In this paper, the hybrid tube expander unit for fin and tube type heat exchanger are developed by means of enlarging and inserting the smooth tube with a small diameter to a finned tube having larger diameter. In other word, the tube expander tool that is easy to attach and remove from tube is developed. The hybrid tube expander unit developed in this study can move easily and enlarge the tube without fixing at tube sheet. Also, this unit has a function removing scales inside tube by replacing a tube expander ball.

Abstract
 1. 서론
 2. 본론
  2.1 확관율
  2.2 감소율
 3. 확관유닛의 운전결과
  3.1 확관율 운전 결과
  3.2 감소율 운전 결과
 4. 결론
 참고문헌

• 노건상(동명대학교 공과대학 냉동공조공학과) | Roh, Geonsang
• 김종남(런텍) | Kim Jongnam