IMPROVEMENTS IN BLAST ENGINES
Year: 1869

page_text: LETTERS PATENT to William Niell, the younger, of Bold, in the
County of Lancaster, Engineer, for the Invention of "IMPROVEMENTS
IN BLAST ENGINES."
Sealed the 13th May 1870, and dated the 16th November 1869.
PROVISIONAL SPECIFICATION left by the said William Niell at the
Office of the Commissioners of Patents, with his Petition, on the
16th November 1869.
I, WILLIAM NIELL, the younger, of Bold, in the County of Lancaster,
Engincer, do hereby declare the nature of the said Invention for "Im-
PROVEMENTS IN BLAST ENGINES," to be as follows:-
My improvements relate to the valves of blast engines, and to the
method of working the same, and consist, firstly, in the use of a slide
valve or valves at each end thereof connected together or made in one
piece with a passage from one to the other. The air I propose to take
in by a passage corresponding to the exhaust of a steam cylinder, and to
deliver it into the valve chest, from whence it passes into the conduit
pipe.
Secondly. My Invention consists in the use of apparatus whereby the
air passages are closed when the piston reaches the end of its stroke, and

page_text: remain so until it has made a portion of its return stroke, when the
inlet and outlet passages are fully opened, the object being to prevent
the air which has been partially compressed from escaping to the outlet.
For this purpose I propose to employ ordinary tappets or cams, which
shall keep the valves closed until the piston has made a portion of its
return stroke. In large engines I propose to use a supplementary steam
cylinder for actuating the air valves. The steam valves of this cylinder
are opened by the main piston, but prevented from actuating the air
valves by means of ordinary tappets or cams until, as in the former
case, the air piston has made a portion of its return stroke.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Niell in the Great Seal Patent Office on
the 16th May 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
NIELL, the younger, of Bold, in the County of Lancaster, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixteenth day of November, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said William Niell, the younger, Her special license
that I, the said William Niell, the younger, my executors, administrators,
and assigns, or such others as I, the said William Niell, the younger, 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 BLAST ENGINES,"
upon the condition (amongst others) that I, the said William Niell, the
younger, by an instrument in writing under my hand and seal, 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 William Niell, the younger, 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 ascertained
in and by the following statement and accompanying Drawings, that is to
say :-
The main feature of my Invention has for its object the use of slido
valves and to prevent the air which has been compressed from escaping
at the outlet. For this purpose I employ apparatus whereby the air
passages are closed when the piston arrives at the end of its stroke,
and by which the said valves are so held until a portion of the return
stroke has been effected, after which the inlet and outlet passages are
fully opened.
In the accompanying Drawing Fig. 1 represents a longitudinal section
of the blast engine with the steam cylinder for working the same con-
nected, and also the valve apparatus; Fig. 2 is a plan view of the same
parts.
The steam engine cylinder is shewn at 1 mounted on a bed plate 2,
and the piston rod at 3 working in slides 4. The crank shaft is at 5,
upon which is the excentric 6, the rod 7 of which is connected to a
lever 8 vibrating on a stud 9, and connected at its other end to the
steam valve rod 10. At 11 is the cylinder of the blast engine, and at
12 the air inlet, which is formed on the side of the said cylinder after
the manner of the exhaust of a steam cylinder, and at 13 the air outlet
communicating with the valve box 14, the inlet and outlet ports of the
cylinder being at 15, 16. The valves which I employ are shown at
17, 18, one at each end of the cylinder, and are constructed as slide
valves connected to a rod 19, which is jointed to another rod 20 con-
nected at its other end to a lever 21 capable of rocking upon the stud 9
and fast with another lever 22, the lower end of which is provided with
a roller 23 in contact with a cam 24 fixed to the crank shaft 5. At 25
is a third lever fast with those shewn at 21, 22, and therefore also.
rocking upon the stud 9, and carrying at its outward end a roller 26 in
contact with a second cam 27 mounted on the crank shaft 5. These
two cams are so formed that when one is acting so as to force its roller
outward the other is so formed as to allow its roller to pass inward; it
may therefore be considered that the two surfaces correspond to those of
a grooved cam acting upon one lever, and this arrangement may indeed,
if desired, be employed, the only object in using two being facility of
construction in obtaining the right curves.
Connected with the valve rod 19 is a supplementary steam cylinder A,
but at present I shall not allude to it, but confine the description of my
.

