US2400290A - Impulse pumping system - Google Patents

Description

May 14, -1946. cLANcY y IMPULSE PUMPINQ SYSTEM 2 sheets-sheet 1 Filed April 20, 1942 's l ilkrflmay .')fhrwt May 14, 1946. Aca. E. czLANczYl 2,400,290

'nunmsruurme sYsT'nu l lFiled Apm 2o. 1942 2 sheets-sheet 2 Prasad May I14, V194s UNITED STATES PATEN 'r oFFi-CE munss PUMPmG SYSTEM Application April 20, 1942, Serial No. 439,672

Claims.

This invention relates generally to systems for pumping liquids through evaporators, the general object of the invention being the provision of an improved liquid pumping system operable' by virtue of periodic pressure impulses generated by periodic vaporization of a relatively 4small quantity of the liquid of the system.

The pumping system of the invention has several illustrative practical applications, a somewhat detailed consideration of which will lead j to an understanding of the broad underlying principles of the invention itself. One of these is as a circulating pump for a waste-heat boiler system, such as may be used on aircraft for steam generation purposes. In such systems, some of the heat of the exhaust gases of the aircraft engine is reclaimed by means of a boiler or heat exchanger associated with the exhaust pipe. In accordance with the present invention, heat derived from the exhaust gases is utilized to periodically vaporize a. relatively small quantity of water which collects in a leg of the system, thereby generating steam impulses which act in a pumping chamber to drive a larger quantity of water contained therein to and through the boiler.

Another illustrative application of the invention is as a pumping system for the refrigerant medium in a refrigeration system. In this case, a small quantity of refrigerant is periodically Vaporized in a leg of the system, for instance, by subjection to surrounding atmosphere, or by heat transfer from the incoming refrigerant medium. 'I'his vaporized refrigerant acts in a pumping chamber to drive a larger quantity of liquid refrigerant contained therein to and through the cooling pipes. The advantages of this pumping system from a refrigeration standpoint will. be

. discussed at a later point herein.

With this brief preliminary discussion in mind, the invention will be best understood by now referring to thev following detailed description of certain typical illustrative embodiments thereof, as applied both to waste heat boiler systems and v to refrigeration systems. For this Purpose reference is directed to theaccompanying drawings, in whichf Fig. 1 is a diagrammatic perspective view show- (Cl. (i2-425) Fig. 5 shows a modification of the refrigeration system of Fig. 4.

With reference firsty to Figs. 1, 2 and 3, numer-v alv I0 designates generally a conduit for hot gases; for'instance, it may be the exhaust pipe of an aircraft engine. Arranged in heat absorbing relation toexhaust pipe I Il is a heating coil II; here diagrammatically indicated inthe elementary form of a coil of tubing I2 wrapped about the pipe I0 in contact therewith. The two elen ments III and I I together typlfy a heat exchanger element or fluid heater or boiler in which liquid may be heated or evaporated. The element is here shown only in diagrammatic form, since it, per se, does not necessarily form a part of the present invention; for a disclosure of an eilicient boiler or heater suitable for the purpose,

see my copending application, Ser. No. 432,959,

filed March 2, 1942, entitled Heat exchange apparatus.

The coil of tubing I2 receives liquid, typically n water, though not necessarily so, by way of a conduit I3 whose open end I4 (see Fig. 2) is 1o-v cated inside and near the lower end of a closed impulse pump chamber I5. The chamber I5 receives its water by gravity flow from a header or. tank I6 vla pipe Il, the lower end of which is coupled by means of fittings I8 and I9 to a niption 2I of fitting Il is screwthreaded into the box Y ple 20 on the top Vof chamber I5, an inverted normally open check valve V being placed above nipple 20. As here shown, the tubular lower end porzzrorming the upper part of the stung I9, and coniined between the lower end of tubular portion 2I and annular upwardly facing shoulder 23 formed inside box 22 is a check valve seat disk 24, furnished withperforations l5,- and from the center of which depends a headed valve stem 26, the latter carrying a light, vertically movable check valve disk 2l. This check valve disk 21 .is adapted, upon development of pressure below it, to rise on stem 26 into engagement with the underside of plate 24, thereby closing per-l forations 2,5. A vpipe leg or other conduit 30, opening at one end inside the upper portion of A. chamber. I5, is arranged in heat absorbing relation to the hot exhaust pipe I0, being here shown as given a partial turn about pipe III in contact therewith. The end 3l of this leg 30 is closed, as indicated in Fig. l. The leg may be of any suitable form; it is only'necessary that it com-:f

municate openly only with chamber I5.

