Water separation system, method and apparatus for construction debris

This Appln claims benefit of Prov. No. 60/118,194 filed Feb. 1, 1999.

BACKGROUND OF THE INVENTION

a) Field of the Invention

The present invention relates generally to a system for the separation of lower density debris from higher density debris, and more particularly to such a system, method and apparatus which is particularly adapted to separate construction debris where the low density fraction in general has a density lower than the density of water, and the high density fraction has a density substantially greater than water. More particularly, this would be particularly adapted for use where a large percentage of the low density fraction comprises wood, and also a large portion of the high density fraction comprises rock, cement, metal and other materials commonly found in building structure or other structures.

b) Background Art

It is common practice that when a building structure is being demolished, the debris is simply gathered somewhat indiscriminately into piles and then carried to the dumpsite. Particularly in more recent years, it has been found to be more economical to simply use bulldozers, back hoes, demolition balls, explosives, etc. Depending upon the building or other structure being demolished, there may be a very high percentage of wood or other low density material, or a relatively small amount of the same.

One of the challenges regarding disposal of construction debris is how to recycle or process this material so that it could be used for some useful purpose, instead of just being accumulated in the dumpsite as waste material. Such debris, if properly sorted and/or processed, could be used for land fill, or road beds and this may be accomplished by crushing the rock or rock like material into smaller particles. However, organic material such as wood, is not desirable for a land fill. First, the organic material would decay over time and thus have its load bearing capability degraded. Second, quite often wood pieces come in sections of a two by four, etc., and when placed in a land fill these could protrude upwardly from the surface, etc.

With regard to the wood component of the construction debris, if properly separated, this could be recycled into a variety of useful products, such as ground cover, fuel, etc.

The practical problems in the existing separating processes are often too expensive relative to the economic return that might be realized by productive use of the separated and/or processed materials. The sheer mass and volume of construction debris generally makes manual separation uneconomical. Attempted separation by machinery, (e.g. back hoes and/or bull dozers) involves not only the expense of operating the machinery, but the separation process itself is difficult to be accomplished effectively.

It has been known for many decades, if not centuries, that the separation of material in accordance with its density could be achieved by flotation techniques, where the liquid medium has a specific gravity between that of the two fractions which are to be separated (i.e. where one of the fractions to be separated has a density greater than the liquid medium and the other density less than this liquid medium). Such flotation techniques have been employed in a wide variety of commercial applications.

Accordingly, it is understandable that there have been attempts to use flotation techniques to separate the low density fraction (which would generally comprise in large part wood and possibly other material having a specific gravity less than water) and the high density fraction (comprising stone, concrete, metal pieces, etc.). To the best knowledge of the applicant, the efforts to effectively accomplish such separation by flotation have only marginal success. One method is to provide an upwardly open tank which is filled with water. The construction debris is deposited into the tank, and two back hoes are operated to remove the separated fractions. One back hoe is used to skim the top of the water to remove the wood particles, while the other back hoe is used to remove the denser particles which fall to the bottom of the tank.

Another method and apparatus is disclosed in two U.S. patents (U.S. Pat. Nos. 5,240,114 and 5,110,454). In both of these patents, there is shown a system where a mixture of rock, soil particles and wood is introduced into a water tank. Near the upper water level, a plurality of jet nozzles direct streams of water through the mixture to remove the lower density particles so that these flow toward a slanted baffle

66

, thence over the baffle into an area where some of the wood particles float, and some descend downwardly onto a wood piece conveyor

150

. This conveyor removes the wood pieces from the water. The rocks from the mixture drop down onto a rock receiving portion

82

where there is a rock conveyor that removes these from the water tank.

A search of the patent literature has disclosed a number of other patents which relate generally to flotation/separation techniques for variety of industrial environements. These are described below.

U.S. Pat. No. 5,373,946 (Olivier) discloses a separating apparatus which utilizes what is termed a “scrolled” barrel. It is pointed out that these are classified as mono- or bi-directional. In the mono-directional barrels both of the floats and sinks move in the same direction and exit in the same end of the barrel. The bi-direction barrels have the floats and sinks move in opposite directions. It is pointed out that in the bi-directional barrel the raw feed is introduced near the place where the sinks are evacuated and the only practical way of evacuating the sinks is by means of a scrolled cone. However, there is a very annoying problem which the patent points out as up to the time of this patent never been solved in a satisfactory way, namely, how to prevent a small percentage of the floats from working their way toward the sink side of the barrel and eventually reporting with the sinks being screwed up to the sinks evacuation cone. This is solved by having the discharge end of the rotating drum formed having a fursto-conical configuration, and the larger diameter input end has a diameter greater than that of the main central barrel. Also, there is a barrier positioned at the front side of the main central portion to prevent the floats from proceeding toward the high density end. Further, the high density discharge portion has its large diameter end of a diameter greater than that of the central portion.

U.S. Pat. No. 5,169,005 (Beane) shows a separator in which material passes into a chamber that is provided with paddle drum

20

. The material enters through chute

32

, and the lighter material is impelled across the surface of the fluid by additional fluid supplied under pressure through nozzle

16

. The lighter material passes out through chute

40

. The paddles drum

20

, brings up the heavy material that exits through

78

.

