US2730238A

US2730238A - Products

Info

Publication number: US2730238A
Authority: US
Publication date: 1956-01-10
Anticipated expiration: 1973-01-10

Description

Jan. 10, 1956 w. J. SMITH MULTIPLE COMPARTMENT J IGGING APPARATUS Filed July 31, 1952 2 Sheets-Sheet l Jan. 10, 1956 w. J. SMITH 2,730,233

MULTIPLE: CQMPARTMENT JIGGING APPARATUS Filed July 31, 1952 2 Sheets-Sheet 2 RAW COAL Ellyn? FIRSTJIG CELL SCREEN a. HUTCH CoAL MIDDLING5 ea PPoDucTs SOME FINE REFUSE ELEVATOR SECOND JIG CELL REFUSE FINE HuTCH MIDDLINGS CLEAN COAL PRODUCT (FRGM 5CREEN) (FINAL PRODUCT) CHECK VALVE ELEVATOR CRUSHER RAW'COAL FIRs-TJIG CELL SCREEN sIHuTCN COAL MIDDLINGS a. PRODUCTS SOME FINE REFusE ELEVATOR sECoND JIG CELL REFUSE FINE HUTCH MIDDLINGS CLEAN CoAL PRODUCT (FROM SCREEN) (FINAL PRODUCT) ELEVATOR CHECK vALvE CHECK vALvE CRusIIER INVENTOR,

F 3 WILLIAM JSMITI-I,

I 0 BY I States Patent 2,730,238 Patented Jan. 10, 1956 'l ce MULTIPLE COMPARTMENT JIGGING APPARATUS William J. Smith, Worthington,

Ohio, assiguor ta The Jeffrey Manufacturing Company,

This invention relates to jigs adapted to separate material according to specific gravity and one of the main objects of the invention is to provide an improved jig that may be employed with advantage in a high gravity separating medium system such as described by Byron M. Bird in his Patent No. 2,487,845 dated November 15, 1949, for a Jigging Apparatus and Method, to which reference is made for a complete understanding of the operation of a jigging system and method employing a high specific gravity separating medium.

It is another object of the invention to provide improved jigging apparatus including one or more hutch compartments and associated elevator compartments between which they are one-way check valve means for controlling the flow of fluid and solids between the hutch compartments and the associated elevator compartments during cyclic up and down movement of jigging fluid in the jig.

Another object of the invention is to provide an improved jigging apparatus including a hutch compartment and a pair of associated elevator compartments, there being a one-way check valve means between the hutch compartment and each of said elevator compartments to control the flow of the fluid between the hutch compartment and the elevator compartments during up and down cyclic movement of jigging fluid in the jig and for controlling the amount of solids discharged from said hutch compartment into said elevator compartments.

Another object of the invention is to provide an improved jigging apparatus including a material treating compartment and a successive material treating compartment adapted to treat material being separated after it has been treated in the first compartment, there being an elevator compartment associated with both of said compartments and one-way check valves between said compartments to control the flow of fluid and solids between the hutch compartments and the elevator compartment during up and down cyclic movement of jigging fiuid in the jig.

Another object of the invention is to provide an improved separating apparatus adapted for use with a high gravity separating medium wherein material is separated according to specific gravity, the apparatus including a material treating compartment and a successive material treating compartment adapted to treat material after it has been treated in the first compartment wherein the hutch products of both of said treating compartments are removed from the apparatus, preferably but not necessarily, through an elevator compartment common to said treating compartments through one-way check valves that control the flow of jigging fluid and solids between said hutch compartments and said elevator compartment during up and down cyclic movement of jigging fluid in the apparatus and in which the intermediate or high gravity products of the first compartment are removed therefrom, preferably but not necessarily, through said elevator compartment, and the intermediate or high gravity screen products of said successive compartment may be removed therefrom over a different path, crushed and returned to the separating apparatus.

In carrying out the foregoing object it is a further object of the invention to provide an adjustable one-way valve through which the hutch product of the successive compartment may be fed to another compartment and mixed with the intermediate or high gravity screen product of the successive separating compartment in order that the resulting mixture may be returned to the separating apparatus for controlling the specific gravity of the separating medium.

Other objects of the invention will appear hereinafter the novel features and combinations being set forth in the appended claims.

