WO2008063347A2

WO2008063347A2 - Pellet extrusion device

Info

Publication number: WO2008063347A2
Application number: PCT/US2007/022705
Authority: WO
Inventors: Leonard Reggie; Adam Reggie; Bryan Reggie
Original assignee: Leonard Reggie; Adam Reggie; Bryan Reggie
Priority date: 2006-11-10
Filing date: 2007-10-26
Publication date: 2008-05-29
Also published as: WO2008063347A3; WO2008063347A8

Abstract

A reliable, energy-efficient pallet extrusion system [100] is described which creates pellets [170] from a biomass material [16], it employs equipment which pre-processes the biomass material [16]. Biomass material [16] is then provided to a pellet mill [1000]. The blomass [16] material is provided into a drum [1300] of a pellet mill [1000]. The pellet mill [1000] has a plurality of extrusion holes [1200] and at least one roller [1400]. The rollers [1400] have protrusions [1420] sized and shaped to match up with the holes [1200] of the drum [1300], As the drum [1300] and rollers [1400] turn, protrusions [1420] of roller [1400] meet with holes [1200] of drum [1300]. pressing the blomass [16] out of extrusion holes [1200] as pellets [170]. Since the protrusions [1420] only align with holes [1200], the biomass [16] is extruded through the plurality of extrusion holes [1200] without a significant increase in pressure.

Description

Pellet Extrusion Device

CROSS REFERENCE TO RELATED APPLICATIONS

This PCT Patent Application is a Continuation-In-Part Patent Application and claims priority from US Provisional Patent Application "Pellet Extrusion Device" Ser. No. 60/858,071 filed Nov. 10, 2006 by Leonard Reggie and Adam Reggie. All material of the parent application is incorporated by reference as if it were set forth in its entirety herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an energy efficient pellet extrusion device.

2. Discussion of Related Art A pellet extrusion device is a machine used to create pellets from a mixture a wet ingredient, such as water, and a dry substrate. The pellets are used as food for animals or for combustion in stoves and boilers.

If used for feeding animals, the liquid could be some nutrient, such as molasses, or vegetable oil and the substrate could be grass, or animal feed.

If used for combustion, the materials may be water, oils, glycerin and cellulosic material, such as grasses, wood products, papers, etc. This results in a renewable source of energy. Due to their size and shape, pellets are automatically fed into a burner with an automatic feed system, such as a screw feeder.

Pellet stoves act as a heating device for structures and first became popular during the oil shortages of the 1970s and as people became used to higher prices their popularity grew slowly. They became more sophisticated, and more physically attractive. Most stoves are now quite attractive. Commercial models are available, which can heat large buildings, or be used to generate electricity using various renewable fuel sources such as corn, cherry pits, wood pellets, etc.

Many countries offer a small subsidy for their installation, and hence today they are used in modern central heating systems, notably in Austria and Germany and other parts of Europe, as well as North America. In fact there are currently more than 600,000 homes in North

America using wood pellets for heat, in freestanding stoves, fireplace inserts and even furnaces. In North America pellets are produced in large manufacturing facilities and are available for purchase at fireplace dealers, nurseries, building supply stores, feed and garden supply stores and some discount merchandisers.

The pellets as stated are made at manufacturing facilities by a high powered pellet mill, which compresses the biomass material through a plurality of extrusion holes of the size required. The act of compressing materials is the result of rotating rollers forcing the biomass material through the plurality of extrusion holes, resulting in pellets of the desired size. The high pressure of the rollers not only forces the pellets out but at the same time causes the temperature of the wood to increase, binding each pellet together as it cools.

One such pellet mill can be seen in United States Patent 5,744,186 disclosing a method and pellet mill apparatus for the continuous preparation of animal feed pellets. It describes cooking a grain mash with steam under high pressure and to an extrusion die.

Another such pellet mill can be seen in United States Patent 5,486, 102 disclosing a pellet mill for creating feed product. This has a pelleting die with a plurality of extrusion holes for extruding the feed product; rollers, rotatable relative to the pelleting die. These force the feed product through the extrusion holes. This device intensively mixes and shears the feed product before introducing the feed product to the pelleting die.

The problem with the systems described above is that forcing the material to be extruded through the plurality of extrusion holes via the use of rollers results in wasting a good amount of energy. This energy is then effectively lost, in the form of thermal energy, which in turn leads to greater inefficiencies. Also, due to the increased forces on the devices, tend to mechanically wear and fail.

