Патент USA US2406181код для вставки
2,406,181 ` F. J. WIEGAND.. ` ` FLQWMETER Filed Jan. 14, 1943 38 // INVENTOR FRA Nc/s d. W/:GA/vn. 4 « ` /a a’ if’ ATTORNEY ` Patented Àug. 20, 1946 y 2,406,181 ` UNITI-:D STATE s _PATENroF Fler. ` 2,406,181 FLOWMETER . Francis J. Wiegand. Ridgewood, N. J., assignor to' .Wright Aeronautical Corporation, a corporation of New York ' _ Í 1 Application January 14, 1943, seria1Nò.472,409 ",_ " l , ~ . , " 3 Claims.l (C1. 121-41) 1 This invention relates to measuring apparatus 36 in the wall of chamber 20 and this opening and is particularly concerned with apparatus for forms a seat for the valve 30. The valve 30 there transforming small pressure differentials into by controls the transmission of pressure from larger and more useful pressure differentials. l chamber 20 to chamber 32. Accordingly, the dia A typical'application of this invention is for measuring small low rates of fluid iiow by means of a venturi. Inaccordancewith this invention, the small dili'erential pressure produced by a low rate of iiuid flow through a venturi is transformed into 'a larger pressure differential. Thus, the apparatus could be used for measuring fuel flow phragm 26 is subjected to a force to ¿the right,í as .seen in the drawing, to balance the Vvforce ,act-¿ ing on diaphragm 274, the force acting on elia-` phragm 26 being equal to the pressure differentialv 10 ï between the pressure in chamber 32 and atmos; pheric A small pressure flow inortheother conduit balance I0 will pressure» subject the ' to an internal combustion engine. In the prior „ diaphragm 24 to a small force'to the left to open l art, in order to transform a small pressure dif 15 the valve 30. Pressure will then be transmitted from chamber 2!) to chamber 32 until the dia phragm 26 is subjected tov a suii‘lcient pressureY 20 acting on diaphragm 24.~ Upon an increase in iiow in conduit ‘,I0, the pressure differential on dia phragm 24 increases to further open the valve _30 until the pressure differential acting on the dia-` ferential into a larger pressure diiîerential, it is common practice to do so by using electric er pneumatic relays which control an external source of energy. It is an object ofthis invention to transform the small differential pressure to be measured into a larger pressure differential with out the use of any external Source of energy. ` differential to balance the'pressure differential Specifically, this invention comprises a dia phragm 26'has increased suiiiciently to again bal phragm system consisting of a relatively large ance the system»- Similarly, a decrease in flow» through the conduit I0 results in a decrease in diaphragm subjected to a pressure diiferential re sponsive to the condition to be measured and a , the pressure differential acting on the diaphragm second diaphragm mechanically connected to the 25 24v thereby moving the `valve 30 in a closing direc- » ñrst diaphragm for movement therewith. The tion. The bleed 34 inthe chamber 32 then per-. mechanical connection between the diaphragms mits a reduction in the pressure in this chamber> operates a valve for controlling the transmission until the pressure diiferential acting on `dia’- » of pressure from the high pressure side of the phragm ,26 has been reduced 'suiiiciently to again larger diaphragm to the high pressure side of the 30 balance the diaphragm system.` Thus, the valve> smaller diaphragm to balance- the diaphragm 3i|will assume a position to maintain the correct.v system. , . , . pressure in the chamber 32 to balance 4the d-ia- .' ,y Other objects of thisinvention‘will become ap parent in reading the annexed detailed descrip phragmsystem. . When the diaphragm system is balanced, the 35 pressure differential acting on the‘smaller dia- . tion in connection rwith the drawing, in which: Fig. 1 isa diagrammatic view of the invention; phragm 26 is necessarily largerthan the pressure -~ differential acting on the larger diaphragm »24 Fig. 2 is a diagrammatic view of a modification. in proportion to-the ratio of the areas -of these Referring to the drawing, a conduit I0 is pro diaphragms. Therefore,V since the pressure dif vided with a Venturi throat I2 for metering the 40 ferential acting on the diaphragm 24 is a measure flow of the fluid through the conduit. Conduits of the iiow through the conduit I 0,-the larger-y I4 and I6 connect the Venturi throat I2 and bar and more useful pressure differential acting on rel I3 with chambers I8 and 20, respectively. ' the diaphragm. 