USRE14728E - huffman - Google Patents

Description

E. E. HUFFMAN. DEPTH INICATING DEVICE. APPLICATION man MAR. 1. 19's.

l B l g l l funi/n il lssued Sept. 23, 1919.

' UNITED STATES PATENT, OFFICE.

nnwnr n. or sr. Louis, IIssoUnI.

narra-miennes nnvrcn.

Specication of Reissued Letters Patent. Reissued Sept. 23, 1919. Urilnal lo. 1,246,870, dated November 13, 1917, Serial No. 125,448, illed October 13, 1916. Application for reissue led latch 1, 1919. Serial No. 280,192.

To all 'whom it may concern:

Be it known that I, EDWIN E. HUrrMAN, a citizen of the United States 0f America, residing atthe city of St. Louis, vState of Missouri, UnitedStates of America, have invented a certain new and useful Depth-Indicating Device, of which the following is such a full, clear, and exact, descriptionv as will enable any one skilled .in the art to which itl appertains to make and use the same, reference'being had to the accompanying drawings, forming-part of this specification.

My invention relates to a device for indica-ting at a point either adjacent to or remote from a liquid container the depth or quantit of liquid conta-ined therein.

ne of the principal objects ofthe inven. tion is to provide a suitable gasolene gage to be placed upon the dash or instrument board of an automobile to indicate'the de th of gasolene in the gasolene tank, regard ess of t e position on the machine in which-the gasolene'- tank is located.V A further object is to provide a relatively simple and inexpensive device of the characterand for the purpose specified, whichwill respond satisfactorily :to very slight pressures and will be compensated for the effects of temperature.'

Generally speaking my device comprises an indicating instrument` or gage and a tube extending therefrom and having an open end located near or at the bottom of the gasolene tank or other liquid container. The

gage comprises a pressure receiving chamber,

which has a flexible portion with whichis associated a suitable motion multiplying and indicating mechanism. The pressure in the tube and inv the ressure chamber is produced by the weight of the liquid inthe i tank, tending to force liquid into the tube against the confined air therein. This pressure varies proportionately to the depth of the liquid. l

In the accompanying drawings, whichl illustrate one embodiment of my invention, Figure 1 is a view partly in elevation and artly in cross-section of the entire' device;

1 2 is a t0n plan view of the instrument wit the glass cover removed anda portion of the indicating dial broken away; Fig. 3 1s a cross-sectional view `taken along` the lines m :v of Fig. 1; Fig. 4 is an enlarged plan view of a portion of the instrument shown in Fig. 2. Figs. 5 and 6 illustrate a.

` modification in method of connecting the tube to the tank.

Since the gasolene tanks in use on automobiles rarely exceed twelve inches in depth and many have a depth of only eight or nine inches, and since gasolene is lighter than water, ,the pressure on the air in the tubey 1, due to the difference of level between the gasolene in the tank and that in the tube after the same has risen as hi h thereinas the compressibility of confine air permits, is comparatively slight even when the tank is full. It results, therefore, that the resilient element whichresponds to variations in this pressure must be very sensitive and its motions, which are necessarily slight, must correspond to pressure changes,.or in other words, some portion of the element mustoc'- cupy the same Aposition each time a given pressure recurs. In order to meet these re-4 quirements, I employ al pressure receiving chamber, which comprises a rigid member or plate 2 anda diaphragm Shaving its edgessoldered or otherwise attached to the plate 2 to form therewith .an air-tight chamber, and in order that this diaphragm, which is preferably of Gelman silver, may bend under the influence of the applied pressure,

and also in order that the greatest motion of the diaphragm may be caused to always take place at a given point and to a constant lextent for given pressures, the diay llever 5, which lever is pivoted on the shaft 6 carried by the supporting frame 7. At the end of the long a-rr'n of the lever 5 is rigidly attached a compensating element 8, which is composed of two strips of `metal i having dili'erent coeilicients ,of expansion and welded or'otherwise fastened together. One of these strips may, for example, be of brass (8*) and the other of steel (8b). This compensating element 8 forms an arm which connects the lever 5 with the indicating needle 9 through a link 10 and a lever 11, which ses i is connected to the shaft .12" supporting` the indicator needle 9 moves,

needle. A spring-13, secured at one end to the frame 7 and at the other-to shaft 12,

