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lÀug.'13, 1946. v‘ - ,"M._`P. MATUsz'AK l ' ~ »405,704 FLOWMETER Filed oct. 21, 1945 ` 2 sheets-sheet 1 1NVEN TOR. Mary on FY. MafuszaK BY _» A1195 . Patented Aug. 13, 1946 2,495,79@ UNITED sTATss PATENT orgies 2,405,704 FLOWMETERv Maryan P. Matuszak, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware l Application October 21, 1943, Serial No. 507,1@ 7 Claims. (Cl. ’I3-205) 2 This invention relates to the measurement of the rate of now of ñuids; and, in its more specific aspects, is concerned with improved apparatus for readily determining the rate of flow of various fluids, particularly gaseous and/or vaporous fluids. Numerous devices for measuring the rate of flow of ñuids have been developed and employed with greater or less success, heretofore. Among such‘that the calibration curve, for moderate dif ferential pressures, is substantially a straight line. Although the combination of porous tube and dif ferential-pressure gauge may if desired be con structed of any materials that are functionally suitable, it is recommended that construction material consisting primarily of glass be employed in the interest of simplicity. . changes correspondingly. After the device has been suitably calibrated, the readings of the ma nometer provide measurements of the rate of fluid flow. Experience has shown that present dayflowmeters of the character above described With reference to the porous tube itself, the 10 same may be fabricated from glass, as, for exam ple, by employing oneor more of the known tech niques for making fritted or sintered glass discs. On the other hand, the porous tube may be made With equally satisfactory results for the purposes 15 Lof my invention from any suitable commercially available porous ceramic refractory tube of prop er configuration that is inert to the fluid to be measured and that preferably can be sealed di rectly to glass without the use of a cementing or other special uniting or assembling material. It is to be understood, however, that a suitable ce ment or similar material may be advantageously employed to effectively seal one or more of the porous tubes in th'e desired location within the 25 remainder of the device of this invention. Un glazed refractory tubes; such as those ordinarily used for the insulation of thermo'couple wires and readily obtainable in a variety of lengths, di 30 ameters and wall thickness from several sources, tion comprises a device having an inlet and an outlet and adapted to be disposed across a con of considerable wall thickness cannot as a rule be united to the glass tube in this manner since the generally known and commonly employed flowmeters for measuring ordinary ñuid flow rates are those which lcomprise a combined orifice and differential pressure gauge, such as the con ventional U-tube manometer. These flowmeters include. as essential elements, a conduit through which the iiuid is transmitted and having an ori ñce disposed across th'e interior thereof, and a U-tube manometer having one of its arms in com munication with the interior of the conduit at a point upstream of the oriñce and its other arm in communication with the interior of the conduit at a point downstream of the oriñce. With this type of arrangement, when the rate of fluid liow through the conduit changes, the difference in pressure between the two arms of the manometer are entirely satisfactory and accordingly recom possess a number of disadvantages. For one mended. The type having a single bore is pre thing th'e calibration of this class of flowmeters ferred because of its uniformity in Wall thickness. is as a rule laborious and time-consuming, since ' I have found that >such tubes may be joined di -necessary measurements and calculations must be made for a plurality of diiîerential pressures 35 ` rectly and with a minimum of diñ'iculty to’he'at resistant glass of the class commonly referred to and readings within the operating range of the as “Pyrex,” provided that care is taken to avoid instrument. Another disadvantage of this type appreciable overlapping with the glass in the use of iiowmeter resides in the fact that solid par of porous tubes having a diameterI greater than ticles, such as dust, that is entrained in the ñuid, oftentimes become lodged or deposited in the ori 40 1 mm. Porous tubes having a diameter of about l mm. are generally so thin-walled that they can , flee, thereby changing the effective size of the _ oriñce andI resulting in erroneous readings. be successfully joined to a glass tube of slightly The flowmeter of the present invention contem greater diameter by inserting one end thereof a plates and actually does completely obviate or distance of about'l or 2' mm. into the glass tube substantially reduce the disadvantages and ob 45 and then softening the glass tube in that region jections discussed above as will be readily com bythe application of heat so that it contracts prehended by one skilled in the art as the instant and unites with the porous tube, thereby obtain disclosure progresses. Briefly stated, my inven ing an overlapping seal or joint. Porous tubes duit through which the fluid to be measured flows; a porous tubular member through which the fluid is transmitted on passing from the inlet to the outlet; and a differential pressure gauge. 