US1537264A - Method of and apparatus for elevating liquids by a multilift uniflow airlift system - Google Patents

Description

May 12, 1925. 1,537,264

E. M. ROGERS METHOD OF AND APPARATUS FOR ELEVATING LIQUIDS BY A MULTILIFT UNIFLOW AIRLIFT SYSTEM Filed March 24, 1923 4 Sheets-Sheet l i l M v L [nae/afar: Zola/WW5,

May 12, 1925.

M. ROGERS METHOD OF AND APPARATUS FOR ELEVATING LIQUIDS BY A MULTILIFT UNIFLOW AIRLIFT SYSTEM 4 Sheets-Sheet 2 fi zverlior:

Edwin MR gens,

Filed March 24, 1923 By his day,

May 12, 1925. 1,537,264

METHOD OF AND APPARATUS FOR ELEVATING LIQUIDS BY A MULTILIFT E. M. ROGERS UNIFLOW AIRLIFT SYSTEM Filed March 24, 1923 4 Sheets-Sheet 5 Jo 3 ol T 3 a a F 5 I 7a 3 3 Z 6 Z r 5 r rFWF ens;

4 6 7T 3m 5m m u M A Y B S D I U Q m S m H A w RL E m E Q. U T A R A P P A D N A 5 F 20 D 10 .H Um V- M UNIFLOW AIRLIFT SYSTEM Filed March 24, 1923 4 Sheets-Sheet 4 In lrenior: Edwin I! I? gens;

Dy in)! fli'ay,

Patented May 12, 1925.

UNITED STATES PATENT OFFICE.

EDWIN M. ROGERS, OF NEW YORK, N. Y.

METHOD 01* AND APPARATUS FOR ELEVATING LIQUIDS BY A MULTILIFT UNIFLOW AIRLIFT SYSTEM.

Application filed karch'24, 1923. Serial No. 627,405.

T 0 all whom it may cmwern:

Be it known that I, EDWIN M. Roonns, a citizen of the United States, residing in New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Methods of and Apparatus for Elevating Liquids by a Multilift Unifiow Airlift System, of which the following is a specification.

The resent improvements relate to the art of e evating liquids by means of the airlift, and to improved methods and apparatus whereby to effect the air-lifting operation in a continuous and economical manner, and especially by an improved multi-stage operation under the control of an interactive regulation and thereby secure a highly effective mode of "action, and an adaptability for successful use under a wide range of conditions, and for practically and rapidly elevating liquids to unusual heights in proportion to the initial submergence and while greatly reducing the losses,especially the waste of power, normally and hitherto resulting from the use of the air under a high degree of compression.

A leading object of the present invention is to furnish a method of air-lifting liquids whereby the liquid to be elevated may be initially received in a stream at the lower end of a primary uptake pipe, and then be conducted through any required number of successive elevation-stages to an outlet for final discharge, and be so conducted while maintained (throughout its path or course) in the form of a continuous stream not subjected, first, to dispersion. and then to reformation while the stream, in passing through successive uptake stages, is subjccted to successive aerations and de'aerations. Since, by means of this method, the flow of liquid continues in a highly constant and uniform manner hitherto not practically attainable, I have herein designated this peculiar and continuous flowage of the liquid as a uni-flow stream.

A further object is to provide a liquidelevating appartus in which the described uni-flow stream may be conducted in a continuous stream-form throughout its entire path or route from inlet to outlet, and be therein forwardly impelled by successive submergence-effects combined and coactive. with corresponding aerations and de-aeration stages; and which, for realizing this method and result, shall subject the uni-flow stream (continuously while in operation) to the controlling effect of a plus-atmospheric pressure at all points in the said path thereof, and, also, to an interactive re ulation of flowage and of submergence-eects in all (or in any desired plurality) of said successive stages.

A still further object is to furnish such an apparatus provided with means for obtaining said plus-atmospheric pressure, and an effective interactive regulation by the aid of a method of energy-conversion, whereby the kinetic-energ of a spouting column may be utilized at eacfi (or at one or more) of the de-aeration stages, for thereby producing a super-head pressure in an outlet channel of, and at the junction of, an uptake column with a next following and down-flowing submergence column, and for thereby also forming a liquid-column super-head supplemental to an otherwise normal submergence-head, so that at each down-turn por tion of the uni-flow stream the movement thereof will take place by a continued stream-form flowage and while maintained under the super-head pressure.

A further object is to provide an airlift system comprising successive single airlifts (whether these are two or more in number) which shall be arranged in the system, and shall coactively operate as airlift pairs having the airlifts thereof connected for interactive regulation; and, for thus purpose, also to combine and connect the uptake column of one said airlift (this column being longitudinally elastic by reason of its aeration) with the submergence column of a next following airlift, (this submergence column being, normally, longitudinally non-elastic owing to its relatively non-aerated condi- I tion), and so provide, (as hereinafter explained), for a time-interval to occur between certain of the inter-regulative functions, whereby to obtain a highly effective conjoint regulation as between a super-head portion of the submergence column of one airlift and a super-head ressure in a combined de-aerater and kinetic-energy converter of a preceding single airlift of the system.

It is also a further aim and purpose of the present invention so to employ the numerous advantages peculiar to said method, and so to organize and operate the apparatus as a whole and in detail, as to minimize the losses hitherto normally incident to the airliftin method and to improve the character the cooperation and functioning of the method and apparatus, for thereby securing an aggregate efliciency, and dependability of action, whereb this method may be substituted,practically and with commercial advantage as to operating cost and maintenance,-for the ordinary and much more expensive pumps or like machines for either temporary or permanent use in rais- I by itself, but will operate together conjointly and in an interactive and interregulativemanner, and thereby function as a single apparatus having continuity of organization and action.

Also, one object is to furnish an improved rimary airlift, or single system-member, or use as one member of the described airlift pair, and to provide this primary member with a structural arrangement or means constituting a combined de-aerator and kinetic-energy converter, whereb an initial uptake column of aerated liqu1d,during a normal operation of the system,-shall be laterally enclosed throughout the entire height thereof, within a conduit which includes an upper conduit-portion or length wherein the de-aeration is normally effected in conjunction with a utilization of "the kinetic-energy of a spouting column to form and maintain (during normal operation) a super-head pressure transmittable as a contlnulng force and with a plus-atmospheric pressure, to a next succeeding airlift memer of such a pair, and thence in the same manner to a next following airlift of a multiair system. Thus, as hereinafter more ully' explained, the apparatus comprises means for transforming the kinetic energy of the discharging water and airinto pressure and thereby conserving, or restoring, a part of the head otherwise lost; and transforming into actual head such energies as are latent in, or result from, the disturbances incident to the de-aeration process and to the transferring of the liquid from one airlift-member to another of them in a multi-stage system.

A further object is to provide a peculiar and perfected organization of the said appai ratus and elements thereof, in which those elements, including the several conduit members appurtenant to the apparatus, shall be so connected into one continuous but multistage system, and shall be so coactive in this system for the inter-regulative control of the operation thereof, that the liquid may be air-lifted to relatively great elevations by short stages comprised in the single and continuous uni-flow stream, and shall thus operate with an economy incident to the use of low-pressure air, and also so operate without the loss or discarding, at any point, of any increment or residue of un-utilized air-pressure, and without the employment or aid of any mechanically-operable floats or valves, or other movably-acting regulators or stream-controlling devices, whether or not adapted for directly or indirectly affecting either pressures or stream-flow.

While the various phenomena involved in or incident to the operation of the system, or to the operation and interactive regulation of the airlifts comprised therein, or to the several components and devices appurtenant to those airlifts, may not as yet, or in all respects, be fully known or understood, nevertheless, from a considerable experience with airlifts as employed in mines, and from special investigations and practical tests of the present improvements, it is believed that the following description properly explains the nature and mode of action of this unitary airlift system and of the several elements thereof, in connection with the accompanying drawings, in which Figure 1 is a side-view, or elevation (assumed to be drawn mainly insection) illustrative of a two-stage airlift system arranged and operable in accordance with the present invention. In this view, for con- .venience of illustration, (and following a conventional practice), the longer tubes and conduit members are shown greatly reduced in length in proportion to their diameters, as compared with the relative lengths and sizes thereof heretofore more commonly used; this expedient is deemed to be necessary in order to more clearly represent the relations of the several elements in a preferred organization thereof. For instance, the diameter of ipe B is here shown having a diameter 0 nearly one-twentieth of its length, Whereas in practice said diameter often ma be only two to four inches, though 1n some 1 instances very much larger,--while almost any length may be used; lengths of from fifty to one hundred feet are sometimes employed, depending upon the conditions and requirements in any particular instance.

