3. HITACHI OIL-FREE ROTARY SCREW COMPRESSOR
(1) AIR END STRUCTURE
Pinion Gear Male Rotor
Air Seal
Bearing Visco Seal
Bearing
Female
Rotor
Cooling Jacket Casing Timing Gear
3
4. HITACHI OIL-FREE ROTARY SCREW COMPRESSOR
(3) AIR END STRUCTURE
Stainless Fine Rotor Shaft Seals
The rotor profile is a Hitachi original. It Visco-type seals prevent the oil from
has a geometrical shape in order to entering the compressor chamber while
minimize internal leakage. carbon rings seal the air end.
4
5. HITACHI OIL-FREE ROTARY SCREW COMPRESSOR
(4) AIR END STRUCTURE
Bearing Timing Gear
Specially designed ball and roller bearings A pair of timing gears are precisely
are oversized and precisely made. finished and balanced dynamically to
assure optimum rotor clearance.
5
6. HITACHI OIL-FREE ROTARY SCREW COMPRESSOR
(5) DSP TECHNOLOGY, GUARDED BY PATENTS
１ Rotor Profile and Air End Design 2 Single-stage DSP Precooler
Rotor profile
which allows
heat expansion
Air End
High Performance
Precooler
To Aftercooler
Visco Seal
Check Valve
Oil Free
With the patent of Precooler,single-stage Oil-
Air End free Screw Compressor capable of producing
2
Design discharge air pressure as high as 7kgf/cm (g) is
Registration
completed.
6
7. HITACHI OIL-FREE ROTARY SCREW COMPRESSOR
(6) DSP TECHNOLOGY, GUARDED BY PATENTS
3 Air-cooled Coolant System 4 Air-cooled Hi Precooler
Pressure Cap Exhaust
Coolant Coolant cooler
Cooler
Intake Hi-
Air Intake Air
Precooler
Cooling Fan Air End
Reservoir Cooling
Air End Tank Fan Oil
Cooler
Discharge
Pipe Check
Coolant
Valve
Pump Aftercooler
● Hi-Precooler allows air cooling of
large size models.
Air-cooled type Oil-Free Screw models ● If applied in a two-stage model, air
have been developed. discharge pressure, 9kgf/cm2(g), can
be achieved. 7
8. CONSTRUCTION
55kW New DSP, Air-cooled Single stage
Suction throttle valve Circuit Board
(increased functions) Cooling Fan (1.5kW 0.9kW)
Motor Gear Case Cooler V-belt Oil Filter
Air End
（4 TEFC) (30%smaller) (V-ribbed belt) (built-in)
FRONT BACK 8
9. OPERATION
Energy saving operation --- Automatically regulates unload pressure and promotes
energy saving.
Scheduled operation --- Can be operated automatically at programmed start / stop time.
Dual control operation --- Provides dual operation without an outside control panel.
(option)
Operating data memory --- Records operating data for 12 days in memory,
which can be read out.
Shutdown history memory --- Records shutdown history and each operating condition
in memory for quick trouble shooting.
Communication --- Operating data can be sent to a personal computer via RS232C port.
Automatic restart at momentary power failure, Automatic stop and restart operation, and
Steproller can be provided as an option.
9
12. Power Save Function
Power save function
･･･ Automatically decrease cut-out pressure and save power by
lowering the average operating pressure.
When POWER SAVE mode is selected, cut-out pressure falls down automatically
so that repetition time of unload and load becomes shorter to fit in a time limit.
Cut-out.
pressure Cut-out press.
(unload start)
Line Pressure
is lowered.
Cut-in pressure
(unload stop)
Time Limit :
Load Unload Saved energy Min. 30 sec.
