The present invention pertains in general to an apparatus and method for the modification of atmosphere in the packaging of perishable items, such as food items, for increased longevity. Included herein are methods and process for the monitoring of estimated pressurized gas canisters remaining within a vessel providing pressurized gasses.
The use of modified atmosphere packaging, commonly referred to as “MAP” in the food packaging industry, surrounds the modification of the atmosphere surrounding a product within a package. Modified atmosphere packaging surrounds actively or passively controlling or modifying the atmosphere, commonly for the purpose of extending the shelf life of perishable goods—particularly fresh food items.
Modified atmosphere packaging is used to prevent the growth of microorganisms, post-harvest metabolic activities of intact plant tissues, post-slaughter metabolic activities of animal tissues, deteriorative chemical reactions, including enzyme-catalyzed oxidative browning, oxidation of lipids, chemical changes associated with color degradation, autolysis of fish and loss of nutritive value of foods in general, moisture loss.
A particular practice in the use of modified atmosphere packaging and involves the practice of gas flushing, which is considered as active modified atmosphere packaging. Gas flushing involves the displacement of ambient oxygen with a desired gas or gaseous mixture. In certain scenarios nitrogen, an inert gas, is used to reduce oxidation and the resulting increased rate of spoilage due to oxidation. Oxidation can lead to discoloration, spoilage, flavor deterioration, and texture differences in certain perishable goods. As these effects of oxidation take place, the product is often no longer suitable for sale and results in a loss of potential value for a seller of such products. For such reasons, modified atmosphere packaging has been used in the food packaging industry for decades in food-packing and preparation of food items for sale to consumers.
Common MAP gasses include, but are not limited to nitrogen, carbon dioxide, argon, and oxygen. Under most conditions, Nitrogen is an inert gas and is used to exclude air and, in particular, oxygen from systems to prevent oxidation. It is also used as a balance gas (filler gas) to make up the difference in a gas mixture, to prevent the collapse of packs containing high-moisture and fat-containing foods, caused by the tendency of these foods to absorb carbon dioxide from the atmosphere. For modified atmosphere packaging of dried snack products 100% nitrogen is used to prevent oxidative rancidity.
Carbon dioxide (CO2) inhibits the growth of most aerobic bacteria and molds. Generally speaking, the higher the level of CO2 in the package, the longer the achievable shelf-life. However, CO2 is readily absorbed by fats and water—therefore, most foods will absorb CO2. Excess levels of CO2 in MAP can cause flavor tainting, drip loss and pack collapse. It is important, therefore, that a balance is struck between the commercially desirable shelf-life of a product and the degree to which any negative effects can be tolerated. When CO2 is required to control bacterial and mold growth, a minimum of 20% is recommended.
Argon is a gas with similar properties as nitrogen. It is a chemically inert, tasteless, odorless gas that is heavier than nitrogen and does not affect micro-organisms to any greater degree. It is claimed to inhibit enzymic activities, microbial growth and degradative chemical reactions and can be used in a controlled atmosphere to replace nitrogen in most applications. Its solubility (twice that of nitrogen) and certain molecular characteristics give it special properties for use with vegetables. Under certain conditions, it slows down metabolic reactions and reduces respiration.
Although oxygen is typically removed from a package because it causes oxidative deterioration of foods and is required for the growth of aerobic micro-organisms, it is sometimes desired to maintain a certain level of oxygen for the freshness or color of perishable products. Oxygen is added to packaging in certain scenarios to maintain fresh, natural color (in red meats for example), to maintain respiration in fruits and vegetables, and to inhibit the growth of aerobic organisms such as in some fish and vegetables.
The practice of gas flushing can be performed in a single-stage or two-stage process. A single-stage gas flushing process typically involves injecting a gas mixture into the package such that the gasses replace a majority of the oxygen levels within the package and resulting in a residual oxygen level of between 2-5% within the package. In contrast, a two-stage process first applies a negative pressure to evacuate a majority of air contained within the package prior to replacing it with an injection of a desired gas or gas mixture. Thus, a two-stage MAP process using a similar amount of injected gas mixture typically results in lower residual oxygen levels than a single-stage MAP process. Furthermore, a two-stage MAP process requires less gas to backfill the package than the single-stage MAP process. Alternatively, certain processes employ the use of only a negative pressure to evacuate ambient air from within the package, leaving the packaged item under maintained negative pressure environment.
Regardless of whether vacuum or gas flush packaging is used to create a modified atmosphere, the package itself must provide a barrier to permeation over the expected shelf life, otherwise the beneficial effects of reducing oxygen are lost.
