screw conveyor

Abstract

A screw conveyor for a drying apparatus (1) or a fermentation system is disclosed. The screw conveyor comprises a screw element (11) having a longitudinal axis (x) and comprising a primary screw (12) and a secondary screw (13) mounted on the primary screw and rotatable about the longitudinal axis relative to the primary screw; a set of elongate members (20) spanning the primary screw and the secondary screw.

Description

Technical Field

[0001] The present invention relates to a screw conveyor, which is specifically, but not exclusively, used in drying equipment or fermentation systems. Background Technology

[0002] US 5,561,917 A describes a slurry dryer including a rotatable drum with a feed screw equipped with clamping fins attached to the inside of the drum. Initially, the screw feeds slurry into the drum through a slurry inlet. As the drum rotates, the feed screw and clamping fins simultaneously convey the slurry to be processed from the drum inlet to the drum outlet. The drum has a completely solid cylindrical outer wall.

[0003] Spiral dryers consisting of perforated drums are known, with a screw integrally attached to the inner surface of the perforated drum.

[0004] KR 200280671 discloses a dryer apparatus for drying various types of waste. Waste is introduced into a drying chamber through an inlet hopper and a waste crusher. Multiple screw conveyors move within the drying chamber, each screw conveyor including a screw element and a trough. The screw conveyors transport the dried waste as they move toward the outlet of the drying chamber. The dried waste is then conveyed to an incinerator. The screw conveyors have blades fixed between a first and second ring of the screw element. The blades, inclined at a predetermined angle relative to the longitudinal direction, are used for transporting and crushing the waste.

[0005] Because the blades are rigidly attached to the rings of the screw element, it is not feasible to change their position to accommodate different types of materials to be treated. These materials vary in properties, particularly in quality and quantity, thus requiring specific mixing times for drying and residence times in the conveyor to achieve the desired moisture content. Since the position of the screw conveyor blades is fixed between each ring of the screw element, it is not feasible to optimize the drying process for each specific type of material to be treated. Summary of the Invention

[0006] According to a first aspect of the invention, a screw conveyor is provided. The screw conveyor includes a helical element (or "helical blade assembly") having a longitudinal axis. The screw conveyor includes a main helix (or "first helical blade") and a secondary helix (or "second helical blade") mounted on the main helix and rotatable relative to the main helix about the longitudinal axis. The screw conveyor includes a set of elongated members spanning the main helix and the secondary helix.

[0007] Therefore, by rotating the secondary spiral relative to the first spiral, the tilt angle of the elongated member can be changed, thus allowing the spiral conveyor to adapt to different scenarios and different types of materials conveyed and / or processed therein.

[0008] The helical element can be configured such that the secondary helix can rotate relative to the first helix between a lower angle limit and an upper angle limit. The difference between the lower angle limit and the upper angle limit can be between 20° and 40°, preferably between 25° and 35°. The lower angle limit can be 0° and the upper angle limit can be between 20° and 40°. The lower angle limit can be between –10° and –20° and the upper angle limit can be between 10° and 20°.

[0009] The primary helix and the secondary helix may be interwoven. The primary helix and the secondary helix may be coaxial. The secondary helix may be adjacent to the primary helix. The turns of the primary helix and the secondary helix may be matched. The pitch of the primary helix and the secondary helix may be the same. The helical element may have multiple turns. The number of turns in the primary helix and the secondary helix may be the same as the number of turns in the helical element. For most of the length of the helical element (i.e., greater than 50%) or substantially all of the length of the helical element (i.e., greater than 90%), the number of turns in the primary helix and the secondary helix may be the same.

[0010] The elongated member may be off-axis (i.e., away from the longitudinal axis). The end of the elongated member may be located close to the outer periphery of the turns of the main helix and the secondary helix. At least one elongated member may have two ends, wherein a first end may be positioned on a first turn of the helical element and a second end may be positioned on a second turn facing the first turn.

[0011] The first end of the slender member can be hinged to the main helix or the secondary helix. Alternatively, the first end of the slender member can be attached to the main helix or the secondary helix via a cylindrical hinge. Or, the first end of the slender member can be attached to the main helix or the secondary helix via a universal joint.

[0012] The second end of the elongated member can be slidably attached to the main helix or the secondary helix. The elongated member can be arranged such that the second end can move freely in a direction parallel to the longitudinal axis.

[0013] The second end of the elongated member may be located in a sliding guide attached to the main helix or the secondary helix. The sliding guide may include a U-shaped member (or a C-shaped member) providing a slot, in which the second end of the elongated member is slidably disposed.

[0014] The first end of each elongated element is pivotable on a first turn of a turn selected from the main helix and the secondary helix, and the second end of the elongated element preferably slides in contact with a second turn selected from the turns of the secondary helix and the main coil helix, such that the position of the elongated element is modified in a controlled manner relative to the longitudinal axis of the helical element by tightening or loosening the secondary helix relative to the main helix.

[0015] The screw conveyor may further include a plurality of slots and a plurality of retaining pins disposed in the main screw and / or the secondary screw, each retaining pin passing through a corresponding slot. The slots and retaining pins are arranged to guide the secondary screw to rotate relative to the main screw about the longitudinal axis. The slots are preferably arc-shaped. The slots are preferably spaced at an angle around the screw, for example, at least one in each turn of the screw. The arc length of the slots may be between 20° and 40°, preferably between 25° and 35°.

