Post on 08-Jun-2020
transcript
CENERG GLOBAL TOOLS PVT. LTD.
PLOT# 62,EPIP
PASHAMYLARAM, MEDAK DISTRICT
ANDHRA PRADESH, INDIA 502307
PHONE +91 8455 – 223594
+91 8455 – 223596
+91 8455 – 223597
FAX +91 8455 – 223594WEB www.cenerg.in
EMAIL info@cenerg.in Rotary Drill Bits
CENERGG L O B A L + T O O L S
At CENERG GLOBAL TOOLS we offer an extensive line
of Rotary Drill Bits with reliable tool life and
performance that improves productivity and optimizes
drilling cost.
We have a state of the art manufacturing facility in
Hyderabad, India managed by a team of highly
experienced Engineers. The manufacturing facility is
equipped with latest CNC Machines, fully automated
Heat Treatment furnaces, sophisticated Metallurgical
Labs with all Inspection & Testing facil it ies.
The production process is closely monitored and
controlled at every stage of the manufacturing process
with ability to produce 18,000 rotary bits per year.
Our range of Rotary Drill Bits cover Blasthole,
WaterWell , Construction, Oi lfield, Workover,
Exploration and Directional Drilling applications.
The size ranges from 2 �⁄�” (60mm) – 12 ¼” (311mm)
in Steel Tooth and Tungsten Carbide Insert Bits.
Today Customer’s unique drilling challenges call for
special solutions and Cenerg is well equipped to
respond to these challenges and adapt its wide range of
products to provide customized solutions to best suit
the specific needs.
Bearing Types
Open Air bearing
Open Fluid bearing
Sealed Roller bearing
Sealed Journal bearing
Bit Features / Enhancements
Open Air to Bearing Bits
Sealed Bearing Bits
IADC classification
Product offering
Useful Operating Information
Table of contents
Bearing Types….
Sealed Roller Bearing
While sealed Roller Bearings have some of the features of Open
to Air Bearings, the Bearing pack is protected with an O- Ring
Seal and has lubrication and pressure compensator system built
in. This prevents ingress of dirt into the Bearing system and
leakage of grease. This configuration is used for Mining,
Workover and Exploration applications
Sealed Journal Bearing
In Sealed Journal Bearing the Rollers inside the cone are replaced
by a Floating Bush made out of special alloys which is silver plated.
The Bearing Pack is protected with an O-Ring Seal. The Bearing
lubrication and pressure compensator system is built in. The
Floating Bush is highly resistant to heat and galling.
Consequently these Bearings are very durable and
suitable for Oil & Gas as well as Horizontal and
Directional Drilling applications
In Bearings for Small Diameter Bits instead of the Floating Bush
the internal surface of the Cone is silver plated using a special
process. This design enables Bearing size to be increased in
relation to the diameter of the Bit enhancing its durability. This
Bearing design finds application in Exploration and
Workover and Well drilling applications
Bearing Types & Valves
Non Return Valves
The non return valve is designed to work very effectively in heavy
ground water conditions protecting both the bit’s bearings as well
as the pipe threads.
Open Air Bearing
Open Fluid Bearing
In this configuration an air passage is provided to the Bearing area.
The compressed air cools and lubricates the Bearings and blows
away any drilling debris extending the life of the Bearing. This
Bearing configuration is commonly used in Blasthole Mining
applications
The standard open roller bearings are without a seal or an air
passage. They are ideal for drilling shallow holes, in the hundreds
of feet with either foam or mud circulation. These bearing
configurations are commonly used in Water Well applications.
Air to Bearing Bit features …
Special features provided for
cone steel erosion when
drilling is abrasive formations
The cutting structure on the bits is
optimized with intermittent pitch
breaks for efficient rock breakage
and to reduce vibration
** Customizable gage
protection options for
maximum endurance
**Customizable shirttail
protection options for
maximum endurance
A variety of hole bottom
cleaning options depending
on the application
Non return valve options for water
injection drilling and heavy ground
water conditions.