Fig. 2 is a side-view similar to Fig. 1 (but drawn on a smaller scale) for showing the same general arrangement when this is extended into a three-stage system having the component air-lifts thereof positioned, equipped and connected for an automatic and interactive regulation. 7

Fig. 3 is a side view analogous in arrangement to Fig. 2, for more fully illustrating the method of operation of the system and the principles thereof; and, for explaining the several coactive means and functions whereby there is obtained an inter-regulative control which extends throughout this multi-stagc apparatus.

Fig. 4 is an enlarged and more complete view of the upper portion of a primary airlift of the form shown in the preceding views, and illustrates certain relations and phenomena as hereinafter explained, regarding the spouting-column and the peculiar method and means provided for utilizing the kinetic energy thereof while maintaining a uni-flow stream, and whereby said upper portion becomes an energy-converter and operates in the multi-stage system as an economizer-regulator.

Figs. 4, 4", 4 and 4 are a series of diagrams supplementing Fig. 4, and further illustrate functions hereinafter explained in connection, more especially, with Figs. 3 and 4.

Fig. 5 illustrates how one detail of the apparatus may be modified in ways and for purposes as hereinafter set forth.

Similar reference characters designate, or indicate like parts or lines, in all the views.

In the arrangements of air-lift apparatus shown in the drawings, successive uptake columns are desi nated. in the order of their action, by B 13 and B, respectively; and, the respective submcrgence containers therefor are designated by D 1) and D. This container, or receptacle, for uptake column B may consist, as here illustrated, of a pit, or well, B, into which the liquid is collected and in which said column B extends downwardly in a manner commonly employed in locating ordinary air-lift in mines; the height of the submergence is here indicated by the water-surface line 4. For the uptake columns B and B submergenre containers in the form of tubular columns, as D and D", are deemed to be preferable, these being suitably positioned and connected substantially as indicated.

Said uptake column, or pipe, B, is considered to be the primary uptake column, since this initially receives all the liquid to be elevated; and when deemed to be desirable, the liquid may be supplied to this column, ii. by a tubular form of submergcnce container, such as l), which thus becomes an equivalent or substitute for this purpose, of the shaft or well I).

In practice, the several tubular columns, and the accessory devices therefor, may be supported by any suitable means, such as foundations and retaining members (not herein shown), thesebeing arranged and connected in accordance with principles and methods already well-known in the art of pumps and air-lifts; but, to simplify the illustration of the principal elements and features, those ordinary means are not herein fully shownor described. r

In some instances a single arrangement of the air-lift may be used, this comprising a primary uptake column, as B, and having suitable submergence-supplying and airsupply means therefor. This single airlift, when equipped and arranged 'in accordance with the present invention, will be provided at the upper part of its said uptake column, with an energy-converter, and, preferably, with a supplemental-head-conserving means, these two devices being illustrated, each in a preferred form thereof, in Fig. 4 and Fig. 5, respectively, and hereinafter more fully explained.

enerally, however, in order economically and practically to meet the more usual present-day requirements, it is important, and often necessary, to employ a plurality of airlifts arranged in series, and thereby deliver the liquid to a considerable elevation. In Fig. 1, the present improvements are shown thus applied to a two-stage system in which the liquid is conducted in a uni-flow stream. In this arrangement (Fig. 1), the submergence column, or well, D and connected uptake column. B are comprised in the first air-lift; and, the tubular submergence column I) and connected uptake column B are comprised in the second air-lift. These two air-lifts, each connected and furnished for co-active and inter-regulative operation, together constitute one air-lift pair, as hereinafter more fully explained. V

The system illustrated in Fig. 1, is shown in F ig. 2 extended into a three-stage system, this comprising three air-lifts, or airlift-members of the series. Each of these air-lifts comprises an uptake column and a submergence container therefor; and, all are connected and furnished for coactive and inter-regulative operation similarly as described in connection with Fig. 1. As in Fig. 1, the column B is here the primary uptake column of the first airlift-pair, and the submergence is shown to be obtainable by extending the column B downwardly in the liquid-collecting well I) to a proper disstance below the line 4, which (as in Fig. 1) represents a normal water level. Also, in Fig. 2. the entire m-ulti-stage system is indicated, by the walls 5 and 5', as being located mainly below a groundsurface line 6 and in a shaft or chamber analogous to those common to mines and quarries.

In the present multi-stage system, the entire apparatus may be regarded not merely as a series of individual air-lifts peculiarly connected for coactive operation, but also as a single air-lift in which one stream is successively actuated, and in which successive portions of the air-lift structure so control ,the.operation of successive portions, respectively, of said single stream, that these stream-portions become the operating instrumentalities and coact with and upon each other for effecting the inter-regulative control of all the stream-portions, and thus of the stream as a whole.

Before proceeding further with detailed explanations of the foregoing features and of their modes of interaction for effecting the inter-regulative function, some incidental matters should be noted The function of the air bubbles being to lighten the liquid content of the up-take column, so that the weight thereof will be over-balanced by the weight of the submergence head, it is obvious that any available gases may be used in place of atmospheric air, and hence it is to be'understood that the 'term air is herein employed as a generic term for designating the air or other gas which may be in any given instance available for use, or be used. in effecting the necessary reduction in the weight of the fluid contained within a given length of an uptake pipe.

The aerated uptake stream on passing above the upper end of an uptake pipe, issues as the spouting column, and the process of de-aeration is only completed at the upper end of this column, and within the energy-converter apparatus, as K.

The term spouting head is intended to refer to the height of liquid contained in the spouting column, if this liquid should be considered, or measured, by the reaction effect or pressure thereof downwardly at the level of the discharge end of the uptake pipe. For instance, supposing that the spouting colmun (see Fig. 4) might have I an extreme height of seven feet, but contain such a quantity of air so distributed therein as to have a pressure effect at said pipe-end level only equal to a liquid column three feet in height, then this head of three feet would be the spouting head, and would represent the pressure effect transmissible for producing a supplemental head in the Tq bmergence column of a next following air- In the practical operation of an ordinary airlift series, sometimes the working conditions will be modified in such a manner or to such an extent as to change the rate of upflow,-that is. the rate of action. or discharge,and thus for "a time cause some one of a series of the ail-lifts to have an undue excess of action as compared (at such a moment) with another of them. These variations, sometimes, heretofore. have been regulated by means of mechanically-operable govermng devices applied to the several component air-lifts of such a series. the present system, however, no such governing devices are required, owing to the interactive control by which the heads and pressures are now made conjointly operative and inter-regulative, for thereby effecting the necessary control by an auto-governing action which extends to the system as a whole, and also applies to each of the individual airlift-members thereof. These results are now attained, as hereinafter explained, by means of a combination of coactively-operating structural features which has the function of an oscillation governor, said features being arranged for restricting,or rendering less active than otherwise would be normal,-such oscillations of pressure and flowage as may occur from time to time, in either one or both of the airlifts of an airlift pair, and thereby accelerate the process of balancing, or re-balancing, an unequal operation of successive airlifts, (or of an pair of them), whenever either one of Sue i a pair may have been materially changed in its rate of action relative to the other.

