US3195493A - Submarine machines - Google Patents

Description

July Z0, 1965 A, LACAM ETAL SUBMARINE MACHINES Filed April 2 1963 all United States Patent O 3,195,493 SUBMARNE MACHINES Andr Lac-am, Chaville, and Boris Vodar, Paris, France,

assignors to Centre National de la Recherche Scientiique, Paris, France, a French government administration Filed Apr. 2, 1963, Ser. No. 269,939 Claims priority, application France, Apr. 4, 1962, 393,317 7 Claims. (Cl. 114-16) The present invention relates to submarine machines i.e. to machines immersed in water.

We will rst remind some data relative to the problems of machines intended to be used under water. Such machines generally consist of two portions having distinct functions, to wit on the one hand the cabin for the crew and the control means, the inside of this cabin being kept at atmospheric pressure whatever be the external hydrostatic pressure (the walls of this cabin are therefore suiciently thick to be able to resist the action of compression forces from the surrounding medium rso that, in most cases, the apparent density of this portion is much higher than that of water) and7 on the other hand, a float divided into compartments intended to work as water ballasts and to compensate for the excess of weight of the lirst portion. This result is obtained by lling said compartments with a body or bodies of a density lower than that of water. Gases and liquids are mostly utilized to constitu-te said bodies. However, the use of such uids involves conditions corresponding essentially to their physical behaviour. As a matter of fact, these lift producing iluids are, as a rule, generally more compressible than water. Consequently when the machine sinks deeper and deeper into water, the volume of a given mass of such a fluid decreases more than that of the same mass of water considered at the same depth. The result is an apparent increase of the weight of the machine due to a reduction of the archimedean thrust. In known submarine machines intended to work at great depth, this phenomenon is compensated for in various manners. In bathyscaphes, ballast 'is released as the depth increases. Without this reduction of weight, the machine would move downwardly with a uniformly accelerated movement which would be braked only by friction forces. In so. called Aquarius apparatus, which use a gas as sustaining duid, the gaseous volume is kept substantially constant by constantly adding further gaseous masses. Considering either of these apparatus in equilibrium in water, at a given depth, any displacement from the position of equilibrium will tend to become greater and greater. In other words the equilibrium is unstable.

The object of the present invention -is to obviate these drawbacks and to provide a machine of the above mentioned type which is kept in stable equilibrium without making use of any external force.

For this purpose, the upward force [is obtained at least partly by means of bodies in the solid state, the specific mass and compressibility of which are lower than the respective specific mass and compressibility of the surrounding liquid medium, i.e. water.

It can be shown that, in this case, the equilibrium of the machine is stable. This can be easily understood by supposing that the compressibility of the sustaining bodies -is negligible. From the point of view of the actions exerted thereon, the machine in equilibrium in the liquid is then equivalent to an equal volume of the liquid presen-t inthe zone occupied by the machine and this zone is located between a denser zone located below it and a lighter zone located above it. If, for instance, the machine is moved upwardly into the upper zone, its weight becomes ice higher than the thrust acting thereon and the result tends to bring it back into its initial position. A similar reresult would be produced if the machine were moved into the lower zone.

The machine according to this invention may have the following characteristics, taken either separately or in different combinations:

(a) The sustaining bodies are non porous solids or solids provided with small holes therein, without communication between these holes, the solubility of said solids in water being negligible;

(b) The sustaining bodies are solids coated with a suitable substance which may be varnish, paint, or a metal coating, or disposed in a sheath of thin plastic material, in order to prevent direct contact with the surrounding liquid, i.e. water;

(c) The sustaining bodies are fluidtight hollow solids containing a iiuid, and more especially a gas, under pressure;

(d) The sustaining bodies are hollow solids having hooped walls.

The arrangements mentioned at (c) and (d) are intended to improve, by hooping or by production of an internal counter-pressure, the resistance of the hollow bodies to the external hydrostatic pressure.

It is known that there are many substances that can be used for making at an acceptable price sustaining bodies' corresponding to the above characteristics.

By way of non limitative example we may cite long chain saturated hydrocarbons and some of their acids, nitriles and ketones. One of the most known of these is stearic acid. However this substance i-s not the most favorable because it is very slightly soluble in water. Furthermore its density is relatively high, being 0.847. On the contrary the corresponding saturated hydrocarbon, octodecane, is not soluble in water and its density is only 0.7768. Triphenylamine, of a density of 0.774, can also be used.

