U.S. patent application number 12/350455 was filed with the patent office on 2010-07-08 for molding apparatus and method with heat recovery.
Invention is credited to Stephen B. MAGUIRE.
Application Number | 20100170659 12/350455 |
Document ID | / |
Family ID | 42310961 |
Filed Date | 2010-07-08 |
United States Patent
Application |
20100170659 |
Kind Code |
A1 |
MAGUIRE; Stephen B. |
July 8, 2010 |
MOLDING APPARATUS AND METHOD WITH HEAT RECOVERY
Abstract
Apparatus and method for recapturing and reusing heat provided
in the course of fabricating a molded product.
Inventors: |
MAGUIRE; Stephen B.; (Glenn
Mills, PA) |
Correspondence
Address: |
CHARLES N. QUINN;FOX ROTHSCHILD LLP
2000 MARKET STREET, 10TH FLOOR
PHILADELPHIA
PA
19103
US
|
Family ID: |
42310961 |
Appl. No.: |
12/350455 |
Filed: |
January 8, 2009 |
Current U.S.
Class: |
165/104.19 |
Current CPC
Class: |
B29C 33/04 20130101;
F28D 7/106 20130101; B29C 48/78 20190201; B29C 45/72 20130101; B29B
13/021 20130101; Y02P 70/26 20151101; Y02P 70/10 20151101; B29B
13/02 20130101; Y02P 70/263 20151101; B29C 43/52 20130101; B29C
49/4823 20130101; B29C 51/42 20130101; B29C 2045/7292 20130101 |
Class at
Publication: |
165/104.19 |
International
Class: |
F28D 15/00 20060101
F28D015/00 |
Claims
1. Apparatus for pre-heating moldable materials prior to molding
using heat recovered from the molding process comprising: a)
molding apparatus having an interior surface defining a molding
chamber, and at least one fluid flow channel passing through the
apparatus and being thermally coupled to the molding chamber; b) a
heat exchanger; c) said fluid flow channel communicating with the
molding apparatus and the heat exchanger for fluid circulation
between the molding apparatus and the heat exchange apparatus to
transfer heat from a molded product and parts of the molding
apparatus adjacent thereto within the molding apparatus to the heat
exchanger; and d) a container housing raw materials for molding
into a molded product the container interior being in fluid
communication with the heat exchanger such that a second fluid
transfers heat from the heat exchanger to the container raw
material contents so as to heat the raw materials prior to
molding.
2. Apparatus of claim 1 wherein the molding apparatus and the heat
exchanger are in fluid communication by way of one or more fluid
channels.
3. Apparatus of claim 2 wherein the fluid channels form a
continuous loop between the molding apparatus and the heat
exchanger.
4. Apparatus of claim 1 wherein the fluid is transferred from the
molding apparatus to the heat exchanger by convective currents.
5. Apparatus of claim 1 wherein the molding apparatus is selected
from the group consisting of a stretch blow-molding apparatus,
injection molding apparatus, compression molding apparatus,
thermomolding apparatus, thermoforming apparatus, vacuum forming
apparatus, transfer molding apparatus, extrusion molding apparatus,
and rotational molding apparatus.
6. Apparatus of claim 1 where is the first fluid is selected from
the group consisting of water, air, thermal oil, refrigerant, and
combinations thereof.
7. Apparatus of claim 1 wherein the first fluid is circulated
between the molding apparatus and the heat exchanger using a
turbulent flow.
8. Apparatus of claim 1 wherein the heat exchanger comprises a
shell-tube heat exchanger.
9. Apparatus of claim 8 wherein the shell-tube heat exchanger is
selected from the group consisting of parallel-flow heat
exchangers, counterflow heat exchangers, cross-flow heat
exchangers.
10. Apparatus of claim 1 wherein the heat exchanger is selected
from the group consisting of plate heat exchangers, regenerative
heat exchangers, adiabatic wheel heat exchanger, fluid heat
exchangers, dynamic scraped surface heat exchanger, phase-change
heat exchangers, multi-phase heat exchangers and spiral heat
exchangers.
11. Apparatus of claim 1 wherein the container is in fluid
communication with the heat exchanger by way of at least one fluid
channel.
