How do I select a DE model from CFM and static pressure?

A centrifugal fan must be sized where your calculated system resistance intersects the fan curve. Do not select based on the catalog maximum CFM, because that represents free-air delivery at 0" SP (zero resistance). For example, if your duct network requires 2,000 CFM at 1.5" SP, refer to the DE350 or DE400 curves to confirm the exact operating speed, motor power, and sound rating.

Are maximum CFM and maximum pressure simultaneous?

No. Maximum CFM occurs at 0" static pressure (wide-open discharge), while maximum static pressure occurs at shut-off (0 CFM, fully closed discharge). As airflow increases through the duct network, static pressure drops along the fan curve. Operating points always lie between these two extremes.

Is the standard DE blower approved for restaurant grease exhaust?

Standard DE blowers are clean-air rated. Restaurant kitchen grease exhaust requires specialized configuration: belt-drive assembly with the motor isolated outside the grease-laden air stream, continuous full-seam welded liquid-tight housing, an access door for duct cleaning, a bottom drain plug, and compliance with local municipal codes and NFPA 96. For standard kitchen grease hoods, we recommend our certified Upblast Roof Fan series.

Is it approved for high-temperature or explosive gas?

Standard DE blowers are not certified for explosive atmospheres (ATEX/IECEx) or combustible dusts. Explosive gas service requires an explosion-proof certified motor, non-sparking aluminum or brass construction, and static-grounded drive belts. High-temperature gas applications require written factory configuration including cooling discs, high-temperature shaft seals, and Class H motor insulation.

Which models have verified 220V/60Hz or 380V/60Hz data?

The 60Hz catalogue validates: DE250 (1.5 HP), DE270 (2.0 HP), DE350 (3.0 HP), and DE400 (4.0 HP) with dual 220V/60Hz or 380V/60Hz ratings. Larger models DE300 (3.0 HP), DE400L (5.5 HP), DE450 (7.5 HP), DE500 (10 HP), DE550 (15 HP), and DE600 (20 HP) are strictly rated for 380V/60Hz three-phase power.

What housing materials and outlet orientations can be supplied?

DE blowers can be supplied in heavy-gauge carbon steel (-Q) with electrostatically applied baked powder coating (black), or stainless steel (-S) for moist and mildly corrosive industrial air. The scroll housing can be oriented at 0°, 90°, 180°, or 270° discharge angles in either clockwise or counter-clockwise rotation to match duct design.

DE Centrifugal Blower SeriesMedium Pressure: Up to 7.4" SPVerified 60Hz Models

Industrial Centrifugal Blower

DE-series centrifugal blowers for ducted ventilation, process air supply, and equipment booster systems. Engineered for medium-pressure ductwork with direct-drive (DE-A) and belt-drive options, delivering 1,595 to 13,765 CFM across 10 verified 60Hz models.

DE Industrial Centrifugal Blower

Request Duty Point Selection Call Technical Sales Download 60Hz Catalogue (1.8 MB)

Engineered medium-pressure ducted airflow (up to 7.4" SP)

DE250 to DE600 model range with verified 60Hz performance

Direct-drive (DE-A) & belt-drive options in carbon or stainless steel

Pressure Rating

Up to 7.4" SP (1,850 Pa)

Drive Styles

Direct DE-A / Belt Drive

Electrical (KSA)

220V / 380V 60Hz

DE Industrial Centrifugal Blower

NON-HAZARDOUS AIR STANDARD: Standard DE blowers are presented strictly for non-hazardous air and ventilation service. Flammable vapors, combustible dusts, or explosive atmospheres require a separately certified explosion-proof fan, motor, spark-resistant construction, and formal project approval.

KITCHEN GREASE & HOT GAS GATING: While the catalogue references restaurant grease exhaust and high-temperature gas emission as potential applications, these require specialized engineered configurations (such as external belt-drive motors out of the grease airstream, cleanout doors, drain plugs, and high-temperature insulation). These applications are not standard capabilities and require written configuration approval and consultant acceptance. For standard commercial kitchen grease hoods, see our Upblast Roof Fan series.

