The present invention relates to the application of semi-solid material to land, and more particularly to a vehicle for the application of bio-solids to farmland.
In the treatment of wastewater, either from industrial, agricultural or municipal sources, bio-solids or sludge are produced. One of the main problems in wastewater treatment is the environmentally safe and economic disposal of sludge.
One of the more favored methods of sludge disposal is by application onto agricultural land. In one such method, sludge is removed from a wastewater treatment plant in a highly liquid state and spread on to the land using a vehicle equipped with pumps that spray the sludge outward of the vehicle or, in some cases, inject the sludge into the soil using a toothed applicator. Similar types of vehicles are employed in the application of liquid animal manure. An example of such a vehicle is described in commonly owned US patent publication 2005/0061836.
One problem with this approach is that the sludge has a very high water content, which increases the shipping weight of the sludge. It is desirable to reduce the shipping weight by transporting de-watered sludge. One difficulty with this approach is that the sludge is no longer amenable to handling by pumping, so different handling and land application equipment is required.
A conventional manure spreader, for handling predominantly solid animal manure, comprises a moving chain in the bottom of the spreader and a pair of rotating spreader elements in the rear. The manure is broadcast rearwardly of the spreader and applied on top of the soil. Examples of such spreaders are provided in U.S. Pat. No. 3,123,363, U.S. Pat. No. 4,220,280, U.S. Pat. No. 5,199,638and U.S. Pat. No. 5,386,943. However, even when de-watered, the solids content of the sludge is lower than that of solid animal manure (i.e. there is still too much water) and would therefore not be suitable for application using a conventional manure spreader.
Accordingly, a different type of vehicle is required to apply de-watered bio-solids (or similar semi-solid materials) on agricultural land.
According to an aspect of the invention, there is provided a land application vehicle for semi-solid material. The vehicle includes a hopper having a hopper inlet and a hopper outlet, and a distributor having a transversely oriented length comprising a housing having a distributor inlet for receiving semi-solid material from the hopper, and at least one distributor outlet, a first distributor auger in the housing for transferring semi-solid material away from the distributor inlet and a second distributor auger in the housing for returning semi-solid material back towards the distributor inlet.
In one embodiment, the vehicle may comprise a generally V-shaped hopper. The semi-solid material may be transferred to the distributor via gravity or the hopper may contain an internal longitudinal auger at its bottom apex for transferring semi-solid material (such as bio-solids) from a front to a rear of the hopper. The distributor may be located at the rear and in fluid communication with the hopper outlet, which may also be located at the rear. The hopper outlet may be located at a bottom of the hopper and the distributor may be located at least partially beneath the hopper. The distributor inlet may be centrally positioned along the length of the housing and the first distributor auger may act to transfer the semi-solid materials away from the inlet towards the ends of the housing, while the second distributor auger acts to transfer the materials from the ends of the housing back towards the distributor inlet. The distributor inlet may be in fluid communication with both the first and second distributor augers.
The distributor may comprise a pair of transverse augers that may have continuous, oppositely oriented flights; in this embodiment, the augers are co-rotated (rotated in the same direction). In an alternative embodiment, the flights are oriented in the same direction and the augers are counter-rotated (rotated in opposite directions). The mutually opposed material transfer orientation of the augers creates recirculation to prevent packing of the semi-solid material within the distributor housing and the associated power loss and uneven distribution of semi-solid material that would result therefrom.
The first distributor auger may be positioned within the housing and configured for transferring the semi-solid materials towards the distributor outlet. In one embodiment, only the first distributor auger is so positioned and configured. The augers may or may not be intermeshing; intermeshing is advantageous in that it creates additional shear and aids in creating recirculation and self-cleaning of the augers. The first distributor auger may be located slightly below and rearward of the second distributor auger. The distributor outlet may comprise a plurality of discrete openings (e.g. five openings) provided in the bottom of the distributor housing evenly transversely spaced along the length of the distributor and proximal the first distributor auger in order that the semi-solid material can fall out on top of the ground beneath the distributor.
The speed of the augers may be adjusted to obtain distribution of the solids along the distributor, while at the same time creating enough shear to force the solids out through the distributor outlet. The speed adjustment may take into account the application rate and the quality of the semi-solid material (in terms of stickiness and water content). In one embodiment, each auger may be rotated at a different speed. The first distributor auger may rotate at a slower rate than that of the second distributor auger. The speed of the two augers may be adjusted in order to provide even distribution of semi-solid materials along the distributor while at the same time providing the desired amount of recirculation to prevent packing of the semi-solid material at the ends of the housing.