12. Apparatus of claim 11 wherein at least one fluid channel
extending from the heat exchanger is coupled to an orifice
contained on an underside of the container.
13. Apparatus of claim 1 wherein the second fluid is air.
14. Apparatus of claim 1 wherein the second fluid is circulated
between the heat exchanger and the container.
15. Apparatus of claim 1 wherein the raw material is resin for
producing plastics.
16. A method for pre-heating raw material using a heat exchanger
comprising: a) providing a circulation loop between a molding
apparatus and a heat exchanger; b) circulating a first fluid
through the circulation loop such that heat captured by the first
fluid from the molding apparatus is directed to the heat exchanger;
c) transferring heat captured by the first fluid to a second fluid
within the heat exchanger; d) redirecting the second fluid from the
heat exchanger to a container housing raw material for processing
in the molding apparatus; and e) transferring heat of the second
fluid to the raw material so as to heat the raw material prior to
processing in the molding apparatus.
17. The method of claim 16 wherein the circulation loop, the
molding apparatus and the heat exchanger provide a continuous
unidirectional loop therebetween such that the first fluid is
heated in the molding apparatus and cooled in the heat
exchanger.
18. The method of claim 16 wherein heat is transferred from the
first fluid to the second fluid by a convective current created by
the second fluid such that heat is transferred without mixing the
first fluid and the second fluid.
19. The method of claim 16 further comprising circulating the
second fluid through a circulation loop between the heat exchanger
and the container such that the circulation loop provides a
continuous unidirectional loop therebetween such that the second
fluid is heated in the heat exchanger and cooled in the
container.
20. The method of claim 16 wherein the raw materials are comprised
of resin used for producing plastics.
21. A method for pre-heating plastic resin using a heat exchanger
comprising: a) providing a first circulation loop between at least
one fluid channel of a molding apparatus and a heat exchanger; b)
providing a second circulation loop between the heat exchanger and
a container housing raw materials for molding in the molding
apparatus; c) circulating a first fluid through the first
circulation loop such that heat captured by the first fluid within
at least one fluid channel of the molding apparatus is directed to
the heat exchanger; and d) circulating a second fluid through the
second circulation loop such that heat transferred from the first
fluid to the second fluid within the heat exchanger is directed to
an interior of the container housing plastic resin for processing
in the molding apparatus wherein the plastic resin is heated prior
to processing in the molding apparatus.
Description
FIELD OF THE INVENTION
[0001] This invention relates to apparatus and methods for
recovering heat from a molded product and/or the machine in which
the product is molded and applying the recovered heat to resin
prior to molding. More specifically, this invention conserves
energy by recirculating heat captured from the molded product
and/or the molding machine to pre-heat the raw resin molding
material, before the raw resin material enters an extruder or a
molding apparatus.
BACKGROUND OF THE INVENTION
[0002] Molded products, such as plastics, and the like, have been
known for decades and are used, inter alia, for product packaging,
product presentation, material storage, and the like. Because of
their widely-varying nature and characteristics, energy efficient
methods of producing these items are a necessity. Of particular
interest are methods to quickly cool a molded product, particularly
within the context of manufacturing facilities.
[0003] Previous methods of cooling, while effective in cooling a
product of interest, are wasteful in failing to recapture heat lost
during processing. Rather than being reused, the heat was entirely
lost, thus increasing energy costs by requiring more heat in
earlier processing steps. Known systems and methods are largely
inefficient, thereby increasing operating costs of molding and
manufacturing molded products.
[0004] Early cooling methods included the application of either
ambient air from a fan or compressed air blown across the molded
product immediately after molding. These convective cooling methods
removed heat from the molded product. The removed heat, however,
was not contained within a closed system, but was wastefully lost.
Thus, while the molding method achieved its objective, it was
largely inefficient, as additional energy was required to create
the required heat in earlier processing steps.
[0005] U.S. Pat. No. 4,657,574 discloses cooling molded glass using
a rod-shaped material of higher thermal conductivity than the mold.
Specifically, the rod-shaped material extends through the mold in a
position proximate to the heated product, where the rod is able to
extract heat from the heated product and then withdraw into a
recess. This apparatus and method is largely inefficient because
the heat extracted from the resulting product is not reused within
the system but is lost.
