One-piece, double-walled isothermal tank for storing chemicals and food

Abstract

The invention relates to the production of a one-piece, double-walled isothermal tank in two parts, for storing chemical and food products, having a capacity ranging from 50 liters to 40000 liters.

Description

[0001] Single-piece double-walled insulated tank for storing chemicals and food products I – Presentation of the invention Single-piece, insulated, rotomolded, two-part food-grade plastic tanks, equipped with a cover and a threaded manhole between the two walls. Technical field: The invention relates to the manufacture of single-piece, two-part plastic double-walled insulated food tanks using the rotomolding process. An insulator is then injected to ensure maximum resistance of up to +150°C, between the two walls of each single-piece part to ensure thermal insulation against bad weather, particularly high heat and cold waves, and to reinforce the tank against shocks that may result from transport or handling inside storage areas. Assembly is carried out by fitting the two parts together.The fixing and tightening by threaded members and inserts in stainless steel or anchor bolts or helical screw also in stainless steel. The two parts are then welded to ensure the tightness of the single-piece double-walled tank. State of the prior art: The tanks currently used for the transport and storage of food products and products sensitive to temperature variations are either made of single-walled or double-walled stainless steel, and are therefore heavy and expensive and also require the consumption of energy to keep their contents at the required temperature, or housed in suitable spaces at a temperature meeting the storage conditions of their contents, or emptied of their contents as soon as the transport and handling operation is completed, in order to prevent the quality of the product from being affected by the temperature variation.On the other hand, single-walled tanks present risks related to their sensitivity to shocks during movement, and even during handling inside storage areas. In addition, food products transported or stored in plastic tanks currently available on the market are exposed to the risk of contamination by bacteria in the event of storage at low temperatures, due to the material from which the tanks are made, and the lack of special treatment of these materials. These shortcomings constitute a significant limitation to the use of tanks currently available on the market in difficult conditions, and in a changing environment.Double-walled tanks, improperly called double-walled tanks, were designed to prevent leaks that could result from a perforation of the single wall, but the inner wall is made of plastic and then inserted into the outer wall, and the outer wall acts more as a liquid retention tank in case of a leak resulting from a perforation of the inner wall. Another method of manufacturing double-walled tanks consisted of manufacturing the outer tank, then cutting the previously shaped upper part, for the insertion of the inner tank, and then installing the upper part of the outer tank by welding. Such tanks are not isothermal. Furthermore, the assembly of the parts does not use inserts, and the smooth round passages for connections and other additional functions between the walls are not molded directly into the plastic.Contribution of the invention to the resolution of the problems cited: The tanks proposed by the inventor are designed to remedy all the inadequacies cited above, by combining both the solutions proposed each in isolation, and by adding characteristics specific to the present invention.In fact, these tanks are at the same time: • Molded in a single-piece double-walled structure, the two walls being molded simultaneously for the two parts - upper and lower - of the tank, • Made of plastic, and more particularly of polyethylene or other polymers, which are at the same time lighter, easier to transform, and much less expensive than stainless steel, • Isothermal, in the sense that the two walls are separated by a thermal insulator which is injected after molding the two parts, upper and lower, between the two walls, • Shock-resistant, due to the reinforcement on the sides, the quality of the materials used, and the injection of an isothermal product between the two walls, • Equipped with threaded lids in double-walled and single-piece, thus allowing perfect sealing and thermal insulation, in all circumstances.• High-quality insulating foam reinforces both walls and requires shims to maintain the distance between the two walls.

[0002] II - Presentation of the invention: Characteristics of the invention: The characteristics of the invention give it specificities allowing the tanks thus manufactured to be distinguished from those currently available on the market by: - ​​The solidarity of the two walls molded simultaneously in a single piece of polyethylene with a thickness (from 5 to 20 mm), allowing it a high resistance to shock and bad weather, - The added parts serve as molds, and are fixed between the two walls, and are then molded in the polymer without welding, - The inserts, threads, smooth or threaded round passages, are embedded in the insulating foam to allow perfect insulation, - The insulating product reinforces the two polyethylene walls, - The smooth round passages between the two walls constitute a reinforcement and allow good resistance of the two walls, - The assembly of the two parts is done by fitting, tightening and welding.- Thermal insulation, and consequently the good preservation of food products handled or stored in these tanks. This quality predestines the tanks thus manufactured for multiple uses, domestic, industrial and agricultural (transport and preservation of oil, milk, water in homes, rural schools, construction sites in desert areas with high temperatures, refugee camps, etc.), - Prevention against bacteria that can contaminate sensitive food products, - The manufacture of the tanks will be carried out by rotational molding or blow molding or casting or by thermoforming. Raw materials used for the manufacture of the two parts of the tank: The raw materials used are in particular: . Polyethylene, HD Or BD, . Polypropylene, . PVC, . Plastisol PVC, . Polyurethane, . ABS, . Polyester.Raw materials for thermal insulation: 1 PUR and PIR polyurethane foam 2 expanded polystyrene 3 cellulose wadding 4 cellular concrete 5 other products Manufacturing process of the single-piece double-walled insulated tank: The tank is manufactured in the following steps: - Assembly of the added parts in the mold, - Filling with HD polyethylene polymer, - Starting the machine, - Demolding, - Injection of the insulating material (polyurethane foam) and other product, - Assembly by inserts and anchor bolts or helical screw, - Welding (by polyethylene) or other material, - Assembly of accessories (float, taps, piping, relief valves, drain valve and other additional accessories), - Assembly of the threaded cover. Description of figures: - Figure 1 is a schematic sectional view of a single-piece double-walled molded plastic threaded cover. The diameter can vary from 10cm to 70cm.The one-piece double-walled plastic threaded manhole. - Figure 2 is a schematic sectional view showing a smooth cylindrical threaded end passage between the two one-piece walls that is used for fixing accessories (tap, floats, piping, etc.). Diameters may vary. - Figures 3 and 6 are schematic sectional views of threaded metal inserts molded into the polymers fixed in the outer wall used for fixing a metal reinforcement or a transport base if necessary. Thus, the convex part contains a smooth round passage molded into the polymer that adds reinforcement between the two walls so as not to deform the part when tightening. FIG 6: The 2nd part of the one-piece double-walled plastic tank is provided with a threaded metal insert molded into the polymer in the outer part, comprising a smooth passage molded into the polymer between the two walls for the passage of a tightening member.- Figure 4 is a schematic sectional view of a threaded passage through to the side for attaching accessories (drain valve, flange, and other additional functions). - Figure 5 is a schematic sectional view of the feet molded with the outer wall and forming part of it. The number and dimensions of the feet may vary. - Figures 3 and 6 are schematic sectional views also showing the interlocking assembly of the two single-piece double-walled parts using stainless steel bolts and inserts or anchor bolts or helical screws. High-quality welding is carried out for all tanks, in order to ensure their tightness and higher strength. - Figure 7 is a schematic sectional view of the assembly and fixing methods of the two parts of the tank. The assembly is done by vertical or horizontal interlocking or in a mixed method.