A soil incorporator may be optionally installed rearward of the applicator that comprises a plurality of earth working tools positioned and configured for covering the semi-solid material discharged onto the ground through the distributor outlets with earth. The earth working tools are designed to throw dirt over top of each strip of manure discharged from the distributor outlets. In this way, the strips are covered with soil in order to minimize odour and nutrient loss. The earth working tools may comprise a plurality of coulter wheels that may comprise at least one pair of coulter wheels, the pair comprising a first coulter wheel and a second coulter wheel. There may be a rear spacing between the first and second coulter wheels that is less than a front spacing. There may be a bottom spacing between the first and second coulter wheels that is less than a top spacing. This advantageously allows the incorporator to throw a sufficient amount of dirt to cover the semi-solid materials, without overly working the soil or creating too great of a power requirement for the vehicle towing implement.
It should be noted that dewatered bio-solids are semi-solid and have a water content of about 35-50%, giving them a thick consistency similar to cement. This is not analogous to the consistency of animal manure, which typically has a more solid consistency for cattle or poultry manure and a more liquid consistency for pig manure. Whereas pig manure is mostly liquid and readily pumpable, bio-solids are not; and, whereas cow and poultry manure are mostly solid and able to be handled using conveyors, conventional broadcast spreader means, etc., bio-solids are not amenable to this either. A truly new land application vehicle and handling system is therefore needed and provided by the present invention. Other examples of semi-solid materials that could benefit from such a vehicle and system include de-watered vegetable processing waste or sludge produced therefrom, drilling mud or debris removed from the drilling of oil or water wells, pulp and paper waste, and the like.
The vehicle may include some or all of the following desirable or advantageous features. The vehicle may allow for either conventional application on top of the soil or incorporation into the soil to reduce the odour and loss of desirable nutrient content through evaporation. The vehicle may be suitable to be pulled by either a truck, for highway transport, or a farm tractor, for application of the bio-solids to the field. The vehicle may be easy to fill, for example through the top of the vehicle, be easy to clean, and not be prone to plugging or sticking of any moving parts. The vehicle may be suitable for use as part of an integrated bio-solids handling system that includes means for loading the vehicle.
According to another aspect of the invention, a new type of loading apparatus is provided in order to facilitate loading of the land application vehicle. The loading apparatus includes an angled elevating chute and a chamber. The elevating chute has a loader chute inlet and a loader chute outlet and contains at least one elevating auger for transferring the semi-solid material up the chute to the loader chute outlet. The chamber is in fluid communication with the loader chute inlet, and has a main portion and a receiving portion. The receiving portion has a floor and a loading wall. The receiving portion is movable between a receiving position wherein the loading wall has a first lift-over height to facilitate loading of the chamber with semi-solid material, and an emptying position wherein the loading wall has a second, relatively higher lift-over height than in the receiving position.
In one embodiment, the chamber may be equipped with a lowerable side that comprises at least an outwardly pivoting portion. The chamber may be equipped with telescoping end plates connected to the lowerable side that together form a receiving chute when pivoted outwardly. In the receiving position, the floor may be at a first angle to horizontal and, in the emptying position, the floor may be at a second angle greater than the first angle. This facilitates loading of the chamber using a dump truck or similar vehicle, since these vehicles typically are not capable of delivering their payloads into a chamber with a high lift-over height. In the emptying position, the loading wall may be oriented to direct semi-solid material generally towards the loader chute inlet.
According to yet another aspect of the invention, the loading apparatus is provided in conjunction with the land application vehicle as part of a semi-solid material handling and land application system. In such a system, the loader chute outlet of the loading apparatus may be positioned relative to a top hopper inlet of the land application vehicle in order to discharge semi-solid material into the land application vehicle.
According to still another aspect of the invention, there is provided a method of operating a land application vehicle having a distributor, which has a distributor inlet and at least one distributor outlet for semi-solid material, comprising: feeding the distributor inlet with a flow of the semi-solid material; transferring semi-solid material away from the distributor inlet towards the at least one distributor outlet; and returning the semi-solid material back towards the distributor inlet.
The present invention will now be described by way of example only with reference to the attached drawings, in which:
Reference is made to
The vehicle 10 is used to apply the bio-solids 12 to land and may thus be referred to as a land application vehicle 10. The land application vehicle 10 includes a hopper 14, a longitudinal auger 16 positioned within the hopper 14, a distributor 18, and an optional incorporator 20.