[0006] U.S. Pat. Nos. 4,313,751; 5,398,745; 5,824,237; and
7,303,387 disclose alternative methods of cooling a molded product
using convective fluid flow. Specifically, each of these patents
discloses a molding machine with one or more channels passing
through the mold, proximate to the heated product. A cooling
medium, e.g. water, may be passed through these channels and,
ultimately, through the mold itself. As it passes through the mold,
the cooling medium extracts heat from the molded product that is
the mold using convective cooling mechanisms. While these
approaches appropriately cool the heated product, they do not use
the extracted heat in any way. Rather, the heat is largely lost,
providing inefficiency within the system.
[0007] U.S. Pat. No. 3,758,866 discloses an alternative wherein a
heated product is cooled using a larger refrigeration system. A
first loop of circulated cooling fluid passes through channels of
the mold and through a heat exchanger. As the fluid of the first
loop passes through the mold, the fluid receives heat, thereby
cooling the molded product. The heated fluid then passes into a
heat exchanger in which fluid from a second coolant loop extracts
the heat from first loop. The fluid from the first loop is then
recirculated back through the mold and the fluid from the second
loop is provided to a compressor and an associated condenser, where
it is cooled and recirculated to the heat exchanger. While this
system uses multiple processing steps to provide a circulation
system for lowering the temperature of the mold, there is no
reapplication of the captured heat back to the molding process.
Thus, this system does not maximize efficiency of a molding
method.
[0008] Based on the foregoing, apparatus and methods for cooling a
molded product with little to no loss of the recaptured heat are
desirable. Apparatus and methods are further desirable that
recapture heat from the molded product and apply that heat to one
or more earlier steps in the molding process. Finally, apparatus
and methods are desirable for extracting heat from the molded
product and reapplying that heat to un-molded resin such that the
resin is heated prior to being molded.
[0009] This invention addresses these needs.
SUMMARY OF THE INVENTION
[0010] This invention relates to molding apparatus and methods for
recapturing and reusing heat from a molded product. More
specifically, this invention provides apparatus and methods for
recapturing heat from a molded product and circulating the heat to
raw material, namely resin, to facilitate heating the raw material,
to at least warm it prior to molding. Accordingly, this invention
provides apparatus and methods for conserving energy in molding
processes, making these processes more energy and cost
efficient.
[0011] In one of its manifestations, the apparatus and methods of
this invention include a molding press, a heat exchanger, a raw
material container, and one or more fluid channels providing
thermal connection among these elements. The fluid channels may be
in the form of a continuous loop between the molding press and the
heat exchanger where heat from the molded product in the molding
press is transferred to the heat exchanger by first fluid flow
within these channels. The fluid channels establish a convective
flow between the molding press and the heat exchanger such that
heat from a molded product and the proximate portion of the molding
press is transferred from the molding press to the heat
exchanger.
[0012] Heat directed into the heat exchanger is then preferably
transferred to a second fluid medium such that the first fluid is
cooled and the second fluid is heated. The cooled first fluid is
then preferably recirculated back to the molding press and the
heated second fluid is preferably redirected into a container
housing raw material to be molded, preferably plastic resin. Within
this container, heat from the second fluid is absorbed by the
materials to be molded, thereby heating the materials to be molded
and cooling the second fluid, which is then evacuated from the
container into either the surrounding environment or back into the
heat exchanger. To this end, the apparatus and methods of this
invention provide a circulation system adapted to extract heat from
the molded product produced by the molding press and to apply this
heat to raw material awaiting molding in container.
[0013] In a preferred embodiment, the first fluid is water, which
is circulated through the molding press and heat exchanger via one
or more channels. In the molding press, the water absorbs heat from
the molded product and the surrounding part of the molding press,
resulting in an increase in the temperature of the water and
cooling of the molded product. The heated water then flows into the
heat exchanger.
[0014] In the heat exchanger, ambient air is preferably directed
along and/or across the fluid channels housing the water, thereby
extracting heat from the water. As the heat is extracted, the water
is cooled and air flow is proportionately increased, resulting in a
transfer of heat from one medium to the other. The heated air is
then redirected into and through a container housing raw resin that
is ready to be molded. As the air passes through the container,
heat from the air is absorbed by the resin, thereby heating the
resin and cooling the air. The cooled air is then evacuated from
the container and, optionally, recirculated back to the heat
exchanger.