Claims

Claims: - CLAIM 1: Manufacturing process by rotational molding or by blowing or casting of double-walled insulated tanks made of two-part plastic, made of food-grade, UV-resistant HDPE. The tanks are equipped with a threaded, one-piece double-walled lid and a threaded manhole. The tanks have a capacity ranging from 50L to 40,000L, and are intended for the storage and transport of chemical and food products sensitive to temperature variations. The dimensions and shapes (vertical, horizontal, rectangular, cylindrical, cubic, octagonal or spherical) are variable. Both parts have threads molded directly into the polymer between the two walls. Inserts are molded into the polymer between the two walls. Smooth and / or threaded passages are also molded into the polymer between the two walls throughout.The tank feet are molded into the outer walls and are independent of the inner walls. Their number and dimensions are variable. The feet stabilize the tank and support the load of the stored products. The injection of isothermal foam between the two walls provides thermal insulation and greater resistance to shocks. Ribs and handling rings can be custom-made if necessary. The two parts are assembled by interlocking the convex and concave elements of the two parts and tightening with plastic or metal threaded members. A threaded cylindrical part is fixed in the lower part of the tank between the two walls for the installation of accessories (drain taps, flanges, etc.). The smooth passages between the walls serve to reinforce the two walls.- CLAIM 2- Manufacture of the single-piece insulated plastic tank according to one of the claims, characterized in that the demolding of the two upper and lower parts begins once the polymer has sufficiently solidified: Unscrewing of the added parts which are integrated into the mold between the two walls: thread, insert holder, smooth and threaded passage from one side to the other. (Fig2). - CLAIM 3- Manufacture of the single-piece insulated plastic tank according to one of the claims, characterized in that the cover and the single-piece double-walled cylindrical plastic manhole with or without thread are molded in the polymer. (Fig 1) - CLAIM 4- Manufacture of the single-piece insulated plastic tank according to one of the claims, characterized in that the smooth cylindrical passage and threaded at both ends, molded between the two walls from one side to the other is fixed below the protruding manhole. (Fig 2) - CLAIM 5 - Manufacture of the single-piece insulated plastic tank according to one of the claims, characterized in that the threaded metal insert No. 1 is molded in the polymer between the two walls fixed in the outer wall. A smooth cylindrical passage molded in the polymer between the two walls from one side to the other in the protruding part.A smooth cylindrical passage molded in the polymer between the two walls right through in the convex part through which the assembly is carried out. The smooth passages in the convex part are mainly used for the passage of the clamping members (Fig 3). - CLAIM 6 - Manufacture of the single-piece insulated plastic tank according to one of the claims, characterized in that the threaded metal insert No. 2 is molded in the polymer between the two walls fixed in the outer wall and a smooth cylindrical passage molded in the polymer between the two walls. A metal insert No. 3 molded in the polymer between the two walls in the concave part. The smooth passages in the assembly area are mainly used for the passage of the clamping members.(Fig 6) - CLAIM-7 Manufacture of the single-piece insulated plastic tank according to one of the claims, characterized in that a smooth or threaded cylindrical plastic passage molded between the two walls is fixed right through between the two walls in the flat or conical part of the tank. (Fig 4) - CLAIM-8 – Manufacture of the single-piece insulated plastic tank according to one of the claims, characterized in that the feet of the tank are integrated directly into the outer wall independent of the inner part between the two walls. (Fig 5). - CLAIM- 9 - Manufacture of the single-piece insulated plastic tank according to one of the claims, characterized in that all the parts molded in the polymer between the two walls (thread, inserts, smooth passage, threaded passage) are embedded in the insulated product. The thickness of the insulating foam between the walls can vary from 2.5 cm to 20 cm. - CLAIM 10- Manufacture of the single-piece insulated plastic tank according to one of the claims, characterized in that the assembly of the two parts (upper, lower) with a double-walled single-piece insulated tank is done by fitting and welding (Fig 7). The tightening is done using inserts and threaded members or anchor bolts or by stainless steel helical screws and welding. All the inserts and the smooth passages between the two walls of the two parts are variable in quantity and dimensions according to the capacities.The fixing and tightening are variable: By vertical interlocking (7-1) and (7-2), By horizontal assembly (7-3), According to a mixed mode (7-4).

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