The several uptake pipes,these being uptake-stream containers,are designated, (in Figs. 1, 2 and 3), by B 13 and B for indicating the respective positions in the system of this series of similar members, of which one may be designated individually but without choice, as the pipe or column B. In like manner the submergence columns may be designated individually but without choice, as column D; and, the

.members K K K, may be so designated by K, and especially in connection with Figs. 4 to 4" inclusive. On the same principle, any one of the aeration nozzles may be referred to as nozzle N, and any airsupply pipe therefor, as pipe t; and similarly, any of the columns-connecting conduits, or ports p, p", may be designated by P whenever this may be sufficient, or consistent in view of the context; this method may also be extended to other details common to a plurality of the air-lifts of the system. 1

In Fig. 1, the uptake column, B, is shown provided with a stream-conductor pipe, P

shown in a sub-surface position, for thereby] transferring the uni-flow main-stream for one to a next following airlift while this stream is maintained at all points under a plus-atmospheric pressure. This plus-pressure, in practice, preferably should be greater than the pressure-variations liable to occur within the uptake and submergence columns by 01' during the coactive operation thereof; hence,as hereinafter explained,the submergence super-head should be of suflicient height and quantity for effecting this result. Above, but adjacent to, said stream-transferring conduits or passageways, P}, P said uptake columns B B are shown each provided with an apparatus having the function of an energy-converter, as K and K respectively, each of which forms the upper-end portion of an uptake column. This device, or converter, has the function of a de-aerator, and operates to produce the submergence superhead, as 72 a preferred form of the apparatus being hereinafter more fully explained, particularly in connection with Fig. 4.

The uptake columns, B B B are shown in the accompanying drawings as being each provided at the lower end thereof (see Figs. 1 and 2) with an aeration device, or nozzle; thus the latter term is here used generically. These aeration devices, (whether or not having the usual form of a nozzle), are symbolically indicated at and by N, N and N respectively, and in practice any of the well-known kinds of stream-aerating devices, or air-lift nozzles, may be adapted and employed for the present purposes. The nozzle at N operates to initially aerate the stream when this is entering column B, and A the nozzles at N and N operate to re-aerate the same stream (subsequent to a de-aeration thereof) at successive points in the uniflow course, or path thereof. In Fig. 3, these several nozzles are presumed to have effected such aeration (each at its respective position) at'and upwardly from the lines 7 7, 7 respectively (Figs. 1 and 2).

For the purpose of supplying the air to the nozzles, the present air-lift system may comprise, as an element thereof, any of the well-known arrangements of air-supply apparatus such as already employed in ordinary air-lifts. For instance, as indicated diagrammatically in Fig. 1, the uptake pipe, or column, may be suitably air-supplied by means of some ordinary air-compressor, as of suitable location and capacity, and which may be connected by air-distributing pipes t t, to the aeration devices or nozzles at N N N, for the uptake columns 13. B B respectively. These air-distributing pipes are shown supplied, in Fig. 1, by a main pipe, t, leading from compressor C; in Figs. 2 and 3, the pipe t is supposed to come from an air compressor not shown in these views. For regulating the action of the several nozzles said air supply pipes may be each provided (at some. or any, convenient point therein) with an ordinary flow-adjusting valve or regulator, as ind cated at V V (Fig. 1), respectively; also the compressor, or a pipe as t, therefrom, may have a main-valve, as at V, whereby to regulate, and to let on or cut oil, the whole air-supply at once. However, in some instances these valves may be omitted (as for instance in Fig. 2) if the pipes are ample, the nozzles sufficiently uniform, and each 7 nozzle accurately located at a proper relative elevation. i

For convenience of description, and to facilitate elearness of illustration, the several principal members of the airlift pair have been shown in Figs. 1, 2 and 3, arranged side by side and at relatively considerable distances apart, but it should be understood that in practice, whenever found to be desirable, the several members, and especially the uptake pipes B B and the submergence columns therefor, may be placed close to each other, or even more widely apart, according to the conditions attending any particular location or the preference of the constructor. One effect. evidently, of placing pipe B and said column D close to each other, is to shorten the distance through which the counter-flow stream has to travel in passing from the tie-aeration chamber, as K laterally through port P and into said column D an illustration of one such close form of assemblage is shown in the small sectional side view, Fig. 5.

By extending this uniflow system from a 100 single airlift-pair, as in Fig. 1, to includethree successive air-lifts, as in Fig. 2, a further and important improvement is thereby accomplished, since, in this more extended system,-the plurality of three coactively- 105 connected airlifts not only comprises three column pairs (each forming one air-lift), but also comprises a plurality of airlift pairs.

For instance, in Fig. 2, (also in Fig. 3), 110 the three single airlifts are arranged first, into two pairs, and these pairs are arranged with one air-lift member common to both pairs. The primary airlift D B is arranged and connected for delivering liquid 'to a second airlift D B that in turn, de-

livers the same liquid to a third airlift, D B Thus the series of three airlifts is here shown arranged in two successive pairs, in which the secondary airlift, as D B of the first pair is also the primary airlift of the second pair; all three of these airlifts are herein indicated as being arranged,in this instancefor operation by air of the same pressure. Also in this triple system, there are two of the energy-converter apparatuses which are also herein described and designated as a combined energy-economizer and oscillation governor. These two apparatuses, as K K are shown coactively connected each with other through an intervening uptake column, as B (Fig. 2), which is operated by a submergence, as D that is supplied from said precedin uptake column 13, and is in part regulated by means of the first of said combined apparatuses; this auto-governing mode of action (heretofore mentioned) is hereinafter more fully explained.

In said triple-arrangeient of Fig. 2, each of the uptake columns operates under a different condition from the other two. In the first airlift, said column B is supplied from a normally fixed submergence level, as 4, and discharges against a spouting-column head (in column K that is subject to a governing action; in the second airlift, the uptake column, B is supplied from a submergence column D which is subject to a variable but automatically-regulated pressure or head, and discharges against a spouting-column head, (in de-aerator column K in the same manner as said column 13, just described; and, in the third airlift, the uptake column, B is supplied by and from a submergence column, D arranged and operating similarly as the column D just described.

Thus the said series of airlifts, while each have distinctly different operating relations from the others, are interactive and adjunctive each with the other two, and therefore are subject, individually and as a system or series, to the aforesaid auto-governing action. Each said airlift of the system, thus may be said to have an individual and primary mode of action normal to its own features and proportions; next, the successive airlift pairs have each a mode and ratio of action, or operation, which may be said to comprise those individual actions plus a varlation arising from their interconnection, whereby a change of operating condition obtaining in one member of said pair, acts from time to time, to accelerate or retard the action or ratio of operation of the other said member of the pair. This complexity of the relations and functions, is further increased in the present series-system, by the inclusion therein of a plurality of the sensitive and quick-action apparatuses K, each operating as a combined energy-economizer and oscillation-governor.

In the three-stage system shown in Fig. 2 (also in Fi 3), the second air-lift of the series may lie said to be, and is herein regarded as being, one form of a stream-impelling connector for receiving the uni-flow stream from the first air-lift and transmitting this stream (as an unbroken mainstream) tothe terminal air-lift (here the third one) of the system. Said intermediate stream-impeller is also here shown fitted and proportioned for operation as a second airlift of the system, and for being operated by the same air-supply pressure and submergence-efl'ect as employed in the first air-lift column, B, andin the third air-lift column, B, of the system.

However, this three-stage system may be arranged in some instances for using such an air-lift form of intermediate impeller when this is proportioned for elevating the stream through a different proportional distance, or height. This arrangement of the system to use unequal'lifts for successive and coactive airlift-members, will be obvious without being herein specially illustrated, and it may be so used advantageously in various locations. In such an instance, it is necessary, of course, that the successive uptake columns, respectively, shall each be provided (or connected) with means for suitably regulating the pressure and volume of the supply of air thereto; for this purpose an ordinary arrangement of compressor,

pipes and valves, (such for instance, as

herein described in connection with Fig. 1), will usually be ample for such requirements.

When the liquid-aerating air-jets are forced through an ordinary perforated nozzle, (symbolically indicated at N unde a pressure somewhat in excess of the pressure normally or actually necessary to effect the required proportionate aeration, these jets frequently operate in practice, after the manner of injectors and thereby impart power, or energy, to the up-flowing stream and thus produce an upward movement or velocity of the stream in addition to the rate of up-flow due to the aeration itself. While this injector-effect or jet-action may, usually, be the cause of loss of power under the former practice. this action normally has a useful effect in the present system, since, by its increase of the range of normal action, it thereby lessens the danger of having an air-lift cease operating, or becoming stalled,because of a temporary and small deficiency in the degree of said aeration. This useful effect may now be *advantageously and fully realized owing to the effective manner in which the energy of the spouting column,including said I injectorefiect or energy,-is converted into pressure in the energy-converter member, as K or K of an uptake column, as B or B. For this purpose said converter member should have the laterally-enclosed de-aeration column or chamber thereof, of a sufficient height, and otherwise be proportioned and have a capacity, ample for treating the normal spouting column when this is moved up in said member, as K by a distance, or extra head, corresponding to said injectorefi'ect. Thus it now becomes practicable to use an excess of injector-force, with an ample aeration, and also to use a full measure' of submergence, thereby insurin a more advantageous operation as a who e, since ill ing manner.

all the excess and residual energies so trans mitted can now be effectively converted into a pressure which acts to raise the submergence superhead to a height compensating for these, otherwise, cumulative losses.

