US005078975A United States Patent 1191 pi] Patent Number: 5,078,975 Rhodes et al. [45] Date of Patent: Jan. 7, 1992 DROP DEPLOYMENT SYSTEM FOR Primary Examiner-Olik Chaudhuri CRYSTAL GROWTH APPARATUS Assistant Examiner-Felisa Garrett Attorney, Agent, or Firm-Robert L. Broad, Jr.; Jerry L. Inventors: Percy H. Rhodes; Robert S. Snyder; Seemann Marc L. Pusey, all of Huntsville, Ala. 1571 ABSTRACT Assignee: The United States of America as represented by the Administor of the This invention relates to a crystal growth apparatus (10) National Aeronautics and Space generally used for growing protein crystals wherein a A mtion, Wa shington, D.C. vapor diffusion method is used for growing the crystals. Appl. NO.: 629,740 In this apparatus, a precipitating solution and a solution containing dissolved crystalline material are stored in Filed: k.18 ,1990 separate vials (12,14), each having a railient diaphragm Int. Cl.5 ................................................ C30B 7/02 (28) across one end and an opening (24) with a punctur- U.S. Cl. .................................... 422/253; 156/600; able septum (26) thereacross at an opposite end. The 156DIG. 62; 156/DIG. 93 vials are placed in receptacles (30) having a manifold Field of SePrch ....... 156/600, DIG. 62, DIG. 93; (41) with a manifold diaphragm (42) in contact with the 422/102, 245, 253 vial diaphragm at one end of the receptacle and a hol- low needle (36) for puncturing the septum at the other References Cited end of the manifold. The needles of each vial communi- US.P ATENT DOCUMENTS cate with a ball mixer (40)t hat mixes the precipitate and protein solutions and directs the mixed solution to a 3,013,311 12/1961 Meissner ..................... 156/DIG. 62 4,517,048 5/1985 Shlichta .............................. 422/245 drop support (64) disposed in a crystal growth chamber 4,886,646 12/1989 Carter et al. ........................ 156/600 (la), the drop support being a tube with an inner bev- 4,909,933 3/1990 Carter et al. ........................ 210/205 elled surface (66) that provides more support for the 4,917,707 4/1990 Charmonte et al. ................ 156/600 drop (68) than the tubes of the prior art. A sealable 4,919,899 4/1990 Hermann et al. ................... 156/600 storage region (70) intermediate the drop support and mixer provides storage of the drop (68) and the grown OTHER PUBLICATIONS crystals. “Microdialysis Crystallization Chamber”; Sieker; Jour- nal of Crystal Growth 90 (1988); pp. 349-357. 26 Claims, 3 Drawing Sheets U.S. Patent 5,078,975 Jan. 7, 1992 Sheet 1 of 3 P U.S, Patent 5,078,975 Jan. 7, 1992 Sheet 2 of 3 I c- 1 U.S. Patent 5,078,975 Jan. 7, 1992 Sheet 3 of 3 "1 t 5,078,975 1 2 1 fone, a translucent material, the solutions are dificult to DROP DEPLOYMEW SYSTEM FOR CRYSTAL load and evaluate, and the capping procedure cannot be GROWTH APPARATUS evaluated for its sealing and compatibility before flight. Further yet, large crystals may not be eollectible, and ORIGIN OF THE INVENTION 5 marginally collectible crystals may become damaged as The invention described herein was made by an em- they are drawn back into the small openings of the ployee of the U.S. Government and may be manufac- pipettes, or otherwise become “hung” on a surface tured and used by or for the Government for govern- between the two pipettes. mental purposes without the payment of any royalties Accordingly, it is an object of this invention to pro- thereon or therefor. 10 vide an improved crystal growth apparatus that more efficiently mixes precipitate and protein solutions, is FIELD OF THE INVENTION better configured to support a drop of solution, and can This invention relates generally to protein crystal capture and protect crystals of the largest size grown. growth devices, and more particularly to such an appa- SUMMARY OF THE INVENTION ratus for use in a microgravity environment wherein protein and precipitate solutions are stored in separate A crystal growth apparatus is constructed wherein a containers and mixed by a ball mixer upon deployment. vapor diffusion method is used to control crystal growth in a plurality of closed growth chambers each BACKGROUND OF THE INVENTION having a wicking element dampened with a precipitate In the past, microgravity protein crystal growth ex- 20 solution, and a drop support proximate each wicking periments utilizing a well known vapor diffusion element for supporting a drop of fluid in which crystals method for concentrating a drop of protein solution