In the accompanying drawings:

Fig. 1 is a view, partly in section and partly in elevation, of a jigging apparatus embodying the invention;

Fig. 2 is a flow diagram indicating one system in which the jigging apparatus seen in Fig. 1 forms a part; and

Fig. 3 is another flow diagram indicating another system in which the jigging apparatus seen in Fig. 1 forms apart.

In Fig. 1 of the drawings there is shown a two stage jigging apparatus including a first jig cell 10 and a second jig cell 11. Each of the jig cells 10 and 11, is in effect, a U-shaped compartment one leg of which is closed and into the top of which air under pressure is admitted and released cyclically through valves to cause water in the cell to rise and fall in the other or working leg of the compartment.

In the working leg of the first cell 10 there is a screen plate 12 above which stratification of material being treated occurs and below this screen plate 12 there is a hutch compartment 13. Material to be treated in the jigging apparatus enters the first cell 10 over a feed lip 14 and during Stratification of it above screen plate 12 much of the fine high gravity material contained therein passes through the screen plate 12 and falls to the bottom of the hutch compartment 13. The stratum of material which is of the lowest specific gravity passes from the first cell 10 over a weir including a plate 15 that is vertically adjustable to determine the total thickness of the bed of materials being treated above the screen plate 12, and all other material is removed from above the screen plate 12, after passing beneath a vertical plate 18, by a star wheel discharge or ejector device 16 in a chute 17.

The star wheel device 16 and the chute 17 are contained within an elevator compartment 19' formed by the housing or casing of a first discharge elevator 19 that enters the jigging apparatus at an angle and

opposite walls

20 and 21 of which form adjacent end walls of the adjacent cells 10 and 11. Material discharged through the star wheel device 16 falls to the bottom of the elevator compartment 19' and is conveyed upwardly and discharged therefrom by an endless chain and bucket conveyer indicated at 22. Extending generally horizontally between the

opposite walls

20 and 21 of the elevator casing or housing and below the top of plate 15 there is a plate 23, which forms the bottom of a feed chute that conveys material spilled over the weir plate 15 into the second jig cell 11.

The construction of the second jig cell 11 is similar to that of the first jig cell 10, described in part above, and it includes a screen plate 24 above a hutch compartment 25, a weir including a vertically adjustable plate 26, a star wheel discharge or ejector device 27 in a chute 28 and a vertically adjustable plate 29 for varying the size of the opening leading to the star wheel device 27. The star wheel device 27 and chute 28 are contained within an elevator compartment 30 formed by the housing of a second discharge elevator 30 which includes

opposite side walls

31 and 32 and an endless chain and bucket conveyor indicated at 33. Wall 31 of elevator 30 forms an end wall of the second cell 11. The wall. 32 forms in part one of the end Walls of the ji ging apparatus. Elevator 30, like elevator 19, enters the jigging apparatus at an angle and a. plate 34 located below the top edge of the weir plate 26 spans the

walls

31 and 32 and forms the bottom of a discharge chute through which material having the lowest specific gravity is discharged from the second cell 11 and the jigging apparatus.

Stratification of material occurs in the second jig cell 11 just as it does in the first jig cell 10, namely, fine high gravity material passes through the screen plate 24 and falls to the bottom of the hutch compartment 25, the material having the lowest specific gravity spills over the weir plate 26 and all other material of intermediate specific gravity, known in the art as middlings, is discharged into the second elevator compartment 39 through the chute 28 and the star wheel discharge device 27.

Many of the details of the jigging apparatus shown in the drawings are not here described because the construction and mechanical operation of the jig here employed to illustrate the present invention is identical to the jig shown and described by Orval R. Strawn in his Patent No. 2,281,530, dated April 28, 1942, for a jig, with the exception of certain valves hereinafter described, which eliminate the necessity of certain ejector parts of the Strawn jig. Reference is made to this patent for a complete understanding of the jig per se and its operation.

The wall 26 of the elevator 19 is cut away adjacent the bottom of the hutch compartment 13 to provide an opening 35 through which hutch material may flow from the hutch compartment 13 into the elevator compartment 19 formed by the casing of elevator 19. Walls 21. and 31 are cut away adjacent the bottom of the hutch compartment to provide

openings

36 and 37 in the

walls

21 and 31 respectively, through which hutch material may flow from the hutch compartment 25 into both of the compartments 19 and formed by the housing or casings of

elevators

19 and 30.