In this connection it will be remembered that in ordinary airlifts having a singleli ft uptake pipe, when the aerated liquid emerges from the discharge-end of this pipe, the air content thereof expands instantly while the liquid content flows out, usually in a spurt- Thus the de-aeration is there effected in a relatively violent manner, and whatever kinetic energy is contained in the out-pouring liquid of the spouting column is lost, only the liquid itself being saved. Contrary to that method and practice, in my present improvements the aerated liquid of the upflowing stream is closely retained in a columnar form or status until the upfiow movement ceases and the de-aeration is completed, and at this time only the separated air is discharged at the top. while all the liquid is returned downwardly for a distance, and then is disposed of by and in a flowing stream and without any Spurting or overflowing action, and hence with no loss of energy consequent thereto.

Thus, by means of my present improvements, the total efficiency may be increased by operating the primary airlift in a manner which otherwise would result in a loss. To thus increase the efficiency of the operation in the uptake pipe B, necessarily (under the practice hitherto) increases the loss due to the discharge of an unduly large quantity of energy in the spouting column. But, by the conversion of the spoutingcolumn energy into a coacting pressure. that loss is retrieved, and is then made available and effective for increasing the otherwise not efliciency of the airlift pair, and of the I multi-stage system, considered as a whole.

From the foregoing description as illustrated, it will now be seen that in an interconnected series of three airlifts, (as in Figs. 2 and 3) each of the uptake columns has a different operative relation in and to the system. The first said column, B initially receives the liquid, and hence may take up more or less in quantity, in a given unit of time according to variations in the operation conditions; the third said column, B receives only the discharge from the second airlift, and discharges that quantity not to be used again in the system; and, the

second said column. B operates only as one member of an airlift-transmitter intermediate to the first airlift and said third one, thus receiving whatever quantity is supplied to it, and delivering only this same quantity to said third airlift.

However, owing to the herein described interactive method of regulation, the first airlift cannot continuously over-supply the second airlift, since at the beginning of such an action, the immediate effect thereof is to check the rate of action of the first airlift and thereby prevent a continuance of such an over-supply; this result, however, may be modified to some extent, and within the range of normal working conditions, by some degree of increase, for a brief period, in the rate of action of the second airlift. On the same principle, but in a modified manner, the third airlift normally operates to check the rate of action of the second airlift, (but in some cases to permit acceleration thereof), should the latter tend to strongly over-supply the third air-lift.

Thus the second airlift may be restricted or regulate the rate of action of the first one. Also the first one may be restricted in action, or released to act more freely, but the action of the second airlift after this second action has been modified by the third airlift; in the latter case, said restriction or modification of the action of the first airlift results from a conjoint action of an airliftpair which comprises said second and third airlifts of the system.

In Fig. 3, the third uptake column, B is shown elevated (above its otherwise normal position) to a position for securing the gain equal to the sum of the two supplemental submergence-heads 7L and [L2 of the two submergence columns D and D respectively, these gains being obtained from the conversion,as already eXplained,-of the kinetic energy in the spouting-columns. Thus, said energy transferred to submergenc'e column D permits column B to be placed higher (than otherwise normal) by the pressurehead height h and, similarly, column B may be placed higher, by the amount of head, or height 7L2.

In this connection it will be remembered that in an air-lift uptake-pipe, the up-flowing stream comprises two elements or currents, one being a liquid stream-component and this being aerated by the stream of air. This air, however, is normally in a comminuted form, or in bubbles, which not only move upwardly with the liquid stream but also have a further upward or floatation movement in (and relatively to) the liquid, and commonly designated as slippage. In practice, the rate,or velocity thereof relatively to the liquid,-of this slippage of the air bubbles necessarily varies, and may arise from various causes; also the rate and extent of their coalescence similarly varies. Also, these variations may occur from time to time, (from moment to moment), not only in the rate of slippage, but also of the proportionate volumes of air and liquid contained within or delivered by an -uptake pipe, and thereby produce variations in the rate of stream-flowage, and in pressures (at some points or heights within the columns), which are in the nature of fluctuations, or, as herein considered, oscillations, either incipient, initial or resultant in character. These phenomena also have to be considered in connection with the normally rapid acceleration of the aerated stream during the ascent thereof within the uptake-pipe, and in accordance with a well known principle.

Thus it appears that the formation of a spouting column of aerated liquid, takes place in connection with a peculiar changing condition of the mixture of air and liquid during the upflow thereof within the uptake pipe. Owing to said slippage of the air bubbles in the liquid, and the normal and well-known tendency of a stream to flow faster in the central portion as compared with the velocity thereof in the outer or peripheral portion, there is normally a constant coalescence of the bubbles by the combining, together of several into one, thereby increasing their size and consequent rate of slippage, in accordance with a well-known principle. Then, too, such a large bubble,- since its slippage increases rapidly with its enlargement,overtakes and gathers into itself more and more of the smaller bubbles, so that in long uptake pipes these losses may (and often do) represent a large waste, in the aggregate, of power and efiiciency. further result of that action is normally to segregate the air more rapidly,and'with a centralizing flow thereof,-near the upper end of the uptake pipe, so that the upflowing column when nearing the discharge end of said pipe may have an outer portion, or peripheral zone (as it would be seen in a cross-sectional view of this pipe) composed of liquid nearly or fully de-aerated; this outer portion, evidently, will tend rapidly to form and thicken around the highly aerated central portion, so that on emerging from said pipe discharge-end only a moderate proportion of the total quantity of liquid may be projected up, as a spouting column, into the converter chamber of the apparatus K.

Having in mind Fig. 3 and the foregoing explanations, it will now be seen that on entering the open lower end of uptake B, the liquid stream is aerated in the usual manner by air under a suitable pressure and supplied through an aeration device, as N, (at level 4), and that being thus aerated the stream is pushed up by submergeneeeffect (approximately indicated by D) toward the upper discharge-end of said pipe, at line 8, (Fig. 4). During the upflowing movement of said stream, the air-bubbles rapidly expand, and the velocity of up-flow correspondingly increases upwardly from said point of aeration, while the pressure proportionally decreases; also, the coalescence accelerates on nearing the said upper pipe-end, whil a substantial, or relative, de-aerating ac ion normally proceeds in a peripheral portion, or zone, of the pipe, and thus tends to rapidly form, or develop, a stream-segregating action, so that on reaching said discharge-end of pipe B the main-stream may be regarded as comprising a peripheral de-aerated stream (or one of low aeration), which surrounds a central stream in which an excess of aeration has a high flotation velocity and is concentrating with an accelerating coalescence. Thus, on passing said line 8*, the said peripheral stream,this being here practically deaerated and of a uni-flow character, readily passes outwardly over the pipe-end (at arrows 1' Fig. d) and thence, (as a branch-portion of the main-stream) flows directly to the transfer conduit, P Simultaneously with that action, the new highly aerated central stream flows upwardly (as another branch of the main-stream) in the form of a spouting column which enters with a high velocity the top-vented column of said apparatus K and therein becomes fully de-aerated, while the liquid thereof is forced outwardly to the enclosing wall, and there is formed into a down-flow stream which on or before reachin said transfer-conduit re-unites with. said peripheral A stream thereby forming a restored and deaerated main-stream which flows through said transfer-conduit for supplying the next following submergence-column, as D Thus, it will now be obvious that in the apparatuses K, the de-aeration up-flow and down-flow stream (the latter being the counter-flow one) may be properly regarded as a branch-stream Which comprises only a portion of the main-stream of liquid issuing out from the said upper pipe-end of column B, and of which a main,or primary,portion which is substantially unaerated flows directly from said pipe-end, and thence passes forward to the conduit port 1?, and thence into the next submergence column as a continuous uni-flow current. The liquid of said branch-stream is also a stream of a uni-flow character, since this liquid is only diverted temporarily from the main stream-path, (and then only for being segregated from air temporarily associated therewith) and is at no time released from its energy-converting control, but is immediately (and in a continuing manner) re-united with the said main or primary stream-portion, and is then incorporated therewith into said next followlng liquid submergence-column.

