2.5.1 Basics of the Screw Compressor
The screw compressor is a positive displacement rotary compressor. As shown in Figure 2-3 Compressor Mechanism, the refrigerant (gas) is continuously compressed by changing the volume between the casing and the male and female meshed screw rotors, which have different profiles. The rotor with 4 protruding lobe sections is called the M rotor (male rotor), and the rotor with 6 lobe depressions is called the F rotor (female rotor). Throughout this manual they are referred to as the M rotor and F rotor. The compressor M rotor shaft is driven by the two-pole or four-pole motor via the speed increaser gear.

2.5.2 Suction Process
As shown in Figure 2-4 Suction Process, the rotors’ different profiles mesh together. Also the volume enclosed between the M and F rotor lobes and compressor casing increases from the suction side as the rotors turn. As rotations continue, at a certain point the volume reaches its maximum, the rotors start to trap the gas between the lobes and compressor casing thereby isolating the gas from the suction port.

Figure 2-4 Suction Process
2202L5JE-DA-C5-N_2015.05.2 Compressor Specifications and Structure Compound 2-stage Screw Compressor 2.5 Mechanisms 1612LSC Speed Increaser Type 2-7

2.5.3 Compression Process
As the rotors further rotate, the sealing line between them moves toward the discharge side and the volume between the rotor lobes decreases and compresses the trapped gas. Figure 2-5 Compression Process Figure 2-6 Discharge Process

2.5.4 Discharge Process
Through the compression process, the volume between rotor lobes decreases to a predetermined value at the discharge port. Following rotor rotation, the compressed refrigerant gas is pushed out of the discharge port.

2.5.5 About Volume Ratio (Vi)
Volume ratios (Vi) of C-series screw compressors are indicated in performance tables or catalogs by using port symbols L and M. The volume ratio represented by each symbol is as follows: L=2.63, M=3.65.
Which volume ratio (L or M) should be used is decided according to operating conditions. If the compressor is used with a volume ratio that does not match operating conditions, operation will go inefficiently wasting the power. The relationship between volume ratios and generally used compression ratios is as follows: (Vi) κ= πi = Pd/Ps κ= Cp/Cv of refrigerant gas Vi = designed volume ratio πi = designed compression ratio The constant of the refrigerant gas also a factor, and the Vi value for the compression ratio will change according to the refrigerant gas used.

Figure 2-7 Volume Ratio Explanation
2202L5JE-DA-C5-N_2015.05.2 Compressor Specifications and Structure Compound 2-stage Screw Compressor 2.5 Mechanisms 1612LSC Speed Increaser Type 2-8
(A) When Vi matches operation conditions The required compression ratio and Vi are both low The required compression ratio and Vi are both high
(B) When Vi does not match operation conditions Vi is too low compared to the required compression ratio Vi is too high compared to the required compression ratio Figure 2-8 Relationship between volume ratio (Vi) and operation conditions 2202L5JE-DA-C5-N_2015.05.2 Compressor Specifications and Structure Compound 2-stage Screw Compressor 2.5 Mechanisms 1612LSC Speed Increaser Type 2-9

2.5.6 Capacity Control Mechanism
The capacity control structure involves the moving of a slide valve, bypassing suction gas just before compression on the suction side, which shortens the portion of the rotor used for compression. The slide valve is at the bottom of the casing where the rotors mesh together, and is constructed to move parallel to the rotor’s axis. This movement is changed by a cam mechanism into rotation movement, and as the position (capacity control ratio) is indicated externally, the electrical resistance value changes to provide feedback to the automatic control circuit.

Figure 2-9 Capacity Control Mechanism
The 1612LSC speed increaser type has capacity control on the low-stage block only. 2.5.7 Bearings and Balance Piston For the load created on the rotor perpendicular to the axle, a white metal-lined sleeve-type bearing is used. The bearing uses surface fitted ball bearings with angular contact for loads along the axis direction. In particular, axial load for the M rotor, which has one type of helical gear, is comparatively larger than that of the F rotor because of the thrust load from discharge pressure. This load for the M rotor is reduced by the use of a thrust bearing, along with a balance piston providing opposing hydraulic pressure.

2.5.8 Shaft Seal
To prevent refrigerant gas and oil leakage, a reliable mechanical seal assembly is used for the shaft seal of the speed increaser gear spindle. Mechanical seal assembly is mainly composed of "rotating ring" installed on the rotor shaft and "stationary ring" installed in the seal cover. Rotating ring rotates with the shaft, and slides each other with the stationary ring while maintaining a micron class gap. The sliding each other place is called as the sliding surface. As an example, for the BBSE (Balanced Bellows Single Seal)-type, which is a standard seal currently in use, the fixed ring (mating ring) is cast iron, and the rotating ring is carbon, with an O-ring for the packing.

