Comprehensive engineering benchmarks, aerodynamic trade-off analysis, and OEM customization guidelines for global procurement directors & HVAC design engineers.
When global HVAC system architects, medical ventilation engineers, and industrial OEMs evaluate forced-air movement solutions, the decision matrix frequently hinges on a primary physical constraint: maximizing volumetric airflow (CFM) within restricted cabinet envelopes without exceeding acoustic noise thresholds.
A Double Inlet Centrifugal Blower (also known as a Double Inlet Double Width or DIDW blower) resolves the fundamental fluid dynamic bottleneck inherent to Single Inlet Single Width (SISW) configurations. By integrating a dual-eye impeller housed inside an expanded volute casing, air enters simultaneously from both lateral sides of the blower housing along the motor axis.
This symmetrical air intake doubles the total inlet throat area. Under standard fluid mechanics principles ($Q = A \times V$), expanding the throat cross-sectional area ($A$) allows the blower to draw significantly higher air volumes ($Q$) at lower intake velocities ($V$). Lower intake velocity directly translates to reduced aerodynamic turbulence, minimized eddy currents at the blade tips, and a marked reduction in operational sound pressure levels (dB(A)).
At Delco Fans Pvt. Ltd., our shop-floor testing across five decades confirms that a properly engineered double inlet forward-curved blower delivers up to 85% more airflow capacity than an equivalent-diameter single inlet blower, while operating at identical motor rotational speeds (RPM) and maintaining a compact height profile.
| Engineering Parameter | Single Inlet Blower (SISW) | Double Inlet Blower (DIDW) | OEM Application Benefit |
|---|---|---|---|
| Air Intake Mechanics | Single lateral suction eye | Dual symmetrical suction eyes | Eliminates axial shaft thrust loading & turbulent inlet starving |
| Volumetric Airflow (CFM) | Baseline (100%) | 165% – 190% of SISW baseline | High-volume air movement in height-constrained HVAC units |
| Static Pressure Capability | High static pressure spike capability | Moderate-to-high sustained static pressure | Optimal for ducted systems, air curtains & multi-stage filters |
| Acoustic Output (dB(A)) | Higher inlet velocity vortex noise | 3 dB(A) to 6 dB(A) quieter at equal CFM | Essential for medical equipment, cleanrooms & indoor HVAC |
| Motor Load Balance | Asymmetrical radial & axial forces | Symmetrically balanced air loading | Extends bearing L10 service life beyond 40,000 continuous hours |
| Dimensional Envelope | Narrow width, high wheel diameter | Wider axial footprint, reduced height | Low-profile ceiling cassettes, fan coils & air handlers |
Delco Fans engineers application-specific variants engineered around defined duty cycles, electrical supply profiles, and static pressure curves. Explore our primary double inlet product lines below.
Engineered with galvanized steel or electro-coated scroll housings and double-width forward curved impellers. Powered by continuous-duty AC Shaded Pole or FHP induction motors.
CFM Range: 250 – 2,200 CFM | Pressure: Up to 450 Pa
Incorporating Electronically Commutated (EC) brushless DC drives with integrated drive electronics. Delivers stepless 0-10V/PWM speed control and high energy savings.
CFM Range: 400 – 3,500 CFM | Efficiency: IE4 / EC Premium
Direct-drive motor mounting inside the scroll airstream provides self-cooling motor operation, eliminating drive belts, pulleys, and side-load bearing wear points.
Voltage: 110V - 415V AC | Dual-Plane Balanced
Custom fabricated scroll housings with specialized mounting flanges, vibration isolation grommets, and Class H insulated copper windings for high ambient heat operation.
Temp Rating: Up to +80°C Ambient | Sealed Ball Bearings
Procurement leadership requires anticipating technological shifts, regulatory mandates, and supply chain transformations. The global air handling and blower manufacturing sector is undergoing four pivotal transitions:
Global environmental regulations (EU ErP Directive, US DOE fan efficiency standards) are forcing OEMs to phase out low-efficiency belt drives and PSC motors. Direct-drive EC Double Inlet Blowers deliver partial-load energy savings reaching 30% to 50%, enabling equipment compliance across international markets.
Traditional belt-driven blowers suffer from friction losses, belt dust contamination in cleanroom environments, and mandatory retensioning maintenance schedules. Direct-drive double inlet configurations integrate internal motors directly into the impeller hub, eliminating mechanical transmission loss and reducing total maintenance downtime.
Global OEMs are diversifying component sourcing away from single-country reliance. India’s precision motor and blower manufacturing sector—led by established plants like Delco Fans in Thane—offers high-grade electrical steel laminations, certified copper windings, robust quality control, and competitive Total Cost of Ownership (TCO).
As commercial HVAC and medical devices migrate closer to living and working quarters, dB(A) ratings become decisive purchasing criteria. Computational Fluid Dynamics (CFD) designed forward-curved blade profiles combined with double-inlet housing geometry suppress tone frequencies and reduce air turbulence noise.
Modern HVAC units require active communication with Building Management Systems (BMS). Next-generation EC double inlet blowers incorporate RS485 / Modbus RTU telemetry, allowing real-time monitoring of blower speed, motor operating temperature, power consumption, and predictive maintenance alerts.
To eliminate expensive chassis redesigns, global OEMs require blower suppliers to build custom mounting footings, discharge flanges, and wiring harnesses that match legacy footprints. Modular housing tooling at Delco Fans allows rapid prototype turnaround without heavy tooling re-investment.
Correctly matching a Double Inlet Centrifugal Blower to an OEM application requires evaluating four interrelated thermodynamic and aerodynamic variables:
| Blower Model | Max Airflow | Max Static Pressure | Voltage / Freq | Motor Type |
|---|---|---|---|---|
| DEL-DIDW-130 | 450 CFM | 280 Pa | 230V / 50-60Hz | Shaded Pole / PSC |
| DEL-DIDW-160 | 850 CFM | 380 Pa | 110V - 230V AC | AC FHP Induction |
| DEL-DIDW-180-EC | 1,450 CFM | 520 Pa | 230V EC Direct | Brushless EC Motor |
| DEL-DIDW-200 | 2,100 CFM | 600 Pa | 230V / 415V AC | 3-Phase Induction |
| DEL-DIDW-250-EC | 3,600 CFM | 750 Pa | 230V / 400V EC | EC Premium Direct |
Answers to critical questions asked by global OEM buyers, mechanical design engineers, and supply chain managers.
Founded in 1974 in Wagle Industrial Estate, Thane, Maharashtra, Delco Fans Pvt. Ltd. brings over five decades of continuous shop-floor manufacturing and application engineering experience to the global movement of air and motion drive technology.
Unlike catalogue traders or assembly-only outfits, Delco maintains complete end-to-end control over our manufacturing processes: in-house motor lamination punching, automatic coil winding, rotor die-casting, scroll housing sheet metal press tooling, dual-plane dynamic balancing, and automated test benches.
“Sourcing Double Inlet Centrifugal Blowers from Delco Fans has significantly enhanced the performance of our commercial fan coil units. Their engineering team customized the scroll housing mounting flange to match our exact drop-in cabinet footprint, and the low noise signature exceeded our acoustic specifications.”
“Delco’s in-house manufacturing capability is evident in every batch. Their double-inlet EC blowers provided our cleanroom ventilation systems with exceptional motor efficiency, quiet operation, and zero field failures over three years of continuous 24/7 production duty.”
Provide your target airflow (CFM), system static pressure, voltage requirements, and physical dimensions. Our engineering team in Thane will review your specification and provide a comprehensive proposal.