Apparatus for squeeze packaging butter-like products

A butter-like product is recirculated from a mixing bowl (10) by a recirculating pump (14) until its viscosity is adjusted to the equivalent of 16,000 to 18,000 centipoise at 75.degree. F. The viscosity adjusted butter is pumped through an aerator (22) to a closed holding tank (40). A positive displacement pump (42) recirculates the viscosity adjusted butter from the holding tank, through a recirculating feed line (44) at a preselected pressure, and back to the holding tank. A plurality of packaging machines (C) each include a metering pump (60) which pumps metered amounts of the butter from the recirculating feed line through at least one filling nozzle (62). Sheets of heat-sealable plastic material from rolls (64, 66) are heat sealed (70, 72, 74, 76) into squeeze packets surrounding the metered volumes of butter. A conveyor (100) conveys the filled squeeze packets to a fluid cooling hood (104) in which the squeeze packets are bathed in a cooling fluid, e.g., nitrogen, before the packaged butter can be adversely affected by residual heat from the heat seals.

The present invention pertains to the art of food processing and more 
particularly to the preparation of foodstuffs for filling squeeze packets. 
The invention finds particular application in the production of 
butter-filled squeeze packets and will be described with particular 
reference thereto. It is to be appreciated, however, that the invention is 
also applicable to filling squeeze packets with other foodstuffs which are 
damaged by heat, such as margarine, shortening and grease products, peanut 
butter, cheese spreads, other shortening or grease-containing products, 
and the like. 
Heretofore, various condiments, such as mayonnaise, mustard, honey, relish, 
and others, have been available in single serving squeeze packets. In a 
conventional packaging system, each packaging machine has an attached 
supply hopper from which the product is metered into the squeeze packets. 
A plurality of air powered pumps disposed in a common open vat each 
maintain a corresponding hopper filled. The squeeze packets are commonly 
fashioned of two rectangular sheets of flexible plastic material generally 
about an inch to an inch and a half by three or four inches. The packets 
are heat sealed around their periphery to define a condiment-holding, 
heat-sealed squeeze packet. Of the many condiments available in squeeze 
packets, butter is conspicously absent. 
Individual servings of butter are not commonly available in squeeze 
packets. Rather, slices or patties of butter are normally individually 
paper or foil wrapped, packaged in stiff plastic containers with peel-off 
tops, or the like. These types of containers require a knife to spread the 
contents. By distinction, the contents of squeeze packets can be spread 
directly. The physical properties of butter have required that it be 
packaged in these other types of packages rather than squeeze packets. 
Butter is relatively hard or stiff in its normal, crystalline state. 
Although it is recognized that butter can be made liquid by increasing the 
temperature, it is generally considered undesirable to do so because 
elevated temperatures permanently alter the physical properties of butter. 
Specifically, butter is an emulsion which breaks down or becomes clarified 
at elevated temperatures. Once the emulsion is broken, the butter will not 
set or recrystallize into the same physical structure. Rather, it will 
have a different color, texture, consistency, and the like, creating a 
different, less desirable appearance and flavor. 
Further, squeeze packets are normally heat sealed at temperatures which are 
sufficient to soften plastic sheet material, e.g., 200.degree. F. to 
300.degree. F. The residual heat in the heat sealed plastic is sufficient 
to cause the butter emulsion to be broken. Specifically, butter adjacent 
the heat seal tends to turn a darker yellow color and change texture and 
consistency creating a different visual appearance often taken for 
spoilage. 
The prior art individual serving butter packages have been relatively 
expensive and are relatively easily damaged in handling and shipment. The 
packaging machines for producing the prior art butter individual serving 
packages tend to run relatively slowly and the packaging operation tends 
to be relatively labor intensive. 
The present invention provides a new and improved processing method which 
overcomes the above-referenced problems and others to provide for the 
production of butter and like foodstuff filled squeeze packets. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, there is provided an apparatus 
for packaging a product which is damagable by heat in heat-sealed squeeze 
packets. A viscosity adjusting means adjusts the viscosity of the product 
to about 16,000 to 18,000 centipoise at 75.degree. F. or the equivalent. A 
pump means selectively pumps preselected volumes of the product to at 
least one filling nozzle. A sheet feeding means feeds sheets of a heat 
sealable material adjacent opposite sides of the filling nozzle. A heat 
sealing means heat seals the sheets into an open, generally U-shaped 
pocket partially surrounding each filling nozzle. After the pump means 
pumps the preselected volume of product into the open pocket, the heat 
sealing means heat seals the open pocket into a closed pocket surrounding 
the preselected product volume forming a filled squeeze packet. A cooling 
means is disposed contiguous to the filling nozzle to bath the filled 
squeeze packet in a cooling fluid such that a cooling fluid withdraws heat 
from the heat-sealed sheets before the product is damaged by the residual 
heat therein. 
In accordance with a more limited aspect of the invention, the product is 
butter. 
In accordance with another more limited aspect of the invention, the fluid 
cooling means baths the heat-sealed packets in a bath of nitrogen. 
