 Metric Screw Pitch Gauge 60-Degree Range 0.5-7.0mm US $5.75 
|
 Measuring Tool 55 Degree Thread 20 Blades Screw Pitch Gage Gauge US $5.48
|
 Whitworth 4-62G Metric 0.25-6.0mm Screw Pitch Gauge US $10.09
|
 PROCUNIER L.H. 32 PITCH LEAD SCREW ASSEMBLY 1AL (g) US $99.95
|
 SCREW PITCH GAGE 4-84 ENGLISH NEW US $7.29
|
 Foldable 4-48 Inch 55 Degree Thread 20 Blades Screw Pitch Gauge US $5.26
|
 PROCUNIER R.H. 32 PITCH LEAD SCREW ASSEMBLY 1AL (i) US $99.95
|
 1pc 20 blades 55° Whitworth screw Thread Pitch Measure Gage US $4.99
|
 1pc 20 blades 60° Metric screw Thread pitch Measure Gage US $4.99
|
 1pc 55° Whitworth and 1pc 60° Metric screw Thread pitch Measure Gage US $7.99
|
 SHP NE60-SP51 - 4 TO 84 PITCH - 51 LEAVES - SCREW PITCH GAGE ~NEW~ US $16.00
|
 Screw Pitch Gage, 4 - 42 TPI and 0.4 - 7mm, 51 Leaves US $39.99
|
 MACHINIST MILL LATHE TOOL Starrett Screw Pitch Gage Number 155 in Box US $12.50
|
 STARRETT METRIC SCREW PITCH GAGE 156 M US $21.50
|
 Metric Whitworth Screw Pitch Gauge Measuring Tool US $10.24
|
 Starrett 585EP Screw Thread Micrometer 20-24 T.P.I. Range, 0.001" 1-2" Pitch Dia US $59.00
|
 BROWN&SHARPE "RADIUS GAUGE NO.627 B ALSO LUFKIN NO.73D "SCREW PITCH GAUGE US $9.99
|
 4-48 55 Degree Thread 20 Blades Screw Pitch Gage Gauge US $5.62
|
 Metric Whitworth Screw Pitch Gauge Measurement Tool US $10.24
|
 General Machinist Screw Pitch Gage, No. 251, Pitches 4 to 84, V-US Am Nat US $12.50
|
 Screw Pitch Gage 24 Leaves, 60 Degree Threads AGS1115 US $10.00
|
 NSK CNC BALL SCREW & NUT,40MM DIA X .75 PITCH,44.5" O/L US $250.00
|
 NSK CNC BALL SCREW & NUT,40MM DIA X .75 PITCH,35" O/L US $200.00
|
 Metric 0.25-2.50mm Screw Pitch Gage US $7.00
|
 THREAD/SCREW PITCH GAUGE US $14.50
|
 Brown & Sharpe Screw Pitch Gage 633 Machinist Lathe Mechanical US $29.95
|
 Measuring Range 0.5-7.0mm Metric Screw Pitch Gauge US $5.75
|
 Vintage Starrett No. 474 Screw Pitch Gage 4 to 80 v thread 28 pitches US $6.50
|
 Procunier Lead Screw Assembly, 80 Pitch, X-456 US $149.99
|
 FEELER GAGES - RADIUS GAGES – SCREW PITCH GAGES – LOT of 5 US $9.00
|
 4-42 SCREW PITCH GAGE US STANDARD 60° #EG07-5642 US $11.75
|
 0.4 - 0.7 mm SCREW PITCH GAGE METRIC 60° # EG06-0321 US $11.75
|
 Starrett Screw Thread Pitch Micrometer 2-3" 4.5 - 6 tpi US $199.99
|
 Starrett Screw Thread Pitch Micrometer 2-3" 10 - 13 tpi US $219.99
|
 SCREW PITCH GAGE 30 BLADES STD-V-THD US 4-42 US $18.99
|
 Metric Micrometers Screw Pitch & Thickness Gauges In Original Boxes US $29.00
|
 ENGLISH METRIC SCREW PITCH GAGE 4-56" 0.5-6MM 28 BLADES US $7.00
|
 MIT BALL SCREW, AUTO PITCH, GANG P E818-212-089 US $72.90
|
 5/8 DIA, 5 PITCH X 10.37 CNC BALL SCREW,SUPERIOR ELECTRIC SLO-SYN STEPPING MOTOR US $250.00
|
 Screw Pitch Gage 4-42 TPI, 28 Leaves, 60 Degree Threads AGS1114 US $12.99
|