U.S. Pat. No. 5,104,047 (Simmons) shows a waste treating system in which material entered through hopper

36

, and the floating material is driven into a chopping or milling means

34

, by fluid injected through jets

62

. The heavier accumulates on the bottom and is removed by conveyor

70

.

U.S. Pat. No. 4,944,869 (Lyakov et al.) shows a system in which a mix of crushed storage battery material is separated into constituent material by a series of flotation units as shown on sheet

5

. The separator unites are formed of rotating flotation unites in which the lighter weight materials pass through, and the heavier materials separate out as them material moves through the system.

U.S. Pat. No. 3,392,828 (Muller) shows a separator in which a mix of materials enters the system via

2

, and pass into a fluid fill chamber. There is a rotating mesh drum with vanes

12

, operating in the fluid body. The drum is slanted relative the surface of the fluid so that at the input end the fluid is below the entrance, but at the output end the fluid flow out. Small heavy, particles

7

fall through the mesh, while large heavy bodies

9

, are lifted by the vanes so as to drop on chute

10

, and roll out of the separator. The light material which floats on the fluid passes out on the right below chute

10

.

U.S. Pat. No. 3,101,312 (Brinkmann) shows a separator in which the materials to be separated enter through weir

4

, and are carried by vanes

10

to the top of the device where the lighter material is carried out through scoop

6

, while the heavy material accumulates at the body.

U.S. Pat. No. 2,700,466 (Logue et al.) shows a pair of flotation separators

26

, and

27

. The material to be separated enters section

26

, through chute

50

, and falls into fluid body

54

, where the fluid carries the floating light material out through discharge chute

62

. The heavy materials are raised by fins

42

, and passes into section

27

. In section

27

, the middle weight material floats on the fluid and runs out opening

36

a

, to chute

89

. The heaviest material is carried up through

69

, where it passes out through chute

86

.

U.S. Pat. No. 2,608,716 (Harris) shows in

FIG. 3

, a device that separates oyster meat from shell fragments. The meat with shell material are carried by belt

31

, to the flotation bath where the meat floats and is propelled by fluids from nozzles

43

, toward belt

36

. The small fragments fall to belt

44

, and are carried off.

U.S. Pat. No. 384,861 (Melkersman) shows a device that separates good grain from bad, as well as other light materials. The materials to be separated enter through “I”, and fall into the water. The heavy material moves down to the large end of the rotating cylinder and is lifted by buckets “G”, to fall onto screen “H”. the light material floats out over the lip of the cylinder into screen “H”.

Accordingly it is an object of the present invention to provide a separation system, method and apparatus which is particularly adapted to effectively accomplish the separation of debris into lower and higher density fractions. More particularly, the present invention is particularly adapted to solve the various challenges that are involved in the separation of construction debris, where there is a desirable balance of advantages, such as accomplishing the process efficiently, at reasonable cost, with high production, and reliably.

SUMMARY OF THE INVENTION

In the method of the present invention, there is provided a rotatably mounted drum which comprises a surrounding side wall and front and rear end walls having, respectively, front and rear discharge openings. The drum defines a processing chamber with a lower water containing chamber region, having an upper level at an upper water level in the region and a lower level at a lower side wall portion at the region. At least part of the water containing chamber region is positioned at a level below lower portions of the front and rear openings. The drum has a high density debris conveying structure which is arranged to engage high density debris at a lower part of the water containing chamber region. The water containing chamber region is filled with water to form a body of debris processing water in the chamber region.

Then the debris is delivered into the processing chamber at a receiving location at the water containing chamber region.

Additional water is delivered into the processing chamber at a water discharge location forward of the debris receiving location. This additional water is delivered at a location adjacent to the upper level of the water containing region in a rearward direction generally aligned with the upper level of body of water at a sufficiently high velocity into an upper high velocity low density separating zone. This causes the low density debris in that zone to move from the debris receiving location rearwardly to be discharged at the rear discharge opening. The high density debris that is delivered to the receiving location descends through the upper high velocity low density separation zone toward the lower level of the water containing region.

The drum is rotated to cause the conveying structure to move the high density debris at the lower part of the water containing chamber region to a forward end of the drum. Then the high density debris is discharged through the front opening.

In a preferred form, there is a water discharge region at the water discharge location extending across the upper level of the water containing chamber region. The method further comprises discharging the additional water only at a portion of the water discharge region so that the additional water creates with the surrounding water a turbulent downstream flow. Desirably, this is accomplished by discharging the water through a plurality of nozzles to form a plurality of water jets. These nozzles are positioned in the preferred form on both sides of a center location of the water discharge region. As a further region, there is at least one discharge nozzle at a location beneath the water discharge region to direct a flow of water in a rearward direction.

The preferred configuration of the nozzles is that each nozzle has an elongate nozzle opening with a width dimension greater than its depth dimension, and with an elongate axis of each of said discharge openings being generally horizontally aligned. This results in high velocity flow patterns which expand laterally at a greater rate than vertical expansion.

