U.S. patent number 3,664,086 [Application Number 04/888,615] was granted by the patent office on 1972-05-23 for gas flushing system for vertical form, fill and seal machines.
This patent grant is currently assigned to Hayssen Manufacturing Company. Invention is credited to Robert C. James, Frank E. Pringle, Jr., David A. Wilson.
United States Patent |
3,664,086 |
James , et al. |
May 23, 1972 |
GAS FLUSHING SYSTEM FOR VERTICAL FORM, FILL AND SEAL MACHINES
Abstract
Gas flushing is effected by introducing the gas through one or
more ducts into a free portion of the vertical package forming,
filling and sealing tube above the area to which packaging sheet
material is fed onto and tubularly formed about the tube. At least
one of the ducts communicates with an extension duct nozzle
depending within the tube for releasing and distributing flushing
gas onto the product delivered through the tube into the formed
packaging bags. Prepurging gas may be introduced into the tube
upstream from the flushing gas. Gas sampling and machine start-up
preflushing may be effected through a duct having a combination
inlet and outlet located to extend partially downwardly into the
bag to be filled or which may have been last filled when the
machine is restarted after a shut-down.
Inventors: |
James; Robert C. (Sheboygan,
WI), Wilson; David A. (Sheboygan, WI), Pringle, Jr.;
Frank E. (Sheboygan, WI) |
Assignee: |
Hayssen Manufacturing Company
(Sheboygan, WI)
|
Family
ID: |
25393535 |
Appl.
No.: |
04/888,615 |
Filed: |
December 29, 1969 |
Current U.S.
Class: |
53/511;
141/4 |
Current CPC
Class: |
B65B
55/19 (20130101); B65B 31/045 (20130101); B65B
9/20 (20130101) |
Current International
Class: |
B65B
31/04 (20060101); B65B 55/19 (20060101); B65B
55/02 (20060101); B65B 9/20 (20060101); B65B
9/10 (20060101); B65b 031/04 () |
Field of
Search: |
;53/22A,112A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: MeGehee; Travis S.
Claims
What we claim as our invention:
1. In combination with a bag forming, filling and sealing machine
including a vertical tube having communicating therewith product
receiving head means, means spaced below said head means for
forming bag sheet material about the tube, seam sealing means
cooperative with the tube below the forming means, and combination
bag sealing, cut-off and pull-down means operative below the lower
discharge end of the tube:
an elongated nozzle member extending downwardly within said tube
and operative to discharge flushing gas into the tube for purging
atmospheric oxygen from product supplied through the tube into bags
formed below said discharge end;
means for supplying said nozzle with flushing gas through the wall
area of said tube between said head structure and said folding
means;
a gas sampling duct having an inlet end extending below said
discharge end of the tube to be effective within the next formed
bag under said discharge end;
a suction line connected to said duct above said forming means
including a valve; and
means connecting said valve with flushing gas supply for
alternatively supplying gas into the next filled bag or for
withdrawing a gas sample from such bag, under the control of said
valve.
2. In combination with a bag forming, filling and sealing machine
including a vertical tube having a product passage therein
communicating with product receiving head means, means spaced below
said head means for forming bag sheet material about the tube, seam
sealing means cooperative with the tube below the forming means,
and combination bag sealing, cut-off and pull-down means operative
below the lower discharge end of the tube:
means for supplying flushing gas adjacent to the lower end of said
passage including a nozzle and a duct leading thereto;
means for supplying flushing gas;
gas monitoring means; and
means for alternatively connecting said duct with said gas
supplying means and with said monitoring means.
3. A combination according to claim 2, said means for connecting
being also operative to open said duct to atmosphere.
4. In combination with a bag forming, filling and sealing machine
including a vertical tube having a product passage therein
communicating with product receiving head means, means spaced below
said head means for forming bag sheet material about the tube, seam
sealing means cooperative with the tube below the forming means,
and combination bag sealing, cut-off and pull-down means operative
below the lower discharge end of the tube:
an elongated nozzle member extending downwardly within said tube
passage and having a number of distribution holes along its length
within said passage operative to discharge flushing gas into the
tube passage for purging atmospheric oxygen from product as the
product moves down through the passage and before the product drops
from the discharge end into the bags that have been formed below
said discharge end; and
means for supplying said nozzle member with flushing gas through
the wall area of said tube between said head means and said folding
means including a gas source and supply line duct means connecting
the source with said nozzle and having therein a shut-off valve
adapted to be controlled in coordinated relation with the machine,
and flow-controlling means as well as pressure-regulating means and
flow-metering means in said line duct means downstream from said
valve.