It has been found in practice that where there is an uncontrolled opening or openings, such as any or all of the

openings

35, 36 and 37, between a hutch compartment and an elevator compartment that there is a back flow of separating liquid from the elevator compartment into the hutch compartment during the suction stroke in the hutch compartment.

The return or fall of the separating fluid on the down or suction stroke of a normal jigging cycle in which mixed sizes of material are being treated should be as rapid as possible in an air operated jig. Consequently any back flow of separating liquid from an elevator compartment into a hutch compartment through an opening such as any of the

openings

35, 36 or 37 tends to retard the rate of fall of separating fluid during the suction stroke and is highly undesirable.

For the purpose of preventing back flow of liquid from the

elevator compartments

19 and 30 into the

adjacent hutch compartments

13 and 25, I have provided three one-way

check valve devices

38, 39, and 40 associated with the

openings

35, 36 and 37 respectively. These one-way

check valve structures

38, 39, and 40 will permit the flow of fine high gravity hutch material and separating liquid to pass from the hutch compartments into the elevator compartments during the pulsion strokes in the cells of the jig, but they restrict or prevent substantially any back flow thereof from the elevator compartments into the hutch compartments during the suction strokes in the cells of the jig.

It has also been found in practice that there is a circulation of material being stratified along any wall of a jigging compartment and that this circulation occurs in a vertical plane so that the particles move downward close to the wall and upward further out in the bed in a sort of circular motion. For instance, those particles within approximately 1 inch from the wall move downward, then turn and move upward at a distance of approximately 3 or 4 inches from the wall. Obviously, this is highly undesirable in that it in part destroys the Stratification that has occurred in the jigging cycle.

The explanation of this phenomenon is probably this: A vertical wall any place in a jig bed, either along the side or out in the middle of the bed, provides a path of low resistance for the downward currents of water. For that reason, the water travels next to the wall more rapidly than in the major portion of the bed where it must follow a tortuous path through the interstitial openings between the particles comprising that bed. As a result of the rapid motion of the downward currents next to the wall, the particles are jammed tightly at that point. Thus, when the next upward pulsation stroke occurs those particles next to the wall are last to move, there being less resistance in the balance of the bed. In this way they lag behind on every upward or pulsion stroke and move more rapidly on the downward or suction strokes. This apparently causes the circular motion that has been observed.

Obviously, if the strong downward currents can be reduced next to the walls formed by the

plates

15 and 18, and 26 and 29 on the downward stroke, this objectionable circulation of material along these walls will be eliminated. Experience shows that a very small quantity of water added adjacent to such a wall prevents this undesirable packing of the particles against that wall. If a low head of water, of a few inches, is maintained in the elevator compartments 19 and 30' water flows backward from the elevator compartments 19' and 30 during the suction strokes in the jig cells 10 and 11 through the start gates and reduces the downward velocity of the water along the walls formed by

plates

15 and 18, and 26 and 29. The

hutch valves

38, 39 and 40 serve to maintain this low head of water in the

elevator compartments

19 and 30.

Check valve device 38 includes a box type structure 41 which cooperates with the wall 20 and a downwardly sloping bottom portion of the hutch compartment 13 which is adjacent the opening 35 so as to prevent any flow of liquid from the compartment 13 to and through the opening 35 except through an opening 42 which is provided in said box 41. Said opening 42 is formed by the bottom of a cross channel 43, which forms a part of box 41 and the bottom of the hutch compartment 13 directly therebelow.

A flexible valve element 44, preferably made of rubber material, such as ordinary rubber belting, is provided, the top of which is rigidly attached as by a bolted cross plate 45. The bottom portion of the flexible element 44 is normally curved so as to have a wiping contact with the adjacent bottom portion of the compartment 13. The sides of the valve element 44 overlap upstanding side portions, not shown, of said box 41. Reinforcing ribs 46 extend laterally downwardly from the channel 43 to which they are rigidly attached, as by welding, and terminate just above the adjacent bottom wall of the hutch compartment 13.