[0016] The screw conveyor may further include a rod coupled (or “communicated”) with the secondary helix, which, upon rotation, causes the secondary helix to rotate about the longitudinal axis relative to the main helix. The rod preferably extends along the longitudinal axis. The screw conveyor may also include an actuator coupled to the rod for rotating the secondary helix relative to the main helix to a desired angular position and for immediately locking the secondary helix at the desired angular position. The actuator may include a hydraulic adjustment device.

[0017] The screw conveyor can be used in drying equipment that can process a variety of different substances, using a perforated tube with an integrated internal screw (“spiral”) to advance the substance to be processed from the inlet to the outlet of the outlet drying equipment.

[0018] The elongated member may be in the form of a rod or a strip. Preferably, the elongated member spans between the turns of the main helix and the adjacent facing turns of the secondary helix.

[0019] The material to be dried can be sludge. The sludge can be papermaking sludge. The sludge can be wastewater sludge.

[0020] The screw conveyor can be used in equipment not intended for drying. Therefore, the water content of the material conveyed and / or processed by the screw conveyor may not change or will remain substantially unchanged. For example, the material may be a fermentable substance, such as biomass, which can be used to provide food for human consumption or as a raw material for animal consumption (e.g., livestock or farm animals).

[0021] The helical element, elongated member, and other mechanical or moving parts of the screw conveyor may be made of stainless steel. Some parts, particularly those that contact, slide along, or move against another part, such as hinges, joints, or pivots, may be made of bronze. The main helix, the secondary helix, and / or the elongated member and / or hinges or joints may be sealed or coated with plastic.

[0022] According to a second aspect of the invention, a fermentation system (or "fermentation equipment" or "fermentation tank") is provided, comprising at least one screw conveyor, the at least one screw conveyor including the screw conveyor of the first aspect.

[0023] According to a third aspect of the invention, a drying apparatus is provided comprising at least one screw conveyor, said at least one screw conveyor comprising the screw conveyor of the first aspect.

[0024] According to a fourth aspect of the invention, a drying apparatus comprising a plurality of screw conveyors is provided, each screw conveyor comprising the screw conveyor described in the first aspect.

[0025] The drying apparatus may further include a support frame, a front end, a rear end, and a top wall. The drying apparatus may also include a hopper for receiving the material to be dried through an inlet in the top wall; and a rotary cylindrical valve downstream of the hopper, the rotary cylindrical valve being located near the front end. The screw conveyors are rotatably supported on the front and rear ends, and the rear end has a sprocket and one or more drives for advancing the material to be dried to an outlet of the apparatus. The drying apparatus may also include a heated air system adapted to supply heated air to the plurality of screw conveyors for dehydrating the material to be dried, wherein the drying apparatus is arranged to allow humid air to escape through openings in the top wall.

[0026] The screw conveyors may be arranged in a row above each other, wherein the first lower screw conveyor includes a screw element arranged in a trough, and the second intermediate screw conveyor and the third upper screw conveyor have their main helices rigidly connected to corresponding screw elements of a perforated tube, the perforated tube surrounding the screw element and rotating integrally therewith.

[0027] The screw conveyors in the column are housed in one or more shells with openings adapted to convey the heated air, wherein the heated air system includes at least one supply pipe, a secondary pipe, and at least one conveying box, the at least one conveying box being supported by the support frame and adapted to supply heated air from the one or more shells directly to the intermediate screw conveyor and the upper screw conveyor through the openings.

[0028] The one or more shells may have the same facing protrusion to form a prismatic shell, and the perforated tube has longitudinal fins that project outward and are adapted to interact with the facing protrusion to retain the heated air in the prismatic shell before it leaves as moist air through the opening.

[0029] The one or more drives may include gear motors mounted on the rear end and connected to the sprockets by means of a flexible transmission member. The one or more drives may include multiple gear motors, each arranged to drive a corresponding sprocket. The drying equipment may also include multiple hygrometers mounted close to the screw conveyor, for example, mounted on the one or more housings.

[0030] According to a fifth aspect of the invention, a system is provided for use with the drying apparatus of the third or fourth aspect, the system comprising: a dehydrated waste incinerator; a first fan for supplying air from the outside; a heat exchanger for supplying heated air to the drying apparatus on one side downstream of the dehydrated waste incinerator and on the other side downstream of the first fan; a granulator located downstream of the outlet of the drying apparatus for the material to be dried and upstream of the incinerator; a condenser for using tap water to exit the humid air of the drying apparatus, the tap water entering through a branch, a first pipe exiting the condenser for wastewater, and a second pipe for returning water to the tap water; a second fan located downstream of the condenser for recirculating smoke within the drying apparatus; and a smoke purifier adapted to receive cooling air from the condenser and smoke from the heat exchanger as an alternative to recirculation, wherein the pipe exiting the purifier is for wastewater.

[0031] The drying equipment can be operated with a variable flow rate and a constant rotation speed. The drying equipment can also be operated with a fixed flow rate and a variable rotation speed. The drying equipment can be operated with an automatically variable degree of mixing at a constant flow rate. The drying equipment may have independent chambers with variable humidity. The drying equipment can be operated to reverse the flow, which allows for a reduction in its overall size. The drying equipment can be configured with cyclone, vertical, and horizontal warm airflows. The drying equipment may have a hot airflow with an adjustable flow rate and a forced path to control the descent speed of the product to be dried. Depending on the substance to be treated, the drying equipment can be operated to provide strong or extremely gentle mixing.