A problem surrounding the use of pressurized gas canisters surrounds the decreasing pressure of gasses held within the canister as the canister is depleted. Depletion of the canister results in lower pressures, and thus lower volumes of gasses dispensed for equivalent dispensing intervals. Accordingly, a dispensing interval from a newly installed gas-filled canister will dispense more gaseous volume than an equivalent length dispensing interval from a half-depleted gas-filled canister.
Although steps have been taken in the field of food packaging to prolong the freshness and salability of perishable products from the grower/producer to the sale to the consumer, there exist few options available to consumers to enable the prolonging of food freshness after sale to the consumer. Therefore, there are intrinsic needs surrounding the storage and prolonging of freshness of perishable products as well as the monitoring of gas content remaining within a partially depleted gas-filled canister in order to provide a consistent and repeatable delivery of gasses in a modified atmosphere packaging solution.
The present invention surrounds a method and apparatus for modified atmosphere packaging (MAP) of products to increase the storage life of perishable products, particularly food products. Certain embodiments provide a compact form-factor which is accessible and usable by hand in a home kitchen or other non-industrial setting, while other embodiments provide an apparatus for use in a commercial setting such as in commercial kitchens and restaurants. It will be appreciated embodiments utilizing methods such as vacuum packaging, a two-stage method of removing air from within a sealed container and back-filling the container with a gas, and gas flushing are within the spirit and scope of the present invention. It will be further appreciated that the use of “vacuum”, and “negative pressure” herein are interchangeable as used in context with the present invention and application thereof.
Existing technologies provide modified atmosphere packaging through the use of form-fill-seal machines which form pouches, or thermoformed trays, from roll-stock which are then filled with product and heat-sealed.
Other existing technologies utilize chamber machines wherein a pouch or tray within a pouch is loaded into a chamber wherein a negative pressure is applied prior to backfilling the chamber with a desired gas and subsequently sealing the pouch.
Other existing technologies use what is commonly referred to as snorkel machines, named for a probe inserted within a large flexible bag containing the product for storage. The snorkel removes existing air prior to backfilling the pouch with a desired gas mixture.
A shortcoming of such technologies is the lack of reusability of the container. Although it is desirable to create form-fill-seal packaging for the sale of products, the general consumer may prefer a reusable and washable container which can be used repeatedly for a variety of perishable products.
A further shortcoming of the above discussed technologies surrounds the space associated with such machines. Such technologies are adapted for industrial processing of goods, and would not be appropriate for use in a home where space is limited.
It is an aspect of certain embodiments of the present invention to provide a container having a reusable base and lid which are configured to interconnect with a device wherein the device modifies the atmosphere within the container through the use of vacuum packaging, applying a vacuum and backfilling with a gas, or gas flushing.
It is an aspect of the present invention to provide a handheld modified atmosphere apparatus which allows a user to use modified atmosphere packaging in a household kitchen without the need of cumbersome or large equipment.
Some existing solutions such as U.S. Patent Publication No 2019/0084749 to Lapidot, filed Mar. 12, 2017 (“Lapidot”)—herein incorporated in its entirety by reference for all purposes—provide a container wherein the container when sealed is placed atop a base, and the base when actuated applies a negative pressure to draw air from the container. Although such technologies provide a consumer level apparatus and method for providing modified atmosphere packaging, such technologies require dedicated countertop space. Furthermore, technologies such as disclosed by Lapidot do not provide the benefit of backfilling of a container with a gas following the vacuum process.
Certain technologies involve the use of a hand-actuated vacuum pump such as disclosed by U.S. Pat. No. 4,889,250 to Beyer (“Beyer”), filed Jun. 30, 1988—incorporated herein in its entirety by reference for all purposes. The hand-actuated pump is connected to one-way valve atop the container and actuated until a sufficient negative pressure exists within the container. Such technologies fail to provide a backfilling of gas to enhance and prolong the freshness of food products placed therein. Similar technologies exist having an electrically actuated pump which once again apply a vacuum within the container but do not backfill with a gas.
Certain existing solutions for the preservation of perishable goods involves the gas flushing of a container using a pressurized canister of gas wherein the gas is sprayed within the container—such as a wine bottle—to replace the ambient air within the container with the gas. Such technologies are often ineffective as they rely on the bulk replacement of ambient gasses and cannot ensure a repeatable low oxygen content without excessive application of the gas thereby limiting the supply of gasses available to the consumer. Furthermore, such embodiments fail to provide a sealing solutions thereby requiring additional equipment and or additional steps for the sealing of a container.
