Information
-
Patent Grant
-
6513232
-
Patent Number
6,513,232
-
Date Filed
Friday, November 30, 200122 years ago
-
Date Issued
Tuesday, February 4, 200321 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Vidovich; Gregory M.
- Nguyen; T.
Agents
- Modiano; Guido
- Josif; Albert
- O'Byrne; Daniel J.
-
CPC
-
US Classifications
Field of Search
US
- 029 727
- 029 726
- 029 818
- 029 723
- 029 890044
- 029 890046
- 029 890053
- 029 809
- 029 523
- 029 715
- 029 890047
- 072 37006
- 072 37007
- 072 479
- 269 43
-
International Classifications
-
Abstract
A vertical pipe expander to be used to expand the pipes assembled with fins of finned heat exchangers comprises, on a supporting frame, supports for rods of pipe expanding cones, performing vertical translational motion and arranged above a seat for a heat exchanger to be subjected to pipe expansion. At least one cone supporting rod magazine is further provided that is arranged vertically with the cones directed downward, for arrangement, during machine setup, at the seat, the supports for the rods being constituted by a rod engaging and supporting device. The rod engagement and support device is associated with a device for selecting the rods of the magazine to be engaged or released.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a vertical pipe expander.
Machines of this type are used to expand pipes assembled with the fins of finned heat exchangers.
Heat exchangers, after the initial assembly step in which individual fins are fitted on pipes so as to form a finned pack, require this additional technological operation in order to obtain stable contact between the fins and the very pipes.
This contact allows optimum heat transmission between the fluid that flows inside the pipes, and the fluid, normally air, that strikes the fins.
A vertical pipe expander is conceptually a hydraulic press with various electromechanical servomechanisms, in which a finned heat exchanger is arranged vertically in a downward region on a supporting frame.
In the region above the supporting frame there are rods provided at their tips with pipe expanding cones; such rods are associated with a corresponding support for vertical movement and are arranged vertically.
The rods that support the pipe expanding cones are actuated simultaneously so as to advance downward, entering the pipes of the heat exchanger so as to widen their diameter by means of the cones.
However, pipe expanders of the known type are not free from drawbacks.
They are in fact particularly inflexible from the point of view of operation.
Heat exchangers can be manufactured with pipes having different thicknesses and diameters.
This entails the use of cones that are specific for each pipe thickness, therefore entailing the need to replace the rods when the type of exchanger varies.
Furthermore, since the arrangement of the pipes varies for each exchanger type, it is necessary to provide a device for selecting the cone supporting rods that must perform the expansion whenever it is necessary to an exchanger whose configuration is different from that of a preceding one.
The rod replacement operation is currently completely manual; furthermore, since the cones have size differences that are difficult to distinguish with the naked eye, the machine can often be subjected to an incorrect setting.
Machine downtimes are therefore particularly high, since the setting operation also is completely manual.
SUMMARY OF THE INVENTION
The aim of the present invention is to solve or substantially reduce the problems of known types of vertical pipe expander.
Within this aim, an important object is to provide a pipe expander that is operatively flexible and versatile.
Another object is to provide a machine in which cone supporting rods of different sizes can be changed completely automatically.
Another object is to provide a pipe expander with automatic selection of the rods to be used in the technological operation.
Another object is to provide a pipe expander that requires very short machine downtimes and setup times.
Another object is to provide a machine that is safe for the user and ergonomic.
This aim and these and other objects that will become better apparent hereinafter are achieved by a pipe expander of the vertically elongated type that comprises, on a supporting frame, supporting means for rods that support pipe expanding cones, which can perform a vertical translational motion and are arranged above a seat for a heat exchanger to be subjected to pipe expansion, characterized in that it comprises at least one cone supporting rod magazine that is arranged vertically so that the cones are directed downwardly, to be arranged, during a machine setup step, at said seat, said supporting means for cone supporting rods being constituted by a device for engaging and supporting rods at their rear end portion, said rod engagement and support device being associated with a device for selecting the rods of the magazine to be engaged or released, with said magazine arranged in said seat.
