Title:
PRE-EXPANSION OF SELECTED PART OF HEAT EXCHANGER TUBE
Document Type and Number:
Japanese Patent JPS5956931
Kind Code:
A
Abstract:
This invention is a method for pre-expanding a heat exchanger tube prior to its insertion into a tube sheet. A tubular mandrel having an elastic bladder sheath sealed at each end is inserted into the tube and positioned at the point where the tube is to be expanded. A die with an annular recess approximating the shape to which the tube is to be expanded is clamped around the outer surface of the tube, concentric to the mandrel. The elastic bladder is then pressurized with hydraulic fluid pumped through a passage in the mandrel, thereby deforming the tube outward so that it conforms to the recess in the die. A heat transfer enhancement treatment thereafter may be applied to the exterior of the tube between the expanded sections, without concern that it may crack off when the tube is installed in a tube sheet. In addition, the hydraulic pre-expansion process prevents or minimizes cracking of the tube which sometimes occurs when a tube is expanded to an equivalent diameter in a single operation.
Inventors:
DONARUDO SHIRUBUESUTAA FUIIGEN
CHIESUTAA DOOSON UEAA
CHIESUTAA DOOSON UEAA
Application Number:
JP15176383A
Publication Date:
April 02, 1984
Filing Date:
August 22, 1983
Export Citation:
Assignee:
TRANE CO
International Classes:
B21D26/033; B21D53/06; F28F9/16; (IPC1-7): B21D26/02; B21D39/08; B21D53/08; F28F9/16
Domestic Patent References:
| JPS52130465A | 1977-11-01 | |||
| JP46025410A | ||||
| JPS4012122Y1 | ||||
| JPS5714428A | 1982-01-25 |
Attorney, Agent or Firm:
Narushima Mitsuo