The construction, operation and function of valve 38 may be identical to that of any of the valves shown and described in my Patent No. 2,573,503, dated October 30, 1951, for a Hutch Valve for Baum Jigs, and from the foregoing description of this valve it will be apparent that whenever the fluid pressure in the hutch compartment 13 is greater than the fluid pressure in the elevator compartment 19' that the valve element 44 will swing to allow fluid andv fine high gravity material to flow from the hutch compartment 13 into the elevator compartment 19'. This condition will normally occur during the pulsion stroke, or as the separating liquid moves upwardly through the screen 12 and the bed of materials supported thereby. During the suction stroke the fluid pressure in the hutch compartment 13 will be less than the fluid pressure in the elevator compartment 19 and therefore valve element 44 will be swung to prevent the reverse flow of fluid from the elevator compartment 19 to the hutch compartment 13.

The one-

way check valves

39 and 40 include structure which is identical to that above described in connection with valve 38 and these valves are positioned Within the hutch compartment so that their

boXes

47 and 48 respectively, which correspond with box 41 of valve 38, cooperate with the

walls

21 and 31 respectively. These

valves

39 and 40 differ from valve 38 only in that they each include a vertically adjustable control gate 49 that is carried in upright tracks 50 disposed one at each side of each gate 49. Each gate 49 is adjusted vertically by a rack 51 and a pinion 52 carried on a horizontally disposed shaft that projects through one side of the lig through a suitable shaft seal, not shown.

The gate 49 of each

valve

39 and 40 may be adjusted to any of various positions from a full closed position wherein it prevents any flow of fine high gravity material from the hutch compartment 25 to a full open position wherein it in no way effects or controls the flow of fine high gravity material from the hutch compartment 25 into the elevator compartments 19 or The above described arrangement of valves and their operation constitute important features of the present invention and their other functions may be best illustrated by reference to Figs. 2 and 3 of the drawings which are flow charts illustrating jigging systems including a jig built as above described. The flow charts of Figs. 2 and 3 use coal as an example of material undergoing separation, but it is to be understood that the jig and systems here described may be employed for treating other materials, such for example as iron ore wherein the high specific gravity materials constitute the values.

The jigging system described by the flow chart of Fig. 2 of the drawings is a system wherein stratification of materials in the jig is accomplished in a high gravity separating medium such as is disclosed by Byron M. Bird in his Patent No. 2,487,845 above mentioned. In my system the separating medium, which includes water and solids, is built up from crushed and unscreened middlings removed from the screen plate 24 of the second jig cell 11 through the star wheel discharge device 27.

When the jig shown in Fig. 1 is employed in the system illustrated in Fig. 2 of the drawings, the gate 49 of hutch valve is adjusted to prevent any flow of high gravity fine material to the elevator compartment 30' and the gate 49 of valve 39 is adjusted so as to permit fine hutch material to flow from the hutch compartment 25 into the elevator compartment 19'. Valve 38 always permits fine high gravity material to flow from hutch compartment 13 into the elevator compartment 19.

Because the valve 40 functions only to close the opening 37 in this system it is not shown in the flow chart of Fig. 2, and in fact, in this particular system the valve 46 could be omitted from the jig if the opening 37 were otherwise closed or omitted.

' In this system raw coal is fed over the feed lip 14 and into the first jig cell 10 where, during Stratification of the bed of materials above the screen plate 12, much of the fine high gravity material passes through the screen plate 12 and sinks to the bottom of the hutch compartment 13. This fine high gravity material then flows through the check valve 38 and into the elevator compartment 19. The stratum of material which is of the lowest specific gravity flows over the weir plate 15 and into the second jig cell 11. This material will contain substantially all of the coal, some middlings and some fine high gravity material. Those screen products which do not pass through the screen plate 12 or flow over the weir plate 15 are removed from the screen plate 12 by being fed into the elevator compartment 19 through the star wheel device 16 from which they and the fine high gravity material from hutch compartment 13 are sent, for example, to a refuse pile by the chain and bucket elevator 22.

Material which is fed into the second cell 11 from the first cell 10 by passing over the weir plate 15 undergoes stratification in the second jig cell 11 in the presence of the high specific gravity separating medium that includes water and recirculated, crushed but unscreened middling products removed from above the screen plate 24 in the second jig cell 11.