[0015] In effect, this invention recovers heat coming from a molded
product within the molding press and reuses this heat in an earlier
process step. This is advantageous because it provides cost and
energy efficiency to the overall molding process.
DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is a schematic front elevation of apparatus
manifesting aspects of the invention, illustrating in schematic
form a generic molding apparatus, a generic heat exchanger, and a
raw material container, with fluid flow provided therebetween.
[0017] FIG. 2 is a schematic isometric view of the FIG. 1 molding
apparatus, having a plurality of fluid flow channels passing
therethrough.
[0018] FIGS. 3A through 3C are schematic isometric views of the
generic shell-tube type heat exchanger depicted in FIG. 1, having a
first fluid flow channel passing therethrough and a flow path for a
second fluid across the first fluid flow channel. FIG. 3A depicts a
parallel-flow shell-tube type heat exchanger; FIG. 3B depicts a
counterflow shell-tube type heat exchanger; and FIG. 3C depicts a
cross-flow shell-tube type heat exchanger.
[0019] FIG. 4A is a schematic depiction of laminar fluid flow; FIG.
4B is a schematic depiction of turbulent fluid flow.
[0020] FIG. 5 is a flow chart depicting process aspects of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0021] This invention relates to a molding apparatus, especially
molding presses, and methods facilitating recapture and reuse of
heat produced in the course of molding a product. More
specifically, this invention provides apparatus and methods for
recapturing heat produced in the course of fabricating a molded
product and circulating the recaptured heat to raw material
awaiting molding, to heat these materials prior to molding them,
thereby reducing the amount of heat required during the actual
molding process. Accordingly, this invention provides apparatus and
methods for conserving energy in molding processes, thereby making
the processes more energy and cost efficient.
[0022] Referring to FIG. 1, a schematic, generic representation of
apparatus manifesting aspects of the invention is generally
indicated by reference number 1. In this embodiment of the
invention, the apparatus includes, at least, a molding apparatus,
desirably a molding press, illustrated schematically as 5, a heat
exchanger 10, a raw material container 65, and channels 15, 60, 70
for fluid flow. A first set of one or more channels 15 provides a
continuous loop between molding apparatus 5 and heat exchanger 10
wherein heat from a molded product produced within molding
apparatus 5 is carried to heat exchanger 10 by fluid within
channels 15. To this end, channels 15 pass through molding
apparatus 5 where a first fluid within channels 15 absorbs heat
from the molded product within apparatus 5 and from parts of
apparatus 5 that are proximate to the molded product. This heated
fluid then travels from molding apparatus 5 in the direction of
arrows A towards and into heat exchanger 15.
[0023] Within heat exchanger 10, heat stored within the first fluid
is transferred to a second fluid such that the first fluid is
cooled and the second fluid is heated. While the cooled first fluid
is recirculated back to molding apparatus 5, the heated second
fluid is then directed along channel 70 towards and into raw
material container 65. As the second fluid passes through container
65, heat from the second fluid is absorbed by the raw material in
container 65 resulting in overall heating of the raw materials
prior to processing. The second fluid is cooled as it passes
through container 65 and gives up its heat to the raw material
within container 65. The second fluid may be either evacuated to
the surrounding environment or recirculated back towards heat
exchanger 10 by channel 60. To this end, in the schematically
illustrated embodiment, the apparatus and method provide a dual
circulation system for extracting heat from the molded product
produced by molding apparatus 5 and applying this heat to raw
material within container 65.
[0024] Referring to FIG. 2, a schematic representation of a molding
apparatus 5 is illustrated. Molding apparatus 5 is illustrated as
including two halves 20, 25, each having an interior surface 35 and
an exterior surface 40. Most preferably, the interior surfaces 35
of each half 20, 25 are aligned such that, when connected, the two
halves 20, 25 define one or more hollow chambers 30, typically
referred to as "mold cavities", therebetween. The hollow chamber(s)
30 are configured to form a molded product, which may be of any
desirable shape or configuration, e.g. preforms, containers, or any
other articles that are formed by compression, injection or blow
molding. The hollow chamber(s) 30, and molding apparatus 5, may be
adapted to receive any type of material that is known in the art
for molding. Such materials may include, but are not limited to,
glass, metals, plastics, ceramics, and the like. The preferred
material is resin used to mold plastic products.