The tooth are long, strong, widely
spaced with intermittent deletions
to permit deep penetration in the
formation with comparatively light
weight on bit Hard metal deposit on
the teeth for endurance
and shape retention
Grease compensator
to maintain pressure
inside the bearing and
improve lubrication
Nozzles with Threaded
and Nail retention
options depending on
the application
Special carbide protection
available on nozzle boss
while drilling deep holes
Sealed Bearing Bit features …
API standard threads are turned
with precision machining making
them concentric to the gage
rows for uniform loading on
bearings
Additional product features…
Cone steel protection options
Shirttail protection options
Gage protection options
Small carbide inserts in between gage
and drive rows to reduce steel wear and
increase service life
Hard metal on nose area of
cones to avoid coring while
drilling is very hard and
abrasive formations
Single gage protection for normal
non-abrasive drilling conditions
1/3rd shirttail protection
for non abrasive drilling
2/3rd shirttail protection for
medium hard and
moderately abrasive drillingFull shirttail protection for
very hard and very abrasive drilling
Double gage protection for very
abrasive drilling conditions
Types of Bits….TC Insert
Soft formation
Hard formation
Medium formation
Application : For use in less abrasive softer formations with compressive strength ranging between 90 – 150 Mpa, such as shales, limestones, carbonates and most metamorphic formations.
Cutting profile: These bits are characterized by large diameter, widely spaced chisel or sharp conical inserts with high projection. This configuration promotes maximum penetration rates in softer formations. Smaller carbide inserts are provided on the gage and inner rows to contain shell erosion and improve performance
CN4X series
CN40 CN43
Application : For use in moderately abrasive consolidated formations with compressive strength ranging between 120 – 200 Mpa such as hard limestone, quartzite, granodiorite, and medium grade metamorphic formations.
Cutting profile: These bits are characterized by moderately spaced wedge chisel or conical inserts with medium projection. This configuration promotes good penetration rates in medium hard and moderately abrasive formations. Smaller carbide inserts are provided on the gage and inner rows or hard metal is deposited in the nose area to contain shell erosion and improve performance
CN50
CN5X & CN6X series
CN7X series
Application : For use in abrasive consolidated formations
with compressive strength above 200 Mpa such as
taconite, quartzite and banded iron formations
Cutting profile: These bits are characterized by closely
spaced conical or spherical inserts with medium to low
projection. This configuration promotes good penetration
rates in hard, consolidated and very abrasive formations.
Smaller carbide inserts are provided on the gage and inner
rows or hard metal is deposited in the nose area to contain
shell erosion and improve performance
CN71 CN73
CN60
Types of Bits….Steel Tooth
Soft & Medium formation
Hole bottom flushing options
Hard formation
Application : These tooth bits are designed for optimum
performance in formations of low compressive strength
ranging below 70 MPA
Cutting profile: These soft formation bits are designed
with long, slim, strong, widely spaced teeth with
intermittent deletions to permit deep penetration in the
formation with comparatively light weight on bit.
