US2412740A - Rate of rise-dive indicator - Google Patents

Description

J. D. MORGAN ET AL 2,412,740

, RATE OF RISE-DIVE INDICATOR Filed April 14, 1945 2 Sheets-Sheet l OF' DIVE INDICATOR FEET PER sEcoND/ RAT RISE

- a INVENTOR. J74 B Yo/ 9 myz Patented Dec. 17,1946

UNITED STATES PATENT OFFICE RATE OF RISE-DIVE iNDIcA'ioR John D. Morgan, South orange, and Percy B, Levitt, Millburn, N. J assignors to Cities Service Oil Company, New York, N. Y., a corporation of Pennsylvania Application April 14, 1945, Serial No. 588,376

' 10 Claims. 1

This invention relates to navigational instruments for submarine vessels and the like, and is more particularly concerned with a device for indicating quickly and precisely the rate at which such a vessel is diving towards the bottom of the sea or is rising to its surface.

It is essential to the safe navigation of underseas craft that the extent of submergence shall be known at all times, and suitable instruments are provided for that purpose. These depth gages, which read in terms of feet of submergenoe, give no indication of an equally important navigational factor involving the element of time, that is to say, the rate at which the submarine is diving from the surface or is rising towards it. It is quite evident, for example, that the safety of a submarine which is cruising below the surface while observing a prospective target through its periscope will depend largely upon the ability of the crew to maintain the craft on an even keel at a depth of from say 30 to 40 feet. Under these circumstances the vessel still retains some degree of buoyancy so that it has a constant tendency to rise, which must be offset by the reaction of its control planes driving through the sea. Accordingly when it is noted that the vessel has started to rise prompt action must be taken to adjust the control planes, in order that the vessel may not break surface and become an easy victim for its intended prey, or, conversely, submerge to the point where it loses sight of its target.

Need for prompt action in offsetting a rise of the vessel is made particularly vital by reason of the slowness with which these heavy vessels respond to elevational control. More needhardly be said concerning the importance of this matter to the crew of a vessel which is cruising near the surface. It will be recognized, however, that prompt action may be equally vital in a vessel which is operating at fairly great depths, There have been cases, for example, in which the crew of a submarine cruising far below surface has failed to note the beginning of a rise at even a very slight rate, with the result that enough momentum was built up in the vessel to cause it to break surface against the application of the fullest degree of corrective action.

It will be evident from the foregoing that the problem is not only one of knowing that a change of elevation is occurring, and of knowing that promptly, but involves equally a determination of the rate at which the submarine is rising or diving as a basis for the applicatidnofjust that degree of plane deflection which is needed t6.

I oifset the change.

2 In this connection it will be appreciated that over-control of a submarine may be just as disastrous in its results as under-control; and that the middle course can be judged properly only upon the basis of accurate knowledge.

The principal object of the invention is to provid a navigational instrument for indicating the rate at which the submarine is rising to the surface or is diving toward the bottom in such precise terms as fractions of feet per second, and equally one which is adapted to give an indication or a change of elevation Within a fraction of a second after the inceptionof that change'and before the vessel has risen or dived more than a few inches from the level at which its commander has chosen to cruise.

ft is a further object of the invention to provide an instrumentof this kind which is not dependent for its proper functioning upon the total head of water acting upon its pressure-sensitive members, and which therefore responds just as rapidly and gives an equally accurate indicatio'ii of the rate of dive or rise near the surface of theses, as it does when the submarine is operatihg well below the surface. and at levels ap preaching maximum safe depths.