are grown. Additionally, for each growth chamber, a within which protein crystals are grown have typically pair of fluid containers are coupled to a mixer in turn taken place in an apparatus housing a number of crystal coupled to the drop support, for mixing fluids in the growth experiments which are activated simulta- 25 containers, after which the mixed fluids are moved to neously. In one particular embodiment of such appara- form a drop on the drop supporter. After a predeter- tus, crystal growth chambers are each provided with a mined period of time during which crystals are grown, wicking element dampened with a precipitate solution remaining portions of the drops and crystals therein are of a concentration calculated to draw solvent from the drawn into separate storage regions, one for each drop, drop at a selected rate over a predetermined period of 30 and sealed for later study. time, slowly concentrating the protein solution and allowing highly ordered protein crystals to form. The BRIEF DESCRIPTION OF THE DRAWINGS protein droplet is situated at the end of a single pipette FIG. 1 is a view, partially in section, of an embodi- or side-by-side pipettes located near the wicking ele- ment of the present invention. ment, with the pipettes each coupled to a small syringe 35 FIG. 2 is a sectional view taken along lines 2-2 of containing, in the single pipette version, a pre-mixed FIG. 1. solution of precipitate and protein solution. When de- ployed, the pre-mixed solution forms a drop at the end FIG. 3 is a cut-away view of a ball mixer of the pres- ent invention. of the pipette. Each pipette of the side-by-side version is coupled to a separate syringe, one containing the pro- 40 FIG. 4 is a sectional view taken along lines 4-4 of tein solution and the other containing a precipitate solu- FIG. 3. tion, with mixing of the solutions occurring upon de- FIG. 5 is a view, partially in section, of an alternate ployment. This mixing may be achieved by repeatedly embodiment of the present invention. cycling the two fluids into and out of the pipettes and FIG. 6 is a view illustrating particular details of the syringes, or by simply allowing the fluids to mix by 45 alternate embodiment shown in FIG. 5. diffusion after the drop is deployed. The syringes are DESCRIPTION OF THE PREFERRED filled prior to flight, and the pipettes capped to prevent EMBODIMENT fluid loss by plugs connected to a common operating mechanism. When the operating mechanism is oper- Referring to FIG. 1, a system 10 is shown for storing ated, all pipettes are uncapped simultaneously. Like- 50 a precipitate solution and a protein solution in separate wise, plungers of the syringes are also coupled to a vials 12 and 14, and for deploying these solutions in a common operating mechanism so that when operated, crystal growth cavity 16 having a wicking element 18 the drops are deployed simultaneously. moistened with a precipitate solution. While this type device has been proven to work rela- Vials 12 and 14, one for precipitate solution and one tively well during several Space Shuttle flights, prob- 55 for protein solution, are each constructed as shown in lems have occurred. Most notable among these prob- FIG. 1 having a hollow interior 20 for storage of one of lems is the diffrculty of achieving complete mixing, the solutions, and a generally rounded end 22 provided especially when dissimilar fluids are mixed. Another with an opening 24 centrally located therein. A thin problem is that the mechanism that deploys the drops is septum 26 is mounted in opening 24, and sealably con- not designed for repeated cycling, and possibly may fail. 60 tains the solutions in vials 12 and 14 prior to deploy- Additionally, in some instances, the drops were lost due ment. Sealing an opposite end 26 of each of vials 12 and to the relative instabilities between the drops and pi- 14, and in contact with the solution therein, is a thin, pettes during maneuvers in space. Further, cycling of flexible diaphragm 28. The vials are slidably disposed in the fluids as described introduces air bubbles therein, receptacles 30 each configured at an interior end 32 to and the mechanical action introduces small but unac- 65 match the rounded ends 22 of vials 12 and 14, with each ceptable temperature rises in the crystal growth enclo- interior end 32 provided with a hollow needle 36 sure, which is temperature-regulated to f0 .1 degree C. aligned with opening 24 of vials and 14. At an opposite Still further, as