It is pointed out that the method or process here involved is to be carefully distinguished from that sometimes used in jigging practice in the crushing of middlings. In that practice the middlings are usually screened and the fine sizes sent to refuse, only the relatively coarse sizes being sent to a crusher and then back through the jig cell. This is done in an attempt to avoid any building up of fine refuse in the circuit which is just the opposite from what is here being done, in which the intent is to build the specific gravity of the separating medium by the recirculation of fine size middlings and then controlling the specific gravity of the separating medium by removing excess fine size middlings from the jigging circuit.

My hutching apparatus was particularly designed to assist in controlling the build up of high specific gravity separating medium in a system such as described by Byron M. Bird in his above identified patent. the amount of high specific gravity separating medium retained in the Bird system, when a two compartment jig is employed, is controlled by hutching the first jig cell. It has been found that sometimes it is impossible to hutch the material in the first cell fast enough to avoid excessive building up of the high specific gravity medium in the system. The apparatus of my invention makes it possible to reject in the system or circuit fine bone from the successive compartment 11 and to direct this rejected fine bone to refuse.

It is to be noted that in the method or process here involved there is no screening of the middlings and that all of the middlings from the second jig cell 11 may be returned to the jig feed. These middlings are preferably put through a crusher to reduce the large sizes thereof so that coal entrapped therein may be recovered. It will be seen, of course, that this crushing of the large size particles of middlings will increase the quantity of fine size particles in the middlings and that by controlling the hutching operations in the jig cells 10 and 11 that the excess of fines above that required to maintain the specific gravity of the separating medium at the desired level may be removed from the circuit and sent, by the elevator 22, to refuse.

In the system of Fig. 3 the operation of the first jig cell 10 is identical to that described above in connection with the system described by the flow chart of Fig. 2 and, in fact, were the valve 40 to be closed and the valve 39 to be opened, then this system would operate exactly as described in connection with the flow chart of Fig. 2. However, in this system the

valves

39 and 40 have the important roles of directing the high gravity hutch products of the hutch 25 of the second cell 11 into either or both of the elevator compartments 19' and 30 and this is an important factor in controlling the specific gravity of the high specific gravity separating medium in the jig.

In the system of Fig. 2 only middlings removed from the screen plate 24 are recirculated, but in the system of Fig. 3 some or all of the fine high gravity hutch material from the hutch compartment 25 may be mixed or blended with the middling particles removed from the screen 24 and recirculated to build up and control the specific gravity of the separating medium and this may be accomplished by adjusting the gates 49 of

valves

39 and 40. Thus, should it be desired to build up the specific gravity of the separating medium very rapidly allof the hutch Fundamentally,

material from the hutch compartment may be recirculated with all of the middling products from above the Screen 24, or any portion of this hutch product may be added, as necessary, to the middling products being recirculated to maintain the specific gravity of the separating medium at the desired level should all of the middling products when recirculated be insuflicient to maintain the specific gravity of the separating medium at the desired level.

From the foregoing it will be seen that l have provided an improved jig wherein substantially all back flow of fluid from its elevator compartments to its hutch compartments is prevented by a plurality of one-way check valves which permit high gravity hutch material to flow from the hutch compartments into the elevator compartments and that by reason of these check valves the efliciency of the jig is increased because the rate of return or fall of the separating fluid during the suction strokes in the jig cells 10 and 11 is not interfered with by the back flow of fluid from the elevator compartments to the hutch compartments and because all of the energy of the jig is utilized for causing substantially only the liquid in the jig cells to rise and fall cyclically.

It will also be seen that I have provided an improved multiple jigging apparatus wherein all of the hutch material from all of the hutch compartments may be removed and discarded as refuse and wherein all of the middlings from one of the jig cells may be removed from the jig to be returned to the jig for building up and maintaining the specific gravity of a high gravity separating medium in the jig, in which stratification of materials occurs, at a desired specific gravity.

