US2866429A

US2866429A - Semi-automatic apparatus for expanding a pressure welded passageway panel

Info

Publication number: US2866429A
Application number: US552185A
Authority: US
Inventors: Paul R Staples
Original assignee: Reynolds Metals Co
Current assignee: Reynolds Metals Co
Priority date: 1955-12-09
Filing date: 1955-12-09
Publication date: 1958-12-30
Anticipated expiration: 1975-12-30

Description

A P. R. STAPLES SEMI-AUTOMATIC APPARATUS FOR EXPANDING A PRESSURE WELDED PASSAGEWAY PANEL Filed Dec. 9, 1955 Dec. 30, 1958 3 3 \3 m 1 1 L I T i 1 ElllllL r r IN VEN TOR. PAUL R. STAPLES BY E ATTORNEY panded into the holding chamber.

United SEMI-AUTOMATIC APPARATUS FOR EXPANDING A PRESSURE WELDED PASSAGEWAY PANEL 'Paul R. Staples, Louisville, Ky., assignorto Reynoids Metals Company, Louisville, Ky., a corporation of Delaware This invention relates to a semi-automatic apparatus for expanding the unbonded portions of a pressure welded passageway panel.

It has been proposed to expand a pressure welded or roll bonded passageway panel on one outer face only by applying a holding liquid under pressure to that one outer face so to hold its other outer face in fiat face-to-face contact with the die and then introducing an expansion liquid under relatively higher pressure into the panel. The holding pressure on the one outer face of the panel holds the other outer face in relatively unyielding engagement with the die and thus tends to prevent the said other face from expanding while permitting the said one face to expand into the holding liquid.

Variations occur in the expanding operation when it is controlled manually. Such variations result in expanded passageways of varying volumetric capacity. This is objectionable particularly when the expanded panel is to be used as an evaporator in a refrigerator ofthe type wherein a capillary tube is employed to provide a pressure differential. Here the relationship, between the volume of the refrigerant charge and that of the system, is somewhat critical.

It is an object of the present invention to provide a control apparatus for developing and applying pressures of the desired magnitude and in the desired sequence for producing one side expansion of the unbonded passageway forming'portions of the panel and for automatically releasing the pressures at the desired rates and times.

Another object is the provision of an apparatus for producing a uniform degree of expansion throughout the panel so as to minimize volumetric variations in the expanded passageways due to variations in the overall thickness of the panel.

'A conventional apparatus, for expanding the unbonded portions of a pressure welded passageway panel on one side of the panel, comprises: a pair of dies relatively movable between open and closed positions, said dies being adapted to receive a panel in the die open position and to limit the outward expansion thereof in the die closed position, one of the dies having a holding chamber over which said one side of the panel is placed; a hydraulic jack for moving one of said dies; and three conduits including a die conduit connected to the jack for transmitting die closing liquid thereto, a holding conduit connecting to the holding chamber for transmitting panel holding liquid thereto and a panel expansion conduit adapted for connection to a panel for transmitting panel expanding liquid to its unbonded portions; and manually operable means for supplying liquid under pressure to each of these conduits. In the closed position of the dies, the holding chamber is covered by the one adjacent face of a panel interposed between dies. This holding chamber is large enough lengthwise and widthwise to embrace said one face over the expansion area containing the unbonded portions of the panel which are subsequently to be ex- That chamber is also dimensioned depthwise to limit subsequent expansion to 2,866,429 Patented Dec. 30, 1958 ply of holding liquid under pressure, of the holding liquid to institute the supply of expansion liquid under pressure and of the expansion liquid to release all pressures. In the preferred embodiment, the control apparatus comprises: means operating, when manually actuated, to supply die closing liquid under pressure to the die conduit; means operating, when automatically actuated in response to a predetermined pressure in a die conduit, to supply panel holding liquid under pressure to said holding conduit; means operating, when automatically actuated in response to a predetermined pressure in the holding conduit, to supply panel expanding liquid under pressure to said expansion conduit; and means operating, when automatically actuated in response to a predetermined pressure in the expansion conduit, to release the pressure in all conduits.