Figure 2-10 Slide Valve in the
Rotor Casing 2202L5JE-DA-C5-N_2015.05. 2 Compressor Specifications and Structure Compound 2-stage Screw Compressor 2.6 Gas and Oil Flow 1612LSC Speed Increaser Type 2-10 2.6 Gas and Oil Flow The screw compressor’s compression process is described earlier in this manual. Gas for the compound speed increaser type 1612LSC compressor passes from the evaporator and through the suction strainer and check valve, and is sucked into the center part of the compressor ①, and it is compressed at the low-stage ② .Then the compressed gas is discharged at ③. ③ and ④ are connected by piping through which gas used for super cooling is mixed in from the liquid cooler. Lubricating oil injected at the low-stage is, while kept mixed with gas, suctioned from ④ into the high-stage. After being compressed at ⑤, the gas mixed with lubricating oil is discharged from ⑥ to the oil separator, and then sent to the condenser. The oil is cooled even without intermediate gas cooling, so the high-stage discharge temperature can be maintained at below 90 °C. Oil Supply Route Lubricating oil is split into 4 flows as shown in Figure 2-12, and after providing lubrication, it is mixed with discharge gas and leaves the compressor. In standard configurations, oil injection is not performed at the high-stage.

 

5.2 Maintenance and Inspection List

5.2.1 Daily Management
As daily management, check the items listed in Table 5-1 "Daily Inspection Items" and record the results. Logging these operation data on a daily basis aid in finding out any abnormal conditions of the
compressor. This is significantly effective in preventing compressor failures. It is particularly important to check whether the temperature/pressure correlations related to the refrigerant evaporation and condensation is proper. This makes it possible to quickly find out problems in the compressor or the system. If a failure or accident should occur in the compressor or the system, the operation logbook will help determine the cause and take prompt and proper actions.

Daily Maintenance Items

1. Lubrication oil level
When the oil level in the oil separator reaches the lower limit, charge lubricating oil by referring to the instruction manual of the unit.

2. Replacing oil filter element
When the differential pressure between the inlet and out let ports of the oil filter exceeds 0.1 MPa, replace the oil filter element. At the beginning of the operation, the differential pressure of the oil filter may increase quickly.

3. Cleaning of suction strainer
When the compressor operating hours exceeds 500, check the suction strainer. If a temporary filter is installed for the initial stage of operation, remove it. At the beginning of the operation or after periodical check, the differential pressure between the front and back of the suction strainer may increase quickly. If the differential pressure becomes large, check and clean the suction strainer.

4. Lubricating oil leak rate from mechanical seal
If much oil leaks from the mechanical seal, determine the leak rate per hour. The following table shows guidelines for allowable leak rate and the rate at which inspection must be done. If any problem (damage, etc.) is found in mechanical seal, replace the mechanical seal.

5. Contamination on the cooling water side of the cooling pipes of condenser and oil cooler
Clogging and contamination of the cooling pipe is largely affected by the quality of cooling water. When the oil temperature and discharge pressure gradually rise during the initial stage of operation, inspect and clean the cooling water side of oil cooler and condenser even when the time has not yet come at which inspection must be done.

 

 

