Engineering Reference Case Profile · Drying, Heat Treatment & Ovens
Industrial Drying, Heat Treatment and Ovens · High-Temperature Duty, Bearings and Second-Source Qualification
Compiled from LONGWELL’s real correspondence with heat-treatment and semiconductor/PV furnace builders, textile flash-dryer OEMs and drying-equipment developers in China, Germany, the USA and France. Three things decide these programmes: the fan has to survive continuous radiant heat, the buyer is almost always qualifying a second source against an incumbent European fan, and the qualification is won on documents as much as on the sample.
About this case profile: This profile is compiled from real LONGWELL project correspondence in this segment. Customer names, commercial terms and pricing are withheld; company names and branding have been removed from the photographs. Model numbers, electrical ratings and dimensions are quoted from LONGWELL controlled datasheets, product nameplates and customer-approved drawings. Where a figure is a typical range rather than a measured project result it is labelled as such. Named references are available under NDA on project qualification (sales@longwellfans.com).
1 · Challenge
- Radiant heat kills sleeve bearings. On a quartz flash-dryer, the previous fan used sleeve bearings; continuous radiant heat caused oil migration and noise. The fix is a double ball bearing motor, decided at selection rather than after the first failure.
- Second-source qualification is judged on the datasheet. Industrial equipment buyers evaluating an alternative to an incumbent European fan require the full pack — P–Q curve, dimensions, wiring, protection functions — delivered with the sample, not after it.
- Diameter is not the selection. A 250 mm frame at 240 W does not replace a 250 mm frame at 500 W. Matching rated power and speed matters more than matching the wheel diameter.
- Closed-loop control is normal. PLC-driven dryers need 0–10 V speed control plus a tachometer / FG output for closed-loop monitoring — a detail that is easy to leave out of a first quotation and expensive to retrofit into a harness.
- Voltage variants are a trap. 115 V and 220 V versions of the same cross-flow series look identical; one mis-shipped sample cost a project cycle.
- Boundaries have to be drawn. Customers sometimes ask for 5–8 kW heating elements to be integrated into the fan. That is a system split, not a fan feature.
2 · Solution architecture
These programmes are run as qualification projects. LONGWELL supplies the EC centrifugal and cross-flow candidates together with the complete technical pack, matches rated power and speed rather than wheel diameter, specifies ball bearings by default where radiant heat is involved, and where the customer has a local engineering site, arranges in-country machine testing with the data reported back to head office — which removes weeks of international sample shipping from the schedule.
Selections supplied into drying, heat treatment and ovens
| Model | Ratings | Control / construction | Application |
|---|---|---|---|
| 500 W-class EC backward-curved (250 mm frame) | 230 VAC (200–270 V), ≈3,740 rpm, targeting 1,355 m³/h @ 733 Pa | 0–10 V / PWM, FG feedback, soft start, stall protection, constant-power control at high pressure; IP44/IP54 | Semiconductor and PV heat-treatment equipment |
| LWBE250-AO | EC backward-curved, 250 mm | CE certified (LVD and EMC) | Furnace and heat-treatment equipment |
| LWCA090-500 | 220 V, 50/60 Hz, 1.2 A, 250 W, 2,500 rpm, 1,400 m³/h, 73 dB(A) | −20 °C to +70 °C, insulation B/F/H, ball or sleeve bearing | Furnace and oven air circulation |
| LWCD-401055MN-06 | 24 V DC, 0.3 A, 2,000 rpm, 311 m³/h | 0–10 V from PLC (red +24 V, black −24 V, white signal), tacho output available | Dryer air path |
| LWCD-601100MN-06 | 24 V DC, 1.3 A, 1,800 rpm, 857 m³/h | 0–10 V from PLC with added tachometer lead | Dryer air path, closed-loop monitored |
| LWCA-06018D23B | 220 VAC cross-flow, 250–300 CFM band | Double ball bearing recommended for radiant heat | Quartz flash-dryer for textile printing |
| 110 V cross-flow with heater module | 110 V, 50/60 Hz, 160 m³/h | UL certification documents supplied | Sanitising / drying terminal equipment |
3 · Verified figures
Fan performance figures are quoted from LONGWELL controlled datasheets and product nameplates and are tested per AMCA 210/211 methods; third-party reports available on request. EC versus AC energy saving is approximately 30%, higher under strongly varying load — confirm against your own load profile. Final selection must be confirmed against the actual duty point (airflow, static pressure, ambient temperature, certification scope) of your machine.
Qualification target duty
1,355 m³/h @ 733 Pa
500 W-class EC selection matched to the incumbent P–Q curve
Sample turnaround
7–10 days
High-power 250 mm EC sample built for second-source qualification
Oven circulation fan
1,400 m³/h at 250 W
LWCA090-500, 2,500 rpm, 73 dB(A), −20 °C to +70 °C
Flash-dryer airflow band
250–300 CFM
7.07–8.50 m³/min, against a 14.4 kW three-phase quartz halogen heat source
Bearing decision
Double ball bearing
Specified by default where continuous radiant heat is present
Certification on file
CE — LVD 2014/35/EU and EMC 2014/30/EU
LWBE250-AO to LWBE450-AO, tested to EN 60335-2-80, EN 60335-1, EN 55014-1/-2, EN IEC 61000-3-2/-3-3
Closed-loop feedback
0–10 V + tachometer
PLC speed control with FG output for closed-loop monitoring
4 · How these programmes run
Incumbent pack reviewedThe customer’s existing fan datasheet is read for rated power and speed first — not wheel diameter. This is where most mis-selections in this segment start.
Heat path assessedIf the application involves quartz heaters, furnaces or enclosed high-temperature spaces, ball bearings and insulation class are raised before the first quotation.