CN1X & CN2X series
CN11 CN22
Application : These tooth bits are designed for medium to
hard formations with compressive strength ranging
between 70 - 100 MPA
Cutting profile: These bits have higher capacity bearings,
more closely spaced teeth with increased tooth angles and
more gage surface for resisting wear to allow the use of
heavier weights required to effectively drill hard formations
CN33
CN3X series
Side Jet Center jet Combined jet
Product Line
Open Bearing
Air Circulation Fluid Circulation Roller Journal Plated
Sealed Bearing
TC Series5�⁄�"-12�⁄�"
TC Series21�⁄�"-12�⁄�"
ST Series3"-7�⁄�"
ST Series2�⁄�"-7�⁄�"
TC Series7�⁄�"-10�⁄�"
TC Series5�⁄�"-6�⁄�"
TC Series2��⁄��"
ST Series ST Series3�⁄�"-6�⁄�" 3�⁄�"-4�⁄�"
Strength of Rock Soft Medium Hard
PSI MPA 10 20 30 40 50 60 70 80
Lower Lower Limestone, Siltstone
2,000 14 Claystone, Mudstone, schist
4,000 28 Marl, Chalky Limestone
6,000 41 Soft - Medium Shales
8,000 55 Soft Marble, Dolomite
10,000 69 Consolidates Sandstone
12,000 83 Medium Shale, conglomaerate
14,000 97 Tuff, Soft Schist
16,000 110 Andesite, Rhyolite
18,000 124 Quartzite (Sand & Silt)
20,000 138 Limestone, Marble
22,000 152 Monzonite, Granite
24,000 165 Gneiss
26,000 179 Diorite, Diabase
28,000 193 Hard Shale, Slate
30,000 207 Limestone, Dolomite
32,000 221 Basalt
34,000 234 Tactite, Skarn
36,000 248 Granodiorite
38,000 262 Taconite
40,000 276 Quartzite
42,000 290 Syenite
44,000 303 Gabbro
46,000 317
48,000 331 Banded Iron
50,000 345 Taconite
52,000 359 Chert
54,000 372 Basalt (Hard)
56,000 386 Quartzite
58,000 400
60,000 414 Amphibolite
Higher Higher Hornfels, Hematite Ore
Rock Formation / Class
Bit selection chart
Blasthole Bits
4-1 4-2 4-3 4-4 5-1 5-2 5-3 5-4 6-1 6-2 6-3 6-4 7-1 7-2 7-3 7-45�⁄�" CN52 CN62 CN72
150 mm
6�⁄�"CN52
CN52
CN62
CN62CN62
CN72
CN72
159 mm
6�⁄�"172 mm
CN42 CN64
7�⁄�"200 mm
CN42CN40 CN50 CN53 CN60 CN70
8�⁄�"219 mm
CN50 CN53
CN53
CN60 CN70CN64
CN64
9"229 mm
CN42CN40 CN50 CN60 CN70
CN50 CN60
CN42SCN40S
CN42CN409�⁄�"
251 mm
CN43 CN50 CN63 CN73
CN73
CN64CN42 CN50
CN42S
CN42CN4010�⁄�"
270 mm
CN63
BitDiameter
Softest Rock hardness Hardest
Sealed bearing Bits
2 ��⁄��" 75 mm
3 �⁄�" 99 mm
4 �⁄�" 114 mm
4 �⁄�" 121 mm
5 �⁄�" 140 mm
6"
152 mm
6 �⁄�"
159 mm
6 �⁄�"
165 mm
Bit Diameter10 20 30 40 50 60 70
CN11J
CN21J
CN21P
CN21J
CN21P
CN31P
CN31J
CN31J
CN31P
CN31J
CN52P
CN52J
CN52J
CN54J
Steel tooth Tungsten carbide
Product offering
12�⁄�"311 mm
CN53 CN73CN63
Water-well, Construction & Exploration Bits
Inches
2 �⁄�"
2 �⁄�"
2 �⁄�"
2 ��⁄��"
3"
3 �⁄�"
3 �⁄�"
3 �⁄�"
3 �⁄�"
3 �⁄�"
3 �⁄�"
3 �⁄�"
4"
4 �⁄�"
4 �⁄�"
4 �⁄�"
4 �⁄�"
4 �⁄�"
4 �⁄�"
4 �⁄�"
5"
5 �⁄�"
5 �⁄�"
5 �⁄�"
5 �⁄�"
5 �⁄�"
5 �⁄�"
5 �⁄�"
6"
6 �⁄�"
6 �⁄�"
6 �⁄�"
6 �⁄�"
6 �⁄�"
7"
7 �⁄�"
mm.