se'lvcs to take up any play in the various connections of the multiplying mechanism just described. The dial 14, over which the may be provided with suitable graduations, whereby the depth and therefore the quantity of liquid in the tank 19 is indicated. In the case of tanks of otherthanrectangular shape the graduations may beso located as to indicate either i depth or quantity as desired. 4

n account of 'the fact that the volume of a given quantity of air-under Iuniform pressure Vvaries' with its temperature, and on account of the fact that there is an y'inequality inthe total linear expansion ofthe pressure chamber wall 2 and the diaphragm 3, the instrument .described would not ve inv .correct indication of the `depth of liqui the tank under varying atmospheric temperatures, `were it'not foi-.the 'action ofthe compensating' element 8.

' Arise in the tube 1 will tend to increase the volume which must' result either v'in further sion of the diaphragm, or cause the evel in the tank'. will be very slightly raised by.

. 4the-expulsion of a portion of the" slight amount of liquid in -the tube, the dierence` Y yof level between the liquid in they tube andv ter must rise. slightly.

so, of the rliquid'in the tube, indicated at 16, to

descend. But since thelevelof the liquid that in the ltank is` increased only slightly. To the extent,'however,.that it is increased the definitely :'increased, and, therefore, its cen- The dierence in the total amount :ofllinear expansion betweenthe plate or chamber Wall 2 'and the. diaa rise -in temperature tend to cause the indicator'needle 9.to occupied, notwi ph 3-1also tends to .push the center of the iaphragm upslight y. The eifects of i just described, would cupy a higher 'tion than it previously oc'- and' the.

quality of liqtiiid contained in the tankhad notl changed, uta rise temperature simultaneously affects the .brass and steel strips in the compensating element 8, and, since the linear expansion of the brass'element will y sa greater than that of the steel element, element 8 as a whole curve sli htly in such direction as to tend 'to movet e indicator needle 9 5;backward.v The lengthv of the` eletherefore, the degree of motion, 'of itsffree end connected to the link 10,- is

ment 8, and,

so proportionedthat theeifect of tempera? ture upon the motions ofthe diaphragm of the instrument is' compensated for and the givenquantity of.- liquid in thetank, notwithstanding wide changes in temperature to the temperature of: the A'air in pressure on the diaphragm 3 will bev act that the indicator. needle" remains. stationary for a service.

A portion of the tube 'injthe tank is preferably enlarged in order that a decrease in temperature of the confined air will. result in less total decrease in the length of the hich vthe device may Vbe subjected in actual-v vet* -conned air column `under a given pressure than would be the case ify the tube were of uniform diameter throughout. To illustrate,

let it be supposed that the` volume of the entire'air-filled portion of 'the device, in.

cluding thepressurev chamber, the connecting portion-0f the tuba-and the enlarged i i .portionjn 'the tank, is five cubic inches, and

the volumeof the enlargement-alone is four cubic-inches. A decrease in` volume of'the container air to 'the extent of one-tenth will permit approximately onehalf-a cubic inch of liquid to enter the tube, but the level of liquid in the-tube will notbe thereby raised' to as great anl extent as wouldfbethe case' under like temperature drops if the tube were not enlarged at the end. Theeect of temperature upon the relative liquid levels in the tank and in the tube, and consequently ragm istherefore. n'nnimizedb -so en- I as t0.

its capacity a large per cent. of thel total capacity of the air confining elements of the device. Since in practice .the device `i'srlikely. to be subjected to an atmospheric u n the variations in position'l of -the dia-` lyaieng the 4lower end of 'the tu 11i temperature range of somewhat over Fahrenheit and since" the volume of` air under constant pressure varies' approximately one -fth for 100 changeV in temperaairconfining conduit 4above the liquid level in afa the highest temperature should be a least approximately one .fourth the com# binedcapacity of the'remainder'of the con-n` duit and the pressure receiving chamber of` the instrument.. temperature liquid would lill the enlarge- Vma and-entera@ Smau tube which ease.; there would be considerable change in -level for small variations in temperature. ,l

. The openings 17 and 18 entrthe-tube'atf .slightly diferent levels, and t .v

relatively small to cause theliquid to pass" lll' 5 minimize thevibration of the indicating into and outl of the tube slowly and thus needle resulting from momentary changes in 'level of the liquid inthe portion of the tank in whichthe tube is situated and which sult from the swayingmotonsof a motor vehiclejwhen runnin Otherwise. ,at the lowestv i. 1.104'

eyare madeV iso i In the modified form of connection of the' tube to the'tank fshownin: Fi L 5 andl .6 a three-'way valve 15 is provid liquid from the' tank can be shut olf` and the liquid `wherebythe in, the tube drainedo. In this .way-the canse of any'faultyoperation of a givende'vice mayfrequently quickly loi ture the capacity ofthe enlargement of the ics.

changes. v

and

cated without withdrawing the liquid from the tank or removing the tube therefrom.

