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Power Mizer® Cast Centrifugal Blowers


Power Mizer blowers represent the culmination of years of research and experimentation as Spencer engineers applied our Engineering Edge to the task of creating more energy-efficient, power-conserving cast blower technology.

The air handling components of these blowers were designed in the Spencer Development Laboratory. By avoiding abrupt velocity changes that create turbulence and waste energy, our engineers achieved smoother, more energy-efficient airflow from blower inlet to discharge.

In industries around the world, Spencer Power Mizer® multistage cast centrifugal blowers provide high efficiency air delivery in heavy-duty process applications such as:

  • Desulfurization processes
  • Wastewater aeration
  • Air knives
  • Hazardous vapor control
  • Soil remediation
  • Fluidized beds
  • Central vacuum systems
  • Felt dewatering
  • Landfill gas boosting
  • Combustion air delivery


Unique setup of Power Mizer blowers in series, driven by a single motor, delivers air for a high altitude test rig for automotive engines

In another prime area of usage, water and wastewater treatment, Power Mizer blowers serve demanding and non-stop applications such as:

  • Wastewater aeration
  • Sewage aeration
  • Odor control
  • Grit chamber aeration
  • Channel aeration
  • Filter backwash

Cast Components with Low Operating Sound Levels


The inlet section, return channels and discharge section of Power Mizer blowers are gray cast iron with excellent strength, chemical resistance and sound attenuation.

The rotor assembly of Power Mizer blowers in Series 4000 and larger contains cast aluminum impellers. Their three-dimensional blades transfer energy to the airstream with very high efficiency. Blade configurations include radial, backswept and combinations of both, selected by Spencer engineers using specialized computer software.

Superior Aerodynamics

Uniquely shaped impellers, return channels with airfoil-shaped vanes, redesigned inlet and discharge passages and vaneless diffusers all contribute to a peak adiabatic efficiency that is above 80%. The highest efficiencies are achieved without baffle rings at each stage. The result is a much simpler design with fewer parts.

Precisely Balanced Rotors

Spencer’s exacting balancing procedures produce an overall vibration level of 1.0 mil or less – the best in the industry. This decreases bearing stress, which improves bearing life and blower reliability.

Year-In, Year-Out Savings

Power Mizer blowers offer long-term power savings of tens of thousands of dollars per blower per year. And you can often downsize the motor to save even more!

Industrial Example:
(assuming savings of 38 HP for one blower).
38 HP x .746 = 28.348 kW saved.
28.348 x 24 hours x 365 days (continuous annual operation) = 248,328 kWH per year.
248,328 x $.10/kWH (local utility cost) = $24,832 annual savings.
Motor efficiency of 95% yields an actual savings of $26,139 on an annual basis.
Wastewater Treatment Example: A New England WWT utility replaced five positive displacement aeration blowers (aggregate 450 HP, 3500 SCFM) with three Power Mizer blowers (each 190 BHP, 4000 SCFM). Even with only one blower running at a time, the customer saves $7,000 per month in power bills and expects the blowers to pay for themselves in four years or less.

Power Mizer Product Range


  • Seven Power Mizer series, each of which can be designed with different types and numbers of impellers to meet precise airflow requirements. Get more product information in Technical Data Sheets (please note these are all PDF files).Series ,  and
  • Pressure to 28 psig (193 kPa); Volume to 35,000 icfm (991 m3/min); Power to 2000 hp (1491 kW).
  • Choice of oil or grease lubrication in Series 2500 and 3500; all others oil-lubricated.


Power Mizer Versatility and Capability Around the World


Power Mizer Series 6000 blower being readied for a “green” application to convert paper mill byproducts into usable process materials.

Working under difficult, dirty conditions inside paper mills, Spencer Power Mizer Series 6000 blowers are helping turn a waste product into a valuable papermaking ingredient. Our OEM customer builds processing plants within paper mills around the world. The blowers handle flue gas in a process that converts mill byproducts into calcium carbonate for paper whitening in place of hazardous chlorine.

To survive the unusually difficult environment, our blowers have special coatings, shaft seals, bearing seals and flushing provisions devised by Spencer’s R&D Department. The blowers are going into new systems and also replacing installed competitive blowers because they are more reliable and efficient, providing long-term cost savings.


For a municipal landfill gas handling application involving a highly corrosive and combustible “witches’ brew” of methane, carbon dioxide, oxygen, nitrogen and water vapor, Spencer engineered and supplied three Power Mizer Series 7000 blowers powered by 300-horsepower, 4160-volt motors. They have Heresite® coatings on major internal parts for corrosion resistance, a 3/8″ corrosion allowance (extra-thick housing walls), a highly unusual 304 stainless steel blower shaft and two belly wraps for quiet operation. The challenges in this case were so extreme, some of these provisions evolved during an extended period of experimentation and testing.


Power Mizer blowers for Indonesian refinery feature two special drive configurations: one has a motor and gear increaser for use with 50Hz electricity, the other has a steam turbine power source.

For an oil and gas refinery in Indonesia, Spencer supplied two Power Mizer degassing blowers, which provide a steady flow of air and hydrocarbons to a burner that disposes of byproducts generated during LPG (liquefied petroleum gas) and sulfur recovery. To meet the client’s unusual operating conditions, our blowers were adapted for use with non-standard power sources. One accepts 50Hz electricity and the other is driven by a steam turbine to serve as backup during power outages.


Massive Power Mizer Series 7000 blower with Acoustical Belly Wrap® before shipment to China for municipal wastewater aeration.

In the face of heavy international competition, Spencer won a highly coveted municipal wastewater treatment contract to serve a city of 4.5 million people in China. Power Mizer Series 7000 blowers were furnished along with electrical controls and mechanical accessories.  The system provides 40,000 cfm of air to the biological treatment process in 36 aeration basins through a network of fine bubble diffusers.

Power Mizer Accessories


Power Mizer with Acoustical Belly Wrap, an effective noise reduction device.
  • Standard and custom electrical control panels including UL and CUL Listed controls
  • Blower and motor protective devices
  • Valves and silencers
  • Gauges and instruments
  • Acoustical Belly Wrap™
  • Tubing and fittings of steel, stainless steel, galvanized steel and aluminum
  • Alternate drives – steam turbine, belt drive, VFD

Advanced Aeration Technology for Water and Wastewater Treatment


Power Mizer Series 5000 blower is part of high efficiency aeration system controlling dissolved oxygen in activated sludge lagoons at a WWT facility.   Complete air delivery system was designed and furnished by Spencer, including PLCs, VFDs, DO control logic, operator interface, modem communication software and blower protection devices.

Spencer can furnish complete, Power Mizer-based air delivery systems that are process-optimized, energy-efficient and totally integrated with these features:

  • Dissolved oxygen (DO) control systems including PLCs programmed with Spencer’s unique direct airflow control logic
  • Variable frequency drives with automated speed adjustment in response to DO changes
  • Motor control centers
  • Blower protection panels
  • Activated sludge diffusion systems
  • Aeration control system engineering