U.S. patent application number 13/671237 was filed with the patent office on 2013-05-09 for reversible flow inducer.
This patent application is currently assigned to GRACO MINNESOTA INC.. The applicant listed for this patent is GRACO MINNESOTA INC.. Invention is credited to Paul R. Quam, Daniel P. Ross.
Application Number | 20130112312 13/671237 |
Document ID | / |
Family ID | 48222892 |
Filed Date | 2013-05-09 |
United States Patent
Application |
20130112312 |
Kind Code |
A1 |
Ross; Daniel P. ; et
al. |
May 9, 2013 |
REVERSIBLE FLOW INDUCER
Abstract
A hot melt dispensing system includes a container for storing
adhesive pellets, a melt system for heating adhesive pellets into a
liquid, and a feed system connecting the container to the melt
system. The feed system includes a reversible flow inducer having a
first position for directing air flow toward the melt system. The
reversible flow inducer also has a second position for directing
air flow toward the container.
Inventors: |
Ross; Daniel P.; (Maplewood,
MN) ; Quam; Paul R.; (Minneapolis, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GRACO MINNESOTA INC.; |
Minneapolis |
MN |
US |
|
|
Assignee: |
GRACO MINNESOTA INC.
Minneapolis
MN
|
Family ID: |
48222892 |
Appl. No.: |
13/671237 |
Filed: |
November 7, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61556578 |
Nov 7, 2011 |
|
|
|
Current U.S.
Class: |
141/2 ;
141/18 |
Current CPC
Class: |
B05C 11/1042 20130101;
B05C 11/1047 20130101; F16K 5/0605 20130101; B05C 5/02 20130101;
B05C 5/0245 20130101; B65B 1/16 20130101; B05B 9/0403 20130101 |
Class at
Publication: |
141/2 ;
141/18 |
International
Class: |
B65B 1/16 20060101
B65B001/16 |
Claims
1. A hot melt dispensing system comprising: a container for storing
adhesive pellets; a melt system for heating adhesive pellets into a
liquid; and a feed system connecting the container to the melt
system, the feed system comprising: a reversible flow inducer
having a first position for feeding adhesive pellets from the
container to the melt system and a second position for returning
adhesive pellets from the feed system to the container.
2. The hot melt dispensing system of claim 1, wherein the
reversible flow inducer is a Venturi vacuum assembly that creates a
vacuum in the feed system for inducing flow of adhesive
pellets.
3. The hot melt dispensing system of claim 1, wherein the
reversible flow inducer is connected to an outlet of the container,
and wherein the feed system further comprises: a feed hose
connecting the reversible flow inducer to the melt system.
4. The hot melt dispensing system of claim 1, wherein the
reversible flow inducer comprises: a nozzle for directing air flow;
and a handle for moving the nozzle between first and second
directions.
5. The hot melt dispensing system of claim 1, wherein the container
comprises a hopper with a pellet inlet at a top of the hopper and a
pellet outlet at a bottom of the hopper.
6. The hot melt dispensing system of claim 1, wherein a portion of
the container is substantially funnel shaped.
7. A hot melt dispensing system comprising: a container for storing
adhesive pellets; a melt system for heating adhesive pellets into a
liquid; and a feed system connecting the container to the melt
system, the feed system comprising: a reversible flow inducer
having a first position for directing air flow toward the melt
system and a second position for directing air flow toward the
container.
8. The hot melt dispensing system of claim 7, wherein the
reversible flow inducer is a Venturi vacuum assembly that creates a
low pressure zone in the feed system for inducing flow of adhesive
pellets.
9. The hot melt dispensing system of claim 7, wherein the
reversible flow inducer is connected to an outlet of the container,
and wherein the feed system further comprises: a feed hose
connecting the reversible flow inducer to the melt system.
10. The hot melt dispensing system of claim 7, wherein the
reversible flow inducer comprises: a nozzle for directing air flow;
and a handle for moving the nozzle between the first position and
the second position.
11. The hot melt dispensing system of claim 10, wherein the handle
pivots the nozzle between the first position and the second
position.
