Twin City Fan & Blower

Overview

Twin City Fan & Blower's Model DSI direct drive and Model BSI belt driven square inline fans are specifically designed for duct applications handling relatively clean air, including supply, exhaust, and return air systems. These fans offer high efficiency and quiet operation in a compact design that can be mounted in any position (horizontal, vertical, or angular). Duct collars are provided for easy mounting without the need for square-to-round duct transitions. The units can be easily serviced through side access panels without removing duct connections.

Square inline centrifugal units feature high-efficiency, non-overloading, backward-inclined centrifugal wheels precisely matched to a spun venturi. All wheels are statically and dynamically balanced. Units are manufactured under strict quality assurance standards to ensure cataloged performance and years of maintenance-free operation. Square inline fans are not intended for outdoor applications.

Model DSI

Available in 10 sizes from 080 through 165. Airflow up to 5,800 CFM. Static pressure up to 2" w.g.

Model BSI

Available in 29 sizes from 080 through 402. Airflow up to 27,400 CFM. Static pressure up to 3.5" w.g.

Typical Applications Include:

• General HVAC (exhaust, filtration, return and supply, air of commercial buildings)
• Air Pollution Control
• Airport Exhaust
• Automotive
• Fertilizer
• Food & Beverage
• Laboratory Exhaust
• Metal & Mineral Processing
• Office Exhaust
• Restroom Exhaust
• Warehouse Exhaust
• Water Treatment

Wheel Types

Backward Inclined

Optional Construction

• Spark Resistant Construction (Type A, B, and C)
• Easy Access Construction

Certifications

• AMCA Sound/Air and FEG
• UL 705 Listed for Electrical
• OSHPD Seismic Preapproval per OSP-0271-10

Note: UL/cUL 705 listed for electrical applications (File No. E158680).

Note: AMCA Seal for sound and air performance, and fan efficiency grade (FEG) are based on tests performed in accordance with AMCA Publication 211 and AMCA Publication 311.

Construction Features

• Housings: Heavy-gauge galvanized steel construction.
• Removable Side Panels: Provide easy access for service and maintenance without removing duct connections. Power assembly can be removed through side panels. Side panels can allow for 90-degree side discharge (requires optional accessory).
• Duct Collars: Facilitate direct ductwork attachment, eliminating the need for square-to-round transitions.
• Belt Tube/Bearing Cover (Model BSI): Heavy-gauge galvanized steel enclosing belts, fan sheave, and bearings within the airstream.
• Drive Frame (Model BSI): Heavy-gauge galvanized steel with a pivoting motor base for simple belt tensioning.
• Wheel: Backward-inclined, non-overloading, all-aluminum wheel and hub, statically and dynamically balanced for long life and quiet operation.
• Mounting Brackets: Galvanized steel brackets for horizontal or vertical mounting.
• Pulleys (Model BSI): Heavy-duty cast iron, adjustable pulleys for speed variation.
• Shaft (Model BSI): Precision ground and polished with a first critical speed of at least 125% of the fan's maximum operating speed.
• Bearings (Model BSI): Prelubricated cast iron pillow block bearings with zerk fittings, designed for an average L-50 life of 500,000 hours or more at maximum cataloged operating speeds.
• Disconnect Switch: Mounted and prewired NEMA 1 disconnect switch provided as standard for safe servicing.

Disconnect Switches

Disconnect switches provide positive electrical shutoff during fan cleaning or maintenance.

• NEMA 1 Disconnect Switch (Standard): Available shipped loose for field mounting/wiring or factory mounted/wired. Suitable for ODP or TEFC motors.
• NEMA 3R Disconnect Switch: Rain-proof, available shipped loose or factory mounted/wired externally.
• NEMA 4 Disconnect Switch: Water and dust-tight, available shipped loose or factory mounted/wired externally.
• NEMA 7/9 Disconnect Switch: Recommended for fans with explosion-proof motors, designed for hazardous environments. Available shipped loose.

Options/Accessories

Various accessories are available to enhance fan functionality and performance:

• Belt Guard (Model BSI): Formed galvanized steel guard for drive assembly, offered in lieu of motor cover.
• Motor Cover (Model BSI): Formed galvanized steel cover for motor and drives, serves as OSHA belt guard.
• Extended Lube Lines (Model BSI): Exterior mounting zerk fittings for fan shaft bearings for relubrication from outside the unit.
• Vibration Isolators: Spring or neoprene type for ceiling suspended or floor mounted installations.
• NEMA 3R Safety Disconnect Switch: Provides positive electrical shutoff and personnel protection.
• Backdraft Dampers: Automatic or motorized operation with felt-edged blades for quiet operation. Frames are galvanized steel, blades are 26-gauge aluminum. Ship loose for field mounting. Motorized dampers recommended for low CFM applications. Available with various voltage services (115, 208, 230, 460, 575, 24V). End switches available.
• Variable Speed Control (DSI Models): Optional accessory for airflow adjustment and system balancing. Solid-state (Tri-ac) design, starts motor on high speed for better startup. Can be shipped separately, factory installed, or field installed. Motor must be ODP 115V, PSC, or shaded pole type.
• Filter Box: Contains two-inch aluminum wire mesh, removable/washable filters. Constructed of galvanized steel with duct collars for easy mounting and removable side panels for filter cleaning/replacement. Disposable paper filters also available (1-inch filters available).
• Outlet Guard: Inlet and outlet guards available for all models, mount inside the unit without interfering with ductwork.
• Other Accessories Include: Special Coatings, Insulated Housings, Aluminum Construction, Stainless Steel Hardware, NEMA 4 & 7/9 Disconnect Switches.