Currently, there is a current need for an energy efficient extrusion device for the production of pellets.

SUMMARY OF THE INVENTION

One embodiment of the present invention is an energy efficient pallet extrusion system 100 for creating extruded pellets 170 comprising:

1) a drum 1300 having a curved surface with a plurality of extrusion holes, for containment of biomass 16 intended to be processed;

2) at least one roller 1400 having a plurality of protrusions 1420 mounted in close proximity to the drum 1300, in which each protrusion 1420 is sized and shaped to meet with the extrusion holes 1200 of the drum 1300 when the drum 1300 and the roller 1400 are properly aligned and rotated together each at a predefined relative rotational speed, thereby forcing any material between the protrusions 1420 and extrusion holes 1200 through at least one extrusion hole 1200 on the drum 1300 to create pellets 170; 3) a timing unit 6000 connected to a motor source for driving the drum 1300 and at least one roller 1400 such that the drum 1300 and the roller 1400 are properly aligned and rotated at the predefined rotational speed.

OBJECTS OF THE INVENTION

It is an object of the present invention to provide an extrusion system which incorporates a design for the production of pellets which is more energy efficient than the prior art devices. It is an object of the present invention to provide an extrusion system which incorporates an energy efficient design for the lower output consumer such as farmers or home user.

It is an object of the present invention to provide an extrusion system which incorporates a design which is more cost effective. It is an object of the present invention to provide an extrusion system which incorporates a smaller, more compact design.

It is an object of the present invention to provide an extrusion system which incorporates a more resilient and reliable design.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages of the instant disclosure will become more apparent when read with the specification and the drawings, wherein:

FIG. 1 is an overall side elevational view of a pellet extrusion system according to the present invention.

FIG. 2 is a plan view of the pellet extrusion device of FIG. 1.

FIG. 3 is a side elevational view of a prior art extrusion system. FIG. 4 is a perspective view of one embodiment of an extrusion device according to the present invention in operation.

FIG. 5 is a partial cut-away perspective view of the embodiment of an extrusion device shown in FIG. 4 according to the present invention.

FIG. 6 is a cross-sectional plan view of the embodiment of the extrusion device shown in FIGs. 4 and 5.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is an overall side elevational view of a pellet extrusion system according to the present invention. FIG. 2 is a plan view of the pellet extrusion system of FIG. 1. The overall system will be described with reference to FIGs. 1 and 2.

A platform 200 holds the apparatus for creating pellets. In this case the platform 200 is a trailer having wheels 210. It may be taken to a location where there is biomass material 16 to be palletized.

External power is supplied to the platform 200. One example is a external power shaft 230 from a tractor or other equipment connected through a clutch 1910 to an internal drive train 1900.

Internal drive train 1900 drives a number of components of the system.

Material, such as baled grasses are placed on a feeder tray 2100 which is lifted to contact bale to bale breaker 2000. Bale breaker 2000 slowly grinds a bale into base material at a rate which matches the rate at which the base material is needed. Power is provided to the bale breaker form the internal drive train through a breaker drive 1940. The ground material is then moved out of the bale breaker 2000 by a conveyor 2200 to a shredder 3000.

The ground material form the bale breaker may be sucked up by a vacuum and provided to shredder 3000. Also, in another alternative embodiment, the material may be pre-shredded into a course material by a pre- shredder (not shown) then sucked into the shredder 3000. The base material is provided to a shredder 3000. Shredder shreds the base material to the proper consistency. Internal drive train 1900 drives a shredder drive 1930 which powers the shredder.

Blower 3100 creates a vacuum and sucks up the shredded material. The shredded material is then passed into a cyclone separator 3400 that takes the shredded material out of the air. An air compressor 3600 aids in creating the vacuum to move the shredded material into the separator.

The proper sized particles are then passed through a filter 3500 to separate the material from the air and into a vertical storage bin 4000.

Blower 3100 and shredder 3000 are powered by internal drive train 1900.

A secondary drive 1920 also runs a generator 3700 which creates any electric power. Some of which may be used for components of the system.

A feeder 5000, takes the material from the bottom of storage bin 4000 and drops the material into a pellet mill 1000 which pellets the material.

