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Today many industries and factories are using heavy machinery for their business. These are used for cleaning of sewage, ventilation, and supply of cement. Since most of the work is done by machines. Therefore it becomes important to find a variety of technology for different purposes.
In general, a blower is used to transfer air or gaseous molecules from one place to another. It is further subdivided into two categories that are centrifugal and positive displacement.
What is a Positive Displacement Blower?
A positive displacement blower is based on the momentum principle. In this, air molecules are driven from the inlet vacuum chamber to the outlet chamber by a high-speed force.
Mostly, these molecules get entrapped in the low-pressure zone. Further, the transformation of the gas is due to the pressure difference in both the inlet zone and the outlet zone. The inlet chamber has low pressure compared to the outlet.
Working of Positive Displacement Blower
The main component of the mechanism is the two rotors that are connected to the gears and enveloped by the blower casing. These rotors are also known as an impeller. Hence, the main parts which are used for the functioning of the positive displacement blower are impeller, blower casing, inlet, and an outlet chamber.
During its operation, the two rotors rotate at the same speed in the opposite direction. The first rotor is known as a driving rotor while the opposite one is called the driven rotor. This is because the first one is driven by the external power supply and the opposite rotor is run by the gears that are connected to the driving rotor.
When the impellers start, the air gets to flow into the inlet by the driving rotor and gets confined between the rotors and the blower casings. It further increases the pressure in the air molecules, as soon as the rotor moves and the outlet direction gets open, these molecules get pushed off from the chamber by a high force.
Types of Positive Displacement Blower
In general, it is designed as a straight lobe rotor to allow the gas to pass from the inlet and then discharged from the outlet. These straight lobes are also designed as two lobes or three lobes. The two lobes design is known as twin lobes whereas the three lobes design is called tri-lobe blower .
Twin Lobe Blower-
The twin lobe blower consists of two rotors for driving air. The amount of air enters the inlet is the same as the amount of air exit from the outlet. However, this is an old method and hardly used today. The maximum capacity of these roots is around 10,000 m3/hr. Therefore, it requires higher technology as well as gigantic rotors.
Tri-Lobe Blower-
The tri-lobe blower is designed by using three rotors for the air-driven process. The working principle is quite the same as the twin lobe blower. But, its life span is 15% more and also has a higher pulsation. This is the latest technology which is used everywhere.
Application of Positive Displacement Blower
In particular, the positive displacement blowers work more powerful in low vacuums and pressure. Even at high volumes, the pressure required is low. Henceforth, they are widely used in many industries. These industries may include aquaculture, oil and gas collection, chemical vacuum conveying, chip conveying, sewer cleaning, and material vacuuming.
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