Patent Application
20190135488
The present invention relates to a plastic tank for the storage and transport of bulk material, such as solids, liquids, or semi-liquids, and in particular to an improved plastic tank for the storage and transport of bulk material with a 400 liters capacity, which is molded in one-piece using an injection molding process, and is reusable and can be nested within another plastic tank.
Up-to-date, plastic drums or plastic bulk containers have been used for bulk transportation and storage of agricultural products, foods in brine or syrup (pickled vegetables, fruit compote, etc.) or liquid foods (oil, wine etc.). Both said types of containers are manufactured using blow molding technology.
Metal drums have also been used as bulk containers, either welded-top type, used exclusively for liquids (e.g. oils), or open-top type with an additional plastic bag (aseptic bag) inside. Due to their shape, said conventional containers (cylindrical plastic drums and cuboid bulk containers) cannot be nested within each other and thus, in most cases they cannot be reused, as the cost of return shipping, when empty, is particularly high, due to the fact that, when empty they take up the same space as when filled. In fact, the cost of reuse is actually higher than the purchasing cost of a new drum or bulk container. Therefore, hundreds of millions of plastic and metal drums are manufactured per year to be used just once. Unfortunately, today most drums are designed to be used once, then discarded.
In case, said conventional plastic containers do not be returned for re-use, the users have to pay for their destruction and disposal in accordance to the national recycling taxes regulations. For this purpose, big companies have installed specific facilities for destroying and disposing these materials. Each year a growing volume of plastic waste is produced by dirty, disposed bulk containers. The practice of no reuse of the plastic containers leads to the utilization of inferior raw materials (regenerated plastic) by bulk packaging manufacturers. As a result, the plastic containers have a very short expected lifespan.
Moreover, the handling of drums demands specific tools and significant physical strength. The drums have to be placed on low-cost, unsanitary wooden pallets, in order to be handled using a forklift. This fact increases significantly the time demanded for loading and unloading (logistics time). If plastic pallets which meet the sanitation standards are used instead, cost and accident hazard both rise dramatically, given that the surface of plastic pallets is smooth and slippery. Therefore, additional packaging materials (stretch film, belts) are used to secure the load, further increasing the initial cost.
Furthermore, bulk containers can only be used for bulk liquid products, since the filling and emptying process is executed through a small opening (max 2 inch), and the cleaning of said containers is difficult and expensive.
Further, most of said bulk containers are mounted on a wooden pallet that does not meet the hygiene requirements for food industries, and in order to ensure stability and security, they are housed within an iron cage.
The users of metal drums and bulk containers face many issues during cleaning and due to material oxidization as well, which creates contamination problems, making these two types of containers unfit for reuse with food products.
Both drums and bulk containers take up too much storage space. Manufactured from raw materials of inferior quality, they are deficient in strength and not stackable. Thus, companies have to invest in building additional storage facilities, as the same space is taken up by drums and bulk containers, when filled as well as when empty, since they cannot be nested within each other.
The currently increasing demand for safer and more sustainable packaging materials requires the existence of a bulk packaging container that is returnable and reusable for long term. Specifically in the field of food industry, the standards for safety and hygiene are now stricter and the existing solutions do not fully meet the sanitation requirements.
The use of plastic drums or bulk containers add a high cost for packaging purposes, due to the fact that said conventional containers are not returnable and reusable, and further, that is also a problem for companies which care about reducing CO2 emissions and improving their energy footprint. Vast amounts of petroleum are used each year for the production of plastic and transportation of these bulk packaging materials.
Thus, there still exists a need for an improved bulk container for solids, liquids or semi-liquids, which is watertight, reusable, returnable and easy to handle.
It is, therefore, an object of the present invention to provide an improved plastic tank for the storage and transport of bulk material, such as solids, liquids or semi-liquids, which overcomes the deficiencies of the prior art and provides a plastic tank that can be efficiently transported and stored, when empty.
Moreover, it is another object of the present invention to provide an improved plastic tank, which is molded in one piece with adequate strength, so as it is stackable even when filled and leak-resistant.
