Hitachi scroll air compressors

Depending on the size (2.2 to 22 kW), Hitachi scroll compressors have one to four heads.

Each compressor head consists of an oil-free compression chamber with a scroll element generating compressed air. In the event that one of the compressor heads is taken offline, the machine is able to continue operating with the remaining heads. According to the company, this design extends the scroll life.

Hitachi scroll compressors offer two modes of operation: standard pressure control, which is similar to conventional pressure switch, and multidrive mode. Under pressure switch control (P-mode), the compressor stops operating when reaching the maximum pressure and restarts when the pressure drops to the specified recovery pressure.

In multidrive mode, operation of the compressor heads is modulated automatically, matching air supply to the need of the compressed air. The delivery pressure is controlled by the quantity of the working heads, meaning that pressurising to the maximum pressure is not necessarily required and energy is saved. For example, a 15 kW unit, running at 50% capacity, will use 36% less energy compared to unload type.

Scroll compressors can be installed flush on the back and right-hand sides, saving space. They output little noise and vibration; according to the company, the scroll compressor is as loud as a person talking or whispering, depending on the size.

The oil-free operation gives better air quality and means used oil disposal is not required. In selected models, the option of 1 MPa discharge pressure is available.