GB2060603A

GB2060603A - Cooling glassware-forming moulds

Info

Publication number: GB2060603A
Application number: GB8032866A
Authority: GB
Original assignee: Saint Gobain Emballage SA
Current assignee: Verallia France SA
Priority date: 1979-10-17
Filing date: 1980-10-10
Publication date: 1981-05-07
Also published as: FR2467825A1; PT71924A; FR2467825B1; ES8200851A1; PT71924B; IT1133932B; ES505890A0; BE885759A; ES8305664A1; GB2060603B; IT8025386A0; ES496026A0

Abstract

Cooling of moulds used for making glass articles, especially receptacles, is carried out by means of cooling members surrounding the mould cooled by a liquid such as water, the cooling members extracting heat by convection or indirect conduction. The rate of cooling is varied from one part of the mould to another to obtain a uniform temperature throughout the article during cooling. This variability is achieved, for example, by disposing between the mould and the cooling member either (1) free spaces of varying thicknesses, (2) spacer members of varying thicknesses, or (3) spacer members of varying thermal conductivities (e.g. Cu or Al). In Fig. 9, the mould exterior comprises two rings 40 which contact the surrounding cooler (not shown) and further rings 41-44 of varying lesser diameters. <IMAGE>

Description

SPECIFICATION Manufacture of glass articles The present invention relates to manufacture of glass articles such as bottles, flasks and pots. It relates more especially to a method and device for cooling moulds used in manufacture of these articles.

In the manufacture of glass articles by moulding from a parison, it is necessary to cool the moulds to obtain an article of good quality.

Generally cooling of the moulds is carried out by blowing of air onto their external wall, which has a number of advantages but also many difficulties.

Air is a cheap fluid. However to have an efficient cooling it is necessary that the blow air arrives in contact with the mould at high speed which on the one hand, requires a powerful impeller and thus a high consumption of energy and on the other hand, creates acoustic nuisance especially when to increase the efficiency of cooling there are used moulds provided with fins.

By way of illustration, on a Hartford IS8 machine, it is necessary to use a fan having a power of the order of 110 KW to obtain an air speed of the order of 40 to 65 m/s, which creates a noise having an intensity of about 90 to 1 10 decibels.

Further, in cooling by air the latter leaves the mould at a high temperature of the order of 60"C which renders the working conditions particularly troublesome.

To avoid these disadvantages, it has been suggested to cool moulds by internal circulation of heat-transfer liquids. This type of cooling has other disadvantages.

The heat transfer liquids used are organic liquids capable of working at high temperature, but are inflammable and therefore dangerous to use in the neighbourhood of incandescent articles such as parisons or bottles during their manufacture. Further they are liquids which on evaporation or thermal decomposition give toxic gases. Their use to cool moulds requires, therefore, tight inspection of the whole cooling circuit as the slightest loss of liquid can cause serious accidents.

There is also known indirect cooling of moulds by the cooling of external members of the moulds such as the mould carrier or hinge, especially by water. Such a cooling is described for example, in French Patent 2 260 076 and in French Patent 2 260 435. This type of cooling which is not very noisy, and is economic, is not however entirely satisfactory because it cools in a uniform manner the whole of the mould, whereas the quantity of heat to be dissipated is different according to the level of the mould forming the bottom, the body or the neck of the article.

The present invention obviates the disadvantages mentioned. It suggests a new type of cooling which is not very noisy, economic, not dangerous and very easy to control, capable of acting in a different manner at different points of the mould and which thus allows manufacture of articles having a very good surface state and an improved mechanical strength.