12. The hot melt dispensing system of claim 7, wherein the
reversible flow inducer comprises: a reversible nozzle having a
nozzle body defining a plurality of ports positioned
circumferentially around a pellet passage.
13. The hot melt dispensing system of claim 7, wherein the
reversible flow inducer comprises: a vacuum assembly housing having
a Venturi air inlet; and a reversible nozzle having a Venturi air
outlet port in fluid communication with the Venturi air inlet.
14. The hot melt dispensing system of claim 7, wherein the
container comprises a hopper with a pellet inlet at a top of the
hopper and a pellet outlet at a bottom of the hopper.
15. The hot melt dispensing system of claim 7, wherein the
reversible flow inducer is connected to an outlet of the
container.
16. A method of operating a hot melt dispensing system, the method
comprising: directing air toward a melt system via a reversible
flow inducer when the reversible flow inducer is in a first
position, wherein the reversible flow inducer is part of a feed
system connecting a container of adhesive pellets to the melt
system; moving the reversible flow inducer to a second position;
and directing air toward the container via the reversible flow
inducer when the reversible flow inducer is in the second
position.
17. The method of claim 16, and further comprising: supplying air
to the reversible flow inducer to create a Venturi vacuum to induce
flow of adhesive pellets.
18. The method of claim 16, wherein the reversible flow inducer
creates a suction to draw adhesive pellets from the container to
the reversible flow inducer and then blows the adhesive pellets
from the reversible flow inducer to the melt system when the
reversible flow inducer is in the first position.
19. The method of claim 16, wherein a feed hose connects the
reversible flow inducer to the melt system and wherein the
reversible flow inducer creates a suction to draw adhesive pellets
from the feed hose to the reversible flow inducer and then blows
the adhesive pellets from the reversible flow inducer to the
container when the reversible flow inducer is in the second
position.
20. The method of claim 16, wherein the reversible flow inducer
returns adhesive pellets to the container when the reversible flow
inducer is in the second position, and further comprising:
replacing the container with a replacement container after the
adhesive pellets are returned to the container.
Description
BACKGROUND
[0001] The present disclosure relates generally to systems for
dispensing hot melt adhesive. More particularly, the present
disclosure relates to feeding solid adhesive pellets in a system
for dispensing hot melt adhesive.
[0002] Hot melt dispensing systems are typically used in
manufacturing assembly lines to automatically disperse an adhesive
used in the construction of packaging materials such as boxes,
cartons and the like. Hot melt dispensing systems conventionally
comprise a material tank, heating elements, a pump and a dispenser.
Solid polymer pellets are melted in the tank using a heating
element before being supplied to the dispenser by the pump. Because
the melted pellets will re-solidify into solid form if permitted to
cool, the melted pellets must be maintained at temperature from the
tank to the dispenser. This typically requires placement of heating
elements in the tank, the pump and the dispenser, as well as
heating any tubing or hoses that connect those components.
Furthermore, conventional hot melt dispensing systems typically
utilize tanks having large volumes so that extended periods of
dispensing can occur after the pellets contained therein are
melted. However, the large volume of pellets within the tank
requires a lengthy period of time to completely melt, which
increases start-up times for the system. For example, a typical
tank includes a plurality of heating elements lining the walls of a
rectangular, gravity-fed tank such that melted pellets along the
walls prevents the heating elements from efficiently melting
pellets in the center of the container. The extended time required
to melt the pellets in these tanks increases the likelihood of
"charring" or darkening of the adhesive due to prolonged heat
exposure.
SUMMARY
[0003] According to the present invention, a hot melt dispensing
system includes a container for storing adhesive pellets, a melt
system for heating adhesive pellets into a liquid, and a feed
system connecting the container to the melt system. The feed system
includes a reversible flow inducer having a first position for
feeding adhesive pellets from the container to the melt system. The
reversible flow inducer also has a second position for returning
adhesive pellets from the feed system to the container.
