A METHOD OF GAUGING THE LENGTH OF AIR PIPE CONNECTED THROUGHOUT A RAILWAY TRAIN, AND APPARATUS FOR THAT PURPOSE
Year: 1884

page_text: I, ALBERTUS PHILIPPUS KAPTEYN, of the Westinghouse Brake Company Limited,
Canal Road, King's Cross in the County of Middlesex Engineer, do hereby declare
the nature of my invention for "A METHOD OF GAUGING THE LENGTH OF AIR
PIPE CONNECTED THROUGHOUT A RAILWAY TRAIN, AND APPARATUS FOR THAT
PURPOSE" to be as follows:
།
The pipes used on railway trains, for communicating fluid pressure to work
brakes or signals, are usually provided at each end of each carriage with stopcocks
which are closed when the pipes are uncoupled. Sometimes, instead of employing
such stopcocks, the couplings which connect the pipes are provided with valves
which automatically close when the couplings are disconnected. It may happen
that, when the pipes are coupled, a stopcock is left closed, or the connection of a
coupling between some two of the carriages may have been omitted, or, generally,
the communicating pipe may at some part of the length be so obstructed that the
necessary communication through it is interrupted.
My invention relates to a method of and apparatus for ascertaining the existence
and position of such an interruption, so that the engine driver, without leaving his
place on the locomotive, can at once detect the fact of the interruption of the
communication, and ascertain approximately on which carriage or between which
two carriages of the train the interruption exists. The method which I adopt for
this purpose is the following.
Knowing approximately the cubic contents of a certain length of communicating
pipe, I provide means of gauging by reduction or increase of pressure in the pipe
the length of it that is unobstructed. If, for instance, the pipe contain air at a
pressure exceeding that of the atmosphere, I allow some of the air to escape from
the pipe, so as to reduce the pressure in it by a known amount, and I measure the
quantity thus escaping by collecting in a reservoir, by measuring its current, or by
timing its outflow through a certain orifice. Or, if the pressure in the pipe is
below that of the atmosphere, I admit into the pipe such quantity of air as will
raise the pressure by a given amount. In either case the measured quantity of air
is approximately proportional to the length of unobstructed pipe, from or into
which it flows.

page_text: Apparatus for thus gauging the length of unobstructed pipe may be arranged in
various ways, all however based on the method stated above. A convenient forin
is as follows
On the locomotive I provide a small reservoir of known capacity furnished with
a pressure gauge, and a valve by which the train pipe can, on opening a stopcock,
be made to communicate with the reservoir, the valve being adjusted so as to close
automatically when the pressure in the pipe is changed by a certain amount. The
pressure gauge, then, by shewing the change of pressure produced in the reservoir,
indicates the length of pipe from or into which air of the reservoir had flowed.
It is convenient to mark the pressure gauge with graduations corresponding with
the average length of pipe on each carriage, so that its index shews at sight the
number of carriages that are in unobstructed communication with the reservoir.
Obviously the self closing valve above mentioned might be dispensed with, the
cock being closed by hand when the pressure in the train pipe is changed to the
desired extent.
Instead of employing a reservoir as above described, the current of air passing
from or into the train pipe, to make a given change of pressure therein, may be
arranged to act on a light fan wheel causing it to revolve. The number of
revolutions shewn by an index, worked by reducing gear from the fan, will then,
as before approximately indicate the length of pipe in which the change of pressure
takes place. Again there may be a small orifice by which air can pass from or into
the train pipe, and the time occupied in producing a certain change of pressure
will be approximately proportional to the length of pipe in which the change takes
place. This time may be noted by an ordinary watch or clock. I prefer, however,
to arrange a special clock-work which is started by the act of opening the orifice
and stopped by the closing of the orifice by hand or by the automatic closing of the
valve which takes place when a known change of pressure is effected. The hand
of the clock will in that time have moved over an arc of dial approximately
proportional to the length of pipe dealt with, and in this case also the dial may
have graduations corresponding with successive carriage lengths.
DAL!
T
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.