The vehicle 10 has a front 22 and a rear 24. The hopper 14 receives and holds bio-solids 12 to be applied to suitable land, such as agricultural land. The hopper 14 has a hopper inlet 26 for receiving bio-solids that comprises an open top of the hopper 14. The hopper inlet 26 may alternatively be an inlet defined in a closed top to the hopper 14. The hopper 14 has a hopper outlet 28, concealed in
Although a frame is normally provided beneath the hopper 14, in some embodiments the hopper 14 may act as frame of the vehicle 10 and as such, the other components, such as vehicle wheels shown at 29, the distributor 18 and the incorporator 20 may be connected to the hopper 14, at least indirectly.
The longitudinal auger 16 may be any suitable type of auger, such as, for example, a continuous helical screw auger. The longitudinal auger 16 is positioned at the bottom of the hopper 14 and is configured to convey the bio-solid material 12 toward the hopper outlet 28, which is at the rear 24 of the hopper 14.
The bio-solid material 12 is discharged from the hopper outlet 28 and into the distributor 18, which is positioned at the rear 24 of the hopper 14. Referring to
The first distributor auger 32 has a shaft 44 and a flight 46. The flight 46 may include a first flight portion 46a that is provided with a selected orientation and a second flight portion 46b that is provided with a selected orientation that is opposed to the first flight orientation. Referring to
The distributor outlets 42 are located along the bottom 38 of the housing 30 proximal to and beneath the first auger 32. The orientation of the flight 46 and the direction of rotation of the first distributor auger drive system 48 may be selected so that the first distributor auger 32 is configured to convey bio-solid material 12 (
The second distributor auger 34 has a shaft 54 and a flight 56. The flight 56 may include a first flight portion 56a that is provided with a selected orientation that is opposed to the orientation of the first flight portion 46a of the first distributor auger 32, and a second flight portion 56b that is provided with a selected orientation that is opposed to the orientation of the second flight portion 46b of the first distributor auger 32. The flight 56 may thus have the opposite orientation to the flight 46 on the first distributor auger 32. The second distributor auger 32 may be driven by a second distributor auger drive system 58. A guard 63 is shown in
The second distributor auger 34 is positioned above the first auger 32 and forward of the distributor outlets 42. The orientation of the flight 56 and the direction of rotation of the second distributor auger drive system 48 may be selected so that the second distributor auger 34 is configured to convey bio-solid material 12 (
Referring specifically to
In an alternative embodiment (not shown), a single drive system may be provided for both the first and second distributor augers 32, 34. The augers may be geared to one another with a single gear ratio or several selectable gear ratios. This obviates the need for multiple drive motors and allows the distributor augers 32, 34 to rotate at the same speed or different relative speeds.
Multiple parameters relating to the release of bio-solids 12 from the distributor 18 can be at least somewhat independently controlled by providing variable speed capability for at least one of, preferably both of, the first and second distributor augers 32 and 34. In this manner, the overall application rate or flow rate of bio-solids 12 from the distributor 18 can be controlled independently of the distribution of bio-solids 12 across the width of the distributor as they leave through the distributor outlets 42. For example, the speeds of the first and/or second distributor augers 32 and 34 may be selected to achieve a selected overall flow rate of bio-solids 12 from the distributor outlets 42, while maintaining a generally even distribution of bio-solids 12 from the five distributor outlets 42.
As another example, the speeds of the first and/or second distributor augers 32 and 34 can be controlled to provide a selected overall flow rate of bio-solids 12 leaving the distributor outlets 42 while generating a selected amount of shear on the bio-solids 12 to urge them through the distributor outlets 42.
As another example, providing variable speed capability to the first and/or second distributor augers 32 and 34 permits the distributor 18 to be adjusted for the particular physical properties of a particular load of bio-solid material 12 (
As another example, the variable speed capability for the first and/or second distributor augers 32 and 34 permits the operator to control the distribution of bio-solids 12 leaving the distributor outlets 42, while generating sufficient shear in the bio-solids to urge them through the distributor outlets 42.
It is optionally possible that only one of the distributor augers 32 and 34 be provided with variable speed capability. This would still be advantageous in several respects. For example, variable speed capability on one of the first or second distributor augers 32 or 34 may be used to control the discharge rate of bio-solids 12 from the distributor 18.
It is also optionally possible for neither of the distributor augers 32 and 34 to have variable speed capability.
