Regenerative Blower

regenerative blower

Improved Efficiency for Regenerative Blower Machinery

Introduction

The side channel, regenerative blower design has been a staple product for over fifty years in the industry. Continuous, pulsation-free volumetric flow is a unique characteristic of the regenerative blower, especially relative to reciprocating machinery. Furthermore, the side channel blower, compared to axial and radial machines, generates a substantial pressure ratio.

cross section side channel regenerative blower

A rotor disc accelerates all intake air, and after passing through the outer area of the side channel, it is transported through the circumference of the side channel into another chamber of the rotor disc. During the revolution of the rotor disc, this process is consistently repeated to build up the pressure. A large portion of this compressed air leaves the device at about half of a rotation. The rotor disc sends the other portion of air to the inlet of the device so it can mix with new, fresh air.

Although the production stage for this regenerative blower model series was already reached, optimizations are still possible and are important for enhancing efficiency. With some statutory requirements for drive optimization, improving the flow area will increase the efficiency of the blower.

Regenerative Blower Drive

New efficiency classes were introduced by the legislature, and they must be implemented by the users.

All motors with 0.75 kW or more need to have an efficiency rating of at least 77.4% (2-pole motor). For motors with higher power ratings, efficiency must reach at least 95.4%. This efficiency class IE2 (high efficiency) is the first step in significantly reducing a motor’s energy consumption. The values were further tightened after January 1, 2017. During these two phases, the minimum efficiencies will increase. In the first phase, the minimum is pushed up to 95.8%, based on a 2-pole motor, and will be required for any motors with shaft power ratings of 7.5 kW and higher. On January 1st, 2017, smaller motors with power of 0.75 kW and above were required to meet the values of efficiency class IE3 (premium efficiency). However, there is an alternative option to equip motors with an electronic speed control in conjunction with the IE2 motors.

efficiencies of regenerative blower motors

The regenerative blower motors are improved by increasing the quality of materials and making geometric modifications such as motor size and package length. This typically means high production costs, but these costs tend to be quickly covered by the significantly lower operating costs. Regardless, it can be difficult to maintain success in a market with these costs.

 

In addition, relative to side channel blower efficiency, motor efficiency is already high; therefore, it is paramount for the hydraulic and volumetric efficiency of the compressor to reach a substantial reduction of power consumption. Any increased motor costs, however, should be compensated by a further optimized side-channel blower. This drive represents a large proportion of the total costs with regenerative blower, and it can be difficult to maintain a low cost while also improving overall efficiency. The regenerative blower can be used at a variety of operating points; therefore, it is paramount to reach the greatest possible efficiency across all possible applications because the device load will change with each operating point as well as the efficiency.

Device Concept

3.1 Stages

Double-sided rotor discs are common in many regenerative blower designs, and they can be used for two-flow or two-stage configurations. With two-stage operations, the pressure ratio is increased at the expense of volume flow. The geometry of the rotor disc must guarantee that the two halves of the rotor disc are completely sealed off from each other. For a double-flow operation, however, the volume flow is increased by lowering the possible pressure ratio. This allows the device to be adjusted to each customer’s operating point while using most of the same parts, increasing overall efficiency.

3.2 Flow Route

Geometric specifications of the main dimensions are a pivotal aspect of reaching an optimal design for a regenerative blower. The basic parameters of the geometry are defined through a proper combination of rotor disc outside and inside diameter, length and design of the interrupter, number of blades, blade angle, etc. After these values have been defined, flow channels, including the inlet and outlet, are designed so the pressure build-up can take place in a controlled manner. 3D CAD software ensures the channels are optimized. Using a computational fluid dynamics (CFD) simulation, the effectiveness of the geometries is tested. In this simulation, the regenerative blower represents a complex, transient computational model.

This approach has the advantage of ensuring the optimizations produce the proper result before the first models have been created, rendering numerous prior tests unnecessary.

The next step is to fully realize the resulting parts using casting production methods. Some designs cannot be used or are associated with higher costs, depending on the casting process. Certain compromises must be made when both costs and flow optimization are considered.