64
67
73
75
76
80
83
86
89
92
95
99
102
105
108
111
114
118
121
124
127
130
133
137
140
143
146
149
152
156
159
162
165
172
178
194
10
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
CN11
20
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN23
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
CN32
30
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN33
CN42
CN42
40 50 60 70
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN52
CN62
CN62
CN62
CN62
CN62
CN62
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
CN72
Bit Diameter Steel tooth Tungsten carbide
Product offering
Blasthole Bits
Water-well, Construction & Exploration Bits
Product specifications
Sealed Bits
BitDiameter
5 �⁄�"150 mm
6 �⁄�"159 mm
6 �⁄�"172 mm
7 �⁄�"200 mm
8 �⁄�"219 mm
9"229 mm
9 �⁄�"251 mm
10 �⁄�"270 mm
Pin connection
Productweight
Flushmode
3 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
4 �⁄�" API REG
4 �⁄�" API REG
4 �⁄�" API REG
6 �⁄�" API REG
6 �⁄�" API REG
12 Kg
14.5 Kg
17.5 Kg
28 Kg
42 Kg
44 Kg
57 Kg
65 Kg
Jet
Jet
Jet
Jet
Jet
Jet
Jet
Jet
BitDiameter
Pin connection
Productweight
Flushmode
2 ��⁄��"75 mm
3 �⁄�"99 mm
4 �⁄�"114 mm
4 �⁄�"121 mm
5 �⁄�"140 mm
6"152 mm
6 �⁄�"159 mm
6 �⁄�"165 mm
N-rod thread
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
2 Kg
4 Kg
5.5 Kg
8.5 Kg
11 Kg
12 Kg
13.5 Kg
16 Kg
Center Flush
Center Flush
Jet flush
Jet flush
Jet flush
Jet flush
Jet flush
Jet flush
BitDiameter
2 �⁄�"64 mm
2 �⁄�67 mm
2 �⁄�"73 mm2 ��⁄��"75 mm
3"76 mm3 �⁄�"
80 mm3 �⁄�"
83 mm
3 �⁄�"86 mm3 �⁄�"
89 mm3 �⁄�"
92 mm3 �⁄�"
95 mm3 �⁄�"
99 mm4"
102 mm4 �⁄�"
105 mm4 �⁄�"
108 mm4 �⁄�"
111 mm4 �⁄�"
114 mm4 �⁄�"
118 mm
Pin connection
Productweight
Flushmode
N-rod thread
N-rod thread
N-rod thread
N-rod thread
N-rod thread
N-rod thread
N-rod thread
N-rod thread
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
1.7 kg
1.6 Kg
1.5 Kg
2 kg
2 kg
2 kg
2 kg
2 kg
3.2 Kg
3.2 Kg
3.5 Kg
4 Kg
4 Kg
4 Kg
4 Kg
4 Kg
5.5 Kg
6 Kg
Center
Center
Center
Center
Center
Center
Center
Center
Center
Center
Center
Center
Center
Center
Center
Center
Center
Center
BitDiameter
Pin connection
Productweight
Flushmode
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
2 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
3 �⁄�" API REG
4 �⁄�" API REG
8.5 kg
8.5 kg
8.5 kg
10 Kg
10 Kg
10.5 Kg
11 Kg
11.5 Kg
11.9 Kg
12 Kg
12 Kg
12.5 Kg
13.5 Kg
16 Kg
16 Kg
16 Kg
17 Kg
24 Kg
Center
Center
Center
Center
Center
Center
Center
Center
Center
Center / Jet
Center / Jet
Center / Jet
Center / Jet
Center / Jet
Center / Jet
Center / Jet
Center / Jet
Center / Jet
4 �⁄�"121 mm
4 �⁄�"124 mm
5" 127 mm
5 �⁄�"130 mm
5 �⁄�"133 mm
5 �⁄�"137 mm
5 �⁄�"140 mm
5 �⁄�"143 mm
5 �⁄�"146 mm
5 �⁄�"149 mm
6" 152 mm
6 �⁄�"156 mm
6 �⁄�"159 mm
6 �⁄�"162 mm
6 �⁄�"165 mm
6 �⁄�"172 mm
7"178 mm
7 �⁄�"194 mm
Standard Operating Practices
When a new bit is installed, drill at reduced weight for a short period
Provide adequate air to the bit to ensure trouble free bearing performance and
reduced abrasion wear on cones and shirttails. (recommended is 40 – 45 psi at the
bit)
Turn the air on before lowering the bit to collar the hole. Keep the air on until the bit
is finished drilling and is out of the hole.
