Патент USA US2410522код для вставки
Nov. 5, 1946. w. s. POWELL _ , . 2,410,522 _ ' INLET VALVE FOR lGAS COMPRESSORS Filed June 17, 1942 BY'Y @vanaf-M l w ` Patented Nov. 5, 1946 ZAlÜßZZ UNITED STATES plilxTtEN'l‘vv` OFFICE rNLE'r VALVE Foe Gas oor/.transenne ì _ ~ ` 9 I William" S. Powell, Indianapolis, Ind., assignor to Marmon-Herrington Company, inc.,A Indian-~ apolis, ind., a corporation of-Indiana. Application J une 17, 1942, Serial No. 447,47€! _' 3 Claims. (Cl. 230-2) I 2 `In the operation of modern airplanes,r main of av barome'trically‘ sensitive cell l ‘lí in" such man-` tenance of a supply of compressed air is an essen , ner thatth'epas'sage between seatl lë‘and" valve- tial, While, at the same time, conservation oi it“ will varyf'inversely' with variations of baroìpower requisite for such maintenance is desirable. metric" pressure so that the successive masses“ of Heretofore, it has been customary t'o` provide 6 air which may enter the compressor during suc~v a compressor and a motor, generally electric, so cessíve-s‘uction strokes, atrnormalspe'ed-o‘f opera proportioned that the motor is capable of aotuat~ tioifiîo'f'th'eicompressor, willi be uniform,.i. e., lessi ing the compressor at full capacity at ground level « volume-‘of admitted air’> at atmospheric pressure~> to deliver compressed air to the desired maximum at 16W altitudes thanv at high( altitudes. pressure and in such an arrangement, at higher 10 As the mass of air in a" given >volume varies in“--> levels due to the lower pressureoic air supply, the maximum power of the motor is much greater versely with‘it‘s temperature, it may also be de than is required. ì cordan'ceï with variations init'einper'aturë of theV sirable' to control the- position of- valve Iliin ac~ rEhe object ofVY my invention is to provide an` improved method and means by'whiohthe quan 15 tity of air which may be-supplied-toa compressor on its suction stroke, at its normal rate of speed, will be varied in- accordance with the barometric pressure of the air supply and, as av supplement, inaccordance with the temperature of the air 20 supply, so that the massgof compressed air dis charged at each stroke (unit operation) of the compressor will be- substantially uniform irrespec» tive of the altitude of the apparatus and tern perature of the air supply. air supply', valve’ i6 being' near'erto` its seat,` at'. a given barometri‘cl prëssur'e’,.when the air supply isV cold' than when" the" airis at a higher’te'mpera ture. ‘ For that purpose, cell if'l’may be supported upon a thermally responsive support’ so that it’sîeiîectv on valve' I‘B will- vary with the' temperature on the surrounding air supply, or a thermally-re sponsive'element’ may be installed as _a part of the connection between cell Il andvalve I5 to attain the desired end. It seems probable that a ' 25 valve of the needle type, as shown in Fig. 5, wiltl The accompanying drawing illustrates my in vention. be' most convenient, though I wishY itrunderstood thatjmy invention is not limited’to suchY form.> The proper' contour of valve I'ôvmay be readily» Fig. v1 is a> diagrammatic illustration of` an em bodiment ofV my invention; determined mathematically' so that for all posi'- ' Fig. 2' an axial section of an appropriate coin- v 30 tions-of the valve relative to` its seat under cur“ presser inlet valve and- associate barometrically sensitive controller; " ‘ I Fig. 3Y an axial section of another trolled inlet valve; , v ~ formof con# y . . - Figwi a fragmentary section showing a- ther mally-responsive "addition to> the structure' of Fig. 2; Fig. 5a secti‘onronv an enlarged scale, of an. appropriate needle -valve and associate seat; and rent conditionsof supplyV pressure- (and tempera'f ture if_ desired) itr will permit only a flow of‘a` predetermined, _mass of air' per unit of time into;A the compressor. Uniform.massesof` airmaybe compressed to a. predetermined pressure- by the> expenditure...ci` uniformv quantities. of power. Consequently, the. motor.H il at low altitudes'will be’called uponfor ' the same amount of work as at higher altitudes' Fig. 6 a section, on a smaller scale, of a niotiii 40 and thereby maximum eñiciency 0i» the apparatus _F1-ed form. ' y v ln the drawing, laindicates'an air-compressor or any desired form' driven by a motor I`I and provided with a discharge duct I2 leading to ay storage chamber I3; and an ’inlet duct I4 openA to atmosphere. 