UA5522U - Metal multipurpose cover for cans - Google Patents

Abstract

Metal multipurpose cover for food cans consists of strand, one or several toroidal bloated rings, mantle ring and intermediate annular surfaces. Intermediate annular surfaces are located gradually relative to the mantle ring inside the can and fixed to the bloated rings in such a manner, that the internal circle of bloated ring is located under external circle for the value equal to 5... 15 thicknesses of tin, and the centers of circles, which form toroidal surface of corrugation, are located higher than the mantle ring or intermediate annular surfaces for the value equal to 0... 15 thicknesses of tin.

Description

The useful model refers to the food industry, namely to the clogging of canned cylindrical glass and containers made of thin material, for example, from tin or other sheet materials and intended for pasteurization (sterilization) of canned goods.

The design of lids for metal cans and glass containers must take into account the technological operations of processing raw materials for canned goods, the temperature of packaging and sterilization, prior to capping. So, for example, when using a PP cap ("twist-off"), it must be taken into account whether it is used as a hermetic or as a "breathing" closure used by equipment for sterilization (pasteurization). If it is used during pasteurization, then the excess pressure at which it depressurizes depends on the thickness of the tin, the number of fixing points and the relief profile of the lid.

After the product has cooled, the pressure in the can leads to a drop in external pressure, and therefore the effort required to open the can depends on the amount of "vacuum" and the relief profile of the lid. application Me20031212408 dated 12.25.2003.

For the container, which is hermetically sealed throughout the process of production and sale of canned goods, the pressure is determined by |8V| type of raw material, pre-treatment, use of exhaust, filling factor, packaging and sterilization temperatures, etc.

During cooling, the reduced pressure in the container depends mainly on the method of packaging, the type of product and the ambient temperature. So, for example, during hot bottling of homogeneous products, the pressure at the moment of capping is equal to atmospheric pressure (when capping under normal conditions), and during cooling, due to the high temperature of bottling (85...95"C), the pressure in the container is reduced (0.09 MPa). leads to vacuum deformation of metal cans (bodies and lids).

Regardless of the type of container, during sterilization due to the internal excess pressure in the jar, the lid bends and the increase in the volume of AM is determined by the dependence on (|З

АМаклвВ:оо, where k - depends on the design of the cover profile (for a flat cover with small deflections k-1/3); A - the radius of the neck of the can; со - deflection of the lid in the center (the value of со is determined by calculation, method or experimentally).

The change in the volume of the can, and, therefore, the pressure in the sub-lid space for a cylindrical can is determined by the dependence -pk (3)

M N where n is the number of lids (ends) of the jar (n--1; 2); H - the height of the can.

From the analysis (1), it follows that in order to reduce the value of a possible jump-like increase in pressure (it depends on the topography of the ends), it is necessary to reduce the deflection of the cover Fo.

Analyzing the stress-strain state of round plates or membranes (flat or corrugated), the authors (1, 2, З|) showed that in the strip of the plate adjacent to the contour (at the place of attachment), the circumferential stresses si in the middle plane are compressive and the edge strip performs the role of a reinforcing rib.At the same time, when the pressure, and therefore the deflection, reach certain critical values, the membrane (plate) loses its stability and folds form along its perimeter.

After carrying out some transformations, the dependence for determining the circumferential stresses in relation to the design of the can with (1, 2| will take the form o; o4E|---|, (2) where sa is the coefficient due to the condition of the plate or corrugated membrane resting; E is the modulus of elasticity of the cover material.

Therefore, with the known design of the container, to reduce the possible occurrence of folds, it is necessary to take into account the conditions of fixing the lid to the neck of the can, and to reduce the value of si, it is necessary to reduce the deflection oo.

Metal containers (GOST 5981-88) are used for canned goods, juices and drinks. Lids (one or two - for collapsible cans, which are called ends), are rolled to the cylindrical body with the formation of a double seam. At the end, concentric corrugations are applied, which form the relief profile of the lid and are designed to compensate for excess pressure in the jar during sterilization. The deformation of the ends should be within the limits of the elasticity of the relief and, upon cooling, restore its original shape without residual deformations. The quality of canned products during storage is also judged by the condition of the ends.

The most common types of defects during the sterilization of canned goods in metal containers are the formation of folds at the ends at the point where they are rolled to the body of the can, the so-called "birds", and the appearance of residual irreversible deformation of the ends, one of the types of which is the flapping ends. To eliminate these types of defects, standard relief profiles on the lid and end, as well as various reliefs developed by the authors (4, 5, 6), are recommended. Analyzing these recommendations, we note that they recommend the toroidal shape of the corrugation (cotton rings) and all the corrugations are directed with their convexity outwards and only in one work (U, France| it is suggested to direct the bombage rings with their convexity inward, followed by a series of stepped transitions to the center of the lid. This is the construction of the relief increases its stability.