26 is also av measure of the` flow and ' ’ «l l These chambers are formed within a housing 22 by a flexible diaphragm 24. Thus, the diaphragm 24 is urged to the left, as seen on the drawing, by through4 conduit` I U. Accordingly, this larger pres. ' sure Vdifferential may be used to operate an indi cator calibrated so as to indicate the flowincon- v. a force proportional to the magnitude of. the flow duit I0. -Y through conduit I 0. A second diaphragm 26 'is mechanically connected to the diaphragm .24 by VVAt this_point 1tV shomd be noted that the reía tive sizeof the diaphragms must be correctly pro- Y portionedin View of thelmagnitude of the pres a stem 28provided with av poppet valvef30. This diaphragm 26 separates the chamber 32.from the sure diiîerential acting on the diaphragm 24 and , atmosphere or other balance pressure and a re strictive outlet 34 provides a drain bleed for the chambertothe atmosphere or-_other vent pres sure. The stem 28'pas`s'es througli'an'opening in View of lthe relative magnitude of these pres-j sures lasicompared 4to the atmospheric pressure .Y Aor other balance pressure to which the diaphragm 55 is subjected. Thus, if the diaphragm'ZE is too ' 2,406,181 3 . . v4 The apparatus has been illustrated and de scribed in connection with the pressure differen small or the pressure differential on the dia phragm 24 Vis too large, it will be impossible to develop sufficient pressure within the chamber 32 to balance the diaphragm system even though valve 30 is fully open. Also, with atmospheric tial created by a fluid iiowing through a venturi. However, the apparatus is of general application f and can be used wherever amplification of a small pressure differential is desired. pressure on one side of diaphragm 26 it i-s essen tial that the pressures on both sides of diaphragm While I have described my invention in detail in its present4 preferred embodiment, it will be obvious to'those'skilled in, theart,y after under 24 be greater than atmospheric pressure, other Wise it Will be impossible to balance the dia-‘5 phragm system. However, if the right side of the diaphragm 26 is subjected to other >than atmos-.l ,_ pheric pressure, it is only necessary that the pres-1l ' sures acting on diaphragm 24 be greater'tlfianA . ‘ standing my invention, that various changes and modifications may be made therein Without de parting from the spirit or scope thereof. I aim’ the appended claims to cover all rsuch modi this other pressure. As previously stated, Ythis in_ íications and changes. ' v vention may be used for measuring fuel flow toan internal combustion engine. In such case, a fuel pressure of 15 pounds per square inch is typical. ' `v I'cl'aimas my invention: , c ' l'. vInV apparatusk for transforming apsmall pres sure differential into a larger pressure differen ` k However, this pressure is only mentionedfby wayy ' ' of example. and is not to be construed as limiting tial, the individualpressures of. said small pres sure differential both being greater than atmos the use of the invention. pheric pressure, a housing, a ñrst movable mem-’ In Fig. l the amplified pressure differential acting on the diaphragm 26 is used for operating a remote Selsyn motor type indicator. The pres-v y sure from the chamber- 32 is transmitted vby a pipe 31 to a “Siylphon”>bellows38 so that this bellows Vis subjected to the same pressure diii’erential pei- wall ofthe high pressure chamber removedl fromV ber dividing said housing into a pair of opposedv chambers, means for subjecting said memberand», chambers to said small pressure differential, >theî said member having an opening therethrough> 25. into a third chamber, a second movable member ‘ unit-effective area as diaphragm 26. ‘The bellows 38 nis connected to thegvrotor of a Selsyn trans-_ mitter -40 bypa'rack 42 and a pinion 44. The _ ` in said third chamber connectedjto> said Víirst'> member for joint movement therewith by means; extending through said opening, said ._sectmdY ‘being ofgsmaller effective varea than 'said't Selsyn transmitter 40 is connected to a remote 30 ,member Selsyn receiver 46 >in ther conventional mannen '-'ñrst member, a Vvalve element Aformed on said~ connecting means for cooperation with saidopen Thus, the Selsyn receiver 45 ig responsive tothe pressure differential acting' on the diaphragm 26 so that the rotor of the Selsyn receiver may drive ing, 'the other side of said second member being an indicator 4_8> calibrated to read the _ñow in con-_ vent for said third chamber, and meansv respon sive to the pressurerdifferential across said sec-_; duit I0. ` Fig. 2 isa mcdincation of the system of Fig,y 1l illustrating al different type of ‘ indicating >means subjected to atmospheric pressure, a. restricted ond member. 