It will be seen further that I have provided an improved apparatus including mechanism which may be adjusted so that any portion or all of the hutch products from one of the jig cells may be added to middlings removed from the screen in said cell to be recirculated for the purpose of aiding said middlings in building up the specific gravity of the high gravity separating medium in the jig in which Stratification of the materials being separated occurs.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended and applicant wishes therefore not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of the invention, what it is desired to secure by Letters Patent of the United States is:

l. A jig particularly adapted for use in a heavy media material separating system including a material treating compartment and a successive material treating compartment adapted to treat material being separated after it has been treated in said first named compartment, said first named compartment including a material supporting screen and a hutch compartment below said screen, an elevator compartment, material ejector means adjacent said screen controlling the ejection of material from said screen into said elevator compartment, means providing a fluid passageway between the bottom of said hutch compartment and said elevator compartment, a one-way check valve operable to restrict the flow of fluid from said elevator compartment into said hutch compartment and operable to permit free flow of fluid from said hutch compartment into said elevator compartment, said successive material treating compartment including a material supporting screen and a hutch compartment below said screen, a second elevator compartment, a second material ejector means adjacent said second named screen controlling the ejection of high gravity material from said screen into said second elevator compartment, means providing a fluid passageway between the bottom of said second named hutch compartment and each of said elevator compartments, and a one-Way check valve between each of said elevator compartments and said second named hutch compartment operable to restrict the flow of fluid from said elevator compartments to said hutch compartment and operable to permit free flow of fluid from said hutch compartment into both of said elevator compartments, at least one of said last named check valves being adjustable to restrict and to stop substantially all flow of fluid from said second named hutch compartment into one of said elevator compartments.

2. A jig particularly adapted for use in a heavy media material separating system including a material treating compartment and a successive material treating compartment adapted to treat material being separated after it has been treated in said first named compartment, said first named compartment including a material supporting screen and a hutch compartment below said screen, an elevator compartment, means providing a fluid passageway betwecn the bottom of said hutch compartment and said elevator compartment, a one-way check valve ope rable to restrict the flow of fluid from said elevator compartment into said hutch compartment and operable to permit free flow of fluid from said hutch compartment into said elevator compartment, said successive material treating compartment including a material supporting screen and a hutch compartment below said screen, a second elevator compartment, a material ejector means adjacent said second named screen controlling the ejection of high gravity material from said screen into said second elevator compartment, means providing a fluid passageway between the bottom of said second named hutch compartment and each of said elevator compartments, and a one-way check valve between each of said elevator compartments and said second named hutch compartment operable to restrict the flow of fluid from said elevator compartments to said hutch compartment and operable to permit free flow of fluid from said hutch compartment into both of said elevator compartments, at least one of said last named check valves being adjustable to restrict and to stop substantially all flow of fluid from said second named hutch compartment into one of said elevator compartments.

3. A jig particularly adapted for use in a heavy media material separating system including a material treating compartment and a successive material treating compartment adapted to treat material being separated after it has been treated in said first named compartment, said first named compartment including a material supporting screen and a hutch compartment below said screen, an elevator compartment, means providing a fluid passageway between the bottom of said hutch compartment and said elevator compartment, a one-way check valve operable to restrict the flow of fluid from said elevator com partment into said hutch compartment and operable to permit free flow of fluid from said hutch compartment into said elevator compartment, said successive material treating compartment including a material supporting screen and a hutch compartment below said screen, a second elevator compartment, a material ejector means adjacent said second named screen controlling the ejection of high gravity material from said screen into said second ele-' vator compartment, means providing a fluid passageway between the bottom of said second named hutch compartment and each of said elevator compartments, and a oneway check valve between each of said elevator compartments and said second named hutch compartment operable to restrict the flow of fluid from said elevator compartments to said hutch compartment and operable to permit free flow of fluid from said hutch compartmentinto both of said elevator compartments.

4. A jig particularly adapted for use in a heavy media material separating system including a material treating compartment and a successive material treating compartment adapted to treat material being separated after it has been treated in said first named compartment, said first named compartment including a material supporting screen and a hutch compartment below said screen, an

elevator compartment, means providing a fluid passage way between the bottom of said hutch compartment and said elevator compartment, a one-way check valve operable to restrict the flow of fluid from said elevator compartment into said hutch compartment and operable to permit free flow of fluid from said hutch compartment into said elevator compartment, said successive material treating compartment including a material supporting screen and a hutch compartment below said screen, a second elevator compartment, means providing a fluid passageway between the bottom of said second named hutch compartment and each of said elevator compartments, and a one-way check valve between each of said elevator compartments and said second named hutch compartment operable to restrict the flow of fluid from said elevator compartments to said hutch compartment and operable to permit free flow of fluid from said hutch compartment into both of said elevator compartments, at least one of said last named check valves being adjustable to restrict and to stop substantially all flow of fluid from said second named hutch compartment into one of said elevator compartments.