5. In combination with a bag forming, filling and sealing machine
including a vertical tube having a product passage therein
communicating with product receiving head means, means spaced below
said head means for forming bag sheet material about the tube, seam
sealing means cooperative with the tube below the forming means,
and combination bag sealing, cut-off and pull-down means operative
below the lower discharge end of the tube:
an elongated nozzle member extending downwardly within said tube
passage and operative to discharge flushing gas into the tube
passage for purging atmospheric oxygen from product supplied
through the tube passage into bags formed below said discharge
end;
means for supplying said nozzle member with flushing gas through
the wall area of said tube between said head means and said folding
means;
initial purge gas means communicating with an upper portion of the
tube passage;
a gas sampling duct having an inlet end extending below said
discharge end; and
a suction line connected to said duct above said forming means.
6. In combination with a bag forming, filling and sealing machine
including a vertical tube having a product passage therein
communicating with product receiving head means, means spaced below
said head means for forming bag sheet material about the tube, seam
sealing means cooperative with the tube below the forming means,
and combination bag sealing, cut-off and pull-down means operative
below the lower discharge end of the tube:
an elongated nozzle member extending downwardly within said tube
passage and operative to discharge flushing gas into the tube
passage for purging atmospheric oxygen from the product supplied
through the tube passage into bags formed below said discharge
end;
means for supplying said nozzle member with flushing gas through
the wall area of said tube between said head means and said folding
means;
initial purge gas means communicating with an upper portion of the
tube passage;
a combination prepurge and gas sampling duct having a discharge
inlet end extending below said discharge end of the tube to be
effective within the next formed bag under said discharge end;
and
means for alternatively connecting said duct with said means for
supplying gas and with a suction line.
7. A combination according to claim 6, including a filter on and
across said inlet end of the duct.
8. In combination with a bag forming, filling and sealing machine
including a vertical tube having a product passage therein
communicating with product receiving head means, means spaced below
said head means for forming bag sheet material about the tube, seam
sealing means cooperative with the tube below the forming means,
and combination bag sealing, cut-off and pull-down means operative
below the lower discharge end of the tube:
an elongated nozzle member extending downwardly within said tube
passage and operative to discharge flushing gas into the tube
passage for purging atmospheric oxygen from product supplied
through the tube passage into bags formed below said discharge
end;
means for supplying said nozzle member with flushing gas through
the wall area of said tube between said head means and said folding
means;
initial purge gas means communicating with an upper portion of the
tube passage;
an initial purging gas supply line communicating with the upper end
portion of said tube passage below said head means; and
a combination prepurging and gas sampling duct communicating with
the next formed bag below said discharge end.
9. In combination with a bag forming, filling and sealing machine
including a vertical tube having an upper entry end and a lower
discharge end and a product passage therein with the entry end
thereof communicating with head means for delivering product to be
bagged into the passage, means spaced below said head means for
forming bag sheet material about the tube, seam sealing means
cooperative with the tube below the forming means, and combination
bag sealing, cut-off and pull-down means operative below the
discharge end of the passage:
means entering the tube from adjacent to said entry end for
supplying product-flushing gas into said tube passage;
additional means located near the discharge end of said passage for
supplying initial purging gas; and
means for effecting withdrawal through said additional means of
atmosphere monitoring samples of the atmosphere adjacent to the
discharge end of said passage.
10. In combination with a bag forming, filling and sealing machine
including a vertical tube having an upper entry end and a lower
discharge end and a product passage therein with the entry thereof
communicating with head means for delivering product to be bagged
into the passage, means spaced below said head means for forming
bag sheet material about the tube, seam sealing means cooperative
with the tube below the forming means, and combination bag sealing,
cut-off and pull-down means operative below the discharge end of
the passage:
means entering the tube from adjacent to said entry end for
supplying product-flushing gas into said tube passage;
additional means located near said product entry end of the tube
for supplying initial purging gas; and
yet additional means are operative to introduce preflushing gas
near said discharge end of the passage.