BRIEF DESCRIPTION OF THE DRAWINGS
Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment thereof, illustrated only by way of non-limitative example in the accompanying drawings, wherein:
FIG. 1
is a front view of a pipe expander according to the invention;
FIG. 2
is a partially sectional schematic side view of a portion of the pipe expander of the preceding figure;
FIGS. 3
,
4
and
5
are schematic front views of the pipe expander in three different steps of operation;
FIGS. 6 and 7
are schematic plan views of the pipe expander in two different steps of operation;
FIG. 8
is a plan view of a component of a pipe expander according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
With reference to the figures, a pipe expander according to the invention is generally designated by the reference numeral
10
.
The pipe expander
10
is of the vertically elongated type and comprises, on a lattice-like frame
11
that comprises a footing
44
, supporting means
12
for rods
13
provided, at their front end, with cones
14
for expanding the pipes of a heat exchanger.
In
FIGS. 2
to
7
, the pipe expander
10
has been illustrated schematically, for the sake of simplicity, as if it had just two rods
13
.
The supporting means
12
is arranged on the frame
11
at its upper portion
15
.
At the upper portion
15
, the supporting means
12
performs a vertical translational motion on corresponding rectilinear guides
16
that are not shown in
FIGS. 2
to
7
for the sake of simplicity.
The lower portion
17
of the frame
11
forms a seat
18
for a heat exchanger, arranged in axial alignment with the rods
13
associated with the supporting means
12
, to be subjected to the technological expansion process.
The supporting means
12
is constituted by a device for engaging and supporting the rear end portion
19
of the rods
13
, which is described in greater detail hereinafter.
The engagement and support device comprises a substantially plate-like slider
20
that is arranged horizontally and so that it can slide with a transverse rectilinear motion on the lower portion
21
a
of a supporting plate
21
, which in turn can perform a vertical translational motion because it is associated with the rectilinear guides
16
.
The slider
20
is provided with a plurality of slotted holes
22
that are aligned in the direction of the translational motion and are equal in number to the rods
13
to be supported.
Each slotted hole
22
is constituted by two portions: a first portion
23
, whose transverse dimension is greater than the diameter of the rods
13
, and a second portion
24
, whose transverse dimension is smaller than the diameter of the rods
13
and greater than the diameter of a circumferential groove
25
provided in the rear end portion
19
of each rod
13
.
The groove
25
has an axial dimension that is greater than the thickness of the slider
20
, so that the second portion
24
of the hole
22
can engage thereon.
The supporting plate
21
is provided with holes
26
that correspond to the rods
13
and allow said rods to enter and pass through the slider
20
and through the slotted holes
22
.
Multiple guiding plates
27
for the rods
13
associated with said supporting means
12
and provided with through holes
45
for said rods
13
are arranged below the supporting plate
21
so that they can slide on the rectilinear guides
16
.
Said guiding plates
27
and the supporting plate
21
are arranged so as to be spaced when inactive.
In practice, the supporting means
12
, as described in greater detail hereinafter, picks up the rods
13
from a magazine
28
.
The magazine
28
comprises a box-like body
29
that is provided with tubular seats
30
for rods
13
arranged vertically, with cones
14
arranged downwardly and with at least the rear end portion
19
arranged externally.
The magazine
28
further comprises a perforated guiding plate
31
for the rear end portions
19
of the rods
13
arranged outside the box-like body
29
.
The perforated plate
31
can perform a vertical translational motion and is associated with pneumatic cylinders
32
that act as elastic spring means that push upward.
In particular, the perforated guiding plate
31
, when the pneumatic cylinders
32
are inactive, is arranged at a lower level than the grooves
25
of the rods
13
.
The pipe expander
10
further comprises a device for selecting the rods
13
to be engaged by means of the slider
20
, which is described in greater detail hereinafter.
The device for selecting the rods
13
to be engaged is constituted by a plurality of pushers
33
, one for each rod
13
, which are arranged above the slider
20
in corresponding seats
34
provided in the upper portion
21
b
of the supporting plate
21
.
The pushers
33
are pneumatic cylinders, whose stems
35
are arranged coaxially to the holes
26
of the supporting plate
21
.
Said stems
35
pass through the slotted holes
22
of the slider
20
without interfering with it even during its transverse translational motion.