[0032] The drying device may employ a spiral that cooperates with a perforated support tube attached to the inner wall of the support tube. Multiple holes, up to and including micrometer-sized holes, exist along most of the length of the tube, and their size prevents leakage of the material to be dried. Secondary spirals flank the main spiral, which can be tightened or loosened onto the main spiral and controlled from the outside of the device. An elongated element is mounted between the main spiral rings and the second spiral rings facing each other; the inclination of the elongated element relative to the longitudinal axis of the screw is adjustable by the relative rotation of the secondary spirals relative to the main spiral. The elongated element may be in the form of straight blades or other blades configured in a similar manner.

[0033] The drying equipment can improve performance by adjusting the contact time between air and the material to be dried, by regulating the mixing of screw rotation speeds, by adjusting the angle of the elongated element that can tilt between the main and secondary screws, and by selecting the direction and path of air delivery. The end result is a drying equipment that can increase or maximize the achievable percentage of drying yield with equal energy input, or reduce or minimize the amount of energy input while achieving the same percentage of drying. Energy savings between 20% and 40% can be achieved, depending on the properties of the material to be dried.

[0034] The equipment can be used to dry clean water sludge and industrial sludge, but it can also be applied to the agricultural and food industry to dry grains, pasta, and semi-processed tubers for subsequent production of edible powders, dried fruits, etc.

[0035] According to a sixth aspect of the invention, a drying apparatus is provided. The drying apparatus includes a support frame, a front end, a rear end, and a top wall; a hopper for receiving a material to be dried through an inlet in the top wall; and a rotatable cylindrical valve downstream of the hopper, the rotatable cylindrical valve being adjacent to the front end. The drying apparatus includes a plurality of screw conveyors supported on the front and rear ends and equipped with a toothed crown and a drive mechanism on the rear end for moving the material to be dried through the drying apparatus to an outlet of the apparatus. Each screw conveyor includes a helical element and at least one elongated member having two ends, the helical element having a longitudinal axis x and being equipped with a plurality of turns, a first end of the two ends being positioned on a first turn of the helical element and a second end being positioned on a second turn facing the first turn. The drying apparatus includes a heated air system adapted to supply heated air to the plurality of lower screw conveyors, intermediate screw conveyors, and upper screw conveyors for dehydrating the material to be dried, the humid air escaping from an opening in the top wall. Each helical element of the screw conveyor is formed by a primary coil and a secondary coil, the primary coil and the secondary coil having a number of turns that match each other. The first end of each elongated element pivots on a first turn selected from the turns of the primary coil and the turns of the secondary coil, and the second end of the elongated element slides into contact with a second turn selected from the turns of the primary coil and the turns of the secondary coil, such that the position of the elongated element is modified in a controlled manner relative to the longitudinal axis x of the coil element by tightening or loosening the secondary coil relative to the primary coil.

[0036] The mating turns may be provided with corresponding slots and retaining pins through them, so that the secondary coil can be tightened and loosened on the primary coil, one end of the secondary coil being connected to the secondary coil shaft and adapted to be controlled from the outside of the front.

[0037] The first end of the elongated element can be pivoted on the turn of the main coil using a cylindrical hinge, and the second end of the elongated element can be inserted into a sliding guide rail disposed in the turn of the secondary coil.

[0038] The secondary coil shaft may be equipped with a lever adapted for manual rotation, and the lever is locked once the rotation arc of the lever has covered the desired position corresponding to the elongated element.

[0039] The secondary coil shaft can be configured to be connected to a hydraulic adjustment device, which is activated and locked once the rotational arc corresponding to the desired position of the elongated element has been covered.

[0040] The screw conveyors may be arranged in at least a row above each other. The lower screw conveyor is a screw element arranged inside the trough. The intermediate and upper screw conveyors have screw elements whose main coils are rigidly connected to a perforated tube, which surrounds and is rotatable integrally with the screw element. The row of screw conveyors is housed in a shell with openings adapted to supply the heated air. The heated air system includes at least one supply pipe, a secondary pipe, and at least one delivery box. The at least one delivery box is supported by the support frame and adapted to supply heated air from within the shell directly to the intermediate and upper screw conveyors through the openings provided on the shell. The shell may have identical facing protrusions to be configured together with the prismatic shell, and the perforated tube has longitudinal fins that project outward and are adapted to cooperate with the facing protrusions to retain the heated air in the prismatic shell before it leaves the drying equipment as humid air through the openings.

[0041] The device for driving the screw conveyor may include a gear motor, preferably a single-gear motor, which is mounted on the rear head and simultaneously connected to the tooth crown of the screw conveyor by means of a flexible transmission member.

[0042] The means for driving the screw conveyors may include a gear motor for each screw conveyor.

[0043] Multiple hygrometers can be mounted on the housing near the screw conveyor.

