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PD Blowers & Vacuum Pumps

Blocker & Wallace Service LLC is an industry leader in providing positive displacement blowers and vacuum pumps for the manufacturing industry. We are a Gardner Denver Factory Authorized Distributor, repair and warranty center for PD blower lines, including Sutorbilt, DuroFlow, Drum, CycloBlower, HeliFlow, TriFlow and Elmo Rietschle. PD blowers can also be used as vacuum pumps by operating the unit from the blower's intake port. Shop our complete lineup of Gardner Denver PD blowers and find the positive displacement blower you need.

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How Rotary Positive Displacement Blowers Work

How Rotary Positive Displacement Blowers Work

Rotary positive displacement blowers typically use a straight lobe rotor design with two or three lobes. Advanced twisted rotor lobe profile designs are also used in certain applications.

PD blowers have twin rotating rotors (1 and 3) timed to turn in unison, creating a "positive displacement of air." The rotors achieve this by pulling air in through an intake port (A), filling a cavity formed by the rotor body and housing chamber (B).

The rotating lobe then carries this "air pocket" around the housing chamber (2) and forces it out of the discharge port (C), hence the term "positive displacement of air."

PD blowers use load resistance or back pressure to produce actual "air pressure" for conveying bulk products. The resistance is typically created by the product being conveyed. In reality, a positive displacement blower has to have a resistance to develop a significant pressure reading.

PD Blower Intake Path A - Intake air (yellow)
B - Air pocket
C- Discharge air (red)

Blower Parts:
1 - Drive rotor
2 - Housing chamber
3- Driven rotor

Frequently Asked Questions About PD Blowers

At Blocker & Wallace, we're proud to be a Gardner Denver Factory Authorized Distributor of positive displacement air blowers. Read these questions to learn more about PD blowers and our services.


What Is the Difference Between a Positive Displacement Blower vs. a Centrifugal Blower or Regenerative Blower?

In discussing a PD blower vs. a centrifugal or regenerative, the essential thing to understand is the effect produced by changes in pressure. A positive displacement air blower creates a more constant output flow regardless of the change in pressure, while a centrifugal blower's output varies based on changes in the operating pressure. As with centrifugal blowers, changes in the operating pressure affect the output of regenerative blowers.


Does Blocker & Wallace Offer a Warranty on Rebuilt PD Blowers?

Yes, we offer a warranty on rebuilt PD blowers that's good for one year after the build date.


What Standard Repairs Do You Provide for Positive Displacement Blowers?

Whether your blower has a tri-lobe or a twin lobe, our standard repairs for positive displacement blowers start with a factory-supplied overhaul kit with seals, bearings, shaft spacers, gaskets and shims. Other standard repairs include new oil sight gauges, oil sump breathers and lubrication fittings, plus much more. See our PD Blower Repair Services page for full details.

PD Blower Applications

Thanks to their ability to prevent blockages, PD blowers are used in numerous industries. Other PD blower advantages are a large volume of flow range, simpler handling, shorter lead times and lower life-cycle costs. Positive displacement blower applications include:

  • Aeration for aquaculture activities
  • Fluidization and conveying for cement and lime handling
  • Vacuum processing and transferring of chemicals
  • Methane gas recovery in coal beds and landfills
  • Automated milking in dairies
  • Fly ash conveying and aeration in power generation plants

Trust Blocker & Wallace for All Your PD Blower Needs

Blocker & Wallace has the expertise and industry knowledge to provide for all your positive displacement blower requirements. We specialize in new and remanufactured PD blower sales, consulting, system design, PD blower packages and blower repair.

About Blocker & Wallace

Backed by over 100 years of combined industry experience, Blocker & Wallace is the go-to source for PD blowers. As one of the few distributors authorized to repair and market all PD blower lines operated or owned by Gardner Denver, we offer unparalleled service and exceptional value. Our 57,000-square-foot facility features an in-house machine shop and fabrication shop as well as a large stock of new and remanufactured blowers and parts. Our experienced sales staff and factory-trained service technicians are ready to help with all your PD blower requirements.

About Gardner Denver

Gardner Denver is one of the world's biggest vacuum pump and positive displacement blower manufacturers. As a leading PD blower manufacturer,  Gardner Denver offers a wide range of mission-critical flow control and compression equipment and associated aftermarket parts. Starting as a small business in Quincy, Illinois, Gardner Denver has grown into a diversified, worldwide corporation. The positive displacement blower manufacturer prides itself on its engineering heritage, which spans more than 160 years. Gardner Denver's disciplined performance culture and intense customer focus support its vision of being the first choice for innovative and application-critical flow control products.

Purchase Your PD Blowers From Blocker & Wallace

When you're looking for durable, dependable PD blowers for sale, you're looking for Blocker & Wallace. You can rely on us for all your PD blower sales and service needs. Start shopping today for the positive displacement blowers that meet your requirement

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