Improved Method and Mechanism for Locating Obstructions in Pneumatic or other Tube Systems.
Year: 1898

page_text: Date of Application, 19th Apr., 1898-Accepted, 28th May, 1898
COMPLETE SPECIFICATION.
Improved Method and Mechanism for Locating Obstructions in
Pneumatic or other Tube Systems.
I, BIRNEY CLARK BATCHELLER, of 1518, North Fifteenth Street, Philadelphia, in
the State of Pennsylvania, U.S.A., Mechanical 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, and
accompanying drawings, that is to say:―
My invention relates to a new method for locating obstructions in pneumatic or
other tube systems and to improved mechanism especially adapted for carrying my
mechanism into practical use.
It has heretofore been attempted, with varying degrees of success, to locate
obstructions in long tubes by ascertaining and recording the lapse of time
intervening between the creation of a sound impulse in the tube at a certain point
and the reflection or echo of the said sound returning to the said point after being
reflected from the obstruction in the tube. The velocity of the sound wave being
a known factor it is easy to compute from the data thus obtained the distance of
the obstruction from the point in the tube at which the test is made. My invention
is an improvement upon the method briefly described above, and, in its main
feature, consists in wholly, or partly, closing, the connection from the tube to be
tested to the sound and time recording apparatus at the time when the sound,
impulse is created in the tube, and then fully and freely opening the said connection
before the echo or reflection of the said sound returns to the point in the tube
where the test is made, my purpose being to avoid an undue and disruptive shock
to the recording apparatus, such as would be apt to occur if the recording apparatus
was in full connection with the tube at the time the sound is made, and, at the
same time, to cause the weaker reflected sound to act directly and with full force
upon the recording apparatus.
In carrying my invention into effect I have devised a connection between the
tube and the recording apparatus of such a character, or provided with such
appliances, that it may be partially, or wholly, closed when the impulse is created,
and freely and entirely open before the return of the echo or reflected sound wave.
Another useful and valuable feature of my invention consists in protecting the
diaphragm to which the sound waves are communicated and through which they
are transmitted to the recording mechanism against undue and disruptive shock by
placing in front of it the shield or protecting plate against which it is impelled in
the event of its being exposed to a dangerous sound impulse and by means of
which its outward movement to a disruptive point is prevented.
The nature of my improvements will be best understood as described in
connection with the drawings in which it is illustrated, and in which
Figure 1 is a plan view of the recording apparatus.
Figure 2 a side elevation of the same.
Figure 3 a diagrammatic illustration of the various appliances making up the
recording apparatus and connected therewith and all of the means for connecting
the recording apparatus with the tube and for creating a sound impulse in the

page_text: Figure 4 is an enlarged sectional view of the sound recording diaphragm and its
immediate connections, and
Figure 5 a diagrammatic illustration of the record made by the appliances shown
when in operation.
A is a cylinder having a smooth surface which, in use, is coated with lamp
black, or some other film, upon which a light stylus will make a visible impression.
This cylinder is secured to a shaft B threaded at one end, as indicated at B', and
resting in convenient bearings, as indicated at C and C¹, bearing C being threaded
to engage the threaded portion of the shaft B. D is a crank by which the shaft
and cylinder can be turned and obviously, as they turn they are, by the action of
While I have indicated a
the screw B¹, longitudinally and gradually moved.
crank as
a convenient device for rotating and moving the cylinder it will, of
course, be understood that any convenient driving apparatus may be substituted
therefore. As shown, the cylinder is mounted on a base E, the bearings C and C¹
being supported on standards E³ extending up from the side piece, and other
standards, as indicated at E¹ E2 and E4, being provided as supports for the
appliances hereinafter described. F is a tuning fork of known pitch having a
light stylus, indicated at f, attached to one of its prongs in position to rest lightly
on the cylinder A. The tuning fork, as shown, is attached to a block F¹, hinged to
the standard E, at F2, and adjusting screw F³ serving to adjust the pressure with
which the stylus f will rest against the cylinder A. In practice, I may state I
have used a tuning fork giving the note C of the musical scale and having a
known rate of 512 single vibrations per second. The wave line produced by the
stylus produced by the said tuning fork is diagrammatically illustrated at M. in
Fig. 5, each single vibration thus recorded measuring one five hundred and
twelfth (512) of a second.
it.
G is a light rod pivotally supported on a block G9, hinged at G10 to the
standard E, and adjustable in height by means of the adjusting screw g². An
extension G2 having a turned up and slotted end G+ serves to support the outer end
of the light lever or rod G to which is attached the stylus g, the said rod or lever
being pivoted at G¹ to the block G. A spring G2, acting on the lever G, draws
it away from an electro-magnet indicated at G5, said electro-magnet, when
energised, overcoming the tension of the spring and drawing the lever G toward
The energising of the magnet is conveniently effected at definite time intervals,
as indicated in Fig. 3, Go indicating circuit wires in which is situated a battery G
and a pendulum or equivalent escapement, indicated at Gs, and by means of
which the circuit is closed at definite time intervals, for instance, I have found it
convenient to use a pendulum of such length that the circuit will be closed once
in each half second, and the record upon the cylinder A effected by the stylus g
will be of a character indicated at L in Fig. 5, such a record serving, in connection
with the tuning fork record M, to greatly facilitate the computation of the total
time interval.
The sound impulse recording mechanism operates a light pivot lever H having at
its end a stylus h. This lever, as shown, is pivoted to a frame H2 supported on the
standard E2, the pivot being indicated at H³, a light spring H³ acting to press the
lever H in one direction, as shown in Figs. 1 and 4, and an adjusting screw H³
being provided as an abutment to prevent the movement of the lever H against the
spring beyond a definite point. The lever is actuated by a connection H7 connected
also to a diaphragm Ho which is secured to a block H hollowed out to form a
chamber H5 into which opens a passage ht or rather a tubular connection H¹¹
screwing into the passage h¹. The tubular connection H" is in turn connected with
the tube to be tested, conveniently, as shown, by a flexible pipe H12 opening through
a block I having a funnel shaped internal opening 1' into a pipe section J which as
shown is connected with the tube O to be tested and is formed with an opening J¹
through which a pistol barrel can be inserted, K, Fig. 3, indicating the pistol in
position to be fired.
It will be understood that an important feature of my method and also of my