Control scope definedSpeed control method plus whether an FG / tachometer output is needed for closed-loop PLC monitoring; leads are defined on the drawing.
Sample plus full packSample built (7–10 days for a high-power EC unit) and delivered with the complete datasheet, curve, dimensions, wiring diagram and protection functions for the qualification file.
Local machine testWhere the customer has an engineering site in China, samples are tested in the actual machine there and the data is reported to head office, removing international shipping from the loop.
Voltage and nameplate checkBefore despatch, the voltage variant is checked against the order. On a 115 V / 220 V series this check is mandatory.
5 · Engineering lessons carried forward
- Match rated power and speed, not wheel diameter. A 240 W fan in a 250 mm frame will not replace a 500 W fan in a 250 mm frame, and finding that out in the customer’s machine costs a qualification cycle.
- Specify ball bearings where radiant heat is continuous. Sleeve bearings in front of quartz heaters migrate oil and become noisy; raise this at selection rather than treating it as a warranty issue later.
- For second-source qualification, the datasheet is part of the sample. Curve, dimensions, wiring and protection functions have to arrive together, or the sample sits in the customer’s queue waiting for paperwork.
- Ask whether a tachometer or FG output is needed. PLC-controlled dryers frequently close the loop on fan speed, and adding the lead after the harness is designed is far more expensive than including it.
- Where the customer has a local engineering site, test there. In-country machine testing with data reported to head office removed weeks of sample shipping and time-zone delay from one German programme.
- Draw the system boundary early. Integrating a 5–8 kW heating element is not a fan-manufacturing function; proposing an external heater module keeps the project moving instead of stalling on an impossible request.
- Enforce a voltage and nameplate check before despatch on any series that exists in both 115 V and 220 V.
6 · Project evidence
Every item below is a real project thread from LONGWELL’s own correspondence. Each carries an anonymised case reference, the counterparty described by industry and buying role only, an evidence grade, the actual dates from first contact to close, the length of the email thread and, where an invoice is on file, the order value band. Customer names, domains, brand artwork, prices and commercial terms are withheld — including from the photographs. Evidence grade A means controlled documents or test reports are on file for that thread; grade B means a structured enquiry and specification are on file. Order value bands are read from the proforma or commercial invoice held on file and rounded to a band, in the currency as invoiced; many threads on this page are sampling or qualification stages, where the recorded value is a sample order rather than the series volume. Unit prices are never published.
500 W-class EC second source for heat-treatment equipment
- Target: 230 VAC (200–270 V), 500 W class at ≈3,740 rpm, reaching or approaching 1,355 m³/h at 733 Pa, IP54, with 0–10 V/PWM control, FG feedback and constant-power control at high pressure.
- The customer’s own first pick — a 240 W fan in the same 250 mm frame — was short on both power and pressure. Engineering moved to a higher-power, higher-speed EC platform, strengthened the impeller and balance, and matched the P–Q curve to the incumbent.
- A high-power 250 mm EC sample was built in 7–10 days and delivered with the full qualification pack; cross-flow specifications were supplied in parallel for the rest of the machine.
PLC-controlled dryer with closed-loop speed feedback
- LWCD-401055MN-06 (24 V DC, 0.3 A, 2,000 rpm, 311 m³/h) and LWCD-601100MN-06 (24 V DC, 1.3 A, 1,800 rpm, 857 m³/h), driven from the customer’s PLC over 0–10 V.
- Standard 0–10 V wiring was defined explicitly (red DC24 V+, black DC24 V−, white signal), and after testing a tachometer output lead was added to LWCD-601100MN-06 for closed-loop monitoring.
- The customer’s initial request to integrate a 5–8 kW heating element inside the fan was answered by splitting it out as an external heater module — outside a fan manufacturer’s technical boundary.
Semiconductor / PV furnace builder — tested locally, approved in Germany
- LWCA090-500 AC shaded-pole cross-flow (220 V, 50/60 Hz, 1.2 A, 250 W, 2,500 rpm, 1,400 m³/h, 73 dB(A), −20 °C to +70 °C, insulation B/F/H, ball or sleeve bearing) and LWBE250-AO EC backward-curved, both CE certified.
- Rather than shipping samples to Germany, samples went to the customer’s own Kunshan plant for testing in the actual machine, with the data reported back to head office for approval — cutting the verification cycle substantially.
- The CE certificate below covers the LWBE250-AO to LWBE450-AO range against the Low Voltage Directive.
Quartz flash-dryer — bearing upgrade after field noise
- Duty: 275–300 CFM (7.79–8.50 m³/min), 250 CFM minimum, at 220 VAC, working alongside a 14,400 W three-phase quartz halogen system that flash-dries ink in 1.5–3 seconds, circulating air through a stainless mesh filter.
- A 115 VAC sample had been shipped in error against a 220 VAC requirement, costing a project cycle; the correct 220 VAC LWCA-06018D23B was reissued and a mandatory voltage/nameplate check introduced before despatch.
- The customer’s existing sleeve-bearing motor produced noise under continuous radiant heat; the recommendation was a double ball bearing motor for this duty.
110 V UL-certified cross-flow with heater module
- Tangential fan at 110 V 50/60 Hz delivering 160 m³/h, with UL certification required and a matched warm element.
- A matching 110 V selection was made to the customer’s internal space envelope, UL documentation supplied to shorten the approval cycle, and six sample sets built for testing.
Fan performance figures are quoted from LONGWELL controlled datasheets and product nameplates and are tested per AMCA 210/211 methods; third-party reports available on request. EC versus AC energy saving is approximately 30%, higher under strongly varying load — confirm against your own load profile. Final selection must be confirmed against the actual duty point (airflow, static pressure, ambient temperature, certification scope) of your machine.
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