Feeder 5000 may be constructed of a blower which creates a suction. The suction pulls the biomass material [16] through a small cyclone separator and into pellet mill 1000.

In an alternative embodiment, feeder 500 may include a screw-type device which feeds biomass material [16] into pellet mill 1000.

Pellet mill 1000 is driven by a drive shaft 1610 driven by internal drive train 1900. The pellet mill 1000 is described in greater detain in connection with the remaining figures. A water tank 1540 provides water through a water line 1541 to pellet mill 1000 to aid in pelleting the biomass (16 of FIG. 6).

A pellet discharge unit 1850, which may be a conveyer, collects the pellets and provides them to a pellet storage device (not shown). FIG. 3 show one prior art pellet extrusion device 10. Here, a mix of extrudable materials, collectively referred to as biomass 16, are mixed and placed within a die 110. Die 110 may be a flat or curved surface. Biomass materials 16 may be grasses, cellulosic material, wood, wood byproducts, leaves, twigs, papers, or other material which can be burned.

The die 110 rotates in direction marked by arrows "A" and rollers 140 rotate in direction marked by arrows "B" about an axle 141.

Die 110 has a plurality of extrusion holes 120. Roller 140 presses biomass 16 against die 110. As roller 140 presses biomass against die 110, biomass 16 is extruded through holes 120. A stationary cutting device 180 cuts off the extruded pellets 17 as the device rotates.

There are regions between the roller 140 and die 110 marked 191, 193 and 195. Regions 191, 195 are the regions between the holes 120 and between roller 140 and die 110. Similarly, region 193 is the region above a hole 120 and below roller 140. As roller 140 moves across die 110, pressure is exerted on the biomass 16 in each of these regions. Since the biomass 16 in region 193 is allowed to be extruded out of hole 120, there is not a great deal of pressure exerted in region 193.

However, in regions 191, 195, the biomass is not easily allowed to exit the region, and the pressure increases. The higher the viscosity of the biomass 16 and the greater the spacing between the holes 120, the greater the pressure that is produced. Since this compression requires energy (which is typically wasted in the form of heat), and performed repeatedly, there is a large waste of energy. This device is typical of the prior art pellet extrusion devices. These tend to use a large amount of energy to produce the pellets 17. This is because much of the energy is wasted.

Also, due to the large amount of pressure, this design requires stronger equipment. This design also places undue stress on the equipment. Over time, the increased stress leads to mechanical wear, failure, and increased repair costs.

FIG. 4 is a perspective view of an energy efficient, reliable pellet extrusion system 1000 according to the present invention in operation. Since this is not a cut-away view, the internal parts are not shown.

Substrate material intended to be pressed into pellets is provided to a hopper 1510. A substrate feeder 1520 moves substrate material from hopper 1510 into a drum 1300 having a plurality of holes 1200. Substrate feeder 1520 may employ a screw drive (not shown) or other known devices for feeding material into drum 1300.

A liquid may be provided through a liquid feeder 1530 into drum 1300 which is mixed with the substrate creating biomass. Drum 1300 also has a cover 1330 for containing the biomass in drum 1300.

The drum 1300 rotates in a rotational direction shown by arrows marked "C". It rotates causing the internal biomass to be forced against the inside wall of drum 1300.

A drive shaft 1610 is connected to a rotating power source, such as an engine (not shown). Drive shaft 1610 connects to drum 1300, drum shaft 1310 and timing unit 6000. Drive shaft 1610 rotates drum 1300, drum shaft 1310 and timing unit 6000 in the rotational direction according to the arrows marked "C". Timing unit 6000 employs either belts, gears, chains, or other means for providing the proper timing and gear ratio between the rotation of drive shaft 1610 to roller shafts 1410 to properly power internal rollers (not shown) to extrude the biomass out of the plurality of holes 1200 in drum 1300 as extruded pellets 170.

It was determined that by increasing the heat of the drum 1300, it is more easily extruded. Therefore, one embodiment includes a heat inlet 1540 which injects hot air or steam onto drum 1300 causing the drum 1300 to rise in temperature in order to remove excess moisture and cause the biomass (16 of FIG. 6) to bind together.

Alternative known methods of causing biomass to be heated may also be used, such as injecting steam into biomass, or heating internal rollers ( 1400 of FIGs. 5, 6) .