In the preferred form, the water is discharged through the nozzles at a velocity of at least one foot per second, more desirably at least four feet per second, and also desirably at a velocity of at least ten feet per second. In a preferred embodiment the range is between ten to fifteen feet per second. It is to be understood that the velocity within the broader scope could be at 2, 3, 5, 7, 8, and 9 feet per second. Further the velocity could be increased by one flow per second increments up to fifteen feet per second which would be a preferred velocity, and through one foot per second velocity increments up to 20 or 25 feet per second. Desirably, the rear discharge opening is defined by a generally circular perimeter rim and is generally centered on an axis of rotation of the drum. The water flowing out of the rear opening is over a curved rim segment, and the water is delivered at a sufficient flow rate so that the curved segment over which the water flows is at least thirty degrees. At a higher velocity, the segment over which the water flows is at least forty five degrees, and with yet higher velocity at least sixty degrees.

Desirably, the low density debris is moved by the water flow from the debris receiving location into a predischarge zone section which is defined by an inwardly and upwardly tapering rear end wall leading to the rear discharge opening and through which the water accelerates to be discharged through the rear discharge opening. Desirably the rear edge portion of the rear end wall is aligned with the circular perimeter rim of the opening. This rear end wall is desirably configured approximately in a fursto-conical configuration.

The water and load density debris are discharged from the rear opening onto a low density debris receiving discharge structure having flow through openings through which the water falls to separate the low density debris from the water. Desirably, this low density debris receiving discharge structure comprises a surrounding fursto-conical side wall member with a smaller inlet opening and a larger outlet opening. This low density debris receiving discharge structure is rotated to tumble the low density debris to facilitate discharge of the same. Desirably this discharge structure is connected to the drum so as to be rotatable therewith.

Water and high density debris are discharged from the rear opening onto a high density debris receiving discharge structure having flow through openings through which the water falls to separate the high density debris from the water. This high density debris receiving discharge structure comprises a surrounding a fursto-conical side wall member with a smaller inlet opening and a larger outlet opening which is rotated to tumble a low density debris to facilitate discharge of the same, and which is desirably connected to the drums so as to be rotatable therewith.

The high density debris is discharge by rotating a discharge structure to engage the high density debris at the forward end of the drum and carry such high density debris to be discharged through the front discharge opening. Desirably the discharge structure is mounted to the drum so as to be caused to rotate by rotation of the drum. Further, in the preferred form, the discharge structure comprises a plurality of paddles which are circumferentially spaced and which engage the high density debris at a lower location to carry it to a higher location and cause discharge of the high density debris through the front discharge opening.

The high density conveying structure is positioned at an inside surface of the drum and extends radially inwardly therefrom with a rearward to forward slanting surface portion which engages the high density debris to cause forward movement of the high density debris.

The apparatus of the present invention has in large part been described in the above text relating to the method of the present invention. Thus, as indicated above, the apparatus comprises a rotatably mounted drum having the surrounding side walls, the front and rear end walls with the front and rear discharge openings, and also the high density conveying structure. There is support and drive section to support and rotate the drum.

There is a debris delivering section to deliver the debris into the processing chamber at a receiving location at the water containing chamber region. In a preferred form, this debris delivering section comprises a conveyor extending through one of the front and rear openings in the drum (desirably extending through the rear opening), and a hopper delivering the debris onto the rear end of the conveyor which then carries it inwardly above the water level in the processing chamber to deposit the debris off the front of the conveyor and onto the surface of the water at the receiving location.

There is also a water supply and delivery section which discharges water through the aforementioned nozzles (in the preferred form). In the overall system, there is a pair of settling tanks, and water is drawn from the settling tanks by a pump which in turn directs the water through a control valve and thence through a conduit section that extends through one of the front and rear openings in the drum. The conduits are desirably supported from the conveyor. The conduits extend outwardly to the water level and then terminate in rearwardly directed water nozzles.

Most all of the processing water is discharged through the rear opening along with the low density debris. The water discharged from both the rear and the front opening is collected in a tank positioned beneath the drum, and it is directed from this tank to the settling tanks where sludge and small particles settle out.

Other features and components of the present invention are described in the prior text under “Summary of the Invention” and also are described in more detail in the full text that follows.

DESCRIPTION OF THE DRAWINGS

FIG. 1

is a schematic top plan view of the overall system of the present invention;

FIG. 2

is a side elevational view of the separating assembly of the present invention;

FIG. 3

is a cross sectional view, taken along a vertically aligned longitudinal plane through the longitudinal center axis of the separating assembly;

FIG. 4

is a sectional view similar to

FIG. 3

, illustrating the separating assembly in operation;

FIG. 5

is a rear elevational view thereof;

FIG. 6

is a front elevational view thereof;

FIG. 7

is a transverse sectional view taken along line

7

—

7

of

FIG. 4

;

FIG. 8

is a sectional view taken along line

8

—

8

of

FIG. 4

;

FIG. 9

is a view taken along the same section line as

FIG. 8

, but showing only the outer drum and the front discharge section of the present invention;

FIG. 10

is a schematic front elevational view of the separating and conveying drum of the present invention, illustrating the water level and the discharge pattern of the water through the rear end opening of the apparatus;

FIG. 11

is a schematic rear elevational view of the rear lower right hand segment of the rear discharge opening, showing the water level at different locations;