'the overlapping joints resulting therefrom are likely to crack and fail. Relatively thick walled porous tubes may, however, beV elîectively sealed or joined directly to glass tubes of substantially The characteristics of individual porous tubes are 55 the same diameter by making the joint end-to 2,405,704 4 3 gauge in the nature of a U-shaped manometer end and without overlapping, either within or without the porous tube. This invention has for its primary object the provision of an improved fluid ñowmeter. One important object of this invention is to provide a rate of fluid ñow measuring device that is adapted to be calibrated more readily and I3 that is provided with a calibrated scale I4 and that contains a quantity of suitable liquid I5 which is immiscible with the fluid to be meas ured. Mercury is a satisfactory manometer liq uid in most cases. An upwardly extending tubu lar member I6 communicates with one arm of manometer I3 and with an inlet Il. A second quickly than orifice, capillary or like conventional upwardly extending tubular member I8 commu types of fluid ñowmeters. Another important object of this invention is` -10 nicates with the other arm of manometer I3 and with an outlet I9. interposed across member I8 th'e provision of a ñowmeter of the class indi and integral therewith is a bulb or surge cham cated that is characterized by the fact that a substantially straightline relationship exists be ber 20. - - l Upper unit II includes an inverted U-shaped the differential pressure of the ñuid thereacross. 15 tube 2I having a branch comprising a pair of par allel conduits «29 and 30 terminating in a de A further important object of this invention is formable bulb 3I. A porous tube 34 of the char to provide a fluid flowmeter so constructed and acter referred to above is disposed within tube arranged as to minimize th‘e possibility iof _the ZI at the junction of conduits 29 and 30 and is same becoming clogged or otherwise fouled by solid particles entrained in the fluid being meas 20 spaced therefrom to form anannular passage 35 therewith. The end of the‘porous tube 34 that ured, to thereby obtain a device that is capable is nearer inlet Il' is sealed to the interior of tube of being employed for extended periods of time ZI and the other end of the porous tube is flanged without appreciable diminution in accuracy. and 'sealed tothe interior of conduit 39 in the A still further object of this invention is to pro manner earlier described. Conduit 29 is provided vide a flowmeter that is adapted to pass greater with a scale 33. Mercury reservoir 3l is deforma quantities of various gases, suchas isobutane and .ble and the internal Volume thereof may be al other gaseous hydrocarbons, than air at corre "tered by any convenient means, such as the clamp sponding differential pressures within the Oper tween the rate of flow of ¿duid therethrough `and ‘ ating range of the ilowmeter. _ v . 'so My present invention has for an additional ob ject the provisionof a device ofthe character in dicated that is relatively simple in design, durable in` construction and’ reasonable in initial and maintenance costs; andthjat is capable of per ing Ymechanism generally indicated by reference numeral 36> within which reservoir 3| is adapted `-’to be positioned. 'Clamping mechanism 36 com prises a frame including a base 3'I and sidewalls 38mand 39. A rod 40 is in threadedV engagement with side wall 39 and extends therethrough. A forming its intended functions_in an'effective and 35 plate III is preferably swivelly connected to one eiii cient manner. ' _ ' end of rod 40 while knurled hand wheel 42 is rig , idly connected to the opposite end. It will be evi dent that by virtue ofthe construction shown and by reason of the deformable character of .reser skilled in the art upon a perusal of the follow ing detailed description and annexed dwawings 40 voir 3i, the level of the mercury inconduit 29 and porous tube 34 may be adjustedat the will which respectively describe and illustrate pre of the Yoperator to thereby vary the effective ferred embodiments of my instant invention, and The foregoing aswell as other objects and ad vantages will he Vreadily apparent to persons wherein . - » - v »Figure 1 is an elevation view of a preferred- em bodiment of this invention; ‘ ` Figure >2 is an elevational View of a modified embodiment of this invention; ' Figure 3 is 'a graph showing severa] calibration curves obtained for two flowmeters of the type length or active area of theporous tube. The internal diameter of porous tube 34 is „preferably the same as the corresponding diameter of con duit 29 in order` to facilitate judging -thelevel of the mercury in the 'porous tube as indicated bythe scale 33. ' ' ' . In practice, the fluid being measured enters th 50 device of Figure 1 through inlet Il', flows into illustrated in Figure l; and ` ï conduits 29 and 3i) and passes through the wall ‘Figure 4 is a graph showing two calibration ofporous tube 34 into annular space 35, and is curves obtained for a ñowmeter of the type il then discharged by way of outlet I9.v The back lustrated in Figure 1 and corresponding curves pressure exerted by porous tube 34 is measured by obtainedfor a flowmeter employing the` usual 55 manometer I3 as indicated by calibrated scale M. constriction ororifice in place of a porous tube. As this pressure varies with the rate of ñow of Referring first to Figure 1 for full under the fluid through the device, the reading of the standing of the construction of the Vapparatus manometer providesl a measure of the rate of illustrated therein, it will be noted that the same iiuid iiow. Bulb 