864.
PROVISIONAL SPECIFICATION left by the said David Laidlaw and James
Robertson at the Office of the Commissioners of Patents, with their
Petition, on the 28th October 1864.
We, DAVID LAIDLAW and JAMES ROBERTSON, both of Glasgow, in the County
of Lanark, North Britain, Engineers, do hereby declare the nature of the
said Invention of "IMPROVEMENTS IN EXHAUSTING, FORCING, COMPRESSING,'
HEATING, COOLING, AND APPLYING AERIFORM BODIES, AND IN APPARATUS THEREFOR,"
to be as follows, that is to say:
This Invention comprises various improvements in the details of arrange-
ments and apparatus for forcing, compressing, heating, cooling, and applying
aeriform bodies.
One improved piece of apparatus is suitable for exhausting illuminating.
gas, and is useful in gas works. It consists of a cylinder having its ends closed,
but with a horizontal shaft passing through them and through its axis. This
shaft which is driven by a belt and pulley, or otherwise has fast on it an oval.
impeller or piston, the two diametrically opposite parts of which work in close.

page_text: but easy contact with the internal cylindrical surface. A valve hinged to an
opening in the top side of the cylinder is pressed down by a spring so that its
free edge follows and keeps constantly in contact with the oval impeller, and
closing the opening which is the outlet for the gas, as each extremity of the
impeller comes round. The inlet for the gas is made adjacently to the hinged
side of the valve, and the impeller.. is..made..to rotate in such.a. direction that
each extremity as it comes round passes the outlet first and then the inlet.
The impeller may have three parts in contact with the cylinder, and instead
of being oval, it may be of any suitable curved form.
In making a gas exhauster with a common reciprocating pump, there is
introduced by this Invention à regulator valve which by throttling or partially
checking the flow when the pump is at the middle of its stroke, moderates
oscillation and induces uniformity in the pressure. For such regulator valve
to work well, there should be a reservoir or equivalent space between it and
the pump.. In a convenient modification the reservoir is formed in the framing
of the machine, and the valve shaped much like an ordinary stop,cock is fixed
directly on the crank shaft for driving, the pump, the gas passage with its valve
chamber being disposed with the crank shaft passing through it. Such a
regulator may be applied to the rotatory exhauster herein-before described, but
it is not so much needed therewith on account of the more uniform action with
that apparatus.
When gas or air is to be forced or compressed into small bulk or to
considerable pressure, it is by this Invention proposed to employ a quick
percussive action. Thus one modification of the improved apparatus resembles
an ordinary steam' hammer, the compressing plunger or piston forming or being
attached to the lower end of the hammer, bar, or steam piston rod, or to the
moving cylinder if such is used; whilst the compressing cylinder is placed
immediately under the steam cylinder. There is no crank shaft, and the steam
valves are worked by gearing similar to what is applied to steam. hammers.
It is intended to make the moving part of a weight which will greatly assist
and intensify the downward compressing stroke, and maintain its force more
fully, to the end of the stroke, than is done with the ordinary crank pumping
movement. By these means air may be compressed to a great density to be
conveyed by piping or otherwise to great distances for working various engines.
such as hoisting, pumping; pressing, sewing, and similar machines, and for
other useful. purposes. such as the raising or forcing of corrosive and other
liquids by causing the compressed air to act on the surface thereof in closed
vessels and force the liquid through pipes or channels. The great force and
speed of the compressing. piston.or plunger will necessitate extra strength in