FIG. 12

is a schematic plan view taken along a horizontal plane extending through the center axis of rotation, and illustrating the flow pattern from the water discharge nozzles into the processing chamber;

FIG. 13

is a sectional view taken along a vertical plane through the center axis of rotation of the apparatus, showing the lower portion of the separating drum and showing the flow pattern from the jets to the discharge opening; and

FIG. 14

is a sectional view similar to

FIG. 12

, but showing various dimensions and dimensional relationships of the separating drum of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

a) Overall Description of the System

10

With reference to

FIG. 1

, the overall system

10

of the present invention is illustrated somewhat schematically in top plan view. There is an initial conveyor section

12

on which the construction debris to be sorted is placed, and this conveyor

12

delivers the construction debris into a rotating trommel

14

which is or may be of conventional design. This initial conveyor

12

can be made up of one or more conveyor sections, with the first conveyor receiving the construction debris and delivering it onto a second conveyor in a manner so that the material can be spread out more evenly. Some initial sorting may be done (e.g. by hand) on this first conveyor to remove objects that desirably should not proceed through the system.

The trommel

14

is arranged so that in the first infeed section of the trommel, there are small openings through which the dirt and small gravel falls to be collected and delivered to a collecting location. This function is accomplished by a conveyor

16

which receives this dirt and small gravel and takes it to a collecting location.

The downstream portion of the trommel

14

has around its side larger openings in its surrounding sidewall, possibly one foot in diameter, where the medium sized material which is to go through the separation process passes through the openings in the trommel

14

, to be delivered onto a feed conveyor

18

which in turn carries this larger material to the separating assembly

20

of the present invention.

This separating assembly

20

is the more significant part of the overall system

10

and will be described in greater detail later herein. This separating assembly

20

very effectively separates the construction debris into a more dense fraction or component which is made up of rock, metallic pieces, etc., and a lower density fraction or component, which comprises wood and other material of lower density. The higher density fraction is carried from the separation assembly

20

by a high density debris conveyor

22

to a collecting location, while the lower density fraction or component of the construction debris is carried away by a low density component conveyor

24

.

Then there is a final disposal conveyor

26

which receives material at two locations. First at a rear location, the larger size construction debris that does not pass through the openings in the trommel

14

is delivered onto the rear end of the final conveyor

26

. Also, the low density component conveyor

24

delivers the low density material (wood or other low density material) onto this same conveyor

26

. The material delivered to this conveyor

26

can be disposed of in various ways. For example, there can be various sorting locations

28

along the length of the conveyor

26

to remove certain portions of the debris, such as, for example, wood pieces. Then the remaining debris is delivered to an end location. This may comprise larger rocks or objects which can be disposed of in various ways, such as being crushed and used for roadways or landfill, etc. The wood fraction can be recycled in various ways.

Finally, there is a pair of large settling tanks

30

. As will be disclosed subsequently in the more detailed description herein, water is delivered through the separating assembly

20

at very high volumetric rates (e.g. as high as 2000 or 2500 gallons per minute). Thus these two tanks

30

are relatively large (e.g. each in a preferred design, each being as large as fifty feet long by eight feet) and the water used in the separating assembly

20

is cycled through the settling tanks

30

to let dirt and other material settle out. The water is continuously directed from the tanks

30

back to the separation assembly

20

.

In a full commercial operation, the overall length dimension of the initial conveyor

12

plus the trommel

14

could be as long as approximately 200 feet, and the final conveyor

26

could be as long as 100 feet. In the arrangement of the present invention, depending upon the type of construction debris that is being processed, the overall capacity of the whole system could be as much as 60 to 200 tons of debris in an hour, and the portion of the construction debris that is passed through the separating assembly

20

could be as great as 30 to 100 tons per hour.

b) Overall Description of the Separating Assembly

20

Reference is initially made to FIGS.

2

,

3

and

4

. This separating assembly

20

comprises:

i) a separating section

32

which is a unitary structure where the separating process takes place and from which the high density and low fractions are delivered to their respective conveyors

22

and

24

;

ii) a construction debris feed section

34

which comprises a hopper

36

which receives construction debris from the conveyor

18

, and a conveyor

38

which receives the debris from the hopper

36

and delivers the debris to the interior of the separating section

32

;

iii) a water supply and discharge section

40

which continuously delivers water at a large volumetric flow rate into the separating section

32

which cooperates with the other components in the separating process to move the low density fraction or component to be discharged from the separating section

32

, and recycles the water through the settling tanks

30

(These settling tanks

30

can be considered part of the water supply and discharge section

40

);

iv) the support and drive section

41

that (as its name implies) provides support for the separating section

32

, rotates the separating section

32

.

The separating section

32

is, as indicated above, a rotably mounted unitary structure. This section

32

comprises a separating and conveying drum

43

which has a generally cylindrical configuration and defines a processing chamber

44

. This separating section

32

has a rear end portion

46

, a front end portion

48

and a longitudinal center axis

50

about which the separating section

32

rotates. The drum

43

has a generally circular rear end opening

52

through which the low density debris and the major part of the processing water is discharged, and a front opening

54

through which the higher density debris fraction is discharged, with both openings

52

and

54

being centered on the longitudinal center axis

50

.