Always rotate the bit when moving in or out of the hole.
Some indications that the hole is not being properly cleaned are:
- Increase in torque indication through higher hydraulic pressure.
- Increase in air pressure.
- Heavy wear and /or damage indications on shirttails.
Always rotate when coming out of the hole to:
- Help in cleaning the cuttings from the hole.
- Keeps cuttings from entering the bearings around the back face of the cone.
Never use the hydraulic pressure on the bit for levelling the machine.
When adding extra drill steel in wet holes, always make three or four cleaning
passes to get a cleaner hole bottom.
Bit cones should be checked periodically to be sure that all are about the same
temperature. One hot cone generally indicates that the air passage to that bearing
is obstructed. Clean the bit with water and continue drilling
A bit should never be left down the hole when repairs require lowering the head
assembly to the deck. This bit should be substituted by a dull bit to protect the drill
pipe threads.
Properly maintain the drill pipe and its threaded connections. A bent pipe will
often cause early failure.
Blasthole bits drill most economically when sufficient weight is applied to cause
spalling of the formation. Selecting correct rotary speed is usually a matter of trial-
and-error, depending upon the formation being drilled or use the factory
recommended weight and rotation speeds.
Always record footage drilled, time in the hole, RPM, WOB (weight on bit), air
pressure psi, formation drilled and any unusual drilling conditions.
After the bit is discarded it is necessary to make a comparative analysis of each bit
type dulling and causes. Evaluating those findings can increase drilling efficiency
while reducing drilling cost and will precisely determine what bit design features
are required for the application.
Pull Down & Rotation
Rotation is required to move the cutting teeth to the next rock cutting position. The faster
you move the teeth to the next position, the faster you will drill. If the rock resists indentation
by the teeth, there will be minimal rock breakage, and rate of penetration will not increase
proportionally with higher rotation.
For softer rock high RPM is required as Soft rock responds to frequency and for harder rock
low RPM is required as Hard rock responds to time
140
120
100
80
60
40
20
0
5,00
0
10,000
15,000
20,000
25,000
30,000
35,000
40,000
45,000
50,000
Rock strength UCS - psi
RPM
Bit
RP
M
5,00
0
0,00
0
15,000
20,000
25,000
30,000
35,000
40,000
45,000
50,000
Pull down
Pu
ll d
ow
n
lb/i
nch
of
bit
dia
.
10,000
8,000
6,000
4,000
2,000
0
Rock strength UCS - psi
Pull down load is required to adequately push teeth into the rock to break in efficiently. It is
the primary factor in rate of penetration. The unconfined compressive strength of the rock
determines how much pull down is to be applied.
High UCS rocks may need time for the indenter to break it. Lower RPM is often required for
efficient rock breakage.
Air Requirements
In rotary blasthole drilling, delivery of air in sufficient volume and at
proper pressure is very essential to assure optimum bit performance.
Right amount of air ensures efficient cuttings removal from the
hole bottom to the surface. It also reduces the cutting structure
wear and bearing erosive wear by means of efficient bottom hole
cleaning.
The right amount of back pressure is also required to cool the
bearing and to keep the bearing clean from drilling debris.
The air volume provided must be good enough to produce a bailing
velocity of 5,000-7,000 ft./min. for dry cuttings; and 7,000-10,000
ft./min. for wet cuttings.
To determine volumetric requirements, and bailing velocity the
simple equation may be used.
2 2 Q = V/183.35 (D – d )
Q = cubic feet per minute of free air.