[0025] The molding halves, which define the mold, may be made of
any material known in the art for use in a molding apparatus. For
example, the mold may be a steel alloy or cast iron halves that are
held together using any suitable means. Accordingly, the size,
shape, composition, etc. of the molding apparatus is not limiting
as respecting this invention. Rather, molding apparatus 5 as
illustrated schematically may be any form or type of molding
apparatus that is known in the art such as, but not limited to,
stretch blow-molding apparatus, injection molding apparatus,
compression molding apparatus, thermomolding or thermoforming
apparatus, vacuum forming apparatus, transfer molding apparatus,
extrusion apparatus, rotational molding apparatus, and the like.
The molding apparatus 5 may include additional elements known in
the art as being useful for molding such as, but not limited to,
non-stick surfaces, specialty heat dissipating surfaces, and the
like.
[0026] In any of the forgoing forms and embodiments, molding
apparatus 5 includes one or more fluid channel portions designed C
where "C" denotes the fluid flow throughout portions of channels 15
that are within molding apparatus 5, facilitating cooling fluid
flow through or around molding apparatus 5 in positions adjacent to
hollow cavity 30 so as to be thermally coupled thereto. As
illustrated in FIG. 2, the channels 15 may pass from one side of
the exterior surface of a mold half, through the interior of the
mold, and out an opposite side of the exterior surface of a mold
half. Most preferably, the channels 15 pass through or about the
mold halves such that fluid within the channels receive heat that
is conducted, convected and/or radiated from the molded product,
with such heat flow being represented by arrows B of FIG. 2. Heat
flow through the unmarked structure that thermally couples hollow
mold cavity 30 to portion C of channel 15 is denoted by letter "B"
in FIG. 2.
[0027] While FIG. 2 illustrates four such channels passing through
the mold, the invention is not so limited. Rather, this invention
may include more or fewer channels, based on the desired and
effective rates of cooling the molded product. While channels 15
are illustrated in FIG. 2 as passing directly through molding
apparatus 5, this invention is not limited to this configuration.
Rather, the channel(s) may be rounded or adapted to substantially
encircle the molded product one or multiple times so as to increase
the surface area exposed to recover heat from the molded
product.
[0028] Channels 15 provide primarily convective cooling for
lowering the temperature of the molded product. To facilitate this
objective, channels 15 may be formed from any suitable thermally
conductive material, typically a high melting point metal. The
thermally conductive channels 15 may be the same material as
molding apparatus 5 and/or may be integrally formed therein and
extend therefrom. Accordingly, channels 15 may be comprised of
bores machined through molding apparatus 5 that are coupled to and
in fluid communication with external portions of the channels
passing between molding apparatus 5 and heat exchanger 10, as shown
in FIG. 1. In such an arrangement, it may also be desirable that
channels 15 be comprised of a thermally conductive surface within
the molding apparatus, but be insulated at the exterior portions
extending between molding apparatus 5 and heat exchanger 10. In
such an embodiment, heat extracted into the channels 15 within the
molding apparatus is not lost when traveling along channel 15 to
heat exchanger 10. Such insulation may be provided by a means
exterior to these portions of the channel 15, e.g. an insulative
jacket, or by a variation in the composition of channel 15 at these
positions, to provide such insulative properties.
[0029] Alternatively, the thermally conductive material of channels
15 may be comprised of a different, preferably more conductive,
material than molding apparatus 5. In this approach, channels 15
may be configured as a continuous loop, where the channels pass
through bores machined into molding apparatus 5. Most preferably,
bore diameter is essentially the same as the exterior diameter of
the channel such that the channels may be easily coupled to the
molding apparatus. Again, the portions of the channel 15 not
contained within molding apparatus 5 or heat exchanger 10 should be
insulated such that heat is not lost as the fluid travels
therebetween.
[0030] A cooling medium is conveyed through channels 15 to
facilitate convective extraction of heat from the molded product.
This cooling medium may be any suitable thermally conductive fluid.
