Direction within a casing closed at the ends by side plates. The impellers rotate, drawing air into one side of the casing and forcing it out of the opposite side against the existing pressures. The differential pressure developed, therefore, depends upon the resistance of the connected system.
Blowers, as positive displacement types, do not generate pressure within the casing; instead, the discharge pressure relies on the system resistance or back pressure. Maintaining small operational clearance achieves effective sealing of the compressor inlet area from the discharge area, eliminating the need for internal lubrication of the lobes. A pair of accurately machined alloy steel hardened and ground timing gears maintain clearances between the impellers, during rotation. The air, thus delivered, is 100% OIL FREE.A lobe compressor's pumping capacity, when operating at constant speed, remains unaffected by variations in inlet and discharge pressure. These Blowers are constant volume machines, which deliver a fixed discharge against the system backpressure. Therefore, it is essential to ensure that we impose minimum pipeline restrictions at the inlet and discharge. Adequate size piping and large radius bend ensure minimum line losses resulting in higher efficiency and low power consumption. We should also avoid sudden changes in the pipeline cross-section.
To change capacity, you must either adjust the speed (for energy saving) or release some of the air into the atmosphere (which is not energy saving). Avoid recirculating air from the discharge to suction to prevent overheating. Never try to control the compressor's capacity by throttle valves in the intake or discharge piping. This increases the power load on the motor and may seriously damage the compressor. There is an increase in the discharge air temperature due to the heat of compression. As a thumb rule the discharge air temperature increases @ 100C for every 0.1 Kg/cm2 of P above the inlet temperature.