 Vermont American 21938 Metric Screw Pitch Gauge 0.45mm to 2.50mm FREE SHIPPING US $13.99
|
 Metric Screw Thread Pitch Gage from .025 mm to 2 mm---27 sizes- Machining Auto US $17.00
|
 PROCUNIER 1.25MM PITCH TAPPING LEAD SCREW ASSEMBLY L.H US $59.00
|
 Thread Craft 40mm Dia x 10mm Pitch Ball Screw US $1,110.00
|
 Thread Craft 2.00 in Dia x 0.20 in Pitch Ball Screw US $1,650.00
|
 Motch 1.57 Dia x 0.20 Pitch Ball Screw US $810.00
|
 SKF 1.50 in Dia x 0.25 in Pitch Ball Screw US $390.00
|
 Steinmeyer 32mm Dia x 5mm Pitch Ball Screw US $525.00
|
 Cincinnati 2.25 in Dia x 0.50 in Pitch Ball Screw US $570.00
|
 Cincinnati 1.50 in Dia x 0.40 in Pitch Ball Screw US $510.00
|
 Range 0.5-7.0mm Metric Screw Pitch Gauge 60 Degree US $4.18
|
 Starrett Screw Pitch Gage No. 6 US $15.00
|
 PET #5628 RADIUS SCREW PITCH GAGE MACHINIST NICE US $12.99
|
 Starrett no. 155 English Screw Pitch Gauge 27 Leaves US $39.00
|
 Whitworth and Metric Screw Thread Pitch Measure Gage US $20.00
|
 Portable 4-48 Inch 20 Blades 55 Degree Thread Screw Pitch Gauge US $5.49
|
 Hanson Gauge Screw Pitch 12018 US $5.99
|
 ENGLISH SCREW PITCH GAGE 4- 84" US 60° THREAD 51 BLADES US $9.90
|
 (5) COMMANDER TAPPING DRILL HEAD PITCH LEAD SCREWS - MULTI DRILL PRESS PROCUNIER US $49.99
|
 NEW CNC 1" DIA BALLSCREW 3/8" PITCH (LEAD) 34-1/4 LONG US $99.99
|
 Screw Pitch Gage ACME29 Degree Angle 1N-12N 16 Blades US $9.07
|
 General Tools #252mm Screw Pitch Gage (9 to 40) US $24.97
|
 Metric Screw Pitch Gauge 789865 Measures 0.45 to 2.50 mm Range US $8.99
|
 3/4"OD X 10 PITCH BALL SCREW SLIDE ASSEMBLY 15" THREADED 18" LINER SLIDE US $99.99
|
 (2) Starrett Pitch Diameter Screw Thread Micrometers 585 4½-7P & 585B 8-13P US $89.95
|
Screw Pitch
Bolts Nuts Screws Bolt Thread Pitch, Length and Bolt Diameter
Background of twin screw extruder
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a twin screw extruder comprising a casing with a working direction; two partially intersecting casing bores, which are parallel to each other; two shafts, which are disposed in the casing bores and which are drivable to rotate in the same direction of rotation about an axis of rotation, the axes of rotation having a distance A from each other; and single-flight kneading disks, which are fixed on the shafts and have surface lines extending parallel to the respective axis of rotation, the kneading disks, in a cross-section perpendicular to the axis of rotation, comprising a crest, which is formed as a segment of a circle about the respective axis of rotation and which has a crest angle b and a radius RA ; a bottom, which is formed as a segment of a circle about the respective axis of rotation and has a bottom angle g and a radius RI ; two flanks, which join the crest and the bottom; RA >RI und A≅RA RI applying.
