DE2902859A1 - LOCKING ARRANGEMENT FOR CONTAINERS, IN PARTICULAR FOR BOTTLES - Google Patents

Description

IMpL-Ing, Udo Skuhra

Patent attorney

.-j. Tel. Oi-9/4704170? 9 Q? fl 5 9

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POl98H

23 January 1979

Albert Obrist, Alte Therwilerstr. 12, 4153 Reinach, Germany

Closure arrangement for containers, in particular for bottles

Closure cap made of flexible plastic for a container, which is used to hold a liquid which causes an internal pressure in the container is determined and has a container neck on which the closure cap for closing the container mouth with an outer approximately cylindrical union part in the axial direction positively can be applied, with a sealing part which can be placed against the container neck with sealing engagement in the region of the mouth of the container neck, that with one of the cap closure, the internal pressure of the container exposed base plate is connected, the base plate when an excessive internal pressure of the container by a Bulge distance is moved away from the container mouth.

909833/0897

Such closure arrangements are known and used in large numbers and e.g. in the following German patent applications by the applicant: P 23 11 838.9, P 26 44 845.3, P 25 29 340.7, P 25 29 289.1 and P 25 30 650.7. Such closure arrangements have proven themselves extraordinarily well in practice and in particular ensure reliable sealing the standardized glass bottles. (E.g. MCA or MC standard).

There are also a variety of other similar locking arrangements has become known, which by a plurality of seals, if necessary Try to compensate for the inadequate sealing effect of individual sealing parts. Such a cap is e.g. of the German Offenlegungsschrift 27 03 404.4 (Grussen) In addition to a relatively deep inner seal, an additional upper sealing section and one on the outside proposed the sealing section attacking the bottle mouth. This Closure has a number of disadvantages and is particularly useful for filling carbonated beverages with high internal pressure poorly suited. It has been shown that the internal pressure in such bottles when stored under high Temperatures can rise to such an extent that either the bottle itself is destroyed, or that at high temperatures as well elastic or softening plastic fastener in the area of the thread is widened in such a way that the closure is bullet-like is blasted off the bottle. Even if the inner seal, for example, leaks due to the excessively increasing pressure and would allow a pressure reduction, the bottle would still be kept closed, in particular by the outer seal, which means an explosion of the bottle or forcible destruction of the closure is practically inevitable.

Requirements of the beverage industry with regard to consumer safety, such closure arrangements even at temperatures of 600 c can be safely maintained because of the fluctuating Carbon dioxide proportions of various drinks and the possible Strength fluctuations in glass bottles or, in particular, plastic bottles with most known plastic closures not be met.

909833/0597

In German it became the apparent solution to blow-off problems Utility model 18 87 597 (Middleton Plastics Ltd.) already proposed, the bottom plate of a screw cap in the middle part to be provided with an elastic membrane which is pretensioned against the edge of a bottle mouth and which when the Internal pressure in the bottle is increased to allow the pressure to be released. In practice, this solution was therefore particularly successful not enforce, because the sealing effect of the membrane on the inner edge of the container is in many cases insufficient. So already leads every smaller pressure increase in the container leads to a partial relief of the diaphragm pre-tension, which leads to a premature pressure reduction can lead. Changed in the event of fluctuations in the diameter of the container mouth In addition, the depth of engagement of the membrane, which leads to additional Sealing problems leads.

Because the seal of the membrane is approximately circular on the sharp inner edge of the container mouth takes place, each lifting of the membrane leads to an opening of the container. The membrane works accordingly as a valve with the sealing pressure decreasing towards the open position. Obviously, this arrangement is extremely critical with regard to tolerance fluctuations, e.g. with regard to the membrane wall thickness, the mouth diameter, the membrane material or the screwing torque. Membrane closures of this type are therefore particularly useful for closing standard beverage bottles absolutely unsuitable.

The object of the invention is to avoid the disadvantages of the known, in particular to create a locking arrangement, what consumer safety for carbonated beverages too guaranteed at high temperatures and high internal pressures.