It is an aspect of certain embodiments of the present invention to allow the backfilling of a container with one or more gasses or a mixture thereof. Certain embodiments comprise a plurality of gas-filled canisters wherein the gas-filled canisters are interchangeable and replaceable.
It is an aspect of certain embodiments of the present invention to seal a container by applying a negative relative pressure within the container, wherein the negative relative pressure results in the engagement of the lid and creating a seal between the lid and the container.
It is an aspect of the present invention to provide a handheld modified atmosphere packaging apparatus which interconnects with a storage container such that the apparatus draws a vacuum within the container prior to backfilling the container with an appropriate gas. It is a further aspect that an apparatus of certain embodiments provides the capability to backfill a container with more than one inert gas based upon the perishable product being stored. Certain perishable goods remain usable for longer when different inert gasses are used. Certain perishable goods remain usable longest when a container is backfilled with nitrogen, others with carbon dioxide, others with argon, and others still using a combination thereof. It will be appreciated that the gasses used within the present invention are not limited to nitrogen, argon and carbon dioxide, and the use of any other gasses (inert or otherwise) known to those skilled in the art are within the spirit and scope of the present invention. Furthermore, the utility of the present invention can be applied to containers such as wine containers, baby food containers and baby food makers, and other containers while in keeping with the spirit and scope of the present invention.
It is an aspect of the present invention to monitor and estimate the remaining gasses held within a gas-filled canister such that the amount remaining can be estimated as a pressure, volume, or number of gas deliveries remaining for a particular size container intended for the storage of perishable items.
In certain embodiments, monitoring the delivery of gasses which are dispensed in short bursts while pulling a vacuum. Delivering gasses in short bursts while pulling vacuum at a constant rate provides indications as to how much gas is remaining within the gas-filled canister. By monitoring the gas remaining in the gas-filled canister in this manner, accurate sensors which are often cost prohibitive are unnecessary as the remaining gasses are calculated from trends in pressure within the food storage container.
In certain embodiments, the remaining gas in a gas-filled canister is calculated through the use of force sensors placed between the lobe of the cam and the spring-loaded follower such that the force required to depress the spring-loaded follower until gasses are dispensed is monitored. It will be appreciated by those skilled in the art that forces required to depress the spring-loaded follower will decrease as the pressures within the gas-filled canister decreases. Thus, a user can be alerted to a low-pressure threshold within the gas-filled canister when the forces required to depress the spring-loaded follower reach a predetermined threshold. Alternatively, a user can be alerted to a low-pressure threshold within the gas-filled canister when the forces required to depress the spring-loaded follower reach a predetermined fraction of the forces required to depress the spring-loaded follower when the gas-filled canister was initially installed anew. It will be appreciated that the above method can be accomplished through the installation of a force sensor placed within the actuating electro-mechanical motor. Although force sensors have been described herein as being placed between the lobe of the cam and the spring-loaded follower, it will be appreciated that alternative placements of force sensors to monitor forces required to dispense gasses are within the spirit and scope of the present invention.
In certain embodiments, the remaining gas in a gas-filled canister is calculated through monitoring the reaction force in the electro-mechanical motor used to drive the valve actuator. It will be appreciated that in order to overcome increased resistance, an electro-mechanical motor requires an increased level of electrical current to operate. Thus, the forces required to actuate the cam and thereby depress the spring-actuated follower can be calculated based upon the electrical input required by electro-mechanical motor to depress the spring actuated follower and dispense gasses. Accordingly, when the electrical current needed to dispense gasses drop to a predetermined threshold, a user can be notified of a low-pressure threshold within the gas-filled canister. Alternatively, when the electrical current needed to dispense gasses drop to a predetermined fraction of the current required to depress the dispense gasses when the gas-filled canister was initially installed anew.
In certain embodiments the remaining gas in a gas-filled canister is calculated through monitoring the number of step counts an electro-mechanical motor requires to deflect the spring-loaded follower until gas is dispensed. It will be appreciated by those skilled in the art that electrometrical motors such as stepper motors operate with a predetermined number of motor steps wherein each step equates to a predetermined angular displacement. Thus, the number of motor steps is directly associated with the angular displacement of a motor, and can be further translated to a linear displacement dependent upon the system within which it operates. It will be further appreciated that alternative electro-mechanical motors such as servo motors and step-servos allow the user to operate the motor at known angular displacements. As discussed herein, a “step” is associated with a predetermined angular interval and is not limited to a particular type of electro-mechanical motor. A larger number of motor steps results in a larger orifice for dispensing gas, and a smaller number of motor steps results in a smaller orifice for dispensing gas.