At the rear end

46

there is a low density discharge structure

56

which has a general frusto-conical configuration and comprises a rear circular perimeter edge

58

of a larger diameter, and a front circular perimeter edge

60

of a smaller diameter at the opening

52

. There is a plurality of elongate bars

62

which are fixedly connected between the perimeter edge portion

60

and

58

in a rearwardly expanding fursto-conical configuration. These bars

62

are spaced from one another to form elongate slots of about ⅜ to ¾ inches to permit the water from the rear opening

52

to pass therethrough.

There is a front high density discharge structure

64

positioned at the front end

48

of the separating section

32

, and this also has a generally fursto-conical configuration, with a rear circular perimeter edge portion

66

at the front opening

54

and a forward circular perimeter edge portion

68

having a larger diameter than the perimeter edge portion

66

. Also, there is a plurality of bars

70

extending between the two perimeter edge portion

66

and

68

in an expanding fursto-conical pattern, spaced from one another by about ⅜ to ¾ inches. These discharge structures

56

and

64

are significant in the present invention (particularly the rear structure

56

) in that these separate the low and high density debris components from the water and enable the water to be recirculated. As part of the water supply section

42

, there is a water recovery tank

72

to receive the major part of the water that passes through the rear discharge structure

62

and also the smaller amount of water that passes through the forward discharge structure

64

.

The aforementioned separating and conveying drum

43

comprises a cylindrical side wall

73

, a rear end wall

74

which has an overall fursto-conical configuration which converges in a rearward direction at an angle that is about 45 degrees from the longitudinal axis

50

, comprising a front edge portion

76

of a larger diameter and a rear edge portion

78

of a smaller diameter and which defines the rear opening

52

. The wall

74

itself is solid and extends between its two perimeter edge portions

76

and

78

. The perimeter edge portion

76

is fixedly connected to the cylindrical side wall

73

a moderate distance forwardly of the rear edge

79

of the side wall

73

. The rear perimeter edge

78

is coincident with the front edge portion

60

of the rear discharge structure

56

.

The drum

43

has a front wall

80

which has a planar configuration aligned transversely to the longitudinal axis

50

, and the aforementioned discharge opening

54

is defined by a perimeter circular edge

81

in the front wall

80

. Immediately behind the front wall

80

is a high density debris collecting structure

82

which comprises four planar longitudinally aligned planar paddles

84

which extend radially outwardly, at right angles from each other, from the center axis

50

. Each paddle

84

has an outer edge

86

fixedly attached to the forward part of the cylindrical side wall

74

, an inner edge

88

, a rear edge

90

, and a front edge

92

fixedly connected to the front wall

80

. Each paddle

84

has a plurality of through openings

94

along the rear portion thereof to permit the passage of water therethrough.

At the center of the collecting structure

82

there is a discharge cone

96

having a rear circular edge

98

, a front point

100

, and a side wall

102

having a generally fursto-conical shape, which is concavely curved relative to reference coincident with the longitudinal axis

50

. Thus, the wall

102

, as seen in cross section in

FIG. 4

, has a concave curve which helps direct the high density debris components into the front discharge structure

64

. The arrangement of this discharge structure can best be seen in the sectional views shown in

FIGS. 8 and 9

.

The separating and conveying drum

43

also comprises a conveying structure

104

positioned within, and fixedly connected to, the interior surface

106

of the drum side wall

73

. In the particular configuration shown herein, this conveying structure

104

is an elongate planar member having a spiral configuration, so that rotation of the drum

43

in the appropriate direction causes the conveying structure

104

to move the higher density material which collects at the bottom of the drum sidewall

73

forwardly in the drum chamber

44

. Such conveyors are sometimes referred to as “scroll conveyors”, and these can have various configurations, such as having a continuous helical member, two or more continuous helical members with the flights spaced longitudinally from one another, or a possibly conveying section which is not formed in a continuous elongate spiral member, but in spiral segments. In this particular configuration, the conveying structure

104

is formed as one continuous spiral that makes two complete revolutions, and has a rear starting end location

108

adjacent to the front edge

76

of the rear wall

74

and a front end location at

110

adjacent to the collecting structure

82

.

It can readily be see from examining

FIGS. 4

,

8

and

9

that as the high density debris

112

collects in the bottom of the drum

43

, the rotation of the drum

43

causes the conveying structure

104

to move the high density debris

112

to a forward location where it is engaged by the paddles

84

to be carried upwardly (see FIG.

8

), with further rotation of the drum moving the paddles

84

further upwardly and causing the debris

112

(see

FIG. 9

) to tumble down the surface of the paddle

84

toward the center cone

96

to cause the high density debris

112

to be discharged in a forward direction into the front discharge structure

64

.

The aforementioned support and drive section

42

comprises a base frame

114

which provides support for the water receiving tank

72

, and also for the rotating separating section

32

. More specifically, this support and drive section

42

comprises a plurality of circular drive members

116

which can conveniently be provided in the form of rubber automobile or truck tires

116

, one or more of which is driven by a suitable motor (electric powered, diesel powered, etc.). It can be seen (and as is evident from the foregoing description) that the separating section

32

is a unitary structure which comprises basically the separating and conveying drum

43

and the discharge structures

56

and

64

rotate as a single unit.