[0044] According to a seventh aspect of the invention, an apparatus for using the drying equipment is provided, the apparatus comprising: a dehydrated waste incinerator; a first fan for supplying air from the outside; a heat exchanger adapted to supply heated air to the drying equipment on one side downstream of the dehydrated waste incinerator and on the other side of the first fan; a pellet mill located downstream of the outlet of the drying equipment for the material to be dried and upstream of the incinerator; a condenser for using tap water (WR) to exit the humid air from the drying equipment, the tap water entering through a branch, a first pipe exiting the condenser for wastewater, and a second pipe for returning water to the tap water; a second fan located downstream of the condenser for recirculating the smoke in the drying equipment; and a smoke purifier adapted to receive cooling air from the condenser and smoke from the heat exchanger as an alternative to recirculation, the pipe exiting the purifier for wastewater.

[0045] The equipment can be used to dry food, waste, or other materials.

[0046] According to an eighth aspect of the present invention, a system for treating dewatered sludge is provided.

[0047] A screw conveyor device may be provided in which the material to be dried is fed at one end and the dehydrated material is discharged at the other end. An airflow or other type of heat transfer is being performed in a counter-current manner. The speed of the screw, as well as its diameter and pitch, can be used to determine the output rate (e.g., output per hour) and the degree of dryness of the processed material. Attached Figure Description

[0048] Some embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

[0049] Figure 1 This is a perspective view of the drying equipment;

[0050] Figure 2 yes Figure 1 A front view of the rear end of the drying equipment shown;

[0051] Figure 3 yes Figure 1 The drying equipment shown is a perspective view without the support frame;

[0052] Figure 4 yes Figure 1 A perspective view of the interior of the drying equipment shown;

[0053] Figure 5 yes Figure 3 A schematic cross-sectional view of the drying equipment shown;

[0054] Figure 6 yes Figure 3 A schematic longitudinal section view of the drying equipment shown;

[0055] Figure 7 yes Figure 6 A schematic perspective view of the screw conveyor casing of the drying equipment shown;

[0056] Figure 8 yes Figure 7 An exploded perspective view of the shell shown;

[0057] Figure 9 yes Figure 4 A schematic perspective view of the screw conveyor shown;

[0058] Figure 10 yes Figure 3 A partially enlarged perspective view of the end of the screw conveyor shown;

[0059] Figure 11A yes Figure 9 A schematic perspective view of the screw element of the screw conveyor as seen from the left front position;

[0060] Figure 11B yes Figure 9A schematic perspective view of the screw element of the screw conveyor as seen from the front right position;

[0061] Figure 12A yes Figure 11A A first enlarged detail view of the end of the spiral element shown;

[0062] Figure 12B yes Figure 11B A first enlarged detail view of the end of the spiral element shown;

[0063] Figure 13A yes Figure 11A The second enlarged detail of the spiral element shown, wherein the elongated element is in the first position;

[0064] Figure 13B yes Figure 11B A second enlarged detail of the spiral element shown;

[0065] Figure 13C yes Figure 11A The third enlarged detail of the spiral element shown, in which the elongated element is in the second position;

[0066] Figure 13D yes Figure 11A An exploded and enlarged detailed view of the end of the spiral element shown;

[0067] Figure 14A yes Figure 11A A top-view enlarged detail of the spiral element shown;

[0068] Figure 14B This is a top-view magnified detail of the spiral element, in which the slender element is in different positions;

[0069] Figure 15 Enlarged top views of the spiral element in the first, second, and third positions are shown;

[0070] Figure 16 It is a partial perspective view of the front end of a modified drying device with a drive.

[0071] Figure 17 It is a partial perspective view of the rear end of a drying device with a variable actuator; and

[0072] Figure 18 This is a schematic diagram of a system using drying equipment. Detailed Implementation

[0073] refer to Figure 1 The drying device 1 is shown.

[0074] The drying device 1 includes a support frame 2, a front end 3 and a rear end 4, a top wall 43, and a hopper 5 for receiving the material to be dried through an opening in the top wall 43 near the front end 3. A rotating cylinder 9 is disposed below the hopper 5, i.e., downstream of the hopper 5. The top wall 43 has an opening 40 to allow humid air to escape from the interior of the drying device 1.

[0075] Also refer to Figure 2 , Figure 3 and Figure 4 The rear end 4 of the drying equipment 1 has a set of drive units (or "drivers") for multiple screw conveyors 90, 91, 92 rotatably supported on the front end 3 and the rear end 4. Corresponding sprockets 6 are mounted at the ends of the screw conveyors 90, 91, 92 (at...). Figure 4 (Best shown in the diagram). Screw conveyors 90, 91, and 92 are arranged in two columns. In this case, there are three screw conveyors in each column: a lower screw conveyor 90, a middle screw conveyor 91, and an upper screw conveyor 92. The middle screw conveyor 92 is inserted between the lower screw conveyor 90 and the upper screw conveyor 92. However, there may be more screw conveyors. For example, there may be more columns, and / or more screw conveyors in each column.

[0076] The sprocket 6 is connected to a drive unit in the form of a geared motor 8 via a flexible transmission member 7 in the form of a chain, and is arranged to simultaneously drive screw conveyors 90, 91, and 92. The motor 8 drives the screw conveyors 90, 91, and 92 to cause the material to be dried to flow to the outlet (not shown) of the drying equipment 1.

[0077] refer to Figure 3 , Figure 4 , Figure 5 and Figure 6 The lower screw conveyor 90 includes a screw element 11 (or "screw blade assembly") (preferably having a center rod) and a trough 110.

