Trade.Information

Product Name: Paddle Wheel (PW)

Product Description

High-Temperature Centrifugal Fans

For continuous, reliable operation in high-temperature applications
Performance Ratings

Robinson PW fans are furnished with radial bladed wheels specifically suited for applications involving continuous operation at temperatures from 70° F to 2000° F. PW units are often constructed of special alloy materials for high-temperature service, but are also used for low temperature operations. Other Robinson fans designed for high-temperature applications include axial flow and FC (forward curve) blade series.

Robinson’s PW design is a result of thorough and exacting laboratory testing and documented performance ratings. These ratings were calculated on the basis of complete fan units, including wheel, casing and inlet section.

Components are also furnished separately by Robinson, but the fan unit must be set up with wheel, shaft, casing, inlet and all other components in place to Robinson design specifications to achieve rated performance
Series
Temperature (Max)
Class 300 300º F
Class 700 700º F
Class 900 900º F
Class 1000 1000º F
Class 1300 1300º F
Class 1450 1450º F
Class 1550 1550º F
Class 1700 1700º F
Class 1800 1800º F
Class 2000
& Above *
Design Considerations

PW fans may be furnished as either non-insulated or full-insulated units.

PW fans are also offered with an insulated plug and non-insulated housing. In this type of construction, the non-insulated housing is usually mounted on the inside wall of the furnace or oven.'

All Robinson PW Series are available in fan arrangement numbers 1, 2, 4, 8 and 9. Flexibility in design also allows Robinson to offer both round and square plugs to accommodate a wide range of furnace requirements. Other capabilities include gas-tight designs.

For reliable, efficient service, Robinson has always stressed the importance of preventive maintenance. Fan casings are therefore designed with either plug-type housings or split housings for accessibility to the wheel of servicing and/or removal
Optional designs include inlet and outlet flanges, split housings, inspection doors, inlet or outlet dampers and insulation studs.

Quality Control

Dye-penetrant testing, ultrasonic testing, vibration analysis, X-ray testing, computer finite element stress analysis and, in some cases, magnetic-particle inspection are utilized to ensure that the PW series fans meet Robinson’s stringent quality-control requirements. Other steps taken to ensure long fan life include dynamic balancing of the wheel and shaft assembly on independent, computerized equipment. Full-scale mechanical testing is performed on the assembled PW unit (when possible) prior to shipment.

Fan Repair and Field Service
Robinson field service representatives are available for troubleshooting, field balancing and diagnostic inspection of fans and other types of rotating equipment. These personnel supervise certain on-site repairs or, if necessary, determine whether the unit must be factory repaired.

Robinson repairs and rebuilds PW units as well as types of industrial fans, regardless of original manufacturer. In addition to fan repair as a cost-saving alternative, Robinson redesigns and upgrades existing air-moving equipment to increase capacity and improve efficiency.

Robinson PW Drive Arrangements
Arrangement 1
PW fan arrangement for either V-belt or direct drive, depending on customer specifications.

Sizes: 15-5/8" to 71-¼"

Temperature range: 70° F - 2000° F
Arrangement 2
PW arrangement for attachment of bearing base to plug, typically utilized in mounting fan unit to sidewall or roof of furnace or oven. Fan may be belt drive or direct connected. This design can be furnished with either flange or pillow – block bearings.

Sizes: 15-5/8" to 71-¼"

Temperature range: 70° F - 2000° F
Arrangement 2
PW arrangement for attachment of bearing base to plug, typically utilized in mounting fan unit to sidewall or roof of furnace or oven. Fan may be belt drive or direct connected. This design can be furnished with either flange or pillow – block bearings.

Sizes: 15-5/8" to 71-¼"

Temperature range: 70° F - 2000° F
Arrangement 8
PW fan arrangement for direct connected service. Robinson unit includes motor base in addition to standard bearing base.

Sizes: 15-5/8" to 71-¼"

Temperature range: 70° F – 2000° F
Arrangement 9
PW fan arrangement for V-belt with bearing base to receive drive motor and adjustable motor base for proper drive tension.

Sizes: 15-5/8" to 71-¼"

Temperature range: 70° F - 2000° F
PW Fan Housing Construction

Designed for efficient service, Robinson housings are fabricated from a wide range of materials to meet application requirements of temperature and/or corrosion. Housings feature welded construction and fabrication tolerances are closely monitored.

