Dashun HTF smoke-exhaust fans · variant and two-mode selection

Separate impeller, speed and installation suffixes

The catalogue’s normal-pressure group I/II uses an axial impeller; its medium-pressure III/IV group uses mixed flow. The Roman numerals also distinguish single and two-speed motors within those groups. They are not four interchangeable names for the same impeller and duty.

D has its own low-pressure table. W refers to roof installation with a selected cap, and the roof sheet states that corresponding I–IV/D forms can be supplied in that arrangement. X1/X2 have distinct silencing constructions. Ask for the complete configuration and approved selection, including the catalogue’s naming of GYF as a comparable product family; do not silently relabel a GYF quotation as the exact certified HTF designation.

Read the recommended points as pairs on one schedule

The HTF-I No.3.5 table gives five recommended points. Its 6,122 m³/h at 205 Pa and 3,500 m³/h at 552 Pa values describe different points at 2,900 r/min. They do not support 6,122 m³/h at 552 Pa. The column is total pressure, unlike a static-pressure catalogue.

The HTF-II No.5 table separately lists 2,900 and 1,450 r/min schedules. Its first high/low rows are 9,824 m³/h at 510 Pa and 4,912 m³/h at 127 Pa. These examples illustrate how to read the table; they are not a selection for the buyer’s duct network. Require a marked curve with actual air conditions, resistance and motor loading for each mode. The catalogue uses “standard conditions” without a complete reproduced density definition; confirm that basis and any correction with the supplier.

Assess the thermal claim and certificate at model level

The original explanation says operation for more than 60 minutes at 300°C and separately 20 hours per run at 100°C. It cites an older 1999 test-standard reference and national inspection wording. These are supplier catalogue assertions, not a complete temperature/duration report for every variant and accessory configuration.

The actual original certificate identifies an axial smoke-exhaust product, HTF-I-16A as the unit/main type, with HTF-I-16B, 16C, 16D and 16E included. It cites XF 211-2009 and a 2019 certification rule, with printed dates 2024-11-08 to 2029-11-07. The official issuer-site attempt failed to produce a readable status result. Ask for a verifiable current record and full report, including the offered size/speed, motor and applicable extensions, before relying on it for an order. A named size-16 certificate does not by itself certify No.3.5 or a mixed-flow IV fan.

Resolve flange drilling and roof space before fabrication

The I/II, III/IV and D sheets use different dimension tables. For the I/II No.3.5 example, L is 520 mm and D1/D2/D3 are 360/390/430 mm. Use the referenced sketch rather than treat all three diameters as one duct size. The note says flange drilling dimensions are reference-only and the manufacturer normally does not drill them; agree the mating flange and drilling before delivery.

The W roof sheet gives base, fan and cap dimensions and offers FRP or steel cap forms. Confirm the cap material, complete height, roof curb/support, weather detail and removal clearance with an approved drawing. A roof illustration is not a wind-load, weathering or building-interface approval. The normal I/II straight fan envelope should not be used as the complete roof assembly.

Silencing claims need a frequency and pressure basis

The X description distinguishes X1, with inlet/outlet silencers, from X2, with a silenced casing and inlet/outlet silencers. It quotes broad attenuation ranges for different silencer lengths, but gives no full octave-band selection or agreed installed measurement condition. Obtain frequency-dependent acoustic data and the actual added resistance before selecting the fan and attenuator together.

The performance tables list A-weighted levels without a full reproduced measurement method/distance. Do not turn them into an indoor boundary guarantee or subtract a broad attenuation range to promise a final room noise. Include duct-borne sound, casing breakout, vibration and the project receptor in the acoustic assessment. Corrosive, grease-laden or explosive service likewise needs an explicit material/protection selection; the general application list is not an approval for those media.

Agree changeover and commissioning with the selected motor

The final original sheet includes two-speed wiring diagrams and instructions to read the product manual, check current/three-phase supply, inspect abnormal operation and coordinate smoke outlet/fan interlocking. These catalogue diagrams should inform questions, not replace the current selected motor terminal diagram or the responsible electrical designer’s controls.

1. Approve both duty modes

   Record the full variant/number, normal and emergency airflow/total pressure, speed/motor data, media and required thermal duty.

2. Approve installation and controls

   Confirm flange drilling, supports/access, roof or silencer package, motor-specific wiring and the project’s smoke-control interlocks/changeover.

3. Witness and document

   Check direction, speeds, airflow/pressure, current, vibration and interlock response at defined conditions; retain reports, settings and maintenance instructions.