In the upflowing fluid column within pipe B, there is normally a continuous acceleration of the whole stream or fluid column up to line 8, (see Fig. 4). In this column below line 8, the air-content of the stream accelerates more rapidly than the stream as a whole, owing to the described slippage of the air bubbles in the liquid. Accordingly, it may be said that up to said line, or level 8, there is a constant acceleration of the liquid-content, and a greater ratio of acceleration of the air-content of the stream. This relation, however, of the said two velocities or accelerations, is changed when said aerated stream passes above said level 8; from this point the ascent of the air content continues to accelerate while also undergoing an increasing rate of segregative action, whereas during this same period the upward movement of said liquid-content constantly decreases, until it finally ceases in connection with the formation of this liquid into a counterflow stream.

In the operation of this apparatus (see Fig. 4) functioning as an energy-converter, or as a kinetic-energy economizer, the tubular member K, first receives (directly from pipe B), the described excess aerated central stream in the form of a spouting column, together with all (or nearly all) the energy therein, reduces in succession the liquid. increment-s thereof to a state of rest, and then progressively incorporates them into a counter-flow stream, and later delivers this (in some or a sufficient part) through said transfer-conduit, P, to supply, (or re-supply, as the case may be), said pressure-head in submergence column D. Thus, it may be said that the energy discharged out of an uptake pipe, B, with the contents of a spouting column, is economized, (instead of being dissipated or wasted. by being applied to the useful purpose of increasing the pressure-head. of the submergence for the next following airlift. This direction of the action, however, is considered as being reversed as regards the same member K of the airlift-pair member, when a particular governing action, or impulse, is initiated from or by a next following uptake column, as B in Fig. 3. These functions, and the results thereof as regards the governing effects, will now be described more in detail, as follows Referring to Fig. 4, this enlarged and sectional view illustrates in a diagrammatic manner a preferred arrangement of the apparatus K, and the principle and mode of action thereof, as the same are now understood. The uptake pipe, or column, B, has the discharge-end thereof terminating on the line 8*. This pipe-end 8 constitutes one channel comprised in that portion, or structure, which is herein sometimes designated as the three-channel-junction, and of which the aforesaid conduit or port, P, constitutes a second channel, and of which the lower portion, F, of the de-acration chamber, constitutes the third channel. These three channels. 8*. P and F, are preferably connected by, or may comprise. 51

chamber, F surrounding the pipe-end 8 and proportioned for certain coactive functions as hereinafter explained.

Within the opposite side-lines, 3, 3", of the tubular wall of member K, the two curved lines, 6 b are drawn for indicating a central zone Z and a peripheral zone Z Said lines b are also shown extending well down into the pipe B, for there indicating a downward extension of said zone Z within a surrounding zone, Z that is wholly within uptake pipe B; in this zone, Z the tubular or peripheral, and substantially de-aerated, upflowing stream of liquid (already described) is represented by arrowlines 1*, 1' This stream, 1, on reaching the aforesaid level 8 normally flows outwardly and then downwardly, over and around the pipe-end 8', (as clearly indicated by the curved arrows at 1 T and thence flows through chamber F and conduit P, into the submergence column D, as also indicated (in a customary manner) by successive curved arrows. Said peripheral stream, 7*, being thus diverted directly into the main flowage path of the uni-flow mainstream, the described central,and now excess-aerated stream,here indicated by the single line of arrows, 7' ,-is free to shoot upwardly through said out-turning portion, 1, of said peripheral stream and then spread out as indicated by the outwardly-curved portions of said lines 6 6 (between the horizontal lines 8 and 8"), and thus pass upward into the columnar de-aeration space F On thus issuing from pipe B, said highly aerated. central column, or stream, now shoots upward as a spouting column, and with a velocity, and to a height, due to the kinetic energy therein; and, during this upward movement, the air-content rapidly expands and segregates, while the liquid-content is correspondingly de-aerated. These operations tend to disperse said liquid outwardly,about as indicated by a series of arrows from r to r ,and thereby form of this liquid a peripheral down-flow stream indicated by the line of arrows 1", 7': these arrow lines also indicate how the said Squidcontent of the spouting column, after deaeration thereof, is formed into a peripheral and counter-flow stream which passes down ward within the walls 3, 3 and into the space F and there re-unites with said peripheral stream, 1' from the pipe zone Z and from thence passes through conduit P into the submergence column D. While the spouting-column is thus flowing upward, it is continually and progressively de-aerating.

These processes being continuous (during operation of the airlift) there seems first to be formed a de-aerated film or sheet of liquid (on or near the inner surface of the tube) which flows down. (as indicated by said arrow lines r", r) with a gradually increasing thickness until it enters the passageway space at level 8 in the form of a counter-flow stream. At this time and position, therefore, the quantity of such downflowing de-aerated liquid corresponds with the quantity of spouting-column liquid flowing upwardly (at level 8*) from within the discharge end, 2, of pipe B. Thus one result of the apparatus in operation, is to form the counter-flow and pressure-head stream equal in volume per second (or unit of time) with the stream of liquid in the spouting column at the base thereof, this base being at level 8; also, to effect the de-aeration and energy-conversion simultaneously.

It Will now be evident that the primary airlift of an air-lift pair, comprises means for laterally enclosing the uptake stream, or column of aerated liquid (when this airlift is operated with a submergence normal thereto) throughout the entire height of this stream or column, this height including an upper-end portion or zone which begins at the upper end of said uptake pipe, 13, and extends up to the point where de-aeration is accomplished and upward movement of the liquid'ceases. In this zone, the liquid gradually separates from the air, and is laterally transferred and formed into a new and different stream which consists of liquid flowing downwardly by the force of gravity, and thus constitutes a counter-flow stream. And this counter-flow stream after passing down to a position where the liquid thereof is substantially free from contact with, or the effects of the up-spouting stream (from pipe B), may then be said to pass through the port P and enter the submergence column, D, as a resisted sub-surface current, since this stream enters below the upper surface of the liquid submergence column, and is thus resisted by a force resulting from the head of such column, this head being normal y of a height between-lines 8" and 8, Fig. 4.

Thus. in the manner described in connection with Fig. 4, the kinetic-energy, or vis viva, of the spouting-column becomes converted into a pressure which reacts downwardly for transmission by way of a fluid connection below said level 8*, and to a next following airlift. This reaction-pressure, which may also be designated as the conver sionpressure,--is thus transmitted as an increment of head, which is so applied, and this in such a direction, as to augment the normal head of the submergence column of another airlift-member of the system.

The height to which, in practice, said spouting column will ascend within the deaeration tube (or tubular chamber) as K, Fig. 4, will be through such a distance (disregarding friction) as will absorb, or represent, the amount of kinetic energy possessed by, or residing in, the aeratedfluid at the time this passes above the said level 8. Thus said energy, or vis viva, becomes converted, and utilized in the production of apressure which closely corresponds with the downwardly acting force or weight, of the spouting column, this force constituting a reaction-pressure as already explained.

Because of this effective utilization of said kinetic energy, ,itnow becomes economical to provide, (in said primary airlift of the pair) for the use therein of such a volume of air in proportion to the volume of liquid taken in at the inlet N (Fig. 3), and for supplying this air at such a pressure as will produce a relatively rapid upflow in the uptake pipe B, and thus (according to a well-known principle) minimize the loss of power resulting from the upward flotation, or slippage, of the air in the liquid during the passage thereof upwardly from said nozzle or jet N, to the discharge level at.8, while correspondingly increasing the quantity of said energy as discharged in and with the spouting column.