1 ' - rllhe motor i I need only'be- powerful enough to obtained because va small motor capable at its maximum >capacity of. producing desiredl com pression of air obtained at ahigh altitude will still’be capable of effectively operating, thecorn pressor‘a't low altitudes. , p Referring» to Figs, 2 and 5; the valve It 'com prises a circumferential flange 2li which may'seatv eiîectively -drive vthe compressor at thev highest f on the annular seat I5, and a tapered plug'po'r-- contemplated altitude and, therefore, much too tion 2| the various diameters ; of which are so small to effectively drive‘the compressor at- full 50 proportioned as tofvariably block theeye of seat capacity when at- ground‘ 1evel.,- Therefore, in I5 as the valve is axially shi-ftedinaccordance order to render such a- motor effective at ground with altitude variations. level,I part of the inlet'du'ct lffl'comprisesa-valve seat I5 and cooperating valve-> It;- thef‘positionfci which relative to seat- I5~is subiectfto’ther-control Valve seat I5 is anchored in bore 22 of nipple 23 and valve I6 is biased toward seat I5 by a spring 24. - . 2,410,522 4 3 Note: Comparative areas: A 1/8 in. dia. hole has an area .0122 in.2 Attached to the inlet end oi nipple 23 is a cup 25 within which is the barometrically-sensitive cell I1. . In order that cell Il may respond in suñîcient amplitude to variations of pressure of the sur 5 rounding atmosphere, it is composed of two cups _21, 21, sealed together, mouth to mouth, at their perimeters and axially slidable' in a foraminous .000576: .00057 6X 19.5: .01122: .00756 sq. .53x28 1.485 1.485 in. Tes-o _ A §35" dia. hole has an area .0069 in.2 . .00756 sq. in.=area of the orifice to pass .000576 shell 28 which, at its perimeter,- is formed to fit» lb. of air/sec. ’ cup 25 and, at the same time, aiîord air passages 10 Y» Check: to valve seat l5, as indicated by arrows. Shell It” the pressure is 14.7 lb. 1 in.2 and the tempera 28 is held in place by a retainer ring 28'. ture is 0, one ft.3 of air will weigh .08635 lb. One cup 21 of the barometric cell, at its center, `An opening .00756 in.2 will pass n is anchored to shell 28 while the other cup „21, at its center, is provided with a pocket 29 into 15 which the adjacent end of valve i6 seats» As the pressure of the air surrounding cell Il decreases, the cell bulges at its center and this so positions valve I6 relative to its seat I5 in accordance withY .00402 X .685 the altitude of the device that uniform masses 20 of air Vare admitted vto the` compressor at what-v .003742 lb. of air per sec. (6l/2 times too much). ever maybe the altitude of the apparatus. , Therefore the opening will have to close to The proper contour of valve IB, taking account .00402Xä5 only of barometric pressures, may be determined t as follows: . - 1 If the total amount of movement of valve IE is designated by the letter M thenthe requisite movement of the valve for proper altitude posi tion will be proportionate parts of M as shown in Fig. 5 and outlined below. , late the air inthe proper amount. _ Actual values of D and M vary with the capacity of any device upon which the valve is used. The properrelationship, when the compressor oper ates to attain a maximum pressure of 1000 pounds, may be determined in the following manner: . t ' Valve Diameter of motion valve at M (M) (alt.) 0 0. 966D . m><~00756=1538=~00116 111.2 at 125° F. An opening .00116 in.2 willpass _.000615àî-'ÃX1507 :.000374 lb. ofl air/sec. at 125° F. 30'." t If the diameter of the total opening is desig nated by the letter D then the diameter of the valve at various altitudes must be made to match the amount of motion of the plunger and regu Altitude (feet) .000575 25E . In order to compensate for temperature varia tions, a 'ni-metallic temperature responsive cush , ion 30 (Fig. 4) may be interposed between valve l0 and pocket 29, expansion or contraction of this _ _cushion by reason of temperature of the sur 3": -` rounding air serving to lengthen or shorten the connection between cell I1 and valve i6. Cup 25 may be provided at its mouth with screens 3l and filter 32 held in place by ring 33. Referring to Fig. 3, 40 indicates the main body >of an inlet valve structure having an entry pas sage 4| provided with a valve seat 42. Cooperat ing with seat 42 is a. valve 43 anchored on one wall 44 of a barometrically sensitive cell I1', the opposite wall of which is provided with ears 45 45 pivoted at 46 to one end of a stem 41 projected through an arch 48'of body 4l] between nuts 49 and 50. Leading into passage 4l, on the discharge side . 