Another object of the invention is to provide a rate of dive-rise indicator having a safety valve which serves to shut off communication with the open sea when the pressure upon its sensitive, members approaches What may be considered a maximum safe value, and which accordingly serves to protect the instrument from damage when the vessel is forced to operate at extreme Theforegoing and other objects of the invention as well as its various features will be more fully developed in the following descriptionand one embodiment is illustrated in the accompanying drawings, in which Fig; 1 is a plan View of a rate of rise-dive instrument showing its indicating pointer and scale;

Fig. 215 asectional. view taken on the line 2-2 f Fig. r t

Ffig. 3 is a sectional view taken on the line 3-3 of F *ig. 2; and

Fig. 4 is a sectional view of a fragment of the instrument, the section being taken on the line 4 4 o Fig. 2. a

In the drawings, and referring to Figs. 1 and 2, numeral 9 indicates an instrument body having a dialfliii mounted in' its front end, which dial is marked 61f tenths of feet per second of rise 3 on one side of the zero point, and of dive on the other side; a pointer mounted to rotate on a centrally located shaft 2 so that its tip may sweep over the index marks on the dial to give a ready reading of the rate of change; and a protecting glass l3 lying between gaskets l4 and held in place by a bezel I5. The operating mechanism of the instrument, as may best be seen in Fig, 2, includes a metal bellows I6 which with a plate I! secured to its rear end forms a movable wall between chamber |8 that is normally open to the sea through conduit IS, on the one side, and a liquid filled system which is open to atmospheric pressure in sump 20, on the other side, to ether with a heavy spring 2|, which supports the bellows and is so calibrated as to permit limited movement thereof in direct proportion to the hy rostatic pressure acting upon plate H.

The sea water chamber referred to above is formed in the illustrated instrument by a housing 22, and a cover 23 to which the forward end of bellows I6 is secured, both of these parts being firmly fastened to a flange 24 formed on the rear end of body 9 by suitable stud bolts 25. The vent 23 allows for the escape of air during the filling of chamber I8 with sea water, and is normally closed by plug 21. Various other constructional details of the sea water chamber will be considered at a later point.

The liquid filled system referred to above includes a conduit 28 leading from the bellows and terminating in sump below the normal level of liquid 30 therein, and an orifice 3| for limiting the rate at which'liquid may be expelled from the bellows into the sump. In the illustrated device this orifice is formed by tube 28a, coupled at 33 to the lower end of conduit 28 proper, and having, a length such as to provide a desired fixed resistance The use of a tube for thispur pose means that the orifice may be large enough in cross sectional area to permit viscous flow so that the response of the instrument may be on a linear scale. It has the further advantage of making for manufacturing economy in that special parts do not have to be formed and assembled. and of making for ease of calibration of the finished device in that the total resistance of the orifice may be varied by adjustment of the length of the tube employed. It will be readily apparent, however. that where non-linear response in the completed instrument is desired with expanded sca e readings near the zero mark, a conventional orifice plate may be employed in place of tube 28a to restrict the flow of liquid between the bellows and sump.

Theliquid filled system also includes a pressure gage, generally identified by the numeral 34, which has a pressure sensitive member connected to conduit 23 at a point between bellows l6 and fixed orifice 3|, so as to respond to changes in pressure existing in the liquid filled system. In the preferred instrument a gage of the Bourdon type is .employed, having, its pressure sensitive tube 35 connected mechanically through shaft 36, a multiplyingsector 31 and pinion 38 to shaft l2 on which the indicating pointer is carried.

. It will. be assumed as a basis for a discussion of operating principles, that the instrument illustrated in the drawings is mounted in a submarine With its chamber |8 completely filled with sea water and open to the'sea through conduit l9. If the vessel is lying on the surface, the pressure acting upon the outside of bellows IE will be-substantially atmospheric pressure andwill be balanced by atmospheric pressure acting upon liquid flow or liquid through orifice 3|. The pressure in the liquid filled system accordingly rises to whatever valve is required to overcome the resistance of the orifice, and is of course reflected by an expansion of tube. 35, and a consequent movement of pointer across the face of dial l0. It will be evident to those familiar with the art that the pressure which is attained in the liquid'filled system bears a direct relationship to the force which is causing the liquid flow, and represents a measure of the rate at which the vessel is diving. If the dive is a rapid one, for example, pressure in chamber |B continues to build up and continues to displace the bellows to the left at a maximum rate, against the reaction of spring 2| and the resistance to fiowof liquid from the bellows through orifice 3|. The pres: sure needed to maintain flow through conduit 28 will be correspondingly high, and the indicating pointer of the instrument will therefore be swept across the face of the dial to indicate that the dive is approaching a maximum of two feet per second. In the course of a less rapid dive, however, and a consequent less rapid building up of pressure in chamber IS, a lesser pressure will be I required in the liquid filled system to maintain liquid flow through orifice 3|, and the deflection of the indicating pointer will be correspondingly smaller.