V = Annular Velocity feet / min
d = drill pipe outside diameter, inches.
D = hole diameter, inches.
183.35 = Factor for conversion
Hence to determine the bailing velocity the equations is
2 V = Q x 183.35 / (D²- d ) feet per min
Nozzle selection
Nozzles should be selected so that the pressure inside the bit is 40-
45 psi. The cab operating pressure inside the drills cabin could be
higher, depending on the type of drill and CFM of air circulated.
Typically, on compressors rated with 80-100 psi bit pressures can be
10 - 25 psi lower than the cab gauge reading.
Nozzle Selection Table Notes
12 �
⁄�"
to
15"
8 m
m
10 m
m
11 m
m
12.7
mm
14 m
m
8 m
m
10 m
m
11 m
m
12.7
mm
14 m
m
10 m
m
11 m
m
12.7
mm
14 m
m
16 m
m
17.5
mm
19 m
m
10 m
m
11 m
m
12.7
mm
14 m
m
16 m
m
17.5
mm
19 m
m
22 m
m
25 m
m
10 m
m
11 m
m
12.7
mm
14 m
m
16 m
m
17.5
mm
19 m
m
22 m
m
25 m
m
Th
read
con
nect
ion
2 �
⁄�"
&3 �
⁄�"
3 �
⁄�"
4 �
⁄�"
6 �
⁄�"
6 �
⁄�"
Bit
Dia
mete
r
5"-
6"
6 �
⁄�"
to
7 �
⁄�"
7 �
⁄�"
to 9"
9 �
⁄�"
to 11"
No
zzle
siz
e
NO
ZZ
LE S
ELE
CT
ION
Air
Pre
ssu
re d
rop
acr
oss
Bla
st-h
ole
bit
s w
ith
vari
ou
s n
ozz
le s
ize. A
ir v
olu
me d
eliv
ere
d -
CFM
(cu
bic
feet
per
min
ute
)
500
62
47
35
26
18
52
43
34
29
23
35
29
22
35
28
20
600
77
59
45
34
24
62
51
41
33
29
44
36
26
21
45
36
26
21
18
700
71
55
42
31
72
61
48
41
34
54
43
32
27
20
53
43
32
27
18
24
19
800
66
50
38
81
69
57
48
41
65
50
38
33
25
22
61
51
38
33
24
21
29
24
20
900
75
58
44
78
65
54
47
74
56
44
38
30
26
20
69
59
44
39
31
25
18
34
28
22
20
1000
66
58
73
61
51
82
64
50
44
35
30
24
76
66
52
44
35
30
21
40
34
26
23
1100
74
58
79
67
56
70
58
50
41
35
28
73
59
50
40
35
25
21
45
39
30
26
19
1200
64
73
62
76
66
56
46
40
33
80
65
55
47
38
32
23
52
44
33
28
22
20
1300
71
79
67
82
75
62
51
45
36
70
59
48
44
35
27
57
48
37
32
25
23
16
1400
73
83
68
56
51
40
76
65
52
48
39
31
20
62
53
41
35
28
26
18
1500
79
74
64
56
46
67
59
50
44
31
22
68
57
45
39
31
29
20
1600
81
68
61
50
74
61
55
46
36
22
74
61
49
43
34
32
22
1700
72
66
54
79
65
59
49
39
24
66
54
47
38
35
24
1800
78
72
59
69
63
53
42
27
71
58
50
41
38
26
18
1900
78
64
73
67
56
45
29
76
62
54
44
41
27
20
2000
69
77
71
60
47
32
66
58
47
43
29
22
2100
74
75
63
50
34
71
62
51
46
32
24
16
2200
78
79
67
53
37
65
54
49
34
26
18
2300
72
54
39
69
57
52
36
28
20
2400
74
60
41
73
61
54
39
30
24
2600
78
64
46
65
58
41
34
26
2800
70
51
69
52
43
38
28
3000
76
56
66
46
42
30