11. In combination with a bag forming, filling and sealing machine
including a vertical tube having an upper entry end and a lower
discharge end and a product passage therein with the entry end
thereof communicating with head means for delivering product to be
bagged into the passage, means spaced below said head means for
forming bag sheet material about the tube, seam sealing means
cooperative with the tube below the forming means, and combination
bag sealing, cut-off and pull-down means operative below the
discharge end of the passage:
means entering the tube from adjacent to said entry end for
supplying product-flushing gas into said tube passage;
additional means for supplying initial purging gas at a position
near one of said tube ends; and
means alternatively operable to secure a sample of gas for analysis
adjacent to the discharge end of said passage and to introduce
preflushing gas.
12. In combination with a bag forming, filling and sealing machine
including a vertical tube having an upper entry end and a lower
discharge end and a product passage therein with the entry end
thereof communicating with head means for delivering product to be
bagged into the passage, means spaced below said head means for
forming bag sheet material about the tube, seam sealing means
cooperative with the tube below the forming means, and combination
bag sealing, cut-off and pull-down means operative below the
discharge end of the passage:
means entering the tube from adjacent to said entry end for
supplying product-flushing gas into said tube passage;
additional means for supplying initial purging gas at a position
near one of said tube ends;
control valve means for disconnecting said additional means from
purging gas supply; and
gas analyzing means including a suction pump alternatively
connectable with said additional means by operation of said control
valve means.
Description
This invention relates to gas flushing to replace the atmospheric
oxygen around a product to be enclosed in a sealed package, and is
more particularly concerned with a novel gas flushing system for
vertical form, fill and sealing machines.
Gas flushing packaged products which are detrimentally affected by
atmospheric oxygen trapped within sealed bags can be preserved an
appreciable length of time by substantially flushing the oxygen
from the atmosphere surrounding the products within the sealed
bags. Thus, oxidation and rancidity are at least greatly minimized,
shelf life significantly increased and flavor and aroma are
retained. By way of example and not limitation, coffee, nutmeats,
potato chips and candy are typical examples.
Vacuum packaging has been practiced, but cost of gas flushing is
lower and with gas flushing products with sharp points or abrasive
qualities will not cause damage to the film material of the bags.
Also, in contrast to vacuum packaging which causes the bag or
wrapping material to cling tightly to the product and thus creates
what is best termed a hard package, gas flushing can be controlled
to result in a soft or substantially "pillow" package effect which
is a desirable condition for ready consumer acceptance for at least
some products, and avoids snugging in of the package onto the
product as experienced with vacuum packaging.
Some problems have, however, been experienced in adapting the gas
flushing technique to vertical form, fill and sealing machines,
that is, machines in which packaging material is formed tubularly
about a tube, with the lower end of the tubular packaging material
sealed off and the resulting bag form filled with a product dropped
or moved down thereinto from within the forming tube. Among the
problems has been difficulty in securing adequate flushing during
high speed operation of the machine. Another problem has been that
of assuring adequate flushing of the bag to be filled or already
filled and remaining in communication with the lower end of the
forming and filling tube during a shut-down of the machine so that
it substantially fills with air during the shut-down and the
consequent shutting off of the flushing gas. This is particularly a
factor where the flushing gas is lighter than air, such as
nitrogen.
According to the present invention, the foregoing and other
disadvantages, shortcomings, inefficiencies and problems are
overcome by providing a new and improved method of and apparatus
for replacing the atmospheric oxygen around products with an inert
gas in sealed packages in vertical forming, filling and sealing
machines.
An important object of the present invention is to provide a novel
method of and means for gas flushing for the purpose indicated
utilizing a lighter than air inert flushing gas and excluding
atmospheric air in high speed operation.
Another object of the invention is to provide a new and improved
multi-stage flushing system.
A further object of the invention is to provide a new and improved
gas flushing system including an initial purging to prevent reentry
of air to the product being packaged.
Still another object of the invention is to provide new and
improved combination oxygen analysis and start-up preflushing means
in a flushing system.
A yet further object of the invention is to provide a new and
improved method of and means for flushing in vertical forming,
filling and sealing machines which is readily adaptable for either
original equipment or for installation in existing machines.
Other objects, features and advantages of the invention will be
readily apparent from the following description of a preferred
embodiment thereof, taken in conjunction with the accompanying
drawing, although variations and modifications may be effected
without departing from the spirit and scope of the novel concepts
of the disclosure, and in which:
The drawing is a schematic illustration of a flushing system as
applied to a vertical bag forming, filling and sealing machine.
