Improvements in or connected with Propeller or other Shafts of Steam Ships.
Year: 1892

page_text: Date of Application, 15th July, 1892
Complete Specification Left, 29th Mar., 1893-Accepted, 29th Apr., 1893
PROVISIONAL SPECIFICATION.
Improvements in or connected with Propeller or other Shafts of
Steam Ships.
I, WILLIAM HENRY ELLIS of Atlas Iron and Steel Works, Sheffield in the
County of York, Engineer do hereby declare the nature of this invention to be
as follows:-
It has been found, in the working of steam ships, that a chemical or electro-
chemical action takes place causing injury to the shafting by "pitting" it,
and the object of my invention is to provide improved means for overcoming this
action. Such shafts have already had applied to them brass casings or liners
usually of a thickness of " to inch shrunk on in lengths. This operation is
always attended with considerable risk of bursting the liners and the joints which
are burnt together frequently give way and therefore the value of this form of
casing or liner is materially diminished.
According to my invention I electrolytically deposit copper, or an alloy of
copper, upon shafts instead of employing the aforesaid brass liners or casings.
A suitable thickness of such copper or alloy of copper is one sixteenth of an inch,
but I do not limit myself to that thickness. By this means I avoid all danger
of liners or casings bursting or joints giving way in manufacture, or afterwards,
and I effect a great saving in weight whilst obviating chemical or electro-chemical
action causing injury to the shafts as aforesaid.
Dated this 15th day of July 1892.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, Agents.
COMPLETE SPECIFICATION.
Improvements in .or connected with Propeller or other Shafts of
Steam Ships.
I, WILLIAM HENRY ELLIS of Atlas Iron & Steel Works, Sheffield in the
County of York, Engineer do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascertained
in and by the following statement:-
It has been found in the working of steam ships that a chemical or electro-
chemical action on the shafting takes place causing injury to the said shafting
by "pitting" it and the object of my invention is to provide improved means for
preventing this injurious action. Shafts for war ships have heretofore had brass
casings or liners" applied to them the said casings or liners being usually of
a thickness of three-eighths to one half of an inch and being shrunk on in lengths.
This operation is always attended with considerable risk of bursting the said
casings or liners and the joints (which are burnt together) frequently give way and
therefore the value of this form of casing or liner is materially diminished.
Shafts for the mercantile marine usually have brass casings or liners shrunk on
at the bearings only, there being at the ends of these casings or liners wrought
iron hoops with putty or gutta percha, or some such substance, between them
and the ends of the casings or liners. so that the places where brass meets steel
are not exposed. This method is also a very imperfect preserver, many shafts so
treated have to be replaced owing to the putty or gutta percha or like substance
between the ends of the liner and wrought iron hoops giving way and the con-
sequent cutting action of the water on the exposed portion of the shaft. According