Due to gas flow characteristics, such as choked flow environments, it will be appreciated that the number of motor steps required for the dispensing of gas may not follow a linear progression as the gas within the gas-filled canister is expended. Explanations for such characteristics include a choked flow environment, but are not limited thereto.
Choked flow is a limiting condition where the mass flow will not increase with a further decrease in the downstream pressure environment for a fixed upstream pressure and temperature. For homogeneous fluids, the physical point at which the choking occurs for adiabatic conditions, is when the exit plane velocity is at sonic conditions; i.e., at a Mach number of 1. At choked flow, the mass flow rate can be increased only by increasing density upstream and at the choke point. The mass flow rate in a choked flow environment is independent of the downstream pressure, and depends only on the temperature and pressure and hence the density of the gas on the upstream side of the restriction.
Thus, in certain embodiments of the invention, the number of motor steps required to dispense a predetermined amount of gas over a predetermined timespan are nonlinear. As the gas-filled canister is depleted, the upstream pressure decreases, the choked-flow condition is released, and the system requires a higher number of motor steps to provide the desired amount of gas over a predetermined timespan. Thus, the number of motor steps required to overcome the choked flow environment increases linearly as the gas-filled canister nears the end of its capacity. In certain embodiments it is the monitoring of this linear increase of motor steps which indicates the remaining gasses within the gas-filled canister for dispensing. Accordingly, the system of certain embodiments records the number of motor steps required to dispense predetermined amount of gas over a predetermined amount of time. Each subsequent dispensing process recalls the number of motor steps required in the preceding dispensing of gas.
In certain embodiments, the monitoring of remaining gas within a gas-filled canister can be performed using the combination of linear springs disposed between the pin of a valve-actuator and an extension arm of a cam. Monitoring the number of motor steps required of an electro-mechanical motor. It will be appreciated that when the pressure within the gas-filled canister is high, the spring will compress and require a higher number of motor steps to dispense gasses from the canister. However, as the pressure within the gas-filled canister decreases, the spring is less compressed during the dispensing of gasses, and thus the electro-mechanical motor requires fewer motor steps to dispense gasses from within the gas-filled canister. Therefore, it will be appreciated by one skilled in the art that the monitoring of step count of the electro-mechanical motor can be used to monitor spring compression which directly relates to the gas pressure held within the gas-filled canister.
These and other advantages will be apparent from the disclosure of the inventions contained herein. The above-described embodiments, objectives, and configurations are neither complete nor exhaustive. As will be appreciated, other embodiments of the invention are possible using, alone or in combination, one or more of the features set forth above or described in detail below. Further, this Summary is neither intended nor should it be construed as being representative of the full extent and scope of the present invention. The present invention is set forth in various levels of detail in this Summary, as well as in the attached drawings and the detailed description below, and no limitation as to the scope of the present invention is intended to either the inclusion or non-inclusion of elements, components, etc. in this Summary. Additional aspects of the present invention will become more readily apparent from the detailed description, particularly when taken together with the drawings, and the claims provided herein.
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It will be appreciated to those skilled in the art that common statistical methods of data analysis of deterioration of gas dispensing effects as measured and disclosed above can be used in the above identified example datasets when recording, storing, and analyzing the effect of dispensing gasses in bursts, or tracking the number of motor steps required to dispense gasses.
While various embodiments of the present invention have been described in detail, it is apparent that modifications and alterations of those embodiments will occur to those skilled in the art. However, it is to be expressly understood that such modifications and alterations are within the scope and spirit of the present invention. Further, the inventions described herein are capable of other embodiments and of being practiced or of being carried out in various ways. In addition, it is to be understood that the phraseology and terminology used herein is for the purposes of description and should not be regarded as limiting. The use of “including,” “comprising,” or “adding” and variations thereof herein are meant to encompass the items listed thereafter and equivalents thereof, as well as, additional items.
This application claims the benefit of U.S. Provisional Patent Application 63/048,311 entitled “APPARATUS, SYSTEM, AND METHOD FOR MODIFIED ATMOSPHERE PACKAGING” filed on Jul. 6, 2020, the entire contents of which are incorporated herein by reference in its entirety for all purposes.
Number | Date | Country | |
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63048311 | Jul 2020 | US |