IMPROVEMENTS IN CENTRIFUGAL MACHINES FOR THROWING AIR AND OTHER FLUIDS AND COMMUNICATING MOTIVE POWER THEREBY.
Year: 1874

page_text: LETTERS PATENT to Thomas Webster Rammell, of No. 4, West-
minster Chambers, Westminster, in the County of Middlesex, Civil
Engineer, for the Invention of "IMPROVEMENTS IN CENTRIFUGAL
MACHINES FOR THROWING AIR AND OTHER FLUIDS AND COMMUNICATING
MOTIVE POWER THEREBY.'
"
Sealed the 30th April 1875, and dated the 5th November 1874.
PROVISIONAL SPECIFICATION left by the said Thomas Webster
Rammell at the Office of the Commissioners of Patents, with his
Petition, on the 5th November 1874.
I, THOMAS WEBSTER RAMMELL, of No. 4, Westminster Ohambers,
Westminster, in the County of Middlesex, Civil Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN CENTRIFUGAL
MACHINES FOR THROWING AIR AND OTHER FLUIDS AND COMMUNICATING MOTIVE
POWER THEREBY," to be as follows :-
In a former Patent for centrifugal discs, No. 2718, dated 6 November
1860, I described the internal air ducts or passages to be of the
same transverse area throughout at whatever distance from the

page_text: centre a section might be taken, and the sum of the transverse areas of
all the ducts to be equal to the united areas of the apertures at the
centre through which the air is admitted. In a subsequent Patent for
centrifugal machines, No. 2608, dated 21st August 1868, I gradually
reduced the size of the ducts as they extended from the centre of the
machine outwards, and in such manner that while at their commence-
ment around the central apertures the mouths of the ducts were to be
collectively equal in area to the united areas of those apertures. The
transverse areas at any point outwards towards the rim or circumference
were to be inversely proportional to the increase there in the velocity of 1
rotation of the machine.
I now find that a more free flow of air may be obtained through the
ducts, and a fuller supply be given to the discharge vents by keeping
the ducts of the same transverse area from the central apertures up to a
point near to the rim or circumference of the machine, and thence ]
gradually reducing them down to the smaller transverse areas suitable
for the discharge vents in the form of a converging adjutage, and one of
my improvements consists in giving to the ducts this shape.
Another of my improvements consists in adding to the machine
externally an annular diverging adjutage affixed to the outer case or 2
structure and around the rim or circumference in such manner that the
machine may rotate within, and the discharge of air be effected through
it, and thus by ensuring a reduction in the velocity of the current
before it is allowed to escape a portion of its energy may be returned to
assist the flow within and towards the machine.
2
Other of my improvements consist in the mode of arranging the
central apertures of the machine and the side entrances admitting the
air, and in forming the junction there between the fixed and the moving
parts, and also in the designs for supporting the main shaft and for
obtaining convenient access at all times to the bearings, and in the g
general arrangement of the machine.
The methods [referred to in the last paragraph consist in making the
central apertures of a cylindrical form at the mouth and covering them
there with wood or other suitable material to bring them up to the
thickness of the entrance pieces; in making the entrance pieces also 3
cylindrical where they meet the apertures, and having them turned to a
true surface externally for the joint; in making the entrances diverge
'

page_text: outwards from the joint and of a square shape at the bottom for the freer
admission of the air; in attaching the entrance pieces to the girders
and sheets supporting the main shaft by suitable flanges and bolts ; and
in providing hollow trunks overlapping the plumber blocks and secured
to the girders for obtaining access at all times to the bearings.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Webster Rammell in the Great Seal Patent
Office on the 4th May 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
WEBSTER RAMMELL, of No. 4, Westminster Chambers, Westminster, in
the County of Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of November, in the year
of our Lord One thousand eight hundred and seventy-four, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said Thomas Webster Rammell, Her
special licence, that I, the said Thomas Webster Rammell, my executors,
administrators, and assigns, or such others as I, the said Thomas
Webster Rammell, my 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 CENTRIFUGAL MACHINES FOR THROWING AIR
AND OTHER FLUIDS AND COMMUNICATING MOTIVE POWER THEREBY," upon the
condition (amongst others) that I, the said Thomas Webster Rammell,
my executors or administrators, by an instrument in writing under my,
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 I, the said Thomas Webster Rammell, do
hereby declare the nature of my said Invention, and in what manner