In situations involving fan-related expansion, Robinson PW housing units are designed to consider thermal expansion. Attached inlet and outlet duct connections must allow for expansion. Depending on various factors, this expansion allowance may be provided by the use of slip joints or fabricated expansion joints. Factors that affect thermal expansion design include fan size, attached duct location, design and type of system; i.e., whether or not it is gas tight. Expansion joints are offered by Robinson as optional items or may be provided by other suppliers.

PW fan housings are furnished by Robinson in both non-insulated and fully insulated construction. Plug-type or split housings are available for both non-insulated or fully insulated designs. Plugs are constructed to both round or square designs, but round plug units are furnished by Robinson unless otherwise specified
As required, housings may be furnished separately for mounting on the inside surface of the furnace/oven or kiln. In this situation, they are available with or without a sleeve, depending on customer preference.

Due to handling and shipping requirements, it may be necessary to ship some of the sizes knocked down for erection at the site. Please refer to the certified fan drawing for that information.

Fan equipment built for explosive, gas-tight or highly corrosive applications requires special construction features. For explosive service, these include nonferrous construction and grounding of components. Gas-related applications require gas-tight mechanical seals. Water-cooled shaft and water pads are often used to dissipate heat buildup.

Robinson has extensive experience in building fans for highly corrosive environments. A wide range of alloys and special metals are used in the construction of PW units for this type of service. A special surface treatment is also offered by Robinson for high-temperature fans used in certain conditions.

Housings are available in the following outlet designs:

Single Outlet – Multiple Discharges 1
Double Outlet 2
360-degree Diffuser 2
Notes:
1. Performance ratings on this site are for Robinson’s single outlet design.
2. Performance ratings available upon request for other two outlet designs.

Wheels

PW wheels are carefully engineered by Robinson to provide optimum performance while maintaining the integrity necessary for demanding high-temperature service requirements.

Finite element stress analysis procedures are used to design the wheels for a wide range of size, temperature and speed requirements. From this information, selections are made regarding types of materials to be utilized in wheel construction as well as thickness of the materials.

In the engineering data section of this bulletin are listed limiting speeds for fan size and temperature conditions. Requirements falling outside of these parameters are also possible, pending approval of Robinson’s engineering staff.

Shafts

Shafting is solid and machined to meet applicable bearing tolerance and wheel-fit tolerance requirements. Alloy shaft are utilized in high-temperature situations.

Set-screw and key method is used for standard wheel and shaft attachments. A weld wheel-to-shaft attachment design is sometimes recommended by Robinson if certain temperature, speed, size and mounting arrangements dictate the need for it. Shafts are furnished with heat flingers to protect fan bearings as required.
Bearings

Depending on equipment size, speed and temperature, either ball, roller or sleeve bearings are used in PW fan construction. Either heavy-duty pillow-block or flanged-type bearings are furnished by Robinson, depending on the application. Grease is the standard lubrication for ball and roller bearings
Automatic grease systems are also available for bearing lubrication. For oil-lubricated bearings, static oil is the standard lubricant, although circulating oil and oil mist systems are also available
Shaft Seals

For applications requiring shaft seals, standard gasket seals are normally furnished with materials to suit the application.

Other types of specialized seals are available for more demanding service, including gas-tight applications. Shown is a positive packing gland of alloy construction with adjustable features.
Accessories

Optional accessories and design modifications include discharge drains, inlet and outlet flanges, inspection doors, inlet or outlet dampers and insulation studs. These accessories are standard on some Robinson PW models depending on the application recommended by Robinson engineers for fans used in certain conditions.
Centrifugal fans for high-temperature recirculation
Air performance and sound testing

Research engineers and technicians use modern instrumentation to ensure accurate test results in accordance with strict testing.

Mechanical and dynamic testing
Robinson engineers can utilize strain gauge technology to compare actual operating stresses of rotating fan wheels to theoretical finite element analysis.

Nondestructive testing
The emphasis on quality on Robinson is backed by expert workmanship and a thorough quality control program. Nondestructive testing techniques used by Robinson include:

Computer finite element stress analysis
Magnetic particle inspection
Ultrasonic testing
Dye-penetrant testing
Radiographic (X-ray) testing
Vibrational resonance testing using dual-channel real-time analyzer
Dynamic strain gauge testing

Company Details

Robinson Industries Inc., based in Zelienople, PA, is the leading manufacturer of custom-engineered and custom-built industrial fans in North America, with sales extending worldwide. With four U.S. locations, Robinson Industries works in a... more