page_text: apparatus is the provision of means whereby the tubular connection between the
tube to be tested and the sound recording apparatus can be partly closed. Any
convenient device may be employed for this purpose, and among them a cock H¹³,
Fig. 3, which is a ready and simple means of partly closing and quickly opening
the flexible tube H12.
In order to further protect the diaphragm H against disruptive sound waves I
employ a shield or protecting plate H placed in front of it at a distance which will
perimit of its normal vibration but which, in case of an impulse adapted to have a
disruptive effect upon the diaphragm, will arrest the motion of the diaphragmn and
prevent its being forced out beyond a safe limit.
The character of the record made by the stylus h is indicated at N in Fig. 5, n¹
indicating the record made at the time the pistol is fired and n² the record made on
the return of the echo or reflected wave.
The operation of my device will be readily understood from what has already
been said. When a test is to be made the time recording apparatus is set in
operation, as is also the cylinder A, with the effect of making a record such as M,
or, preferably, such as M and L; the operator then partially closes the cock H¹³
and fires the pistol K into the pipe section J, as a result of which a sound wave is
transmitted through the partially closed connection to the diaphragm H and by it,
through the mechanism described, to the stylush which makes a record, as indicated
at n¹. The operator then fully opens the cock H¹³ and upon the return of the echo
or reflected sound, which is of course much weaker than the initial sound, its
impulso passes freely through the connection to the sound recording apparatus, the
stylush making a record of the return of the sound, as indicated at n². The work
of calculating the distance of the obstruction against which the sound has been
reflected is then simply the co-ordinated records enabling the operator to ascertain
within a very short distance the exact position of the obstruction.
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 of locating obstructions in tubes which consists in connecting.
the tube to be tested with an apparatus for recording time intervals and sound
waves created in the tube, making a loud noise,- -as by an explosion,-in the part
of the tube to which the recording apparatus is attached, partly closing the
connection from the tube to the recording apparatus prior to the making of said
loud noise therein so as to avoid an undue strain on the recording apparatus, and
immediately opening said connection after the sound impulse is created in the tube
so as to afford a free passage to the recording apparatus for the sound impulse
reflected from the obstruction in the tube.
2. In an apparatus for locating obstructions in tubes,-the combination with an
apparatus for visually recording time intervals of means for co-ordinately
recording sound waves said means being connected with the tube to be tested, as
described, and so that sound waves created in said tube will be visually recorded,
and means for wholly or partially interrupting the transmission of the sound waves
from the tube to the sound recording device.
3. In an apparatus for locating obstructions in tubes consisting of a device for
visually recording time intervals and means for co-ordinately recording sound
impulses created in the tube to be tested, the combination of a tubular connection
leading from the tube to be tested, a diaphragm open to sound impulses coming
through said connection, a stylus actuated by said diaphragm to record the sound
impulses, and means for varying the opening through the tubular connection to the
diaphragm.
4. In an apparatus for locating obstructions in tubes consisting of a device for
visually recording time intervals and means for co-ordinately recording sound
impulses created in the tube to be tested, the combination of a tubular connection

page_text: leading from the tube to be tested, a diaphragm open to sound impulses coming
through said connection, a stylus actuated by said diaphragm to record the sound
impulses and a guard plate situated in front of the diaphragm arranged to check
its outward movement beyond a point of safety.
Dated this 19th day of April 1898.
EDWARDS & Co.,
65 and 66, Chancery Lane, London, Agents for the Applicant.