page_text: the cylinder and passages; and means will be required for removing the great
heat generated by the compression. For this purpose channels must be formed
for. currents of cold air or water, such currents being formed when necessary
by pumps worked by cross heads fixed to the main piston rods. Or, if it is
not necessary to keep the air free from moisture, cold water may be admitted
into the cylinder or air. passages to mingle with and act directly on the air.
To increase the percussive character of the compressing stroke it.is.proposed
in some cases that the piston acting directly on the air shall not rise as high
as the piston bar or rod acting on it, so that the latter in descending will
acquire some momentum before it strikes and begins to move the compressing
piston. A buffing appliance such as a cushion of rubber may be applied to
the piston or cylinder bottom to soften the termination of the stroke.
A very advantageous application of the described arrangements for com-
pressing air is in apparatus for cooling or refrigerating by means of the
re-expansion of compressed air. In this case the action should be swift, the
pressure great, and the impact sharp of the compressing piston on the air, so
as to render sensible as much as possible of the heat contained in the air, and
that heat should be removed as speedily and as completely as possible whilst
the air is in a compressed state, so that on its re-expansion it may exert the
greatest cooling effect. In one modification the valve gear of the steam
cylinder may be arranged as in some steam hammers to be worked by a small
steam engine, and each portion of the air may be subjected to two or more
strokes. The compressed air may be cooled by being passed through apparatus
constructed like a surface condenser; or like a reverse current refrigerator; and
part of the cooling surface may be acted on by what may be termed the "waste
cool air," that is the re-expanded air after it has extracted as much heat as it
advantageously can from the brine or other substance subjected to its action,
but when it may be still considerably cooler than the atmosphere. The com-
pressed air before or on entering the cooling vessel may be divided into two
or more jets, and these jets may be arranged to meet each other from opposite.
directions so as by the collision of the currents to render sensible more of the
heat in the air in order to assist its removal. If-it-is not required to keep the
compressed air free from moisture, water, may be injected directly into it, or
water may be maintained by means of a loaded floating valve at a suitable
level in the cooling vessel, and the compressed air may be forced through-the
water into the vessel. If the compressed air is to be used for cooling: buildings
or apartments it may after, being cooled be allowed to escape by a suitably
loaded valve directly into the space to be cooled, or if too cold and greater
quantity is required, it may be made to act in a turbine so as to drive a fan
"

page_text: for drawing in air' from the atmosphere, being made to mix with and reduce
the temperature-of-such induced air. Or it may be discharged in a jet form
in a channel or dúct admitting air from outside, when it will induce a strong
inward current and mix with and cool it.
Another important application of the improved compressing apparatus is in
compressing illuminating gas into portable or other vessels for convenience of
storage or conveyance where ordinary gas holders or pipes are not available.
For example, a gas lamp may be made in a portable form with a receptacle
for compressed gas in its base provided with a valve opening inwards' to admit
the compressed gas, and with a suitable valve to regulate its supply-to 'the
burner or burners.
.:
.:
.: :."
A convenient modification of the direct-acting apparatus herein-before
described, may be used for exhausting gas or air, or for impelling it through
passages, an ordinary pump being substituted for the compressing cylinder, and
the parts being worked more slowly. Or instead of an ordinary pump an
inverted vessel may be attached to the bottom of the steam piston rod, and
worked in a water lute like that of a gasholder whilst inlet and outlet pipes are
provided for the gas or air. With both these arrangements the regulator valve
herein-before referred to should be used.
In another extremely simple and convenient arrangement for impelling and
at the same time heating air for drying and ventilating purposes, steam is
made to work a turbine of simple construction fixed on the same spindle with
an air blowing fan, and both steam and air are then passed through different
spaces or passages arranged-like those of a surface condenser in order that the
steam after working the turbine may give up to the air its' remaining heat.
The turbine is by preference of a disc form turned truly outside, and the inlet
steam pipe is united to the bearing, and the steam presses a flange on the
-tubular boss or centre of the turbine against the bearing, thereby keeping the
joint tight. The turbine is placed with its axis vertical, the steam entering
from below, and the pressure on the flange partially bearing up its weight.
In some of the modifications of apparatus herein-before described in which
reservoirs or chambers for containing, cooling, or expanding the aeriform body
are required, they may for the sake of convenience, compactness, or economy,
be formed in or as part of the framing; thus in the "steam hammer-like,"
arrangements the standards supporting the steam cylinders may with advan-
tage be made hollow for the said purpose.
"