The water supply and discharge system

40

will now be described with reference being initially made to

FIGS. 2 and 5

. As indicated previously in the overall description of the system

10

, and with reference to

FIG. 1

, there are provided two relatively large settling tanks

30

for the relatively large amount of water which is used in the operation of the separating section

32

. There is a main feed line

118

which directs water from either or both of the tanks

30

to the location of the separating section

32

. This line

118

(see

FIG. 5

) feeds into two longitudinally extending supply lines

120

, which are supported from the structure

121

of the aforementioned conveyor

38

. These two supply lines

120

extend longitudinally in a forward direction to reach through the rear main opening

52

and extend all the way to a location just in front of the saddles

84

of the discharge structure

82

.

These two supply lines in turn lead to a manifold section

122

(see FIG.

7

). This manifold section

122

comprises two vertically oriented conduit sections

124

which are downward extensions of the aforementioned supply lines

120

. At an upper location of each of the lines

124

there is a downwardly and laterally outward extending line

126

, and also there are two additional lines

128

which extend downwardly and in a slant toward a central location to join to a lower central tube section

130

. The two lines

124

both continue downwardly to terminate at a lower location.

With further reference to

FIG. 7

, it can be seen that the two outer tubes

126

terminate at the lower end in rearwardly directed outer nozzles

132

which are positioned near to the inner edge portion of the conveyor

104

. Then the two tube portions

124

terminate in inner nozzles

134

which also face rearwardly and are each positioned about midway between its related nozzle

132

and the longitudinal center axis

50

. Then the middle tube

130

terminates at its lower end in a rearwardly facing discharge nozzle

136

which is centrally located. It will be noted that he four nozzles

132

and

134

are located at a level of the water which is indicated at

138

. The central nozzle

136

is at a lower location which is about midway between the water level shown at

138

and a lowermost location

140

of the inner surface

106

of the drum sidewall.

c) General Description of the Overall Operation

In this section the overall operation will be given in more general terms to explain the functions of the main components. Then in the section that follows, there will be described in more detail certain distinctive features of the present invention relating to the sorting and discharge of the low density fraction of the construction debris and the water.

Reference will first be made back to

FIG. 1

, where there is shown the conveyor

12

carrying the construction debris to the trommel

14

with the dirt and small particles being separated out and deposited on the conveyor

16

, the very large objects passing through to the discharge end of the trommel

14

and being deposited on the end conveyor

26

, and various objects of an intermediate size being deposited upon the conveyor

18

which in turn leads to the separation assembly

20

. This material from the conveyor

18

is delivered to the hopper

36

(see

FIG. 2

) to be deposited upon the rear end of the conveyor

38

which carries the construction debris in a forward direction through the rear opening

52

in the separating section

32

. The front discharge end

142

of the conveyor

38

is located a moderate distance forwardly from a longitudinally center location in the drum

43

.

In

FIG. 4

, the construction debris is represented as smaller and larger rocks, some metal objects, pieces of wood, etc. Before the separating process beings, the drum

43

is filled with water up to the level shown at

138

in

FIGS. 3

,

4

and

7

. It will be noted that this level

138

is indicated as being at (or at most just slightly higher than) the level of the lowermost location

143

of the rear perimeter edge

78

of the rear end wall that defines the opening

52

. Thus a small amount of the water is shown flowing outwardly through the opening

52

. It will also be noted that the diameter of the front end opening

54

is smaller than the diameter of the rear opening

52

so that the lower edge

144

of the opening

54

is above the lowermost edge portion

143

of the rear opening

52

.

When the separating operation beings, and the construction debris is just started to be loaded into the hopper

36

and onto the conveyor

38

, and with the drum

43

being filled with water up to the level indicated at

138

or slightly, the valve

145

controlling the flow into the main supply line

118

is moved to an open position, and the pump

146

is energized to start pumping the water into the system at a sufficiently high volumetric rate. At the same time, the motor which rotates the separating section

32

is energized to cause the entire separating section

32

to being rotating in a direction to cause a forward conveying structure

104

(in a front view, taken from the left of

FIGS. 2

,

3

and

4

this direction of rotation would be clockwise).

As the construction debris

112

drops off the discharge end

142

of the conveyor

38

as indicated at

148

, the higher density material (generally rock, metal pieces, etc.) drop to the lower part of the drum

73

, as indicated at

150

. The material of lower density (e.g. wood) indicated at

152

floats on the water surface. The debris at

150

is moved by the conveying structure

104

forwardly to the location indicated at

154

in FIG.

4

and also in FIG.

8

. With the section

32

moving in a clockwise direction (as seen from a front location), the movement of the paddles

184

(see

FIG. 9

) carries the debris upwardly, as indicated at

156

so that it tumbles down along the upper slanted surface of each of the paddles

84

to drop into the area defined by the center cone

96

and the upper paddles

84

to pass through the front opening

54

and onto the front discharge structure

64

.

At the same time, the water flowing through the nozzles

132

,

134

and

136

and into the drum chamber

44

not only raise the level of water into the drum above the level indicated at

138

, but also urge the flow of water in a rearward direction to facilitate the movement of the floating material through the rear opening

52

and onto the rear discharge structure

56

.

