Automatic tube expander for a heat exchanger

Claim 1

An apparatus for expanding heat exchanger tubes of various length heat exchangers, comprising: a frame; a plurality of tube expanding rods; a rod pusher slideably connected to said frame and said tube expanding rods, said rod pusher providing a driving force to push said rods through said heat exchanger tubes, thereby radially expanding said tubes into an interference fit against a plurality of heat transfer fins traversing said tubes; a plurality of flaring sleeves slidably disposed around said plurality of rods and being adapted to further radially expand an end portion of said heat exchanger tubes beyond the extend to which said rods expand said heat exchanger tubes; a flaring sleeve pusher slidably disposed around said plurality of rods and adjacent to said plurality of flaring sleeves, said sleeve pusher being adapted to push said plurality of sleeves into said end portion of said plurality of heat exchanger tubes under said driving force of said rod pusher; an adjustable stop positioned to mechanically limit the travel of said plurality of rods and said plurality of flaring sleeves with respect to said frame; a stop drive coupled to said adjustable stop for automatically repositioning said adjustable stop; and a control for controlling said stop drive in response to an input representing various lengths of said heat exchangers to be acted upon by said apparatus.

Claim 2

An apparatus for expanding heat exchanger tubes of various length heat exchangers, comprising: a frame; a plurality of tube expanding rods; a rod pusher slideably connected to said frame and said tube expanding rods, said rod pusher providing a driving force to push said rods through said heat exchanger tubes, thereby radially expanding said tubes into an interference fit against a plurality of heat transfer fins traversing said tubes; a plurality of flaring sleeves slidably disposed around said plurality of rods and being adapted to further radially expand an end portion of said heat exchanger tubes beyond the extend to which said rods expand said heat exchanger tubes; a flaring sleeve pusher slidably disposed around said plurality of rods and adjacent to said plurality of flaring sleeves, said sleeve pusher being adapted to push said plurality of sleeves into said end portion of said plurality of heat exchanger tubes under said driving force of said rod pusher; an adjustable stop positioned to mechanically limit the travel of said plurality of rods and said plurality of flaring sleeves with respect to said frame; a stop drive coupled to said adjustable stop for automatically repositioning said adjustable stop; and a control for controlling said stop drive in response to an input representing various lengths of said heat exchangers to be acted upon by said apparatus.

Claim 12

An apparatus for expanding heat exchanger tubes of various length heat exchangers having different patterns of u-bends interconnecting said heat exchanger tubes, comprising: a frame; a plurality of tube expanding rods; a universal base support fastened in fixed relationship with said frame and having a plurality of pockets for receiving said different patterns of U-bends, said base support being generally adapted to individually support any of said heat exchangers in general alignment with said tube expanding rods; a hydraulically driven rod pusher connected to said frame and said tube expanding rod, said rod pusher providing a driving force to push said rods through said heat exchanger tubes, thereby radially expanding said tubes into an interference fit against a plurality of heat transfer fins traversing said tubes, said rod pusher being further adapted to withdraw said plurality of rods from within said tubes to enable removal of any of said heat exchangers from said apparatus; a plurality of flaring sleeves slideably disposed around said plurality of rods and being adapted to further radially expand an end portion of said heat exchanger tubes beyond the extent to which said rods expand said heat exchanger tubes; a flaring sleeve pusher slideably disposed around said plurality of rods and adjacent to said plurality of flaring sleeves, said sleeve pusher being adapted to push said plurality of sleeves into said end portion of said plurality of heat exchanger tubes under said driving force of said rod pusher; an adjustable stop position to mechanically limit the travel of said plurality of rods and said plurality of flaring sleeves with respect to said frame; a stop drive coupled by way of a lead screw to said adjustable stop for automatically repositioning said stop from a first predetermined position to a second predetermined position as said rods travel through the length of said heat exchanger tubes, so that said rod guide is prevented from dropping to said second predetermined position before said rods have travelled an appreciable distance through said heat exchanger tubes, thereby preventing the weight of said rod guide from prematurely crushing any of said heat exchangers before the length of said heat exchanger tubes have been reduced as a result of the radial expansion produced by said rods; a first position feedback device associated with said adjustable stop for providing a first position feedback signal indicating the position thereof; a control for controlling said stop drive in response to said first position feedback signal and in response to an input representing the various lengths of said heat exchangers to be acted upon by said apparatus; a rod guide slideably connected to said frame and slideably disposed around said rods, said rod guide being interposed between said flaring sleeve pusher and said adjustable stop so that said flaring sleeve pusher is prevented from extending further into said tubes when said rod guide abuts both said flaring sleeve pusher and said adjustable stop; and a sleeve pusher adjustment providing a separable connection between said rod pusher and said flaring sleeve pusher for delivering said driving force of said rod pusher to said flaring sleeve pusher when said connection is made and for allowing rod movement independent of flaring sleeve pusher movement when said connection is separated, whereby a substantial length of said tubes can be expanded by said rods before said flaring sleeves further expand said end portion of said tubes, said separable connection of said sleeve pusher adjustment providing a variable spaced apart distance between said rod pusher and said flaring sleeve pusher to accommodate said various length heat exchangers, said sleeve pusher adjustment being adjusted by a motor controlled by said control in response to said input representing various lengths of said heat exchangers and in response to a second position feedback device indicating the position of said sleeve pusher adjustment.

