Pasifik Two-Lobe Roots Blowers are positive-displacement machines engineered for the continuous and reliable transfer of air and process gases. Designed for demanding industrial operating conditions, the PB Series combines proven two-lobe rotor technology with robust mechanical construction, predictable performance and straightforward maintenance.
The series provides an efficient solution for industrial applications requiring stable volumetric flow, oil-free gas handling and dependable operation across a broad range of differential pressures.
Two-Lobe Models at a Glance
Roots Blower Body
Roots Blower Package
Roots Blower Unit
How Two-Lobe Roots Blowers Work
Two-lobe Roots blowers are rotary positive-displacement machines that move a defined geometric volume of gas during each shaft revolution. Two lobed rotors rotate in opposite directions inside the casing and are synchronized by an external timing-gear set. During normal operation, the rotors do not contact each other or the casing; precisely controlled internal clearances provide the necessary separation.
As each rotor passes the inlet, a pocket of gas is trapped between the rotor and casing and carried toward the discharge port. There is no significant internal compression within this trapped volume. The pressure rise occurs when the pocket opens to the discharge side and meets the back pressure created by the connected system. A Roots blower therefore moves volume, while the installation determines the differential pressure the machine must overcome.
At a fixed speed, theoretical displacement remains nearly constant. Actual delivered flow is lower because of internal leakage, commonly called slip. Slip generally increases as differential pressure and gas temperature rise. Performance must therefore be taken from the relevant model curve rather than calculated from speed alone. The selected operating point must also remain within the limits for speed, absorbed power, differential pressure and discharge temperature.
The compression chamber of Pasifik two-lobe Roots blowers is oil-free under normal operating and maintenance conditions. Lubrication is still required for the timing gears and bearings located outside the gas chamber. Oil-free compression must not be interpreted as an entirely oil-free machine, and applications with strict gas-purity requirements should be reviewed separately.
Reliable Positive-Displacement Performance
Two-lobe Roots blowers transfer a defined volume of gas during each rotor revolution. The delivered airflow is therefore primarily determined by blower displacement and operating speed, while the discharge pressure is generated by the resistance of the connected system.
This operating principle enables the PB Series to provide consistent airflow under changing process conditions. Unlike dynamic compressors, Roots blowers maintain a relatively stable volumetric capacity as system pressure varies within the approved operating range.
The two synchronized rotors operate without contacting each other or the blower casing. Timing gears maintain the required internal clearances, while the bearings and gears are lubricated outside the compression chamber. This arrangement prevents lubricating oil from entering the process gas under normal operating conditions.
PB Series Performance Range
Pasifik designs and manufactures its PB Series in Konya, Türkiye. Close control of machining, assembly and production keeps technical selection connected to manufacturing practice and operating feedback.
The current two-lobe range comprises PB100, PB112, PB125, PB137, PB151 and PB161 models, covering different flow, pressure, speed and power requirements. Model-specific limits must always be confirmed from the applicable performance data.
Across the complete series, available performance covers approximately:
- Inlet airflow: 36 to 7,750 m³/h
- Differential pressure: 100 to 1,000 mbar
- Operating principle: Positive displacement
- Compression chamber: Oil-free
- Flow control: Blower speed adjustment or variable-frequency drive
Actual capacity, absorbed power, discharge temperature and permissible blower speed depend on the selected model, operating pressure and inlet conditions.
Published performance data are based on reference inlet conditions of 1.0 bar absolute pressure, 20°C inlet temperature and 1.2 kg/m³ air density, unless otherwise specified.
Designed for Continuous Industrial Operation
Pasifik Twin-Lobe Roots Blowers are suitable for continuous-duty applications where mechanical reliability and process stability are critical. Their non-contacting rotor design minimizes internal wear, while accurately synchronized timing gears support stable operation throughout the approved speed range.
Correct blower selection ensures that rotor speed, absorbed power, discharge temperature and pressure remain within the permitted operating limits. The blower should therefore be selected according to the required inlet flow and differential pressure rather than by connection size or motor rating alone.