A primary advantage of the present invention is that it enables squeeze 
packets to be filled with butter and other heat damagable foodstuffs. 
Another advantage of the present invention is that it packages butter 
relatively quickly and efficiently. 
Yet another advantage of the present invention is that it enables butter to 
be packaged in relatively durable and easily handled individual serving 
packets. 
Still further advantages of the present invention will become apparent to 
others upon reading and understanding the following detailed description 
of the preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Butter is an emulsion of fat, oil, water and solids. The emulsion is solid 
or crystallized at room temperature and below. Just below normal body 
temperature, the emulsion breaks down or separates, releasing the fat and 
oil components to provide the recognizable butter taste. In the preferred 
embodiment, butter is the product to be packaged. However, other similar 
products, such as margarine, are packagable with the present method and 
apparatus. In margarine, the exact emulsion and its properties vary. 
However, the margarine emulsion is commonly selected to imitate the 
characteristics of butter closely. Other emulsions of fat and water such 
as shortenings, peanut butter, cheese spread, and the like, can exhibit 
analogous properties. 
With reference to FIG. 1, the packaging apparatus includes a viscosity 
adjusting means A for adjusting the viscosity of the butter or other heat 
damagable product to an appropriate viscosity for packaging. In the 
preferred embodiment, the packaging viscosity is in the range of 16,000 to 
18,000 centipoise at 75.degree. F., or the equivalent. A feed and 
transporting system B circulates the product with the packaging viscosity 
to a plurality of packaging machines or means C. Each packaging means 
packages preselected volumes of the product in heat-sealed packets. A 
cooling means D cools each heat-sealed packet to remove the residual heat 
from the heat seal before the product is damaged. 
In the preferred embodiment, the viscosity adjusting means A includes a 
jacketed mixing bowl or kettle 10 which receives blocks of room 
temperature product. Room temperature is considered to be in the range or 
about 65.degree. F. to 85.degree. F., with 75.degree. F. being preferred. 
As a first step in the viscosity adjusting process, a plurality of paddles 
12 rotate to break up the blocks and render the product generally uniform. 
A recirculating pump 14 pumps butter from the bottom of the mixing bowl 
through a recirculation line 16 and back in the top of the mixing bowl. 
The recirculation breaks up the butter further and renders it relatively 
uniform. Further, the recirculation tends to reduce the viscosity of the 
product. 
Further viscosity adjustment is provided by passing hot or cold fluids 
through a jacket 18 of the mixing bowl. The viscosity is reduced by 
passing a burst of steam through the jacket followed by cold water to 
remove excess heat. The steam burst should be sufficiently short that the 
heat transfer through the kettle does not heat the product to the 
temperature which irreversibly damages the product. 
When the product viscosity has been adjusted to 16,000 to 18,000 
centerpoise at room temperature, a diverter valve 20 diverts the product 
from the recirculation path to an aerator or whipper 22. The aerator or 
whipper 22 adjusts the viscosity by injecting and mixing a gas into the 
butter. In the preferred embodiment, the gas is gaseous nitrogen from a 
nitrogen source 24 which is regulated by regulator valve 26. A typical 
butter aerator or whipper consists of a spool disposed within a tubular 
line such that the aerator is essentially a tube within a tube. The spool 
includes contracted regions and flanges and a plurality of nitrogen 
expelling orifices. As the butter passes through the aerator, the surface 
projections and constrictions as well as the injected nitrogen whip the 
butter. The degree of whipping can be adjusted by adjusting the amount of 
nitrogen injected, the butter pumping rate, and the like. 
It is important that the temperature of the butter be maintained close to 
room temperature. At temperatures above 92.degree. F., the butter 
irreversibly breaks down, degrading its quality. Other heat damagable 
products also have quality degradation temperatures at which they degrade 
noticably. If the product temperature becomes too low, the packaging 
machines will not function properly. To maintain the proper temperature, a 
heat adjusting jacket 28 is provided around the aerator to add or remove 
heat as may be required. 
A pressure regulator 30 maintains the whipped butter at a preselected 
elevated pressure which helps to maintain the nitrogen in suspension in 
the butter. The whipped butter is passed to the feed system B. Optionally, 
a bypass line 32 may bypass the aerator 22 to provide non-whipped product 
to the feed system for packaging. 
The room temperature butter with its viscosity adjusted as is appropriate 
to the packaging means C is received by the feed system B, more 
specifically, in a closed holding tank 40. It is a property of butter that 
it will continue to hold the adjusted viscosity for about a half hour or 
so without the application of additional heat. Thereafter, 
recrystallization tends to raise the viscosity and render it too stiff for 
the packaging machinery. 
The feed and transporting system B includes a positive displacement pump 42 
which withdraws product of the packaging viscosity from the holding tank 
40 and recirculates it through a recirculating feed line 44 back into the 
top of the holding tank. A pressure regulating valve 46 and a pressure 
gauge 48 are disposed near the end of the recirculating feed line to 
maintain a preselected pressure therein. In the preferred embodiment, the 
preselected pressure is in the range of 20 to 30 pounds per square inch. A 
plurality of taps, each controlled by a shutoff valve 50 feed the 
packaging viscosity product from the recirculating feed line 44 to one of 
the packaging machines C. A plurality of check valves 52 are disposed in 
the recirculating feed line between the packaging machine taps to assure 
unidirectional circulation of the product. 