The use of hollow or alveolar bodies makes it possible to obtain, from heavy materials such as metals, sustaining bodies of very low apparent density. Of course the mechanical properties of the material forming the walls of said bodies must be suicient to enable the recesses both to resist the compression and to have walls thin enough to permit of obtaining a low density. This last condition therefore implies a maximum rate of lling of the recesses. This rate may be determined in the following manner; if d is the density of the surrounding liquid mediurn (water) and D that of the material of which the walls of the bodies are made and if Vi 'and Ve are respectively the internal and the external volume of the body,

said body has a positive floatability if:

7 Vi a 1 JD The iioatability is the greater as the first member of the above unequality exceeds the second member. Mechanical considerations supply the lower limits below which the thickness or the walls must not decrease. From this point of View itseems preferable, at the present time, to use a hollow sphere, which has a geometrical shape well adapted to resist compression. The risks of breaking of the body appear when the tension supported by the wall is equal to or higher than the elastic limit of the material. It is therefore necessary to use the material below this limit. The,

tension t on the inner wall of a sphere subjected to an external uniform pressure P is given, according to Lam, by the following formula:

BRS

i wherein Rand rare the external and internal radii of the sphere, respectively; In the case of asphere made of steel,

the physical characteristics of which are as follows: density 7.7, yield point 80 lig/mm?, it is possible to arrange so that the material'works under tensions lowerfthan orequal to 25 "kg/mm?, in ordertohave afsuliicient safety margin.- f

In theser conditions, with'an" external pressure'averaging 100 kg./ 6111.2, the Lam formula indicates that the ratio of the radiimust be equal 'to 1.021. Y'I he. resulting density is.O.,462,` The sustaining pow'erof such spheres is there# fore much higher than that of solids.

It is possible to Y reach higher sustaining powers' by making use of materials of lower densityv but having good mechanical characteristics.'V For instance, with glass, in the same conditions .of

utilization, the density will be only 0.138.

^- Of course,'the spherical shape is not theonly oneV that can be used according to our invention. Y n

According to the present invention itis possibleiurther FIG. r3V is an axial section of a hollow body used according to thepresent'invention. f" Y The machine according to FIG. 1 comprises a cabin 1, with thick Vwal-ls capable of resisting the external liquid pressure, supported by a oat 2 divided by walls 3 into compartments 4, 5, 6, 7,8, 9, 10, 1^1,12. The division of this oatinto compartments facilitates the balancing of the machine and improves safety` in case offshocks. The compartments in question each containa suitable amount ofsolid sustaining bodies 31. Each of the iioat compart. Y ments' 4, 5,16, y'7, 9, 1), 11 and 12 contain solid sustaining bodie'sr31f' However these bodies 31 do not iill up the above mentioned compartments bu'tzleave some free space therein, which can be occupied'either by water entering through ,holes 32 providediin'the lower walls thereof (the dimensions of said holes 32 being of course smaller than those-of bodies 31 sothatsaid bodies'cannot escape from to increase thefresistance to external pressure Vof the holv e low bodies that are used without considerably increasing their appar'ent'density by llin'g the recesses with'a fluid under pressure Aand in particular with a gas'under pressure.

For instance thel internal pressure in the hollowfbody will n be 'one'half of the hydrostatic pressure;

By proceeding in this manner, it is possible to reduce byY nearly onehalt the valueof'the apparent density of the hollow body. Of course the fluid that is used 'must have a density as low as possible. vBy way of non limitative ex-V ample we may operate as follows: A glass tube,.one of l the ends of which is initiallyV closed, is cooled in liquid nitrogen. YIt is subsequently partly filled with a certain y' and'13a connected through the ci'rcuitrshown by FIG. 2

= with the central chamber or compartment 8. This circuit comprises in particular aV compressor 14 adapted to work in bothdirections, that is to lsay capabler of transferring Y gas from containers 13 into Ycompartment 8 and inversely frorncompartment 8 into containers 13 and 13a. The gas y' circuit has been shown for compartment 8 buto course amount of a liquefied gas and the tube is finally sealed.

The gas thus imprisoned in the glass tube creates, at nor- The thickness mal temperature, the desired pressure. Y necessary for the walls of the tube can easily be calculated by means of the Lamformula. Concerning the sealing of the free end of the tube, it constitutes any operation without special diiiicultiesrfor someone skilled in the art.

It is interesting to note here the interest, from the point 1 1; .40

Y tion with cabin 1.

of view of safety, of using a highly divided-ballast such as obtainedib'y the use of hollow bodiesac'cording to the present invention. The risks of accident resultingl from shocks or mechanical accidents are greatly reduced.V

similar circuits may exist between containers 13 and 13 and compartments k4, 5, 6, 7, 9,111,11 and 12.

r For the sake of safety, the machine further `includes weights placed lin boxes 15 xed to cabin 1 and which can be dropped'separately.

r VHorizontal propulsion of the machine is obtained by means diagrarnmatically shown at 16.

I The central compartmentS, which is provided at the bottom thereof with communications with rcompartments Of course the presenty invention comprises the adapta-V'.Y

tion to existing machines of sustainingdevice vusing .as active elements solid bodies such as above specified, which may replace more or less the sustaining means used prior to this invention. To be more deiinite, the invention is concerned with 'a submarine machine wherein the iloat,V

v machine being possibly further characterizedby at least one of the following points: Y Y

(a) The machine comprises a compressor plant making it possible to force a gas under pressure into at least one f compartment so as to drive out watertherefrom and whichY may work in the reversemanner when it is desired to ex- 7'and 9 jin'addition to its use to control thel vert-ical displacement ofthe rmachine further serves as communica- For thispurpose it is tted :with closing means diagrammatically indicated at 17 and 18.

