Tube Extraction Technology

About Colmac Coil
Colmac Coil is a third generation, family-owned company founded in 1971 that has grown to be one of the world’s leading manufacturers in new and replacement refrigeration coil markets. They specialize in custom fin and tube heat exchangers with the majority of business focused on industrial refrigeration. Colmac Coil is based out of Colville, Washington with an additional manufacturing facility in Paxton, Illinois and a South American sales office in Guadalajara, Mexico. Their mission is to provide heat transfer and refrigeration markets worldwide with products that are innovative, built to customer specifications, and shipped on-time, with fast friendly service for the mutual benefit of customers, employees and shareholders.

Background
Colmac Coil produces fin and tube heat exchangers with a hydraulic expansion process. The tubes are fed through the stamped coil sheets to form a loose assembly. Then a plug larger than the diameter of the tube is inserted and hydraulic pressure forces the plug along the tube. This expands the tubes within the stamped coil sheets forming a mechanical bond for structural support and heat conduction. The expansion process is not foolproof however, the tubes can rupture and require replacement. The partially expanded tube must be extracted with minimal damage to the coil pack or else the entire assembly will have to be scrapped.

Problem Details

 * Colmac Coil will fully expand the ruptured tube from the other end to eliminate the transition for our tool
 * A winch used for later operations can be used to drag a tool down the tube
 * Tube material is 3003 Aluminum seamless
 * Tubes will be 5/8", 7/8", and 1"diameter and up to 30 feet in length
 * The device and process must be successful on every attempt to prevent scrap
 * Process must take less than 1 business day to complete tube removal
 * Tool must not drag or severely damage heat exchanger fins
 * Safety is of utmost concern and extraction process should not endanger workers

Tool Requirements:

 * Tool set must cost less than $6,000
 * Replacement parts must be commercially available
 * Must be able to cut a wall thickness of .065" to .085"
 * Low maintenance
 * Tool must be able to attach to existing winch cable

Team Goals

 * Target removal time of less than 2 hours
 * Separate tools for each tube size

Deliverables

 * Prototype removal tools
 * Demonstration of tool on Colmac test coils
 * Detailed report discussing reason for choosing final design tool, tool usage and maintenance instructions, and a self-evaluation of this product