In the illustrative circulation system here instanced, the outgoing end of the tubing I2 is connected by line 34 into a separator 35, of any conventional type, and indicated as equipped with a usual baiiie, 36, the water separated out draining via connection 31 and T-fitting 38 into header tank I6, and the steam being discharged from the separatorto line 39. This steam iiowrelation to the steam line 39, thus, line 4I is shown in Fig. 1 as placed in contact with the steam line 39,Y the two being preferably surrounded by a metal sleeve 42 of good heat conducting properties, as copper.

Water is conveniently introduced to the system by way of a removable plug 44 screwed into the top of header tank I6. The quantity of water utilized in the system is not critical, it being only required that suflicient water be utilized to assure circulation and the desired heat absorption from the exhaust pipe. Valve 21 being in its lower or open position, water contained in tank I6 drains through pipe I1 into chamber I5. This water rises in chamber I until it iiows into leg 30, and' thence into heat absorbing relation with exhaust pipe I0. The water within the chamber I5 may at this time rise to a level such as indicated at L in Fig. 2. The water containedin leg 30, or some of that water, is converted into steam, which then discharges into chamber I5, creating a steam pressure therein ycausing valve 21 to be elevated and closed, and forcibly expelling a charge of water from chamber I5 by way of pipe I3 into the tubing I2 of boiler I l. A substantial quantity of water, which may equal approximately to the volume of chamber I5, is thus pumped through the boiler II, wherein it is converted into steam, and from which the steam is discharged via line 34. This steam flows through separator 35, wherein any particles of water are separated out to be returned immediately to tank I6, and thence on via line 39, through any steam utilizing apparatus which may be connected in said line, finally to be condensed at 40, and the water delivered by the condenser is returned by line 4I to the tank I6. Immediately that the steam pressure so built up within the chamberI5 has been dissipated, valve plate 21 lowers and permits the vchamber I5 to reiill with water'from tank I5,

and the cycle is repeated. Thus, bya series of pressure impulses, generated through vaporization of the small quantity of watervcollecting intermittently in the leg 30 of the system, substantial charges of water are' forced' intermittently into the boiler, wherein they-are converted into steam, and from which the steam-is intermittently discharged via the line 34.4 'I'he im.

The system as described furnishes a positive, intermittent iiow through the boiler, and is capable of handling a relatively large quantity of ow per unit of time. y

I will now describe the application of my impulse pump to a refrigeration' system. By way of introduction to this aspect of the invention, it may be noted that the employment of a means for positively inducing flow of the refrigerant medium through the cooling coils or pipes has several most denite and important advantages. First, the substitution of positively induced flow for the conventional method of establishing circulation by balancing a column of liquid against the vaporizing liquid in the cooling pipes eliminates all necessity for the otherwise requisite delicately adjusted balance between the static liquid head and the friction losses in the cooling pipes, and makes unnecessary the otherwise essential precautions which must be taken to assure the constant rise of the vaporizing liquid in those pipes. And not only does positive pumping render the system comparatively independent of Afriction losses, but it makes the system substantially independent of the mechanical configuration or arrangement of the cooling pipes, eliminating the necessity of rise from intake end todischarge end, and permitting them, if desired, to be all in one horizontal plane. Moreover, and not least in importance, positive pumping permits establishment of a greater quantity of liquid iiow per unit time, with consequent increase'in rate of heat transmission.

Reference is now directed to Fig. 4, showing diagrammatically one typical application of my impulse pump to a refrigeration system. Numeral 50 designates generally a pumping chamber, corresponding to the chamber I5 of Fig. 1. and numeral 5I designates a discharge pipe whose open end 52 is located inside and near-the lower end of chamber 50. A heating leg 53 opens at one end inside the upper portion of chamber 50, and is closed at its other end 54. This leg 53 is to be understood as subjected externally to atmosphere, for instance to the atmosphere of the area which is to be refrigerated. As here shown, the pipe 53 is furnished with a series of heat absorbing fins 55.

A refrigerant supply line 55, understood to lead from a compressor or other source of refrigerant supply, discharges inside an accumulator 51 under control of ya suitable valve, which may typically be a float controlled valve, such as diagrammatically indicated at 58. This oat controlled valve may maintain thev liquid within the accumulator 51 at some such a level as indicated at L'. Refrigerant contained within accumulator 51 is fed by gravity t0 pumping chamber 50 via line 5S containing an inverted normally open check valve 50, which `may be of the same type as the valve V employed in the'system of Fig. 1.

Pipe 5I leads Vfrom chamber 50 to a trap 5I, which is connected by pipe 52 to one end of a set of refrigeration piping (heat absorbing coils) gencompressor, absorber, or absorption system, not

necessary to illustrate or describe.