29 serves as a surge reservoir consists Vof a pair of separable and preferably transparent glass tubular units, namely, a lower 60 . whereby any possibility of any manometer liquid I5 being discharged from the device by way- of tubular unit generally indicated by reference nu outlet I9 and thus loss is successfully prevented. meral _I9 and an upper tubularunit generally Although the porosity of an individual porous indicated by reference numeral II, which are in tube is usually substantially uniform along its duid communication and which are joined by entire length, the porosity of one tube may ydiffer tubular flexible distortable couplings I 2. Rub considerablyfrom that of another tube. In the ber constitutes a suitable material for couplings event it is desired to make two or more flow l2 in many instances. However, should the fluid meters of the same range, the relative porosity to be measured tend to attack rubber upon con tact therewith and result in premature failure . ' of two (or more) individual tubes may be deter thereof, it is considered advisable to use an ap-> mined by the temporary incorporation of each propriate synthetic rubber composition. 'orV the like as the coupling material. This is advocated shown in Figure 1 >and by passing a gas at a when the fluid under consideration is. for exam ple, a hydrocarbon ora mixture of hydrocarbons. Lower unit l!! includes a differential pressure the data‘thus obtained, a simple calculation will enable a person skilled in the art to ascertain the tube separately in an arrangement similar to that known flowrate through each, individually. From 2,405,704 5 v6 length> of one porous tube that is the equivalent functionally of a known length of the other por ous tube. If desired, the porosity -of a-particular dicated by .the fact that flowmeters A, B, and .C covered a tenfold >range >of flow rates, as is clear from Figures 3 and 4. In fact, the range of' ap porous -tube may be decreased by sintering Aor sub jecting the same to incipient fus-ion at an ele vated- temperature, kas »byl applying direct heat thereto with a >gas-oxygen flame. If a porous tube of yhigh refractoriness to heat is desired, it may be Amade of integrated particles of beryllium oxide. 10 ' The modification vof the invention depicted in Figure 2 is basically similar to that shown in Fig ure 1 and possesses the >added advantages of be plicability of the straight-line calibration appears to hold for fiowrneters of this type having all pos sible 'fiow rates.` It is thus clear lthat the .flow meters of this invention possess an important ad vantage in the ease and simplicity with` which they are calibrated, whereby much time and labor can be saved. . Figures 3 and e illustrate another advantage of the ñowmeters of .this invention, namely that these fiowm‘eters pass relatively more of Va vapor, ing so-mewhat sturdier in construction and of such as isobutane, than >of a gas, such Yas air. presenting the outside of the porous tube up 15 This advantage is quite unexpected and unpre stream to the ñow of iiuid being measured. In dictable. ' According to Graham’s well-known law this modification of the invention a single con of diñusion, it would be expected that a rela duit 43 takes the place of bothv conduits 2=9 and tively heavy gas like isobutane would be passed 30 of Figure 1. A porous tube »44 is central-ly dis through the flowmeter more, slowly than would posed within conduit 43 and is spaced therefrom 20 air; such a relationship is in fact shown in Fig to form an annular passage 155 therewith. The ure 4 for the old type of flowmeter having a sin upper end of porous tube-4f! is sealed across con gle vconstriction serving as an oriñce. Although duit 2|, as illustrated, and the lower end «thereof the present invention should not be restricted by is provided with a closure 24 which consists of a any theory, it is possible that this unexpected ef lens shaped glass element. >It will be observed 25 feet may be caused by an adsorption of the va that the mercury or equivalent liquid 32 is ad por on the surfaces of the pores of the porous mitted into annular space 45 to thereby vary the tube, whereby perhaps a substantially two-dimen effective length of porous tube »44. Obviously the sional liquid layer is formed within the porous mercury or similar liquid employed in the appa- » tube. ratus of either Figure 1 or Figure 2 does not pass 30 Thus it will be seen that the construction here through the corresponding porous tube. in shown and described is well adapted to accom In Figure 3 are calibration curves for two flow plish the objects of the present invention. It meters, A and B, of the type shown in Figure 1, will »be understood, however, that the invention for air, isobutane, and hydrogen. The curves are may be embodied otherwise than here shown, and straight lines drawn through the experimentally 35 that in the form illustrated certain obvious determined values of the ñow rates at a differen changes in construction may be made.