Each of the packaging means C includes a metering means 60 such as a slug 
pump which meters or pumps a preselected volume of product in each stroke 
from the recirculating line 44 to a filling nozzle 62. In the preferred 
embodiment, the slug pump has a plurality of pistons to pump a metered 
volume of the butter to each of a plurality of filling nozzles 62. Rolls 
64 and 66 of a heat-sealable material, such as polyethylene, polyester, 
and the like, each feed a flat sheet of the heat-sealable material to 
either side of the filling nozzle 62. A heat sealing means heat seals the 
sheets into an open, generally U-shaped pocket partially surrounding each 
filling nozzle. More particularly, verticlly extending heat sealing means 
70 and 72 come together in coordination to either side of the filling 
nozzle to heat the sides of a squeeze packet together. Concurrently, 
transverse heat sealing means 74 and 76 come together to close the bottom 
of the pocket to be filled, thus forming a generally U-shaped, open pocket 
partially surrounding each filling tube. After the pumping means 60 pumps 
the preselected volume of product into the open pocket, the heat-sealable 
sheets and the open pocket advance the length of one pocket. As the heat 
sealing means forms the next generally U-shaped pocket, the transverse 
heat sealing means 74 and 76 simultaneously heat seal the top of the 
just-filled pocket, thus completing a squeeze packet. Concurrently, a 
cutter 78 cuts the filled squeeze packets 60 apart allowing them to drop 
from the packaging apparatus C. 
With reference to FIG. 2, each heat-sealed squeeze packet 80 is heat sealed 
along its vertical or side edges 82 and 84, along its base edge 86, and 
along its top edge 88. When the package is held vertically during the heat 
sealing and cutting steps, the butter settles below the top edge of the 
packet such that its upper surface 90 is disposed an half inch or more 
from the upper heat seal 88. Accordingly, sealing the top edge 88 of the 
packet normally does not adversely affect the packaged butter until the 
package is tipped horizontally and the butter is allowed to contact it. 
However, the heat seals along the other three sides 82, 84, and 86 have a 
residual heat buildup therein. The plastic material holds the heat for a 
sufficiently long time that even after the cutting step, there is still a 
large amount of heat in the heat seals. Gradually, this residual heat is 
absorbed by the packaged product. Because the heat sealing generally takes 
place in a temperature range of 200.degree.-300.degree. F., there is 
sufficient residual heat to break down the butter irreversibly or clarify 
it. Even butter which does not break down discolors around the edges from 
the heat to a darker yellow. However, a small amount of time is required 
for this heat to be conveyed into the butter. The packaging means cycles, 
i.e., fills and seals a squeeze packet, more frequently than once a 
second. In the preferred embodiment, the packaging means cycles several 
times a second. Thus, the heat-sealed squeeze packets are filled and cut 
and the filling process completed in about a second or less. This time is 
insufficient for the heat to travel from the heat seals into the butter 
and discolor it or adversely affect it. 
The cooling means D is disposed closely contiguous to the packaging means 
B. Particularly, the cooling means is immediately downstream from the 
filling nozzle and the heat sealing means to withdraw the residual heat 
from the heat seals before it adversely affects the packaged butter. The 
cooling means includes a conveyor 100 such as a metal mesh conveyor. The 
metal mesh conveyor has relatively good heat transfer properties and 
starts the process of withdrawing heat from the package. Optionally, the 
conveyor may be cooled with a water bath or the like during its return 
travel to accentuate its cooling role. 
The conveyor 100 conveys the heat-sealed packets into a fluid cooling means 
102 which baths the filled squeeze packets in a cooling fluid which 
removes the residual heat from the heat seals before the butter is damaged 
by the heat therein. In the preferred embodiment, the fluid cooling means 
102 includes a hood 104 under which the squeeze packets pass. A plurality 
of fluid injecting nozzles 106 discharge cooling fluid over and around the 
squeeze packets. In the preferred embodiment, the fluid injecting nozzles 
106 cause a compressed gas, preferrably nitrogen, to undergo a phase 
change from a liquid to a gaseous state. As the gas undergoes the phase 
change and expansion, it absorbs large amounts of heat, sufficient to 
lower and maintain the pressure under the hood many degrees below 
0.degree. F. The fluid nozzles 106 are connected by a manifold 108 and a 
pressure regulator valve 110 with a compressed nitrogen cylinder 112 or 
other source of compressed inert gas. At the end of the conveyor, the 
cooled squeeze packets are discharged into a packing box 114 or other 
receiver. 
The invention has been described with reference to the preferred 
embodiment. Obviously, modifications and alterations will occur to others 
upon reading and understanding the preceding detailed description of the 
preferred embodiment. It is intended that the invention be construed as 
including all such alterations and modifications and so far as they come 
within the scope of the appended claims or the equivalents thereof.