The high density fraction of the debris falls into the rotating rear discharge structure

64

is discharged onto the conveyor

22

, and the water entrained in such higher density fractions falls between the bars

70

and into the receiving tank

72

.

As the lower density fraction of the construction debris exits through the opening

52

, there is also a high volumetric flow rate through this opening

52

. (The water level shown at

138

in

FIG. 4

is shown as being somewhat lower than what it would be in full operation as shown in FIG.

13

). The water falls through the spaces between the bars

62

of the rear discharge structure

56

, and the rotating action of the rear structure

58

causes this lower density debris to be deposited onto the conveyor

24

.

The arrangement of each of these discharge structures have several advantages. First, the water is effectively separated from the high and low density components to be collected in the tank

72

and recirculated back to the separating section

43

. Second, with these discharge structures

56

and

64

being made part of the separating section

43

so as to be rotating during the separating process, the movement of both debris components to their respective conveyors is facilitated by the tumbling action imparted to the debris fractions.

d) More Detailed Description of the Sorting Out and Removal of the Low Density Fractions

Earlier in this text, it was mentioned that the manner in which the discharge of the lower density debris through the opening

52

is accomplished is significant in the present invention. To explain this, reference will be made to

FIGS. 10-13

.

For convenience, in the following description the term “low density fraction of the debris” will simply be referred to as the “wood pieces”, and the high density fraction of the debris will be referred to as the “rocks”, since these two materials in a large number of instances comprise the preponderance of the construction debris. This is done with the understanding that the term “wood” would include other construction debris having low density that would be separated with the wood and the “rocks” include other high density debris.

FIG. 10

is a semi-schematic rear elevational view looking toward the rear opening

52

through which the wood is discharged along with almost all of the water. In the preferred embodiment described herein, the diameter of the inner rear opening

52

defined by the perimeter edge

60

is six feet, while the diameter of the inside surface

106

of the drum

43

is twelve feet. If there is no flow of water in the drum, then as shown in

FIG. 10

the water level would remain at the level

160

which is at the same height as the lowermost edge portion

162

of the rim

60

. However, at such time as the separating assembly

20

is put into operation, and water is delivered into the processing chamber

44

in the drum

43

(the water being indicated at

163

), then the water level is raised in the chamber

44

approximately to an operating level which in

FIG. 10

is indicated at

164

. (This can vary depending on the volumetric rate of the water flow into the chamber

44

, the rate at which the debris is delivered, the size and shape of the wood items, etc.

Before getting into the details of the flow pattern of the water in the present invention, it is believed that it would be helpful to review some general principals regarding the hydrodynamics of water flow.

We begin by again looking at

FIG. 10

, and it can be seen that the lower area of the chamber

44

of the drum

43

that is filled with water during the operation of the machine, has a cross sectional configuration of a segment of a circle which is bound at the top part by the line

166

(at the water level

164

) extending between the right and left point a and b, and also by the lower curved portion

168

of the lower portion of the wall of the drum

43

. If the diameter of the drum is at twelve feet, then the cross sectional area of the area (i.e. perpendicular to the longitudinal axis

50

) of the drum in which the water is contained is calculated to be about 22 square feet. (This will vary depending on the level of the water at

166

.

The cross sectional area of the water being discharged at

162

would be a very small fraction of this. To explain this, reference is made to

FIG. 11

which shows only the right lower ninety degree portion of the rim

78

defining the rear discharge opening

52

, and the arrow at

170

shows the level of the water when it extends up a little bit above the forty degree location as indicated on FIG.

11

. When the water is at this level, the cross sectional area indicated

162

would be at 1.8 feet. On the other hand, if the water level is at the location indicated at

172

in

FIG. 11

(i.e. the 30 degree location), that cross sectional area would be about 0.8 square feet. The volumetric flow rate is equal to the cross sectional area of the flow times the average velocity. If the height

164

increases, the pressure differential from the level

164

to the lowermost point

162

becomes greater (thus accelerating the flow to a greater higher velocity) and also the cross sectional area increases, so the volumetric flow rate of water increases substantially when the water level rises from the level at

172

to the level at

170

.

To explore another facet of the hydrodynamics of fluid flow, reference is now made to FIG.

12

. As indicated in

FIG. 12

, the inflow of water is through five nozzles, namely the four nozzles

132

and

134

which are closer to the level of the water, and also a single center nozzle

136

which is at a somewhat lower position. For the moment let us assume that the drum

43

is much longer, that these five nozzles are at a location much further upstream, and also that their discharge cross sectional areas are much larger so that the flow of the water has very little turbulence. With the cross sectional area of the drum

43

being uniform, while the water may experience some small eddy currents adjacent to the drum surface

43

, for the most part it would be might be what called “quiescent”. However, as the flow of water approaches the converging fursto-conical rear end wall

74

and the exit opening

52

, for the same volumetric flow to go through this opening

52

, it becomes necessary for the velocity of the water to increase substantially.