[0004] Another embodiment is a hot melt dispensing system including
a container for storing adhesive pellets, a melt system for heating
adhesive pellets into a liquid, and a feed system connecting the
container to the melt system. The feed system includes a reversible
flow inducer having a first position for directing air flow toward
the melt system. The reversible flow inducer also has a second
position for directing air flow toward the container.
[0005] Another embodiment is a method of operating a hot melt
dispensing system. The method includes directing air toward a melt
system via a reversible flow inducer when the reversible flow
inducer is in a first position, moving the reversible flow inducer
to a second position, and directing air toward a container of
adhesive pellets via the reversible flow inducer when the
reversible flow inducer is in the second position. The reversible
flow inducer is part of a feed system connecting the container to
the melt system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a schematic view of a system for dispensing hot
melt adhesive.
[0007] FIG. 2 is a side sectional view of a container and a feed
assembly for use in the system of FIG. 1.
[0008] FIG. 3A is a side sectional view of a flow inducer in a
first position for use in the feed assembly of FIG. 2.
[0009] FIG. 3B is a side sectional view of the flow inducer of FIG.
3A in a second position.
DETAILED DESCRIPTION
[0010] FIG. 1 is a schematic view of system 10, which is a system
for dispensing hot melt adhesive. System 10 includes cold section
12, hot section 14, air source 16, air control valve 17, and
controller 18. In the embodiment shown in FIG. 1, cold section 12
includes container 20 and feed assembly 22, which includes vacuum
assembly 24, feed hose 26, and inlet 28. In the embodiment shown in
FIG. 1, hot section 14 includes melt system 30, pump 32, and
dispenser 34. Air source 16 is a source of compressed air supplied
to components of system 10 in both cold section 12 and hot section
14. Air control valve 17 is connected to air source 16 via air hose
35A, and selectively controls air flow from air source 16 through
air hose 35B to vacuum assembly 24 and through air hose 35C to
motor 36 of pump 32. Air hose 35D connects air source 16 to
dispenser 34, bypassing air control valve 17. Controller 18 is
connected in communication with various components of system 10,
such as air control valve 17, melt system 30, pump 32, and/or
dispenser 34, for controlling operation of system 10.
[0011] Components of cold section 12 can be operated at room
temperature, without being heated. Container 20 can be a hopper for
containing a quantity of solid adhesive pellets for use by system
10. Suitable adhesives can include, for example, a thermoplastic
polymer glue such as ethylene vinyl acetate (EVA) or metallocene.
Feed assembly 22 connects container 20 to hot section 14 for
delivering the solid adhesive pellets from container 20 to hot
section 14. Feed assembly 22 includes vacuum assembly 24 and feed
hose 26. Compressed air from air source 16 and air control valve 17
is delivered to vacuum assembly 24 to create a vacuum, inducing
flow of solid adhesive pellets into inlet 28 of vacuum assembly 24
and then through feed hose 26 to hot section 14. Feed hose 26 is a
tube or other passage sized with a diameter substantially larger
than that of the solid adhesive pellets to allow the solid adhesive
pellets to flow freely through feed hose 26. Feed hose 26 connects
vacuum assembly 24 to hot section 14.
[0012] Solid adhesive pellets are delivered from feed hose 26 to
melt system 30. Melt system 30 can include a container (not shown)
and resistive heating elements (not shown) for melting the solid
adhesive pellets to form a hot melt adhesive in liquid form. Melt
system 30 can be sized to have a relatively small adhesive volume,
for example about 0.5 liters, and configured to melt solid adhesive
pellets in a relatively short period of time. Pump 32 is driven by
motor 36 to pump hot melt adhesive from melt system 30, through
supply hose 38, to dispenser 34. Motor 36 can be an air motor
driven by pulses of compressed air from air source 16 and air
control valve 17. Pump 32 can be a linear displacement pump driven
by motor 36. In the illustrated embodiment, dispenser 34 includes
manifold 40 and module 42. Hot melt adhesive from pump 32 is
received in manifold 40 and dispensed via module 42. Dispenser 34
can selectively discharge hot melt adhesive whereby the hot melt
adhesive is sprayed out outlet 44 of module 42 onto an object, such
as a package, a case, or another object benefiting from hot melt
adhesive dispensed by system 10. Module 42 can be one of multiple
modules that are part of dispenser 34. In an alternative
embodiment, dispenser 34 can have a different configuration, such
as a handheld gun-type dispenser. Some or all of the components in
hot section 14, including melt system 30, pump 32, supply hose 38,
and dispenser 34, can be heated to keep the hot melt adhesive in a
liquid state throughout hot section 14 during the dispensing
process.