page_text: I Albertus PhiLIPPUS KAPTEYN of The Westinghouse Brake Company Limited,
Canal Road, King's Cross in the County of Middlesex, Engineer, do hereby declare
the nature of my invention for "A METHOD OF Gauging the LENGTH OF AIR
PIPE CONNECTED THROUGHOUT A RAILWAY TRAIN, AND APPARATUS FOR THAT
PURPOSE" and in what manner the same is to be performed to be particularly
described and ascertained in and by the following statement:-
The pipes used on railway trains for communicating fluid pressure to work
brakes or signals, are usually provided at each end of each carriage with stop cocks
which are closed when the pipes are uncoupled. Sometimes, instead of employing
such stopcocks, the couplings which connect the pipes are provided with valves
which automatically close when the couplings are disconnected. It may happen
that when the pipes are coupled, a stop cock is left closed or the connection of a
coupling between some two of the carriages may have been omitted, or generally
the communicating pipe may at some part of the length be so obstructed that the
necessary communication through it is interrupted.
My invention relates to a method of and apparatus for ascertaining the existence
and position of such an interruption, so that the engine driver, without leaving his
place on the locomotive, can at once detect the fact of the interruption of the
communication, and ascertain approximately the number of carriages which are in
uninterrupted communication with the engine. The method which I adopt for
this purpose is the following.
Knowing approximately the cubic contents of a certain length of communicating
pipe, I provide means of gauging by reduction or increase of pressure in the pipe
the length of it that is unobstructed. If, for instance, the pipe contain air at a
pressure exceeding that of the atmosphere, I allow some of the air to escape from
the pipe so as to reduce the pressure in it by a known amount, and I measure the
quantity thus escaping by collecting the whole or a certain proportion thereof in a
reservoir, or by measuring its current. Or, if the pressure in the pipe is below
that of the atmosphere, I admit into the pipe such quantity of air as will raise the
pressure by a given amount. In either case the measured quantity of air is
approximately proportional to the length of unobstructed pipe, from or into which
it flows.
Apparatus for thus gauging the length of unobstructed pipe may be arranged
in various ways, all however based on the employment, firstly, of valve apparatus
by which a definite reduction or increase is made in the brake pipe pressure, such
valve being either automatic or worked by hand, and secondly of means for
measuring the whole or a part of the air that has passed out of or into the brake
pipe in effecting such change of pressure.

page_text: One arrangement of apparatus for this purpose, adapted for train pipes charged
with air at a pressure above that of the atmosphere, is shewn at Figs 1 to 5 of the
accompanying drawings. Fig. 1 shews a vertical section, Fig. 2 a plan, Fig. 2ª an
end view of the socket, Fig. 3 a section on line X X Fig. 1, and Figs. 4 and 5
sections taken respectively on lines Y Y and Z Z Fig. 3.
The apparatus consists of an automatic valve box A. A¹ arranged to close the
communication with the train pipe as soon as the required reduction of pressure is
effected, a stop cock B by which the apparatus is brought into or thrown out of
action, a tubular reservoir of known capacity and a pressure gauge D indicating
the pressure in the reservoir.
In the valve box there is a flexible diaphragm a fixed between the two compart-
ments A A¹, the centre of the diaphragm being connected to a guiding stem, round
which is a helical spring a² pressing against adjustable collars a³ on the stem, so as
to tend to hold the diaphragm in the raised position, and thus holding open a
valve a attached to its under side. The valve box is connected at A³ to the train
pipe, so that air pressure passes from the latter through the passage a¹ into the
compartment A¹
When the stop cock B is in the normal position, shewn on the drawing, in which
it closes the communication between the valve box and the reservoir C, it establishes
by means of its passage b a communication between the compartments A. and A¹
by means of the passages a³ and a6, so that the air pressure existing in A¹ will also
be transmitted to A, and the diaphragin a being thus subjected to the same
pressure on both sides, the valve a¹ will be kept open by the spring a².
If now the cock B be turned 90° to the right, it closes the passage as leading
into compartment A, and, by means of its passage bit establishes a communication
by the passages a³ and a' between the compartment A' and the reservoir C, so that
air pressure will now pass froin the train pipe through the compartment A¹ into
the reservoir, thus reducing the pressure in the former and raising it in the latter.
As the air confined in the chamber A is at a pressure equal to that originally
existing in the train pipe, it follows that so soon as the pressure in the train pipe
and in A¹ is reduced below that in A to such an extent as to overbalance the
upward pressure of the spring a³, the valve a¹ will be closed down upon its seat S
by the pressure above the diaphragm, and no further escape of air will take place.
If the apparatus is intended to measure the whole of the air which has thus
escaped from the train pipe, then the passage a' is connected directly to a reservoir
of convenient size, so that the air contained therein will be raised to a certain
pressure by the entrance of the air from the train pipe, and as this rise in pressure
will be proportionate to the quantity of the entering air, it will also correspond
to the length of train pipe from which this air has escaped; that is to say, the
longer the train pipe, the greater will be the quantity of escaping air and conse-
quently also the greater the rise in pressure in the reservoir. A pressure gauge D
placed upon the reservoir will therefore give. a means of estimating the length of
train pipe operated upon. Thus if the dial of the pressure gauge be marked with
divisions representing lengths of carriages, and the rise of pressure in the reservoir
be such as to cause the index to point at 5, the operator would at once understand
that the train pipe was completely coupled up and clear throughout the length of
5 carriages, and if the train consisted of more than carriages, the above indication
would shew that there was an obstruction or interruption in the pipe at or about
the fifth carriage.
In order to reduce the size of the reservoir C for the sake of convenience, it is
preferred to measure only a part of the air which has escaped through the automatic
valve.
For this purpose the passage a' is made to communicate with the outer air by a
passage a, Fig. 3, so that the greater portion of the air passing from the train pipe
will escape into the atmosphere, but at the same time the air pressure in a' is made
to raise a small diaphragm d against the action of a spring e thus uncovering a