An embodiment of the invention is illustrated in the drawings, wherein:

Figure l is a partly broken plan view of an unexpanded roll bonded passageway panel;

Figure 2 is a section taken along line HIl of Figure l; and

Figure 3 is a more or less schematic or diagrammatic view of the die and control apparatuses for practicing the present invention.

The present invention can be readily explained in connection with the drawing which illustrates: a panel; a die apparatus; and a control apparatus.

PANEL DIE APPARATUS The die apparatus comprises: an upper stationary die member 5 having a rigid fiat die face 6; a lower movable die member 7' having a die face 8 which is recessed at 9 to provide a holding chamber 9 and recessed at 10 to provide an entrance to that holding chamber; an 0 sealing ring 11 encircling chamber 9; and a conventional hydraulic jack 12 composed of a piston, also designated 12, and a cylinder 13 having a liquid pressure or jack chamber 14.

It will be understood that panel 1 is placed between the upper and lower die members 5 and 7 with its bottorn face resting on the O sealing ring 11. The dies are closed to effect a very tight seal, between the panel 1 and the sealing ring 11, which completes the enclosure of the holding chamber 9. Now a holding pressure may be introduced into the recess or chamber 9 while an expansion pressure is introduced into the panel I. The control apparatus operates'to eflFect the closing of the dies, the application of the holding and expansion pressures and the final release of all such pressures.

3 CONTROL APPARATUS The control apparatus comprises: die closing means; panel holding pressure applying means; panel expansion pressure applying means; and pressure releasing means.

Die closing means The die closing means includes a reservoir 16, from which a continuously operating pump 17 draws liquid and pumps it into conduit 18 which is not only connected to the hydraulic jack chamber 14 but also cnnected back to reservoir 16 through a normally open solenoid valve 19. So long as this valve 19 remains open, it prevents the pump 17 from building up a die operating pressure in the jack chamber 14.

The normally open valve 19 is controlled by :1 normally de-energized solenoid coil 20. The energization of solenoid coil 20 is controlled by a normally open manually .closable starting circuit which extends from one side 22 of the supply line through a push button 23, relay coil 24 to the other side 25 of the power supply line. The energization of relay coil 24 closes both ofits normally open switches 26 and.27, switch 26 operating to close the solenoid coil 20 circuit extending from line 22 through switch 26, coil 20 to line 25 and switch 27 operating to establish a shunt circuit around push button 23 so as to maintain coil 24 energized when push button 23 is released.

With the energization of solenoid coil 20, valve 19 closes the hydraulic return circuit from conduit 18 back to the reservoir 16 and thus enables pump 17 to build up a pressure in the hydraulic jack chamber 14 sutficient to move the dies to the closed position. When the dies reach the closed position, the pump 17 will increase the hydraulic pressure on the dies to a predetermined value, which is determined by the setting of a normally closed relief valve 28 connecting the conduit 18 back to the reservoir 16. The die holding pressure, at which the dies are held closed, or the strength of other means by which they may be held closed, is large enough to overcome the combined effects of the panel holding pressure, which is to be introduced into the holding chamber 9 of the lower die, and expansion pressure, which is to be introduced into the pressure welded panel 1 itself.

The closure of the dies is usedto initiate the operation of the means for applying the holding pressure.

Panel holding pressure applying means Liquid, for panel holding pressure purposes, is supplied through water supply 30, check valve 31, conduit 32, normally closed solenoid valve 33 and conduit 34 to the holding chamber 9. T 0 open the normally closed panel holding pressure line 34, the coil for solenoid valve 33 must be energized. The means to energize it is made responsive to the closure of the dies by connecting sole noid coil 55 to the power supply line through a normally open switch 37 which is responsive to the die holding pressure in the jack chamber 14 and the conduitlS and which is designed to close when the pressure, developed in circuit 18, rises to a value suflicient to prevent the dies from being forced apart during the expansion operation by the maximum counteracting load imposed on the piston as a result of the expansion operation.

