IMPROVEMENTS IN MARINE STEAM ENGINES FOR DRIVING SCREW AND OTHER PROPELLERS, AND IN SCREW PROPELLERS
Year: 1859

page_text: PROVISIONAL SPECIFICATION left by Richard Archibald Brooman at
the Office of the Commissioners of Patents, with his Petition, on the
7th December 1859.-A communication from abroad by Nicolas
Hippolyte Labrousse, of Paris.
I, RICHARD ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of
London, E.C., Patent Agent, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN MARINE STEAM ENGINES FOR DRIVING SCREW AND
OTHER PROPELLERS, AND IN SCREW PROPELLERS."-(A communication to me from
abroad by Nicolas Hippolyte Labrousse, of Paris, to be as follows:-
The first part of this Invention consists in lining the top and bottom of
steam cylinders internally as well as the faces of the piston with wood, in order
to prevent the steam condensing when coming in contact with those parts. In
both cases the wood is painted or stained white in order to diminish loss of
heat by radiation.
The Invention also consists in lining with felt or other like non-con-
ducting materials the steam ports, slide valves, and those portions of the sides
of the cylinder which are alternately exposed and cut off from the action of
the steam. A sheet of copper covers or holds the felt in position. The felt
can be replaced by an air chamber if found more convenient. To avoid loss
of steam, the Inventor maintains a continuous supply of steam at the back of
the valves through a small pipe furnished with a tap. A screen is sometimes
placed above the valves of the air and other pumps, in order to prevent as
much as possible friction or shocks acting on the valve seats.

page_text: The Invention further relates to certain arrangements of screw propellers,
and consists in forming the rear guide or support for the propeller insuch
manner that the upper bearing of the axle can be raised. By lowering the
guide the axle becomes disengaged, owing to the shape of the lower bearing;
by this means the propeller is thrown out of a perpendicular line on the
bearing formed in the stern post. To place the propeller in its working posi-
tion the upper bearing of the journal is brought back and slightly raised in
such manner that the shaft no longer rests on the bearing formed in the stern
post, which for this purpose is allowed a slight play. To raise the propeller it
is placed in the same position as before; the tapered end of the propeller shaft
is made long enough to extend about half through the nave or boss of the
propeller formed hollow for its reception, and is fixed to the propeller by a
strong screw; springs bear against this fastening screw to prevent its working
loose. To withdraw the fastening screw a key is employed which extends from
the deck, and is guided by a cross piece formed on the upper part of the frame,
by means of which the propeller is raised. The key enters the notch in the
head of the fastening screw through a conical guide, whereby its introduction
is facilitated. The frame is jointed to permit of the lowering of the rear bar
or end thereof when the upper bearing is drawn back: When the propeller is
about to be hoisted out of the water one of the blades enters a notch formed
in a catch suspended from the cross bar or upper piece of the frame, prevents
the propeller revolving, and at the same time prevents the joints in the frame
bars from playing. The sides of the frame are formed of round iron bars
covered with copper. The rear bar is surrounded with a triangular case, in
order that the water which strikes against the after supporting post may not
meet with any obstacle. When the propeller shaft is drawn wholly inwards,
the opening through which it passed is closed by a slide to prevent the admis-
sion of water. The stuffing box is made tight by placing an indian-rubber
washer therein between a metallic washer and the bottom of the box; a screw
or screws are employed to compress the caoutchouc washer; the weight of the
after part of the shaft is borne by a block which is free to slide on or in guides.
The to-and-fro motion of the shaft is obtained by means of a screw thread cut
on the shaft in gear with a corresponding internal thread of a wheel, which is
free to revolve in suitable bearings, and is caused to rotate by a worm on a
vertical tube passing up between decks and worked by a capstan. In the
interior of the tube a rod is placed, on the upper end of which internal rod a
click or catch is fitted by which the worm is thrown in and out of gear, thereby
releasing the worm wheel, which revolves with the screw shaft. The extreme
end of the propeller shaft is keyed to a joint piece, when the shaft is to be run

page_text: in the key is removed, and that part of the shaft connected to the joint is
swung round on a quadrant, which allows the disconnected part of the propeller
shaft space to be run in the required distance. The lower ends of the foremost
and aft stern posts are connected by means of a metal shoe, which forms a
continuation of the keel.
The Invention also consists in the application of plumbago or black lead to
coat screw propellers, in order to facilitate their passage through the water.