P/N Part Name Code No. Remarks Qty
1-1 Main Rotor Casing (1) CS00100-250L 250L** 1 (L*C)
1-1 Main Rotor Casing (1) CS00100-250M 250M** 1 (M*C)
1-1 Main Rotor Casing (1) CS00100-250S 250S** 1 (S*C)
1-2 Main Rotor Casing (2) CS00100-200L 200L** 1 (*LC)
1-2 Main Rotor Casing (2) CS00100-200M 200M** 1 (*MC)
1-2 Main Rotor Casing (2) CS00100-200S 200S** 1 (*SC)
2-1 Hexagon Socket Head Cap Screw NB35420-060 M20×60 44
2-2 Hexagon Socket Head Cap Screw NB35416-050 M16×50 50
3-1 Alignment Pin NE2016-070 Φ16×70 4
3-2 Alignment Pin NE2016-055 Φ16×55 4
4-1 Eye Bolt NB600-30 M30 1
4-2 Eye Bolt NB600-24 M24 1
5-1 Suction Cover (1) CS00500-2520C1 2520**C 1
5-2 Suction Cover (2) CS00500-2520C2 2520**C 1
6-1 Gasket, Suction Cover (1) CS00600-250N 250*** 1
6-2 Gasket, Suction Cover (2) CS00600-200N 200*** 1
7-1 Eye Bolt NB600-12 M12 2
7-2 Eye Bolt NB600-12 M12 1
8-1 Spring Pin (1) NE3206-012 Φ6×12 2
8-2 Spring Pin (2) NE3206-012 Φ6×12 2
9 O-ring PA11-040 JIS B 2401 P40 1
10-1A Plug NF06-15 R1/2 3
10-1B Plug NF06-10 R3/8 2
10-2 Plug NF06-008 R1/4 1
11-1 Bearing Head (1) CS01100-2520C1 2520**C 1
11-2 Bearing Head (2) CS01100-2520C2 2520**C 1
12-1 Gasket, Bearing Head (1) CS01200-250N 250*** 1
12-2 Gasket, Bearing Head (2) CS01200-200N 200*** 1
13-1 Eye Bolt NB600-36 M36 1
13-2 Eye Bolt NB600-36 M36 1
14-1 Spring Pin NE3206-012 Φ6×12 2
14-2 Spring Pin NE3206-012 Φ6×12 2
15-1 Plug NF06-020 R3/4 1
16 Bearing Cover CS01600-2520C 2520**C 1
17-1 Gasket, Bearing Cover (1) CS01700-2520C1N 2520**C 1
17-2 Gasket, Bearing Cover (2) CS01700-2520C2N 2520**C 1
18-1 Hexagon Socket Head Cap Screw NB35416-050 M16×50 20
18-2 Hexagon Socket Head Cap Screw NB35420-060 M20×60 33
19-1 Alignment Pin NE2010-050 Φ10×50 2
19-2 Alignment Pin NE2016-070 Φ16×70 2
20 Spring Pin NE3203-010 Φ3×10 1
21 Plug NF06-004 R1/8 1
22 Balance Piston Cover CS02200-2520C 2520**C 1
23 Gasket, Balance Piston Cover CS02300-2520CN 2520**C 1
24 Hexagon Socket Head Cap Screw NB35416-050 M16×50 18
25-1 Male Rotor (1) - 2520L*C 1 (L*C)
26-1 Female Rotor (1)
25-1 Male Rotor (1) - 2520M*C 1 (M*C)
26-1 Female Rotor (1) 2201M2JE-HO-C7-N_2015.05.

Compound 2-stage Screw Compressor 2520**C 7.2 Parts Configuration Table 7-17
P/N Part Name Code No. Remarks Qty
25-1 Male Rotor (1) - 2520S*C 1 (S*C)
26-1 Female Rotor (1)
25-2 Male Rotor (2) - 2520*LC 1 (*LC)
26-2 Female Rotor (2)
25-2 Male Rotor (2) - 2520*MC 1 (*MC)
26-2 Female Rotor (2)
25-2 Male Rotor (2) - 2520*SC 1 (*SC)
26-2 Female Rotor (2)
27-1 Main Bearing (1) CS0270-FRT 250*** with O-ring 2
27-2 Main Bearing (2) CS0270-ERT 200*** with O-ring 2
28-1 Side Bearing (1) CS0280-FRT 250*** with O-ring 2
28-2 Side Bearing (2) CS0280-ERT 200*** with O-ring 2
29-1 Snap Snap Ring (1) C type internal NG11-160 H160 4
29-2 Snap Ring (2) C type internal NG11-130 H130 4
30 Balance Piston CS03000-2520C 2520**C 1
31 Key, Balance Piston CS03100-200 200*** 1
32 Snap Ring C type external NG12-065 S65 1
33 Sleeve, Balance Piston CS03300-2520C 2520**C 1
34 Set Screw NA83608-015 M8×15 2
35 O-ring PA11-140 JIS B 2401 P140 1
37 Snap Ring C type internal NG11-150 H150 1
38-1 Thrust Bearing (1) CS03800-250P 7317B PPS 2
38-2 Thrust Bearing (2) CS03800-200P 7313B PPS 2
39-1 Lock Nut (1) NG31-017 AN17 2
39-2 Lock Nut (2) NG31-013 AN13 2
40-1 Lock Washer (1) NG32-017 AW17 2
40-2 Lock Washer (2) NG32-013 AW13 2
41-2 Spacer, Thrust Bearing Outer Race (2) CS04100-200 200*** 2
42-1 Spacer, Thrust Bearing Alignment (1) CS04200-B250 250*** 2
42-2 Spacer, Thrust Bearing Alignment (2) CS04200-200 200*** 2
43-1 Thrust Bearing Gland (1) CS04300-250S 250*** 2
43-2A Thrust Bearing Gland (2) A CS04300-200S 200*** 2
43-2B Thrust Bearing Gland (2) B CS04300-2520C2B 2520**C 1
43-2C Thrust Bearing Gland (2) C CS04300-2520C2C 2520**C 1
43-2D Thrust Bearing Gland (2) D CS04300-2520C2D 2520**C 1
45-1 Hexagon Head Bolt NB111016-045 M16×45 8
45-2 Hexagon Head Bolt NB111012-035 M12×35 8
46-1 Conical Spring Washer (1) ND150-016 250*** 8
46-1 Lock Washer (1) Set (old, plate type) CS0469-F 250*** 8ps/set -
46-2 Conical Spring Washer (2) ND150-012 200*** 8
46-2 Lock Washer (2) Set (old, plate type) CS0469-E 200*** 8ps/set -
48 Retainer, Oil Seal CS04800-250VDS 250V** 1
49 O-ring PA12-135 JIS B 2401 G135 1
50 Oil Seal CS05010-250VD SA1J 75×100×13 1
51 Seal Cover CS05102-250 250*** 1
52 Gasket, Seal Cover CS05200-250N 250*** 1
53 Hexagon Socket Head Cap Screw NB35412-030 M12×30 8
54-1 Unloader Slide Valve (1-1) (L Port) CS05400-2520**** 2520LSC 1 (L*C)
54-1 Unloader Slide Valve (1-1) (M Port) - 2520LSC 1 (L*C)
54-1 Unloader Slide Valve (1-1) (L Port) - 2520MSC 1 (M*S)
54-1 Unloader Slide Valve (1-1) (M Port) - 2520MSC 1 (M*C)
54-1 Unloader Slide Valve (1-1) (L Port) - 2520SSC 1 (S*C) 2201M2JE-HO-C7-N_2015.05.