To provide a panel holding fluid, under the requisite value of holding pressure, a compressed air supply .40 is connected, through solenoid valve 41, to the low pressure side of a booster accumulator 42, the high pressure side of which is connected to the holding liquid conduit 32. The booster accumulator 42 is of conventional structure utilizing a low air pressure acting on the large area of a differential piston to apply, to the liquid in the hydraulic conduit 32, a large total pressure through the smaller differential area ofthat same piston. The booster accumulator 42 .is made to operate, in response to the closure of the dies, by connecting its solenoid coil 43 and the solenoid coil 35 for the valve 33, in parallel between line 22 on the one side and switch 37 on the other.

Now it will be understood that, when the die holding pressure in conduit 18 reaches its predetermined die holding value, it becomes effective to close pressure switch 37, which is .in series with each of the parallel solenoid coils 35 and .43. As a result, the panel holding pressure line 34, leading to the holding chamber 9, is opened and the booster accumulator 42 operated to place the liquid line 34 and chamber 9 under a panel holding pres sure of a predetermined order.

The rise of the panel holding pressure, toward or to a predetermined value, is used to imitate the operation of the means for applying the expansion pressure.

Panel expansion pressure applying means The panel expansion pressure liquid system includes water supply 30 leading through check valve 31 and conduit 47 to a quickly detachable coupling 48 for the fluid pressure connector 4. The coupling 48, for connector 4, is of the conventional quick-operating type having a valve, which, when the coupling is connected, provides an open passageway between expansion liquid conduit 47 and the interior of the fluid connector 4, and, when the coupling is disconnected, closes the end of the conduit 47 and thus prevents the leakage of water.

The panel expansion system is made responsive, to a predetermined value of panel holding pressure in the conduit 34 and holding chamber 9, by connecting the compressed air supply 40 through solenoid valve 51 to a booster accumulator 52 and by connecting the coil 53 of the solenoid valve 51 to power through a normally open pressure switch 54 which is responsive to the panel holding pressure in conduit 34. The circuit for solenoid coil 53 extends from one side 22 of the line through solenoid coil 53, pressure switch 54 and pressure switch 37 to the other side of the line 25. As a consequence, as soon as coil 53 is energized, the booster accumulator 52 operates to impose an expansion pressure in the hydraulic expansion circuit containing conduit 47 causing the panell to be expanded as the expansion pressure in its passageway system rises to a predetermined value.

The top value of expansion pressure, which is predetermined, is used to initiate the operation of the means for releasing all pressures.

Pressure release means When the expansion pressure reaches a predetermined value, it is desirable to release the pressure and shut down the entire apparatus. Accordingly, a normally closed pressure switch 60, which is responsive to the expansion pressure, is arranged to open at the predetermined top expansion pressure. This switch 60 is serially connected with relay switch 27 to form the shunt circuit, which extends around push button switch 23 and which maintains the relay-energizing circuit of relay coil 24 closed when switch 23 opens. Consequently, when switch 60 is opened, it de-energizes relay coil 24 causing relay switches 26 and 27 to open.

The opening of relay switch 26 de-energizes the solenoid coil 20 to open valve 19. This releases the pressure in the hydraulic die-holding circuit, allowing the dies 5 and 7 to open. The release of the die-holding pressure, opens pressure switch 37, which, in turn, opens two electric circuits, namely: the electric circuit of

solenoid coils

35 and 43 respectively, controlling the fiow of panel holding fluid in the hydraulic holding circuit through valve 33 and the application of pressure thereto through valve 41; and the electric circuit of solenoid coil 55, controlling the application of pressure to the panel expanding fiuid in the hydraulic expansion circuit through valve 51. As a result, the panel holding and expanding pressures are immediately released.

