IMPROVEMENTS IN PACKING THE STUFFING BOXES OF STEAM AND OTHER ENGINES
Year: 1871

page_text: PROVISIONAL SPECIFICATION left by James Smart at the Office of
the Commissioners of Patents, with his Petition, on the 3rd July
1871.
I, JAMES SMART, of Barking, in the County of Essex, Engineer, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
PACKING THE STUFFING BOXES OF STEAM AND OTHER ENGINES," to be as
follows:
My said Invention has for its object the reducing to what I believe to
be the lowest possible minimum of the friction which is attendant upon
the modes of packing stuffing boxes as hitherto adopted, and conse.
quently by my said improvements to ensure the economizing of power
and of the packing and lubricating materials.
My improvements in packing stuffing boxes consist in the substitution
of the following arrangement in place of the other methods which have.
hitherto been used; and some of these I am aware have been designed
with a view to attempt the remedying of the defects herein-before
referred to, and which will now by the use of my said Invention be
successfully overcome.

page_text: In order to accomplish this, I employ, according to the first portion
of my said Invention, a helical spring of steel or other metal having
sufficient elasticity, the extreme length of the spring being equal to the
depth of the stuffing box to be packed. Within and between the
interstices of the said helical spring I coil an elastic packing of round,
oval, or other form in cross section, and the said spring with packing
interposed is then placed within the stuffing box, and surrounding the
rod, as for instance, in a steam engine, the piston rod where it works
through the stuffing box.
The second portion of my said Invention consists in a modification to
be made to the packing gland, according to which I form a number of
perforations in the gland, to give in the aggregate an atmospheric
pressure on the top of the spring sufficient to supply, when the steam
pressure is removed from the upper side of the piston, the necessary
amount of compression to the coils of packing in order to ensure the
same being brought to the form of the stuffing box, and to press on the
rod passing through it on the packing gland being screwed down, but
which screwing down requires to be very moderate indeed. The force
of the steam when acting in excess of the atmospheric pressure on the
upper side or above the piston also compresses the packing, which
instead of being rigid, as in the usual modes of packing stuffing boxes,
it is kept moving or reciprocating within the stuffing box in a direction
of motion which is inverse to that of the rod. The travel or stroke of
the elastic packing will remain nearly if not quite a constant, and so
when the gland has been once adjusted future screwing down and
tightening up will be rendered unnecessary, and so obviate the loss
arising at present from the great friction attendant upon the ordinary
modes of packing stuffing-boxes, the rod not being pressed or gripped
by the packing with any greater force than is actually necessary to
ensure tightness without destructive and wasteful friction. The advan-
tages of my improvements, in this respect especially, for locomotive
and other high speed and high-pressure engines will be self-evident
to any engineer.
I wish it to be understood that in carrying out the first portion of
my said Invention, it is not indispensable that a metallic spring be
employed, as india-rubber or other suitable elastic packing may be
coiled around the rod in the stuffing box, and confined between two
discs or circular plates at the top and bottom respectively of the stuffing

page_text: box. The pressure of the steam and atmosphere respectively acting upon
the said discs or plates is transmitted to the clastic packing so as to
ensure the same being compressed sufficiently, and to serve the same
purpose and act in the same manner as the herein-before described
arrangement of packing combined with a metallic spring.
In order to allow of the application of my Invention to the present
systems of stuffing boxes and glands, very trifling and inexpensive
alterations will be required to be made thereto.