Such cooling fluids may include, but are not limited to, water,
air, oil, refrigerant, and the like. Most preferably, the cooling
medium is water. As illustrated by arrows C in FIG. 2, flow of the
thermally conductive fluid may provide a current of fluid passing
very close to the hollow cavity(s) 30. The fluid flow may be
laminar, as depicted in FIG. 4A, wherein fluid glides through the
channel in smooth layers with the innermost layer typically flowing
at a higher rate than the outermost layer. More preferably,
however, the fluid flow is turbulent, as depicted in FIG. 4B,
wherein the flow is agitated rather than smooth. Turbulent flow is
preferred because laminar flow tends to develop an insulating
blanket around the channel wall, thus reducing heat transfer.
Turbulent flow, however, being agitated, thereby prevents any such
insulating blanket and allows a greater surface area of the fluid
to conduct heat. To this end, the cooling medium turbulently flows
through the molding apparatus 5 extracting heat from the molded
product within the hollow cavity(s) 30. This results in an increase
in the temperature of the cooling medium as it passes through the
molding apparatus 5 and a decrease in the temperature of the molded
product within the hollow cavity(s) 30.
[0031] Fluid within channels 15 may be provided by a storage tank
(not illustrated) or some alternative source that is connected to
the circulation loop formed by channels 15. To this end channels 15
may be in communication with the tank or the other source by a
separate channel (not illustrated) wherein the separate channel may
be selectively opened or closed so as to control or replenish the
fluid supply within channels 15.
[0032] Circulation of fluid within channels 15 may be controlled by
a pump (not illustrated) or other similar means. Most preferably a
pump is positioned between heat exchanger 10 and molding apparatus
5 such that the fluid exiting heat exchanger is pumped back into
molding apparatus 5, as illustrated by arrow A in FIG. 1. The pump
may be a conventional or commercially available centrifugal pump,
or the like.
[0033] The foregoing embodiment of molding apparatus 5 and channels
15 is not intended to be limiting. Rather, molding apparatus 5, to
include channels 15, may be adapted from molding apparatus
previously known. For example, the molding apparatus of this
invention may be comprised of any of the embodiments disclosed in
U.S. Pat. Nos. 3,748,866; 4,657,574; 5,398,745; 5,824,237; and
7,303,387, the disclosures of which are incorporated by reference
herein. Each of these patents provides a known molding apparatus
with one or more channels passing therethrough or thereabout.
Accordingly, the molding apparatus and channels of this invention
may be adapted as provided in these patents, or any other similar
type of molding apparatus that is known in the art and is in
accordance with the teachings of this invention.
[0034] Turning to FIGS. 3A through 3C, one embodiment of heat
exchanger 10 is illustrated wherein the heat exchanger is adapted
to extract heat from channels 15. As illustrated, heat exchanger 10
may be comprised of a conventional shell-tube heat exchanger having
an insulative shell 45 encasing one or more channels 15. To this
end, the apparatus may include one heat exchanger 10 encasing all
of channels 15. Alternatively, there may be multiple heat
exchangers in fluid communication, where each heat exchanger
individually encases a single channel 15.
[0035] The heat exchanger 10 preferably utilizes convective methods
to extract heat from fluid within channels 15. Most preferably,
heat exchanger 10 provides a second thermally conductive fluid,
typically air, flowing across the exterior surface of channel 15.
The convective current established by the air flow, which is
preferably at ambient temperature, extracts the heat from the
channels, thereby heating the fluid in the heat exchanger 10 and
cooling the fluid within channels 15. The fluid flow within heat
exchanger 10 may be either laminar or turbulent, with turbulent
being preferred for the reasons discussed above. Accordingly, the
heat exchanger may also include one or more fins or corrugations in
one or both directions, which increase surface area and may channel
fluid flow or induce turbulence.