So much for the operation of the instrument to indicate the rate at which the submarine is diving. Assuming now that the vessel levels off at some chosen depth, it will be apparent that the pressure in chamber l8 quickly reaches a static value. Under these circumstances, flow of liquid from the bellows rapidly drops off until such time as the pressure in chamber l8 acting upon plate I1, is exactly balanced by the force of spring 2|. Concurrently, of course, the pressure in the liquid filled system falls off, allowing the pointer II to. swing back towards its zero point. At the point at whichequilibrium is reached there will, of course, be no flow in the liquid filled system, the pressure therein will be zero, and thetip of the pointer will stand opposite the zero'mark on the dial to indicate that there is no tendency on the part of the vessel either to rise or to dive.

Further consideration of the operating prin-. ciples of the instrument will, be based upon an assumption that the submarinestarts to rise from the level at which it has been cruising and which formed the basis of the foregoing discussion. Any movement of the vessel in an upward direction must necessarily be accompanied by a decrease in the hydrostatic head of sea water acting upon plate l! in chamber IS. The balanced condition which was discussed above will therefore immediately be disturbed, with spring 2| in this case displacing the bellows to the right as viewed in Fig. 2. In the course of this displacement liquid 33 will necessarily flow from sump 20 through conduit 28'into the bellows, and again that flow will be resisted by orifice 3|.- The. pressure in ccndu it -2 8 ;will- -accordingly drop'below' atmosresponse is attributable to several factors. it will be noted that we employ a liquid in the orifice 31 will also be constant. fore to employ a liquidwhich has a minimum "viscosity change over a wide range of temperature fluctuation. In this connection we have 'found 'that'a solution of about 47.75 per cent by weight of tricresyl phosphate, about 42.0 per cent ia iraero 'pheric pressure, resulting ina collapsing of Bourdon tube 35, and a swinging of pointer H in a counterclockwise direction. In this case, as

with the one previously discussed, the pressure which is built up across orifice 3| will be in direct spondingly small movement of pointer H. Conversely, a rapid rise of the vessel, and a rapid falling off of pressure in the chamber {8, will result in the creation of a relatively large difference between atmospheric pressure acting on liquid '30 and tending to force it from sump 20, and the pressureexisting in the fluid filled system at the Bourdon tube. In this latter case therefore, the pointer will showa high rate of rise,

approaching perhaps the maximum of two feet per second which the instrument is designed to indicate.

The utility of an instrument of the foregoing kind is largely dependent upon its sensitivity to small changes in pressure affecting its collapsible it responds to those changes.

high degree of satisfaction. Thus it is adapted to respond to a change in pressure in chamber 18 of from six to nine inches of water, which is to say that it responds to a similar change of position of a submarine, and of equal importance, it will reflect that change within about one-fifth of a second after its inception.

This remarkable sensitivity and quickness of First collapsible bellows system rather than a gaseous medium. Since the liquid'is itself substantially incompressible, any displacement of the bellows in either-direction is accompanied, to all intents @and purposes instantaneously, by aflow of liquid through orifice 3 l, and by an equally quick building up of a pressuredifference across the orifice to initiate a deflection of the Bourdon tube. Secondly, we find that best results are obtained by maintaining the liquid at a'substantially constant viscosity so that its resistance to flow through We prefer thereby weight of ethylene glycol monobenzyl ether, about 10.0 per cent by weight of triethylene glycol di-Z-ethylbutyrate, and about .25 per cent by weight of rust inhibitor, is particularly well suited for use in the foregoing device. .It will be appreciated, however, that other liquids may be found which will serve equally well, or that controlled heating may be employed as a means of maintaining the viscosity of whatever liquid is employed, at a substantially constant value.