Engineering & Application Overview: DE Centrifugal Blower

The DE series comprises industrial medium-pressure centrifugal blowers manufactured by United Electrical Supplies Factory Co., engineered for ducted ventilation, process air supply, and equipment booster duty where system static resistance exceeds the capabilities of standard axial or inline fans (operating up to 7.4 in. SP / 1,850 Pa). The series includes 10 verified models from DE250 (1.5 HP, up to 1,595 CFM) to DE600 (20 HP, up to 13,765 CFM). DE-A direct-drive models connect the motor shaft directly to the forward-curved impeller, while belt-drive assemblies utilize an external shaft, bearing pedestal, and pulleys. Important: Published free-air CFM (at 0" SP) and shut-off static pressure (at 0 CFM) are opposite curve endpoints and never occur simultaneously; project sizing must use the operating point matching your system's calculated duct friction. Standard DE units are clean-air rated; commercial kitchen grease exhaust, high-temperature gases, and hazardous air service require project-specific configuration approval.

Fan Type

Industrial Centrifugal Blower

Series

DE Series (DE250 to DE600)

Drive Type

Direct Drive (DE-A) & Belt Drive Options

Airflow Range

1,595 to 13,765 CFM (2,710 to 23,387 m³/h)

Static Pressure Range

Up to 7.4 in. SP (1,850 Pa) shut-off pressure

Electrical Supply

220V/60Hz & 380V/60Hz (Model-Specific Options)

Order Nomenclature & Drive Scope

Understanding the DE model code & drive configurations

Catalogue designation DE - A - XXX FS - A - L - Q specifies exact casing, inlet diameter, impeller style, drive assembly, motor bracket, and material.

Series Designation

Industrial Centrifugal Blower Series

-A

Casing Feature

-A: Normal standard casing; -G/F/H: Filter section; -K: Heat preservation insulated; -CT: Square casing

XXX

Inlet Diameter

250, 270, 300, 350, 400, 450, 500, 550, or 600 mm spigot connection

Impeller Type

FS: Forward curved, single inlet; Backward curved or Double inlet variants available

-A

Driven Arrangement

-A: Direct drive (motor flanged to scroll); Belt drive features external shaft and bearing pedestal

-L

Motor Bracket

Mounting foot / bracket arrangement (-N, -H, -Y, -L, -B)

-Q

Housing Material

-Q: Carbon steel with black powder coating; -S: Stainless steel with natural silver finish

Direct Drive (-A)Standard DE-A Supply

DE-A Direct Drive Arrangement

The motor shaft connects directly into the impeller hub inside the scroll casing. There are no belts, pulleys, or external bearings to lubricate or align. Highly compact footprint ideal for clean air HVAC supply, equipment cooling, and booster fan rooms.

Zero belt maintenance, tensioning, or slippage losses
Compact, low-vibration continuous direct coupling
Airstream contacts motor front housing (clean air only)

Belt Drive OptionEngineered Assembly

DE Belt-Drive Arrangement

Features an independent fan shaft supported by heavy-duty pillow-block bearing pedestals, connected via V-belts and pulleys to an externally mounted motor on an adjustable base frame. The motor sits completely outside the air stream.

Motor isolated from air stream (required for hot gas/fumes)
Field-adjustable pulley ratios for custom operating duty points
Equipped with weather rain hood and OSHA belt guard

Verified 60Hz Aerodynamic Schedule

DE series centrifugal blower performance schedule

Extracted from official manufacturer 60Hz catalogue (p. 3–7). Sizing note: Free-air CFM (at 0 in. SP) and shut-off pressure (at 0 CFM) are opposite curve endpoints and never occur together; design selection must use your calculated operating duty point.

