Extruded Fintube
Model B
produces a 5/8” high fin on tube sizes from 25mm to 1.5” ( 38.1mm). The Model B Extruded Finning Machine is now capable of 7/16” high integral copper fin at 7 to 10 FPI within the tube size range of the machine (25mm and 1.5”).

Model 2A produces a 5/8” high fin on tube sizes from 1" to 2” ( 50.8mm)

Fin pitch may vary between 5 and 11 FPI when tooled with the specific discs. Both of these machines are capable of producing integral high fins, as well. Each machine is configured for the specific production requirements of the end user.

  
Machine Service After Sale
• Technical support
• Training at your site or in McElroy's plant or both.
• Periodic updates on the latest R&D
• Information on maximum production criteria
• Reference charts
• Specifications for tube and aluminum muff
 
     

General:
The extruded fin is formed from an outer aluminum tube with a large wall thickness (muff), which is aligned over an inner base tube. The two tubes are pushed through three arbors with rotating discs that literally squeeze or extrude the aluminum fins up and out of the muff material in a spiral shape in one operation. The resultant fin typically has a base or root thickness of .035”, average fin thickness .016” and a tip of .009”, with an overall height of 16mm (5/8”). The root thickness serves to form an uninterrupted bond over the entire tube length.

McElroy disc technology now makes it possible to fin thinner muff thus offering significant material savings. Recommended standard muff wall is .176” as opposed to industry practice of .183”-.210” In addition, the same growth factor can be used for pitches from 8 - 11 FPI, allowing for standardization on one muff thickness and eliminating the need to stock multiple muff wall thicknesses.

     
Machine Specifications
Length: 33.83 Meters (111 Feet)
Width: 9.4 Meters (30 Feet)
Max tube length: 15.2 Meters (50 Feet)   Extensions available for up to 18.3 Meters (60 foot tube)
Power Requirement: At 100% RPM, the machine pulls 102-105 amps.
Horsepower: 150 HP AC Motor
Isolation Transformer: 200 KVA; 50-60 Hz; Meets incoming plant voltage and steps up or down to provide 460V.
Manpower: One full-time operator, one disc stacker, and two helpers.
 
Extruded Fin Specifications
Fin Material: Aluminum 1060-F; 1050-F; 6063-0. Physical properties can vary considerably and should be controlled. Suppliers should be given specific information to control OD and ID and to hold maximum yield to below 7500 PSI.
Max Fin Height: 5/8"
Linear Tube Material: No theoretical limits.
Production Rate: Production Rate 5/8 X 10 X 50': 885 feet per hour.
Cruising RPM 2800, Max tube RPM 3600. (85% efficiency)
Type of Service: Generally used for more severe duties, especially if corrosion and thermal cycling is a problem.
Temperature: Typical Acceptable Tube Wall Operating Temperature
United States: 450° F (230° C) 
European: 480° F (250° C)
Advantages: Liner tube incased in aluminum for maximum corrosion protection.
Disadvantages: Use more material per foot of tube than W/O (58% more), OLFF (41% more), or Imbedded Fin (78% more).
 
Model B & 2A Features
Liner Tube Rack with Tube Descrambler:
Designed to store the liner tubes before cycling through the cleaning line. Holds up to 91, 1" tubes.

Liner Tube Cleaning Station:
Clean straight tubes with a normal amount of oil or rust can be cleaned by this system. Consists of a wash and a rinse tank. The heated 70-gallon wash tank is equipped with 8 spray nozzles and 1.5 HP centrifugal pump. The rinse tank consists of 4 spray nozzles powered by available water pressure. Movement of the tube from the liner tube rack through the cleaning station is controlled by Capstan #1, which is equipped with hardened steel drive wheels driven by special low friction hydraulic motors.

Liner Tube Polishing Station:
Enclosed steel frame assembly includes dust collector and four contoured 3M polishing wheels powered by four 3 HP electric motors. Polishing wheels are spring loaded against an adjustable “stop” with a shock absorber to reduce vibration and bounce off the wheels. Capstan #2 between the Liner Tube Polishing Station and the storage rack is equipped with urethane wheels and propels the clean, polished tube into the storage rack.

Liner Tube and Muff Storage Rack:
Designed to store the clean liner tubes traveling from the cleaning line and the straight aluminum muff tubes. Muff tubes are loaded by hand from the back of the storage rack. The top level of the rack is padded for straight muff tubes and the lower rack receive the cleaned liner tubes.

Input Rack:
Consists of 2 feed barrels. One of the barrels is accessible to the operator for loading, while the other is aligned to the finning head. A semi -automatic hydraulic pusher assists the operator in loading the muff and liner tube into the barrel.

Fin Head:
The fin head weighs approximately 7000 pounds. The fin is formed by three sets of driven discs running tangent to the tube and skewed to conform to the appropriate helix angle. Approximately 30 discs are mounted on each of the three arbors.

Advantages and Special Features of Fin Head:
  • Helix angle can be adjusted in 15 to 20 minutes.
  • Easily adjusted for the incremental tube sizes of the machine.
  • Arbors are not on fixed centers.
  • Gitts oiler applies positive oil pressure to the outer arbor shaft seal chamber, which keeps the sleeve-type aluminum arbor bearings free of contamination.
  • Coolant nozzles are specially designed to evenly distribute coolant to the working area of the discs.
  • Crashes can be cleared quickly.
  • Positioning of arbors is repeatable and minimizes trial and error settings.

Finned Tube Rack:
To properly support and convey the finned tube, the machine has been equipped with quick-change steady-rest type roller conveyors. The rack is mounted on guide rollers, which allows a hydraulic cylinder to move the upper rack portion 36” along the tube centerline. This movement enables the finned tube to be withdrawn from the finning head and opens a passageway between the machine and the Finned Tube Rack. One of the three sets of rollers is mounted on a hydraulically actuated pivot arm, which permits the finned tube to exit the rack and roll onto a storage ramp. On the end of each tube storage ramp arm is a “V” roller, which permits the tube to be easily guided into the end stripper.

In Line Pressure Washer:
Cleans finned tube as it exits the fin head.

Coolant System:
The finning operation demands a great amount of coolant with a high degree of lubricity directed at the working area of the finning head. A 330-gallon tank is provided along with a ¾ HP, 40 GPM centrifugal pump. The coolant tank is set in a pit 34” deep to allow gravity return flow to the 80-micron tank filtration unit, which sits atop the tank.

End Stripper:
One end stripper is stationary near the fin head and the second is on casters for easy positioning down the finned tube rack to minimize tube handling. The stripper is a unique McElroy design, which quickly strips the fins from the end of the tube. Strip back amount is dependent upon customer design. Maximum strip back 6”. The two jaws, at right angle to the tube, contain replaceable tool steel blades which cut through the aluminum fin but stop short of the liner tube. The cylinder on the tube centerline pushes the liner out of the finned portion captured by the jaws.