Summarizing the above, it should be noted that all authors consider the ends as an independent structural element, and not the joint operation of the lid with the body of the jar. As follows from dependence (2), the conditions for securing the membrane (plate) are of great importance. This is also confirmed by the fact that for the SKO cover (cap type

And that is exposed to the same loads during sterilization in autoclaves as a metal container, which has a flat profile, as well as less adhesion to the crown of the can, such a type of irreversible deformation as "birds" and "flappers" is not characteristic. The essential difference in this case is that it is rolled around a solid crown. The body of a metal container has less rigidity in the radial direction, and as a result, under excess pressure in the can, the deformed ends bend the wall of the body, causing a change in geometric dimensions, and in critical cases - a loss of stability, which is expressed by the formation of wedge-shaped folds in the fold and ends that snap . This is also evidenced by the fact that in cans of small diameters, as noted by some authors |4, 6Y, flapping ends do not occur.

One of the reasons that eliminate this phenomenon is the increased rigidity of the body of such a container due to its small diameter.

Therefore, in addition to the already known recommendations of a number of authors on the development of the ends, it is worth increasing the rigidity of the can body, for example, by bending it |7| in places close to the place of rolling of the lid, as well as the use of such relief, which would form a stressed-deformed state along the perimeter of the lid, which excludes the possibility of irreversible deformation and depressurization of the container.

The end relief profiles recommended by various container developers do not fully take into account the features of packaging, subsequent sterilization techniques of packaged raw materials, excessive internal or reduced pressure in the container. When sterilizing a hermetically sealed container, the most dangerous, causing in some cases irreversible deformations of the ends and depressurization of the container, is the difference of internal pressure in the container over the external one. All relief profiles for canned metal containers have toroidal corrugations directed by their convexity to the outside of the can (Fig. 1, GOST 5981-88).

After deformation, the lid has a spherical surface with deformed corrugations, and the resulting expansion forces 52 (Fig. 2) in combination with compressive circumferential stresses сх (2) in some cases can cause irreversible deformations of the body and ends of the can.

During cooling, due to reduced pressure, the design of the lid should reduce the "vacuum" in the container. But the lid profiles discussed earlier have increased bending stiffness inside the can and do not reduce the load on the can body.

Another type of cans has ends with an initial deflection inside the can (according to the type of flapping membranes, with an initial collapse (21). When deformed due to excessive internal pressure, the lid deforms and straightens to a horizontal position (Fig. Za).

The resulting expansion forces 52 are directed to the outside of the ends of the can, thereby increasing the rigidity of the relief applied to the lid and unloading the body of the can in the place where the lid is rolled.

Using the properties of the concave membrane, French researchers (9, prototype) developed new designs of the relief profile.

The difference of this relief is that the bomb rings are made with a directed deflection inside the can. According to the authors, this makes it possible to reduce the increase in the volume of the vapor-air space under the cover when it is deformed under pressure. These reliefs have a number of advantages compared to reliefs and bomb rings with a convexity on the outside, because the execution of a bomb ring in the viewer with a convexity inside the can increases the stability of the relief and allows to reduce the pressure in the container during the sterilization process.

However, the specified relief profiles have (|9| some disadvantages. The height of the corrugations on the cover is equal to the height of the bomb rings, which increases the rigidity of the relief in the center. The elasticity of the relief is not adjustable in the radial direction, and in addition, this profile is not universal, that is, it is intended only for compensation of excessive internal pressure.

During pasteurization of canned goods by hot filling (up to 95 "C), the pressure during rolling is equal to atmospheric, and during cooling - the external pressure drop can reach 0.09 MPa, which causes vacuum deformation of the body of the can (especially for a large tin can). The indicated relief having a concavity inside cans and the increased rigidity of the ends in the specified direction increases the effect of the expansion forces 52. (Fig. 36). The angle of inclination of the side bombardment ring is equal to 30", which can cause jamming of the lid when it is deformed by its convexity to the outside of the can.

The useful model is based on the task of developing such a universal design of the lid (ends), the relief profile of which would satisfy the requirements of the manufacturer of the canned product in the case of excess internal pressure of reduced pressure or in the container during cooling and would exclude the possibility of irreversible deformations of the lid (ends), body and depressurization of containers.

The purpose of the useful model is to develop such a relief profile of the lid (ends) that would prevent the occurrence of residual deformations of the lid (ends) and the body of the can. The set goal of increasing the volume of the vapor-air space under the lid during the sterilization process and reducing it after cooling, increasing the rigidity of the edge support ring adjacent to the can body, is achieved due to the fact that the support and intermediate ring surfaces are located horizontally and stepped inside the can, and the place of attachment of each subsequent toroidal corrugation to the annular surfaces is located lower than the previous one by the amount of A; (Fig. 4).

