RAFAVENT

Double-Inlet Forward-Curved Centrifugal Fans

Published product and engineering information

RAFAVENT CENTRIFUGAL FAN SUBFAMILY

Double-Inlet Forward-Curved Centrifugal Fans

Double-inlet, double-width forward-curved centrifugal fans for high-volume low-to-medium-pressure ventilation duties.

DIDW · DOUBLE INLET · DOUBLE WIDTHPreliminary engineering data

CONSTRUCTION AND APPLICATION

Forward-curved double-inlet arrangement

Air path

Balanced air entry from both sides into one double-width multi-blade forward-curved wheel.

Drive arrangement

External shaft and bearings; belt-drive selection requires separate fan and motor speeds, pulley pitch diameters and transmission review.

Typical applications

AHUs, cabinet ventilation, clean-air supply and extract systems requiring higher volume at low-to-medium pressure.

Required production controls

Wheel balancing, shaft and bearing verification, belt-load review, vibration acceptance and confirmed discharge orientation.

RAFAVENT Engineering Development Scenario — Preliminary and Non-Certified. The following values are calculated scenarios, not laboratory-certified RAFAVENT product ratings. Final selection requires confirmed geometry, duty point, motor loading, production drawing and test validation.

Calculated scenario summary

Study ID	Wheel Ø mm	Fan rpm	Sample Q m³/h	Pt Pa	Ps Pa	Max assumed shaft kW	Motor budget kW
SC-FWD-DI-310	310	1129.0	8,611–11,301	474–522	234–383	3.31	5.5
SC-FWD-DI-350	350	1000.0	10,976–14,406	474–522	234–383	4.22	5.5
SC-FWD-DI-400	400	875.0	14,336–18,816	474–522	234–383	5.51	7.5
SC-FWD-DI-450	450	777.8	18,144–23,814	474–522	234–383	6.97	11
SC-FWD-DI-500	500	700.0	22,400–29,400	474–522	234–383	8.61	11
SC-FWD-DI-560	560	625.0	28,099–36,879	474–522	234–383	10.80	15
SC-FWD-DI-630	630	555.6	35,562–46,675	474–522	234–383	13.66	18.5
SC-FWD-DI-710	710	493.0	45,167–59,282	474–522	234–383	17.35	22

Study IDs are engineering scenarios, not released sales model codes. Similar pressure ranges result from the constant tip-speed assumption and do not represent eight independent tests.

Six-point calculated data

SC-FWD-DI-310 — six-point calculated Q–pressure–power data

Point	Q m³/h	Pt Pa	Ps Pa	Assumed shaft kW
1	8,611	522	383	2.77
2	9,149	517	360	2.92
3	9,687	509	333	3.05
4	10,225	500	304	3.16
5	10,763	489	272	3.25
6	11,301	474	234	3.31

Pt (Pa)600.30861111301Q (m³/h)Ps (Pa)440.40861111301Q (m³/h)P shaft (kW), assumed η=45%3.80861111301Q (m³/h)

Sampled interval only; no extrapolation. Assumed efficiency 45%. Motor budget covers these six study points only, is not a purchase specification, and is not guaranteed conservative.

SC-FWD-DI-350 — six-point calculated Q–pressure–power data

Point	Q m³/h	Pt Pa	Ps Pa	Assumed shaft kW
1	10,976	522	383	3.54
2	11,662	517	360	3.72
3	12,348	509	333	3.88
4	13,034	500	304	4.03
5	13,720	489	272	4.14
6	14,406	474	234	4.22

Pt (Pa)600.301097614406Q (m³/h)Ps (Pa)440.401097614406Q (m³/h)P shaft (kW), assumed η=45%4.901097614406Q (m³/h)

Sampled interval only; no extrapolation. Assumed efficiency 45%. Motor budget covers these six study points only, is not a purchase specification, and is not guaranteed conservative.

SC-FWD-DI-400 — six-point calculated Q–pressure–power data

Point	Q m³/h	Pt Pa	Ps Pa	Assumed shaft kW
1	14,336	522	383	4.62
2	15,232	517	360	4.86
3	16,128	509	333	5.07
4	17,024	500	304	5.26
5	17,920	489	272	5.41
6	18,816	474	234	5.51

Pt (Pa)600.301433618816Q (m³/h)Ps (Pa)440.401433618816Q (m³/h)P shaft (kW), assumed η=45%6.301433618816Q (m³/h)

Sampled interval only; no extrapolation. Assumed efficiency 45%. Motor budget covers these six study points only, is not a purchase specification, and is not guaranteed conservative.