This invention is especially applicable to vertical forming,
filling and sealing machines of the so-called Zwoyer type
exemplified in U.S. Pat. No. 1,986,422 and an improved version
thereof exemplified in U.S. Pat. No. 3,449,888, and to the extent
necessary for a more complete understanding of details of such a
machine, the disclosures of these patents are incorporated herein
by reference. However, to the extent necessary to a full
understanding of the adaptation of the present invention to such a
bag forming, filling and sealing machine the more or less
schematically illustrated details in the drawing should afford
adequate disclosure herein. To this end, there is shown a vertical
bag forming tube 5 of such a machine including on its upper end
means such as a hopper 7 into and through which product of
generally discrete nature is supplied from a suitable source,
generally in measured bag contents quantities in any preferred
manner. At a suitable distance below the hopper 7, the tube is
equipped with folding arm means 8 operative to receive from a
suitable source sheet-form packaging material 9, such as a suitable
thermoplastic, gas impervious film, and guide the same into tubular
form about the tube 5 with side margins joined in lap seal or fin
seal seam relation. Such material should be possessed of excellent
impermeability characteristics and may comprise laminated films
with polyvinylidene chloride (available commercially as Saran),
foil, or combinations of materials such as polyethylene,
polypropylene, cellophane, and the like with an important
consideration being the film's ability to resist flex cracking,
breaking or pinholing of the barrier material so that, after
flushing, oxygen will not be permitted to migrate into the package,
but the inert gas atmosphere will be reliably retained. Below the
folding arm means 8, the joined margins of the material 9 are
engaged by vertical heat sealing means 10 which may comprise the
usual swinging arm and frame arrangement. Thence, the material
travels downwardly as drawn by vertically reciprocal transverse
sealing die, cut-off and pulldown mechanism 11 which is operative
to heat seal across the formed tube of the material 9 to close the
top of a previously filled bag and to close the bottom of a new bag
12 to be filled immediately under the lower terminal outlet of the
tube 5. As each succeeding bag 12 is sealed, a predetermined
quantity of product to be packaged is dropped down the passage
defined within the forming and filling tube 5 to be received in the
bag which, while the product is dropping thereinto, is being pulled
downwardly until it is two bag lengths below the filling tube
outlet, whereupon the mechanism 11 separates and releases the same
and returns to its upper limit and seals the filled bag, repeating
the cycle.
According to the present invention, the product is, in effect,
"washed" in an inert gas atmosphere while dropping down the passage
within the forming and filling tube 5. To this end, at least one
flushing gas nozzle 13, which is desirably a small diameter tube
duct such as on the order of one-quarter inch outside diameter, is
located to extend downwardly in the passage within the tube 5 with
the lower end of the duct adjacent to the lower end of the tube and
with the upper end of the duct in communication through the wall of
the tube 5 at a suitable point above the folding arm structure 8,
as by means of a connection or fitting 14 with a delivery duct 15
by which inert gas such as nitrogen is conveyed to the nozzle 13.
Depending on requirements, the gas is discharged either from the
lower end of the elongated nozzle 13 or distributed through a
number of holes along the length thereof, as indicated
schematically. This provides an air purging, normal atmosphere
excluding atmosphere within at least the intermediate portion of
the passage within the tube 5 and within the successive bags
12.
Inasmuch as the bag forming and filling machine operates at a
relatively high speed there may be a tendency for air to re-enter
the tube 5 from the top. To afford assurance against such re-entry,
an initial purging of the passage within the tube 5 is desirably
effected upstream from the main flushing effected by means of the
nozzle or distributor 13. Introduction of the inert prepurging gas
through the wall of the tube 5 is by way of a nozzle 17 which may
be, or be on, a nipple or fitting attached to communicate through
the wall of the tube 5 to the interior thereof, at a point above
the member 13, and to which is connected an inert gas delivery duct
18.