The total head, which, in the primary uptake column, is functionally effective (for determining the height of the submergence in the secondary airlift) includes the entire heightof fluid, from the lower end at the intake level at 7 (Fig. 3), up to the topof the spouting column. Thus the weight or pressure which as a resistance has to be overcome by the submergence of the primary airlift, consists of the fluid in pipe B plus the additional weight of fluid in the spout ing column within the (lo-aeration tube, K. In this total uptake head, the fluid, after being elevated by the combined action of aeration and the submergence, is not discharged from the upper end of said uplift distance, but is drawn ofl' at a point (at a sub-surface position) intermediate to the submergence level and the top level of the uptake column. And. in connection with a final de-aeration of the liquid. the air and the liquid,instead of being discharged together in the ordinary way,-are now discharged separately, the air being released free from pressure (except the atmospheric pressure) and the liquid being drawn off de-aerated and under a substantial amount of pressure in excess of atmospheric pressure.

For more fully explaining the complex relations, and the methods of coaction, of the energy-converters, K, and for further illustrating the principles and the governing function thereof, reference is made to the series of diagram, and small-scale, views, Figs. 4 to 4 inclusive, supplemental to Fig. 4. In each of these supplemental views, the said apparatus is assumed to have the same detail construction and arrangement as already described in connection with Fig. 4, so that the several structural details thereof (so far as here shown) may be recognized without being here all desig nated by reference characters, nor again particularly described.

In Fig. 4*, it is assumed that the apparatus is operating in a uniform or balanced manner; that is, the discharge of liquid upwardly from pipe B (arrow r corresponds in volume with the down-flow of liquid in s1duncrgenre-rolumn D (arrows r) at a point below the level of the transfer-pipe, or conduit, P. Under this condition. the stream-flow from member K into column D. may be represented by arrows r 1'. of which the latter, 1', turns down into column l.) for thereby indicating the course of said flowage.

It is also assumed, in Fig. 4. that the spouting-column-head extends up to line 8 (this line representing atmospheric pressure), and the super-head resulting therefrom is also here shown positioned above the path of main-stream flowage, and as extending in column D, up to the same line, 8: this super-head, S is also indicated by shading just below, and extends up to, said line 8", and is now normally stationary. If, now, the submergence height in column 1), normal to uptake pipe B,-when this dis charges at line 8,be considered as coming up to said line 8*, then it is seen that the weight of super-head S is supported above and pressing upon down-flowing stream S, in a manner clearly indicated by the opposing arrows 1' and 1- which indicates, respectively, the upward resistance (arrow 1'), and the downward pressure, or weight, (arrow 1 of-super-head 8. Thus. in Fig. 4*, the stream flowing through conduit P enters column D under a super-atmospheric pressure equal to atmospheric pressure plus a pressure represented by the. height of super-head S measured upwardly from said conduit P. i

In Fig. 4", the operations in member K, and the supplying therefrom of liquid to column D, are assumed to be the same as above described in connection with Fig. 4*. excepting that the down-flow of the liquid submergence-column S has been accelerated to the extent .of taking the same quantity through conduit P and also drawing down some liquid from the super-head.-here designated by S -until this super-head has been. lowered from said line 8 down to the level 8; this head-lowering movement is here indicated by arrow r". An immediate and normal effect of thus lowering said superhead is to reduce the pressure-resistance to the described stream-flow through conduit P; and. if this reduction should he continued for more than a relatively momentary period. the spouting-head height. in converter K, would be lowered by an it raising) of the surface level of the submergence super-head as above described. may readily occur in practice from various causes; as, for instance, from a stopping up of one or more holes in the liquid-aeration means. or as a result of some abnormal but temporary action in one of the airlift-members of a series of them. One such cause, usually quite temporary. may be an unusual degree of coalescence and the excessive rate of slippage consequent thereto.

In Fig. 4.said reactionary movement,- for restoring super-head S .is represented as having taken place. Assuming that the spouting-column (arrow 1") has a pressurehead extending up to line 8, that, at the be ginning. the super-head corresponds with S Fig. 4", and that the down-flow velocity of the stream (arrow r) in column D has been somewhat reduced, then the flow through conduit P naturally divides. the main portion.-as before.-flowing down (arrow 7") into column I), while a smaller portion flows upwardly (arrow 1'") to resupply the submergence super-head. here designated by S In this manner, the lowcred head. 3 of Fig. 4 is gradually (usually rapidly) raised from said line 8" up to line 8 .-as in Fig. 4,and, under the action of the forces and inertias then appertaining to the apparatus and the streams therein. the level of this super-head. S will normally be carried up to a higher level. here indicated by line 8 At this height. 8". the added weight tends to again accelerate the down-flow velocity of the submergence stream (arrow 7"). and thereby again draw down the super-head level toward line 8. thereby restoring the status represented in Fig. 4. and already described. Thus the described range of suecessive hea ds. from line 8" to line 8". may he said to constitute an oscillation in the operation of the apparatus comprising the energy-converter. K. and the upper portions of the columns B and D directly associated therew th. including the upper-end portion ofcolumn D which is the superhead container.

Tn practice. of course. the vertical extent of said oscillations necessarily fluctuates,

and these oscillations also occur with a variable frequency, depending largely upon the coaction therewith of operations simultaneously occurring in more remote portions of the system. Also, it will now be evident, the rate or rapidity of said action or movement for the restoration in height of a lowered supplemental head, as S depends in part upon the relative cross-sectional area of column D, so that by making this member somewhat larger than tube B, said rate of head-restoring action may be regulated, (within such limits as may be found desirable, in any particular instance), for inaugurating an acceleration of upflow in pipe B (by decreasing the columnhead-pressure resistance thereto) at a moment,or instant,slightly before said process of headrestoration can normally be completed. This over-lapping of the said two functional and successive but distinct operations, is deemed to be desirable as tending to restrain a too great, or a too rapid, lowering of the effective head of the spouting column while assisting this column by a raising thereof, (by a transference of liquid and pressure), and thus continue to completion the raising of said lowered submergence head up to the full normal height thereof.

Thus the apparatus when organized and aranged as set forth, provides for a highly sensitive mode of interaction which operates as a quick-acting governor, and thereby provides for limiting the oscillations of flowage, and of heads and pressures, in a most effective manner. And. the apparatus may be said to be also organized for regulating an intervening governing action by means of a supplemental-head chamber connected for direct coaction with the spouting-head during a time-interval following a change of flow in one uptake column, and prior to a resultant but in point of time, later and responsive uptake flow in the other said column, for thereby reestablishing without violent agitation, a balance of and between the operations therein.

Thus, in the time between an initial acceleration of upfiow in column D, and a corresponding or ultimately-resulting increase of upflow velocity in pipe B, there has been an intervening governing-action consisting in the instant lowering of said head S followed at once by a partial restoration thereof. Thus said initial lowering of head S and the inaugurating of the restorative operation therefor, maybe said to be preliminary to, and in point of time to functionally precede, the beginning of the ac celeration of flow in pipe B for producing a newly determined balance as between the flowage in columns B and D.

A further feature of this series-system relates to means,ap urtenant to the primary airlift and the submergence container, or

column, of a secondary airlift,proportioned for receivin and de-aerating the aerated liquid of said spouting column and for then distributing this liquid, each of these operations being continuous during the operation of the airlift pair. Said distribution is effected in a peculiar manner, being delivered (from time to time as required) in variable relative quantities, or proportions,according to inequalities in the operation of the two airlifts,in part to the upper end of said main submergence head (this end being at line 5*, Fig. 4), and in part to the lower end, (at line 5, Fig. 4), of the supplemental submergence head, (as S Fig. 4) which extends upwardly from said main submergence head.

This interactive operation of two said airlifts under said variable distribution of liquid from the spouting-column, operates in connection with the described oscillation of flowage and pressure naturally occurring in the uptake pipes and conduits, as a factor in that joint operation of the airlift pair whereby a non-normal operation whether arising in one or the other of the two airlifts, is transmitted and counteracted or balanced, for thereby and at once re-stabilizing a normal operation of the system following the occurrence therein of many material inequalities in the operation of the two airlifts.