[0013] System 10 can be part of an industrial process, for example,
for packaging and sealing cardboard packages and/or cases of
packages. In alternative embodiments, system 10 can be modified as
necessary for a particular industrial process application. For
example, in one embodiment (not shown), pump 32 can be separated
from melt system 30 and instead attached to dispenser 34. Supply
hose 38 can then connect melt system 30 to pump 32.
[0014] FIG. 2 is a side sectional view of container 20 and feed
assembly 22. Container 20 includes container housing 46, pellet
inlet 48 at a top of container housing 46, and pellet outlet 50 at
a bottom of container housing 46. Funnel 46A is a portion of
container housing 46 that is substantially funnel shaped near
pellet outlet 50. In the illustrated embodiment, funnel 46A is
angled with respect to vertical. Container 20 is a hopper that
contains a quantity of adhesive pellets 52 for use by system 10
(shown in FIG. 1).
[0015] Feed assembly 22 is a feed system fluidically connected to
pellet outlet 50 of container 20 for transporting adhesive pellets
52 from container 20 to melt system 30 (shown in FIG. 1). Inlet 28
of feed assembly 22 is a pellet inlet of vacuum assembly 24. Vacuum
assembly 24 is a flow inducer for inducing flow of air and adhesive
pellets 52. In the illustrated embodiment, vacuum assembly 24 is a
Venturi vacuum assembly having Venturi air inlet 54 and Venturi air
outlet ports 56. Distribution passage 58 fluidically connects
Venturi air inlet 54 to Venturi air outlet ports 56, which are
angled to direct air downstream through feed assembly 22. Air from
air hose 35B flows through Venturi air inlet 54, through
distribution passage 58, and out at an angle through Venturi air
outlet ports 56. Vacuum assembly 24 creates a vacuum in feed
assembly 22 to draw adhesive pellets 52 into vacuum assembly 24,
and the resulting air flow continues to push adhesive pellets 52
along through feed hose 26. The vacuum created by vacuum assembly
24 is a low pressure zone in feed assembly 22 for inducing flow of
adhesive pellets 52 from container 20. In the illustrated
embodiment, vacuum assembly 24 is a reversible flow inducer as
further described with respect to FIGS. 3A and 3B.
[0016] FIG. 3A is a side sectional view of vacuum assembly 24 in a
first position as part of feed assembly 22. Vacuum assembly 24
includes nozzle 60 and handle 62. Nozzle 60 includes nozzle body
64, which is a substantially toroidal body that defines Venturi air
outlet ports 56, distribution passage 58, and pellet passage 66.
Distribution passage 58 is a channel extending around nozzle body
64. Distribution passage 58 is aligned with Venturi air inlet 54
for distributing Venturi air to Venturi air outlet ports 56, which
direct Venturi air flow in Vacuum assembly 24 in a selectable
direction. Venturi air outlet ports 56 are positioned radially
outward of and circumferentially around pellet passage 66. Pellet
passage 66 includes pellet passage inlet 68 and pellet passage
outlet 70. Venturi air outlet ports 56 are positioned near an end
of pellet passage 66 nearest to pellet passage outlet 70. Venturi
air flowing out Venturi air outlet ports 56 creates a low pressure
zone in vacuum assembly 24 downstream of pellet passage outlet 70
so as to induce flow of air and adhesive pellets 52 (shown in FIG.