(Adjustable)
Time
12
16. AIR FLOW, OIL FLOW & COOLANT FLOW
. AIR FLOW
1
1. Air Filter
2. Suction Throttle Valve
8
3. Air End
2 7
4. High Pree Cooler
5. Check Valve
6. After Cooler
1
4
OIL FLOW
9. Oil reservoar
10. Oil Pump
3 1 1
2 1
11. Oil Cooler
15 12. Oil Filter
4
Distributed to bearing & gear
5
6 COOLANT FLOW
1 13. Coolant Pump
3
1 14. Coolant Cooller
0 9
Air End Water Jacket
16
17. CAPACITY CONTROL
Start & Unload
CLOSE OPEN
ATM POWER
CONSUMTION 40%
PURGE
VACUUM
0.15MPa
CLOSE
17
18. CAPACITY CONTROL
Load
CLOSE
OPEN ATM
35 ºC
OPEN
ATM 0.69 Mpa
0.69 MPa
380 ºC
0.69 Mpa
40 ºC
18
19. MAINTENANCE
Durable New V-Ribbed
V- Direct-
Direct-Coupling driven
belt driven Configuration Configuration
up to 55kW single stage Larger than 65kW two stage
and 55kW two stage
19
20. OPERATION RECORD
DATE MOTOR DISCHARGE AIR OIL COOLANT
PRESS PRESS
TIME VOLT CURRENT TEMP
LOAD UNLOAD
PRESS TEMP PRESS TEMP NOTE
MAX MAX 0.08 – 0.13 0.12 – 0.16 MAX 0.14 –0.27 MAX
H
390 ºC 0.69 MPa MPa MPa 60 ºC MPa 60 ºC
21. MAINTENANCE
Durable New V-Ribbed
V- Direct-
Direct-Coupling driven
belt driven Configuration Configuration
up to 55kW single stage Larger than 65kW two stage
and 55kW two stage
21
22. MAINTENANCE
● Improvement in working
efficiency by putting coolers on
the back side (Air-cooled type)
● Adoption of new V-ribbed belt
and the same mechanism for
belt tension with HISCREW
● Adoption of cartridge type high
performance filter
● Disuse of shaft sealing backup
air（getting rid of shaft sealing
orifice and shaft sealing filter）
● Simple structure for installation
and removal of coolant filter
● Sideways structure of inlet filter
22
23. MAINTENANCE
SCHEDULE ( A ), for 8000 operation hours per year
Daily Schedule : Checked operation data
Check Oil Level during operation
Drain Out Condensate of control line filter
Monthly Schedule : Cleaned Up Cooler
Half Yearly Schedule :
Replaced : Oil, Suction Filter
Cleaned : Control Line filter, Cooler,
Checked : Coolant Concentration, Oil Pressure, Operation of capacity control
system, Leaking of Check Valve, Shaft seal coolant pump.
Yearly Schedule :
Replaced : Suction Filter, Oil Filter, Oil, Parts of Suction Throttle Valve, Belt if
necessary,
Cleaned : Oil Strainer, Coolant Strainer, Safety Valve, Cooler,
Checked : Electrical, Motor Insulation, Joint, Bolt, Nut, Solenoide. 23
24. MAINTENANCE
SCHEDULE ( A ), for 8000 operation hours per year
2 - Yearly Schedule :
Take action as yearly schedule
Replaced :Seal Oil Pump, Bearing oil Pump, Coolant, Shaft seal coolant pump,
Pressure Cap, Check Valve, Element Control Line Filter
3 - Yearly Schedule & 5 Yearly Schedule
Take action as yearly schedule
4 – Yearly schedule :
Take action as 2-yearly maintenance
Replaced : Motor Bearing
6 – Yearly schedule
Take action as 2 yearly schedule
Replace : Air End Block, Bearing gear Case, Solenoide, Shaft seal, Coolant
Strainer, Oil Strainer, Oil temperature control Valve.
24
25. MAINTENANCE
SCHEDULE ( B ), for 4000 operation hours per year
Daily Schedule : Checked operation data
Check Oil Level during operation
Drain Out Condensate of control line filter
Monthly Schedule : Cleaned Up Cooler
Half Yearly Schedule :
Cleaned : Control Line filter, Cooler, Suction Filter,
Checked : Coolant Concentration, Oil Pressure, Operation of capacity control
system, Leaking of Check Valve, Shaft seal coolant pump.