the syringes are constructed of polysul- end 38 of receptacles 30 is a hollow enclosure or mani- 5,078,975 4 fold 41 provided with a flexible diaphragm 42 generally FIG. 1, with the wicks 18 also being resilient, the wicks in contact with the respective vial 12 and 14 and its positioned in a rectangular region between springs 80. diaphragm 28. A source of hydraulic or pneumatic Wicks 18 are each provided with a depression or cavity pressure 43 is in turn connected to each of manifolds 41 82 adjacent drop support ends 64, depressions 82 form- via conduit 45 such that when pressure is provided to 5 ing the crystal growth chamber 16. manifolds 41, manifold diaphragm 42 applies pressure to In operation, and refemng to the embodiment of the respective vial and its diaphragm 28, moving vials FIG. 1, the vials are separately loaded with precipitate 12 and 14 in receptacles 30 and transferring pressure to and protein solutions and placed in their respective interiors 20 of vials 12 and 14 to force the solutions receptacles 30. After being situated in a microgravity upwardly into mixers 40. Needles 36 are each connected 10 environment, drops 68 are deployed by applying pres- via tubes 37 and 38 to a conventional ball mixer 40, such sure to manifolds 41, distending diaphragms 42 and as the ball mixer disclosed in Biophysical JournaZ, Vol. forcing vials 12 and 14 to “bottom out” in the contoured 24, published on 1988, pages 2-20. ends 32 of receptacles 30. When this occurs, needles 36 In this type mixer, as shown in FIGS. 3 and 4, the first puncture septums 26, releasing the contents of each of of the fluids to be mixed is directed through an axial, 15 vials 12 and 14 to be mixed by mixers 40. Continued hollow inlet opening 42 to an asymetrically-shaped ball application of pressure causes manifold diaphragm 42 to 44 spaced from sides 46 of a mixer housing 48, and bear upon and distend vial diaphragm 28, forcing fluids supported by means not shown. Ball 44 is configured in the vials to be forced through mixers 40 and exit tubes having a plurality of opposed jets 50 positioned as 54 to drop support 64 where the drops are formed. At shown and through which a portion of the first fluid is 20 the end of a selected period of time wherein crystals are directed. The remaining portion of the first fluid flows grown, the drops are recovered by removing all or between ball 44 and sides 40 adiacent ball 44. The sec- some of the Dressure in manifolds 41 and allowing dia- ond fluid is introduced into mixer 40 by a plurality of phragms 42 io relax. This draws the drops and crystals ports 52 positioned approximately 45 degrees with re- into storage regions 70 of tubes 54, after which wedges spect to jets 50, and slightly upstream ball 44. As the 25 60 are operated on flat side 61 by cams 62 to crimp two fluids flow through mixer 40,t he reduced-in-diam- sheaths 58 and permanently close tubes 54 at narrowed eter flow path therethrough provides a venturi effect, portion 56. The slide valve 74 is then operated to close increasing velocity of the fluid flow and creating turbu- storage regions 70 at drop supports 64. To recover the lence that thoroughly mixes the fluids they as they flow crystals, the wicks and sponge springs are removed, around ball 44, the fluids exiting mixer 40 through exit 30 exposing the slide valve, which is also removed, after tube 54. which the storage regions 70 are removed with a special Tube 54, constructed as shown in FIG. 1, is provided extraction tool (not shown) that cuts narrowed portion with a narrowed portion 56 constructed of a flexible 56 at the mixer side of crimped sheath 58. At this point, silicone polymer material with a sheath 58 of thin stain- the fluid and crystals may be removed or the storage less steel or like crimpable material encircling portion 35 portions 70 of tubes 54 may be capped and stored for 56. A cam driven wedge 60 is movably positioned adja- later study. cent portion 56, with wedge 60 positioned to crimp An alternate embodiment of this invention is shown sheath 58 when driven on a flat side 61 by cam 62, in FIG. 5. Here, a TEFLONTM (or other inert mate- effecting a closure of tube 54 at narrowed portion 56. rial) shaft 84 is closely fitted in and rotatably mounted in From narrowed portion 56, tube 54 continues to a drop 40 a cylindrical channel 92 cut, machined, or molded in a support end 64 terminating in crystal growth chamber rigid block of material 94, this material selected to be 16, drop support end 64 having a beveled inner region compatible and non-reactive with fluids used therein. 