Refrigerant in liquid form supplied via. pipe 55, is, as previouslydescribed, discharged under control of flow valve 58 into accumulator 51. the float maintaining the level therein at some predetermined height, such as indicated; A certain percentage of the liquid refrigerant so discharged within the accumulator 51, perhaps as much as 25%, immediately vaporizes, and the effect ofthe vaporization is to cool the remainder of the refrigerant within the accumulator, the temperature being lowered say to about F. This cooled refrigerant, in liquid form, flows via pipe 59 past'check valve 5.0 into chamber 50, wherein it rises until it flows into and fills the leg 53. As previously explained, the leg 53 is surroundedl by atmospheric air, or by the air within the region to be refrigerated. This air is at a temperature higher than that of the precooled refrigerant contained within the chamber 50 and therefore within the leg 53, and the effect of the heat transference from such air to the relatively small quantity of` refrigerant con-- tained within the leg 53 is to vaporize that z'efrigerant. 4The gas under pressure so developed discharges into chamber 50, closing check valve 50, and expelling the liquid refrigerant contained within chamber 50 by way of pipe 5|, trap 6i, and the cooling pipes 53. 'I'his refrigerant vaporizes and expands within the pipes 53, and the gas so produced is conveyed to accumulator 57 by way of pipe 64. The accumulator 51 may contain a separator baille 66, designed to remove liquid particles from the gas, and the gas remaining is recovered by way of line 55. Any-unvaporized liquid remaining in piping 63 after the movement of refrigerant through the pipes ceases will be caught in trap 6I if it tends to run back toward chamber 50. It is assumed that the proportions of the apparatus, and the volume of pressure gas, are 'such that all of lthe refrigerant liquid from 50 will have been pushed into the expansion piping 53 and that gas will .stand in the trap 6| as the movement ceases when the excess gas pressure has subsided. As soon as therexcess vapor pressure within chamber 50 has subsided, check valve 50 opens and permits the chamber to refill with pre-cooled refrigerantfrom accumulator 51. This completes the cyclejwhich then automatically repeats over and over, in a manner similar to that of the system of Fig. l.

Fig. 5 shows a modification of the refrigerator system of Fig. 4, in which the refrigerant in the leg connecting with the pumping chamber is. vaporized by heat transfer from the incoming refrigerant, rather than from atmosphere. For convenience, corresponding elements in the systems of Figs. 4 and 5 are designated by like ref. erence numerals, but with the sub-letter a an` nexed in Fig. 5. The incoming liquid refrigerant line 56a in Fig. 5 is connected to one end of a jacket 10 surrounding leg 53a, and leading from the other end of said jacket is a pipe 'il whichv discharges within the lower. portion of accumulator 51a, under control of float valve 58a, as will be apparent. tem maybe as in Fig. 4.

The incoming liquid refrigerant, at a tempera-i ture of, for instance, 90 F., flows through jacket 10 on its way to accumulator 51, its temperature being reduced perhaps 10 in passing through jacket 10 because of heat absorbed by leg 53a. As in the instance of Fig. 4, a certain percentage of the liquid refrigerant so .dischargedv within accumulator 51a is vaporized therein, substantially lowering the temperature of the remainder, 75 frigerant to said accumulator and establishing a 'I'he remainder of the syswhich drains via. line 55a and check valve 50a into chamber a. -Chamber 50a thus fills with liquid refrigerant, at a temperature of perhaps 10 F., which refrigerant finally. flows into and -illls legna. Heat absorbed from the refrigerant in jacket 10 vaporizes the quantity of refrigerant contained 'within leg 53a, and the gas pressure so developed closes check valve 50a and expels the charge of refrigerant contained within chamber 50a via line 5Ia and refrigeration piping 03a in the same manner as described in connection with Fig. 4.

It will be evident that there is no broad funda- Y may be atmospheric. though not necessarily so.,

It is contemplated, however,' that in addition to the inventive subject matter common to the boiler and refrigeration systems here instanced, each of said systems individually includesl sublject matter of invention peculiar to itself, which it is my purpose to cover within the scope of the appended claims. And it is to be further understood that the illustrative applications and forms of the invention here given are merely illustrative of and not limitative on the invention, and further, that various changes in design, structure and arrangement of the physical instrumentali ties here instanced may be made without departing from the spirit and scope of the invention or of the appended claims.

I claim:

1. Fluid pumping means adapted for use in a, refrigeration system that includes a source of refrigerant and refrigeration piping having inlet and outlet ends, said pumping means comprising: aV tank arranged to receiveliquid refrigerant from said source of refrigerant, valve means controlling iniiow of refrigerant to said tank and establishing a predetermined liquid level therein, a pump chamber having a liquid inlet connected to ,said tank, a check valve between said tank and chamber adapted to be closed upon development of fluid pressure within said chamber, a liquid outlet leading fromv said chamber from a point substantially below the upper end thereof and connecting with the inlet end of said refrigeration piping, and a heat absorbing liquid conduit communicating at'one end with said chamber at a pointr above the liquid outlet from said chamber and otherwise closed, said conduit being adapted to take refrigerant from said chamber when liquid rises to a predetermined level in the chamber, to

be vaporized in said conduit by heat absorption,

,and the vapor so produced discharging into said chamber to close said check valve and to pump the liquid contents of said chamber through said liquid outlet and to and through said refrigeration piping.