← Swipe horizontally to view all pressure ranges & electrical options →

Model	Motor Power	Speed (RPM)	Voltage (60Hz)	Free Air (0" SP)	Shut-Off SP (0 CFM)	Operating CFM Range	Operating SP Range	Max Total Press.	Drive Type
DE250	1.5 HP	1720	220V or 380V	1,595 CFM (2,710 m³/h)	2.4" SP (600 Pa)	882 – 1,560 CFM	0.1" – 2.0" SP	2.8" TP	Direct DE-A
DE270	2.0 HP	1720	220V or 380V	1,755 CFM (2,982 m³/h)	2.5" SP (625 Pa)	971 – 1,716 CFM	0.1" – 2.1" SP	3.0" TP	Direct DE-A
DE300	3.0 HP	1720	380V 3-Phase	3,176 CFM (5,396 m³/h)	3.7" SP (925 Pa)	1,035 – 3,025 CFM	0.5" – 2.6" SP	3.7" TP	Direct DE-A
DE350	3.0 HP	1120	220V or 380V	3,597 CFM (6,111 m³/h)	2.6" SP (650 Pa)	1,525 – 3,586 CFM	0.0" – 2.2" SP	2.6" TP	Direct DE-A
DE400	4.0 HP	1120	220V or 380V	4,201 CFM (7,138 m³/h)	3.1" SP (775 Pa)	1,688 – 4,095 CFM	0.3" – 3.0" SP	3.9" TP	Direct DE-A
DE400L	5.5 HP	1120	380V 3-Phase	6,714 CFM (11,407 m³/h)	3.6" SP (900 Pa)	2,201 – 6,603 CFM	0.1" – 3.3" SP	3.6" TP	Direct DE-A
DE450	7.5 HP	1120	380V 3-Phase	8,976 CFM (15,250 m³/h)	7.4" SP (1,850 Pa)	1,877 – 8,590 CFM	0.9" – 6.4" SP	9.7" TP	Direct DE-A
DE500	10 HP	1120	380V 3-Phase	9,497 CFM (16,135 m³/h)	5.6" SP (1,400 Pa)	2,470 – 9,122 CFM	0.5" – 4.4" SP	5.6" TP	Direct DE-A
DE550	15 HP	1120	380V 3-Phase	13,765 CFM (23,387 m³/h)	5.4" SP (1,350 Pa)	5,323 – 12,790 CFM	1.3" – 5.2" SP	5.4" TP	Direct DE-A
DE600	20 HP	1120	380V 3-Phase	12,671 CFM (21,528 m³/h)	4.8" SP (1,200 Pa)	3,025 – 11,479 CFM	0.9" – 4.5" SP	4.8" TP	Direct DE-A

How to Select Operating Points from Static Pressure Curves:

Total pressure (P_t) equals static pressure (P_s) plus dynamic velocity pressure (P_v). Fan selection schedules must match external static pressure losses created by connected duct runs, dampers, filters, and louvers. For custom duty points, submit your design CFM and calculated static pressure to receive a matched fan curve submittal.

Casing & Spigot Dimensions

DE series dimensional schedule

Factory certified casing dimensions, inlet spigot diameters, and rectangular outlet flange drilling patterns from catalogue drawings.

← Swipe horizontally to view all dimensions →

Model	Inlet Ø (D1 mm)	Outlet Flange (A1×B1 mm)	Height A (mm)	Width B (mm)	Depth C (mm)	Flange Holes	Mounting Base
DE250	Ø 190 mm	210 × 135 mm	524 mm	462 mm	510 mm	6-ø8×20 mm	4-ø10×20 mm
DE270	Ø 210 mm	255 × 165 mm	488 mm	453 mm	500 mm	6-ø8×20 mm	4-ø10×20 mm
DE300	Ø 200 mm	270 × 190 mm	627 mm	548 mm	574 mm	6-ø8×20 mm	4-ø10×20 mm
DE350	Ø 270 mm	295 × 195 mm	752 mm	625 mm	614 mm	6-ø8×20 mm	4-ø10×20 mm
DE400	Ø 290 mm	295 × 200 mm	865 mm	635 mm	640 mm	8-ø8×20 mm	4-ø10×20 mm
DE400L	Ø 300 mm	400 × 340 mm	777 mm	731 mm	806 mm	8-ø8×20 mm	4-ø10×20 mm
DE450	Ø 350 mm	285 × 245 mm	809 mm	761 mm	741 mm	8-ø8×20 mm	4-ø12×30 mm
DE500	Ø 360 mm	394 × 380 mm	900 mm	800 mm	877 mm	8-ø8×20 mm	4-ø12×30 mm
DE550	Ø 450 mm	476 × 355 mm	1023 mm	943 mm	947 mm	8-ø8×20 mm	4-ø12×30 mm
DE600	Ø 500 mm	476 × 355 mm	1023 mm	943 mm	947 mm	8-ø8×20 mm	4-ø12×30 mm

Key Features

Engineered construction & design advantages

Heavy-duty fabrication designed for reliable commercial and industrial air movement in high-ambient Middle Eastern conditions.