Compound 2-stage Screw Compressor 2520**C 7.2 Parts Configuration Table 7-18
P/N Part Name Code No. Remarks Qty
54-1 Unloader Slide Valve (1-1) (M Port) - 2520SSC 1 (S*C)
54-2 Unloader Slide Valve (1-2) (L Port) - 2520LSC 1 (*SC)
54-2 Unloader Slide Valve (1-2) (M Port) - 2520LSC 1 (*SC)
54-2 Unloader Slide Valve (1-2) (L Port) - 2520LMC 1 (*MC)
54-2 Unloader Slide Valve (1-2) (M Port) - 2520LMC 1 (*MC)
54-2 Unloader Slide Valve (1-2) (L Port) - 2520SLC 1 (*LC)
54-2 Unloader Slide Valve (1-2) (M Port) - 2520SLC 1 (*LC)
55-1 Unloader Slide Valve (2-1) - 250L** 1 (L*C)
55-1 Unloader Slide Valve (2-1) - 250M** 1 (M*C)
55-1 Unloader Slide Valve (2-1) - 250S** 1 (S*C)
55-2 Unloader Slide Valve (2-2) - 200L** 1 (*LC)
55-2 Unloader Slide Valve (2-2) - 200M** 1 (*MC)
55-2 Unloader Slide Valve (2-2) - 200S** 1 (*SC)
58-1 Hexagon Socket Head Cap Screw NB35412-040 M12×40 4
58-2 Hexagon Socket Head Cap Screw NB35410-030 M10×30 4
59 O-ring PA11-026 JIS B 2401 P26 1
60-1 Unloader Cylinder (1) CS06000-2520C1 2520LSC 1
60-2 Unloader Cylinder (2) CS06000-2520C2 2520LSC 1 (*MC/*SC)
60-2 Unloader Cylinder (2) CS06000-2520SLC 2520SLC 1 (*LC)
61-1 Hexagon Socket Head Cap Screw NB35416-140 M16×140 9
61-2 Hexagon Socket Head Cap Screw NB35412-090 M12×90 9
63-1 O-ring PA12-150 JIS B 2401 G150 1
63-2 O-ring PA12-150 JIS B 2401 G150 1
64-1 Unloader Piston (1) CS06400-2520T 2520**C 1
64-2 Unloader Piston (2) CS06400-200T 200*** 1
65-1 O-ring PA11-125 JIS B 2401 P125 1
65-2 O-ring PA11-125 JIS B 2401 P125 1
66-1 Cap Seal CS06600-200 200*** BE125 1
66-2 Cap Seal CS06600-200 200*** BE125 1
67-1 Push Rod, Unloader Slide Valve (1) CS06700-2520C1 2520LSC 1
67-2 Push Rod, Unloader Slide Valve (2) CS06700-2520C2 2520LSC 1 (*SC)
67-2 Push Rod,Unloader Slide Valve (2) CS06700-2520SLC 2520LMC 1 (*MC)
67-2 Push Rod, Unloader Slide Valve (2) CS06700-2520C2 2520SLC 1 (*LC)
68-1 Guide Pin NE2505-012 Φ5×12 1
68-2 Guide Pin NE2505-012 Φ5×12 1
69-1 Lock Nut (1) NG31-008 AN08 1
69-2 Lock Nut (2) NG31-007 AN07 1
70-1 Lock Washer (1) NG32-008 AW08 1
70-2 Lock Washer (2) NG32-007 AW07 1
71-1 Lock Nut (1) NG31-008 AN08 1
71-2 Lock Nut (2) NG31-007 AN07 1
72-1 Lock Washer (1) NG32-008 AW08 1
72-2 Lock Washer (2) NG32-007 AW07 1
73-1 O-ring PA12-035 JIS B 2401 G35 1
73-2 O-ring PA12-030 JIS B 2401 G30 1
74-1 Unloader Cover (1) CS07460-200 200*** 1
74-2 Unloader Cover (2) CS07400-200S 200*** 1
75 O-ring PA12-135 JIS B 2401 G135 2
76 Hexagon Socket Head Cap Screw NB35410-025 M10×25 16
77-1 Indicator Cam (1) CS07700-2520C 2520LSC 1 (L*C)
77-1 Indicator Cam (1) CS07700-200S 2520MSC 1 (M*C) 2201M2JE-HO-C7-N_2015.05.