Claim 13

An apparatus for expanding heat exchanger tubes of various length heat exchangers having different patterns of u-bends interconnecting said heat exchanger tubes, comprising: a frame; a plurality of tube expanding rods; a universal base support fastened in fixed relationship with said frame and having a plurality of pockets for receiving said different patterns of U-bends, said base support being generally adapted to individually support any of said heat exchangers in general alignment with said tube expanding rods; a hydraulically driven rod pusher connected to said frame and said tube expanding rod, said rod pusher providing a driving force to push said rods through said heat exchanger tubes, thereby radially expanding said tubes into an interference fit against a plurality of heat transfer fins traversing said tubes, said rod pusher being further adapted to withdraw said plurality of rods from within said tubes to enable removal of any of said heat exchangers from said apparatus; a plurality of flaring sleeves slideably disposed around said plurality of rods and being adapted to further radially expand an end portion of said heat exchanger tubes beyond the extent to which said rods expand said heat exchanger tubes; a flaring sleeve pusher slideably disposed around said plurality of rods and adjacent to said plurality of flaring sleeves, said sleeve pusher being adapted to push said plurality of sleeves into said end portion of said plurality of heat exchanger tubes under said driving force of said rod pusher; an adjustable stop position to mechanically limit the travel of said plurality of rods and said plurality of flaring sleeves with respect to said frame; a stop drive coupled by way of a lead screw to said adjustable stop for automatically repositioning said stop from a first predetermined position to a second predetermined position as said rods travel through the length of said heat exchanger tubes, so that said rod guide is prevented from dropping to said second predetermined position before said rods have travelled an appreciable distance through said heat exchanger tubes, thereby preventing the weight of said rod guide from prematurely crushing any of said heat exchangers before the length of said heat exchanger tubes have been reduced as a result of the radial expansion produced by said rods; a first position feedback device associated with said adjustable stop for providing a first position feedback signal indicating the position thereof; a control for controlling said stop drive in response to said first position feedback signal and in response to an input representing the various lengths of said heat exchangers to be acted upon by said apparatus; a rod guide slideably connected to said frame and slideably disposed around said rods, said rod guide being interposed between said flaring sleeve pusher and said adjustable stop so that said flaring sleeve pusher is prevented from extending further into said tubes when said rod guide abuts both said flaring sleeve pusher and said adjustable stop; and a sleeve pusher adjustment providing a separable connection between said rod pusher and said flaring sleeve pusher for delivering said driving force of said rod pusher to said flaring sleeve pusher when said connection is made and for allowing rod movement independent of flaring sleeve pusher movement when said connection is separated, whereby a substantial length of said tubes can be expanded by said rods before said flaring sleeves further expand said end portion of said tubes, said separable connection of said sleeve pusher adjustment providing a variable spaced apart distance between said rod pusher and said flaring sleeve pusher to accommodate said various length heat exchangers, said sleeve pusher adjustment being adjusted by a motor controlled by said control in response to said input representing various lengths of said heat exchangers and in response to a second position feedback device indicating the position of said sleeve pusher adjustment.

Claim 16

A method of simultaneously expanding a plurality of heat exchanger tubes traversing a plurality of fins comprising the steps of: controlling a hydraulic cylinder to force a plurality of tube expanding rods and a plurality of flaring sleeves through said plurality of heat exchanger tubes; using a motor driven lead screw to limit the travel of a rod guide slideably disposed around said tube expanding rods: and repositioning said lead screw as said tube expanding rods are being forced through said plurality of heat exchanger tubes.

Claim 17

A method of simultaneously expanding a plurality of heat exchanger tubes traversing a plurality of fins comprising the steps of: controlling a hydraulic cylinder to force a plurality of tube expanding rods and a plurality of flaring sleeves through said plurality of heat exchanger tubes; using a motor driven lead screw to limit the travel of a rod guide slideably disposed around said tube expanding rods: and repositioning said lead screw as said tube expanding rods are being forced through said plurality of heat exchanger tubes.