In accordance with the above objects of the present invention, a plastic tank for the storage and transport of bulk material, such as solids, liquids or semi-liquids is provided, comprising
a) a main body (1) having a rectangular base (18) with integrally built-in at least four legs (20), four sidewalls (11a, 11b, 12a, 12b) extending in trapezoid shape upwardly and outwardly from the base (18), and defining a rectangular top opening, which forms a body-rim (15) provided with a projecting edge (16) along the periphery of the body-rim (15), wherein said base (18) with said at least four legs (20) have a pallet type configuration, the bottom surface of the base (18) is externally reinforced with base ribs (19) molded in both directions, and said four sidewalls (11a, 11b, 12a, 12b) are provided with webbed ribs (13) molded across their external surface so as to provide great strength and stability to the main body (1);
b) a main rectangular lid (2) having a top surface, a bottom surface, an eccentric round opening (30) for filling up the tank and a main-lid rim (31) with a main-lid groove (14) along the periphery of said main rectangular lid (2) and a main-lid rubber gasket (71) that fits in said main-lid groove (14), wherein said main lid (2) is attached to the open top of the main body (1) and is closed with safety-lock pins (8) secured along the body-rim (15) of said main lid (2) and the main-lid rim (31) of the main rectangular lid (2), said safety-lock pins (8) in conjunction with the main-lid rubber gasket (71) provide a watertight sealing to the tank, the bottom surface of the main lid (2) comprises webbed ribs (36) molded in both directions so as to control internal forces when the tank is loaded, the top surface of the main lid (2) comprises feet sockets (27) molded on the four corners so as to receive the feet of the upper tank during stacking, and the round opening (30) is provided with a round lid groove (34) around the its periphery to hold a round-lid rubber gasket (72) around the periphery of the secondary round lid (3) for a watertight seal when closed; and
c) a secondary round lid (3) that fits in the eccentric round opening (30) of the main rectangular lid (2) comprising a vent hole (22) sealed with a vent cap with a gas extraction valve (4) to facilitate the outflow of the fermentation gases formed inside the tank, wherein said base (18) with the at least four legs (20) and the four sidewalls (11a, 11b, 12a, 12b) are made of plastic molded in one-piece, one of the sidewalls of the main body (1) adjacent to the base (18) of the main body (1) of the tank comprises a discharge opening (17) that can be equipped with a drainage valve (50) in order to empty the liquids inside the tank, and said at least four legs (20) of the base surface further comprise detachable and replaceable feet plugs (5) suitable to be plugged in said legs (20). Further preferred embodiments of the present invention are defined in dependent claims 2 to 16.
Other objects and advantages of the present invention will become apparent to those skilled in the art in view of the following detailed description.
The present invention will become better understood with reference to the accompanying drawings, which show preferred embodiments in accordance with the present invention without limiting the scope or spirit of the invention
Referring to
Referring to
The ribs (13) extend symmetrically over all four sidewalls of the main body (1) of the plastic tank. Their length, number, thickness and placement has been standardized following a number of structural studies and tests with various types of plastic (construction analysis, flow mold analysis) to guarantee firmness and durability in stacking conditions.
The ribs (13) transform the main body (1) of the plastic tank into a safety cage. Pressure and weight forces are transferred across the ribs (13) from the main rectangular lid (2) (see
The four sidewalls at their corners are provided with particularly designed corner-ribs (6), which extend from directly below the main body-rim (15) of the top opening, across its four corners, to the base (18). These protruding corner-ribs (6) provide the desired distance between the empty tanks, when nested (see
The body-rim (15) of the main body (1) is provided with a projecting edge (16) is along the periphery of said body-rim (15) corresponding to a main-lid groove (14) along the periphery of the main rectangular lid (2) (see
The front sidewall (11a) of the main body (1) at its lowest part adjacent to the base (18) of the plastic tank comprises a discharge opening (17) with a diameter such as a 2 inch, for the optional application of a plastic or metal external drainage valve (50) in order to empty the liquids inside the plastic tank.
The base (18) with the at least four legs (20) of the main body (1) has a pallet type configuration and its dimensions are about 800 mm×600 mm×190 mm. Said dimensions comply with international logistics standards and guarantee maximum stability during handling with the use of a forklift. The bottom of the base (18) is externally reinforced with symmetrical base ribs (19) in both directions, which provide strength and sturdiness during lifting. The base (18) can support the weight of at least two full tanks dynamically stacked (
Alternatively, at least two one-piece traverses (10) (see
The plastic tank and all its components of the present invention are made of food grade High-density polyethylene (HDPE) and is molded in one-piece by using one-piece injection molding method, which provides a one-piece tank embodying the base (18) with the at least four legs (20), thus maximizing security and durability. The clamping force in the injection process for flowing HDPE is 5,000 tons. All parts of the tank can be made in one of 7 different colors or even transparent. Coloring and transparency is achieved by mixing additives with HDPE during injection process. The exact procedure as well as the materials and additives used are matters of disclosure. Generally, it is about mixing HDPE with additives and catalysts creating master-batches according to a disclosed polymer formula, to achieve the desired firmness, flexibility and durability of the tank.