66 which is better adapted to support a drop of fluid 68 Shaft 84 is provided with transverse fluid deployment than a flat-tipped pipette generally used in the prior art. passageway’s 86 and separate transverse storage and The internal dimensions of this drop support end por- 45 recovery passageways 88 each having a free piston 118 tion 64 is constructed to form a storage region 70 for (FIG. 6), passageways 88 positioned normal to and grown crystals, such storage region extending between offset from passageways 86. A plurality of crystal narrowed portion 56 and drop support end 64 and hav- growth chambers 90, each having a drop support open- ing a diameter and length to accommodate the largest ing 106 as described above, are positioned in block 94 crystals grown in drop 68. Additionally, beveled inner 50 on one side of shaft 84, with a like plurality of fluid region 66 provides a funneling effect to channel crystals dispensing apparatus 102 positioned in block 94 on an into storage region 70, reducing the probability that opposite side of shaft 84. Fluid dispensing apparatus are crystals may become “hung” at the end of drop support each constructed as shown in FIG. 5, with a free piston 64. 112 disposed to move the fluid in containment regions Drop support ends 64 may be set flush in a rigid 55 108 through mixers 104 responsive to pressure from support 72 (FIGS. 1 and 2), or as shown, ends 64 may bore 101. Storage and recovery passageways 88 are of a protrude slightly above support 72. A slidable and lift- larger bore than deployment passageways 86, also as able valve member 74 positioned over support 72 is described above, to capture and store crystals of the operated by a cam member 76, with valve member 74 largest size grown. A thumbwheel 96 connected to one having openings 78 disposed to be selectively posi- 60 end 98 of shaft 84 allows shaft 84 to be rotated, either tioned in registry with support ends 64. Cam member 76 manually or by electronic means (not shown), and the is provided with a frictional surface 77 which bears on opposite end of shaft 84 is threaded and rotatably sup- an underside of valve member 74, allowing it to simulta- ported in a threaded portion 100 of channel 92 to rotate neously lift and slide valve member 74 to cover drop and move shaft 84 longitudinally, selectively aligning support ends 64 or bring openings 78 into registry with 65 growth chambers 90 with fluid deployment passage- drop support ends 64. Valve member 74 is biased ways 86 or recovery and storage passageways 88. Addi- against support 72 by a plurality of resilient sponge tionally, pressure passageway 101 for communicating rubber springs 80, which are configured as shown in pressure to dispensing apparatus 102, when deployment 5,078,975 5 6 passageways 86 are aligned with dispensing apparatus 1. A crystal growth apparatus including a housing 102 and drop supports 106, is coupled to a source of having a plurality of crystal growth chambers therein, pressure or suction 111 via bore 109 (solid lines) in shaft said apparatus comprising: 84, while suction passageway 105 for communicating at least a pair of fluid containers, the first container of suction to recovery and storage passageways 88 is 5 said pair of containers containing a solution of couplable to source 111 via a bore 107, shown in its dissolved material for growing crystals and the actual position (solid lines) and its operative position second container of saib pair of containers contain- (dashed lines). Source 111 of pressure or suction, for ing a precipitate solution for facilitating crystal example, may be a manually operated syringe, for pneu- growth; matically generating the pressure or suction, or an auto- 10 miXing means in communication with said containers mated, regulated source of pressure or suction. The ball for receiving and miXing said solutions and for mixers 104 are mounted proximate dispensers 102, but directing said mixed solutions into said growth may be mounted in shaft 84 (not shown). chamber; In this embodiment, the solutions to be mixed are a kcking element in each said growth chamber and contained in cylindrical or tubular containment regions Is disposed for containing a predetermined quantity 108. Regions 108 are coupled at one end 110 via con- of precipitating agent; and duits 113 and 115 with ball mixers 104, and as stated, are Closure means for d i n g said growth Chamber re- provided with free pistons 112 at the opposite end 114. sponsive to admission of said mixed solutions A single opening 116 in end 114 of regions 108 is con- 2o therein. nectible to source of pressure 111, which provides en- 2. An apparatus as set forth in Claim 1 including a ergy to move pistons 112 in order to deploy the fluids storage Chamber in c~~municatiownit h said growth through mixer 104 to form the drop at drop support chamber, for dablY storing grown Crystals therein. openings 106. 