Some people have a mistaken notion that as water is flowing down an upwardly open channel and then reaches a narrowing restriction, the water will rise upwardly as it reaches the restriction so that the restricted portion can accommodate the flow of water. However, this does not happen. What does occur is that as the water approaches the constriction, the surface of the water actually becomes lower as the water enters into the restriction and is lowest at the narrowest point in the restriction. Then as it passes out of the restriction to a broader (greater area) channel, the level of the water rises.

In the preferred embodiment of the present invention described herein, the flow of water has a very high volumetric flow rate, a preferred range being two thousand gallons to two thousand five hundred gallons per minute or higher. On the assumption that there are 7.5 gallons of water for each cubic foot of water, and assuming that the volumetric flow during normal operation of the apparatus is two thousand to two thousand five hundred gallons per minute, then the volumetric flow rate through the separating section

32

is 4.4 to 5.5. cubic feet per second. If we are to assume that the level of the water in the containing area of the 12 foot drum is at approximately a level shown at

FIG. 10

, which would make this cross section area at least about twenty square feet, and if the flow were toward the exit opening

50

were undisturbed, then the average velocity of the water (assuming that the flow rate is about five cubic feet per second), would be calculated by dividing five cubic feet by twenty square feet which would give a velocity of about 0.25 feet per second. However, as the water would approach the constricted area defined by the fursto-conical rear end wall

74

in the opening

52

, the flow path would be constricted, and the velocity would increase to a much higher level.

The above explanations are given as background information so that the operating principals of the present invention can be better understood. With the foregoing being given as background information, attention is now directed toward

FIGS. 12 and 13

which show the drum

43

rear cone-shaped wall

74

and outlet opening

52

and the water jets

132

,

134

and

136

somewhat schematically.

First with reference to

FIG. 12

, in the preferred embodiment of the present invention, the two water jets

134

have an elongate, horizontally aligned discharge opening having dimension of about 8 inches wide by two inches deep. The two outside water jets

132

have horizontally aligned openings about four inches wide and two inches deep. The center lower jet

136

has a horizontal opening about four inches wide and two inches deep. With the volumetric flow rate being about 4.4 to 5.5. cubic feet per second, and with the total cross sectional area of orifices of the five discharge jets

134

-

136

being approximately fifty six square inches (which is about 0.4 Ft

2

), the velocity of the water flowing out of the jets on the average is about ten to fifteen feet per second. The jets

132

and

134

are oriented to discharge the water in a horizontal direction rearwardly, and the effect is to cause a relatively high velocity flow at the upper level of the water in the longitudinal central location. It can be seen in

FIG. 12

that the discharge end

142

of the conveyor

38

is located about four feet rearwardly of the discharge location of the jets

132

-

136

. As the wood pieces are falling off the conveyor

142

and entering into the water, these are engaged by the higher velocity water currents in the upper middle portion of the water and carried more rapidly toward the opening

52

. The side jets

132

also cause a rearward flow of the upper level of the water along the edges in a rearward direction at about the same velocity as (or slightly lower than) the velocity at the center location.

The lower middle jet

136

also adds to the action of the jets

132

and

134

, but adds an additional function. This jet

136

discharges rearwardly in a horizontal rearward direction (possibly with something of an upward slant) to engage some of the lower density material (e.g. water soaked wood) which may have a specific gravity very close to water or possibly even slightly greater than water. The water flow from the lower middle jet

136

tends to push such material rearwardly into the turbulent water at the upper level and helps to cause the discharge into the rear opening

52

.

To further appreciate the novel features of the present invention, there should be a discussion of the boundary layer effect, sheer forces, laminar and turbulent flow and eddy currents. If the diameter of the tube or other conduit carrying the fluid is sufficiently large and the velocity sufficiently low, then there may be laminar flow where the “layers” aligned in the direction of flow stay intact. However, as the velocity increases, then the sheer forces between the layers moving relative to one another due to the boundary layer effect becomes sufficiently great so that the flow becomes turbulent. When this occurs, the slower fluid closer to the side surface tends to move inwardly to the main flow, and fluid portions in a more central location move outwardly. This results in eddy currents and other turbulent motion of the fluid.

In many of the prior art separating systems where the particles or objects are separated by flotation in accordance with their specific gravity, this turbulence is considered harmful since the currents may tend to mix the lighter and heavier particles. However, in the present invention, the flow patterns developed enhance the separation process and also increase the production of the system.

To explain this further, attention is now directed to

FIG. 13

which is a longitudinal sectional view taken along a vertical center plane showing the flow over the lower rim portion

162

of the opening

52

, and also showing generally the flow patterns developed by the jets

132

,

134

, and

136

. For purposes of analysis and description, the body of water

163

can be considered as having three horizontal zones, namely an upper horizontal low density separation zone

174

extending between the upper water surface

176

and a level approximately one foot below the water at

178

, and possibly only one half of a foot or as great as one and a half feet, depending on the location and other factors. Then there is a lower high density separation zone

180

which extends between a lowermost portion

182

of the drum's interior surface up to a level

184

that is about a half foot or a foot above the lower level at

182

. Between the upper level

178

and the level

184

there is an intermediate zone

186

which could be termed the “quiescent zone”.

Then there shall also be considered the upper transversely extending longitudinally spaced zone sections in the upper zone

174

. With reference to

FIGS. 12 and 13

there is a front high velocity discharge zone section