[0078] Also refer to Figure 11A and 11BThe helical element 11, having a longitudinal axis x, is formed by a main helix 12 (also referred to herein as a "first helix," "first coil," or "first screw") having mutually mating rings 12n and 13n (also referred to herein as "helical blades") and a secondary helix 13 (also referred to herein as a "second helix," "second coil," or "second screw"). The helical element 11 may be formed of stainless steel or other suitable materials. The helical element 11 may be coated, for example, with plastic. The main helix 12 has a main ring 12n, and the secondary helix 13 has a secondary ring 13n, where n represents the ring number (e.g., 1, 2, ..., N). The ring 13n of the secondary helix 13 is adapted to maintain contact with the ring 12n of the main helix 12. In other words, the ring 13n of the secondary helix 13 is adjacent to the ring 12n of the main helix 12.

[0079] The main helix 12 and the second helix 13 are intertwined. The main helix 12 and the second helix 13 are coaxial.

[0080] Also refer to Figure 12A Matching rings 12n and 13n are provided with corresponding slots 14. Retaining pins 15 passing through the corresponding slots 14 of rings 12n and 13n are held (or "secured") against the main screw 12 by means of retaining rings 16. Thus, the secondary screw 13 can be tightened and loosened on the main screw 12 within the arc allowed by the slots 14 and retaining pins 15.

[0081] As will be explained in more detail below, the secondary spiral 13 has a distal end connected to a secondary spiral rod 17, which can be controlled from the outside of the front end 3 of the drying device 1. Figure 12A The rigid connection between rod 17 and secondary helix 13 is schematically shown in the diagram.

[0082] The main screw 12 in each screw conveyor 90, 91, and 92 is driven to rotate by a gear motor 8 via a sprocket 6 and a flexible transmission component 7.

[0083] refer to Figure 9 The difference between the intermediate screw conveyor 91 and the upper screw conveyor 92 and the lower screw conveyor 90 is that they are enclosed in tube 18 (i.e., they are “inserted”). These conveyors 91, 92 do not have a central rod and the main screw 12 is engaged to the perforated tube 18 surrounding the screw element 11.

[0084] Also refer to Figure 13A The joint 19 between the main spiral 12 and the perforated tube 18 is achieved, for example, by welding a rod (or "plate").

[0085] The material to be dried (not shown) falls from the opening of the receiving hopper 5 into the upper and lower screw conveyors 92 and 90, and simultaneously passes through the middle screw conveyor 91 via the end opening 10 at the end of the upper screw conveyor 92.

[0086] refer to Figure 14A Each ring 12n of the main spiral 12 is connected to the ring 13n of the secondary spiral 13 by means of at least one elongated element 20.

[0087] In this example, each pair of rings 12n, 13n is joined by three elongated elements 20 (or “elongated members”) spaced 120° apart around each ring 12n, 13n. The elongated elements 20 may be formed of stainless steel or other suitable materials. The elongated elements 20 may be coated, for example, with plastic. The elongated elements 20 are in the form of blades. Each elongated element 20 may have a shape different from that of a blade. For example, the elongated elements 20 may be curved, twisted, or of a different shape. Each elongated element 20 has a first end 21 and a second end 22. The first end 21 is positioned on the ring 12n of the main helix 12, and the second end 22 is positioned on the second consecutive ring 13n of the secondary helix 13.

[0088] The first end 21 of the elongated element 20 pivots on the first ring 12n of the main helix 12, and the second end 22 of the elongated element 20 slides in contact with the second ring 13n of the secondary helix 13. Due to this configuration, the position of each elongated element 20 relative to the longitudinal axis x of the helical element 11 can be modified in a controlled manner.

[0089] The first end 21 and the second end 22 of each element 20 may otherwise be attached, restricted or attached to the screws 12, 13.

[0090] The first end 21 of the elongated element 20 is pivotable by means of a cylindrical hinge 23 on the ring 12n of the main helix 12, and the second end 22 of the elongated element 20 is insertable into a sliding guide 24 disposed on the facing ring 13n of the secondary helix 13. The guide 24 is in the form of a "U"-shaped (or "C"-shaped) member providing a slot (or "fork") in which the second end 22 of the elongated element 20 is located and slidably moved. The second end 22 may include a roller to facilitate movement of the second end 22 of the member 20. The elongated element 20 may be provided with some other arrangement (e.g., a slider or piston) that allows movement in a direction parallel to the longitudinal axis. Alternatively, the cylindrical hinge 23 may be disposed on the ring 13n of the secondary helix 13, and the sliding guide 24 may be disposed on the facing ring 12n of the main helix 12.

[0091] The rotation allowed by the slot 14 and retaining pin 15 simultaneously changes the spatial position of all the elongated elements 20 between each pair of rings 12n of the main helix 12 and each pair of rings 13n of the secondary helix 13.

[0092] Special Reference Figure 12A The tightening and loosening of the secondary screw 13 relative to the main screw 12 can be performed manually with the help of the secondary screw rod 17.

[0093] Also refer to Figure 10 The rod 17 of the secondary screw component 13 is provided with a lever 25, which is integral with the rod 17 and can be manually rotated. The lever 25 has a guide sleeve at its free end through which a pointer 27 passes. The pointer 27 is preferably a spring-loaded rod, the tip 28 of which can be positioned within a seat made of a nut among a plurality of nuts 29 welded to the front end 30 of the screw conveyor 90. Figure 6 ).