The use of special polypropylene catalysts allows the tank to retain its physicochemical characteristics, standard dimensions and stacking stability in a temperature range of −20° Celsius up to 60° Celsius. This parameter of the present invention is critical for the food industry especially for products that are stored outdoors or require refrigeration. All interior surfaces of the body (1) have a smooth and round-cornered finish (25). On the inside lowest part of the front side (11a) there is a bottom discharge opening (17) of 2 inch for emptying liquids. Additionally, there is a filter socket (64) (
Referring to
Further, on the top surface of the main rectangular lid (2), it is provided a rainwater drain-off hole (29) useful for outdoor storage conditions. Stagnant water on the main rectangular lid (2) could become contaminated with harmful organisms affecting the contents of the tank. The round opening (30) wherein a secondary round lid (3) (
The main-lid rim (31) comprises key-shaped holes (32) e.g. twenty two key-shaped holes, wherein the corresponding safety-lock pins (8) e.g. twenty two safety-lock pins, lock through. The main-lid rim (31) has main-lid ribs (33) molded on its top surface, which provide rigidness and strength, particularly when tanks are stacked one on top of the other.
The bottom surface of the main rectangular lid (2) is reinforced with webbed ribs (36) in both directions, which provide maximum sturdiness and stability, especially when the tanks are stacked. The webbed ribs (36) have a breakwater attribute, controlling internal forces when the tank is loaded with liquid products. The bottom surface of the main rectangular lid (2) further comprises screen-ribs (37) that are elongated and differentially shaped than the webbed ribs (36). Said screen-ribs (37) put downward pressure on the internal rectangular retaining screen (60) (
Referring to
The bottom surface of the secondary round lid (3) is designed with a protruding bottom (44) to enter the main body (1) of the tank and press down upon the round screen (70), which keeps solids into liquids (e.g. pickled vegetables), despite levitation. Further, on the bottom surface of the secondary round lid (3), there are provided six sealing ridges (23) that secure it onto the main rectangular lid (2) (
Referring to
Referring to
Following various studies and tests, it has been found that in order to seal the tank 100% watertight, twenty two safety-lock pins (8) should be used pins, each locked in a key shaped holes (32) molded on every second main-lid rib (33) along the periphery of the main-lid rim (31). These safety-lock pins (8), made of polyamide for maximum durability, combined with the main-lid rubber gasket (71), which nests in the main lid groove (14), provide absolute and secure sealing even when tanks are stacked or moving. Moreover, the vent cap with the gas extraction valve (4) comprises a gas valve cover (56), to prevent entrance of undesired particles through the vent hole (22) and can also be secured against unauthorized access to the contents of the tank, with the use of a plastic or metal safety seal through its safety cover hole (57). Below the vent cap (4) an elastic membrane (26) on the gas-extraction valve (58) opens automatically to release fermentation gases formed inside the tank, especially in high temperature conditions. The function of the gas extraction valve (58) is triggered by interior pressure forces when said forces are more than about 37 psi. When the material of the tank are chemically inactive, the gas extraction valve (58) remains sealed. The vent cap with gas extraction valve (4) is screwed onto the secondary round lid (3) with a rightward half turn move. The sealing ridges (52) lock in the vent hole (22) of the secondary round lid (3) and is sealed with the vent-cap rubber gasket (73) fitted into the vent-hole groove (42).
Referring to
Referring to
This feature enables the user to check, control and fill the tank with liquids or semi-liquids, without lifting the hole tank and opening the main rectangular lid (2), decreasing dramatically contamination risk, because the content of the tank doesn't have extended contact with outside air. The turtle-shell like design of the tank allows a three-tank static stacking (67) and a two-tank dynamic stacking (68).
Referring to
The plastic tank is made watertight with two lids of different sizes, a main rectangular lid and a secondary round lid, which ensure quick and easy access for filling up, quality control and overall product safety. All parts of the tank are made from food grade HDPE and fully meet sanitation standards. The especially composed raw materials used in the production process, the manufacturing technology (high pressure injection molding) and the structural design of the tank (“turtle-shell”) make it stackable when full and enable steady transportation with no leakage. The conical design of the tank enables to be nested, so that empty tanks can be placed one inside the other and be safely returned to be reused. Furthermore, a drain valve facilitates liquid content removal. A vent cap with a one-way operating gas extraction valve enables the discharge of fermentation gases. As a result of manufacturing materials and production technology, the tank has an expected lifespan of 10 years and it can be efficiently reused. Due to its shape and construction, the tank can be handled effortlessly and securely using all current industrial transportation means (forklift, pallet dumper etc.).
The specifically calculated dimensions of the tank enable secure delivery with all standardized transportation means (trucks, sea containers).
While the present invention has been described with respect to the particular embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made in the invention without departing from the spirit and scope thereof, as defined in the appended claims.