According to the invention, this object is primarily achieved by that the sealing part consists of a sealing cylinder that extends away from the base plate and can be pushed into the container neck, which has an outer sealing section which, for sealing contact with the inner wall of the mouth, is perpendicular to this acting sealing bias is determined in an operating sealing distance from the upper boundary surface of the container mouth

9833/0597

ORIGINAL INSPECTED

is and which sealing cylinder along an approximately annular Connection point, the outside diameter of which is the same or smaller, than the outer diameter of the sealing section is connected to the cap base, and that the closure cap is made of a plastic exists, the flexural rigidity of which increases above room temperature Temperature decreases in such a way that the base plate at least in the annular area between the cover part and the annular area Connection point forming a circular ring-shaped Bending zone around the bulging distance (h) due to the excessive internal pressure of the container Can be arched out, which arching width is equal to or greater than the minimum sealing distance of the sealing section from the upper one Boundary surface of the container mouth, in which the outer Sealing section like a piston from sealing engagement with the inner wall of the mouth is lifted.

The invention thus creates in the simplest possible way and without additional technical or material expenditure a closure arrangement which permits the automatic pressure reduction and which is suitable for a wide variety of Beverage bottles or containers and also plastics and cap configurations are customizable and applicable.

In particular due to the sealing part, which can be displaced cylindrically in the container neck and which is continuous and piston-like when the pressure rises is shifted from the operating sealing distance to the minimum sealing distance, the invention ensures an opening process that takes place slowly and only after displacement of the sealing part over a distance that can be adapted to the application. This means that at Pressure increase in the container, although the seal from the operating position in Is shifted in the direction of the minimum sealing distance, but there is still no relief of the contact pressure of the sealing section and thus there is no impairment of the sealing effect. Rather, the one remains perpendicular to the inner wall of the mouth, i.e. the one after outwardly directed seal pretensioning force remains unchanged until the minimum sealing distance is reached.

The invention also makes use of the consideration that the pressure rise in a carbonated liquid containing it Containers dangerous values only at higher temperatures.

909833/0697

... inspected

enough. At the same time plastics are known, which with increasing Temperature become more elastic and the one cap dimensioning allow which at normal temperatures - and "harmless" Pressure values - seal the bottle reliably and only from a predetermined temperature - and thus a predeterminable one Value of the internal pressure - are elastically deformable in such a way that the sealing section is controlled in the direction of the minimum sealing distance is raised. The fact that, when the temperature drops, the The elasticity of the plastic decreases again and, accordingly, the sealing section is returned to the operating sealing distance.

The minimum sealing distance does not necessarily have to be with the upper edge cursing the bottleneck «In fact, it has been shown that especially for bottles with a rounded inner mouth edge when the sealing section is partially raised, the lateral contact pressure on the sealing section decreases in such a way that gas can escape can.

The invention is also particularly advantageous for closing Plastic bottles can be used. In such bottles it has been shown that with increasing temperature due to the expansion of the Plastic material, an increase in the volume of the bottle occurs, which leads to an increase in the "head space" above the liquid leads. This increases the risk of blow-off.

The closure arrangement according to the invention can be particularly advantageous for closing MCA mouths or similar Use muzzle configurations when the cap is off Polypropylene exists when the operational sealing distance is about 1.0 to 2.2 mm and when the bottom plate is about 1.3 to 0.7 mm is thick. Depending on the design of the inner edge of the bottle mouth and the dimensions of the closure cap, excellent Values and precisely controllable pressure reduction points as a function set by the temperature. Particularly advantageous results were obtained with a wall thickness of the "base plate (without reinforcement ribs) of 0.8 to 1.0 mm and a minimum sealing distance of about 1.6 to 1.4 mm.

909833/0597

Obviously, the invention can be carried out by simple temperature experiments can be adapted by the person skilled in the art to the most varied of configurations and plastic materials, without the Thought of invention would leave.

If, for example, in individual cases polypropylene is to be used instead of polyethylene, which is known to be more elastic, then the wall thicknesses are Either to increase in the area of the cap base or, for example, by means of reinforcing ribs or lateral reinforcement To create stabilization arrangements in order to avoid sagging at low temperatures. In addition to the inner seal, you can In the individual case, sealing sections are also provided which rest against the upper edge of the bottle mouth, insofar as this can also be disengaged from the bottle due to the elastic deformation of the cap base at higher temperatures.

However, the arrangement of an inner seal as the "main seal" is indispensable to the unavoidable that occur with standard bottles Bridging tolerances and preventing the bottles from leaking at lower temperatures.

As can be seen, the technical progress and the inventive Content of the subject of the application not only through the new individual features but also in particular through the combination and Subcombination of all used features guaranteed.