page_text: .
Invention in connection with the parts already pointed out. Suppose
the air piston 28 to be travelling in the direction of the arrow, the air
is being compressed in the space 29 of the cylinder, the valves 17, 18,
being closed. These valves, however, are to be opened when the air has
been compressed, and this is effected by the rotation of the cams 24, 27,
turning the levers 21, 22, 25, in the direction of the arrows, thus sliding
forward the rod 20-in the direction of the arrow thereon. This will
open the ports 15, 16, and the compressed air will pass out through
the port 15, as shewn by the arrow, while the induction 16 will be
opened, as shewn by. the dotted arrow, after which the cams will of
course for a time have a dead run. The piston 28 now arrives at the
end of its stroke and commences its return, at which time according
to the usual method of working the induction and eduction would be
reversed, and any compressed air which was left in the space 29 would
pass out through the inlet. According. to, my Invention I prevent this
by so forming the cams 24, 27, that they suddenly close the passages by
bringing the valves into the position shewn, and by keeping them in
that position until the-air piston shall have performed such a portion of
its return stroke. as. will allow the compressed air which is left to expand
to its normal volume, after which the same operations as those above.
described are repeated at the right hand end of the cylinder. It will thus
be seen that the valves 17, 18, are entirely controlled by the form of the
cams 24, 27 (or a grooved cam), and that any required amount of space
may be gained for the expansion of the remaining compressed air by
altering the form of the said cams.
In large blast engines I prefer to supplement the apparatus above
described with an auxiliary steam cylinder A, adapted so as to work the
slide valves 17, 18, but only when the shape of the cams above described
will allow the levers 22, 25, to turn upon their centres, the said auxiliary
engine being merely charged with power ready to act when the cams
permit it to do so, and these cams may therefore under these circum-
stances be more properly called variable abutments. At A as before
stated is a steam cylinder and piston provided with the usual slide valve,
to the rod of which is jointed a rod 30 connected at its other end to a
lever 31, which turns upon a centre pin 32 carried by a lever 33 which
vibrates on a fixed centre 34. The lower part of the lever 31 is jointed
at 35 to the cross head 36 of the engine and consequently moves there-
with. Assuming again the position above alluded to, the space 38 is
already charged with steam, the cross head on moving forward in the

page_text: direction of the arrow thereon having acted upon the rods and levers
above described, and having shifted the slide valve 37. so as to allow
steam to pass into the said space 38, whereby the piston 39 will be
forced in the direction of the arrow. thereon, and will tend to move the
valves 17, 18, in the same direction, but this is prevented by the shape
of the cams 24, 27, which as before stated serve as an abutment, and no
effect will take place; but when by the revolution of these cams the
levers. 22, 25, are allowed to move, then the charged power in the
cylinder 38 exerts its force and shifts the air valves 17, 18, as before
described, and the same operations will take place on the return stroke,
the steam cylinder A acting as the motive power, and the cams 24, 27,
as the restraining power.
I have above shewn and described the air valves 17, 18, as formed in
separate parts, but if desired they may be formed in one part, as in tho
case of long D valves, but still acting at both ends of the cylinder or
"gridiron," or rotatory valves on the same principle may be used.
Having thus described and ascertained the nature of my said Inven-
tion, and the manner in which the same is to be performed, I desiro
it to be understood that I do not limit myself to the details shewn and
described; but claim as secured to me under the above in part recited
Letters Patent,―
Firstly. The use of slide or other such valves as aforesaid for blast
engines combined with cams or similar apparatus, for the purpose set
forth.
:f
Secondly. The use of a steam cylinder for moving the said valves
combined with cams or similar apparatus for regulating the time when
the said steam power shall act.
In witness whereof, I, the said William Neill, the younger, have
hereunto set my hand and scal, this Fourteenth day of May, in
the year of our Lord One thousand eight hundred and seventy.
WILLIAM NETLL TB