The stems
35
then pass through the slider
20
through the slotted holes
22
, partially entering the holes
26
of the supporting plate
21
.
Each pusher
33
acts in opposition to a corresponding elastic element
36
arranged on the bottom of the magazine
28
for supporting a corresponding rod
13
.
The elastic elements
36
are constituted by pistons
37
, on which the rods
13
rest with the cones
14
; said pistons can slide on corresponding vertical guides
38
and are associated with springs
39
that act by pushing upward.
In practice, the pistons
37
form a supporting surface that locally yields elastically for each rod
13
.
The supporting plate
21
further supports, on two mutually opposite sides, two mutually opposite hydraulic actuators
40
for the transverse translational motion of the slider
20
.
The guiding plate
27
a
arranged further downward has a numerically controlled position and is designed to pre-measure the finned pack of an exchanger to be subjected to the technological process of expansion.
Said plate
27
a
detachably supports spacer elements
41
for said finned pack.
Said spacer elements
41
are constituted by tubular segments that are arranged coaxially to the rods
13
and are fixed at their front end, by means of elastic snap rings, to said pre-measuring plate
27
a.
Advantageously, flaring cups
42
for the end portion of the pipes of a finned exchanger can be fitted on the rods
13
.
The cups
42
are fitted on the rear end portion
19
of the rods
13
and rest in an upward region on the perforated plate
31
of the magazine
28
.
The cups
42
can slide on the rods
13
and encounter a downward limit for vertical translational motion at the cones
14
.
The cups
42
instead encounter an upper limit for vertical translational motion at a guiding plate
27
b
that is arranged above the guiding and pre-measuring plate
27
a.
The magazine
28
is arranged on a carriage
43
that can perform a vertical and transverse translational motion and is in turn arranged at the seat
18
.
The movable carriage
43
can slide on the footing
44
of the frame
11
and supports the magazine
28
during a machine setup step, entering the space occupied by the seat
18
.
As regards operation, during the machine setup step a rod magazine
28
is arranged at the movable carriage
43
.
At this point the structure
10
is located at its upper stroke limit, as shown in
FIG. 3
, with the supporting plate
21
arranged at the maximum height and the guiding plates
27
in a spaced configuration.
The movable carriage
43
is actuated automatically so as to be arranged at the seat
18
, so that the rods
13
contained in the magazine
28
are arranged coaxially to the holes of the guiding plates
27
and to the pushers
33
of the supporting plate
21
.
At this point the vertical upward motion of the movable carriage
43
and the simultaneous downward motion of the supporting plate
21
are actuated.
As a consequence of the downward motion of the supporting plate
21
, the guiding plates
27
also perform a downward transational motion, simultaneously reducing their relative distance.
In particular, the spacers
41
of the plate
27
b
rest on the perforated plate
31
of the magazine
28
, pushing it downward in contrast with the pneumatic cylinders
32
.
At the lower stroke limit of the structure
10
, as shown in
FIG. 4
, the perforated plate
31
of the magazine
28
is pushed by the spacer elements
41
at its minimum height position and the guiding plates
27
are arranged closely together, with the supporting plate
21
also arranged at the minimum height.
In this configuration, the rods
13
pass through the spacers
41
and the holes of the guiding plate
27
and lie, with their rear end portion
19
, inside the supporting plate
21
.
In particular, the stems
35
of the pushers
33
pass through the slotted holes
22
of the slider
20
, pushing the rods
13
beyond the space occupied by the slider
20
in contrast with the elastic elements
36
on which said rods
13
rest.
The slider
20
is arranged, in this case, so that the portions
23
of the slotted holes
22
are coaxial to the rods
13
.
At this point, according to a preset program that depends on the type of heat exchanger to be processed subsequently, the selected pushers
33
are actuated, drawing them upward and allowing the elastic elements
36
to push the corresponding rods
13
upward, simultaneously allowing their rear end portion
19
to enter the space occupied by the slider
20
(see again FIG.
4
).
At this point, the hydraulic actuators
40
actuate the translational motion of the slider
20
so that the portions
24
of the slotted holes
22
engage the grooves
25
of the rods
13
that pass through said slotted holes
22
, engaging them stably.
