Improvements in Apparatus or Appliances for the Collection and Recording of Sound Transmitted Through Water.
Year: 1889

page_text: Date of Application, 26th Mar., 1889
Complete Specification Left, 24th Dec., 1889-Accepted, 1st Mar., 1890
PROVISIONAL SPECIFICATION.
Improvements in Apparatus or Appliances for the Collection and
Recording of Sound Transmitted Through Water.
I, WALTER WALKER, of 69 Chancery Lane, in the County of Middlesex, Electrical
Engineer, do hereby declare the nature of this invention to be as follows:-
In electric telephonic or like apparatus or appliances as now constructed and
employed for the collection and recording of sound transmitted through water, such
as between ships or between ships and forts, or pier heads, or vice versa, or between
other fixed and moveable structures separated by water, there is little reliance to be
placed on such apparatus or appliances as, owing to the close proximity at which it is
necessary to arrange the contact points or screws, (or other means employed) to the
diaphragms or collecting instruments so as to make a contact by the action of sound-
waves produced upon such diaphragms or collecting instruments, it frequently occurs
that when a ship, lurches, pitches, rolls, tosses, or falls lower in the water, than during
a calm, the density of the water at such lower depth causes increased pressure upon
the diaphragmns or collecting instruments which coming against the contact points or
screws (or other means employed) makes a contact and thus actuates the recording
instruments. It will thus readily be seen that it would be impossible to tell whether
the contact had been made and the recording instruments actuated by a sound-wayo,
or by pressure caused by the increased density of the water on movement of the ship,
and therefore one could never say whether it was the approach of a ship, or the rolling
of one's own vessel which was indicated on the recording instruments.
Now, the object of my Invention is to remedy this defect by so constructing these
apparatus or appliances that any pressure caused by the increased density of the
water, below the water line, at which the apparatus or appliances are placed so as to
roceive or collect the sound-waves shall have no effect upon such apparatus or appliances.
For this purpose, the telephonic or other like apparatus or appliance is enclosed
within a water-tight box or chamber which is provided, say at bottom, with a tube
entering the water, and of sufficient length to prevent the water passing into the box
or chamber. This tube has an internal area arranged to correspond to that of the
diaphragms, or sound collecting instruments, in such a manner that any increased
pressure exerted on the diaphragms, or sound collecting instruments in front, by the
descent, or other movement, of the ship in the water, will be counteracted exactly in
the same ratio by the pressure of air in the tube and at the back of the diaphragms or
sound collecting instruments. Or, in other words, the external and internal pressures
on the diaphragms or sound collecting instruments will be neutralized or equalized at
every movement of the ship, and the result will be that the diaphragms or sound
collecting instruments, will be maintained in equilibrium and only be acted upon by
the sound-waves.
By preference, I construct the diaphragms or sound collecting instruments, of very
thin plates of aluminium, or of platinum, so sensitive as to be acted upon by sound-
waves proceeding from many miles.
Doted this 26th day of winTCH 1809.
ERNEST DE PASS,
68, Fleet Street, London, Agent for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Apparatus or Appliances for the Collection and
Recording of Sound Transmitted Through Water.
I, WALTER WALKER, of 69 Chancery Lane in the County of Middlesex, Electrica
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, reference being had to the accompanying drawings and to
the letters and figures marked thereon, that is to say :-
In electric telephonic or like apparatus or appliances, as now constructed, and
employed for the collection and recording of sound transmitted through water, such
as between ships, or between ships and forts, or pier heads, or vice versa. or between
other fixed and movable structures separated by water, there is little reliance to be
placed on such apparatus or appliances, as, owing to the close proximity at which it
is necessary to arrange the contact points or screws, or other means employed, to the
diaphragms or collecting instruments so as to make a contact by the action of sound-
waves produced upon such diaphragms or collecting instruments, it frequently occurs
that when a ship lurches, pitches, rolls, tosses, or falls lower in the water than during a
calm, the density of the water at such lower depth causes increased pressure upon the
diaphragms or collecting instruments which, coming against the contact points or screws,
or other means employed, makes a contact and thus actuates the recording instruments.
It will thus readily be seen that it would be impossible to tell whether the contact
had been made and the recording instruments actuated by a sound wave, or by pressure
caused by the increased density of the water on movement of the ship, and therefore
one could never say whether it was the approach of a ship, or the rolling of one's own
vessel which was indicated on the recording instruments.
Now the object of my invention is to remedy this defect by so constructing these
apparatus or appliances that any pressure caused by the increased density of the water,
below the water line, at which the apparatus or appliances are placed so as to receive
or collect the sound waves, shall have no effect upon such apparatus or appliances.