Compound 2-stage Screw Compressor 2520**C 7.2 Parts Configuration Table 7-19
P/N Part Name Code No. Remarks Qty
77-1 Indicator Cam (1) CS07700-2520SSC 2520SSC 1 (S*C)
77-2 Indicator Cam (2) CS07700-200L 200L** 1 (*LC)
77-2 Indicator Cam (2) CS07700-200M 200M** 1 (*MC)
77-2 Indicator Cam (2) CS07700-200S 200S** 1 (*SC)
78 Ball Bearing CS07800-200 #6000 2
79 Snap Ring C type external NG12-010 S10 2
80 Bearing Gland CS08000-200 200*** 2
81 Hexagon Socket Head Cap Screw NB35406-015 M6×15 6
82 V-ring CS08200-200B VH10 NBR 2
83 Spring CS08300-200 200*** 2
84 Retainer, Indicator Cam Spring CS08400-200 200*** 2
85 Oil Injection Pipe CS08500-250LUK 250L** 1 (L*C)
85 Oil Injection Pipe CS08500-2520US C 2520MSC 1 (M*C)
85 Oil Injection Pipe CS08500-2520SSK 2520SSC 1 (S*C)
86 O-ring PA12-025 JIS B 2401 G25 1
87-1 Guide Block (1) CS08700-250 250***1
88-1 Stem, Guide Block (1) 1
87-2 Guide Block (2) CS08700-200 200***1
88-2 Stem, Guide Block (2) 1
89 O-ring PA11-020 JIS B 2401 P20 4
91 Shaft Key CS09100-250 250*** 1
92-1 Suction Flange (1) with hole CS71300-250MK JIS 20K 250A(10") -
92-1 Suction Flange (1) without hole CS71300-P250 JIS 20K 250A(10") 1
92-2 Suction Flange (2) with hole CS71300-150MK JIS 20K 150A(6") -
92-2 Suction Flange (2) without hole CS71300-P150 JIS 20K 150A(6") 1
93-1 Gasket, Suction Flange (1) CS71200-250N JIS 20K 250A(10") 1
93-2 Gasket, Suction Flange (2) CS71200-150N JIS 20K 150A(6") 1
94-1 Hexagon Head Bolt NB12024-065 M24×65 12
94-2 Hexagon Head Bolt NB12022-055 M22×55 12
95-1 Discharge Flange (1) with hole CS71300-150MK JIS 20K 150A(6") -
95-1 Discharge Flange (1) without hole CS71300-P150 JIS 20K 150A(6") 1
95-2 Discharge Flange (2) with hole CS71300-100MK JIS 20K 100A(4") -
95-2 Discharge Flange (2) without hole CS71300-P100 JIS 20K 100A(4") 1
96-1 Gasket, Discharge Flange (1) CS71200-150N JIS 20K 150A(6") 1
96-2 Gasket, Discharge Flange (2) CS71200-100N JIS 20K 100A(4") 1
97-1 Hexagon Head Bolt NB12022-055 M22×55 12
97-2 Hexagon Head Bolt NB12020-055 M20×55 8
100 Mechanical Seal Assembly (BOS-E1) CS10000-250BE 250V** BOS -
100 Mechanical Seal Assembly (BBSE) CS10002-250EBS BBS-E 1
100 Mechanical Seal Assembly (BBS3) CS10001-250BBS BBS3 -
120-1 Unloader Indicator Assembly (1) CS12000-200F 200*** 1
120-2 Unloader Indicator Assembly (2) CS12000-2016 2016C(2) 20-100 % 1
125 Micro-Switch CS12500-200 200*** Z15GW 4
127-1 Micro-Switch Cam (1) CS12700-200F 200*** 0-100 % 1
127-2 Micro-Switch Cam (2) CS12700-201620 2016C(2) 20-100 % 1
128 Set Screw, Bevel Gear NA83604-005 M4×5 2
129 Potentiometer 200-1k CS1299-E10 with lead wire 2
137-1 Indicator Dial (1) CS13700-200 200*** 1
137-2 Indicator Dial (2) CS13700-2016 2016C(2) 20-100 % 1 - Gear Coupling Assembly (new) CS1519-L 151+152+153+159 12201M2JE-HO-C7-N_2015.05.