The third factor which affects the sensitivity of the instrument, and a major one, has to do with the volumetric capacity of the pressure sensitive member 35. In this'connection we prefer to employ aBourdon type of gage because the tube of such-a devicerequires'ia minimum chang of volumeto" producewmaximum deflection of pointer 4 is at great depths.

lil Itis equally important, however, to maintain a proper ratio between the change in volume of element 35 required for maximum pointerdeflection, and the displacement of bellows [6 which is needed to produce that maximum pointer deflection. We have foundthat eminently satisfactory results :can be obtained by the use of a tube and. bellows system in which this volumetric .displacementratio is about 1:10. In the illustrated device, for example, tube 35 requires a change of volume of about .00045 cubic inch to produce a deflection of pointer ll from zero to the maxi- Min a greater ratio, means that only an insignificant part of the liquid in the system has to be .forcedfinto tube 35 tocause its distention, and

that ithe major partof the fluid is always available for flow through the orifice to buildup an indicating pressur in the liquid filled system. It accordingly means that there is substantially no lag between the time at which an unbalanced condition is created on opposite sides of the plate 1?, and the time at'whichthat unbalance is indicated by the movement of pointer H.

It will be apparent from the foregoing that the operation of the instrument is not dependent upon the actual pressure existing in the chamber it, but rather upon the rat at which that pressure changes. It accordingly i follows that the instrument responds equally as well to changes which occur when a submarine is operating near the surface of the sea as it does when operation This statement must be qualified, of course, to the extent that the pressure in chamber 58 must-not-be allowedto build up to a valve such as to burst the bellows IE, or to cause a permanent distortion of spring 2|. The illustrated instrument was designed, for example,ifor operation at all depths up to250 feet. In order to protect it against permanent damage in the event that itis carried to'greater-depths, we preferablyprovide a valve head 40, carried by bellows l 6, wh-ich is adapted to be forced against a seat ll when the pressure in chamber IBreaches a value correspondin to about 250 feet of water. The closing of that valve accordingly cuts off communication between pressure chamber l8 and th sea whenever the instrument is being sub- Jected to what might be termed the maximum safe value for its operation. Once the valve closes, of course, the instrument becomes inoperative, and stays so until the vessel rises above the 250 foot level. In thisconnection it shoul'd'be noted that valve head 40 is but very little larger than the valve opening in the rear wall of housing 22 which seat 4| surrounds, and accordingly that the vessel-need rise only a very little bit above the 250 foot level before that valve opens to reestablish communication with the sea, and to place the instrument again in operating condition.

toincreasirrgpressure' ln chamber "t8 forcesthe It may also be noted extension '42, and which, carries a threaded connection for communicating line H]. Any other suitable valve arrangement which serves a similar function may also be adopted in, building instru- Vments in accordance with our invention.

. In the foregoing discussion reference was made to the fact that the illustrated instrument has been designed for operation at a maximum depth of about 259 feet. .It will be appreciated, however, that the invention is not so limited in its utility and that instrument which are capable of withstanding much greater heads may readily be built in accordance with the principles hereinbefore outlined. In such cases, of course, the valve 4| maybe dispensed with if suitably strong springs and bellows are employed, or may be adjusted to shutoff communication of the sea at a pressure corresponding to the safe maximum pressures to which these instruments may be subjected.

diaphragm in direct proportion to the pressure applied thereto; a liquid filled system including the other side of said diaphragm as a wall there of and a sump which is open to atmospheric pressure; a flow restricting orifice in said system between said bellows and said sump; and a gauge for indicating pressure changes in said system resulting from displacement of said diaphragm, said gauge and said diaphragm having a displacement ratioof the order of 1:10;

- '2. A rate of dive-rise indicator for submarine vessels comprising a collapsible bellows; means for applying pressure to one side of said bellows which is directly proportional to the hydrostatic pressure of the sea at varying depths; a spring for supporting said bellows, said spring being so calibrated as to permit displacement of said bellows in proportion to the pressure applied'thereto; a liquid filled system including the other side of said bellows as a wall thereof, and a sump which is open to atmospheric pressure; a flow restricting orifice in said system between said bellowsand said sump; and a gauge for indicating pressure changes in said system, resulting fromcthe displacement of said bellows.