According to one aspect of the invention, the cooling of the moulds is indirect and is effected by means of external members surrounding the mould, cooled by liquid and themselves cooling the moulds by conduction or convection, and it is characterised in that the flux of heat exchanged between the mould and the cooling members at each location of the mould is adjusted, for example by creating free spaces having different thicknesses between the mould and these members, or placing between the mould and said members spacer members which are more or less thick or of a material having a greater or lesser conductivity for heat, for example copper or aluminium.Thus it is possible by interposing a lesser thickness of air or other material to cool more strongly the part of the mould forming the body of a receptacle in the mould than the part forming the neck, to obtain finally a temperature which is substantially homogeneous in all parts of the receptable during manufacture. It is possible to vary the cooling at different parts of the mould by varying only the thermal conductivity of the spacer materials. There are thus obtained receptacles of glass having a good surface state, generally better than that obtained with a cooling by air and free from scabbing, while increasing their rate of manufacture.

Preferably the cooling liquid is inorganic, most preferably water, optionally mixed with a small amount of glycerol. Its temperature is generally less than 1 000C and preferably less than 500 C.

When the liquid is water its temperature of use may fall to 400C or less. As a result the temperature of the hinge is low and it therefore may be made of a material which is lighter than cast iron, for example steel, without risk of deformation and further it may be touched without the risk of burns.

The external cooled members may be hinges having articulated jaws with which the machines for manufacture of receptacles are equipped, and which ensure opening and closing of the moulds.

They may carry out both cooling of moulds having a simple parison and cooling of moulds having double or triple parisons and also cooling of a mould for blanks as well as a finishing mould.

In one embodiment of the invention, each of the jaws of the hinge is formed of a single member carrying out a mechanical function and the cooling function.

In another embodiment of the invention, each of the articulated jaws of the hinge comprises two essential elements, an exterior element carrying out the mechanical function of the hinge and an interior cooling element surrounding the halfmould which comprises, incorporated in its body, a cooling circuit.

In another embodiment of the invention each jaw of a hinge may comprise two constituent members essentially separated by a space in which may circulate cooling liquid.

The intermediate spaces between the cooling members and the mould may vary from 0 to several millimetres, according to the size of the mould and their positions with respect to the mould. For example, the space between the cooling members and the mould may be of the order of about 1 mm at the level of the body of a bottle formed in the mould and of the order of about 2 mm at the level of the neck.

Devices according to the invention will be described by way of example with reference to the accompanying drawings in which: Figure 1 shows in schematic section an assembly of a hinge and a mould in a device in which each of the jaws of the hinge is formed of two elements.

Figure 2 shows the cooling elements of the hinge of Figure 1 in two half-views in section, one from above (A), the other from below (B).

Figure 3 shows in elevation a cooling element of the hinge of Figure 1 according to a view in partial section.

Figure 4 shows the element of Figure 3 in a developed peripheral section.

Figure 5 shows in plan, the exterior part of two jaws of a hinge.

Figure 6 shows in elevation, the exterior part of Figure 5.

Figure 7 shows in plan the cooling element of the hinge for a mould using a double parison, Figure 8 shows in elevation the cooling element of Figure 7.

Figure 9 shows in elevation an axial section of a finishing mould.

Figure 10 shows schematically a cooling circuit.

Figure 1 shows an assembly formed of a hinge provided with two jaws 1 and 2 surrounding two shells 3 and 4 forming a mould for manufacture of a glass bottle. Each jaw comprises an internal element respectively 5 and 6, surrounding a shell and provided with a cooling circuit 7 and 8, incorporated in its body. These two internal elements together form that which will be called the "cobler" of the jaw. The two internal elements forming the cooler are surrounded by two external parts or support arms 9 and 10 which may open to separate the two shells of the mould or close to bring them together as shown in Figure 1.

Between the internal surface 11 of the cooler and the external face 12 of the shells of the mould, there are provided free spaces 13.

Figures 2, 3 and 4 show the cooler of a hinge for a single mould in the manufacture of a simple parison. This cooler composed essentially of two half-cylindrical jackets of steel 5 and 6 of which the upper part 14 has a shoulder 1 5 for assembly with the exterior part 10 of the jaw on which- it is fixed by the screw 16, supports and surrounds the two shells forming the mould.