page_text: passage a, by which consequently a certain portion of the air pressure will pass
into nipple E and thence into the reservoir C through a small hole a¹º formed in a
plug P. The hole a being very small, a fine wire gauze or other screen p is
provided above it to prevent it from being obstructed with dirt &c. The reservoir C
is conveniently made in the form of a tube of any desired length, to the end of
which the pressure gauge is attached.
As the air pressure entering the reservoir will be in definite proportion to that
escaping through the passage a³, it will be seen that the rise in pressure in C, and
consequently the indications on the gauge will always be in definite proportion to
the total volume of escaping air, and hence give a means of estimating the length
of pipe operated upon.
As soon as the automatic valve closes, consequent upon the desired reduction in
pressure having been reached, the air pressure in the passages a7 and a³ and also in
the cavity under the diaphragm d will fall to that of the atmosphere, whereupon
the spring e will force down the diaphragm so as to close the passage a and thus
prevent the escape of air pressure from the reservoir C, whereby the pressure gauge
will be maintained at its indication so that this can be conveniently read and
noted.
The observation having been completed, the cock B is turned back to its original
position, in which a second passage 61 therein will establish a communication
between the nipple E and reservoir C and the atmosphere by means of a passage b³
as at Fig. 5 so that the air pressure can now escape and the index of the gauge
return to zero. At the same time also the passage b of the cock will re-establish
the communication between the two compartments A. and A' thus equalising the
pressure in both, and causing the valve a¹ to be raised off its seat again.
It will be evident that instead of obtaining the indications by means of
measuring the quantity of air which is forced through a small opening, an
indication for the same purpose might be obtained by causing the escaping air to
force a liquid through a small opening so as to indicate its quantity (the quantity
of escaping air) by the rise of a column of such liquid in a graduated tube.
Figs. 6 to 10 shew such an arrangement of such an apparatus. Fig. 6 shews a
vertical section of the automatic valve apparatus. Fig. 7 shews a vertical section
of the measuring apparatus. Fig. 8 shews a sectional plan on line XX. Fig. 9
shews an end elevation, and Fig. 10 shews a section on line Y Y.
The automatic valve apparatus A. A' is similar in its construction and operation
to that previously described; the air pressure passing from the train pipe mostly
escapes into the atmosphere through the passage a³ in the nipple E; a small portion
thereof passes through the passage a³ into a chamber F containing a fluid such as
mercury. This chamber communicates by passages all o, and a¹0 with the interior
of the glass tube G provided with a scale H having divisions indicating carriage
lengths. Thus on the air pressure entering the chamber F the liquid will be forced
thereby through the passages a¹¹o and the small opening a" into the tube G, in
which it will stand in a greater or less height, according to the quantity of air
forced into the chamber F. Below the passage o is a diaphragm valve d pressed
upward by a spring e acting on a plate K so that as soon as the air pressure
ceases to act upon the liquid in F in consequence of the valve A having closed the
escape, the spring e causes the diaphragm to close the passage o, and thus retains
the liquid column in the tube G to enable the observation to be made. In order
to allow the liquid to pass back into the chamber F again after the observation
has been completed, a stem on the plate K is provided with an eccentric I having a
handle by which it can be turned into the position shewn on the drawing, in which
it draws down the plate, against the action of the spring, thus allowing the
diaphragm d to move away from the aperture of the passage. On pressure being
again admitted into F, the liquid will force the diaphragm and plate downward
sufficiently to release the eccentric, when the handle in dropping will turn it into
the position to which it will again allow the spring to force the diaphragm against