The invention is illustrated below in exemplary embodiments using Drawings explained in more detail. Show it:

Fig. 1 The schematic representation of a closure arrangement with the features of the invention at room temperature on average,

FIG. 2 shows the closure arrangement according to FIG. 1 at 600 q and at the moment of the pressure reduction,

909833/0597

3 shows a modified embodiment of the invention with modified inner gasket and additional head gasket, and

FIG. 4 shows the closure arrangement according to FIG. 3 at 60o c.

The closure arrangement according to FIG. 1 and FIG. 2 has an im Part cut open bottle neck 1 with external thread 2, which is connected by a cylindrical screw cap 3 with internal thread 4 is lockable. On the cap bottom 5, which forms the top, an inner seal 6 is provided, which is known in Way, the bottle neck 1 seals the inside along a circular line or area. The drawings are not to scale.

The operating sealing distance a of the sealing section 7 in engagement with the bottle neck from the upper edge 8 of the bottle neck 1 is approx. 1.5 mm. The thickness d of the cap base 5 is 0.9 mm. The screw cap 3 is made of polypropylene and is in known way produced by injection molding.

FIG. 2 shows the screw cap according to FIG. 1 after prolonged heating of the filled bottle above a previously known critical temperature. It can be seen that this is the material of the cap base 5 heated in such a way that its elasticity increases. The internal pressure that increases with increasing temperature in the bottle, the is indicated schematically by an arrow in Fig. 1 and Fig. 2, causes a curvature of the cap base 5 over the minimum sealing distance in addition by an amount which corresponds to the amount h. As a result, carbon dioxide flows between the upper edge 8 and the sealing section 7, with sufficient leeway and tolerances exist between the internal thread 4 and the external thread 2 to allow the escape and to allow the complete pressure relief ... as soon as the internal pressure is dismantled, the cap base 5 returns to its original position to such an extent that between the sealing section 7 and the bottle neck 1 there is renewed sealing engagement. This process can of course repeat as often as by increasing further or sustained warming of the bottle, the internal pressure, the critical

909833/0597

" ¹⁰ " 29Q2859

table value again exceeds.

Fig. 3 and Fig. 4 show a somewhat modified embodiment of the invention with an additional end seal 9, which consists of two concentric, approximately wedge-shaped tapering sealing sections on the cap base, and which engages the upper boundary surface of the bottle neck 1. There is also the inner seal 6 embodied approximately trumpet-shaped in a manner known per se and lies with the outer edge on the bottle neck 1 in a sealing manner. The inner seal 6 is so elastic that a pressure reduction can only take place when it is raised above the upper edge of the mouth edge. The bulging width (h) must therefore correspond to the operating sealing distance (a) in order to ensure the function according to the invention.

Analogously to FIG. 2, FIG. 4 shows the closure arrangement in a heated state State, it can be seen that both the end seal 9 as the inner seal 6 also disengage from the bottle neck 1 when the critical internal pressure is reached, and the outflow of carbonic acid.

The mode of operation of the invention is explained in more detail using an example explained.

Example 1:

40 conventional beverage bottles with a volume of one liter are filled with a carbonated drink leaving a small head space. The carbon dioxide content in the drink is 8 grams per liter. The bottles are 20 standard glass bottles with MCA neck and 20 plastic bottles, also with MCA neck. The bottles come with a Screw cap made of polypropylene closed. The internal thread of this screw cap is adapted to the configuration of the external thread of the bottles and takes into account the tolerance field of the Bottle thread. The cap base has a thickness of 0.9 mm over the entire surface. There is an inner seal on the bottom of the cap a configuration analogous to FIGS. 1 and 2 is provided. The distance h of the sealing section from the upper edge of the mouth is 1.5 mm.

90983370597

ORIGINAL INSPECTED

The closure is manufactured and made using the injection molding process made of polypropylene. {Mixture of copolymer and homopolymer polypropylene in a weight ratio of 50:50 and with a resulting Ε module of 1050 N / mm2; Manufacturer of the raw material Fa. Hoechst).

The screw caps are screwed or tightened onto the bottles with a torque of 8 to 12 cmkp. The thus capped bottles are placed in a water _s which the bottles beyond the closure cover. The water bath is at room temperature of 20o c and is slowly heated to approx. 550 c over a period of one hour. At this temperature, carbonic acid bubbles gradually begin to emerge from all closures between the lower edge of the closure and the bottle. The bubbles mostly occur at an interval during which the pressure reduction obviously takes place. The release of the bubbles then ceases for a certain period of time, only to start again after a period of renewed pressure increase in the bottle.