It is also optionally possible to have the second distributor auger 34 be operated at a faster rotational speed than the first distributor auger 32.
It is also possible for the first and second distributor augers 32, 34 to be operated at the same speed and for that speed to be fixed or variable. This is particularly advantageous when the augers are intermeshing.
As shown in
The first distributor auger 32 may be positioned rearward of and below the level of the second distributor auger 34. The rotation of the first distributor auger 34 is such that it pushes the bio-solids 12 downwardly and out through the distributor outlets 42 against the frictional resistance of the distributor housing 30, and pushes upwards on the bio-solids 12 where it interacts with the second distributor auger 34. The distributor outlets 42 may be positioned generally under and slightly behind the first distributor auger 32 so that force of the first distributor auger 32 pushes the bio-solids 12 through the distributor outlets 42. It is alternatively possible, however, for the distributor outlets 42 to be positioned elsewhere in the distributor housing 30. For example, the distributor outlets 42 may be positioned in the end walls of the housing, shown at 64 and 66 in
The second distributor auger 34 may co-rotate with the first distributor auger 32 and may thus rotate downwards where it interacts with the first distributor auger 32.
In an alternative embodiment that is not shown, it would be possible to provide the first and second distributor augers 32 and 34 with identical flights instead of oppositely oriented flights, and to counter-rotate the first and second distributor augers 32 and 34.
The distributor 18 is shown in the figures as being generally oriented transversely. It is alternatively possible for the distributor 18 to have some other orientation, such as an orientation that is angled between the transverse and longitudinal directions.
Referring to
Each pair 74 of coulter wheels 72 may be mounted to an individual sub-frame 80, which may be resiliently mounted to the frame 68 by means of leaf springs 82. The frame 68 may be movable between a raised, ie. non-operating, position (
Referring to
A land application vehicle having a distributor that has a distributor inlet and at least one distributor outlet, in accordance with an embodiment of the invention, may be operated by the following method: feeding the distributor inlet with a flow of bio-solids, transferring bio-solids away from the distributor inlet towards the distributor outlet, and returning bio-solids back towards the distributor inlet. The steps of transferring bio-solids away from the distributor inlet and returning bio-solids back towards the distributor inlet may be accomplished using first and second distributor augers, respectively. The first distributor auger rotates at a first distributor auger speed and the second distributor auger rotates at a second distributor auger speed. The method may further comprise adjusting at least one of the first and second distributor auger speeds based on the physical properties of the bio-solids, and/or to control the flow rate of bio-solids from the one or more distributor outlets, and/or to control the distribution of bio-solids across the one or more distributor outlets, and/or to control other parameters, such as shear. Optionally, both of the distributor auger speeds are adjusted based on the physical properties of the bio-solids, and/or to control one or more performance parameters of the distributor, such as the flow rate of bio-solids from the one or more distributor outlets or the distribution of bio-solids leaving the distributor outlets.
Reference is made to
The chamber 98 is in fluid communication with the loader chute inlet 100. The chamber 98 includes a main portion 105 and a receiving portion 106. The receiving portion 106 has a floor 108, a pair of side walls 109 and a loading wall 110, and is movable (for example, by pivoting) between a receiving position shown in
In the emptying position, (
The ends of the valley 112 are closed by the side walls 109 of the receiving portion 106 and by side walls of the main portion 105, which are shown at 118. When the receiving portion 106 moves between the receiving and emptying positions, the side walls 109 may slide along the side walls 118 inside of (i.e. adjacent the inner faces of) the side walls 118.
The elevating augers 104 may be similarly flighted and may co-rotate, or alternatively, they may be oppositely flighted and may counter-rotate. The elevating chute 96 may be divided by a divider 120 into two chute portions 96a and 96b, each of which contains an elevating auger 104.
The loader 90 may be movable on wheels 122 into an emptying position wherein the loader chute outlet 102 is positioned above the hopper inlet 26 at the top of hopper 14 of the land application vehicle 10.
The loader 90 may itself be loaded with bio-solids 12 by any suitable means. For example a dump truck (not shown) may be provided as part of the semi-solid material handling and land application system 92.
While the above description constitutes a plurality of embodiments of the present invention, it will be appreciated that the present invention is susceptible to further modification and change without departing from the fair meaning of the accompanying claims.
This application claims the benefit of U.S. patent application 61/083,903, filed on Jul. 25, 2008, which is incorporated herein by reference.
Number | Date | Country | |
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61083903 | Jul 2008 | US |