Compound 2-stage Screw Compressor 2520**C 7.2 Parts Configuration Table 7-20
P/N Part Name Code No. Remarks Qty
151 Driven Sleeve CS1519-L (same as old and new type) 1
152 Drive Hub 1
153 Driven Hub 1
154 Stopper, Drive Sleeve CS15400-2520C Old part of coupling (2)
155 Stop Ring - Old part of coupling (2)
157 Key, Driven Hub CS15700-2520CH FRS-110 1
158 Key, Drive Hub CS15800-2520CH FRS-110 1
159 Set Screw NA83612-020 M12×20 knurled, with anti-loosening 1
160 Lock Nut NG31-013 AN13 1
161 Lock Washer NG32-013 AW13 1
162 Hexagon Socket Head Cap Screw NB35412-045 M12×45 5
163 O-ring PA12-035 JIS B 2401 G35 1
164 Retainer, Oil Injection Pipe CS16400-2520C 2520LSC 1
165 O-ring PA12-030 JIS B 2401 G30 1
166 Hexagon Socket Head Cap Screw NB35408-030 M8×30 4
168 Pipe Guide, Oil Injection CS16800-2520C 2520LSC 1
197 O-ring PA11-050 JIS B 2401 P50 1
200 Fixture Ass’y, Unloader Indicator (1) CS20000-2520C 2520LSC(1) 1
200A Fixture, Unloader Indicator (A) CS20000-2520CA 2520LSC 1
200B Fixture, Unloader Indicator (B) CS20000-2520CB 2520LSC 1
201 Bevel Gear (1) CS20100-1612C9 1612LSC (Φ9) 1
202 Bevel Gear (2) CS20100-1612C6 1612LSC( Φ6) 1
206 Glass Gland, Unloader Indicator CS20600-1612 1612LSC 1
208 Shaft, Unloader Indicator CS12200-2520 2520LSC 1
208A Snap Ring, Unloader Indicator Shaft NG12-010 S10 C type external 2
208B Bearing, Unloader Indicator Shaft CS16460-200 #6000LL 2
210 Cross-recessed and Pan Head Screw NB35405-015 M5×15 4
212A Hexagon Socket Head Cap Screw NB35405-030 M8×30 2
212B Hexagon Socket Head Cap Screw NB35408-095 M8×95 2
212C Hexagon Socket Head Cap Screw NB35408-020 M8×20 4
212D Spring Washer ND320-008 For M8 8
215-1 Flange, Lubricating Oil Supply (1) without hole CS71300-025 JIS 20K 25A(1") 1
215-2 Flange, Lubricating Oil Supply (2) without hole CS71300-020 JIS 20K 20A(3/4") 1
216-1 Gasket, Lubricating Oil Supply Flange (1) CS71200-025N JIS 20K 25A(1") 1
216-2 Gasket, Lubricating Oil Supply Flange (2) CS71200-020N JIS 20K 20A(3/4") 1
217-1 Hexagon Head Bolt NB12016-045 M16×45 4
217-2 Hexagon Head Bolt NB12012-035 M12×35 4
218 Flange, Injection Oil Supply without hole CS71300-015 JIS 20K 15A(1/2") 1
219 Gasket, Injection Oil Supply Flange CS71200-015N JIS 20K 15A(1/2") 1
220 Hexagon Head Bolt NB111012-035 M12×35 4
237-1 Torsional Slip Washer (1) CS23700-250 250*** 2
237-2 Torsional Slip Washer (2) CS23700-200 200*** 2
245 Spring Washer ND330-12 M12 5
250-1 Thrust Bearing Washer (1) CS25000-250 250*** 2
250-2 Thrust Bearing Washer (2) CS25000-200 200*** 1
267-1 Spring Washer, Hexagon Socket Head Cap Screw ND330-12 M12 4
267-2 Spring Washer, Hexagon Socket Head Cap Screw ND330-10 M10 4
278A Cylinder Guide, Unloader (A) CS27800-2520CA 2520LSC 1 2201M2JE-HO-C7-N_2015.05.