page_text: 5
SPECIFICATION in pursuance of the conditions of the Letters Patent; filed
by the 'said David Laidlaw, and James: Robertson, in the Great Seal
Patent Office on the 28th April 1865.
"
TO ALL TO. WHOM THESE PRESENTS SHALL COME, we, DAVID
LAIDLAW, and JAMES ROBERTSON, both of Glasgow, in the County of Lanark,
North Britain, Engineers,.send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-eighth day of October, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-eighth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto us, the
said David Laidlaw,. and James Robertson, Her special licence that we, the
said David Laidlaw, and James Robertson, our executors, administrators,
and assigns, and such others as we, the said David Laidlaw, and James
Robertson, our 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 EXHAUSTING,
FORCING, COMPRESSING, HEATING, COOLING, AND APPLYING ABRIFORM, BODIES, AND IN
APPARATUS THEREFOR," upon the condition (amongst others) that we, the said
David Laidlaw, and James Robertson, our executors, or administrators, by an
instrument in writing under our, 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 we, the said David Laidlaw and James Robertson,
do hereby declare the nature of our said Invention, and in what manner-
the same
is to be performed, to be particularly.described. and ascertained in
and by the following statement in. writing, reference. being had to the accom-
panying Drawings, that is to say :-
.:
Our said. Invention comprises various improvements in the details of
arrangements and apparatus for exhausting, forcing, compressing, heating,
cooling, and applying aeriform bodies.
And in order that our said Invention, and the manner of performing the
same may be properly understood, we have hereunto appended four Sheets of
explanatory Drawings, to be herein-after referred to, and representing various,

page_text: modifications of apparatus embodying our improvements. The same reference
numerals mark the same or like parts in all the Figures in which they occur.. :
One improved piece of apparatus is suitable for exhausting illuminating
gas, and is useful in gas works.
Four modifications of it are shown upon Sheet 1 of the accompanying
Drawings, Figures 1 and 2 being transverse and longitudinal vertical sections
of one modification.
The apparatus consists of a cylinder 1, having its ends closed, but with a
horizontal shaft 2 passing through them and through its axis. This shaft 2,
which is driven by a belt and pulley 3, or otherwise, has fast on it an oval
impeller or piston 4, the two diametrically opposite parts of which work in
close but easy contact with the internal cylindrical surface. A valve 5 hinged
to one side of an opening 6 in the top side of the cylinder is pressed down by
a spring 7, so that its free edge follows and keeps constantly in contact with
the oval impeller 4, and closing the opening 6, which is the outlet for the gas
as each extremity of the impeller comes round: The inlet 8 for the gas is
made adjacently to the hinged side of the valve 5, and the impeller 4 is made
to rotate in such a direction indicated by the arrow 9, 'that each extremity as
it comes round passes the outlet 6 first, and then the inlet. The spring 7 for
keeping the valve 5 in contact with the impeller 4 can be nicely adjusted by
means of two screws 10, as will be easily understood from the Drawing.
Figures 3 and 4 are transverse and longitudinal vertical sections of a second-
modification, which differs from that just described merely in having the
cylinder 1 divided into two compartments by a disc 11, with separate impellers
or pistons 4 in each compartment, but placed at right angles to each other, so
that the valves 5 are closed at different times, and a more uniform current of
gas is thereby maintained. The impeller or piston 4 may have three parts in
contact with the cylinder, as shown in transverse and longitudinal vertical
section in Figures 5 and 6, and instead of being oval it may be of any
suitable curved form.
Figures 7 and 8 are transverse and longitudinal vertical sections showing
the application of steel packing strips 12 pressed outwards by springs to the
ends of the impeller or piston 4. To prevent these strips 12 from getting
into the inlet 8 and outlet 6, they are made to project into and work in
grooves in the cylinder end covers.. Similar packing strips may be applied to
work against the cylinder end covers.
In making a gas exhauster with a common reciprocating pump, there is
introduced by this Invention a regulator valve, which by throttling or partially
checking the flow. when the pump is at the middle of its stroke, moderates