Continuous full-seam welded carbon steel or stainless steel scroll casing

Corrosion-resistant electrostatically applied and high-temperature baked powder coating

Direct-drive (DE-A) and belt-drive arrangements with modular motor mounting frames

Multi-angle discharge capability configurable in 0°, 90°, 180°, or 270° orientation

Tested dynamic balancing across three planes prior to factory packaging

High static pressure capability overcoming long duct runs, elbows, and filtration resistance

Model-matched 60Hz motors rated for 220V single/three-phase or 380V three-phase operation

Optional accessories including companion flanges, flexible connectors, vibration springs, and rain hoods

Specifications

Technical specifications

Reference engineering summary for MEP consultants, contractors, and procurement engineers.

Specification Parameter	DE Series Capability & Options
Product Category	Centrifugal Blower / Medium Pressure Blower
Series Designation	DE Series (United Electrical Supplies Factory Co.)
Available Sizes	DE250, DE270, DE300, DE350, DE400, DE400L, DE450, DE500, DE550, DE600
Airflow Capacity Range	1,595 to 13,765 CFM (2,710 to 23,387 m³/h) free air
Static Pressure Range	Shut-off pressures from 2.4" to 7.4" SP (600 to 1,850 Pa)
Drive Arrangements	DE-A Direct Drive (motor directly mounted) or Belt Drive (shaft & bearing pedestal)
Housing Materials	Carbon Steel (-Q, black powder-coated) or Stainless Steel (-S, silver finish)
Electrical Supply (60Hz)	220V/60Hz (DE250-DE400) or 380V/60Hz 3-Phase (DE250-DE600)
Motor Power Range	1.5 HP to 20 HP (1.1 kW to 15 kW)
Discharge Angles	Field-rotatable or factory-ordered in 0°, 90°, 180°, or 270° discharge positions
Inlet / Outlet Design	Round circular bell-mouth inlet with rectangular drilled discharge flange
Application Scope	Non-hazardous clean air and ventilation baseline; grease & hot gas require engineering review

Application Scope

Industrial centrifugal blower applications

Where medium-pressure ducted airflow is required to overcome duct resistance, equipment loads, and air transfer requirements.

Ducted industrial ventilation

Process heat, fumes, and air through long ductwork runs with high static resistance

Equipment booster cooling

High airflow and pressure support for machinery, electrical panels, and transformer rooms

Commercial supply & transfer

Overcomes heavy duct friction losses, elbows, and sound attenuators in commercial buildings

Dust & particle extraction (Clean air)

Light non-combustible airborne particles when connected through secondary cyclone/bag filters

Mechanical room exhaust

Stale heat and ambient emissions from equipment rooms requiring dedicated duct runs

Kitchen grease exhaust (Review required)

Requires documented belt-drive motor out of airstream, access doors, and consultant approval

High-temperature gas (Review required)

Hot process emissions requiring verified temperature limits, cooling discs, and motor insulation

MEP project engineered supply

Selected against exact system resistance curves with certified submittals and Saudi compliance

Engineering Selection

Project selection checklist & sizing parameters

To ensure accurate fan curve intersection and motor sizing, provide the following parameters for technical quotation.

Required operating airflow in CFM or m³/h (must be design airflow, not free-air 0" SP)

Calculated external static pressure in inches water gauge (in. w.g.) or Pascals (Pa)

Air composition: confirm clean air, non-corrosive, non-combustible, and ambient temperature

Drive preference: compact direct-drive (DE-A) vs. belt-drive with external motor frame

Electrical power supply: 220V/60Hz (available on DE250-DE400) or 380V/60Hz 3-Phase

Casing material: heavy-gauge carbon steel (-Q, black) or stainless steel (-S, silver)

Discharge orientation angle (0°, 90°, 180°, or 270°) and rotation direction

Project city, installation environment (indoor plant room vs. outdoor rooftop), and quantity

Accessories

Compatible installation & control accessories

Factory supplied options to facilitate duct connection, sound/vibration isolation, and outdoor weather protection.

Companion Inlet & Outlet Steel Flanges

Flexible Anti-Vibration Duct Connectors (Canvas / Neoprene)

Spring Vibration Isolators & Neoprene Mounting Pads

Weatherproof Outdoor Motor Rain Hood & Belt Guard

Inlet Filter Box with Washable Metal Mesh or Pleated Media

Scroll Housing Cleanout Inspection Door & Casing Drain Plug

Motor Slide Rails & Heavy-Duty Structural Base Frame

NEMA / IP55 Weatherproof Lockable Disconnect Switch

Technical Resources

Documentation, catalogues & submittals

Official catalogue with complete 60Hz performance curves, dimensional drawings, and procurement documentation.