An important feature and advantage of, and one which further distinguishes,tliis uni-flow multi-stage system, consists in its capacity, on being subjected to certain irregularities as regards the air-supply and other conditions, for operating temporarily in a reverse-to-normal manner, and for then automatically starting, or resuming (as the case may be) its normal and forwardlyacting mode of o eration. For instance, in pract1ce,especial in certain mining regions havin worklngs diflicult of access,- it has now become commercially important sometimes to supply the air through very extended pipe-lines from compressors located in valleys far below and Where waterpower is available for use in compressing the air by steam-power.

In such pipe-lines, however,even when these lines are quite moderate in length,- water is liable to collect at one or more points therein,from condensation or otherwise,and be carried forward in a violent and oscillating manner with the result of making the air-supply and its pressure fluctuate extremely at the nozzles of the air-lift system. Some water, in such an instance, may be carried forward to one nozzle and for the moment completely block the operation thereof, while, at the same moment, air may be forced through one or more other nozzles under an excess pressure, and thereby force air backwardly (through a lower colbers,-prepares umns-connection) and thence upwardly into a submergence column. I

This reverse-to-normal and temporary mode of operation, is briefly illustrated, but only in a diagrammatic manner,in Fig. M. In this view, the liquid stream in column D is indicated (arrow 1'") as having been reversed, and as having been driven up (arrow 1') to form a highly elevated pressure-head, S, which serves to temporarily store up a considerable quantity of liquid, while applying a heavy resistant pressure at the level of conduit P. \Vhen said head S has been raised high enough to fully resist the normal flow (arrow 1*", Fig. 4) from the member K, then a portion of the liquid flowing up in column D (at arrow 1-), will naturally be diverted (arrow 1*), and pass through conduit P, flow (arrows r") up into the de-aerating chamber of converter K, and thereby reach a point so far above line 8', as to press back (see arrow 1' the normally rising stream (arrow 1") in uptake pipe, B, and thus for a time stop the operation of this pipe as a liquid-supplying means,- this being here indicated by the opposing heads of arrows 1" and 1- within said pipe B. On this status of the flowages being continued for a time, the normal up-flow in pipe B may be chan 'ed to a down-flow, and thereby deliver liquid (supplied upwardly through column D) into the submergence column of pipe B. Thus, said back flow, if sufficiently continued or extensive, tends to conserve the contents so displaced, by shifting the same backwardly in the system, stage by stage, as far as may be required for the storin thereof, and thereby avoids a reduction of the liquid content of the system as a whole.

When there occurs a sudden back-flow of excess-pressure air, (as elsewhere herein explained) this back-flow normally operates to over-aerate the lower-end portion, and thereby raise the whole quantity of the liquid of said submergence column, but only to a height much less than the same uantity of air would normally raise the liquid in an uptake column, since the cross-sectional area of the submergence column (as herein illustrated) is made considerably greater than the cross-sectional area of the uptake column. This feature, and relationship, is deemed to beparticularly important. since it favors a backward flow of liquid through successive air-lift systemmembers, and thereby,thr0ugh themaintenance of a full suppl for these memthem or automatically starting to act in a forward direction at once on the air-supply subsiding to a normal pressure extending equally to all the aeration devices of the series. 1

Thus the present'system under normal conditions operates to forwardly actuate the stream by the uni-flow method, and under the described occasional and abnormal conditions, operates backwardly in a manner which, besides conserving the liquid contents, by a storing thereof, enables the system to immediately resume its normal operation on a restoration of a normal airsupply. Thus it may be said that the several. air-lift system-members are not only inter-regulative as regards their forwardlyacting functions, but also are inter-acting and inter-regulative as regards and during a temporary reversal of their normal mode of action, for thereby makin the s stem self-starting and self-regulating un er a wide range and variety of opposing conditions which otherwise would normally halt or defeat the operation thereof.

An analogous situation as may arise from the described use of said pipe-line air-supply, may also arise in some instances from other causes, as for instance, when the compressors are located near the air-lift system, and especially when, in this arrangement, the compressor is actuated electrically by conductors bringing the electric current from distant power plants. In the latter case, as is well-known, the power lines are subject to surging effects, thereby varying the action of the motors and compressor; and this, in turn, may suddenly and materiall '(even if only temporarily) change t e effective relation of air-supply to the normal requirements of the air-liftsystem. Such variations may frequently be sufficient, in practice, to disarrange the operation of a multi-stage air-lift, unless overcome instantly by counter-acting forces; this is accomplished in the present system by the described capacity thereof for a re verse-to-normal mode of action, and for the automatic resuming of a normal forwardl acting mode of action, and by having tli e described inter-regulative function effective under each of these relatively reverse modes of action.-

In this connection, it should also be pointed out, that the continuity of operation maybe disturbed, or in some instances suspended, as the result of .accidental causes, especially in mines and uarries, and in certaln industrial plants. or instance, the water-supply may be changed in character, or in specific gravity, by the incorporation therein of dust or silt, or it may become impregnated with gas, or gas-forming .materials, in. one (or a few) of the submergence-columns; this latter accident might so reduce the submergence-effect at one or more points, as to prevent the coacting aeration from producing a forward flowage of the liquid in the system. Also,

es eciall in certain wet mines one of the P y a columns may .be suddenly flooded from above, thereby over-charging a submergence column, or an energy-converter, or both, to the extent of halting the operation of the entire apparatus. In these and other ways, either a single air-lift or a series system,

may be stopped; but in the present system,

this has the unusual capacity, as already explained, of normally being self-righting, and self-restarting upon the subsidence or removal of such an interrupting cause, and

of thus resuming operation in a normal and self-continuin manner.

A further eature of improvement in the airlift pair, and in the operation thereof, is

more clearly indicated in Fi 3, this View being analogous (in the main) to Fig. 2.

Assuming the apparatus to be operating regularly, and with the supplemental submergence head maintained at rest,as described in connection with Fig. 4 ,then, it

is evident the upflow stream into secondary uptake pipe B must be just equal in quantity per unit of time, to the flow through port P into the main submergence container, or column D If, now, the rate of 2.5 flowage of said stream into pipe B should be accelerated as a result of a change of action in pipe B ,as may readily and often occur for reasons already stated, this instant increase would naturally have the effect (at least momentarily) of reducing the effective pressure in the entire length of such stream, and would thus instantly decrease the opposition of this stream and its pressure to a more rapid inflow through said port P Thus an increase of flowa e velocity in one pipe instantly and normal y decreases the resistance to the stream flowing thereinto; and this result is deemed to be one of the most important of the interactive functions of any pair of coacting airlifts. The said intermediate uptake-column, B, has a special relation to the next preceding and to the next following air-lifts, (see Fig. 3) in that the up-fiowing stream in B is not only elastic, but is coactive between, and subject to the constant restraint of, two nonaerated liquid down-flowing streams each of which is in communication with said elastic stream at positions therein which are under the pressure of a constant head of forward, direction; and these inertia resistances are coactive with each other through sald elastlc stream being intermediate thereto. At the same time said downflowing stream (in column D), is coactive with and intermediate to the two upflowing elastic streams in columns B and B, so

that in the said coaction of the streain in column D with the elastic stream in column B this stream in column D so acts after being modified in its (otherwise normal) action by its said coaction with the elastic stream in column B Thus the total coaction as regards either said stream, is of a composite nature, and comprises coactive efi'ects appurtenant to several and different pluralities of column streams, which operate concurrently.

Thus it may be said that in the more extended developments of the present invention, there is a multi-lift system of airlift elements connected for uni-flow operation, and comprising successive (two or more) of the column-pairs, through which the liquid stream is not only continuous, but is subjected to the controlling effect,-at each said down-turn portion thereof,of a constantlyacting super-head pressure. These columnpairs, as B and D or B and D (Fig. 2 or Fig. 3), may thus be said each to be topconnected by an economizer-regulator, since the converter, as K, economizes the residual energy of the upflowing aerated stream, and thus, also, is coactive for providing the head required for use in effecting the interactive regulation, and thus effect the auto-governing.