Electronically Commutated (EC) Motors

Twin City Fan & Blower offers custom-engineered Electronically Commutated (EC) motors, utilizing the latest motor technology (also known as Brush Free or Brushless DC). EC motors use an electronic circuit board to control motor functionality, operating off single-phase AC power converted to DC power internally. They offer high efficiency, even at part load, with an expanded speed control range and various speed control options. Available for 115V, 208-230V, or 277V single-phase electrical power.

Benefits of EC Motors:

• Efficiencies up to 85%.
• Constant efficiency across varying motor speeds.
• Up to 66% energy savings compared to traditional PSC motors.
• Performance comparable to belt-drive fans with direct-drive maintenance benefits.
• 80% usable turndown range (compared to 40% maximum on PSC motors).
• Soft start for smooth, quiet fan startup.
• Lower operating temperatures for longer life and reduced energy consumption.
• Permanently lubricated heavy-duty ball bearings.
• Elimination of VFDs reduces initial cost.

EC Motor Options:

• 1/6HP to 1HP: Available in 115V (single phase) for 1/6HP, and 115V, 208-230V, 277V (single phase) for 1/4HP to 1HP. Available in ODP or TENV enclosures. Standard features include motor-mounted speed control dial and 0-10VDC control leads. Remote mounted speed control dial is also available.
• 1HP & 2HP: Available in 1HP (115V, 208-230V, single phase) and 2HP (208-230V, single phase). Features TEFC (totally enclosed fan cooled) enclosure. Available with motor-mounted speed dial or 0-10VDC control lead.

Side Discharge Options

Side discharge kits (panels, mounting collars, hardware) provide 1-way, 2-way, or 3-way discharges, offering adaptability and avoiding system effects from disrupted airflow during 90-degree duct turns.

Configurations:

• Standard: Rear discharge.
• 1-Way: Rear, Left, or Right discharge.
• 2-Way: Left and Rear, or Right and Rear discharge.
• 3-Way: Left, Right, and Rear discharge.

Note: Performance may vary based on discharge position. Correction factors are provided but not AMCA certified. Always check BHP when selecting motor HP and fan size.

Duct Openings:

Tables detail duct collar dimensions and required duct sizes for various models and discharge configurations (Left/Right Discharge, Rear Discharge/Inlet).

Performance Data

Detailed performance data tables are provided for both DSI and BSI models. These tables list performance ratings based on fan size, motor horsepower (HP), RPM, and various static pressures (from 0.125" to 3.5" w.g.). Data includes CFM (Cubic Feet per Minute), SONE (sound performance), and BHP (Brake Horsepower). Performance is certified for Installation Type B (Free inlet, ducted outlet) and tested in accordance with AMCA standards. Fan Efficiency Grades (FEG) are also indicated.

Note: Performance ratings do not include the effects of appurtenances (accessories). Sound ratings are loudness values in fan sones at 1.5m (5 ft.) in a hemispherical free field calculated per AMCA International Standard 301.

Dimensional Data

Dimensional data is provided for both DSI (Direct Drive) and BSI (Belt Driven) models. Tables list dimensions (A through J) for each model size, along with average ship weight and side discharge size. Filter box assembly dimensions and quantities are also detailed.

Typical Specifications

Model DSI: Direct drive centrifugal square inline fans manufactured by Twin City Fan, Minneapolis, MN. Performance ratings conform to AMCA Standards 205, 211, and 311. Fans are tested in an AMCA accredited laboratory and licensed to bear the AMCA certified ratings seal. Units are UL 705 listed. Construction features heavy-gauge galvanized steel, removable side panels for access, universal mounting brackets, and a permanently attached nameplate. Wheels are backward-inclined, aluminum, statically and dynamically balanced. Motors are heavy-duty ball bearing type with factory-installed disconnect switch. UL recognized motors. Various accessories are available. Factory run tests ensure performance. Guarantee covers workmanship and materials for at least one year from startup or 18 months from ship date.

Model BSI: Belt driven centrifugal square inline fans manufactured by Twin City Fan, Minneapolis, MN. Performance ratings conform to AMCA Standards 205, 211, and 311. Fans are tested in an AMCA accredited laboratory and licensed to bear the AMCA certified ratings seal. Units are UL 705 listed. Construction features heavy-gauge galvanized steel, removable side panels, universal mounting brackets, and a permanently attached nameplate. Wheels are backward-inclined, aluminum, statically and dynamically balanced. Shafts are precision ground. Bearings are one-piece pillow block type with relubricable zerk fittings, designed for long life. Drives are sized for minimum 150% of driven horsepower. Motors are heavy-duty ball bearing type with factory-installed disconnect switch. UL recognized motors. Various accessories are available. Factory run tests ensure performance. Guarantee covers workmanship and materials for at least one year from startup or 18 months from ship date.