Yearly Schedule :
Replaced : Suction Filter, Oil
Cleaned : Oil Strainer, Coolant Strainer, Safety Valve, Cooler,
Checked : Electrical, Motor Insulation, Joint, Bolt, Nut, Solenoide. , Oil Filter, Oil,
Parts of Suction Throttle Valve, Belt if necessary,
25
26. MAINTENANCE
SCHEDULE ( B ), for 4000 operation hours per year
2 - Yearly Schedule & 4 yearly Schedule :
Take action as yearly schedule
Replaced : Coolant, Oil Filter, Valve Sheet Blow off Valve
3 - Yearly Schedule, 5 Yearly Schedule & 7 Yearly Schedule
Take action as yearly schedule
Replaced : Parts of Suction Throttle Valve, Check Valve, Element Control Line
Filter, Shaft seal Coolant Pump, Belt.
6 – Yearly schedule :
Take action as 3 -yearly maintenance
Replaced : Motor Bearing
8 – Yearly schedule
Take action as 2 yearly schedule
Replace : Air End Block, Bearing gear Case, Solenoide, Shaft seal, Coolant
Strainer, Oil Strainer, Oil temperature control Valve. 26
28. OPTION
Dual Operation Function, Auto-stop/restart
Dual Operation 2 units operate in turn every setting time.
Overlap Operation
Unit 1 Master Slave Master
Unit 2 Slave Master Slave
＊Dual time ＊Dual time
＊Overlap time ＊Overlap time ＊Adjustable
Interval Operation when the power supply is limited, effective.
Unit 1 Master Slave Master
Unit 2 Slave Master Slave
＊Dual time ＊Dual time
＊Interval time ＊Interval time 28
＊Adjustable
29. OPTION
Dual Operation Function, Auto-stop/restart
Back-up Operation Pressure back-up function is added to dual operation.
Slave Master Slave
Unit 1
Load Unload Load
Master Slave Master
Unit 2
Load Load Unload Load
AUTO
stop
Pressure
＊Cut-out(0.69MPa)
＊Unload(0.67MPa)
＊ Cut-in(0.59MPa)
＊Back-up(0.54MPa)
Pressure control by pressure ＊ Dual time ＊ Dual time
29
sensor with master unit. ＊Adjustable
30. OPTION
Dual Operation Function, Auto-stop/restart
Shutdown back-up function After recovering from
shutdown, Unit 1 operates
again as a master within
remaining time. After that
Dual time unit 1 becomes a slave.
Remaining time
8 sec
Shutdown
Unit 1 Master
Unit 2 Slave Single・Slave
・
30
31. OPTION
New Oil Mist Remover OMR (Built-in)
No gear case vent piping required with this option.
99.99% oil fume removed.
Patented unique construction.
OUTSIDE INSIDE
Relief valve Filter regulator Oil Mist Remover(OMR)
31
Vacuum indicator Pressure gauge
32. OPTION
New Oil Mist Remover OMR (Built-in)
FEATURES
No need to assemble, mount nor provide wiring
1. Package built-in at site.
2. Compact 50% element space compared to conventional
unit.
3. Easy one-tough mounting No need to modify pipes on compressor side.
4. Lower Ejector air consumption 75kW models : Reduced from 110 to 60L/min.
5. Lower Ejector noise Package built-in style eliminated noise leakage.
6. Upright relief valve Oil receive plate is eliminated.
V.S. Competitor A : HITACHI has better reliability by eliminating
the condensate back flow
V.S. Competitor B : HITACHI has better reliability and performance.
32
33. OPTION
New Oil Mist Remover OMR (Built-in)
FLOW SHEET
Remover
Element
Relief Valve
Air End
Vacuum
Indicator
Air Oil Pump
Gear Case
Filter
Pressure Solenoid
Regulator Float Trap Ejector
gauge Valve 33