page_text: oscillation, and induces uniformity in the pressure. For such regulator valve
to work well there should be a reservoir or equivalent space between it and
the pump.
.
Figures 9, 10, and 11, on Sheet 2 of the accompanying Drawings, in front;"
side, and back elevation, and partly in section, represent a convenient modi-
fication in which the reservoir 13 is formed in and arranged as the base of the
framing of the machine. The pump 14 is worked by a horizontal crank
shaft 2 above, and this shaft is driven by means of a belt and pulley 3, or it
might be driven in any other convenient way. The regulator valve is shown
in section in Figúrė 11, and consists of an oscillating piece 15, which works:
nearly in contact with the gas outlet 16. The piece 15 is fixed on a rocking.
shaft 17, which passes out through a stuffing box, and is fitted externally with
a lever, which is actuated by a connecting rod 18 from à crank on the
shaft 2 above.
Figure 12 is a plan, and Figure 13 is a side elevation of a modification in
which a steam cylinder 19 is added for driving the machine, which is thus
rendered quite self-contained. The pump 14 is double-acting, and both it and
the steam cylinder 19 are placed horizontally on a bed frame 13, which forms
the reservoir. The gas enters by an inlet pipe 20 into a compartment pro-
vided for the purpose in the bed frame, and rises thence into the pump
cylinder 14; whence it descends into the reservoir compartment.
Figure 14 is a transverse section of the pump cylinder, and shows the
arrangement of the inlet and outlet passages and valves, which are the same
at both ends of the cylinder. The steam and pump pistons are both on one
rod, which is connected in the usual way to a crank shaft 2, having a fly wheel;
on it. In this modification the regulator valve 15 is fixed directly on the
crank shaft 2, and the outlet 21 for the gas is arranged to cross the shaft.
The valve 15 is shown in Figures 15 and 16, which are sections at right"
angles to each other. It is formed with 'segmental pieces, which as the shaft
> rotates, alternately cover and uncover the passage through, and these pieces
are placed on the shaft in such positions that they check the flow most when
the pump piston is at the middle of its stroke. Such a regulator may be
applied to the rotatory éxhauster-herein-before described, but is not so much
needed therewith on account of the more uniform action with that apparatus.
. When gas or air is to be forced or compressed into small bulk or to con-
siderable pressure, it is by this Invention' proposed to employ a quick percussive"
action. Convenient arrangements for obtaining this action will resemble
ordinary steam hammers, and one modification is shown in front elevation in
Figure 17, in vertical and horizontal section in Figures 18 and 19, and inª

page_text: back elevation in Figure 20. The compressing plunger or piston 22 is,
attached to the lower end of the hammer bar or steam piston rod 23 (or it
might be to the moving cylinder if such were used), whilst the compressing
cylinder 24 is placed immediately under the steam cylinder 25. There is no
crank shaft, and the steam valve 26 is worked by gearing similar to what is
applied to steam hammers, and consisting in this example of a two-armed
rocking lever 27, which is tilted by an adjustable piece 28 on the rod 23, and
which acts on the valve through links and levers. The rod 23 and com-
pressing, piston.22.are made of a weight which will greatly assist and intensify.
the downward compressing stroke, and maintain its force more fully to the
end of the stroke than is done with the ordinary crank pumping movement..
The piston 22 is packed with a cup leather, and the air enters to the under.
-side when the. piston is raised by a passage and valve 29; whilst it issues.
through a loaded valve 30, passing first through a number of plies of wire
gauze 81, which act as a cushion to the piston 22. The passage with the
loaded-valve 80 communicates by a passage indicated by dotted lines at 32;in,
Figure 19, with a reservoir 33 formed in the base of the hammer, standard 34..
The exit passage from the reservoir 33 is indicated by dotted lines at 35 in.
Figure 19. The great force and speed of. the compressing piston or plunger.
necessitates, extra strength in the cylinder 24, and passages and means are
required for removing the great heat generated by the compression. For this
purpose a cistern, or casing, 36 is formed round the lower part of the cylinder
24, and this cistern is kept filled with cold water. By these means air may
be compressed to a great density to be conveyed by piping, or otherwise, to
great. distances for working various engines, such as hoisting, pumping,.
pressing, coal cutting, sewing, and similar machines, and for other useful
purposes, such as the rising or forcing of corrosive and other liquids, by
causing the compressed; air to act on the surface thereof in closed vessels,
and force the liquid through pipes or channels.
Figures 21 and 22 are side and back elevations of a modification in which.
a.small. donkey, engine, 37, is provided for working the valve of the direct-
acting cylinder 25; this engine driving a small fly wheel shaft, 38, a crank on
which is connected to the valve rod. Figure 28 is. a sectional side elevation.
in which the water cistern (36) is dispensed with, and a pipe 39 is introduced.
to admit water into the compressing cylinder 24, for the purpose of directly
cooling the air when the air is not required to be free from moisture.
To increase the percussive character of the compressing stroke we in some
cases arrange so that the piston acting directly on the air does not rise
as high as the piston bar or rod acting on it, so that the latter in descending