The opening of relay switch 27 creates a second opening in the shunt circuit around push button 23, and thus prevents relay coil 24 from immediately becoming reenergized by the re-closure of pressure switch 60, which re-closure occurs with the release of expansion pressure in line 47.

The de-energization of the relay coil 24 and the opening of its switches 26 and 27 thus conditions the apparatus for the next series of operations involving the removal of the expanded panel, its replacement by the next unexpanded panel and the institution of the automatic operations which follow the closure of the manually 0perated push button 23.

Operating conditions and variations The fluid pressure valves used will, of course, vary depending on the composition of the panel. With a conventional aluminum panel, a differential between the holding and expansion pressures of about 2,000 to 3,000 p. s. i. is recommended. With a differential of 2,400 p. s. i., a holding pressure of 600 p. s. i. and an expansion pressure of 3,000 p. s. i. may give good result but progressively higher holding pressures, Within operating limits, should give progressively better results. Necessarily, whatever the holding and expansion pressures are, the pressure which holds the dies closed must be sufficient to resist the die separating forces created by the holding and expansion pressures.

The present invention may be applied to a die apparatus for expanding both sides by eliminating the holding chamber, holding conduit and the holding'liquid pressure supply means and by making the expansion liquid pressure supply means automatically responsive to the die closing pressure. The latter can be accomplished swiftly by eliminating pressure switch 54 and permanently closing the contacts of switch 54.

I claim as my invention:

An apparatus for expanding certain unbonded portions of a pressure welded passageway panel on one side or face of the panel comprising: a pair of dies relatively movable between open and closed positions, said dies being adapted to receive a panel in the open position and to limit the outward expansion thereof in the closed position, one of said dies having a holding chamber which, in the closed position of the dies, is covered by the one adjacent face of an interposed panel, said holding chamber being large enough lengthwise and widthwise to embrace said one face over the expansion area containing said unbonded portions which are subsequently to be expanded into the holding chamber and being dimensioned depthwise to limit the expansion to a predetermined extent whereby variations between the unbonded portions of the panel faces may be accommodated, the other die having flush face-to-face engagement with the other face of said panel over an area corresponding to said expansion area; a hydraulic jack for moving one of said dies; a die conduit connected to the jack for transmitting die closing liqud thereto; a holding conduit connected to the holding chamber for transmitting panel holding liquid thereto; an expansion conduit adapted for connection to a panel for transmitting panel expanding liquid to its unbonded portions; means operating, when manually actuated, to supply die closing liquid under pressure to the die conduit; means operating, when automatically actuated in response to a predetermined dieclosing liquid pressure, to supply panel holding liquid to said ho-ldingchamber through said holding conduit under a predetermined holding pressure exerted against said one face for the purpose of maintaining said corresponding area of said other face in flush face-to-face engagement with said other die during subsequent expansion; means operating, when automatically actuated in response to a predetermined panel-holding liquid pressure, to supply panel expanding liquid to the interior of said panel through said expansion conduit under a predetermined panel-expanding liquid pressure suflicient to expand said unbonded portions on said one face into said holding chamber against said holding pressure therein but insufficient to expand the corresponding unbonded portions on said other panel face while such portions are held in said flush engagement with said other die by said holding pressure; and means operating, when automatically actuated in response to a predetermined panel-expanding liquid pressure, to release said die-closing, panelholding and panel-expanding pressures.

References Cited in the file of this patent UNITED STATES PATENTS 1,891,121 Thoreson Dec. 13, 1932 2,241,807 Cotner May 13, 1941 2,317,869 Walton Apr. 27, 1943 2,398,227 Hubbert Apr. 9, 1946 2,582,358 Schoellerman Jan. 15, 1952 2,625,195 Tremblay Jan. 13, 1953 2,690,002 Grenell Sept. 28, 1954 2,713,314 Leuthesser et a1. July 19, 1955 2,766,711 Dever et a1. Oct. 16, 1956