[0094] With the aid of lever 25, the desired position of the elongated element 20 can be achieved by rotating the desired circumferential arc and positioning it by pointer 27 in the cavity of nut 29 corresponding to the desired rotation of secondary helix 13 relative to main helix 12.

[0095] refer to Figure 16 As an alternative to manual operation of the secondary screw 17, once the desired rotation angle corresponding to the elongated element 20 has been reached, the secondary screw 17 can be configured at its free end to be connected to a hydraulic adjustment device 26 for actuation and locking. The hydraulic device 26 is connected to separate actuators that are applied to the corresponding rods 17 of the screw 13 of the screw conveyor.

[0096] Refer again Figure 1 The drying equipment 1 includes a heated air system 31 adapted to supply heated air to a plurality of screw conveyors for dehydration of the material to be dried and for treating the humid air at the outlet. The air supply section of the system 31 includes a main supply pipe 32 that branches off from secondary pipes 33 to reach a housing 34 surrounding the rows of screw conveyors 90, 91, and 92.

[0097] Refer again Figure 7 and Figure 8 The casing 34 of the screw conveyor is shown in more detail. A conveying box 35 is disposed between the secondary pipe 33 and the casing 34 to distribute heated air within the casing 34. For this purpose, the casing 34 has an opening 36 that allows heated air to be conveyed into the casing 34.

[0098] Also refer to Figure 6 The heated air supply system 31, comprising the main supply pipe 32, secondary pipes 33, shell 34, and conveyor box 35, is supported by the support frame 2 and is adapted to directly supply heated air from within the shell 34 to the intermediate screw conveyor 91 and the upper screw conveyor 92 through an opening 36 provided on the shell 34. The opening 36 is positioned below the intermediate screw conveyor 91 so that the heated air does not interfere with the advance of the material to be dried, which is currently being dehydrated, present in the lower screw conveyor 90. The pressure of the advancing heated air does not affect the intermediate conveyor 91 and the upper conveyor 92 because the size of the holes in the perforated pipe 18 surrounding them prevents leakage of the material to be dried.

[0099] Still referencing Figure 6 The shell 34 has the same facing protrusion 37 to jointly construct the prismatic shell 38, and the perforated tube 18 has outwardly projecting longitudinal fins 39, which are adapted to mate with the facing protrusion 37 to allow heated air to pass through the opening 40 as humid air. Figure 1 , Figure 2 and Figure 3 The heated air is retained in the prismatic housing 38 before leaving the drying equipment.

[0100] As described above, the drive unit of the screw conveyor includes a single gear motor 8 that is mounted on the rear end 4 of the drying equipment 1 and simultaneously connected to the sprockets 6 of the screw conveyors 90, 91, and 92 via a flexible transmission member 7.

[0101] refer to Figure 17 The drive unit for screw conveyors 90, 91, and 92 may include a corresponding gear motor 41 for each conveyor.

[0102] Multiple hygrometers 42 are installed close to the screw conveyors 90, 91, and 92. The hygrometers 42 allow for the assessment of moisture content in various parts of the screw conveyors. These hygrometers enable the determination of the positions of the elongated elements 20, which are determined by their inclination relative to the longitudinal axis x of the screw element 11 of each screw conveyor. This helps ensure the persistence and mixing degree of the material to be dried in the various parts of the screw conveyor.

[0103] Figure 15 The diagram shows three different tilt angles of the elongated element 20 relative to the longitudinal axis x: 0°, –15°, and +15°. Other different tilt angles are also possible within the range of –15° and +15°. Tilt angles exceeding –15° and +15° are also possible.

[0104] If Q is the material flow rate when the elongated element 20 is not running at a given speed using the helical element 11, the material flow rate can be controllably reduced by leveling the elongated element 20 (in other words, by changing the tilt angle of the elongated element 20). If the elongated element 20 is used and aligned with the helical element 11 (i.e., parallel to the longitudinal axis), the flow rate is Q / 10. The rate can be increased or decreased. For example, if the angle of the elongated element 20 is –15°, so that the elongated element 20 is perpendicular to the surface of the helical element 11, the flow rate decreases to Q / 20. Conversely, if the angle of the elongated element 20 is +15°, the flow rate increases to Q / 5. The value of the flow rate may depend on the composition and / or properties of the material. For example, a denser material (e.g., a drier material) flows faster than the same less dense material (e.g., a wetter material), i.e., has a higher flow rate.

[0105] refer to Figure 18 This diagram illustrates a wastewater treatment system employing the drying apparatus 1 described herein. The drying apparatus is designated 1. A heat exchanger 50 is located downstream of the waste incinerator 51 on one side and downstream of the first fan 52 on the other side. The heat exchanger 50 is located upstream of the drying apparatus 1. A condenser exiting the drying apparatus 1 is designated 53, a second fan is designated 54, and a flue gas purifier is designated 55. WR represents a water network flowing through the condenser 53 via a first branch WRe and exiting the condenser via a second branch WRu. Condensate WC1 combines with condensate WC2 from the flue gas purifier 55 to form wastewater WW. Gas circulation includes inflow air Ai supplied from the outside via the first fan 52, which, when heated by the incinerator 51, enters the drying apparatus 1 as Ac.