Surrounding the toroidal corrugations located inside is a spherical surface, which is directed by the convexity inside the can. Displacement values A; depend on the thickness of the tin, the diameter of the can and the radius of the corrugation g. Under the action of excess internal pressure p, the lid straightens and the expansion forces 52 are directed outside the can, thereby strengthening the body of the can and preventing residual deformations of the lid. Toroidal corrugations, working as flat springs, return the lid to its original position when cooled.

In fig. 5 shows a section of the cover with two bomb rings. In fig. 6 shows a section of this cover on a larger scale.

In fig. 7 shows a section of the lid with two different versions of the bomb rings.

The lid (ends) is a corrugated membrane (Fig. 5), which has a support ring surface 1, one or more intermediate ring surfaces (3, 5), the number of which depends on the diameter of the can (the change in the diameter of the can can be from 1... 5), located parallel to the supporting annular surface 1 and bombardment rings of one 2 or several 2, 4...

Toroidal bomb rings (Fig. 5, 6) with a radius n-(10...20)6 (5 is the thickness of the tin), the center of which is located higher and at a distance of I-(0...15)6 from the previous ring, are attached to the rings in such a way that the inner part of the circle (item B, Fig. 6) is located lower than the point A of fixing the outer circle of the bomb ring by the amount

Ddi-(5...1535. If there are two or more bomb rings, the following intermediate ring surfaces (4...) are also staggered to the bomb rings (Fig. 5). The radii on which the bomb rings are located Vi, P» ... are chosen from the condition of sequence of elastic deformation of each section of the cover.

In the case of simultaneous deformation and the same stiffness of flat springs formed by toroidal corrugations, the radii Vi are determined by the equality of the areas of the supporting and intermediate ring surfaces (Fig. 5): - one bomb ring - 2

V. B. a. IN; Ve B (ba - two bomb rings - UZ Z, etc.

The cap (ends) works as follows (Fig. 5). When the sealed raw material is heated in the can, due to the internal pressure p, the lid begins to rise and elastically deform the toroidal corrugations (2, 4...) which act on the support ring A, strengthening the body of the can and preventing the appearance of circumferential compressive stresses.

When cooling, the bomb rings (2, 4 ...), working as flat springs, try to take their initial position and due to the eccentric fixing of points (A, B, C, 0 ...) the bending moment dependent on the force To (Fig. 6) restores the initial shape of the lid.

In order to reduce the negative impact of reduced pressure on the initial geometric shapes of the can, the first bombardment ring must have reduced rigidity and can be made in accordance with the recommendations given in the submitted application Me20031212408 dated 12.25.03 (fig. 7).

All the necessary parameters of the structural elements of the lid (Ni, r, Her, li) depend on the diameter of the can, the thickness of the tin, parameters of sterilization of raw materials and cooling of the product and are specified by calculation.

List of used sources: 1. Tymoshenko S.P., Voynovskiy-Kryger S. Plastin' i olapnyky. - M.: Fyzmatizdat, 1963. - 630 p. 2. Volmyr A.S. Flexible plates and shells. - M.; Gostekhizdat, 1956. -419 p. 3. Ponomarev S.D., Andreyeva L.E. Calculation of elastic elements of machines and devices. - M.: Mashinostroenie, 1980. - Z26 p. 4. Pavlov AN. Selection of the relief profile of the lids of preserved cans // Sat. tr. Valuable containers and packaging. -

Kaluga. - 1966, Vp. 3. - P. 352-366. 5. Kotelnikov A.F. etc. Tin can / A.s. Mo 1221069, 1985 b. Konopinsky N.A. Increasing the stability of metallic containers to internal pressure in the process of sterilization of canned food / A.r. thesis Ph.D. technical of science - Odessa, 1989. 7. Malameyen G.D. etc. Experimental study of the stiffness of cans of large sizes //

Refrigeration equipment and technology. - Odesa, 2003. - Mob. - Vol. 86. - pp. 73-76. 8. Malamien O.G., Tytova A.A., Malamien G.D. To the question of pressure calculation during sterilization of canned food //

Agrarian Bulletin of the Black Sea Coast. 36. Science. works / Tech. of Sciences Odesa State Technical University. - 2004. - 24. - Sat. 105-108. 9. Paradise. 2397333 Ngapse, Repesiyoppepepiv ah hopaz zotsyei5 poiattepi roshg roie5 a soivegmev. - 7 s.

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Claims (1)

A universal metal lid for cans, consisting of a curl, one or more toroidal bombs, rings, a support ring and intermediate ring surfaces, which is distinguished by the fact that the intermediate ring surfaces are staggered with respect to the support ring inside the can and are attached to the bomb rings in such a way, that the inner circle of the bombardment ring is located lower than the outer circle by a value equal to 5...15 thicknesses of the tin, and the centers of the circles that form the toroidal surface of the corrugations are located above the support ring or intermediate ring surfaces by a value equal to 0... 15 thicknesses of tin.