Calculation and comparison tables can be used to determine, that with a carbonic acid content of 8 grams per liter at 550 c There is a pressure of about 10 bar in the bottle. This pressure was for the given bottle material, as well as the dimensions of The thread and outer wall of the screw cap are still uncritical. A higher pressure of over 12 bar, on the other hand, is considered critical Limit considered.

All screw caps are at the top, i.e. at the bottom of the cap before and during the pressure reduction or the release of carbonic acid bubbles clearly bent. One done by hand mechanical load of the screw cap in the opening direction results However, that the screw caps sit firmly on the bottle and do not move even if there is additional tensile stress Pull the screw cap over the thread or let it snap off.

Subsequently, all the bottles are heated evenly during a short c further period of about 15 minutes to 600 and held at this temperature for about three hours.

909833/0 59?

During the entire further heating process, gas bubbles continue to emerge from all closures. The locks are in place but firmly on the bottles. All cap bottoms are bent.

After four hours, the water bath is cooled back to room temperature. The bulge of the cap base goes back on all closures. There are no more gas bubbles. After When the bottles are removed from the water bath, it is found that all the cap bottoms are back in their original position. All bottles can be opened by hand. It can be clearly seen both during this and during resealing attempts determine the engagement or disengagement of the inner seal with the bottle neck by changing the torque. A measurement of the carbon dioxide content of the drinks shows a decrease of $ 20 to approx. 6.4 grams. The maximum values are 7 grams and 5 grams per liter.

By calculation or from comparison tables it can be determined that 'the maximum internal pressure at 60oC and 6.4 grams of carbonic acid per liter is approx. 8.5 bar. It follows that in the bottles initially had a pressure increase to approx. 10 bar up to around 550. With this increase in pressure, the elastic cap base is bent, the seal disengages and a pressure reduction takes place, which continues during the entire further heating and which is down to about 8.5 bar (corresponding to 6.4 gr. carbon dioxide per liter). Due to the elasticity of the bottom of the cap, at this pressure of 8.5 bar, the bottle is at a Temperature of 60o c kept closed.

The originally achieved pressure of 10 bar up to the first pressure reduction at 550 c is due to the fact that the inner seal with a certain preload and correspondingly acting frictional forces sits in the bottle neck, which is in addition to the counter pressure of the cap base must be overcome. After the initial dismantling, the pressure is then apparently equalized at around 8.5 bar, which corresponds to the counter pressure of the cap base.

9098 3 3 / OB 97

Overcoming the frictional forces between the inner seal and the bottle neck obviously causes a certain reversal error, which, however, only has a minor influence on the effect achieved and obviously through appropriate tolerance measurement and Shaping can be controlled. Arises! I also will already at a value which is clearly below what is still permissible considered value of 12 bar, the pressure reduction is even The remaining 6.4 grams of carbonic acid per liter also means no noticeable loss of taste in the Soft drink.

Example 2:

Of the bottles used in the first example, two, which lie approximately in the center of the port tolerance range are taken aer amount of the bottles used in the first attempt. The bottles are filled with clear water up to Mormalhöhe and then closed in the same way as in the first attempt with a plastic closure of the type described :.

In the middle of the bottom of the two screw caps was a commercially available one Valve inserted and fastened in a small hole, which makes it possible to connect the closed bottles to a compressed air network to be connected and the interior of the bottle tinter pressure set.

The bottles prepared in this way are put back in the water tank at a temperature of 20oC. The valves in the center of the bottle caps are one with the outlet tap Compressed air network connected. The supply line is with a compressed air measuring device connected, which allows the created or the Measure the pressure in the bottle. Now the air valve becomes light opened and a continuous pressure increase begins, which initially at 10 bar by closing. the cock interrupted will. The two bottles are during the entire pressure rise completely tight, no air bubbles emerge. After a period of 15 minutes the pressure is increased further up to one Final value of 13 bar. There is also nothing on the closures Air bubbles out.

The bottles are then placed in a water bath for four hours, with the caps as in the first attempt only a few centimeters of water to avoid back pressure.

After the dwell time, the bottles are taken out of the water bath and the pressure in the bottles is measured again with a manometer, whereby the value of approx. 13 bar is confirmed. the Compared to the first attempt, closure caps are only slightly bent in the area of the cap base. The sealing caps are still stuck, although the "critical" value of 12 bar, set for safety reasons, has already been exceeded.

The experiment clearly shows that the closures with lower Temperatures can be exposed to significantly higher pressure loads without a pressure reduction taking place. In practice This means that, for example, short-term pressure drops caused by strong shaking during transport or in some other way do not lead to a loss of pressure.

