All about Blowers Series: Blower Selection Examples

Although blowers are commonly used in manufacturing, it can be difficult to find good sources of information on the different types of blowers and how to choose the appropriate one. The purpose of this article series is to give a good, basic understanding of the different types of blowers and provide you with the technical information required to make a good decision for your application.

Recommended Reading

• Part 1: Impeller-based Blowers
• Regenerative versus Centrifugal Blowers
• Part 2: Positive Displacement Blowers
• Part 3: Blower Comparison Chart
• Flow, Velocity, and Pressure
• Part 4: Specialty Blowers
• Part 5: Important Design Parameters for Choosing a Blower

Blower Selection Examples

​In order to make the information in the previous articles more tangible let’s look at a number of scenarios and the thought process that might go into selecting a blower for each one.

Example 1

Application: A stamped metal part is covered in a layer of forming oil and the forming oil needs to be flashed off quickly before a secondary process can be completed. The blower must be paired with an air heater as the temperature required to flash off the oil at the required speed is significant. Due to its restrictive nature, the heater exerts significant back pressure. A slot type nozzle on the heater causes further constriction of air flow. Furthermore, the hot air must be moving at a high velocity out of the nozzle to achieve good impingement on the part surface maximizing heat transfer.
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Blower Selection: In this example, a centrifugal blower is eliminated because of the pressure drops associated with the heater and nozzle. The pressure required is likely in the range of 2-3 psi. Although the velocity required out of the nozzle is high, the associated volumetric flow is not. The operating pressure in this application is at the low end for a positive displacement blower, but is right in the sweet spot for a regenerative blower. 

Example 2

Application: A part is heated in a 5’ x 5’ x 5’ or 125ft3 oven maintained at 150°C. Due to energy loss and temperature uniformity requirements the chamber must be refreshed with air at the desired temperature 5-10 times per minute. An open coil heater with a low pressure drop is the best choice to provide the heat given the low temperature requirement.
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Blower Selection: The size of the chamber and number of air exchanges necessitates a high volume air flow rate. Additionally, the pressure drop across the air heater is not significant. As a result, a centrifugal blower is the best choice.

Example 3

Application: Air must be pumped into a liquid filled tank. The water level in the tank exerts a back pressure of 10 psi. The process requires airflow of 300CFM.

Blower Selection: The required operating pressure of 10 psi eliminates impeller based blowers for this application. In this case, the best choice is a rotary lobe blower to meet the flow requirements at this operating pressure.
As you can see, choosing the appropriate blower for an application can be a complicated process. We hope the knowledge you gained from this article series will help make the choice more straightforward.

If you have questions, please call STANMECH and we will be happy to help.