3. An apparatus as set forth in claim 2 including drop For recovering the remainder of the drop and 25 Support means positioned near said wicking means, for tals therein, the recovery and storage passageways 88 in supporting a drop of fluid in said growth chamber. shaft 84 are also provided with free pistons 118 (FIG. 4- An as set forth in including 6). H ~as o~ne e~nd 1,20 of the storage passageways 88 means for forcing and directing said solutions into said are aligned with the source of suction 111, the opposite mixing ends of passageways 88 are also aligned with drop SUP- 30 5- An apparatus as set forth in Claim 4 including clo- port openings 106. This allows the remaining portion of sure means for sealing said growth chamber responsive the drop and crystals therein to be drawn into storage to ‘* admission therein of said mixed solutions. passageways 88 responsive to suction applied to piston An apparatus as set forth in a storage chamber disposed in communication with said 118. For the embodiment shown in FIG. 4, operation is as 35 growth chamber. follows. The fluids are loaded into channels 108 with 7. An apparatus as set forth in wherein said closure means is disposed for sealing said storage means. pistons 112 behind the fluid, and shaft 84 to a 8. An apparatus a set forth wherein said position to seal dispensing apparatus 102, this position - drop support means is positioned intermediate said being other than a position of alignment of either de- 40 growth chamber and said storage chamber. ployment passageways 86 or recovery and storage pas- 9. A crystal growth apparatus having a plurality of =geways 88 with apparatus lo2a nd drop closable crystal growth chambers in a vapor Openings ‘06’ Upon deploment, shaft is diffusion method for growing crystals in a drop of fluid rotated, bringing deployment passageways 86 into reg- is used, sai& apparatus comprising: with apparatus lo2a t One end and a wiCbg element in each said growth chamber dis- drop support openings 106 at the other end. This action 45 posed for containing a predetermined quantity of also aligns source 111 of pressure via passageways 101, precipitating agent; 109, and 103 with dispensing apparatus 102, which pres- drop support proximate said wicking element sure being sufficient to move pistons 112 in channels 108 in each said growth chamber, for supporting a drop to discharge the fluids through mixers 104 to form the 5o offluid containing a dissolved from which drops at drop support openings 106 in crystal growth crystals are grown; chambers 90. For recovering the remainder of the drops at least fluid containers for.each said drop sup- and the grown crystals after the requisite time period port means, one containing a solution of said dis- has elapsed, shaft 84 is again rotated, bringing storage solved material and the other containing a precipi- redons 88 in shaft 84 into registry with growth cham- 55 tate solution for facilitating crystal growth, said bers 90 at one end and with suction passageways 103, containers each further comprising opposed ends 107, and 105 at the opposite end. This suction is suffi- having an opening at one of said ends; cient to draw piston 118 back in passageways 88, which means for selectively applying pressure and suction in turn draws the remainder of the drops into storage to interiors of said containers at an opposite end, redons 88. The shaft is then rotated to the intermediate 60 for moving said solutions through openings; position, d i n g storage regions 88. TO remove the a discrete mixer for each said drop support means and crystals, the shaft is removed and the crystals flushed respective said fluid storage containers, said mixer from the respective storage regions and stored in sepa- having inlets coupled to said openings of said fluid rate vials, or capped and stored for later study. storage containers and an outlet through which Having thus described our invention and the manner 65 said solutions are passed responsive to said pressure of its use, it is apparent that incidental modifications applied to said interiors, for mixing said precipitate may be made thereto that fairly fall within the scope of solution and said solution of dissolved material as the following appended claims, wherein we claim: said solutions pass therethrough; and . 