Rotary blower package DEFENDER™

positive-displacementlow-noisecompact

Overview
The HOFFMAN DEFENDER™ Screw positive displacement blower packages offer configurable, compact blower systems optimized for environmental and municipal aeration applications. Designed for reliable continuous or intermittent duty, the DEFENDER™ range delivers high air flow at reduced energy consumption thanks to an internal compression profile and patented rotor design.

Key Features

• Efficient — Patented rotor profile reduces required rotational speed and improves the capacity-to-pressure ratio.
• Quiet Operation — Internal compression, integrated silencers and optional noise-reducing enclosure minimize acoustic emissions.
• Simple — Easy installation and straightforward mechanical layout for rapid commissioning.
• Flexible — Wide turndown capability to match process demand and maintain operation at optimal efficiency.
• Ease of Maintenance — Robust, accessible construction reduces service complexity and downtime.
• Lower Operating Speed — Reduced rotor speeds compared with lobe blowers lower wear and noise.

Application: Municipal Wastewater Treatment
The DEFENDER™ screw blower range is engineered for aeration in wastewater treatment plants where energy costs are significant. The design provides maximum air delivery with minimum energy input and supports both continuous operation and frequent stop-start cycles. Pressure capability up to 14.5 psig enables feeding deep collection basins while keeping noise low.

Benefits and Performance

• Lower Life Cycle Costs — High efficiency across a broad speed range reduces energy consumption; durable construction and fewer parts extend intervals between services.
• Flexible Operation — Belt drive configuration allows matching delivered capacity to process requirements and supports intermittent use.
• Quiet Operation — Optimized rotor geometry, low rotor speed and absence of step-up gears, combined with silencers and enclosure options, reduce compression and radiated noise.
• Reliable — Component design and lower operating speeds improve reliability; integrated controllers enable continuous monitoring, remote diagnostics and predictive maintenance.

Technical Data (reference conditions)
Atmospheric air: absolute pressure 14.7 psi, temperature 68°F, relative humidity 36%
Flow tolerance: ± 5%
Maximum pressure capability: up to 14.5 psig

Related Assets
Performance curves, specification sheets and selection brochures are available for the DEFENDER™ series to support sizing and project specification.

Specifications

• Series name: DEFENDER™
• Maximum capacity: up to 6,180 cfm
• Maximum pressure capability cited: up to 14.5 psig
• Patented rotor profile for improved capacity-pressure ratio
• Internal compression to improve energy efficiency
• Expected energy savings versus alternative technologies: approximately 15%–30% (application dependent)
• Quiet design elements: low rotor speed, no step-up gear, silencers, optional noise-reducing enclosure
• Drive: belt drive to match required capacity and ensure operation at optimal efficiency
• Operational modes: suitable for continuous and intermittent (stop-and-start) use
• Flow tolerance: ± 5%
• Reference atmospheric conditions: 14.7 psi absolute, 68°F, 36% RH
• Maintenance: simple and robust construction for easy maintenance; controllers support remote diagnostics and predictive maintenance
• Typical application: municipal wastewater aeration and other environmental applications