The desired pressure reduction only occurs if the bottle and cap are over in an actually critical situation a predetermined point can be heated, it can be assumed that critical pressures in the bottle as well can only be achieved at high temperatures.

As can be seen from the exemplary embodiments and the experiments, the invention makes use of the material properties of plastic and a certain dimensioning capability in an optimally simple manner in order to solve a long-standing security problem. This is done in the simplest possible way, surprisingly even extraordinary economic savings can be achieved, since the described Kurrststoffverschltfss, for example in comparison to aluminum closures, guarantees at least 40% cost savings with drastically increased security. This applies erschlössen aiuch compared to other plastics that have been trained in the rule just to ensure greater stability bucket with much thicker walls.

$ 098 33/059?

Obviously, the basic idea of the invention can be understood here largely adapt to specific arrangements and dimensions, as well as materials, without departing from the basic idea of the invention. It is easily possible for a person skilled in the art to carry out simple test series, e.g. according to case example 1, the Correct dimensioning for wall thicknesses for a given material or the correct material selection for given wall thicknesses depending on the penetration depth of the seal and the diameter of the cap base. Also taking into account the friction between the inner seal and the bottle neck does not mean anything special Problems, as can be seen in the first case example.

Since the pressure increase in beverage bottles is only relative in practice happens slowly and increases according to the bottle warming e.g. in sunlight, a weakening is often enough the sealing section, in order to enable a comparably slow pressure reduction.

The invention s diafft a closure arrangement for bottles for receiving carbonated beverages with a plastic cap, in particular a plastic screw cap with an inner seal protruding into the bottle neck. The screw cap is made of such elastic Material made and has such a configuration that at rising temperature and rising internal pressure carbonic acid and / or fluid is drained.

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Claims (5)

Diploma in Ing. Udo Skuhra PatfintsnwrJt 2 9 Ω 9 ft ^ " ^ ft W U Z Q ν) RimaTd-Slrai! Ü-jtr.9.T «1.0H9 4/0 4i7C
D-80U0 Munich SO ΡΟΊ98Η January 23, 1979 Albert Obrist, Reinach / Switzerland Claims i1 / cap made of flexible plastic for a container, the effect of absorbing an internal pressure in the container Liquid is determined and has a container neck on which the closure cap for closing the container mouth with an outer approximately cylindrical coupling part in the axial direction Can be applied in a form-fitting manner, with a sealing engagement that can be applied to the container neck in the region of the mouth of the container neck Sealing part, which forms the cap end with a, connected to the bottom plate exposed to the internal pressure of the container is, the base plate when an excessive internal pressure of the container occurs is moved away from the container mouth by a bulging distance, thereby marked t, d a s s the sealing part (6) from one which extends away from the base plate (5) and can be pushed into the container neck Sealing cylinder consists, which has an outer sealing section (7), which for sealing contact with the mouth inner wall with a sealing bias acting perpendicular to this is determined in an operating sealing distance (a) from the upper boundary surface of the container mouth and which sealing cylinder along an approximately circular connection point, whose outside diameter is equal to or smaller 909833/0597 ORiQfMAL than the outer diameter of the sealing section with the cap base is connected, and that the cap consists of a Plastic is made whose flexural rigidity is above room temperature increasing temperature decreases in such a way that the base plate at least in the annular area between the cover part and the annular connecting point with the formation of an annular bending zone around the bulging distance (h) can be buckled due to the excessive internal pressure of the container, which bulge is the same or greater than the minimum sealing distance of the sealing section from the upper boundary surface the container mouth, in which the outer sealing section is lifted like a piston from the sealing engagement with the mouth inner wall. 2. Closure cap for producing a closure arrangement according to Claim 1, in particular on bottles with a bottle mouth approximately corresponding to the 28 mm or 38 mm standard mouth, characterized in that the operating sealing distance (a) about 1.0 mm to 2.2 mm. 3. Closure cap according to claim 2, characterized in that the base plate (5) is 1.3 mm to 0.7 mm thick and that the base plate is made of polypropylene. 4. Closure cap according to claim 3, characterized in that the wall thickness of the base plate (5) is 0.8 mm to 1.0 mm and that the operating sealing distance (a) is 1.7 mm to 1.3 mm. 5. Closure cap according to claim 4, characterized in that the operating sealing distance (a) is 1.6 mm to 1.4 mm. 909833 / 0S97