2) through pellet passage 66 in a a direction from pellet passage
inlet 68 to pellet passage outlet 70. When vacuum assembly 24 is in
the first position, vacuum assembly 24 creates a suction to draw
adhesive pellets 52 from container 20 to vacuum assembly 24, and
then blows adhesive pellets 52 from vacuum assembly 24 in a first
direction to melt system 30 (shown in FIG. 1).
[0017] Nozzle 60 is a reversible nozzle capable of movement between
first and second positions. As illustrated in FIG. 3A, nozzle 60 is
in a first position for directing air flow along feed hose 26
toward melt system 30. Handle 62 is connected to nozzle 60 via
shaft 72 for moving nozzle 60 between the first and second
positions. Shaft 72 is supported by bearings 74 to allow handle 62,
shaft 72, and nozzle 60 to pivot about an axis of shaft 72 with
respect to vacuum assembly housing 76. Nozzle 60 is pivotably
positioned in a pocket within vacuum assembly housing 76. In the
illustrated embodiment, Venturi air inlet 54 extends into vacuum
assembly housing 76 and is substantially aligned with the axis of
shaft 72.
[0018] During normal operation of system 10 (shown in FIG. 1),
nozzle 60 of vacuum assembly 24 can be in the first position
directing air flow in the first direction. In the first position,
vacuum assembly 24 can induce flow of adhesive pellets from
container 20 through feed assembly 22 to melt assembly 30. After
system 10 has completed a period of normal operation, system 10 can
be temporarily paused or shut down. In between periods of normal
operation, residual adhesive pellets 52 can remain in feed assembly
22. When system 10 is started again, those adhesive pellets 52 can
be blown by vacuum assembly 24 to melt assembly 30 to be
melted.
[0019] In some applications, system 10 can be used with different
types of adhesive pellets 52 for different applications. Between
periods of normal operation, container 20 can be disconnected and
replaced with a replacement container that contains different
adhesive pellets. In such circumstances, it can be desirable to
remove the residual adhesive pellets 52 in feed assembly 22 so to
avoid contaminating the new adhesive pellets used in the different
operations.
[0020] FIG. 3B is a side sectional view of vacuum assembly 24 with
nozzle 60 in the second position. In the second position, Venturi
air outlet ports 56 and pellet passage 66 are pointed in a second
direction toward container 20, opposite of the first direction. In
the second position, Venturi air flowing out Venturi air outlet
ports 56 creates a low pressure zone in vacuum assembly 24
downstream of pellet passage outlet 70 so as to induce flow of air
and adhesive pellets 52 (shown in FIG. 2) through pellet passage 66
in the second direction, from feed hose 26, through pellet passage
inlet 68, through pellet passage outlet 70, and into container 20.
When vacuum assembly 24 is in the second position, vacuum assembly
24 creates a suction to draw adhesive pellets 52 from feed hose 26
to vacuum assembly 24, and then blows adhesive pellets 52 from
vacuum assembly 24 to container 20. Vacuum assembly 24 can thus
return adhesive pellets 52 from feed assembly 22 to container 20.
This can be a relatively convenient way of removing adhesive
pellets 52 from feed assembly 22 prior to replacing container 20.
After adhesive pellets 52 are returned to container 20, container
20 can be replaced with a replacement container containing
different adhesive pellets. In some embodiments, container 20 can
include a shut-off valve (not shown) or other mechanism to close
pellet outlet 50.
[0021] Handle 62 allows a user to manually move vacuum assembly 24
between first and second positions as necessary. In alternative
embodiments, vacuum assembly 24 handle 62 can be omitted and vacuum
assembly 24 can be reversed automatically or via another mechanism
suitable for reversing the direction of air flow in vacuum assembly
24.
[0022] While the invention has been described with reference to
exemplary embodiments, it will be understood by those skilled in
the art that various changes may be made and equivalents may be
substituted for elements thereof without departing from the scope
of the invention. In addition, many modifications may be made to
adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiments disclosed, but that the invention will
include all embodiments falling within the scope of the appended
claims. For example, various components of system 10 can be sized,
shaped, and configured differently than as illustrated as
appropriate for a given application.
* * * * *