In layman's terms, a blower is a device which increases the velocity of air that is passed through it. Effectively, a blower is designed to move air and gas at low to high pressure to perform a specific function. Blowers serve a broad spectrum of applications in a variety of industries, including: cooling, conveying, ventilating, exhausting, etc. Blowers are typically used when the pressure requirement falls somewhere between that of a fan and that of a compressor.
Blowers work by way of an increase in pressure of either air or gas through the centrifugal movement of a rotor. The blower takes in air/gas via an inlet valve, which causes the impellers (or rotors) to rotate, which creates a centrifugal force which propels the air or gas. While this occurs, the air/gas is continuously compressed with a linear increase in pressure.
There are four main types of blowers. Each of these have their various advantages and disadvantages, and are used for specific functions:
Positive displacement blowers, which are suitable for applications which involve either air or neutral gas, operate in a relatively simplistic fashion. Air or gas enters through a section on one side of the blower which increases in size and exits through the other side which decreases in size. Due to the difference in proportion between the entry and exit points, positive displacement of the air occurs as it is released through the contracting side, increasing air pressure. A particular feature of this kind of blower is that regardless of pressure changes, the speed of airflow remains consistent.
One specific kind of positive displacement blower is the rotary lobe blower. This operates by way of dual rotors which rotate in opposing directions. The blower draws in air, and the lobes spin the air around before impelling it outward.
Due to the rotary lobe function, these blowers produce a high volume of air, and thus are useful for larger vacuum systems. As these types of blowers are used for applications such as aeration tank deoxygenation, the air pressure generated is quite moderate (roughly 15 psi).
Helical screw blowers, much like centrifugal blowers, are able to produce air at higher pressures than rotary lobe blowers. Helical screw blowers utilize two rotors, which are each equipped with lobes (usually two or three). The main rotor fits into the flute of a second rotor.
A helical rotor is designed to give higher and more precise pressure due to the unique helical shape of the lobes on the rotor; the helical geometry works in such a way that it squeezes the air between the rotors. These rotors are also carefully aligned to avoid any contact between the lopes.
At Gardner Denver, we offer a wide range of blower products in various configurations. Visit our Product Page to discover our full range of products and learn more about how our blower technologies and designs can best suit your application needs.
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