Double stage series roots blower (two roots blowers are used in parallel)

Under some working conditions, single blower equipment may not meet the actual application of air volume and pressure performance. Without considering the performance improvement of single equipment, joint operation (series or parallel) can be used to make up for the lack of performance of single equipment.

How do the performance parameters change when roots blowers operate in parallel or series?

When multiple roots blowers work at the same time, the series connection is mainly used to increase the pressure, while the parallel connection is mainly used to increase the flow. But the performance of Roots blowers when working together is not simple superposition.

As shown in the figure:

Among them, when in parallel, multiple roots blowers will supply air to the same pipeline. Generally, when Roots blowers are connected in parallel, the same type of equipment with the same performance parameters will be used. At this time, the total air volume will be greater than the air volume of a single fan, but less than the sum of the air volumes of all parallel devices (for example, the air volume of two parallel devices will be slightly less than the air volume of a single fan), and the pressure will be basically equal to the air volume of a single Roots blower (will increase). The specific performance change is related to the pipe characteristic curve. If equipment of different models and different revolutions are connected in parallel, the situation is similar to the above, but at this time, the equipment with lower performance may have a small output air volume, even when the total flow is reduced, it cannot be transported. Therefore, blower devices of different types and parameters are connected in parallel, so the situation is complex and seldom used.

Practical operation of two-stage series roots blower:

Under some working conditions, the air volume and pressure performance of a single Roots blower may not meet the actual application. Without considering the performance improvement of a single unit, multiple fans may work together (in series or parallel) to make up for the performance deficiencies of a single unit.

How do the performance parameters of Roots blower change when it works in parallel or in series?

When multiple roots blower equipment work together, the series connection is mainly for pressurization, while the parallel connection is mainly for increasing flow. However, the performance of Roots blower in joint operation is not a simple superposition.

As shown in the figure:

In parallel connection, multiple roots blowers supply air to the same pipeline. In general, roots blowers in parallel will use equipment of the same model and performance parameters. At this time, the total air volume will be greater than the air volume of a single blower, but less than the sum of the air volume of all parallel devices (for example, two parallel devices, the air volume will be slightly less than twice the air volume of a single blower), and the pressure is basically equal to the pressure of a single roots blower (will increase). The specific performance change is related to the pipeline characteristic curve. If the equipment with different models and different revolutions are connected in parallel, the situation is similar to the above, but the equipment with lower performance may have little output air volume or even cannot deliver when the total flow is reduced. Therefore, blower equipment of different models and parameters are connected in parallel, which is more complicated and seldom used.