[0106] Dry sludge is introduced along arrow F, and the dewatered sludge exits the screw conveyor and is transported to waste incinerator 51, which is also fed by pellets. Smoke f2 exits the dryer 1 and enters the condenser 53, where it is divided into quantities controlled by corresponding valves V to reach the smoke purifier 55. Smoke f2 emanating from the first heat exchanger 50 reaches the same purifier 55. System circulation begins with dewatered sludge with a drying percentage between 23% and 28% entering the dryer 1 via a rotating hopper along arrow F. This mechanism allows sludge loading but does not allow heat treatment air to escape.

[0107] Therefore, the sludge clumps located at the starting point of the screw conveyor are violently mixed and very slowly conveyed to the end of the first section to be loaded into the second countercurrent section.

[0108] During the "back and forth" process, the mass gradually dries as moisture is transferred to the hot airflow. The exchange surface between the material to be dried and the airflow is fundamental to the system's efficiency. The screw conveyor allows for a variation in revolutions per minute between 0.1 and 50 and higher, while maintaining a consistent flow rate due to the presence of slender elements with adjustable longitudinal angles. This enables energy mixing. Furthermore, it allows for specialized configuration of the aerodynamic flow via the screw and the use of venturi tubes to fluidize the material to be dried, while placing the system in a floating bed state, thereby determining the maximum exchange surface.

[0109] The bottom screw conveyor is not a tube-type integral conveyor, but has a central shaft that rotates on the trough. This fact prevents the dry product from overflowing or being entrained in the upper airflow.

[0110] The dried sludge is placed in a bottom rotary hopper and conveyed from the bottom rotary hopper to the incinerator 51 via a screw conveyor 56 and a granulator 57. A variable amount of granules (8% to 12%) with significantly lower calorific value is added to the incinerator to maintain the permanent flame temperature above 800°C.

[0111] The heat generated is transferred to the drying unit via an airflow heated by heat exchanger 50. The hot airflow is provided by a fan 54 located downstream of the drying unit 1. The heated air f2 carrying moisture passes through a condenser 53 before being recirculated at a percentage varying from 0% to 100%, from which condensate carrying derivative substances is extracted and returned to the head of the drying unit 1 or used for alternative purposes.

[0112] Non-recirculated air and exhaust fumes from the burner in the system are treated by air purifier 55, which consists of a wet cyclone separator, a fluidized bed drain valve, a countercurrent percolation filter, a layered degasser, and an activated carbon adsorption tower.

[0113] The system can be fully controlled by a dedicated computer system, particularly in managing the inlet flow rate, changing the revolutions per minute of the screw conveyor, altering the humidity gradient within sections of the loop, managing necessary airflow, and adjusting the angles and configurations of elongated elements. This allows the system to adapt to diverse operating conditions and achieve maximum efficiency.

[0114] Revise

[0115] It should be understood that various modifications can be made to the embodiments described above. Such modifications may involve equivalents and other features known in the design, manufacture, and use of systems including screw conveyors and their components, and may be used as replacements for or supplements to the features already described herein. Features of one embodiment may be replaced or supplemented by features of another embodiment.

[0116] The system does not have to be a drying system, but can be another form of system, such as a fermentation system, for example in the form of a spiral bioreactor.

[0117] Although claims have been made for specific combinations of features in this application, it should be understood that the scope of the disclosure of this invention also includes any novel feature or any novel combination of features (whether express or implied) or any generalization thereof, whether it relates to the same invention as currently claimed in any claim and whether it alleviates any or all of the same technical problems as this invention. The applicant hereby notifies that new claims may be made for such features and / or combinations of such features during the examination of this application or any further application derived therefrom.

Claims

1. A screw conveyor, comprising: A helical element having a longitudinal axis and comprising: The main helix, comprising multiple turns; and A secondary spiral, comprising multiple turns, is mounted on the primary spiral and is rotatable relative to the primary spiral about the longitudinal axis. A set of slender components spans the main helix and the secondary helix; The first end of each elongated member is attached to either the primary helix or the secondary helix via a cylindrical hinge.

2. The screw conveyor of claim 1, wherein the second end of each elongated member is slidably attached to one of the main screw or the secondary screw.

3. The screw conveyor of claim 1, wherein the second end of each elongated member is located in a sliding guide rail attached to one of the main screw or the secondary screw.

4. The screw conveyor of claim 2, wherein the second end of each elongated member is located in a sliding guide rail attached to one of the main screw or the secondary screw.

5. The screw conveyor of claim 3, wherein the sliding guide rail includes a "U"-shaped member providing a slot, the second end of the elongated member being slidably disposed in the slot.

6. The screw conveyor of claim 4, wherein the sliding guide includes a "U"-shaped member providing a slot, the second end of the elongated member being slidably disposed in the slot.

7. The screw conveyor according to claim 1, further comprising: Multiple slots are provided in the main helix and / or the secondary helix; Multiple retaining pins, each pin passing through a corresponding slot; The slot and pin are arranged to guide the secondary helix to rotate about the longitudinal axis relative to the primary helix.

8. The screw conveyor according to claim 2, further comprising: Multiple slots are provided in the main helix and / or the secondary helix; Multiple retaining pins, each pin passing through a corresponding slot; The slot and pin are arranged to guide the secondary helix to rotate about the longitudinal axis relative to the primary helix.