044 . 084 . 965D . 963D . 128 . 961D . 168 . 208 . 384 . 960D . 959D . 951D . 532 . 659 . 940D . 926D . 771 '. 908D In use, stem 4l' may be so adjusted that, at . 860 '.891D . 930V . 854D ground level, valve 43 is spaced «from seat 42 to l. 000 Y, of Valve 43, is an inlet passage 52 controlled by a , 50 needle-valve 53. aiîord entry of the'proper mass of air to permit 809D motor H to function. The variables involved in the calculations can 551: all be simpliñed by utilizing the weight of the air to be‘handled rather than theïvolume, because themass varies continually with the altitude and the temperature. - ‘ . 1 cubic foot of air at 40,000 ft. weighs ‘ - ' As the altitude of the structure rises, cell l'l will bulge so as to move valve 43 away from seat 42 to admit additional volumes of air, at lower pressure due to altitude, so that the air flow through the structure in a unit of time, will be a 60 predetermined mass within the capacity of the compressor motor. ' It will be noted that with the described arrange ment, the masses of air which may enter the Assuming the compressor speed to be 4000 R. P. M. andthe displacement to be 3000 in.3 or 1.736 cu. ft./min., the inlet oriñce >must admit at allv times l.736><.0199=.0346 lb; per min., .000576 lb./sec'.V ` i ` Fliegner’s equation‘for oriñces (Trans. A. S. Mnxxvneiee) i’sÍ'W=f.53AçP/\/T>,. Weight: .000576 as above, ysolving forï ` ' A nl _.5313 ' ' N compressor for -successive charges will be uniform >’irrespective of variations of atmospheric pres ' sure. Therefore, this desired mass having been determined, an energizing motor for the compres sor'may' be’selected which, at its delivery speed; will operate at its highest efñciency at all times. 70 Such an arrangement therefore reduces to a min imum, weight and size of the unit. ' In order to minimize temperature effects, a construction'like that shown in Fig. 6 may be used. In this form an evacuated “sylfon” cell 21' has suñicient expansive axial resilience, when 5 2,410,522 external pressure is reduced, to move valve 2| from its seat. This cell is sup-ported in the main body 25 by the foraminous shell 282, as in the construction shown in Fig. 2. Because of the re duced air content of cell 21’ variations of tem perature of the surroundings of the cell have little 6 barometrically-sensitive, evacuated, inherently expansive cell associated with said elements so as to control their relative position in accordance with the pressure of air admissible between said two elements, and including a thermally-respon sive element interposed between said cell and one of said pair of elements. 3. The combination with an air 4compressor and 1. An inlet valve structure for air compressors, an actuator of insuflicient power to drive the same comprising a pair of elements relatively shiftable 10 at full capacity at ground level, of a valve con to control passage of air therebetween and a trolling the inlet of said compressor, and a bar barometrically-sensitive unit associated with said eiîect on the pressure Within the cell. I claim as my invention: ometrically-sensitive, evacuated, and inherently elements so as to control their relative position expansive cell within the influence of the air in accordance with the pressure of air admissible supply for said compressor and connected to said between said two elements, and including a ther 15 inlet valve to control its effective position relative many-responsive element interposed between the to the compressor inlet, whereby substantially barometrically-sensitive unit and one of said uniform masses of air will be drawn into the com pairs of elements. ~ pressor upon unit operation of said compressor 2. An inlet valve structure for air compressors, irrespective of the pressure of air supply due to comprising a pair of elements relatively shiftable 20 altitude of the compressor. to control passage of air therebetween and a . WILLIAM S. POWELL.