page_text: the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:—-
In the Specification of a former Patent granted to me for "centrifugal
discs &c.," I described the internal air ducts or passages of the machine
as of the same or nearly the same transverse area throughout, at what-
ever distance from the centre a section might be taken, and the sum of
the transverse area of all the ducts as equal or nearly equal to the
united areas of the two apertures at the centre through which the air is
admitted. In a subsequent Specification of a Patent for "centrifugal
machines " I reduced gradually the size of the ducts or passages as they
extended outwards, and in such manner that while at their commence-
ment around the central apertures the ducts were to be collectively
equal or nearly equal in transverse area to the united areas of those
apertures their transverse area at any point outwards towards the rim or
circumference was to be reduced so as to be inversely proportioned to
the increase there in the velocity of rotation of the machine.
I now find that a more free flow of air may be obtained through the
ducts and a fuller feeding be given to the discharge vents, and also a
more gradual application of the power be effected by keeping the ducts
of the same or nearly the same transverse area (such area being about
equal to the united areas of the central apertures) from their mouths
around the central apertures up to a point or line near the rim or cir-
cumference of the machine, and thence gradually reducing them down
to the smaller transverse area suitable for the discharge vents in the
form of a converging adjutage, and one of my improvements consists in
giving to the ducts this shape.
In Sheet 1, Figures 1 and 2 are respectively a side view and a
transverse view of a centrifugal machine adapted for throwing air in
considerable quantity, the moving part being of the diameter of 32 feet.
A, A³, A", are the central apertures which are supplied through the
: rays B, B¹, B¹, with the fluid to be dealt with. C, C¹, C", C¹¹¹, are
radiating ducts made of equal transverse area throughout up to the
line D, D¹, D", and collectively equal or nearly so to the free area of the
two central apertures. E, E³, E", E, are the discharge vents of area
calculated to deliver the intended quantity of air at the velocity and
pressure given, and which I prefer to make of depth about equal to the
width, F, F, F", is the converging adjutage connecting each vent with

page_text: the larger portion of the duct, and which I prefer to make of length
equal to about four times the width of the vent though I do not confine
myself to this proportion.
Another of my improvements consists in adding to the machine
externally an annular diverging adjutage which I affix to the outer case
or structure in such manner that the machine may rotate within and the
discharge of air be effected through it with the object of reducing the
velocity of the current before it is allowed to escape, and thus preserving
a portion of its energy to assist the flow within.
G, G³, G", G¹¹¹, Figures 1 and 2, represent a diverging adjutage fixed
around the moving part of the machine in such manner that the
discharge is effected through it. It is shown of length equal to from
seven to eight times the width of the vents, the width at the narrower
end being equal to that of the vents and at the larger end about double
which I consider a good proportion (although I do not confine myself to
it), as the velocity of the discharge current is thus reduced fully one
half before it is allowed to escape.
In fixing the adjutage around the machine when it is an encased one
I prefer to use the arrangement shewn at G³, G", where a, a, a, &c., are
cast-iron bearers made with ribs and flanges to receive the segments of
plates (best of wood or sheet iron) b, b, b, &c., to which they are screwed
or bolted. The bearers are either built into the brickwork or masonry,
or supported by the chairs c, c, c, &c., and projecting pieces d, d, d, &c.,
as shown, but any other pattern of bearer and mode of attachment will
answer.
For open running or uncased machines I prefer to affix the adjutage,
as shown at G and G¹¹, and to make it entirely of cast or sheet iron
connected together as shown. H is a casting forming the bottom
support and securely fixed to the structure. I is one of two other
castings supporting the adjutage at the middle by cross bearers securely
fixed to the walls of the race or pit in which the machine works. The
rest of the segmental plates are built together in the manner of the
stones of an arch and are fixed to these three supports constituting a
complete ring, as shown. In order to make as close a joint as possible
between the fixed and moving parts of the machine I fill in the space
left in the wood or other soft material, as shewn at e, e, e, e.

page_text: Other of my improvements consists in the mode of arranging the
central parts of the machine comprising the apertures and side entrances
and the junction between the fixed and the moving parts, as shown in
Figures 1 and 2, and also in the method of supporting the main shaft,
shortening the length between the bearings, and obtaining access to the 5
journals at all times, as shown, and also in the general arrangement of
the machine, as shown.
In witness whereof, I, the said Thomas Webster Rammell, have
hereunto set my hand and seal, this Third day of May, in the
year of our Lord One thousand eight hundred and seventy- 10
five.