Description

SAPSONS –  “A” Series Boiler Tube Expanders are straight-rolling, non-flaring tube expanders designed for expanding and sealing boiler tubes into tube sheets. These tools are widely used in boiler manufacturing, maintenance, and repair applications.

3 Rollers Parallel Tube Expanders, to suit plain Tubes Expansion of Boiler Tubes. To suit tubes of sizes ranging from 7/8″ O.D. to 4 1/2″ O.D. A range of models available to cover Tube Expansion Lengths of 1/2″ to 2.5/8″. Drum / Header / Short Series Mandrels available, to suit specific applications.

A Series tube expanders are among the most commonly used expanders for light- to medium-duty boiler work. They are designed for precision, durability, and ease of operation.

 Key Components :

1. Mandrel (Tapered Spindle)
   • The central rotating shaft with a tapered profile.
   • When rotated, it pushes the rollers outward.
2. Rollers (Usually 3 Rolls)
   • Hardened steel rollers placed around the mandrel.
   • They exert outward pressure on the tube wall.
3. Roller Cage (Body)
   • Holds the rollers in position and ensures smooth operation.
4. Thrust Collar / Stop
   • Controls the depth of expansion and prevents over-rolling.

Working Principle :

• The expander is inserted into the boiler tube.
• A drive tool (manual, pneumatic, or electric) rotates the mandrel.
• As the mandrel turns, the rollers expand outward.
• This presses the tube against the tube sheet hole, forming a tight mechanical bond.
• The process creates a leak-proof seal without welding.

Key Features :

• 3-Roller Parallel Expansion Design for smooth and uniform tube expansion.
• Suitable for plain tube expansion where flaring is not required.
• Designed for tube sizes ranging from 7/8 inch O.D. to 4½ inch O.D.
• Available in different models covering expansion lengths from ½ inch to 2⅝ inch.
• Offered with Drum Type, Header Type, and Short Series Mandrels to suit different boiler applications.
• Rugged, time-tested construction with rollers self-contained in the cage for durability and stable operation.
• Compatible with manual, pneumatic, or electric rolling drives.
• Manufactured using hardened alloy steel for long service life and consistent performance.

Applications :

These expanders are commonly used in:

• Fire-tube and water-tube boilers
• Boiler tube maintenance and retubing
• Heat exchanger tube expansion
• Re-rolling leaking tube joints
• Tube welding preparation and sealing operations

Typical Specifications :

• Tube outer diameter range: ~6 mm to 50 mm (varies by model)
• Number of rolls: 3 (standard)
• Drive: Manual or powered (pneumatic/electric)
• Materials: Alloy steel, heat-treated components

Advantages :

• Ensures strong and leak-tight joints
• Economical and reliable for parallel tube rolling
• Reduces maintenance and downtime / Reduces need for welding
• Ensures accurate and uniform expansion / Quick installation and removal
• Suitable for industrial boiler servicing and fabrication

Limitations :

• Not suitable for very thick tube sheets (heavy-duty expanders preferred)
• Requires skilled operation to avoid over-rolling
• Periodic maintenance of rollers and mandrel needed

SAPSONS describes the “A” Series as a sturdy and economical solution for applications where boiler tubes need expansion without flaring.