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"...Pictured above is a unique application where an API-560 specified fan was installed in a chemical plant. Most industrial/chemical plants have not used such strict design considerations on their critical service fans..." Ron Bennett, sales engineer, r. w. bennett co.

Clarage Fan Company (A Twin Cities Fan Company, formerly Zurn Industries, Air Systems Division) has engineered, designed, and fabricated a special industrial critical service fan to be built to the strict American Petroleum Institute (API-560) specification, and then installed in an industrial/chemical plant. A well know, Midwest Fortune 500 chemical company had a need to replace a 20 year old major brand 300 horsepower direct drive critical service fan that had developed vibration problems, AND which had been designed for excessive outlet damper volume static pressure control--a common design practice years ago.

The fan was in use 24 hrs 6 days a week with one half day out of service for general dryer fan inspection and or system maintenance. It was also located in an operator restricted (hazard duty) area where the fan could not be observed. Therefore continuous operation of the fan was paramount. Clarage fan engineers MATCHED the existing fan outlet, centerline height, fan inlet, fan housing dimensions, and the general foundation pad, thus eliminating thousands of dollars of retrofit duct work expense (and dryer) inlet/outlet modifications. By looking at the customers new fan system requirements (same volume but much less static pressure than was designed for 20 years ago) Clarage was able to select a new radial tip (material handling) wheel that fit this MATCHED housing, AND reduce the direct drive speed from 1780 rpm to 1180 rpm. This further reduced the fan motor horsepower from 300 BHP to a 200 VFD BHP motor. The resulting electrical savings on the new fan/motor combination is "...approximately $20,000 a year..." Direct quote per specifying engineer and purchaser.

Clarage is THE recognized market leader in API installations. BUT this is just one of a few used in a pure industrial application. The design intent of API-560 (and its counterpart API-673) as stated from the strict specifications (to which Clarage will take NO exceptions) reads as follows: 'DESIGN. GENERAL - The equipment...covered by the standard shall be designed and constructed for a MINIMUM service life of 20 years, AND at lest 3 years of uninterrupted operation...' The installed fan shown above also had the following innovative design considerations: Tubular Base Design. Clarage recognized that in order to achieve a minimum design resonance of 1.2 times operating speed of the fan it would be necessary to include the stiffness of the base (AMCA arrangement 8) in the calculations and that the base would require up to 3,000,000 lb./in horizontal stiffness. To achieve this level, Clarage designs a tubular base with a rectangular cross-section and thick tube-wall. The resulting base provides trouble free (resonance free) operation, even with motors in excess of 800 HP. This gave the specifying engineer more options, and less support concerns for his existing fan foundation (that was 60 feet in the air, and on which maintenance would be very expensive). The fan base is also of a machined design.

The fan has high lateral rigidity, column support, shimming/grouting is only required under pads. Vertical jacking screws were provided. Stainless steel fan construction was provided, A factory mechanical run test was provided. An optional field or factory performance test was offered. Zero leakage .John Crane' fan seal was provided.

The customer's 200 HP VFD motor was factory mounted to fan base and fan rotor was shop balanced. Clarage provided and mounted a Holset torsional spacer coupling for future use in rotor or motor removal. To further assist the system design, the existing fan opposed blade damper and operator was reused and matched to the fan outlet. The retained outlet damper was critical only for start up and system volume balance at low rpm. When the new fan was installed, and the fan was running at normal operating conditions, the outlet damper was able to move from the previous 70 % closed..to full open, improving the fan static efficiency greatly.

The fan was built on time and the project was finished under budget. The unique stiffness of the fan assembly allowed the unit to be picked up as one piece and lifted in place. The fan has been in operation for several months, trouble free. All customer suggestions and any manufacturing or design concerns were handled through Clarage ISO-9001 format--- to the full satisfaction of the customer.

The fan has customer specified, and their plant standard roller bearings, special seals, full bearing temperature and vibration indication. Although the customer has permitted Clarage to use these pictures of their industrial installation, they do not wish to have their name published on the Internet.

For more information contact the r. w. bennett co., inc at ronwbennett@yahoo.com or contact Clarage through the link at our site. If your company has a critical service existing fan that needs modification, or new fan requirement that you would like us to review for API consideration-- OR even to be considered with our STANDARD heavy duty industrial designs, please contact us.

Submitted by Ron Bennett. Manufacturers' representative for Clarage Fan Company. r.w.bennett co., inc. Prospect (Louisville) Kentucky. 502-228-3888. (FAX: 502-228-4415) 24 hr cell contact: 502-767-5415.