3. A rate of dive-rise indicator according to claim 9 characterized by a shut-01f valve for limiting the application of pressure to the firstmentioned side of said bellows, and means for actuating said shut-off valve responsive to the displacement of said'bellows.

, '4. A rate of dive-rise indicator for submarine vessels comprising a collapsible bellows; means for applying a pressure to one side of said bellows which isldirectly proportional to the hydrostatic pressure of the sea at'varying depths; a spring ,for supporting said bellows, said spring being so calibrated as to permit limited displacement of said bellows in-proportion to the pressure applied thereto; a liquidfilled system including the other side of said bellows as a wallthereof, and asump which is openlto atmosphericpressure; a flow restricting orifice in said system between said bellows and said sump; and a gauge for indicating pressure changes in said. system resulting from the displacement of said bellows, said gauge and bellows having a volumetric displacement ratio of the order of 1:10. 7

5. A rate of dive-rise indicator for submarine vessels comprising a pressure chamber; a collapsible bellows constituting one wall of said chamber; means for admitting sea water to said chamber to apply pressure to the outside of said bellows equal to hydrostatic sea pressure; a spring for supporting said bellows, said spring being calibrated to permit limited displacement of said bellows in proportion to the hydrostatic pressure applied thereto; a sump which is open to atmospheric pressure; a passageway connecting the inside'of said bellows with said sump at a point below the normal liquid level therein; said bellows, passageway, and a portion of said sump being filled With liquid; a tube of restricted cross section for resisting liquid fiow in said passageway between said bellows and said sump on a linear scale; and a pressure gauge connected to said passageway between said bellows and said orifice for indicating the rate of dive and rise of a submarine.

6. A rate of dive-rise indicator for submarine vessels comprising a pressure chamber; a collapsible bellows constituting one wall of said chamber; means for admitting sea water to said chamber to apply pressure to the outside of said lbellows equal to hydrostatic sea pressure; a spring for supporting said bellows, said spring being calibrated to permit displacement of said bellows proportional to the pressure applied thereto; a sump which is open to atmospheric pressure; a passageway connecting the inside of said bellows with said sump, said passage including a tube of restricted cross section which terminates in said sump at a point below the normal liquid level therein, and which serves as a viscous flow restricting orifice; and a Bourdon gage connected to said passageway between said bellows and said tube for indicating the'rate of dive and rise of a s-ulbmarine vessel, the Bourdon tube of such gageand said bellows having a volumetric displacement ratio of not substantially less than 1:10.

7. A rate of dive-rise indicator for submarine vessels according to claim-6 in which the liquid in said system has a substantially uniform viscosity over a wide range of temperature change.

8. A rate of dive-rise indicator for submarine vesselsaccording to claim 6 in which the liquid in said system comprises a solution of about 47.75% of tri cresyl phosphate, about 42% of ethylene glycol mono benzyl ether, about 10% of triethylene glycol di-Z-ethyl 'butyrate, and about 0.25% of a rust inhibitor, said percentages being by weight.

9. A rate of dive-rise indicator for submarine vessels according to claim 6 characterized by a shut off valve for said means for admitting sea water, and means operative responsive to the building up of pressure in said chamber for closing said ,valve.

10. A rate of dive-rise indicator for submarine vessels .accordingto claim 6 characterized by a shut-off valve for said means for admitting sea water, and means connecting said valve and said bellows whereby collapsing ofthe latter causes a closing of the valve. a l

. JOHN D. MORGAN. PERCY B.- LEVITT.

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