2. Fluid pumping means adapted for use in`a y refrigeration system that Aincludes a source of refrigerant and refrigeration piping having inlet and outlet ends, said pumping means comprising:

an accumulator connected to said source of refrigerant, valve means controlling inow of repredetermined liquid level therein, a pump cham` ber having a liquid inlet connected to saidl ac-4 cumulator at a point below said liquid level, a check valve between said accumulator and chamber adapted to be closed upon development of fluid pressure within said chamber, a liquid outlet leading from said chamber from a point substantially below the upper end thereof and connecting with the inlet end of said refrigeration piping, a fluid connection between the outlet end of said refrigeration piping and said accumulatorat a point above the liquid level therein, `a heat absorbing liquid conduit communicating 'at one end with said chamber at a point above the liquid outlet from said chamber and otherwise closed, said ,conduit being adapted to take refrigerant from said chamber when liquid rises -to a predetermined level in the chamber, to be vaporized in said conduit by heat absorption, and the vapor so produced discharging into said chamber to close said check valve and to pump the liquid contents of saidchamber through said liquid outlet and to and through said refrigeration piping, the liquid refrigerant vaporizing within said piping, and the vapor being delivered to th'e accumulator.

3. In combination with a fluid heater having a A heat source and an inlet and an outlet for a fluid medium, a. circulating pump comprising a pump chamber having a liquid inlet and a 'liquid outlet, said liquid outlet leading from the chamber at a point substantially below the upper end thereof and leading 'to said heater in'- let, th'e passage from the chamber outlet to and through the heater being freely open at al1 times, a source of liquid connected with said chamber inlet, a check valve between said source f liquid and said liquid inlet adapted to be closed upon development of fluid pressure within said chamber, the passage from the source to and through said liquid inlet being otherwise freely open, and a liquid conduit openly communicating at one end with said chamber at a point above said chamber outlet and otherwise closed, said conduit being adapted to take liquid from said chamber when liquid rises .to a. predetermined level in the chamber, and said conduit being arranged in heat absorbing association with said heat source, whereby liquid collected in said conduit will be vaporized by heat absorbed from said heat source and the vapor so produced discharged under pressure into said chamber to close said check valve and to pump the liquid contents of said chamber through said chamber outlet and -to and through said heater.

4. In combination with a fluid heater having a.v

heat source and an inlet and an outlet for a fluid medium, a circulating pump comprising a pump chamber having a liquid inlet and a' liquid outlet, said liquid outlet leading from the chamber at a point substantially below the upper end thereof and leading tosaid heater inlet, the passage from the chamber outlet to and through the heater being freely open at all times, a source of liquid connected with said chamber inlet, a check valve between said sourceof liquid and said liquid inlet adapted Ito be closed upon development of fluid pressure within said chamber, the passage from the source to and through said liquid inlet being otherwise freely open, a liquid conduit openly communicating at one end with said chamber at a point above said chamber outlet and otherwise closed, said conduit being adapted to take liquid from said chamber when liquid rises to a prede'- termined level in the chamber, and said conduit being arranged in heat absorbing association with' said heat source, whereby liquid collected in said conduit will be vaporized by heat absorbed from said source and the vapor so produced discharged under pressure into said -chamber to close said -check valve and to pump the liquid contents of said chamber through said chamber outlet and to and -through said heater, and a uid circulation line leading from said heater outlet and returning liquid finally to said source of liquid.

5. Fluid pumping means for use in a` refrigeration system that includes a source of refrigerant and refrigeration piping having inlet and outlet ends, said pumping means comprising: a tank connected to the source of refrigerant, valve means con-trolling the inflow of refrigerant to said tank and establishingfa predetermined liquid ,level therein, a pump chamber having a liquid upon development of uid pressure Within said inlet connected to said tank, a check valve between said tank and chamber adapted to be closed chamber, a liquid outlet leading from said chamber from a point substantially below the upper end thereof and connecting with the inlet end of said refrigeration piping, and a heat absorbing liquid conduit communicating at one end -with said chamber at a point above4 the liquid outlet from said chamber and otherwise closed, said conduit being arranged in heat absorbing relation to said refrigerant supply line, and said conduit being adapted to take refrigerant from said chamber when liquid rises t0 a predetermined level in the chamber, to be vaporized in said conduit by virtue of heat absorbed from the refrigerant flowing in said refrigerant supply line, the vapor s0 produced discharging into said chamber to close said chck valve and to pump the liquid contents of said chamber through said liquid outlet and to and through the said refrigeration piping.

, GILBERT E. CLANCY.

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