Two-stage screw compressor SCR-280 HPM 280 kW rating, 3,600 m³/h at 7 bar, variable-speed drive, pressure 7 / 8 / 10 / 12.5 bar

Product detailed description

280 kW · two stages

SCR-280 HPM is a two-stage screw compressor rated at 280 kW, driven by a permanent magnet motor through a variable-speed drive. It comes in four pressures — 7, 8, 10 or 12.5 bar — and at seven bar it controls its output over the range 1,020 to 3,600 m³/h. The air is compressed by two blocks in series with intercooling. Noise 86 dB(A), weight 7,400 kg, DN125 outlet.

What the SCR-280 HPM is for

The largest controlled machine of the series. It is the combination chosen for plants with a large but uneven consumption — where a line runs two shifts, say, and the third one is a shutdown.

Permanent magnet motor and drive

The motor of the SCR-280 HPM is a permanent magnet type, according to the manufacturer beyond class IE4 and in IP55 protection. The variable-speed drive holds the pressure set in the system and changes the speed to do so, so the machine does not have to blow off into the open when demand drops away. The lowest the SCR-280 HPM will turn down to at seven bar is 1,020 m³/h — that is roughly 28 % of its full output. At this size the drive comes in a separate cabinet beside the machine.

What is inside the SCR-280 HPM

Two stages, two blocks

The air goes through two screw blocks in series. The first compresses it to an intermediate pressure, the intercooler takes the heat out of it and the second pushes it up to the outlet pressure. Both blocks are driven by one motor through a gearbox, so each of them runs at the speed that suits it. According to the manufacturer the rotors are designed for twenty years of operation and they run in SKF bearings.

The oil and how it gets out

The oil lubricates the rotors, seals the gap between them and carries the heat away. It is pulled out of the compressed air by the swirl in the large vessel and, at the end, by the fine separator element; according to the manufacturer less than 3 ppm of it then stays in the air. The pressure drop of the whole separating path is under 0.02 MPa, which goes straight into the pressure the machine has to make.

SCR9000 control

A seven-inch colour touch display. It shows the pressure, the temperature and the running hours, watches the service intervals and has over thirteen protections — from overheating through overpressure to phase imbalance. Over Modbus RTU the SCR-280 HPM can be tied into a network control of up to sixteen compressors; at this size there are usually several machines in the compressor room.

SCR-280 HPM in four pressures

Mechanically it is still the same machine — what changes is the outlet pressure and with it the amount of air. You pick the pressure at the product, and the order code changes accordingly.

The lower figure is the lowest output the machine can turn down to, the upper one is its maximum. In between it controls steplessly.

What the machine demands of the plant

Cooling and space in the compressor room

The SCR-280 HPM is air-cooled as standard — the fans pull air through the oil cooler and through the aftercooler. Cold air therefore has to be brought into the compressor room and the hot air taken away. The machine measures 4,000 × 2,200 × 2,300 mm and weighs 7,400 kg, so allow for it in transport and in the assessment of the floor as well. The compressed air outlet is DN125. For hot or cramped plants water cooling is available.

What the machine costs over a year

On a 280 kW machine that runs around the clock you will pay several times more for the electricity than for the compressor itself. That is what the two stages are here for: the air is cooled between them, the second stage has an easier job, and the manufacturer puts the resulting saving at over ten percent against a single-stage machine at full load. On top of that the drive removes the hours the machine would spend running empty.

Where the air from the SCR-280 HPM is used

The series is built for plants that take air all the time and in quantity, and where the yearly electricity bill counts for more than the purchase price. The air is oil-lubricated — where it touches the product, the oil-free series belongs instead.

Equipment and accessories

What the SCR-280 HPM does as standard

• Two-stage screw block with a gearbox and SKF bearings
• Intercooler between the stages and an aftercooler at the outlet
• Oil separator vessel, oil content in the air below 3 ppm — with two elements at this size
• Intake filter with a double element and a clogging indicator, 2,000 hour interval
• Oil filter with a separation rating of 0.1 µm
• SCR9000 controller with a seven-inch touch display and Modbus RTU
• Electrical switchgear with Siemens components
• Internal air and oil pipework entirely in steel
• Variable-speed drive with CE/UL certification, EMC C2 and C3, with a built-in reactor

What can be ordered on top

• Water cooling instead of air cooling
• Heat recovery into service water heating
• Aftercooler (the manufacturer lists it as optional)
• Extended five-year warranty
• External variable-speed drive cabinet (standard at this size)

Where to look next

The most powerful machine of the whole series, and with stepless control on top of it. The drive stands in a cabinet of its own beside the machine. The fixed speed version is SCR-280 H, one size down SCR-250 HPM. For the workshop and lighter duty there is the smaller series SCR-APM Maxi.

Outputs, dimensions, weights and connections are stated by the manufacturer, the noise levels and order codes by the importer. The output is measured to ISO 1217, annex C. The figures hold for standard conditions; in heat, at altitude or in a dusty plant the machine has to be assessed separately. We reserve the right to make changes without notice — the order confirmation is what counts.