page_text: will acquire some momentum before it strikes and begins to move the
compressing piston.
When using compressed air for working machines of the kinds herein.
before indicated, it is important to maintain the full pressure, notwithstanding.
that a greater or less quantity of air may be in the reservoir or reservoirs; and,
we secure this by putting the bottom of the air reservoir in communication
with a head of water, the inlet and outlet for the air being in the top of
the reservoir....
Figure 24 on. Sheet 8 of the accompanying Drawings is a. longitudinal
vertical section of a compressed air reservoir arranged in this way.. The air
enters by the pipe a, and issues by the pipe 6, whilst the water enters by the
bottom pipe c. The high-pressure town's water, may be used, or water: from
a sufficiently elevated cistern, or which has a head or pressure obtained in any
way. The water is not wasted, as when the reservoir is filled with: air.it is.
simply forced back towards its source, returning into the reservoir as the-air
is used: A reservoir of this kind; for example, may be placed at the bottom
of a mine shaft for air to work coal-cutting machinery, when the water pipe c
may be in connection with the pump pipes, or with a cistern on the surface..
An advantageous application of arrangements for compressing, air similar
to those herein-before described is in apparatus for cooling,.refrigerating; or
freezing, by means of the re-expansion of compressed air. In this case, the
action should be swift, the pressure great, and the impact sharp of the com
pressing piston on the air, so as to render sensible as much as possible' of the
heat contained in the air, and that heat should be removed as speedily and. as
completely as possible whilst the air is in a compressed state, so that on its
re-expansion it may exert the greatest cooling effect.
Figure 25, Sheet 3 of the Drawings, is a horizontal-section, Figure 26. is a
transverse vertical section, and Figure 27 is a longitudinal vertical section of
a modification of these arrangements as adapted for freezing. The comp
pression pump details are like those shown in Figures 17. to 20. The.
compressed air passes by a pipe 40 into a sort of surface condenser 41, and
inside of this condenser it passes through a system of piping 42, composed of.
horizontal rings connected by-short vertical tubes alternately at opposite sides.
On entering the first ring the air divides into two currents, which pass by.
opposite sides of the ring to the first vertical connecting piece, where, they
meet from directly opposite directions to rise and divide, and meet again.
repeatedly in each ring until the top is reached... The object of dividing the
air into separate currents or jets which meet each other, is for the collisions of
the currents to render sensible more of the heat in the air, in order to assist.its.

page_text: removal. The air. issues from the, top. of the condenser 41. by a pipe 43,
which admits it into the main air space 44 of the cooling or freezing
trough 45. In this space the air expands, and in, doing, so extracts heat
'from a series of .moulds. m.. which are supplied with water or other liquid to
be frozen or.cooled. The.expanded air.passes off by an outer space (46, which
outer space serves as a non-conducting jacket for, the, main inner space 45.)
into a jacket space 47 surrounding the condenser 41, and thence by a worm 48
through the middle of the condenser, finally returning to the compressing
pump.by a. pipe 49, or being ejected into the atmosphere. What may be
termed the "waste cool air," that is, the, re-expanded air after it has extracted
'as much heat as it. advantageously can from the water, brine or other substance
subjected to.its action, but when it may be still considerably cooler than the
atmosphere,.is thus utilised, so as to aid in the cooling action in the condenser
41, by being passed through the space 47. and worm 48.. The tubes:42 and
'worm 48 are surrounded by water, which enters by a pipe 50 from a pump 51,
the plunger of which is attached to a cross head upon the ram or piston
rod 23; or, the water. may be supplied from any convenient source..
.Figures. 28 and 29 are transverse and longitudinal vertical sections of a
modification in which instead of the surface condenser arrangement provision
is made for cooling the.air by introducing water into it. The framing of the
compressing machine. is formed, with, a reservoir.33, into which the air passes
when compressed.. This reservoir is divided by a diaphragm .52 composed of
several plies of wire gauze, through which the air has to pass in an upward
direction. A little. above the diaphragm 52 a pipe with a perforated rose 53
admits.water, which, mingling with the air, abstracts heat therefrom, and, passing
down to the bottom compartment, passes off by a valve 54, when it attains a
depth sufficient to lift the float, 55 connected thereto. The air before passing
to the cooling.or.freezing trough 45 is in this modification made to yield back
part of the power employed in compressing, it being passed into a cylinder 56
placed just under the steam cylinder, 25, and acting on a piston 57 on the rod
or ram 23. The valve 58 for admitting the air to this cylinder may.be
actuated by the same rod as the steam cylinder valve 26. On leaving the
cylinder 56 the air passes by the pipe 43 to the trough 45, wherein it acts as
in the modification already described. If the compressed air is to be used
for. cooling buildings or apartments, it may after being cooled be allowed to
escape by a suitably, loaded valve, directly into the space to be cooled; or if
too cold, and greater quantity is required, it may be made to act in a turbine,
so as to drive a fan for drawing in air from the atmosphere, being made. to
mix with and reduce the temperature of such. induced air. The combined

