Improvements in or applicable to Steam Boiler Injectors.
Year: 1898

page_text: Date of Application, 1st Mar., 1898-Accepted, 6th Aug., 1898
COMPLETE SPECIFICATION.
Improvements in or applicable to Steam Boiler Injectors.
I, ENRICO LODETTI, of No. 37, Via della Mercede, Rome, in the Kingdom of
Italy, Mechanic, 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:-
"
My invention relates to a reduction tube for boiler feed injectors for locomotives
and the like which will render this apparatus suitable for use as a pump for the
cleansing and washing of the boiler, or in case of need as a fire pump.
It is well known that the feed apparatus known as an injector" forces water
into the boiler in consequence of the velocity which the steam imparts to the water
in the conical parts of the apparatus. Consequently it is possible to obtain from an
injector a jet of water of suitable speed and range for the purposes above stated.
In carrying the invention into practical effect it is necessary to avoid two draw-
backs:
1. To get rid of the air drawn in by the injector through the overflow, seeing
that this air carried forward by the current of fluid passes out of the nozzle with
considerable noise, and interrupts at intervals the quantity and regularity of the
jet.
2. To control the pressure in the flexible tube between the injector and the nozzle
for the purpose of preventing the said pressure from exceeding the limit suitable
to the resistance and strength of the tube, and thus avoiding any danger to the
operator.
I attain these objects by the application of my reduction tube of which I will
now describe the parts: -
In a reduction tube C are placed the two cones A¹ A" having perforated walls
and directed in the same direction. The first cone is perforated with about 290
holes of a diameter of about 2 m.m. The second cone is perforated with about
190 holes of a diameter of 23 m.m. The total surface of these small holes is almost
equal to the section of the tube C. The présence of these two conical diaphragms
will consequently have no injurious influence upon the range of the water, whilst
the temporary check which the diaphragms oppose to the jet passing from the
conical nozzle of the injector, renders the pressure, and consequently the velocity,
of the liquid more uniform in the tube.
In like manner the air aspirated by the apparatus is broken up and divided into
little bubbles of small diameter, and is moreover distributed in the current of fluid,
thus doing away with the bubbling at the nozzle of the tube.
In the central part of the adjusting piece Z of the cones aforesaid there is formed
a hole of 20 m.m. diameter which serves for the removal of any materials collected
in the cone A¹. There are moreover 18 holes of 5 m.m. diameter which serve in
combination with the aforesaid to form a communication between the internal part
of the adjusting tube of the cones and the annular chamber connected to the reliev-
ing valve and to the manometer. The relieving valve is fixed to the projection I)
of the reduction tube C.

page_text: The parts of this valve are as follows:-
E represents a hollow cylinder in which the covered valve moves, resting nor-
mally upon its seat; a pressure disc F is placed at the base of the said valve and
supports at its centre the rod of the valve; between the valve and the disc Fis
placed a coiled spring G having a screw H which exerts a certain pressure upon
the said disc. Small holes are arranged at I for the discharge of the water passing
through the pressure valve from the tubes. A pressure gauge (not shewn in the
drawing) is attached to the piece E above the valve. The relieving valve is regula-
table as usual in valves of this kind by means of the screw H, so that it will open
only at the desired pressure. Practical experiments have shewn that the most
suitable pressure is about four atmospheres. If the screw H be regulated con-
formably hereto the relieving valve will act only when the pressure exceeds four
atmospheres. The pressure gauge will indicate pressures below four atmospheres
which would otherwise remain unknown to the operator.
The reduction tube C is attached to the injector at L by means of an intermediate
tube M, and the discharge pipe is attached at the point N. The said pipe is prefer-
ably of rubber, and has the discharge nozzle attached to its end. This nozzle may
be of any suitable kind applicable for the use of the boiler or for a fire pump.
An apparatus constructed in the manner above described will act well notwith-
standing variations in the pressure of the boiler which works the injector (from 4
to 9 atmospheres).
For the regularity of the working the pressure gauge should be placed hori-
zontally, and having its face turned downwards towards the operator.
It is of course necessary to maintain in the apparatus the minimum pressure
above stated of at least four atmospheres, because at this pressure the maximum
force of the jet is obtained. For this purpose in order to increase the pressure it
is desirable to proceed little by little, and by means of the valve of the "Fried-
mann injector to admit increased quantities of water to the injector through
the aspirating tube, because as the quantity of water increases the pressure increases
likewise until it reaches the desired four atmospheres.
"
The range of the injector is in direct relation to the pressure in the boiler from
whence the steam is drawn. It is therefore obvious that according to the pressure
in the boiler there will be a difference of range in the apparatus, and a difference of
temperature in the water.
In order to suitably regulate these differences, whilst preserving constant the
pressure in the tubes it is necessary to provide the nozzle with four openings of
various sizes. The diameters most suitable for these apertures are of 9, 10, 11,
12 m.m. respectively.
The apparatus or reduction tube in the form above described is best applied to
"Friedmann "
injectors but it is applicable by means of a little change of adjust-
ment to any kind of injector.
One advantage of this apparatus consists in causing the injector to act as a pump
having a continual pressure jet of water warmed to about 65 degrees.. There is no
danger of damage to the rubber tubes or of injury to the operators.
Having obtained by the above described simple and economical means a supply
of warm water under pressure it can be used successfully for cleansing and washing
out the inside of locomotive boilers and the like. By this means there is avoided
all injurious contraction and expansion of the furnace walls, as well as the damage
to the tube plates, especially in boilers with arched fire boxes which present more
difficulty in getting them cooled to such a point that they can be washed out with
water without danger.
My system enables boilers to be washed immediately after the fire is drawn; two
hours and a half are sufficient for the operation, including the re-filling with water
for recommencing operations, and the raising of steam in the locomotive. The
washing out of the pump can be effected at any convenient point alongside the
line provided that a second locomotive be available to actuate the injector. Finally

page_text: this apparatus may be substituted quickly and efficiently for the ordinary fire
pumps within the range of the railway.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
claim is:-
The abovedescribed improvements in injectors for locomotives and the like, sub-
stantially as and for the purposes described and illustrated in the accompanying
drawings.
Dated this 1st day of March 1898.
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.