2. Background Art
Single-flight kneading disks are known from DE 813 154 B. They have a crest angle greater than 90° , in this regard possessing a comparatively important cross-sectional surface. The kneading disks wipe the casing as well as themselves. In these known kneading disk arrangements, no overall conveyance of the treated material takes place in or against the operating direction of an extruder which lodges the kneading disks. The mixing effect by this type of kneading disks is low. The same is true for the kneading effect. Furthermore, also the free cross-sectional surface is defined and thus the mean dwell time, within a lengthwise section of the extruder, of the material to be treated.
U.S. Pat. No. 5,573,332 teaches a screw element for a screw-type extrusion machine. The screw elements are helical and have varying pitch directions. Lengthwise mixing is obtained by the screwing in opposite directions, whereas crosswise mixing is attained by the elongated wedge of the flank arc. This crosswise flow is a typical continuous shear flow, which is primarily a dispersive mixing operation. Dividing the flow into various partial flows, recirculation and offset combination thereof do not take place, which is why the distributive mix is not optimal.
DE 43 38 795 C teaches a continuously working multi-screw extruding machine for masses to be plastified. Provided between two closely intermeshing conveying screws and a dam-up element is a screw which conveys forwards and adjacent thereto a non-intermeshing screw which conveys backwards. A drawback resides in that the wall of the casing cannot be scraped off, since the screws have a diameter that corresponds to half the center distance. This does not prevent the material to be treated from sticking on the casing wall. Since the casing wall is not wiped, this results in very bad heat transmission. In the case of high differences of temperature between the casing wall and the product, this will result in important inhomogeneities of temperature which will moreover negatively affect the material to be treated.
SUMMARY OF THE INVENTION
It is an object of the invention to improve a twin-screw extruder of the generic type such that given a minimal energy input and high dwell time, the entire material to be mixed is completely distributively mixed and simultaneously the casing wall is entirely wiped.
This object is attained by 0°≤b≤45° applying to the crest angle b. The gist of the invention resides in providing cylindrical kneading disks--i.e. kneading disks having surface lines extending parallel to their respective axis--with a very small crest angle. This reduces the energy input and helps obtain mixing of the entire volume. Furthermore, complete scraping of the walls of the casing bores is ensured, i.e. there is no sticking, and good heat transmission is ensured. The wedge flows along the flanks of the kneading disks prevent neutral zones of reduced mixing to originate. The intermeshing action of the kneading disks ensures intense mixing of the material to be treated. The kneading disks wipe each other at least partially. Given a constant diameter of the casing bores, the free cross-sectional area available to the material to be treated is increased, as a result of which the throughput can be raised.
The extruder, in which the kneading disks of at least one shaft are offset in the working direction by an offset angle e in the direction of rotation for conveyance against the working direction, 0°>|e|>180° applying, has the advantage of return conveying being attained, which strongly increases the dwell times.
The arrangement, according to which the kneading disks of one shaft are offset in the working direction against the direction of rotation by an offset angle |e|>180° and the kneading disks of the other shaft are offset in the working direction in the direction of rotation by an offset angle |e|>180° , has the advantage that especially intense mixing is attained through a circulating way of conveyance.
Additional advantages and features of the invention will become apparent from the ensuing description of an exemplary embodiment, taken in conjunction with the drawing.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a diagrammatic illustration of a lateral longitudinal view of a twin screw extruder;
FIG. 2 is a cross-section through the extruder on the line II--II of FIG. 1 with the illustration of two kneading disks according to the invention;
FIG. 3a) to h) are cross-sections according to FIG. 2 at varying moments in a chronological sequence with an addendum modification angle z=0°;
FIG. 4a) to h) are illustrations as in FIG. 3 with an addendum modification angle z=45°;
FIG. 5a) to h) are illustrations as in FIG. 3 with an addendum modification angle z=90°;
FIG. 6 is an illustration as in FIG. 2 with kneading disks arranged to be offset successively; and
FIG. 7 is a partial longitudinal section through the extruder on the line VII--VII of FIG. 1.
About the Author
The invention relates to a twin screw extruder comprising a casing with a working direction; two partially intersecting casing bores, which are parallel to each other; two shafts, which are disposed in the casing bores and which are drivable to rotate in the same direction of rotation about an axis of rotation, the axes of rotation having a distance A from each other;
Here are a list of other products on Woodturning Tools, come check these out:
