COMPRESSION APPARATUS AND METHOD

• US 20110011283A1
• Filed: 07/16/2010
• Published: 01/20/2011
• Est. Priority Date: 07/17/2009
• Status: Active Grant

• Current Assignee: Mascoma Canada Inc.
• Original Assignee: Sunopta Bioprocess Inc. (Lallemand Inc.)
• Inventors: Burke, Murray J.
• Granted Patent: US 8,561,533 B2
• Time in Patent Office: Days
• US Class Current: 100/35
• CPC Class Codes: B30B 11/224 Extrusion chambers
• CPC Class Codes: B30B 11/24 using screws or worms
• CPC Class Codes: B30B 11/265 with precompression means
• CPC Class Codes: B30B 9/125 Control arrangements
• CPC Class Codes: B30B 9/18 with means for adjusting the outlet for the solid

Abstract

An apparatus is provided for compressing a loose solid feedstock. The apparatus includes a two stage compressor. The first compression stage is a screw compressor. The second compressor stage is a reciprocating compressor. The reciprocating compressor operates co-axially with, and receives its feed from, the screw compressor. A choke cone maintains pressure in the outfeed from the compressor stages. The reciprocating compressor includes a piston that is driven by a pair of hydraulic rams. The position and operation of the hydraulic rams, the screw conveyor, and the choke cone is monitored by sensors. The reciprocating compressor, the screw conveyor, and the choke cone are all adjustable in real time to control the compression of the feedstock according to a pre-programmed schedule that need not have equal compression and retraction strokes. The operation of the screw conveyor may be advanced or eased off depending on the motion of the reciprocating compressor. The operation of the choke cone may be actively controlled to obtain a coordination with the compressor stages.

Claims

1. A power transmission apparatus for a compression stage in a compressor for loose packed materials the compressor having a first compression stage and a second compression stage, said power transmission apparatus comprising:

a compressor piston of the second compressor stage, said compressor piston being shaped to extend about at least a portion of the first compression stage and to be reciprocally movable with respect thereto;

said compressor piston having a first end and a second end;

said first end of said compressor piston being an output end thereof, and being shaped to conform to a co-operating mating cylinder within which said compressor piston is mounted to reciprocate in a longitudinal direction;

said second end being distant from said first end;

said power transmission apparatus having a movable power input interface at which motive force is applied to said compressor piston;

said power input interface having a fixed position relative to said first end of said compressor piston;

said power transmission apparatus having a stationary reaction datum, said compressor piston being movable in longitudinal reciprocation relative to said stationary reaction datum;

said power input interface being driven along a single degree of freedom of motion relative to said stationary reaction datum.

2. The power transmission apparatus of claim 1 wherein said power transmission is free of slack between said power input interface and said first end of said compressor piston.

3. The power transmission apparatus of claim 1 wherein:

said power transmission apparatus includes an actuator cylinder arrangement that includes at least a first actuator cylinder;

said stationary reaction datum is defined by a first end of said first actuator cylinder; and

said power input interface is defined at least in part by said first actuator piston operating within that first actuator cylinder.

4. The power transmission apparatus of claim 3 wherein, when viewed perpendicular to said longitudinal direction, said compressor piston is located in an intermediate position relative to said actuator cylinder arrangement.

5. The power transmission apparatus of claim 3 wherein said actuator cylinder arrangement includes a plurality of actuator cylinders arrayed in substantially balanced spacing about said compressor piston.

6. The power transmission apparatus of claim 3 wherein:

said compressor piston has a body extending between said first and second ends thereof, and has an outwardly extending flange mounted externally thereto; and

said outwardly extending flange defines at least a portion of said first actuator piston.

7. The power transmission apparatus of claim 3 wherein said compressor piston has an externally extending peripheral wall, said wall fits in co-operating relationship within said first actuator cylinder, and said wall has at least a first face positioned in opposition to said stationary reaction datum, and said wall defines said first actuator piston.

8. The power transmission apparatus of claim 7 wherein:

said compressor piston has a bore formed longitudinally therethrough to accommodate said first compression stage; and

said first actuator cylinder, said first face of said externally extending peripheral wall of said compressor piston, said first end of said compressor piston and said bore formed in said compressor piston are all circular in cross-section and concentric.

9. The power transmission apparatus of claim 1 wherein the first compressor stage includes a screw compressor mounted concentrically within said piston.

10. The power transmission apparatus of claim 1 wherein said compressor piston is annular and has an axially extending passage formed therethrough to accommodate the second compression stage.

11. A power transmission apparatus for a compression stage in a compressor for loose packed materials the compressor having a first compression stage and a second compression stage, said power transmission apparatus comprising:

a compressor piston of the second compressor stage, said compressor piston being shaped to extend about at least a portion of the first compression stage and to be reciprocally movable with respect thereto;

said compressor piston having a first end and a second end;

said first end of said compressor piston being an output end thereof, and being shaped to conform to a co-operating mating cylinder within which said compressor piston is mounted to reciprocate in a longitudinal direction;

said second end being distant from said first end;

said power transmission apparatus having a movable power input interface at which motive force is applied to said compressor piston;

said power input interface having a fixed position relative to said first end of said compressor piston;

said power transmission apparatus having a stationary reaction datum, said compressor piston being movable in longitudinal reciprocation relative to said stationary reaction datum;

said power input interface being driven along a single degree of freedom of motion relative to said stationary reaction datum;

said power transmission apparatus includes a head and a plurality of power transmission members;

said second end of said compressor piston being mounted to said head, said head extending transversely of said second end of said compressor piston;

said power transmission members of said plurality of transmission members are each movably mounted to a stationary power input apparatus;

said power transmission members are connected to said head; and

said power transmission members are each restricted to a single degree of freedom of motion from said stationary power input apparatus to said head.

12. The power transmission apparatus of claim 11 wherein there is no slack in said power transmission members between said stationary power input apparatus and said second end of said compressor piston.

13. The power transmission apparatus of claim 11 wherein said power transmission members are connected to said head at moment connections.

14. The power transmission apparatus of claim 11 wherein said apparatus includes a controller operable to monitor motion of each of said transmission members and operable to co-ordinate motion of said transmission members relative to each other.

15. The power transmission apparatus of claim 11 wherein:

each of said power transmission members is a shaft;

said apparatus includes said stationary power input apparatus;

said power input apparatus includes drive cylinders and input power pistons; and

each shaft of said power transmission members extends into a respective one of said drive cylinders and has a respective one of said input power pistons mounted thereto by which to drive reciprocation thereof.

16. The power transmission apparatus of claim 11 wherein each of said power transmission members is a shaft held in a pair of first and second, axially spaced apart slide bearings that allow only longitudinal translation of said respective transmission members.

17. The power transmission apparatus of claim 15 wherein:

each of said power transmission members is a shaft held in a pair of first and second, axially spaced apart slide bearings that allow only longitudinal translation of said respective transmission members;

each of said power transmission members is a shaft;

said apparatus includes said stationary power input apparatus;

said power input apparatus includes drive cylinders and input power pistons; and

each shaft of said power transmission members extends through a respective one of said drive cylinders and has a respective one of said input power pistons mounted thereto by which to drive reciprocation thereof between said pair of first and second axially spaced apart slide bearings.

18. The power transmission apparatus of claim 11 wherein, in cross-section transverse to the longitudinal direction said transmission members define vertices of a polygon;

said piston has a centerline axis of reciprocation; and

said centerline axis of reciprocation lies within said polygon.

19. The power transmission apparatus of claim 11 wherein said power transmission members include a first power transmission member and a second power transmission member, each of said first and second power transmission members having an axis of reciprocation, said piston has a centerline axis of reciprocation;

and said axes of reciprocation of said first and second power transmission members are substantially diametrically opposed relative to said piston centerline axis of reciprocation.

20. The power transmission apparatus of claim 11 wherein both said power transmission members and said compressor piston are located longitudinally to one side of said head, said apparatus includes a spider, said spider defines mountings for said stationary power input apparatus and said spider has a passageway defined therethough in which to mount the mating cylinder.

