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ZS Screw blower Sittisak.T
ZS Screw blower
Sittisak.T
2
ZS Low Pressure Screw blower
Agenda Applications
Products range
Scope of supply
Why is the screw so much more efficient?
ISO1217
3
Low pressure applications
4
Low pressure applications
Low Pressure Product Portfolio
55
(bar(g))
1.5
1.0
0.5
0
0(m3/hr)
4.000 6.000 8.0002.000 16.000
ZB+
ZS
ZS+
70.000
4
ZE/A 2 -6
HSI –HT series
HSI – MC series
6
Low Pressure screw blower Scope of supply
Basic– Base frame with forklift slots– 100% oil free element (Class 0)– Integrated gear-box (no belts)– TEFC IP55 motor – Air-outlet (silencer, BOV)– Oil-circuit (pump and cooler)– Air-inlet (filter)– Discharge pressure gauge– Oil pressure switch– Decoupling between air filter and
element– Decoupling between element and
pulsation damper– Comes with fixed speed (Y/Δ) motor
as standard. VSD type motor as an option ZS55 basic
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ZS Low Pressure screw blower Scope of supply
Standard– Base frame with forklift slots– 100% oil free element (Class 0)– Integrated gear-box (no belts)– TEFC IP55 – Air-outlet (silencer, BOV)– Oil-circuit (pump and cooler)– Air-inlet (filter)– Discharge pressure gauge– Oil pressure switch– Decoupling between air filter and element– Decoupling between element and pulsation
damper– Canopy
78 dB(A) at 1 bar and full speed. 74 dB(A) at 0.6 bar and full speed
– Comes with fixed speed (Y/Δ) motor as standard. VSD type motor as an option
– No starter and no Elektronikon
ZS55 standard
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ZS Low Pressure Screw blower
Scope of supply ZS+ VSD
– Base frame with forklift slots– 100% oil free element (Class 0)– Integrated gear-box (no belts)– TEFC IP55 Eff 1 motor– Air-outlet (silencer, BOV with pressure
control)– Oil-circuit (pump and cooler)– Air-inlet (filter)– Decoupling between air filter and element– Decoupling between element and pulsation
damper– Elektronikon controller for improved
performance – larger turndown– Improved sound enclosure (72 dB(A))– Integrated VSD converter ZS37+ VSD
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ZS Low Pressure Screw blower Scope of supply
Air filter– Dry paper filter– Same as used on ZR/T range– Efficiency SAE fine particle size
0,001 mm 98 % 0,002 mm 99.5 % 0,003 mm 99.9 %
Air filter differential gauge– Provides visual view of air filter pressure
differential. – Change air filter when differential reaches
50 mbar
Air discharge pressure gauge– 50 mm diameter – Bar and psi display– Dry type
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ZS Low Pressure Screw blower Scope of supply
Flexible hose – To provide a vibration decoupling between
the element and the filter housing.– On tri-lobe blowers serious cracking on the
filter housing can occur due to having no de-coupling
– On ZS it is not a concern but we can use this feature as a positive design feature over tri-lobes
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ZS Low Pressure Screw blower Scope of supply – compression element
ZS element– 100% oil free element (Class 0)– Coated with the same coating as the Z stages
Coating consists of a teflon & a teflon grahite layer
– Timing gears like the Z’s but on drive end– Non-drive end is greased for life bearings
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ZS Low Pressure Screw blowerScope of supply – compression element
Timing gears on the non-drive end
Lubricated bearings on both drive end and non-drive end
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ZS Low Pressure Screw blowerScope of supply
Flexible hose – To provide a vibration decoupling between the
element and silencer– On tri-lobe units serious failures of the silencers can
occur.– It is not an issue on the ZS due to the screw element
delivering higher frequency, low pulsation air but let’s use it to attack lobes.
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ZS Low Pressure Screw blower Scope of supply
Gearbox– Transfers motor power to element more efficiently
than belt / pulley – Belt / pulley = approx. 93% efficient– Gearbox = approx. 98% efficient– No risk of misalignment – Belts needs to be replaced every year
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ZS Low Pressure Screw blower Scope of supply
Start up valve– Closes when the pressure builds between 0.1 bar and 0.2 bar (1.5 psi and
3psi)– The valve is in the open position when the blower is off.– When the blower is started against a counter pressure, the air is blown off
through the main opening of the valve (1).– By increasing the air flow, a slight overpressure is generated in the pipe (2)
and the bellows (3) are filled with air.– When the pressure on the surface of the base plate (5) in the bellows has
become bigger than the pressure on the main opening of the valve (1), the base plate closes the valve.
– The unit is in load status.