In an optional embodiment, a cutting device 1800 may be employed used for shearing the pellets 170 from extrusion holes 1200. The biomass is squeezed through the plurality of extrusion holes 1200 and the extruded biomass is cut off by cutters 1800. FIG. 5 is a partially cut-away perspective view of the present invention of the embodiment shown in FIG. 2. This embodiment shows only the inside of the drum 1300 and associated functional elements for clarity purposes.

It is shown here that the rollers 1400 employ a plurality of protrusions 1420 sized and spaced to match up with each of the holes (1200 of FIG. 4) of drum 1300 as the roller 1400 turns and meets with the inner wall 1320 of drum 1300.

Many of the parts of FIG. 4 are repeated here, and have the same function. The timing unit 6000 functions to power and turn rollers 1400 at the proper rate in order to maintain an exact relationship in which each protrusion 1420 meets with a hole (1200 of FIG. 2) of drum 1300 when the protrusion is closest to the drum inner wall 1320. Therefore, there must be a very accurate drive relationship between the rollers 1400 and drum 1300 governed by timing unit 6000.

FIG. 6 is a cross- sectional view through "IV and "IV of FIG. 2 further detailing the present invention. Here substrate feeder 1520 and liquid feeder 1530 are shown in cross section.

Roller 1400 employs protrusions 1420 and move in the rotation direction shown by arrows "C". Drum 1300 also moves in the direction marked "C. It can be seen here that biomass 16 is forced into the holes 1200 in drum 1300 causing it to push out other biomass 16 in the holes 1200. This extruded biomass is cut or broken off by cutting device 1800 into pellets 170.

The protrusions 1420 and their respective alignment is an important design feature because it is this component of the present design that allows for the energy efficient production of pellets 170.

Therefore, timing unit (6000 of FIGs. 1, 2) accurately drives rollers 1400 in the proper gearing ratio and rotational offset relative to drum 1300 so as to accurately align protrusions 1420 with holes 1200.

One method of producing a similar device would be to design it so that the protrusions 1420 fit into holes 1200. This would be advantageous in pushing the created pellets 170 out of the extrusion holes 1200. However, a device such as this would have to take into account the difference in angle of the protrusion as it enters the hole and as it leaves the hole as the roller rolls past the hole. Therefore, the protrusion should be significantly smaller than the hole to account for this angled entry and exit. A smaller protrusion would only partially press biomass into the hole, and leave a residual amount of biomass in the hole. This could cause partial or full blockage of the holes. If there was a misalignment between the protrusions and holes in a design where the protrusions fit into the holes, it would cause increased mechanical binding and wear. This would also waste a great deal of input energy. Therefore, it can be seen that in addition to the advantages described, the present invention is beneficial in that the protrusions 1420 come close to extrusion holes 1200, or only slightly enter holes 1200. Therefore, the protrusions could be almost the same size as holes 1200, or bigger causing efficient extrusion. Since the protrusions 1420 only meet or slightly enter holes 1200, slight misalignments between them does not result in mechanical binding or significant wear or loss of input energy.

Since the present invention is not as sensitive to slight misalignments, it may be developed with larger manufacturing tolerances and have fewer quality control issues. This results in less expense, and a more reliable product.

The example shown and described above is only illustrative on one embodiment of the invention. Other embodiments which fall under the present invention may also be used. For example, if the drum is rotated at sufficient speed, the biomass 16 is thrown to the inside wall 1320 of drum 1300. It is therefore irrelevant if the drum axis is oriented vertically or horizontally. Similarly, if substrate feeder (1520 of FIG. 2) employs gravity- independent feeding mechanisms such as a screw drive, it may be oriented in a different direction. Also, hopper 1510 of (FIG. 2) may require re-orienting.

The present invention may be stationary and have a dedicated electric, gasoline, diesel, or other motor powering the system. It may also be designed as a retrofit to attach to existing machinery. For example, it may attach to the attachment drive unit of a common farm tractor, or other equipment.

Other types of extrusion material may also be used for other purposes. For example, material may be extruded to make kitty litter pellets, animal feed pellets, inert packing pellets, or other extruded pellets.

This system reduces the input energy required to produce pellets thereby reducing the wear on the system. Mechanical wear typically causes mechanical failure. It also requires increased maintenance, and part replacement.

The design of the present invention results in a more reliable system which does not require repair as often. This results in the increased life of the extrusion device as well as the decreased operational and maintenance costs over traditional prior art pellet mills.

Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for the purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention.

Claims

CLAIMSWhat is claimed is:

1. An energy-efficient pellet extrusion device [100] for creating extruded pellets [170] from a biomass [16] comprising: a) a drum [1300] having a curved surface with a plurality of extrusion holes [1200], for containment of biomass [16] intended to be processed; b) at least one roller [1400] having a plurality of protrusions [1420] mounted in close proximity to the drum [1300], in which each protrusion [1420] is sized and shaped to meet with the holes

[1200] of the drum [1300] when the drum [1300] and the roller [1400] are properly aligned and rotated together each at a predefined relative rotational speed; c) a timing source [6000] for driving the drum [1300] and at least one roller [1400] such that the drum [1300] and the roller [1400] are properly aligned and rotated at the predefined rotational speed thereby forcing said biomass [16] between the protrusions [1420] and drum [1300] through at least one hole [1200] on the drum [1300] to create extruded pellets in a more efficient manner than prior art devices.

2. The energy-efficient pellet extrusion device [100] of claim 1 further comprising: a feeder [5000] for properly feeding biomass material [16] into the pellet mill [1000].

3. The energy-efficient pellet extrusion device [100] of claim 1 wherein the feeder [5000] comprises: a vacuum device which sucks biomass material [16] though a cyclone separator.

4. The energy-efficient pellet extrusion device [100] of claim 1 wherein the feeder [5000] employs a screw-type device to feed the biomass material [16] to the pellet mill [1000].

5. The energy-efficient pellet extrusion device [100] of claim 2 further comprising: a storage bin for holding the biomass material [16] and providing it to the screw feeder [5000] for properly feeding the biomass [16] into the pellet mill [1000].

6. The energy-efficient pellet extrusion device [100] of claim 5 further comprising: a blower [3500] for blowing biomass material [16] into the storage bin [4000] to fill it.

7. The energy-efficient pellet extrusion device [100] of claim 6 further comprising: a shredder [3000] for shredding the biomass material [16] prior to blowing it into the storage bin [4000].

8. The energy-efficient pellet extrusion device [100] of claim 7 further comprising: a bale breaker [2000] for receiving and grinding bales of biomass into loose biomass material [16] which the pellet mill [1000] extrudes into pellets.

9. The energy-efficient pellet extrusion device [100] of claim 8 further comprising: a breaker drive [1940] coupled to the drive shaft [1610] for powering the bale breaker [2000].

10. The energy-efficient pellet extrusion device [100] of claim 1 wherein there are at least two rollers [1400].

11. The energy-efficient pellet extrusion device [100] of claim 1 wherein the protrusions [1420] only partially enter the holes [1200].

12. A method for producing pellets in a more efficient manner comprising the steps of: a) providing a drum [1300] having a plurality of holes [1200] through it; b) providing at least one roller [1400] inside of the drum [1300] having a plurality of protrusions [1420] located to meet, but not enter the holes [1200] of the drum [1300] as the roller [1400] and drum [1300] are turned; c) providing a biomass material [16] inside of drum [1300]; and d) turning roller [1400] and drum [1300] in the same rotational direction to cause protrusions [1420] to extrude the biomass material [16] out of holes [1200] to produce pellets [170] in a more efficient manner than prior art devices.

13. The method of claim 12 further comprising the step of: feeding biomass material [16] into the pellet mill [1000] with a feeder [5000].

14. The method of claim 13 further comprising the step of: holding the biomass material [16] in a storage bin [4000] and providing it to the feeder [5000] for properly feeding the biomass [16] into the pellet mill [1000].

15. The method of claim 13 wherein the step of feeding biomass material [16] into the pellet mill [1000] comprises the step of: creating a vacuum to suck the biomass material [16] through a cyclone separator to feed the biomass material [16] into the pellet mill [1000].

16. The method of claim 14 further comprising the step of: blowing biomass material [16] into the storage bin [4000] with a blower

17. The method of claim 16 further comprising the step of: shredding the biomass material [16] prior to blowing it into the storage bin [4000].

18. The method of claim 17 further comprising the step of: grinding bales of biomass into loose biomass material [16] prior to blowing the biomass material [16] into the storage bin [4000].

19. The method of claim 12 wherein at least two rollers [1400] are provided.

20. The method of claim 12 wherein the protrusions [1420] only partially enter the holes [1200].