Compound 2-stage Screw Compressor 2520**C 7.2 Parts Configuration Table 7-21
P/N Part Name Code No. Remarks Qty
278B Cylinder Guide, Unloader (B) CS27800-2520LMS 2520*MC, 2520*LC 1 (*LC/*MC)
278B Cylinder Guide, Unloader (B) CS27800-2520S 2520*SC 1 (*SC))
279 O-ring PA12-130 JIS B 2401 G130 1
432-1 O-ring PA12-130 JIS B 2401 G130 4
432-2 O-ring (Old JIS W 1516 G22) PA62-022 AS568A-244 4
433-1 O-ring PA12-130 JISB2401 1A G130 4
433-2 O-ring (Old JIS W 1516 G22) PA62-022 AS568A-244 4
528 Sleeve, Oil Seal CS52800-250VD 250V** 1
528 Sleeve with O-ring, Oil Seal CS52809-250VD 250V** 1
529 Set Screw NA83606-008 M6×8 2
605-1 Plug NF06-020 R3/4 1
605-2 Plug NF06-025 R 1" 1
607 Plug NF06-008 R1/4 2
744 O-ring PA12-070 JIS B 2401 G70 1

The sizes of O-ring No.432-2 and No.432-2 have been changed to G130 from G135 in October 2012 as a design change.

The Code No. of the O-ring is the one assigned to NBR which is standard material. When the material of the O-ring is other than NBR, a different Code No. is used for each material.
If you are using O-rings made from other than the standard material, please contact SCS when placing an order.

The SLC and SMC models are excluded from the above tables. If you need any relevant information, please contact our sales offices or service centers. 2201M2JE-HO-C7-N_2015.05.

Compound 2-stage Screw Compressor 2520**C 7.3 Tightening Torques for Bolts and Nuts 7-22
7.3 Tightening Torques for Bolts and Nuts Table 7-2 List of Tightening Torques

Hexagon Socket Head Cap Screw P/N What is Tightened Tightening Torque Qty. Size N·m kgf·cm
2-1 Rotor Casing (1), Suction Cover (1) and Bearing Head (1) 450 4500 44 M20×60
2-2 Rotor Casing (2), Suction Cover (2), Bearing Head (2) 240 2400 50 M16×50
18-1 Bearing Cover and Bearing Head (1) 240 2400 20 M16×50
18-2 Suction Cover (1) and Bearing Head (2) 450 4500 33 M20×60
24 Balance Piston Cover and Suction Cover (2) 240 2400 18 M16×50
53 Seal Cover and Bearing Cover 90 900 8 M12×30
58-1 For Securing Unloader Slide Valve 90 900 4 M12×40
58-2 For Securing Unloader Slide Valve 50 500 4 M10×30
61-1 Unloader Cylinder (1) and Bearing Cover 240 2400 9 M16×140
61-2 Unloader Cylinder (2) and Balance Piston Cover 90 900 9 M12×90
76 Unloader Cover (1), (2) and Unloader Cylinder (1), (2) 50 500 16 M10×25
81 Bearing Gland 10 100 6 M6×15
162 Push Rod, Unloader Slide Valve (1) 90 900 5 M12×45
166 Oil Injection Pipe Retainer 25 250 4 M8×30

Hexagon Head Bolt P/N What is Tightened Tightening Torque Qty. Size N·m kgf·cm
45-1 Thrust Bearing Gland (1) 60 600 8 M16×45
45-2 Thrust Bearing Gland (2) 50 500 8 M12×35
94-1 Suction Flange (1) JIS20K 150A 750 7500 12 M24×65
94-2 Suction Flange (intermediate pipe) (2) JIS20K 150A 240 2400 12 M22×55
97-1 Discharge Flange (intermediate pipe) (1) JIS20K 150A 240 2400 12 M22×55
97-2 Discharge Flange (2) JIS20K 100A 180 1800 8 M20×55
217-1 Journal Lubricant Supply Flange (1) JIS20K 25A 120 1200 4 M16×45
217-2 Journal Lubricant Supply Flange (2) JIS20K 20A 70 700 4 M12×35
220 Lubricant Injection Flange JIS20K 15A 70 700 4 M12×35
2201M2JE-HO-C7-N_2015.05.