1
2
5
3
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ZS Low Pressure Screw blower Scope of supply
Start up valve– When the unit will be stopped, the air in the bellows will escape through the
pipe. The pressure on the base plate diminishes and the springs (4) will open the valve.
4
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ZS Low Pressure Screw blower Scope of supply
Bursting disc– The bursting disc is the safety device to
ensure that any over pressure is released quickly.
– It is designed to protect the blower from over pressure.
– The bursting disc is used for PED accuracy and cost.
– Once the disc breaks it has to be replaced with a new one.
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ZS Low Pressure Screw blower Scope of supply
Check valve– Swing type – Prevents air from network entering the
element.– Low pressure drop design
Silencer– Reduce noise and pulsations generated
by element– Damping material is stainless steel wool
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ZS Low Pressure Screw blower Scope of supply – oil circuit
Oil pump– Pumps oil from the tank (15 litre) to the bearings and gears– 50 Hz: 370 watt; 400V; 3phase – 60 Hz: 430 watt; 440-460V; 3 phase
Oil filter– Filters any particles from the oil – Genuine Atlas Copco oil filter
Oil cooler and cooling fan– To cool the oil prior to lubrication of gears– This is a big selling feature. Cooled oil has a much longer lifetime– 50Hz: 95 watt; 230V; 1 phase 1690 m3/hr cooling air flow– 60Hz: 94 watt; 115V; 1 phase 1420 m3/hr cooling air flow
Oil type– Roto Z
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ZS Low Pressure Screw blower Why is the screw so much more efficient?
Working principle and pV-diagram
Adiabatic efficiency
Air temperature at outlet
Pressure pulsations
Conclusions
p
flow
Screw
Roots
200m³/h 5000m³/h
atm
1bar
Roots blower working principle
Air intake at inlet side
Air transport External compression by back flow
Force out air to discharge line
Air transport
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Roots blower : pressure-volume diagram
4-1 : Air intake; volume increase to Vs
1-2 : Compression by back-flow from receiver to blower
2-3 : Air delivery from blower to receiver
Rectangle area 1-2-3-4 represents the compression work Wt
Power consumption is proportional with blue area 1-2-3-4
p
V1
23
Vs
p1
pe
4
p1 = air intake pressure pe = working pressure (external system pressure)Vs = displaced volume
Wt
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Working principle
Inlet port
Male rotor
Female rotor
Example: B111
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Working principle
Volume of inlet chamber increases when rotating the rotors: air is sucked in
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Working principle
Volume of inlet chamber increases when rotating the rotors: air is sucked in
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Working principle
Volume of inlet chamber increases when rotating the rotors: air is sucked in
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Working principle
Inlet port closes: Air is trapped between between rotors and housing
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Working principle
Inlet port closes: Air is trapped between between rotors and housing
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Working principle
Outlet port: much larger than OIS or OFS
When rotors rotate the volume between the rotors decreases : compression of the air
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Working principle
When rotors rotate the volume between the rotors decreases down to the built-in volume ratio : compression of the air
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Working principle
The outlet ports opens when the volume is reduced: compressed air is released from between the rotors to the outlet port
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Working principle
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Working principle
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Working principle
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Screw blower Working principle : displacement compressor with internal compression
Pressure-Volume diagram
p
1-2 : internal compression in screwblower
2-3 : Air delivery from screwblower to receiver
V1
23
VsVs/vi
p1
pi=pe
Wt
4
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Screw blower Working principle : displacement compressor with internal compression
Pressure-Volume diagram
Energy saving due to internal compression
Power consumption is proportional with blue area
p
V
1
23
Wt
36
37
38
39
40
41
42
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ZS Low Pressure Screw blower Summary
Screw blowers
+ 1.25 bar(e) or more
+ High efficiency (~30% less SER), Package warrantee
+ Lower outlet temp
+ Noise level: 70 -73 dB(A)
+ Higher frequency pulsations
+ Internal VSD,Large turndown: 200m3/hr to 1100m3/hr on ZS37+ VSD, VSD’s motor,no speed window.
+ Integrated concept: small footprint
+ Oil cooler: High reliability and lifetime
+ Complete package ,No hidden cost
Roots type blowers
− Max 0.8 to 1.0 bar(e)
− Poor efficiency, No package performance warrantee
− High outlet temp
− High noise level: 75 -90 dB(A)
− Pressure pulsations
− External VSD ,Narrow turndown: 800m3/hr to 1100m3/hr, Speed window and high temp
− Limited reliability and lifetime
− Installation cost , check valve , safety valve , Flexible hose
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ISO 1217
Committed tosustainable productivity.
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