Gas is supplied to the delivery ducts 15 and 18 from a suitable
source such as a gas generator or a gas tank 19 which may be
mounted in a cabinet 20 conveniently mounted on a frame member 21
comprising part of the machine frame. From the tank 19 the gas
passes by way of a supply duct 22 to a control valve 23 which may
be integrated with machine operation so as to open when the machine
is operating and to close automatically when the machine is stopped
or shut down. For this purpose the valve 23 may be a solenoid
operated valve assembly. Where the gas source is under high
pressure so that there may be a tendency toward freezing
temperatures on expansion of the gas, especially where CO.sub.2 is
used, and for which the present system is adapted as well as for
nitrogen flushing, a preheater 24 may be suitably mounted in or in
association with the supply duct 22 to bring the gas up to a
temperature which will avoid freezing anywhere in the system. From
the control valve 23, the gas passes to respective flow controllers
25 for each of the delivery lines and each of which has a
respective pressure gauge 27 associated therewith. From the flow
controllers the gas passes on to respective flow meters 28 each of
which has a pressure regulator 29 associated therewith. From the
flow meters 28 the gas passes to the respective delivery ducts 15
and 18.
From time to time or continuously, it is desirable to monitor the
effectiveness of the oxygen flushing or purging action, and herein
this is effected by withdrawing and analyzing a small amount of gas
from within selected or each of the bags 12, as may be preferred.
To this end, gas sampling means are provided comprising a sampling
duct 30 which is desirably located to extend downwardly within the
tube 5, but which may if there is sufficient clearance within the
bag material tube to accommodate the same be located outside and
contiguously parallel with the tube 5 and which duct has its lower
or suction end extending below the discharge end of the tube 5 so
as to project downwardly within the upper portions of the freshly
filled bags 12. Means for filtering the withdrawn gas desirably
comprise a prefilter 31 on and across the entry end of the sampling
duct 30. At its upper end, above the folding device 8, the sampling
duct 30 is connected with a conduit 32 leading to a three-way valve
33 by which the duct 32 can be opened to atmosphere or connected to
a sampling line 34 leading to a filter 35 such as a water filter
and thence to a vacuum pump 37 from which the sample gas is
delivered by continuation of the sampling line to an oxygen
analyzer probe or sensor 38 connected to a readout oxygen analyzer
meter 39 conveniently located on and in respect to the cabinet 20
for ready reading. Through this arrangement it can be readily
determined whether the system is functioning properly to maintain
the residual oxygen content within the packages at a desirable
level, for instance 1 percent. Any adjustments can be made
immediately. As a result, necessity for taking sample packages
somewhere else, such as to a testing laboratory, to analyze for
oxygen level is eliminated, and avoiding lost time and lost
production, but assuring that the bag contents will have as nearly
as practicable uniform low oxygen level optimum for the particular
product being packaged throughout a production run. The internal
pressure within the bags can also be controlled for most desirable
results as to contents cushioning, bag protection, handling
facility, packing space occupied, attractiveness to touch such as
softness, and the like.
After the filling machine has been shut down, and the flushing gas
supply closed off by the valve 23, so much of the flushing gas may
have escaped, or an undesirable amount of air re-entered the tube 5
and the last package formed, that if no means were provided to
reflush the package, it should be discarded as not up to the
standards of the properly flushed and atmosphere conditioned
preceding packages. To obviate such loss of package material and
product at the start-up of the machine after a shut-down, the
sampling duct 30 herein also serves as a prepurge or start-up
flushing nozzle since it extends down into the package which has
been dormant during the shut-down. To this end, a branch duct 40
connects the conduit 32 through the valve 33 with the gas supply
duct 22. By having the duct 40 upstream from the shut-off valve 23,
it is possible to divert sufficient of the flushing gas through the
valve 33 and the conduit 32 into the sampling duct 30 now serving
as a preflush nozzle to purge the package 12 and start the flushing
of the tube 5 before the machine is started. Thereupon, the machine
can be started and the flushing system operated in the normal
manner. By operating the valve 33, the duct 30 can be made to
resume its sampling function before or after startup. Thereby, not
only while the machine is running but also at or before start-up
the amount or percent of bag content oxygen can be monitored and
adjustably controlled.
Although the invention has been disclosed in the FIGURE of the
drawing as applied to a machine having one forming, filling and
sealing tube assembly, it will be clear that the same may be
readily adapted for multiple tube machines wherein each of the
tubes will be equipped with the same gas flushing system
individually or in parallel in the same system with any desirable
modifications to attain uniform results in the parallel but
individually functioning tube assemblies. Both single tube and
multiple tube machines are known in the art.
* * * * *