2. Apparatus for transforming a small fluid. responsive to the differential- pressure acting on pressure dilferentialinto _a larger pressure diifer- , the diaphragm 2,6. That portion of Fig. 2 similarY 40 ential comprising a housing, a first movablemem ber dividing said housing into a pair of opposed chambers, means for subjecting said chambers tovFig'. 1 has been’designated by similar reference numerals and no further description of this por tion of the apparatus is deemed necessary. In ' this modification the chamber 32 is connected to a chamberjSU-by a conduit 5,2. lA flexible dia? phrag'my 54v separates this> chamber fromv the at-_ lmosphere sothat this diaphragm'is subjected to and consequently said movable member to said, small pressure differentiaLa `third chamberfsep-` arated from the high pressure chambenof, said ' pair of chambers by a fixed partition, a' second.r movableA member of smallereffectivev area _than said iirst member anddisposed across saidthird the same pressure differential per unit area as chamber, :means extending through, an yopening, that acting against diaphragm. 26. A link arm 56' connects the diaphragm 45'4 to a _liexibleV cantilever . 50 in vsaid partition and connecting said „members“V beam ‘58 lso that the deflection yof this beam’ isl i for 'joint movement;v avvalve element Ymoi'fabley byn said -connecting meansl and cooperating withklsa'id ’ proportional to the pressure differential acting against d_iaphragms'Zû and 54. Y v' ` opening for `controlling the transmission Vo_fj- pres A pair of conventional granular` carbon type sure from said hig'hpressure, chamber to sa_id„ ambientY temperature surrounding the apparatus'- ible diaphragm to. said= small pressure differential,> is eliminated. If'V the apparatus is being used to the individualY pressures ofcsaid small pressure ' differential both, being greater than- atmospjneri‘cs- v resistances 60 and` 62 are mounted on opposite 55 third', chamber and consequently‘to one side offY said second member,A the oppositepside .of _said sides of the beam 58 so that deflection of the`l` second >`'member being subjected toa pressure less y beam isA operative thru insulating arms 59 and' 6l than either of the> individual pressures .of said ' to increase one of these resistances and decrease small pressure differential, said third chamber the other resistance. _These resistances form a pair of' arms of a conventional Wheatstone bridge 60 having a restricted fluid pressure leakage path therefrom, and `means responsive to the pressure.vv circuit 64. A galvanometer 66 or other indicator diiîerential across said second member.` , Y is connected across this bridgeV and may be cali-` 3, Apparatus for transforming a_ small pressure brated to read the iiow invv conduit I0, since the diiîerential into ka larger pressure differential:` ' deflection ofY beam 58 is proportional tothe pres--Y comprising a housing, 'aofirst liexible diaphragm . sure differential acting against the diaphragm 2'6. vextending across said housing and Vdividing_said . By'providing a pair of resistances 60 and B2op-` housing into a pair of chambers, means for sub- i positely responsive to the deflection of the beam ' jecting said chambers ¿and consequently said?lex'..Y 58 insteadV of justr one resistance, the effect of measure fuel> flow to an internalcombustion en-` gine„ elimination of the effect of ambient tem-ì perature is q_uite important because 0f the varia-` ì Y tion in temperaturev _of the engine under differ- ‘ ent Y operatingy conditions, pressure, a third chamber in said'honsing and.v separated from the high pressure_,vchamb„er„of.; said pair of chambers by a ñxed partition,I z_tïsecç!l 76 - ond flexible diaphragm ofjY smaller'effective"area'4 2,406,181 5 than said first diaphragm and extending across said third chamber, means extending through an opening in said partition and connecting said ‘diaphragms for joint movement, a valve element movable by said connecting means and cooperat ing with said opening for controlling the trans mission of pressure from said high pressure chamber to said third chamber and consequently 6 ' ~ to one side of said second iiexibie diaphragm, the other side of said second -ñexible diaphragm being subjected to atmospheric pressure, said third chamber having a restricted atmospheric vent, and a movable member responsive to the pressure phragm. differential >across « said second dia ` ' ’ FRANCIS J. WI-EGAND.