5,078,975 7 8 a fluid and crystal storage region coupled to each said 18. A crystal growth apparatus for growing crystals drop support means and being sealable downstream in a plurality of separate drops of fluid, each drop en- said mixer and at said drop support means, for closed in a separate, closable crystal growth chamber sealably storing a recovered portion of said drop comprising: and grown crystals therein. 5 a wicking element in each said growth chambe-r 10. A crystal growth apparatus as set forth in claim 9 dampened with a liquid precipitating agent; wherein said drop support means comprises an opening a drop support including an opening proximate said having a beveled inner edge. wicking element, said opening provided with bev- 11. A crystal growth apparatus as set forth in claim 9 eled interior edges; wherein each said fluid storage containers comprises a 10 a pair of containers for each said drop support, one movable vial having a puncturable septum sealably containing a protein solution and the other contain- disposed across said opening, said vial positioned in an ing a precipitate solution, said containers each hav- elongated receptacle, said receptacle provided at one ing an opening at one end; end with a hollow needle coupled to said mixer and means for selectively applying pressure and suction aligned with said opening, and said opposite end of said to interiors of said containers at an opposite end of vial provided with a first resilient diaphragm for trans- said containers, for moving said solutions through mitting pressure to said solutions, and suction to said said openings; solutions as said pressure is removed and said first dia- a ball mixer disposed for mixing dissimilar fluids and phragm relaxes. having fluid entrance openings and a fluid exit 12. A crystal growth apparatus as set forth in claim 11 2o opening, said fluid entrance openings coupled to wherein said means for applying pressure and suction to said openings of said pair of containers and said said diaphragm of said vial comprises a manifold having fluid exit opening coupled to said drop support; and a seconii resilient diaphragm in contact with said first a fluid and crystal storage region coupled to each said diaphragm of said vial, and a source of pressure selec- drop support and being sealable downstream said 25 tively coupled to said manifold. mixer and at said drop support, for sealably storing 13. A crystal growth apparatus as set forth in claim 9 a recovered portion of said drop and grown crys- wherein said mixer comprises a ball mixer. tals therein. 14. A crystal growth apparatus as set forth in claim 9 19. A crystal growth apparatus as set forth in claim 18 wherein said storage region comprises: 3o wherein said means for selectively applying pressure a tube for containing the drop of fluid and largest and suction to said interiors comprises pneumatic pres- crystals grown therein and coupled to said drop sure. support means; 20. A crystal growth apparatus as set forth in claim 18 a narrowed, flexible region in said tube, said nar- wherein each said fluid storage containers comprises a rowed region having a crimpable sheath disposed 35 movable vial having a puncturable septum sealably therearound; disposed across said opening, said vial positioned in an crimping means disposed for crimping said sheath, elongated receptacle, said receptacle provided at one closing said narrowed region and one end of said end with a hollow needle coupled to said mixer and tube; and aligned with said opening in said vial, and said opposite valve means at said beveled opening, for closing an end of said vial provided with a first diaphragm for opposite end of said tube, sealing said drop and said transmitting said pressure to said interiors, and suction crystals therein. to said interiors as said pressure is removed and said first 15. A crystal growth apparatus as set forth in claim 10 diaphragm relaxes. comprising a shaft having said storage region therein 21. A crystal growth apparatus as set forth in claim 20 and a transverse passageway for each said growth 45 wherein said means for selectively applying pressure chamber, said