21. A two stage compressor feed apparatus operable to compress loose feedstock material, said feed apparatus comprising:

a first compressor stage and a second compressor stage;

said first compressor stage having a screw, said screw having a volute operable to drive the feedstock forward in an axial direction while compressing the feedstock;

said second compressor stage having a compressor piston mounted to reciprocate in the axial direction, said second stage compressor piston having an axial accommodation permitting an end of said screw to extend therethrough;

said second compressor stage having a stator and rams mounted to said stator in a rigidly fixed orientation parallel to said axial direction;

said second compressor stage having a cylinder mounted to said stator, said cylinder being a mating cylinder for co-operation with said compressor piston;

said second stage compressor piston having a first end and a second end;

said second compressor stage includes a head;

said second end of said compressor piston being mounted in a fixed orientation to said head;

said first end of said compressor piston being distant from, and being oriented to face away from, said head;

said rams including shafting extending to said head, said shafting constraining said head to a fixed orientation cross-wise to said axial direction; and

said rams being constrained to a single degree of freedom of motion in linear translation parallel to said axial direction between said stator and said head.

22. The two stage compressor feed apparatus of claim 21 wherein said rams, said head and said piston are slacklessly connected.

23. The two stage compressor feed apparatus of claim 21 wherein said rams include at least a first ram and a second ram, said first and second rams being mounted on substantially diametrically opposite sides of said second stage compressor piston.

24. The two stage compressor feed apparatus of claim 21 wherein said apparatus includes a controller and feedback sensors, said controller and feedback sensors being operable to co-ordinate motion of said first and second rams.

25. The two stage compressor feed apparatus of claim 24 wherein said controller has a pre-set schedule of displacement as a function of time for said rams and is operable to cause motion of said rams to conform to said schedule.

26. The two stage compressor feed apparatus of claim 24 wherein said first stage screw discharges to a chamber having a liquid extraction manifold and drain.

27. The two stage compressor feed apparatus of claim 24 wherein:

said first stage screw has a discharge tip, said discharge tip being surrounded by a sleeve;

said sleeve being an axially stationary sleeve;

said second stage piston surrounding said sleeve, and being axially reciprocable relative thereto;

said sleeve having an interior face oriented toward said screw; and

said interior face of said sleeve having axially extending reliefs defined therein.

28. The two stage compressor feed apparatus of claim 24 wherein said feed apparatus discharges to a downstream conduit, said downstream conduit includes a cooling jacket, and said cooling jacket includes at least one internal helical wall.

29. The two stage compressor feed apparatus of claim 24 wherein said feed apparatus includes a drive mounted to turn said screw of said first stage compressor, said drive being a variable speed drive, and said controller being operable to adjust drive speed of said screw in co-ordination with motion of said second stage compression piston.

30. The two stage compressor feed apparatus of claim 24 wherein said two stage compression chamber gives onto a discharge, and said apparatus includes a discharge cone for seating athwart said discharge in opposition to passage of feedstock, said cone being axially reciprocable to permit egress of feedstock from said discharge, said controller being operable to adjust position of said discharge cone in co-ordination with motion of said second stage compressor piston.

31. The two stage compressor feed apparatus of claim 24 wherein said first stage compressor screw includes a volute having a reducing pitch between successive turns of said volute.

32. The two stage compressor feed apparatus of claim 28 wherein said cooling jacket has an inwardly facing wall defining a discharge passageway of said second stage compressor, and said inwardly facing wall tapers outwardly in the direction of flow.

33. A process of compressing loose fibrous feedstock using a fibrous feedstock compression apparatus, said process comprising the steps of:

passing said feedstock through a first stage of compression;

employing a reciprocating piston to submit the feedstock to a second stage of compression, that reciprocating piston being mounted to a head, the head being mounted on an actuator, that second stage of compression including continuously sensing position of said actuator during operation thereof, and

continuously sensing and controlling motion of actuator and the first stage of compression.

34. The process of claim 33 wherein said process includes operating said actuator to a set schedule of displacement as a function of time.

35. The process of claim 33 wherein said process includes co-ordinating operation of said first stage of compression with operation of said actuator.

36. The process of claim 35 wherein said first stage of compression includes a screw compressor mounted to a variable speed drive, and said process includes continuous variation of the speed of said variable speed drive in co-ordination with operation of said actuator.

37. The process of claim 33 wherein said apparatus includes an axially movable discharge cone, and said process includes actively adjusting one of (a) position;

and (b) reactive force applied to said cone in co-ordination with motion of said second stage compressor piston.