Selecting a Regenerative Blower for Process Heater Applications

Regenerative blowers are portable, low-pressure air sources that are ideal for use with many Tutco SureHeat Air Heaters. They provide inexpensive, clean, oil free air, and can be easily mounted on equipment.
 
A blower must be able to provide your desired amount of flow even with the restrictions caused by the heater, plumbing, and manifolding. These restrictions can reduce the amount of flow to your process, and, if severe enough, can cause the blower motor to overheat and become damaged.
 
Selecting the right blower is easy. Just follow the simple steps below: 

Step 1: Determine Heater Back Pressure
The amount of back pressure caused by the heater is found by looking at the dotted lines on the heater Performance Curve found in the Operating Instructions. The amount of back pressure in PSI or Inches of Water (27.7 inches of Water = 1 P.S.I.) depends on the heater operating temperature and desired airflow, Standard Cubic Feet per Hour (SCFH). 

Step 2: Determine Blower Capability
Blower manufacturers provide performance curves for various size blowers. The maximum output of the blower is based on zero exit restrictions (zero pressure). In the example below, this is a 27 CFM-rated blower. Note how the blower output (CFM) decreases with increasing back pressure (Inches of Water). Also note that blower output is lower at 50 Hz operation. 
 
Using the blower curve, verify that the blower chosen can generate sufficient flow (for your process), for your expected back pressure.

Remember, additional restrictions can add to the back pressure seen by the blower. Therefore it is better to choose a slightly larger blower, rather than a smaller one, like in our example. Excess flow can be diverted upstream of the heater using a bleed valve, or you can buy a variable speed blower which is easy to adjust, but is more expensive.
 
Heaters with openings smaller than 1” NPT are not recommended for use with blowers. The SureHeat JET, SureHeat MAX, Serpentine VI, 2-1/2” Inline, and Flanged Inline are suitable for use with blowers. 
 

Example (reference charts below): 
 
A manufacturing process using a Serpentine VI heater #F040292 with housing #F057088 requires 10 SCFM (600 SCFH) of flow at 1000°F.
 
Step 1: Determine Heater Backpressure
At this flow and temperature, the heater will produce approximately 20” H2O (0.72 PSI) of backpressure.
 
Step 2: Determine Blower Capability
At this back pressure value, the blower will output approx. 15.0 CFM, sufficient to meet our 10 CFM requirement.