shaft rotatably disposed and closely fitted and suction to said interiors of said vials each comprises in a cylindrical opening, with said crystal growth cham- a manifold having a second diaphragm in contact with bers each having said drop support means disposed said first diaphragm, and a source of pressure coupled to adjacent said shaft, and said mixer exit opening for each said manifold. said growth chamber communicating with said open- 50 22. A crystal growth apparatus as set forth in claim 21 ing, whereby as said shaft is rotated, each said mixer exit wherein said storage region comprises: opening and each said drop support means are brought a tube for containing the drop of fluid and largest into communicating relation with opposite ends of said crystals grown therein, said tube coupled to said passageway, allowing fluid from said mixer to form said drop support and said mixer; drop, and after a selected period of time has elapsed, 55 a narrowed, flexible region in said tube adjacent further rotation of said shaft aligns said storage region mixer, said narrowed region having a crimpable with said drop support means, allowing said drop and sheath disposed therearound; crystals therein to be stored in said storage region. crimping means disposed for crimping said sheath, 16. A crystal growth apparatus as set forth in claim 15 closing said narrowed region at one end of said wherein each said fluid storage containers comprises a 60 tube; and cylindrical fluid storage region having an opening at valve means at said drop support, for closing an op- one end and a free piston closely fitting said cylindrical posite end of said tube, sealing said drop and said fluid storage region at an opposite end, said piston mov- crystals therein. able therein responsive to pressure and suction applied 23. A crystal growth apparatus as set forth in claim 18 to said piston. 65 wherein said pair of containers each comprises: 17. A crystal growth apparatus as set forth in claim 16 a first cylindrical container having a first opening at comprising passageways in said shaft for selectively one end coupled to one of said fluid entrance open- coupling pressure and suction to said fluid containers. ings of said ball mixer, and an opposite end,having 5,078,975 9 10 a second opening selectively coupled to a source of said drop and said crystals therein to be recovered pressure; and and stored in said storage region. a first free piston closely fitting said first cylindrical 25. A crystal growth apparatus as set forth in claim 24 container and disposed for moving said solution comprising passageways in said shaft for coupling pres- through said first opening responsive to said pres- 5 sure to said pair of containers. sure. 26. A crystal growth apparatus as set forth in claim 25 24. A crystal growth apparatus as set forth in claim 23 wherein said fluid storage region comprises a second comprising: cylindrical container transversely located in said shaft, a shaft having said storage region therein and a trans- said second cylindrical container having an opening at verse passageway for each said growth chamber, 10 one end disposed for communicating relation with said said shaft rotatably disposed and closely fitted in a drop support, and an opening at an opposite end dis- cylindrical opening, with said growth chambers posed for communicating relation with said source of each having said drop support positioned adjacent suction, and a second free piston closely fitting in said said shaft, and said ball mixer fluid exit opening second container, whereby as said shaft is rotated to communicating with said cylindrical opening, 15 align said fluid storage region with said drop support whereby as said shaft is rotated, each said mixer and said source of suction, said suction draws said pis- exit opening and each said drop support is brought ton and said remaining portion of said drop into said into communicating relation with opposite ends of fluid storage region, with further rotation of said shaft said transverse passageways, allowing fluid from misaligning said fluid storage region from said drop said mixer to form said drop at said drop support, 20 support and said source of suction, storing said remain- and after a selected period of time, said shaft is ing portion of said drop and crystals therein in said fluid rotated aligning each said storage region with each storage region. * * * * * said drop support, allowing a remaining portion of 25 30 35 40 45 50 55 60 65