9. The screw conveyor according to claim 3, further comprising: Multiple slots are provided in the main helix and / or the secondary helix; Multiple retaining pins, each pin passing through a corresponding slot; The slot and pin are arranged to guide the secondary helix to rotate about the longitudinal axis relative to the primary helix.

10. The screw conveyor according to claim 4, further comprising: Multiple slots are provided in the main helix and / or the secondary helix; Multiple retaining pins, each pin passing through a corresponding slot; The slot and pin are arranged to guide the secondary helix to rotate about the longitudinal axis relative to the primary helix.

11. The screw conveyor according to claim 5, further comprising: Multiple slots are provided in the main helix and / or the secondary helix; Multiple retaining pins, each pin passing through a corresponding slot; The slot and pin are arranged to guide the secondary helix to rotate about the longitudinal axis relative to the primary helix.

12. The screw conveyor according to claim 6, further comprising: Multiple slots are provided in the main helix and / or the secondary helix; Multiple retaining pins, each pin passing through a corresponding slot; The slot and pin are arranged to guide the secondary helix to rotate about the longitudinal axis relative to the primary helix.

13. The screw conveyor according to any one of claims 1 to 12, further comprising: A rod, coupled to the secondary helix, causes the secondary helix to rotate about the longitudinal axis relative to the primary helix when rotated.

14. The screw conveyor according to claim 13, further comprising: An actuator, coupled to the rod, is used to rotate the secondary helix relative to the primary helix to a desired angular position and to immediately lock the secondary helix at the desired angular position when it is in that position.

15. The screw conveyor of claim 14, wherein the actuator includes a hydraulic adjustment device.

16. A fermentation system comprising at least one screw conveyor, said at least one screw conveyor comprising the screw conveyor according to any one of claims 1 to 15.

17. A drying apparatus comprising at least one screw conveyor, said at least one screw conveyor comprising a screw conveyor according to any one of claims 1 to 15.

18. A drying apparatus comprising a plurality of screw conveyors, each screw conveyor comprising a screw conveyor according to any one of claims 1 to 15.

19. The drying apparatus according to claim 18, further comprising: Supporting framework; Front, back, and top walls; A hopper for receiving the material to be dried through an inlet in the top wall, and a rotary cylindrical valve downstream of the hopper, the rotary cylindrical valve being close to the front; The screw conveyor is rotatably supported on the front and rear heads, and the rear head is provided with a sprocket and one or more drives for propelling the material to be dried to the outlet of the device; The drying equipment also includes: A heated air system is adapted to supply heated air to the plurality of screw conveyors for dehydrating the material to be dried, wherein the drying equipment is arranged to allow humid air to escape through a first opening in the top wall.

20. The drying apparatus of claim 19, wherein the screw conveyors are arranged in a row above each other, wherein the first lower screw conveyor includes a screw element arranged in a trough, and wherein the second intermediate screw conveyor and the third upper screw conveyor have their respective screw elements, the main screw of which is rigidly connected to a perforated tube surrounding and rotating integrally with the screw element.

21. The drying apparatus of claim 20, wherein the array of screw conveyors is housed in one or more housings having openings and adapted to convey the heated air, wherein the heated air system includes at least one supply pipe, a secondary pipe, and at least one conveying box, the at least one conveying box being supported by the support frame and adapted to directly supply heated air from the one or more housings to the intermediate screw conveyor and the upper screw conveyor through a second opening.

22. The drying apparatus of claim 21, wherein the one or more shells have identical facing protrusions to form a prismatic shell, and the perforated tube has longitudinal fins that project outward and are adapted to interact with the facing protrusions to retain the heated air in the prismatic shell before it leaves as humid air through the opening.

23. The drying apparatus according to any one of claims 19 to 22, wherein the one or more drives comprise a gear motor mounted on the rear end and connected to the sprocket by means of a flexible transmission member.

24. The drying apparatus according to any one of claims 19 to 22, wherein the one or more drives comprise a plurality of gear motors, each gear motor being arranged to drive a respective sprocket.

25. The drying apparatus according to claim 22, further comprising: Multiple hygrometers are installed near the screw conveyor.

26. The drying apparatus according to claim 23, further comprising: Multiple hygrometers are installed near the screw conveyor.

27. The drying apparatus according to claim 24, further comprising: Multiple hygrometers are installed near the screw conveyor.

28. The drying apparatus according to claim 18, further comprising: Multiple hygrometers are installed near the screw conveyor.

29. A system for use with a drying apparatus according to any one of claims 19 to 27, the system comprising: Dehydrated waste incinerator; The first fan is used to supply air from the outside; A heat exchanger is used to supply heated air to the drying equipment on one side downstream of the dehydrated waste incinerator and on the other side downstream of the first fan; A granulator is located downstream of the outlet of the drying equipment for the material to be dried and upstream of the incinerator; A condenser is used to remove the humid air from the drying equipment using tap water, which enters through a branch line. The first pipe exiting the condenser is for wastewater, and the second pipe is for returning the water to the tap water. A second fan, located downstream of the condenser, is used to recirculate the smoke within the drying equipment. as well as A fume purifier is adapted to receive cooling air from the condenser and fume from the heat exchanger as a recirculation alternative, wherein the pipe exiting the purifier is used for wastewater.

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