At a glance
- Type
- Oil-lubricated screw
- Architecture
- Single-stage screw
- Pressure options
- 2 / 4 / 6 bar(g)
- Power range
- 7.5–160 kW
- Drive
- Permanent-magnet VFD
Overview
SILVERLUBE-VPM Low-Pressure is the SILVERLUBE S single-stage screw compressor configured for 2–6 bar(g). It keeps the permanent-magnet variable-frequency drive of the standard VPM models and is aimed at processes that want a large volume of air at low pressure rather than a small volume at high pressure. Choosing the right pressure band is the largest single energy decision in a compressed-air project; the drive choice comes second.
Model range
This low-pressure configuration covers 7.5–160 kW at 2, 4 and 6 bar(g). Delivery is specific to the model and pressure row you pick.
Pressure
2 / 4 / 6 bar(g)
- Power range
- 7.5–160 kW
- Architecture
- Single-stage screw
- Drive
- Permanent-magnet VFD
Why single-stage
Modest pressure ratio
- Ratio
- Low, so one rotor pair is enough
- Effect
- Fewer parts than a two-stage machine
- Compare with
- DUALLUBE D low-pressure two-stage
How to choose
By the process, not the machine
- Start with
- The pressure the process actually needs
- Then
- Simultaneous flow at that pressure
- Before a quote
- Confirm the model row
Technology
The pressure band comes first
A plant running at 8 bar to serve a 3 bar conveying line has already paid for compression it does not use, and no drive option gets that energy back. Matching the machine to 2, 4 or 6 bar is the step with the largest effect on the bill.
Why one stage is enough here
Below the general 7–13 bar band the pressure ratio is modest, so a single rotor pair carries it without the intercooler, the second airend and the extra service points a two-stage machine brings. If the flow is very high, the two-stage low-pressure line is the one to compare against.
VFD on a low-pressure duty
Conveying, jets and blow-off rarely draw a flat load all shift. The permanent-magnet drive trims output to the demand instead of loading and unloading at one speed.
More technical detail
Reading the duty point
Two numbers define it: the pressure the process needs at its furthest point, plus line losses; and the sum of the consumers that run at the same time, plus margin. The model row is chosen at or above that point, at the pressure row that matches.
Low pressure and moisture
Air treatment is sized on the duty as well. Low-pressure lines still need drying and filtration matched to the process — the air-quality requirement does not fall just because the pressure did.
Selection & quote checklist
- the pressure the process actually needs
- simultaneous flow at that pressure
- whether a two-stage low-pressure machine compares better
- the load profile across the shift
- air treatment matched to the same duty
- the current datasheet and package contents
Applications
Pneumatic conveying
Silos to mixers, pellets along a pipe: the line size sets the volume and the material sets the pressure.
Fermentation and aeration
Continuous low-pressure air through a liquid or bed. Hours are long, so efficiency at part load matters.
Textile air jets
Looms need steady pressure at volume; the compressor feeds a receiver close to the machines.
Blow-off and drying
Air knives and blow-off stations want volume rather than pressure, and often run intermittently.
FAQ
How low can this series go?
The line covers 2, 4 and 6 bar(g). Take the pressure from the process requirement rather than from what the plant already runs at.
Single-stage or two-stage for low pressure?
Single-stage covers most 2–6 bar duties with fewer parts. Where the flow is very high, the DUALLUBE D low-pressure two-stage range is the alternative and should be compared on the same duty and hours.
Does low pressure mean less air treatment?
No. Drying and filtration are set by the process air-quality requirement, which is independent of the pressure band.
Can I keep the plant at 8 bar and tap it down?
You can, but the compression has already been paid for. A separate low-pressure machine for the low-pressure consumers avoids that, which is usually the cheaper arrangement over a year of running.
Confirm the model row, FAD and package contents at the pressure you select.