page_text: to my invention instead of employing the aforesaid devices 1 electrolytically
deposit copper or copper alloy upon the shafts which will prevent the objectionable
chemical or electro-chemical action aforesaid from taking place. A suitable
thickness of such electrolytically deposited metal is one-sixteenth of an inch but I
do not limit myself to that thickness. By this means I avoid all danger of
casings or liners bursting or joints giving way in manufacture or afterwards and
I effect a great saving in weight whilst obviating chemical or electro-chemical
action causing injury to the shafts as aforesaid. The following is a convenient
way of carrying out my invention in practice but I do not limit myself. to. the
precise details which I shall describe.
The shaft to which my invention is to be applied is finished turned in the lathe
except at the ends where any attachments which may be necessary for the coating
process have to be made. The shaft is first dipped in a bath of a hot alkaline
solution such as one of potash for instance in order to cleanse it from any greasy
matter. It is then dipped in a pickling bath, such as one of sulphuric or hydro-
chloric acid of suitable strength, to remove any scale, if the surface be not already
clean and free from rust or the like. After removal from this bath it is carefully
examined and cleaned by scrubbing with scratch brushes or otherwise. When all
particles of sand and scale have been removed it is finally rinsed with clear water
and is then at once subjected to the electro depositing process. This should be
effected in two depositing solutions first an alkaline solution and then an acid
solution because the acid solution if used at first would be liable to injuriously affect
the steel whilst the alkaline solution is not quick enough to render it suitable for
use throughout the whole of the depositing operation. The connections between
the dynamo or source of electricity and the electrodes are made before the immer-
sion of the shaft in the depositing solution so that the electric current takes effect
at once on the work entering the first solution. A suitable current at this stage
is one of 10 to 12 amperes per square foot of cathode surface. Great care is
necessary in examining the work while in this solution, and, after the electric
current has been on a short time, the shaft must be removed and examined to
see that a film of copper or copper alloy has adhered all over the surface of the
part or parts which is, or are, to be covered.
If this is found not to have been properly effected the portions which are not
covered must be again cleaned and the shaft must be again placed in the first or
alkaline depositing solution. Depositing solutions such as are referred to in the
Specification of Letters Patent No. 3773 of 1888 granted to Messrs. Wallace &
Smillie are well adapted for the purposes of my invention but other well known or
suitable methods of effecting electro deposition may be used. After a perfect
coating of copper or copper alloy is found to be deposited on the shaft it is placed
in the second or acid depositing solution and an electric current of about 20 ampéres
per square foot of cathode surface is applied until the desired thickness of copper
or copper alloy has been deposited which can be ascertained by measurement.
The time occupied in depositing copper to the thickness of one sixteenth of an
inch is usually between 30 and 40 hours but alloys of copper will usually take
longer. It is beneficial to rotate the work in the depositing solutions especially in
the acid or quick depositing solution and also for some forms of shafts in the first
or alkaline solution also. It is also desirable to circulate the depositing solutions
to ensure uniform strength throughout the work. A method of rotating and
mounting the shaft which may be employed is shewn by the accompanying drawing
whereon Figure 1 is a longitudinal section and Figure 2 is a transverse section of
the acid depositing tank A being the shaft upon which the copper or copper alloy
is to be deposited the said shaft having a piece Q left on at the collar end the said
piece resting on the roller bearings B at one end and a part R (to be subsequently
screwed for the reception of the propeller nut) at other end resting on the roller
bearings B. The method of rotating the shaft is as follows:-C is a pulley
which is driven from suitable overhead shafting and which drives the bevel wheel D.
gearing with the wheel E which is keyed on to the shaft F driving the bevel

page_text: wheels G and H. The wheel H is keyed onto the same shaft as that on which
one of the friction wheels B (or B¹) is keyed. The shaft F is protected (for
instance by varnish) from the action of the acid solution or it may be coated in the
first or alkaline depositing solution to prevent the acid from attacking the steel.
The wheels G and H, the footstep bearings J and K and the rims and centres of,
the rollers B (or B¹) may be made of phosphor-bronze or other metal not liable to
be attacked by the depositing solution. The aforesaid rotatory motion is shewn
applied to both ends of a propeller shaft, which is desirable with long shafts say
for instance shafts 30 feet long. When the shaft is not very long say when it does
not exceed 15 feet in length, the position of the roller bearings is altered to suit,
and the driving motion need be applied at one end only.
The bearings of the rollers B (or B¹) are carried in phosphor bronze bushes S let
into wood blocks T wedged tightly in position in the tank. The electrodes are
arranged as follows:-LL' are two square steel bars supported upon bearers as
shewn and running the whole length of the tank between the two vertical shafts F.
M M are copper plates joining the bars L L' with the anodes N N'. The distance
of the anodes from the shaft at their nearest points is usually about 2. to 3 inches
but this may be varied according to the class of work under treatment. The
bars L L are both connected to the positive pole of the dynamo or source of
electricity. O is a bar also supported upon the said bearers and connected to the
negative pole of said dynamo or source of electricity and similar in section and
length to the bars L L' and P are the cathodes resting on the top of the shaft A in.
the form of an inverted Y. The number and position of the cathodes may be
varied according to length and shape of the shaft. Great care should be taken
that all the surfaces of these connections be well cleaned and bright to ensure a
good current. Figure 3 is a transverse section of the acid depositing tank shewing
She position of the electrodes L L' and O when drawn back to the sides of the
tank to allow the shaft about to be coated to be placed in position on the roller
bearings B B. After the required thickness of deposit has been applied to the
shaft the portions which act as bearings in the ship are turned up in the lathe and
a casing or liner of hard brass for instance is shrunk on to the surface of the
copper or copper alloy and finished turned on the shaft.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
Propeller or other shafts for steam ships having copper or copper alloy applied
thereto by electro-deposition so as to prevent injurious chemical or electro-chemical
action substantially as herein before described.
Dated this 29th day of March 1893
J. H. JOHNSON & Co.,
Agents.