I am aware that modifications in the form and location of the compensating element and in other features of the instrument herein described may be made without' departing from the essence of the invention, and its scope is intended to be limited only as required by the appended claims.

Hav' fully described my invention` what I c aim as new and desire to secure by Letters Patent of the United States is:

1. A device for indicating the depth of liquids in containers comprising a closed pressure receiving chamber, one wall onl of t-he chamber being provided with a flexlble ortion and the remainder of the chamber being rigid,l means for applying to the pressure receiving chamber a pressure varying with the depth of liquid, an indicator, and means whereby the Indicator is controlled 'by the flexible portion of the wall of the pressure receiving chamber and including means to compensate for movements of the flexible ortion of the pressure chamber resulting rom the effects of changes in temperature.

.2. A device for indicating the depth of liquids comprising a flexible member, means whereby said member is subjected to a pressure varying with the depth of the liquid, an indicator, means where y the indicator is governed by the movements of said member, and an element responding to changes in its temperatureto control the motion of the indieator to compensate for movements of the `flexible member resulting from tl'ieeiects of temperature changes. v

3. A device for indicating the depth of liquids comprising a flexible member, means;`

whereby said member is subjected. to a pres-v -sure varying with the de th of the liquid, an indicator, means where y the indicator is governed by the movements of said member,

and an element composed of materials having different coefliclents of expansion for controlling the movements of the indicator to compensate for movements of 4the flexible member resulting fromy temperature 4. In an apparatus of the class described, the combination of a liquid containing tank, a. gage having a pressure receiving chamber,

a conduit extending from said chamber to a point in the tank, said conduit being rovided. with an opening whereby li uid) from the tank may enter it at a point be ow the level of the liquid in said tank,

. said conduit being also enlarged at its liquid receiving end, the capacity of said enlargement being greater than the combined caeating means actuated indicating pensating for the effect of variations in level.

pacity of the remainder of the conduit and pressure receiving chamber.

5. A device for indicating the depth of llquids, comprising an air confining conduit provlded with a flexible portioi and having an opening to receive liquid, whereby the pressure exerted bythe liquid will be communicated by the confined air to the flexible portion of the conduit, an indicator,I and rlneans whereby the indicator is controlled Y and including means to compensate for .movements ofsaid flexible portion resultmg from` the effects of changes in tem-- perature to which the device is subjected.

6. In apparatus of the class described, the combination' of a liquid containing tank, means for indicating the depth of liquid in said tank, air confining meansA for transmitting -pressure from the tank to the indicating means,A said air confining means being provided with an enlarged portion 'situated below the level of liquid in the tank and communicating vwith the tank to receive liquid therefrom, the capacity ofsaid lenlargement above the liquid level therein under condition of highest liquid level in the tank and highest temperature to which the device is subjected being at least approximately one-fourth of' the 'capacity of the remainder of the air conining means.

7. In apparatus of the class described, the combination of a liquid container,v a pressure receiving chamber having a flexible portion, -a gas confining conduit for transmitting from the container to the pressure receiving chamber a pressure varying with the depth of liquidin the container, said conduit being provided-with an enlarged portion situated below the level 1n the container and communicating therelwith to receive liquid therefrom, Ithe capacity of said enlargement above the liquid level therein under condition of highest liquid. level in the container and highest temperature to which the' apparatus is subthe flexible portion of the conduit of liquid jected being at least approximately onefourth of the combined capacity of the remainder of the gas confining conduit and the pressure receiving chamber` and indiby the fiexible porpressure receiving chamber, said means including means -for corntion of the of liquid in the enlargement due to changes in temperature to whichv the apparatus is subjected. 7

In testimony whereof, I have hereunto set my hand and aiixed my seal.

EDWIN E. HUFFMAN. n. 8.]-

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