page_text: turbine and fan herein-after- described is very suitable apparatus for this
purpose. Or the compressed air may be discharged in a jet form in a channel
or duct admitting air from outside when it will induce a strong inward
current, and mix with and cool it.
Another important application of our improved compressing apparatus is
in compressing illuminating gas into portable. or other vessels for convenience
of storage or conveyance where-ordinary gasholders or pipes are not available.
For example, a gas lamp may be made in a portable form, with a receptacle
for compressed gas
in its base, provided with a valve opening inwards to admit
the compressed gas, and with a suitable valve to regulate its supply to the
burner or burners.
i
A convenient modification of the direct-acting apparatus herein-before
described.may be used for exhausting gas or air, or for impelling it. through
passages, an ordinary pump 14 being substituted for the compressing cylinder,
and: the parts. being worked more slowly...
Figures 30 and 31, on Sheet 4 of the accompanying Drawings, represent
such an arrangement in front sectional elevation and in side elevation. Or
instead of an ordinary pump an inverted vessel 59, such as is shown in
Figures 32 and 33, which represent another modification, may be attached.to
the steam piston rod 28, and work in a water lute 60, like that of a gasholder,
whilst inlet and outlet pipes 61, 62, are provided for the gas. or. air.
both these arrangements the regulator valve (15) herein-before referred to
may be used with advantage.
With
Another extremely simple and convenient arrangement for impelling and at
the same time heating air for drying and ventilating is shown in Figures 34
and 35, which are respectively a, sectional side elevation and a plan. In this
arrangement steam entering by a pipe 63 is made to work a turbine 64 of
simple construction fixed on the same spindle 65, with an air blowing fan 66,
and both steam and air are then passed-through different spaces or passages
arranged in a shell 67, like those of a surface condenser, in order that the
steam after working the turbine 64 may give up to the air its remaining heat.
The turbine 64 is by preference of a disc form, turned truly outside, and the
inlet steam pipe 63 is united to the bearing 68, and the steam presses a flange
69 on the tubular boss or centre of the turbine against the bearing 68, thereby
keeping the joint tight. The turbine is placed with its axis vertical, the
steam entering from below, and the pressure on the flange 69 partially bearing
up its weight.
Figures 36 and 37 are a section and elevation of a modification of the air
fan and steam driving turbine combined and arranged so that they may under
.

page_text: all circumstances be fitted in the most convenient position possible when used
for inducing a current of air with or without heat: The casing of the air fan
is formed with two outlets 70, 71, so that a discharge duct may be. attached
to whichever is most convenient, the other being then closed by a cover 72..
Having thus particularly described our said Invention; and the manner in
which the same is or may be performed, we have to state that we do not
restrict ourselves to the precise details herein described or delineated; but,
that what we believe to be novel and original, and claim as the Invention
secured to us by the herein-before in part recited Letters Patent is, the
exhausting, forcing, compressing, heating, cooling, and applying of aeriform
bodies in the improved modes and by apparatus, the parts of which are
combined together, substantially as herein-before described.
In witness whereof, we, the said David Laidlaw and James Robertson,
have hereunto set our hands. and seals, this Twenty-sixth day of
April, in the year of our Lord One thousand eight hundred and
sixty-four.
Witness,
EDMUND HUNT,
Patent Agent,
Glasgow.
(LS.)
DAVID LAIDLAW.
JAMES ROBERTSON. (L.B.)