Once this operation has ended, the expander
10
is actuated so as to be arranged again at its upper stroke limit.
The supporting plate
21
is drawn upward and the magazine
28
, supported by the movable carriage
43
, is returned downward and moved out of the space occupied by the seat
18
.
In this manner, the rods
13
that have not been engaged remain inside the magazine
28
, while the engaged ones are supported by the supporting plate
21
.
At the upper stroke limit, the guiding plates
27
again arrange themselves so that they are spaced and the cones
14
of the rods
13
lie above the lower portion
17
of the supporting frame
11
.
The machine is now set up and it is therefore possible to position a heat exchanger at the seat
18
, aligned with the rods
13
supported by the plate
21
.
The lowering of the supporting plate
21
is then actuated, accordingly allowing the cones
14
to engage in the pipes of the heat exchanger, increasing their diameter and stably ensuring their assembly with the fins.
If cups
42
are also arranged slidingly in the rods
13
, when the rods
13
are almost at the end of their stroke, at the bottom stroke limit of the machine, the plate
27
b
pushes said cups
42
so as to flare the end portion of the pipes of the heat exchanger.
It is evident that the rods
13
are subjected to a rather intense tip stress (the machine can in fact generate up to 60 t in the press), which would entail inflection deformations.
The guiding plates
27
therefore have the function of keeping said rods
13
in a straight vertical configuration.
As mentioned, in
FIGS. 2
to
7
the pipe expander
10
has been shown schematically as if it had only two rods
13
.
Actually, the number of rods
13
is much higher.
FIG. 8
, for example, is a plan view of a slider
20
that is normally used and is provided with a number of slotted holes
22
equal to the maximum number of rods
13
that can be supported by the plate
21
.
The operation of the machine can be automated completely and is managed by a computerized system included in the control panel.
In practice, given the arrangement and number of pipes of a heat exchanger to be subjected to the technological process of expansion, a corresponding rod selection program is set up.
Moreover, the pipe expander can be provided with a plurality of interchangeable rod magazines provided with cones of different diameters, depending on the thickness of the pipes of the heat exchangers.
Furthermore, it can have a single machining station, of the fixed type or with an inverter or of the turntable type with two or more machining stations.
Therefore, depending on the size of the exchanger, and more specifically on the thickness, number and arrangement of the pipes, the pipe expander
10
, given programs stored beforehand or entered during setup, is capable of using the rod magazine suitable for the pipe thickness and of selecting the number of rods to be taken from said magazine.
In practice it has been found that the present invention has achieved the intended aim and objects.
A pipe expander has in fact been provided by means of which the operation for replacing and selecting the rods for expanding the pipes of a heat exchanger has been automated completely.
Accordingly, there is a drastic reduction in machine downtimes and in setup times.
Moreover, the machine is more flexible and versatile.
The problem of accidental swapping of rods provided with cones of different sizes because they are difficult to recognize with the naked eye is solved.
Moreover, the pipe expander is remarkably safer, since operators are now located outside the footprint of the machine, which is controlled fully automatically.
The present invention is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.
All the technical details may be replaced with other technically equivalent elements.
The materials, so long as they are compatible with the contingent use, as well as the dimensions, may be any according to requirements.
The disclosures in Italian Patent Application No. PD2000A000272 from which this application claims priority are incorporated herein by reference.
Claims
- 1. A pipe expander of a vertically elongated type for expanding pipes of a heat exchanger, comprising: a supporting frame; cone supporting rods, supported at said frame; supporting means for rods; pipe expanding cones, supported at front end portions of said cone supporting rods to perform a vertical translational motion; a seat provided at said frame for accommodating a heat exchanger to be subjected to pipe expansion, said expanding cones being arranged above said seat; at least one cone supporting rod magazine arranged on a movable carriage; said magazine being arranged vertically with the expanding cones directed downwardly, so as to be arranged, during machine setup, at said seat, said supporting means for cone supporting rods being constituted by a device for engaging and supporting rods at a rear end portions of supporting rods and a selecting device associated with said device for engaging and supporting rods for automatically engaging or releasing selecting rods of the magazine, with said magazine arranged in said seat.