5. A jig including a material treating compartment and a successive material treating compartment adapted to treat material being separated after it has been treated in said first named compartment, said first named compartment including a material supporting screen and a hutch compartment below said screen, an elevator compartment, means providing a fluid passageway between the bottom of said hutch compartment and said elevator compartment, a one-way check valve operable to restrict the flow of fluid from said elevator compartment into said hutch compartment and operable to permit free flow of fluid from said hutch compartment into said elevator compartment, said successive material treating compartment including a material supporting screen and a hutch compartment. below said screen, a second elevator compartment, means providing a fluid passageway between the bottom of said second named hutch compartment and each of said elevator compartments, and a one-way check valve between each of said elevator compartments and said second named hutch compartment operable to restrict the flow of fluid from said elevator compartments to said hutch compartment and operable to permit free flow of fluid from said hutch compartment into both of said elevator compartments.

6. Material separating apparatus including amaterial treating compartment and a successive material treating compartment adapted to treat material being separated after it has been treated in said first named compartment, said first named compartment including a material supporting screen and a hutch compartment below said screen, an elevator compartment, means providing a fluid passageway between the bottom of said hutch compartment and said elevator compartment, a one-way check valve operable to restrict the flow of fluid from said elevator compartment into said hutch compartment and operable to permit free flow of fluid from said hutch compartment into said elevator compartment, said successive material treating compartment including a material supporting screen and a hutch compartment below said screen, means providing a fluid passageway between the bottom of said second named hutch compartment and said elevator compartment, and a oneway check valve between said second named hutch compartment and said elevator compartment operable to restrict the flow of fluid from said elevator compartment to said second named hutch compartment and operable to permit free flow of fluid from said hutch compartment into said elevator compartment.

7. Material separating apparatus including a material treating compartment and a successive material treating compartment adapted to treat material being separated after it has been treated in said first named compartment, said first named compartment including a hutch compartment, an elevator compartment, means providing a fluid passageway between the bottom of said hutch compartment and said elevator compartment, a one-way check valve operable to restrict the flow of fluid from said elevator compartment into said hutch compartment and operable to permit free flow of fluid from said hutch compartment into said elevator compartment, said successive material treating compartment including a hutch compartment, means providing a fluid passageway between the bottom of said second named hutch compartment and said elevator compartment, and a one-way check valve between said second named hutch compartment and said elevator compartment operable to restrict the flow of fluid from said elevator compartment to said second named hutch compartment and operable to permit the free flow of fluid from said hutch compartment into said elevator compartment.

8. A jig particularly adapted for use in a heavy media material separating system including a material supporting screen, a hutch compartment below said screen, a pair of elevator compartments communicating with said hutch compartment, material ejector means adjacent said screen controlling the ejection of high gravity material from said screen into one of said elevator compartments, and a pair of check valve means one between each elevator compartment and said hutch compartment for restricting fluid flow from said elevator compartments to said hutch compartment while providing for relatively free fluid flow from said hutch compartment to said elevator compartments, at least one of said check valve means being adjustable to restrict and to stop substantially all flow of fluid from said hutch compartment to the elevator compartment with which it is associated.

9. A jig particularly adapted for use in a heavy media material separating system including a material supporting screen, a hutch compartment below said screen, a pair of elevator compartments communicating with said hutch compartment, and a pair of check valve means one between each elevator compartment and said hutch compartment for restricting fluid flow from said elevator compartments to said hutch compartment while providing for relatively free fluid flow from said hutch compartment to said elevator compartments, at least one of said check valve means being adjustable to restrict and to stop substantially all flow of fluid from said hutch compartment to the elevator compartment with which it is associated.

10. A jig particularly adapted for use in a heavy media material separating system including a material supporting screen, a hutch compartment below said screen, a pair of elevator compartments communicating with said hutch compartment, and a pair of check valve means one be tween each elevator compartment and said hutch compartment for restricting fluid flow from said elevator compartments to said hutch compartment while providing for relatively free fluid flow from said hutch compartment to said elevator compartments.

References Cited in the tile of this patent UNITED STATES PATENTS 2,281,530 Strawn Apr. 28, 1942 2,487,845 Bird Nov. 15, 1949 2,573,503 Smith Oct. 31, 1951