[0036] The shell-tube heat exchanger may be a parallel-flow heat
exchanger, a counterflow heat exchanger or a cross-flow heat
exchanger. Referring to FIG. 3A, the illustrated heat exchanger
facilitates parallel-flow heat exchange wherein the fluid flow
within the heat exchanger as indicated by arrow E, is parallel to
the fluid flow in the channels as indicated by arrow D. More
specifically, shell 45 includes two orifices 50, 55 on opposing
sides and opposing ends of shell 45. Air flows through the first
orifice 50, through the interior of shell 45 and out of second
orifice 55. The fluids in the shell 45 and in the channels 15,
while not actually mixing, are in concert with each other. To this
end, as fluid from heat exchanger 10 travels along the exterior of
channels 15, heat from the fluid in channels 15 is extracted.
Ultimately, this increases the temperature of the fluid within heat
exchanger 10 and decreases the temperature of the fluid within
channels 15. Most preferably, fluid within channels 15 is reduced
to ambient temperature and fluid within heat exchanger 10 increases
a proportionate amount such that heat is efficiently transferred
from one fluid to the other.
[0037] Referring to FIG. 3B, the schematically illustrated heat
exchanger facilitates counter-flow heat exchange wherein fluid flow
within the heat exchanger as indicated by arrow F, is opposite in
direction to that of fluid flow within the channels, as indicated
by arrow D. More specifically, shell 45 includes two orifices 50,
55 on opposing sides and opposing ends respectively of shell 45.
Air flows through second orifice 55, through the interior of shell
45 and out of first orifice 50. The respective fluids within shell
45 and channels 15, while not actually mixing, flow in parallel
paths that are directly opposite of one other. To this end, as
fluid from heat exchanger 10 travels along the exterior sides of
channels 15, heat from the fluid in the channels is extracted. This
method is preferred as it provides the most efficient transfer of
heat from the fluid within channels 15 to the fluid within the
shell of heat exchanger 10. As with the previous embodiment, most
preferably the temperature of the fluid within the channels is
reduced to close to ambient temperature while the fluid within the
heat exchanger shell increases a proportionate amount.
[0038] Referring to FIG. 3C, there is a schematically illustrated
cross-flow heat exchanger wherein fluid flow within the shell of
the heat exchanger, flowing in the direction indicated by arrow G,
is substantially perpendicular to the direction of fluid flow
within the channels, as indicated by arrow D. More specifically,
shell 45 includes at least two orifices 50, 55 on opposing sides
and may be located at any point along the length of shell 45. Air
flows through first orifice 50, through the interior of shell 45
and out second orifice 55. The respective fluids in the shell 45
and in the channels 15, while not actually mixing, flow almost
perpendicular to each other. To this end, as fluid from heat
exchanger 10 travels along the exterior of channels 15, heat from
the fluid in the channels is extracted. Ultimately, this increases
the temperature of the fluid within the heat exchanger shell and
decreases the temperature of the fluid flowing within the channels.
Most preferably, the temperature of fluid flowing within the
channels is reduced to close to ambient temperature and the
temperature of the fluid flowing within the shell of the heat
exchanger increases. While FIG. 3C illustrates two orifices 50, 50
aligned on opposing sides of the heat exchanger shell, this
invention is not limited to this configuration. In an alternative
embodiment, the shell 45 may include multiple orifices aligned with
one another on opposing sides of the shell 45 and along the length
of the shell such that the heat exchanger provides multiple points
along the shell for cross-flow over channels 15. Such an embodiment
would further maximize heat extraction within the heat
exchanger.
[0039] This invention is not limited to the foregoing heat
exchangers and may be adapted to include any similar type of heat
exchanger known in the art. Non-limiting examples of other types of
heat exchangers include, but are not limited to, plate heat
exchangers, regenerative heat exchangers, adiabatic wheel heat
exchangers, fluid heat exchangers, dynamic scraped surface heat
exchangers, phase-change heat exchangers, multi-phase heat
exchangers, spiral heat exchangers, and the like.
[0040] The fluid flow rate of the heat exchanger may be requested
by any means known in the art. For example, the fluid flowing
through shell 45 of the heat exchanger may be provided by a pump
which has not been illustrated. Most preferably, such a pump forces
ambient fluid, e.g. air, into the targeted orifice of shell 45 such
that a fluid flow path is established into and through the opposing
orifice of shell 45. While air may be provided as one exemplary
fluid, this invention is not limited to this configuration and any
fluid known in the art as being suitable for use in a heat
exchanger may be used.
