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Inline Fully Mixed-flow Fan w/ Sound Vault-YFIMF-ST

● Wheel Specification: 400~1,250
● Installation: hanging, floor-mounted
● Volume range: 900~800,00 m³/h
● Static pressure range: 0~1,027 Pa
● Patented fully mixed flow wheel design, high-efficiency and low noise.
● Full-process control over flow passage to improve aerodynamic efficiency. Balance quality grade up to G2.5 ( AMCA 204 ).
● Direct drive, high efficient and maintenance-free.
● Sealed cabinet design to reduce the noise.
● Aluminum alloy frame, Light weight and good appearance.

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Fully mixed flow: completely surpass the time of semi mixed flow
-- Revolutionary breakthrough: impellers with front disc, achieving real fully mixed flow.
-- Full-process control over flow passage to improve aerodynamic characteristics.
-- Optimized design of CFD flow field simulation.
-- Inlet Venturi tube: streamlined design.
-- Dome-shaped hub: greatly reduce turbulent flow and backflow.
-- Continuously optimized patent 3D curved blade design.

Effect of fully mixed flow:
-- Greatly improve the efficiency (by 28% on average).
-- Wide performance range of high efficiency.
-- Optimal for medium-pressure inline fans.

Advanced process
-- Inlet Venturi tube: spinning process to ensure streamline aerodynamic characteristics.
-- Inlet Venturi tube: completely substitute cone, ensuring smooth air flow.
-- Front disc: spinning process to ensure streamline aerodynamic characteristics.
-- Blade: dedicated fixture to ensure precise welding positioning of 3D curved surfaces.
-- Hub: dome shaped, with obvious cowling effect.
-- Balance quality grade up to G2.5.

Outlet straightening vanes
-- Get the swirl flow behind the blade to be smoother.
-- Guide the air flow to move axially, reducing turbulent flow;
-- Convert partial dynamic pressure to static pressure;
-- Improved aerodynamic performance and efficiency of static pressure;
-- Effectively reduce the noise.

Difference from semi mixed flow impeller
-- Front disc: none for semi mixed flow impeller.
-- Inlet Venturi tube: none for semi mixed flow impeller, substituted by a cone.
-- Blade: plate type blade for semi mixed flow impeller.
-- Hub : cone-like design for semi mixed flow impeller, with turbulent flow.
-- Straightening vanes within the cylinder: none for semi mixed flow impeller.


Performance features
-- Compared with inline centrifugal fan: higher efficiency.
-- Compared with inline axial fan: higher pressure.
-- Between Point A and Point B, high efficiency and low noise.
-- Between Point A and Point B, optimal for inline fans.

Complete functions
-- Smoke removal duty, positive pressure air supply, fire certification.
-- Explosion-proof supply & exhaust.
-- Two-speed ventilation.
-- Variable velocity variable frequency.
-- Laboratory.
-- Outdoor roof installation with cowl.

Advantages of belt drive: precise, adjustable
-- Air volume is adjustable on site.
-- More precise selection up to the requirements of design conditions.
-- Easier maintenance and replacement of motor.
-- Independent bearing to bear the vibration, extending the bearing life.
-- On-site rotation, with the motor at a different position.
-- Base with adjustable belt.
-- Flexible on-site design change.

Advantages of direct drive: efficient, maintenance-free
-- Higher transmission efficiency.
-- No wearing parts, low maintenance.
-- Easier and more effective servicing and maintenance.
-- Sealed self-lubricating bearing for motor, increasing service life.
-- Compact design to save installation space.

Convenient and flexible installation
-- Horizontal installation on a base [belt drive type, with the motor at one side].
-- Horizontal suspension [belt drive type, with the motor at one side].
-- Vertical installation on a base.
-- Vertical suspension.
-- Roof installation.

Sound vault housing: running more quiet and stable
-- To block the fan noise effectively.
-- To reduce medium-high frequency sound substantially.
-- High rigidity frame structure for running more stable.
-- Especially suitable for sound critical applications.
-- Concise & atmospheric to enhance taste.

Center Frequencies(Hz)









 Attenuation Value(dB)









Attenuation Value(dB)









*Note: Value with optional acoustical lining.

Patent and certification
-- National patent products.
-- AMCA certification for aerodynamic characteristics and noise.
-- FEG is licensed by AMCA.
-- Products with AMCA certification mark.


Naming Convention:

Tech Spec

YFIMF-ST Technical Specification

Fan Type
The fan shall be fully mixed-flow fan equipped with fully mixed-flow wheel, The drive type shall be direct drive and belt drive. The mixed-flowed impellers shall be made of steel and must have front discs and dome-shaped hubs, and blades with 3D curved surface shall be adopted. Besides, after equilibrium calibration, the impellers shall conform to the Balance Quality Grade G2.5 as per AMCA 204 standard.

Quality Standards
The fan shall be tested in accordance with AMCA Standard 210 and 300 and AMCA licensed according to AMCA Publication 211 and 311 for sound, air performance and FEG. And each fan shall be affixed with AMCA sound, air performance and FEG. Seal, The manufacturer must own the production license for industrial products and ISO9001 quality system authentication.