page_text: the opening of o as soon as the escape of air pressure is again stopped. The
quantity of mercury which flows through the small opening a10 is not the same for
each unit of train pipe, but decreases somewhat in proportion to the number of
units. In order to avoid unequal divisions on the scale which would result from
this, a rod R of varying diameter is introduced into the tube so as to reduce the
sectional area of the tube in the same proportion as the decrease in quantity of the
inflowing mercury, and thus allow of uniform divisions on the scale.
W is an overflow chamber to prevent the waste of mercury in case the indicator
should be used at a time when the supply of air pressure to the train pipe is not
cut off.
Instead of estimating the quantity of air escaping from the train pipe by means
of a gauge or mercury column, this quantity may be approximately measured by
arranging the current of its flow so as to give rotation to a wheel and counting the
number of revolutions of the wheel corresponding to a known or definite change of
pressure in the train pipe. Fig. 12 shews a front view partly in section and Fig. 13
shews a transverse section of a gauge K arranged to operate in this manner.
A nozzle E by which air escapes either directly from the train pipe on opening a
cock or valve, or from the automatic valve apparatus described, is so placed as to
direct the current against the blades or vanes of a lightly pivotted wind wheel k,
which is connected by suitable reducing gear to an index ¹ that shews the
number of revolutions of the wheel.
The number of revolutions thus indicated being that due to the quantity of air
escaping in order to make a certain reduction of pressure in the train pipe, is
approximately proportional to the capacity or length of train pipe from which the
air flows.
The above described several apparatus are also applicable with slight modifications,
for gauging train pipes in which the air pressure is less than that of the atmosphere;
Fig. 11 shews a section of the modified automatic valve apparatus for this purpose.
In this case, the brake pipe connected at A2, being, as before, in communication
with the compartment A¹, the diaphragm a and valve a¹ are pressed downwards by
the spring a for keeping the valve open.
The cock B, as before, alternately establishes a communication between the
compartments A and A¹ and between A¹ and the branch a' leading to the indicator,
so that when it is in the position shewn both sides of the diaphragm are subject, to
the partial vacuum existing in the train pipe, and when the cock is turned into the
other position, air passes from the reservoir of the indicator through compartment A¹
into the train pipe until the pressure in the latter and in A¹ has risen to such an
extent as to overbalance the downward pressure of the spring a², whereupon the
valve a¹ will close and prevent the further ingress of air. The gauge D would in
this case be arranged as a vacuum gauge, or, in the case of the liquid indicator, the
liquid would be made to indicate by its descent in a tube arranged below the level
of the chamber F instead of by its ascent.
It will be seen that when the above described train pipe indicator is applied to
automatic brake apparatus, in which any escape or ingress of air pressure from or
into the train pipe causes the brakes to be applied, this will take place when the
indicator is used, and as, owing to the gradual and regulated escape of air pressure
effected by the use of the apparatus, the brakes are applied in a very uniform and
perfect manner, the automatic valve apparatus may with advantage be used for
applying the brakes independently of its use as a train pipe indicator.
It will be evident that in all the above arrangements, instead of employing the
automatic valve apparatus for effecting the reduction or increase of pressure in the
train pipe by a definite amount, an ordinary stop cock turned by hand might be
used in combination with a pressure gauge upon the train pipe, whereby the
operator will be enabled to allow of the escape of air until the desired change in
pressure has been effected. It is preferred however to employ the automatic valve
apparatus for this purpose,

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The method substantially as herein described of ascertaining the length of
unobstructed train pipe by measuring the whole or a portion of the quantity of air
necessary to make a given change of pressure in it.
2. The use of apparatus for ascertaining the length of unobstructed train pipe
consisting of valve apparatus by means of which a certain reduction or increase of
pressure is effected in the train pipe and of apparatus for measuring the whole or
part of the air which has escaped from or entered the train pipe in effecting such
reduction.
3. The use in combination with a train pipe of valve apparatus so arranged as
to close automatically when, by the passage of air through it, the pressure in the
train pipe has been increased or decreased by a definite amount substantially as
herein described,
4. The use of apparatus for ascertaining the length of unobstructed train pipe
consisting of a nozzle through which the air is allowed to flow from or into the train
pipe until a certain change of pressure is effected therein, operating in combination
with a wind wheel and counter whereby an indication of the quantity of air
flowing through the nozzle is obtained, substantially as herein described.
..ני
L1
T
ABEL & IMRAY,
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.