IMPROVEMENTS IN APPARATUS FOR RAISING SUNKEN BODIES, AND IN THE MODE OF OPERATING THE SAME
Year: 1870

page_text: PROVISIONAL SPECIFICATION left by Alexander Melville Clark at
the Office of the Commissioners of Patents, with his Petition, on
the 18th June 1870.-A communication from abroad by Amédée
Mouillard, of 13, Boulevart St. Martin, Paris.
I, ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, do hereby declare the nature of
the said Invention for "IMPROVEMENTS IN APPARATUS FOR RAISING SUNKEN
BODIES, AND IN THE MODE OF OPERATING THE SAME," to be as follows:-
This Invention relates to an improved mode of raising submerged
bodies by the displacement of water by means of chambers containing
flexible casings filled with air, and also to the improved construction
of said chambers, whereby to ensure the success of the operation, and
more particularly to maintain in a self-acting manner an almost constant
equilibrium between the pressure of the internal gazeous fluid and that
of the external liquid under all conditions and at all points during the
raising operation, whatever may be the depth from which the bodies
are to be lifted. The chambers are first sunk and connected to the
article to be raised and then filled with air, which imparts an ascensional
power equivalent to the weight of water displaced, the whole of which

page_text: power is utilized for raising the article submerged, less that required to
lift the apparatus itself. The chamber may either be formed with a
rigid or flexible casing, and in either case the chamber is constructed
to resist any external or internal pressure to which it may be subjected.
The casing to contain air or other gaseous fluid is also closed to prevent
communication with the surrounding water.
If the chamber be rigid the ascensional power would be obtained by
replacing the liquid contained by a gazeous fluid lighter than the said
liquid. If, on the contrary, the chamber be flexible it would be sunk
in a collapsed form and the ascensional power obtained by introducing
the gazeous fluid, which expands said chamber until the internal
pressure of the gas is, if not greater at least equal to the pressure of the
external liquid, and under these conditions of equilibrium the chamber
is not liable to injury from external pressure. This would be the case
so long as the internal and external pressures neutralize each other, but
while the pressure of the fluid injected is constant that of the surround-
ing liquid is variable, increasing according to the depth of immersion
and decreasing nearer the surface, and by introducing the air at a
pressure, determined by the depth of immersion necessary for raising
the article, the internal and external pressures may be regulated without
risk of bursting the apparatus. Again, as the submerged article being
lifted rises towards the surface the external pressure of liquid will
decrease and the internal pressure of the gazeous fluid being constant
the difference of pressure becomes excessive, and hence there is a liability
of bursting the casing.
The present Invention, as before mentioned, is designed to provide
means for maintaining an equilibrium between the internal and external
pressures under all conditions. The Invention is illustrated in the
accompanying Drawings, Figure 1 of which shows a vertical section of
the improved apparatus collapsed, in which condition it is to be sunk
and attached to the article to be raised. Figure 2 is a vertical section
of the same submerged and inflated in readiness for being raised.
Figure 3 shows an external elevation of the apparatus. The same
letters of reference indicate like parts in all the Figures. The apparatus
consists of an air chamber of flexible or other material having double
sides, the outer skin being spheroidal in form closed at the upper part
and having a large opening at bottom connected to a neck a. The
inner flexible casing B is also spheroidal and concentric with the outer

page_text: casing A. The two skins are united in one towards the upper part by
a seam 6 made air-tight, and they form two chambers, an inner close
chamber C and an outer space D enclosing the first and open at bottom.
E is a tubular connection communicating with chamber C by the
orifice c and with chamber D by the two flexible tubes d, the air being
supplied to said chambers from pipes e, e¹, respectively. The outer
chamber A is enclosed in a network G of sufficient strength to withstand
the pressure in inflating the air chamber, as also to support the load to
be raised. This network is caused to adhere to the outer covering to
protect the same and prevent chafing. The chambers and the flexible
tubing may be composed of any suitable waterproofed fabric, and the
network unites at bottom in a ring, which is provided with a hook I or
other attachment for connection with the article to be raised. The
apparatus is immersed in its collapsed form to the desired depth, as seen
in Figure 1, and then attached to the submerged article, after which
the air is compressed in chamber C, so as to partially expand the same
at a pressure equal to that of the surrounding liquid. The chamber D
also is then filled with compressed air (the water being expelled at
neck a), so as to expand the same, when the apparatus will be inflated
to its fullest extent and possessed of its full ascensional power for
raising the article J attached thereto.
As before mentioned the apparatus in rising passes through water of
decreasing density and the compressed air expands, that contained in D
will not, however, press unduly on casing A, inasmuch as an escape
is provided at orifice a, while the compressed air contained in C will
gradually expand the skin B until it expels all the air contained in D,
bringing the two skins in contact, which mutually support each other
aided by the netting G. Thus the compressed air contained in the
apparatus may expand as the depth and consequently the density
decreases, without the internal pressure of the air exceeding that of the
external water, which would tend to burst the casing.