A further and special purpose of said upward extensions of the columns D, is to provide a head of 1i uid which is not located directly in the pat ofthe stream, (see Fig. 4), but is so joined to and above such stream-path that this head of liquid constitutes a suflicient reserve or supply to which liquid may be added from below, (by an under-feed method), and from which liquid may be withdrawn, in and for the interactive regulation of the successive airlift'ele- 'ments, and without materially affecting either the continuity or flowage of the liquid in its said path nor as a unifiow stream, nor the plus-atmospheric pressure under which this flowa e takes place in said down-turn portions t ereof. Thus the stream considered as a whole,and on the occurrence of, variations in the operation thereof,may

have applied instantly thereto, a force and.

a liquid-supply (drawn from one or more of said reserve heads) tending to supplement or to counteract s uch stream-variations and thereby restore a regulated and normal flow.

A further feature of the inter-regulativc functioning, relates to the effects produced on the inflow of air through nozzles N, by the varying momentum's and 'inertias of the down-flow streams in columns D, whereby, at certain momentsand under the varying conditions of the, connected up-flow streamsin columns. B,-the rate. of the air supplied through one nozzle may be changed for the moment and in an automatic manner, and

\ tions occur simultaneously at successive thus become directly co-active in relation to the governing of the operation of the system. In an extended multi-stage system, those air-flowage variations may occur in one portion of the series to increase the airsupply of one uptake-stream, while in another portion of the same series of airlifts, the supply of air through the nozzle of another uptake column may be decreased; or, such increases,or decreases, as the case may be,may occur simultaneously at such different positions in the series.

For instance, when there is an increase of pressure in column D (see Figs. 2 and 3) while the pressure in column D remains stationary (for the moment), the normal effect is to apply more pressure to the lower end of the stream entering column B and thereby somewhat increase the resistance to the in-flow of air through nozzle N And, should the pressure-resistance in column D be suddenly reduced, while no increase of pressure should then occur in column D, a normal result would be to permitg for the moment, an increased flow of air through said nozzle N3, and thereby, also, aid (both. directly and indirectly) in restoring a balanced operation of the whole system. Such changes, occurring at any point in the system, tend instantly on beginning, to modify the pressure or rate of action at adjacent points and thereby counteract the otherwise disturbing effect of such a change from the normalv balance, and thereby aid in securing an interactive regulation as a result of the reciprocal and peculiar coaction elsewhere herein more fully described.

Since, as above pointed out,-a variation from auniformity of functioning at any one of said points of the regulative action, operates by transmissionof the effect (of such Variation) in a forwardly and also in a backward direction,and this at the same instant,-therefore, when two such varia- O- sitions, respectively, in the system, all t at portion of the system which is intermediate to the. said locations of the variations, is subjected to a plurality of the transmitted regulative influences, or effects, with the result that the complete regulation,.-when any is needed at any place or instant',is of a complex natuie, and is accomplished in such a prompt and eflective maimer as to involve only a relatively small change in any oneof the super-head column-increments. And, in such a complex regulative operation, or functioning, when a variation of action occurs in one uptake-column (exceptthe primary one), this action is transmitted, or

reacts, through the directly coasting sub-- mergence column and thus tends to reyerse-f ly modify the super-head or column-increment which serves as the supply-means in the regulation of the pressure-head of this submergence column.

It will now be evident how the describe graduation of the transmitted regulative effects, from a variation-inaction occurring initially at a position above midway in an extended system,-especially When'thenum' her of airlift-members exceeds three or four,has the important feature of gradually reducing the extent of the interaction in passing through such a series, until the total-effect becomes distributed in a manner tending to produce a restoration of a completely balanced action throughout the series, including the airlift-member in which the variation first arose. Another valuable result is that when two (or any plurality of) such variations occur simultaneously, or nearly so, at relatively distant points,- (or originate in non-contiguous airlift-members), the resultant series of transmitted variations may blend together (as transmitted to and appearing at intermediate points) and thus be more quickly neutralized, and become coactive more quickly and fully in effecting the required balancing of the operations of each airlift-member, and of the system as a whole. And this equalization of said variations and transmitted effects is further favored by the described delaying (owing to the time intervals required therefor) of the successive said effects, so that any plurality of such initial variations-ofaction become rapidly restored by the described intcraction, this normally proceeding both forwardly and backwardly in the series of airlift-members, from each of said initial variations.

Owing to the described transmission,- forwardly and backwardly in a system comprising two or more of the airlift-members,of the said initial variations-ohm:- tion, and of the said regulative actions for counteracting the same, it will be evident that each of said airlift-members shares in the operation and functioning of the member or members which are next thereto in the system, so that in the connected series of such members, none.of them can be said to operate alone, or as an independent, or single, airlift. Thus the systemhas the character of a unitary apparatus, and as one arranged for performing and effecting a single operation and result, this being to elevate the. liquid through the entire distancerequired and by a uni-flow stream having therein no points of disconnection, regardless of the number of times,during such total lift,this stream shall be subjected to the forwardly-impelling pressures, or to. the successive aerations and de-aerations whereby said pressures (or submergence-effects) maybe produced and applied thereto. For these purposes, the successive means,as for instance, the conduit formations,for aeration and de-aeration of the liquid should be so placed and proportioned that the aggregate force thus exerted on the stream will correspond in .power to the height the liquid is to be lifted in passing from the intake point up to the point of final stream discharge.

In ordinarypraetice, as is well-known, the kinetic effect of a giVensubmergencehead in pushing up an aerated liquid column in a connected uptake pipe, is directly alfccted by any variation in the resistance to up-flow of said aerated column. This resistance, as also well-known, ordinarily and normally varies in a fluctuating'mam ner, so that the resultant uptake flowagemay be described as normally having a wave-like action, and this result may occur,

or accrue, with a varying degree of 'force,

and with a variable periodicity. One cause of those variations is understood to arise from a fluctuation in the rate of coalescence, and the consequent enlargement of-the size of the air-bubbles in the HP-flOWlXlg aerated column so that any abnormal increase of the coalescence, even momentarily, thereby increases the velocity of the upfiow, or floation rate, ofthe bubbles in and relatively to the upflowing liquid content of the aerated column. g

These wave-like variations may occur, in the present multi-stage system, simultaneously in two or more of the uptake-columns, or' they fimyj occur therein in alternation, 0 that two of said kinetic resistances may occur in two successive uptake-columns at the same-moment and thereby apply to the uni-flow stream a double resistanee-effeet; and, at another moment, an increased resistance may occur in one said column simultaneously with a decreased resistance occurring in another said column. 1 Thus, in the operation of the system as a whole, one said action may for the moment either counterbalance. or supplement the other, so that these actions may be said to become coactive each with the other.

A well-known objection to the use of uptakecolumns of eat length, arises from the lar ratio 0? increase in the volume of a bu ble in passing upward therein, due to the great range of pressure to which such bubble is thus subjected, and since the slippage also increases with the increase of diameter of the bubbles, the loss normally arisin from this cause is in itself a considera le one, "besides causing an increased amount of coalescence. This latter result is often, a' serious one, the frequent but irreggmh r combining of two or more bubbles intoone,"operates .unduly to increase the volume of a bubbleand .hence to furtherincrease, the rate of the slippage, as well as to. accelerate .the velocity} of the upentire length (height) of the uptake column.

By using onl relatively low lifts, and a sufiicient num er, or series, of-these multilift stages for raising the liquid to a given elevation, not only are the pressure changes brought within a smaller range, and the slippage reduced in quantity and velocity, but a relatively greater number of spouting-column energy-conversions are obtained in a given height.

This feature and advantage is deemed to be of special importance, since in such a lower-pressure system the aggregate of surface-contact between the air-content and i the water-content of the upflowing column is much greater in pro ortion to the relative quantity therein 0 free-air, so that a relatively large ratio of heat transference,- within practicable limits,can now be economically obtained, and this in connection with a' minimizing of the well-known initial loss of heat due to the described aircompression and radiation.

Usually the heat developed in the airsupply uy its compression is necessarily lost by radiation before this air can be incorporated (in the form of bubbles) into the lower end of the aerated. up-take column, so that, at this'lower' point (or level), the air and water are of substantially the same temperature. During the movement of the bubbles upwardly from said lower level, the air thereof continuall becomes *cooler by reason of their expansion, andthis loss of heat is gradually and largely compensated by the transference by conduction of heat from the water to the air by means of said surfacercontact of the bubbles with the water.

These combined gains and advantages are also obtained, in the present system, in connection with a further advantage and result which is deemed to'be of special importance as regards. I the inter-regulative

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