Compound 2-stage Screw Compressor 2520**C 7.3 Tightening Torques for Bolts and Nuts 7-23

Lock Nut P/N What is Tightened Tightening Torque (N·m) Qty. Size Standard Maximum
39-1 Thrust Bearing (1) Note 1 1186 1483 2 AN17
39-2 Thrust Bearing (2) Note 1 522 653 2 AN13
69-1 Unloader Piston (1) 140 - 1 AN08
69-2 Unloader Piston (2) 120 - 1 AN07
71-1 Unloader Slide Valve (1-1) 90 113 1 AN08
71-2 Unloader Slide Valve (1-2) 79 99 1 AN07
160 Gear Coupling Drive Hub Note 1 522 653 1 AN13
Note 1: When tightening a lock nut, if it is difficult to use a torque wrench, manage the tightening torque of the lock nut controlling the tightening angle range as explained below. Tightening Angle Range of Lock Nuts for Rotors
a) After tightening the lock nut by hand, further tighten the lock nut by using a lock nut wrench until the rotor starts to turn. Take care not to over-tighten.
b) Put a mark on the lock nut at the right side edge of the rotor groove where the stopper tongue of the lock washer fits in, as shown in Figure 7-16.
c) From this marking position, tighten the lock nut in such a way that rotation can be stopped within the tightening angle range shown in Table 7-3 (2016**C [39-1], [39-2] and [160]: 30° to 40°(first time tightening), 20° to 30°(second time tightening). When measuring the angle, use an angle gauge which is set to the diameter of rotor shaft.

Table 7-3 Tightening Angles Specified for Lock Nuts of Rotor Model Angle range First time tightening 200 (High-stage) 250 (Low-stage) 30° to 40° Second time
tightening 200 (High-stage) 250 (Low-stage) 20° to 30° * When tightening lock nut, tightening start position differs between the first time tightening and the tightening for the second time or after. Therefore, angle ranges are specified also for the second time tightening.

Figure 7-16 Position where mark is put Photo 139 Angle gauge (example) Marking Rotor groove (slot) where stopper tongue of the lock washer fits 2201M2JE-HO-C7-N_2015.05.

Compound 2-stage Screw Compressor 2520**C 7.4 About the O-rings Used 7-24
7.4 About the O-rings Used
7.4.1 List of O-rings Used

Table 7-4 List of O-rings Used P/N Location Designation Installation Part Functional Description (Conventional) 9 Suction Cover (2) Rod, Push (2) P40
35 Sleeve, Balance Piston Same as left P140
49 Seal Retainer Same as left G135
59 Pipe Guide, Oil Injection Pipe, Oil Injection P26
63-1 Cover, Bearing Cylinder, Unloader (1) G150
63-2 Guide, Unloader B Cylinder, Unloader (2) G150
65-1 Unloader Piston (1) Same as left P125
65-2 Unloader Piston (2) Same as left P125
73-1 Rod, Unloader Push (1) Unloader Piston (1) G35
73-2 Rod, Unloader Push (2) Unloader Piston (2) G30
75 Unloader Cylinder Cover (1), (2) Same as left G135
86 Oil Injection Pipe Same as left G25
89 Stem, Guide Block (1), (2) Same as left P20
163 Unloader Slide Valve (1) Same as left G35
165 Retainer, Oil Injection Pipe Same as left G30
197 Cover, Bearing Rod, Unloader Push (1) P50
279 Balance, Piston Cover Guide, Unloader Cylinder B G130
432-1 Main Bearing (1) Same as left G130
432-2 Main Bearing (2) Same as left AS568A-244
433-1 Side Bearing (1) Same as left G130
433-2 Side Bearing (2) Same as left AS568A-244
744 Sleeve, Oil Seal Same as left G70
Designation codes are based on JIS B 2401 except AS568A-244.
"Installation Part" refers to a component with groove or tapered portion for installing an O-ring.
7.4.2 O-ring Materials Used for Screw Compressor
Table 7-5 List of O-ring Materials Used for Screw Compressor (Excluding Mechanical Seal) Working fluid O-ring Material Ammonia NBR Hydrofluorocarbon (HFC) CO2 FKM HNBR Trifluoromethane (R23) FKM Propane Propylene Natural gas City gas Helium