Although in my Provisional Specification I described the use of a water-tight box
in which the telephonic apparatus was to be enclosed, I have since discovered, owing
to numerous experiments instituted, that I can dispense with the use of such box
without in anywise affecting the nature of the invention, and connect the dipping tube
directly to the telephonic apparatus itself.
In order that my said invention may be fully understood and readily carried
into effect, I will proceed in describe the same with reference to the drawings here-
unto annexed.
Fig. 1 is a front elevation, and Fig. 2 is a vertical section shewing one construction
of my apparatus. a is the diaphragm of the telephonic receiver provided with a
platinum contact a¹ is an adjustable contact screw working in a stuffing-box c.
The space behind the diaphragm forms a watertight chamber d to which is connected
a dip tube e. The internal diameter of this tube is so calculated as to correspond with
the cubic capacity of the chamber d; so that any deviation in the pressure acting on
said diaphragm will be counteracted exactly in the same ratio by the air contained in
the dip tube e and chamber d, so that the external and internal pressures acting on
the diaphragm will be equalized. Hence, in the case of a ship, at every movement
thereof, the diaphragm will always be kept in equilibrium and can only be affected by
the sound waves travelling through the water.
Fig. 3 is a front elevation and Fig. 4 is a vertical section shewing a modified con-
straction of my apparatus in which the same principle is carried out.
The telephonic receiver is here provided with lugs a² for securing
within a cylindrical cup f. This cylindrical cup communicates, by means of a circular
concentrically
passage with a closed tube or chamber situated above it. This circular passage
is so located that the uppermost point in its circumference is on the axial line of the
cup as shewn in fig. 3. Passing through said closed tube or chamber is an air tube

page_text: having an orifice g¹ placed as near as possible to the top of the tube or chamber ƒ³.
One extremity of this air tube g leads to the chamber d of the telephonic receiver, and
the other extremity may be led to a pressure gauge situated on board the ship (or
other structure) to which the apparatus is affixed, so that the pressure in the chamber d
may be readily and accurately ascertained. is the space through which the water
enters to the chamber. The apparatus, when in use, is affixed to the ship (or other
structure) below the water level by means of screws passing through the lugs. It
is to be clearly understood that the area of the space h which is open to the entrance
of the water, must be equal to the area of the diaphragm a of the telephonic receiver,
also that the internal diameter of the tube or chamber is so calculated as to
correspond with the cubic capacities of the chamber d, and air tube 9.
The action of the apparatus is as follows: Assuming the same to be applied to a
ship, any alteration that takes place in the position or motion thereof will cause a
difference in the external pressure acting upon the diaphragm a, which is counter-
halanced internally by the pressure of air in the chamber d and tube y caused by the
water rising in the chamber f2 in proportion to the depth to which the instrument is
immersed. This compensation takes place each time the apparatus is raised or
lowered by the motion of the ship in the water and insures only the sound waves
affecting the diaphragm. The area of the space through which the water enters to
the chamber being equal to the area of the diaphragm a, an equal pressure acts
upon each when the instrument is so placed as to receive the full force of the water
through which it is passing, or which is passing it; by this arrangement the
equilibrium of the diaphragm is maintained.
By preference I construct the diaphragms, or sound collecting instruments, of very
thin plates of aluminium, platinum, or silver, so sensitive as to be acted upon by sound
waves proceeding from many miles.
When the apparatus is applied to forts or pierheads, or other fixed structures, the
difference of pressure resulting from the alteration of the water level will be com-
pensated in a similar manner to that above described in connection with ships.
Having now particularly described and ascertained the nature of my inven-
tion, and in what manner the same is to be performed, I claim:
1. The combination, with a telephonic or like receiving instrument for the collection
and recording of sound transmitted through water, of a compensating appliance or
apparatus so constructed that the external and internal pressures acting on the
diaphragm of such receiving instrument will be equalized and the diaphragm thereby
maintained in perfect equilibrium, substantially as set forth.
2. The construction and use of the compensating appliance or apparatus herein
described and shewn with reference to Figs. 1 and 2 of the accompanying drawings,
and for the purpose set forth.
3. The construction and use of the modified arrangement of compensating appliance
or apparatas, as herein described and shewn with reference to Figs. 3 and 4 of the
accompanying drawings, and for the purpose set forth.
Dated : 514 1 of 1)
1000
ERNEST DE PASS,
68, Fleet Street, London, Agent for the Applicant.