- 2. The pipe expander of claim 1, wherein each one of said rods has a circumferential groove formed in the rear end portion thereof, and wherein said device for engaging and supporting rods comprises a substantially plate-like slider that is arranged horizontally so as to perform translational motion in vertical and horizontal directions, said slider being provided with a plurality of slotted holes arranged in one of said horizontal directions of motion, in a number being at least equal to a number of rods of said magazine, each slotted hole comprising at least one first portion with a transverse dimension which is greater than a diameter of the rods and at least one second portion with a transverse dimension which is smaller than the diameter of the rods and greater than a diameter of a circumferential groove having an axial dimension that is greater than a thickness of said slider.
- 3. The pipe expander of claim 2, further comprising: a supporting plate provided with a seat formed thereon to correspond to said slider; and rectilinear guides arranged on said frame, said horizontal motion of said slider occurring on said corresponding seat formed in said supporting plate, and said vertical motion being provided by the translational motion of said supporting plate, which is slidable on said rectilinear guides, said supporting plate being further provided with access holes for access, within a space occupied by said slider, of the rear end portions of said rods.
- 4. The pipe expander of claim 3, wherein said device for engaging and supporting rods comprises a plurality of rod guiding plates that are spaced in an idle configuration, lie below said supporting plate, are slidable on said rectilinear guides, and are provided with through guiding holes for said rods, said through guiding holes being coaxial to said access holes of the supporting plate.
- 5. The pipe expander of claim 4, wherein said magazine comprises a box-like body that is provided with tubular seats for said rods, with said rods being arranged vertically with the pipe expanding cones arranged downward and with at least the rear end portions thereof arranged outside said box-like body.
- 6. The pipe expander of claim 5, characterized in that said rods have each a circumferential groove formed in the rear end portion thereof, said magazine comprising: a perforated plate that is actuatable to perform a vertical translational motion for guiding the rear end portions of the rods arranged outside said box-like body, and elastic means for pushing upward the perforated plate which is arranged, in an idle configuration, below said circumferential grooves.
- 7. The pipe expander of claim 6, wherein said elastic means are pneumatic cylinders.
- 8. The pipe expander of claim 2, comprising elastic means arranged on a bottom part of said magazine on which said rods rest, said selecting device being constituted by a plurality of pushers, one for each slotted hole of said slider, said pushers being arranged so as to act, during machine setup, on said rods in contrast with said elastic elements, said pushers retaining, on command, selected rods outside a space occupied by said slider.
- 9. The pipe expander of claim 8, wherein said pushers are constituted by pneumatic actuators arranged above said slider coaxially to the rods, said pneumatic actuators having stems acting by pushing on the rear end portion of said rods, said stems passing through the slotted holes of said slider and having such dimensions as to not interfere with the horizontal translational motion thereof.
- 10. The pipe expander of claim 8, further comprising: vertical guides and pushing springs, said elastic elements arranged on the bottom part of the magazine being constituted by pistons that are slidable on corresponding ones of said vertical guides and are associated with said pushing springs that act by pushing upward, each rod resting, with a cone thereof, on a corresponding one of said pistons, said pistons forming a supporting surface that locally yields elastically for each rod.
- 11. The pipe expander of claim 3, further comprising two hydraulic actuators supported laterally by said supporting plate, said hydraulic actuators being arranged mutually opposite for enabling movement of said rod engagement slider.
- 12. The pipe expander of claim 6, wherein a lower one of said rod guiding plates is arranged in a numerically controlled position and constitutes a pre-measurer for a finned pack of a heat exchanger to be subjected to pipe expansion.
- 13. The pipe expander of claim 12, comprising flaring cups for operating at end portions of pipes of a finned exchanger, said cups being fitted on said rods, above said perforated plate of said magazine, said cups being slidable on the rods, until encountering a lower stroke limiter constituted by the pipe expanding cones and an upper flared pusher stroke limiter, constituted by the guiding plate of the device for engaging and supporting rods that is arranged above said plate for pre-measuring a finned pack.
Priority Claims (1)
Number |
Date |
Country |
Kind |
PD00A0272 |
Dec 2000 |
IT |
|
US Referenced Citations (10)