Another important aspect for the optimal design of the regenerative blower is the size of gaps between moving and static parts. Depending on the casting processes, different manufacturing tolerances can be achieved. Die casting is most commonly more accurate than sand casting. The manufacturing tolerances for the subsequent device are also significant. These larger tolerances, and larger gaps between parts, cause greater losses. This has a substantial effect on the overall efficiency of the regenerative blower. Therefore, the goal is to keep the tolerances as small as possible and maintain reasonable production costs and reliable production processes.

Adjusting the Speed to Change the Point of Operation

regenerative blower Side chennel with integrated converter

For contact-free turbomachinery, a regenerative blower is best suited for operation with variable speeds. This allows for increasing the power density by increasing speed, typically up to 100-120 Hz. It is also possible to adapt the speed and the volumetric flow to each customer’s needs.

The device’s characteristics make it applicable in a wide range of operating conditions at a reasonable efficiency without losses from blow-off valves or throttles. A frequency converter can also be integrated into the drive for more user-friendliness.

Design of the Regenerative Blower

As opposed to devices built early on, design plays an incredibly important role. Efficiency-optimized designs must not have a negative impact on the flow route. This means the design has limitations with respect to the outer shape of the device. Overall, it represents a good compromise between appearance and optimal function.

Summary

When all these aspects are put together, it leads to a new, optimized regenerative blower. This blower consumes much less power at a comparable operating point. Optimizing individual components of a regenerative blower makes it possible to achieve major improvements, even for devices that have been around for some time.

There are many positive side effects to this process. These include the reduction of both weight and size and improving the ease of integration. This conserves resources and has a positive effect on the energy performance of the regenerative blower. The optimized flow route is also a positive effect on the noise the device produces. Normally a large amount of flow noise is created, this has been significantly reduced in the newly designed regenerative blower.

 

 

The Becker Regenerative Blower for Vacuum

Single stage blowers for vacuum feature:

  • 100% oil-less operation
  • Quiet
  • Compact
  • High performance
  • Integrated inlet filter
  • Integrated vacuum relief valve
  • Contact-less
  • Minimal maintenance
  • Convertible to two stage operation

Two stage blowers for vacuum feature:

  • 100% oil-less operation
  • Quiet
  • Compact
  • High performance
  • Integrated inlet filter
  • Integrated vacuum relief valve
  • Contact-less
  • Minimal maintenance
  • Convertible to single stage operation

Variair Regenerative Blowers for Vacuum

  • 100% oil-less operation
  • Patented intelligent variable speed controller
  • Quiet
  • Compact
  • High performance
  • Integrated inlet filter
  • Contact-less
  • Minimal maintenance
  • Maintains constant vacuum level

The Becker Regenerative Blower for Pressure

Single stage blowers for pressure feature:

  • 100% oil-less operation
  • Quiet
  • Compact
  • High performance
  • Integrated inlet filter
  • Integrated pressure relief valve
  • Contact-less
  • Minimal maintenance
  • Convertible to two stage operation

Two stage blowers for pressure feature:

  • 100% oil-less operation
  • Quiet
  • Compact
  • High performance
  • Integrated inlet filter
  • Integrated pressure relief valve
  • Contact-less
  • Minimal maintenance
  • Convertible to single stage operation

Variair Regenerative Blowers for Pressure feature:

  • 100% oil-less operation
  • Patented intelligent variable speed controller
  • Quiet
  • Compact
  • High performance
  • Integrated inlet filter
  • Contact-less
  • Minimal maintenance
  • Maintains constant pressure

 

To learn more or to discuss what type of regenerative blower is right for you, contact Becker Pumps.

Save

Save

Save

Save

Save

Save

Save

Save

Save

Save

  • NEW Regenerative Blowers

    New Lower Price • Better Performance
    Lighter Weight • More Compact Design

    Learn More
  • NEW Genuine Parts

    Extend the life of your pump with genuine replacement parts.

    Learn More