310101c Tube Bending and Tube Joining

Tube Bending and Tube Joining ILM 310101c

Objectives

• Identify different types and sizes of tube and tube fittings

• Understand common tools and techniques for tube joining

• Learn common tools and techniques for tube bending

• Calculate bending lengths for various tube configurations and angles

• Identify hazards related to tube fitting selection and installation

Overview of Tubing

• Tubing: A long hollow cylinder for moving fluids or protecting cables

• Uses of tubing:

  1. Mechanical tube

  2. Pressure tube

  3. General purpose tube

Types of Tubes

Mechanical Tube

• Available in various shapes and sizes

• Not designed for internal pressure

• Used mainly for construction and protection

Pressure Tube

• Designed to carry fluids and gases

• In instrumentation, used for instrument air to actuate instruments

• Impulse lines connect measuring instruments

• Common materials include:

  1. Copper

  2. Steel

  3. Thermoplastic

Copper Tube Specifics

• Primarily used in plumbing and HVAC systems

• Standards set by ASTM for 99% pure copper

• Six standard types identified by color coding:

  • Type K: Green - Use: Domestic Water Service, Distribution, Fire Protection

  • Type L: Blue - Use: Similar to Type K but different applications

  • Type M: Red - Similar to Type K but lighter applications

  • DWV: Yellow - For Drain, Waste, and Vent

  • ACR: Blue - For Air Conditioning and Refrigeration

  • OXY/MED: Green/Blue - For Medical Gases, Compressed Air

Sizing and Types of Tube

• Size determined by OD (Outside Diameter)

• Temper types:

  • Drawn Temper: Hard or rigid

  • Annealed Temper: Soft and flexible

Tube Fittings

• Types of fittings:

  1. Flare fittings

  2. Flareless fittings

  3. Soler fittings

Flare Fittings

• Consists of nut, sleeve, and body with a flared end

• Requires a flaring tool for preparation

Flareless Fittings

• Consist of a ferrule with sharp leading edges

• Seal made between ferrule and body;

  • They may develop leaks over time

Mechanical Grip Flareless Fittings

• Two ferrule design:

  • Back ferrule grips tubing as the front ferrule polishes it

  • Produces a secondary seal

Push-in Fittings

• Use O-ring for gripping the tubing

• Requires tubing softer than the O-ring material

Proper Fitting Tightening

• Hand-tighten the nut then 1 ¼ turn

• Check proper torque and tubing position

• Use a gap gauge (NO GO Gauge)

Solder and Soldering

• Solder: A metal alloy melting between 90-450 °C

• Used to join metallic surfaces through soldering

• Alloys melting above 450 °C termed brazing

• Commonly now lead-free; can contain flux

Copper Tube Soldering

• Tin/lead solders available with varying tin concentrations (5-70%)

• Higher tin concentration increases tensile and shear strengths

• Common alloys:

  • 50/50 Tin/Lead melts at 215 °C

  • 60/40 Tin/Lead melts at 188 °C

Soldering Equipment

• Torch: Small propane for general, air acetylene for higher temperatures

• Solder: Typically tin/lead alloy

Flux

• Cleaning agent to remove oxidation during soldering

• Prevents oxide layer formation during heating

Steps for a Good Solder Joint

1. Cut tube to length & deburr

2. Clean tube ends; apply flux

3. Clean fittings; apply flux

4. Assemble and support

5. Heat uniformly and solder

6. Allow to cool & clean excess flux

Capillary Action

• Definition: Liquid’s ability to flow against gravity in narrow spaces due to intermolecular forces

• Important in soldering to ensure filler penetrates joints

Self Test and Assignment

• Review the material covered for practical understanding and application.