Finally cabin 1 is provided with windows 19 and l2i) for guiding the machine'and observing the surrounding medium.v We will now describe with Vreference to FIG. 2 the gaseous 'circuit`forcontrolling the vertical displacements of they rmachine by transfer of gasV between . containers 13 and 13 on the Yone hand and compartment 8 -on the Y Pressure gauges 22 land 23 measure the pressures exist-r ing respectively in containers 13 and'13a and in comparttract the gas from said compartment and` to lill said com-V v i.

partment with water;

l (b) The machine comprisesr a special compartment f giving it a complete automaticity for its vertical displacements;

(c) The machine is provided with weights which can be dropped either separately or at a single time;

(d) The machine is provided with a propelling device' for horizontal displacement; Y Y

(e) The machine is tted with auxiliary means forl per- Y forming various works during immersion. y

A preferred embodiment of our `invention'will be her yinafter described with reference to the appendedY drawings,v

given merely by way of example, and in which:

FIG. 1 diagrammatically shows, in verticalfsection, a"

machine of FIG. 1;

the

n ment 8. For instance, the'vertical displacement velocity may vary according to a given law, or the depth at which theimachine is under the surface of water may be kept gas containers 13 and13a with a distributing machine 30 for sending gas to the other compartments. v

I iIG. 3 is a sectionalview of a hollow bodyi made of cylindrical portions 33 and 34.shrunk on each other and semi-spherical end portions 35. f

In Va general mannerhwhile we have, in the above description, disclosed whatwe deem to be a practical and eficientembod-iment Vof theinvention, it should be well v understoodV that We donot Wish tofbe limited thereto as V there `might be changes made in-the arrangement, dispositionand Vform of the parts withoutdeparting from theiprinciple;- of the present invention as comprehended within the scope of the Vappended claims.

What we claim is:

1. A submarine machine comprising a frame and a Xed number of sustaining bodies at least the outer wall of which is solid and uninterruped, said bodies being operatively connected with said frame to transmit thereto an upward thrust, the specific gravity of said bodies being less than 1 and their compressibility being less than that of water, the number of said bodies being such that the total upward thrust they exert in water on said frame is equal to at least a substantial portion of the total apparent weight in water of the remainder `of said machine.

2. A machine according to cla-im 1 wherein said bodies are made of a non porous solid substance.

3. A machine according to claim 1 wherein said bodies are made of a solid substance having a multiplicity of non communicating cavities therein.

4. A machine according to claim 1 wherein said bodies consist of a solid substance and a watertight coating surrounding said substance.

5. A machine according to cla-im 1 wherein said bodies are hollow solid bodies.

6. A machine according to claim 1 wherein said bodies are hollow solid bodies filled with a gas under pressure.

7. A submarine machine which comprises, a frame, a float rigid with said frame comprising a plurality of compartments, at least some of said compartments being provided, at the bottom thereof, with openings placing the inside thereof in communication with the outside, a cabin, a xed number of sustaining bodies in said last mentioned float compartments, at least the outer walls of each of bodies being solid and uninterrupted, the specific gravity of said bodies being less than 1 and their compressibility being less than that of water, the number of said bodies being such that the total upward thrust they exert in water on said oat is equal t-o a substantial portion of the total apparent weight in water of the remainder of said machine, and means carried by said frame for driving a gas into at least some of said compartments to expel water therefrom.

References Cited by the Examiner UNITED STATES PATENTS 2,857,873 10/ 58 Norelli 114-50 3,104,641 9/63 Froehlich 114-16 FOREIGN PATENTS 622,900 5 49 Great Britain. 1,261,635 4/61 France.

PERGUS S. MIDDLETON, Primary Examiner.

MILTON BUCHLER, Examiner.

Claims (1)

1. A SUBMARINE MACHINE COMPRISING A FRAME AND A FIXED NUMBER OF SUSTAINING BODIES AT LEAST THE OUTER WALL OF WHICH IS SOLID AND UNINTERRUPED, SAID BODIES BEING OPERATIVELY CONNECTED WITH SAID FRAME TO TRANSMIT THERETO AN UPWARD THRUST, THE SPECIFIC GRAVITY OF SAID BODIES BEING LESS THAN 1 AND THEIR COMPRESSIBILITY BEING SUCH THAT THAT OF WATER, THE NUMBER OF SAID BODIES BEING SUCH THAT THE TOTAL UPWARD THRUST THEY EXERT IN WATER ON SAID FRAME IS EQUAL TO AT LEAST A SUBSTANTIAL PORTION OF THE TOTAL APPARENT WEIGHT IN WATER OF THE REMAINDER OF SAID MACHINE.

Images