SC-FWD-DI-450 — six-point calculated Q–pressure–power data

Point	Q m³/h	Pt Pa	Ps Pa	Assumed shaft kW
1	18,144	522	383	5.84
2	19,278	517	360	6.15
3	20,412	509	333	6.42
4	21,546	500	304	6.66
5	22,680	489	272	6.85
6	23,814	474	234	6.97

Pt (Pa)600.301814423814Q (m³/h)Ps (Pa)440.401814423814Q (m³/h)P shaft (kW), assumed η=45%8.001814423814Q (m³/h)

Sampled interval only; no extrapolation. Assumed efficiency 45%. Motor budget covers these six study points only, is not a purchase specification, and is not guaranteed conservative.

SC-FWD-DI-500 — six-point calculated Q–pressure–power data

Point	Q m³/h	Pt Pa	Ps Pa	Assumed shaft kW
1	22,400	522	383	7.22
2	23,800	517	360	7.60
3	25,200	509	333	7.92
4	26,600	500	304	8.22
5	28,000	489	272	8.45
6	29,400	474	234	8.61

Pt (Pa)600.302240029400Q (m³/h)Ps (Pa)440.402240029400Q (m³/h)P shaft (kW), assumed η=45%9.902240029400Q (m³/h)

Sampled interval only; no extrapolation. Assumed efficiency 45%. Motor budget covers these six study points only, is not a purchase specification, and is not guaranteed conservative.

SC-FWD-DI-560 — six-point calculated Q–pressure–power data

Point	Q m³/h	Pt Pa	Ps Pa	Assumed shaft kW
1	28,099	522	383	9.05
2	29,855	517	360	9.53
3	31,611	509	333	9.94
4	33,367	500	304	10.31
5	35,123	489	272	10.60
6	36,879	474	234	10.80

Pt (Pa)600.302809936879Q (m³/h)Ps (Pa)440.402809936879Q (m³/h)P shaft (kW), assumed η=45%12.402809936879Q (m³/h)

Sampled interval only; no extrapolation. Assumed efficiency 45%. Motor budget covers these six study points only, is not a purchase specification, and is not guaranteed conservative.

SC-FWD-DI-630 — six-point calculated Q–pressure–power data

Point	Q m³/h	Pt Pa	Ps Pa	Assumed shaft kW
1	35,562	522	383	11.46
2	37,785	517	360	12.06
3	40,008	509	333	12.58
4	42,230	500	304	13.04
5	44,453	489	272	13.42
6	46,675	474	234	13.66

Pt (Pa)600.303556246675Q (m³/h)Ps (Pa)440.403556246675Q (m³/h)P shaft (kW), assumed η=45%15.703556246675Q (m³/h)

Sampled interval only; no extrapolation. Assumed efficiency 45%. Motor budget covers these six study points only, is not a purchase specification, and is not guaranteed conservative.

SC-FWD-DI-710 — six-point calculated Q–pressure–power data

Point	Q m³/h	Pt Pa	Ps Pa	Assumed shaft kW
1	45,167	522	383	14.55
2	47,990	517	360	15.32
3	50,813	509	333	15.98
4	53,636	500	304	16.57
5	56,459	489	272	17.05
6	59,282	474	234	17.35

Pt (Pa)600.304516759282Q (m³/h)Ps (Pa)440.404516759282Q (m³/h)P shaft (kW), assumed η=45%20.004516759282Q (m³/h)

Sampled interval only; no extrapolation. Assumed efficiency 45%. Motor budget covers these six study points only, is not a purchase specification, and is not guaranteed conservative.

Calculation basis and limitations

Reference basis: Kruger FDA 500 curve readings at 900 rpm; reference manufacturer remains identified and is not presented as RAFAVENT test data.
Density 1.20 kg/m³; geometrically similar scaling; constant diameter × speed; assumed total efficiency 45%, transmission efficiency 95% and 15% motor margin.
Static pressure equals total pressure minus calculated outlet velocity pressure using an assumed scaled discharge area.
Motor output is not shaft power. Final absorbed-power review across the operating range is mandatory.
No LpA at 3 m is stated because available reference sound data must not be converted into a RAFAVENT product claim without defined installation and test conditions.
Double-inlet is not the same as a twin-fan assembly.

Technical documents, dimensions and service

Technical documents and dimensions

Final dimensions, connection details, materials, motor data and project drawings are issued for the selected configuration after engineering review.

Installation and maintenance

Provide level support, flexible connections, guarded drive components, alignment checks and safe maintenance access. Follow the approved project-specific O&M document.

Selection tables and calculated curves on this page are preliminary engineering guidance, not certified RAFAVENT test ratings. Confirm the operating point and controlled documents before order.

Information required before selection

Required airflow and static pressure
Operating temperature and conveyed-air composition
Installation orientation, space and connection details
Electrical supply, control method and duty pattern
Sound, material and environmental constraints

Send project requirements