[0041] Referring to FIG. 1, heat exchanger 10 is preferably placed
into communication with a container 65 of raw material to heat the
material prior to processing. More specifically, the heated fluid
exiting heat exchanger 10, indicated by arrow H, is redirected
through one or more insulated channels 70 into container 65. The
heated fluid may be applied to the raw material using any method
known in the art. More preferably, however, the heated fluid is
applied to the raw material through one or more orifices on the
underside of container 65. Most preferably, the heated fluid may be
applied to the resin prior to molding at a position substantially
underneath the container such that the resin to be molded is evenly
heated by air, as the heated air rises within the container. Air
flow from the heat exchanger forces the heated fluid into and
through container 65. As the heated fluid passes through the
container, the heat is absorbed by the raw resin material contained
therein, thereby cooling the fluid. This cooled fluid is then
evacuated from the container into the environment or used in
accordance with methods discussed herein. The heat extracted from
the molded product is desirably ultimately reapplied to heat more
raw material prior to processing into a molded product.
[0042] In an even further embodiment, as illustrated in FIG. 1,
cooled fluid evacuated from container 65 is recirculated back to
heat exchanger 10. In this embodiment fluid flow between heat
exchanger 10 and the raw material provides a second circulation
loop for transfer of heat from heat exchanger 10 to container 65
and the material therein. This second circulation loop is optional.
Rather, the evacuated air may be reintroduced to the surrounding
environment with the pump attached to the heat exchanger
resupplying ambient air in accordance with the foregoing.
[0043] The raw materials within container 65 may be resin or other
particles used for the manufacture of plastic. To this end, the
heated fluid from the heat exchanger 10 pre-heats the resin before
the resin is processed. This invention, however, is not limited to
this embodiment and may include any raw materials known in the art
for manufacturing any molded product.
[0044] In an even further embodiment of this invention, a
compressor or heat pump may, optionally, be added to the system at
any point between the heat exchanger 10 and the raw material 65.
The compressor or pump may be used to increase pressure of the
heated second fluid such that it is able to flow completely through
container 65 and increase effectiveness of the air flow. Most
preferably, the compressor or heat pump may be placed between the
heat exchanger 10 and the container 65 at any point along channel
70 such that the compressor or heat pump is in fluid communication
therewith. The compressor may be any type of compressor known in
the art such as, but not limited to, centrifugal compressors,
mixed-flow compressors, axial-flow compressors, reciprocating
compressors, rotary screw compressors, rotary vane compressors,
scroll compressors, diaphragm compressors, or the like. Similarly,
the heat pump may be any heat pump that is known in the art such
as, but not limited to, compression heat pumps, absorption heat
pumps, and the like.
[0045] Referring to FIG. 5, a flow chart of process aspects of the
invention is illustrated. As shown, water from the heat exchanger,
or alternatively an external source, is provided and preferably
pumped into the molding apparatus by way of one or more channels.
As the water passes through the molding apparatus, it absorbs heat
from the mold, thereby increasing its temperature and cooling the
temperature of the molded product. The heated water then travels
from the molding apparatus to the heat exchanger by way of one or
more preferably insulated channels.
[0046] As the heated water travels into the heat exchanger, ambient
air is directed along and ultimately across the channels. As the
ambient air flows along the channels it extracts heat from water in
the channels, thereby cooling the water and proportionately
increasing the air such that minimal heat is lost. The heated air
is then redirected, preferably pumped, into a container housing
resin to be molded. As the heated air passes through the container,
the heat is absorbed by the resin, thereby pre-heating the resin
and cooling the air. Accordingly, the resin is heated prior to
molding using heat recaptured from later processing steps. The
cooled air may then, optionally, be recirculated back to the heat
exchanger where it continues to absorb heat from the channels. This
process continues until the molded product is completely cooled
and/or the resin is pre-heated to a level sufficient for
processing.
[0047] This invention is advantageous because it provides cost and
energy efficiency to the overall molding processes. It is estimated
that the foregoing apparatus and methods may save a molded product
manufacturer approximately 1/10 to 1/5 a cent per pound of raw
material, namely resin, processed. In a standard manufacturing
facility, this may translate into a savings of at least $40,000 per
year. Additional advantages of this invention will be readily
apparent to one of ordinary skill in the art.
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