- There tial pressure or pressure drop of 100 mm. of mer fore, I do not wish to be limited precisely to the cury. The experimental values were obtained by construction herein shown except as may be re collecting and timing the »gas passing through quired by the appended claims considered with the flowmeter at baro-metric pressure and room 40 reference to the prior art. temperature, and calculating the volumes at What I claim is: standard conditions (N. T. P1). Experimental .1. In a fluid iiowmeter, in combination, a con values are given also at pressure drops of 50 and duit, an inlet for admitting fluid into the con 200 mm. of mercury. It will be observed that, duit, an outlet for discharging fluid from the although the experimental values for the flow 45 conduit, a porous tube disposed inl the conduit rates at the extraordinary high pressure drop of and spaced therefrom to form an annular pas 200 mm. of mercury do not fall quite on the cor responding straight line, the experimental values sage therewith, one end of the porous tube being closed, means forming a seal between the other end of the porous tube and the interior of the within the usual and most convenient pressure drop range of up to about 100 mm. of mercury 50 conduit, sealing means for varying the effective do fall on the straight line. Consequently, to length of the porous tube, and a pressure gauge obtain a calibration curve for a flow meter of the for indicating the drop in fluid pressure occa type herein disclosed, all that is necessary is to sioned by the passage of fluid through the wall determine the ñow rate at a pressure drop of 100 of the porous tube. « mm. of mercury (or a corresponding upper pres 55 2. A fluid flowmeter comprising a conduit, an sure drop for a manometer liquid other than inlet for admitting fluid into the conduit, an mercury) and draw a straight line through the - points representing this now rate and the origin. outlet for discharging fluid from the conduit, a porous tube disposed in the conduit and spaced In Figure ‘i are air and isobutane calibration therefrom to form an annular passage therewith, curves for a iicwmeter, C, of the type shown in 60 means forming a seal between each end of the Figure 1 and for a ñowmeter, D, of the same gen porous tube and the interior of the conduit, eral design but having an orifice made in the means including a liquid immiscible with the fluid usual manner by constricting a glass tube. At a for varying the eifective length of the porous tube, pressure drop of 100 mm. of mercury, these two and a pressure gauge for indicating the drop in fiowmeters passed the same amount of air, 6.05 65 fluid pressure occasioned by the passage of iiuid liters (N. T. P.) per hour. While for fiowmeter C this one point was suñicient to determine the calibration curve, more than one point had to be determined for flowmeter D. Similarly, the single experimental value found with isobutane P at a pressure drop of 100 mm. of mercury was sufficient for flowmeter C but was not sufficient through the wall of the porous tube. 3. A fluid flowmeter comprising a conduit, an inlet for admitting fluid into the conduit, an out let for discharging fluid from the conduit, a porous tube disposed in the conduit and spaced therefrom to form an annular passage therewith, means forming a seal between each end of the for ñowmeter D. porous tube and the interior of the conduit, The wide applicabiltiy of the straight-line cali means for varying the effective length of the bration for the flowmeters of this invention is in- 'lil porous tube, said last mentioned means including 2,405,704 7 a container of variable volumetric capacity com municating with the interior of the porous tube, and a liquid immiscible with the fluid in the con- ì tainer, and a pressure gauge for indicating the drop in íiuid pressure occasioned by the passage of fluid through the Wall of the porous tube. 4. The iiowmeter in accordance with lclaim 3 wherein the means for varying the effective length of the porous tube recited therein includes a liquid immiscible with the ñuid. ' 5. A ñuid ñowmeter comprising a conduit, an inlet for admitting fluid into the conduit, an out let for discharging fluid from the conduit, a porous tube disposed in the conduit and spaced therefrom to forman annular passage therewith, one end of the porous tube being closed, means forming a seal between the other end of the porous tube and the interior of the conduit, means for Varying the effective length of the porous tube, said means including a container of variable . volumetric capacity communicating with the an nular passage, and a liquid immiscilble with the fluid in the container, and a pressure gauge for indicating the drop in fluid pressure occasioned by the passage of the fluid through the Wall of the porous tube. 8 Y6. A fluid flowmeter comprising a conduit con ñning the ñow of fluid and including an inlet and an outlet, a porous member disposed across the interior of the conduit and resisting the flow of iiuid therethrough, a pressure gauge for indi cating the drop in ñuid pressure occasioned by the passage oi fluid through the porous member, a sealing liquid in said conduit in contact with said porous member, and means for displacing the sealing liquid with respect to said porous member to Vary the area thereof through which the fluid passes. . '7. In a ñuid fiowmeter the combination com prising a conduit coniining the flow of fluid and including an inlet and an outlet, a porous mem ber disposed across the interior of the conduit and resisting the ñoW of fluid therethrough, a pressure gauge for indicating the drop in ñuid pressure occasioned by the passage of fluid through the porous member, sealing means in said conduit and positioned adjacent said porous member, and means exterior of said conduit> for displacing said sealing means with respect to the porous member to Vary the active area thereof through which the ñuid passes. MARYAN P. MATUSZAK.