Fan Structure
The fan shall be equipped with streamlined inlet Venturi tube, with straightening vanes mounted within the cylinder to reduce turbulent flow and improve efficiency.
Fan cynlinder: double-layer structure shall be adopted for the fan cylinder, i.e., straightening inner cylinder and straightening vanes shall be configured, and the straightening inner cylinder shall be connected with the inner wall of the outer cylinder thorugh the straightening blade, which can both secure the straightening cylinder and improve the aerodynamic performance of the fan and the efficiency of static pressure; smoother air flow is required; and the blades of the straightening vanes shall be of 3D curved surface in compliance with flow field characteristics.
Access door: The fan shall be equipped with screw-type access door at the blade side for cleaning the impeller.

Fan Materials

The cylinder and impeller of the fan shall be continuously welded and made of quality carbon steel no less than 2mm thick to ensure the long-term safe and reliable use of the fan.


Fan surface shall be polished and cleaned up to remove particulates, welding slag, burrs, sharp edge, iron, oil, then epoxy coating [options: colour changes are available], fan surface shall be free of sags, wrinkle, blisters, exposed metal or peeling after coating. It shall be no corrosion and rust at least 10 years in allowable working condition.

Driving Type

Direct drive type: The wheel shall be directly connected with the motor. The motor shall adopt B5 installation structure, and its protection grade shall be IP54, while insulation class F and temperature rise B. The motor bearing shall be self-lubricating ball bearing. The motor shall be within the straightening cylinder and isolated from the air flow to prevent the effect of the conveying medium on the motor performance; the power reserve coefficient of the motor shall be per 110% so as to improve the safety in using the motor.
Junction box of motor: Since the motor is within the fan, the supplier shall provide junction boxes to lead the wire out of the fan, and correct types of junction boxes shall be selected according to the specific applications, such as fire protection type, explosion proof type and common type.
Belt drive type: The fan shaft shall be made of 40Cr and hot-treated with homogeneous furnace to ensure that the hardness grade reaches HB286 and the yield limit reaches 550MPa, and anti-corrosion hardening treatment shall be conducted on the surface, and whole dynamic balancing shall be conducted on such surface together with the impeller. The designed operation speed shall at least exceed 25% of the maximum operation speed of the fan.
Belt pulley: the belt pulley shall have specifications as per 150% of the drive power, be made of cast iron, and be fixed with taper lock bush to facilitate dismantlement.
Belt: the belt shall be resistant from oil, heat and electrostatic discharge.
Bearing: independent metal bearing shall be used for supporting the fan shaft to prevent vibration from directly applying onto the motor. The bearing shall be sealed-for-life, self-lubricating ball bearing of pillow block type and metal material. At the maximum rotation speed as indicated in the catalogue, the bearing life shall be no less than (L-10) 80000 hours. And international famous brands shall be selected, such as FYH, and SKF, etc.
Extension lubricating oil tube for bearing: the extended lubricating oil tube is used outside the machine for conveniently filling grease to the bearing without dismantling the fan. And the material of the oil tube shall be copper.
Support: the driving device shall be supported with powder-coated anti-corrosion steel plate, the belt shall be adjustable, and the design of the motor base shall ensure the parallelism of the fan shaft and the motor shaft.
Belt guard: semi-sealed belt guard shall be set to avoid personal injuries.
Motor: The motor shall match with the fan load, and B3 installation structure shall be adopted. The protection grade of the motor shall be IP54, while insulation class F and temperature rise B. The motor bearing shall be self-lubricating ball bearing. The power reserve coefficient of the motor shall be per 110% so as to improve the safety in using the motor; and TEFC, 2-SPD, EXP, VFD, 60Hz and other correct motor types must be selected according to the specific working conditions. And epoxy spray rain cover shall be provided for motors to be installed outdoors.


Extension support: extension support accessories shall be provided for the users to select and meeting the requirements of field installation;
Other accessories: relevant accessories shall be provided according to the specific requirements for each set of equipment, such as air volume control damper, gravity-held air back draft damper , fireproof regulating damper, fire damper, vibration isolators, protection net for inlet and outlet, and flexible joints for inlet and outlet, etc.

Explosion-proof Structure (Only for explosion-proof type)

Fan shall conform to Spark C explosion-proof structure according to AMCA99 Standard. The inlet shall mount copper ring and the motor shall adopt explosion-proof type. The whole fan should own CNEX certification and the manufacturer must own the production license for anti-explosion electric products.

Fire fighting Certification (Only for smoke removal duty)
The fan shall be tested OK in complying with the General Usage Axial Fan technical Specification (China National Standard JB/T 10562-2006). A test report issued by licensed authorities shall be provided. The fan must be tested according to China National Standard GA 211-2009, Fire Fighting Smoke Removal Fan High Temperature Testing Method, running continuously over 30 minutes when the main duct air temperature is 280 degrees centigrade. The high temperature resistance character must be qualified by presenting an official certificate.


Permanently fixed aluminum nameplate shall be fixed on fan body clearly display fan mark, product model and serial number (i.e.: unique ID for each fan), so that the customer can use this number to find out the parts used.

Acceptable Manufacturers
Qualified suppliers shall have an AAA credit rating. Providing INFINAIR or similar products, with their design based on YFIMF models of INFINAIR.


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