Each jacket comprises two parts: an upper body having side by side four vertical chambers 17 which extend over the major part of the height of the jacket and a bottom 1 8 closing the chambers and fixed to the body by screws 1 9. Each chamber communicates with the neighbouring one by the openings 20 placed alternately at each end so that the assembly forms a circuit of zigzag shape. The chambers each cover a length of arc of'about 45 mm and have a thickness of about 6 mm. The thickness of the wall separating the chambers from the interior surface of the two jackets is close to 6 mm.

Each jacket has two openings, placed one at the entry of the zigzag circuit and the other at the output of this circuit. These two openings are connected by ducts in a circuit for feed and evacuation of cooling fluid, not shown in these Figures.

Figures 5 and 6 show the exterior part of a hinge. This exterior part is formed essentially of two arms 9 and 10 articulated about the same fixed vertical axis 21. These two arms may be of cast iron, but preferably, for reasons of weight and ease of manufacture already mentioned, they are constructed of steel.

The arms have a shape adapted to that of the jackets, the latter being fixed by screws in threaded holes 22. Holes 23 are provided in the lugs 24 for connecting the arms to a member for controlling the opening and their closing.

A single hinge assembly may be used for cooling of several types-of mould and thus for manufacture of different articles.

Figures 7 and 8 show the cooler of a hinge for moulds for manufacture of blanks for bottles using a double parison. This cooler comprises two blocks 25 and 26, each provided with two halfcylindrical openings 27 and 28 for the mounting of mould shells. Only the block 25 is shown in Figure 8 which is a view along line VIll-VIll of Figure 7.

Each block is again formed of a.body 29 carrying chambers 30 and a bottom 31 fixed by screws 32 on the body and forming the lower limit of chambers 30.

In this embodiment each block has four chambers arranged two by two along two semicircles centred on the axes 33, 34 corresponding to the mounting of two moulds and communicating between themselves by openings 35 to form a zigzag circuit.

The chambers extend over the major part of the height of the blocks. Their length along an arc of a circle is about 45 mm whereas their thickness is about 8 mm. The thickness of the steel wall separating the chambers from the interior surface of the blocks is about 6 mm. Each block has two openings 36 and 37 in communication with the chambers for entry and output of the cooling fluid.

Figure 9 shows a shell 33 of a finishing mould adapted to different jaws and used for manufacture of a bottle of 1 litre capacity.

The shell of a mould has from the outside the shape of a half-cylinder having in its upper part a shoulder 38 serving for mounting on a hinge.

The exterior surface of the shell comprises a plurality of rings of greater or less height and different diameters.

With the exception of two or three rings 40 of the same diameter corresponding to the interior diameter of the cooler and serving as guides for positioning the shell in the cooler, all the other rings have smaller diameters which are all different, one from the others. The ring of smallest diameter 41 is situated in the upper part of the mould corresponding to the throat 42 of the article to be made. The diameters of the lower rings according to 42, 43 and 44 then increase in steps to reach a maximum diameter at the face of the mould. By way of example diameter dl, the smallest, may be 1 54 mm, the diameter d2 156.4 mm, the diameter d3 1 57.4 mm, the diameter d4 1 57.8 mm, the diameter do of the rings for positioning in the cooler selected may then be 158 mm.

This external structure of the mould using rings having different diameters creates variable spaces between the mould and the interior surface of constant diameter of the cooler. Because of this the cooling of the parts of the mould is differentiated according to their nature. Thus the upper part of the mould being spaced to a greater extent from the interior surface of the cooler than the lower part, is cooled less intensely. Given that the upper part of the mould corresponding to the throat 42 of the bottle is less heated by the hot glass than the part corresponding to the body 45 of the bottle, the differential cooling of the mould leads finally to a temperature which is more homogeneous in the mould and thus to a more homogeneous temperature of the article made and an improved surface state and increased mechanical strength.

Given a structure using rings of different diameter at the exterior surface of the shells of the mould rather than the interior surface of the cooler, there may be used a single cooler for different types of mould.

Figure 10 shows schematically a cooling circuit according to the invention using water as a refrigerating fluid.

A duct 46 feeds with water at about 1 60C a mixing regulator valve 47 controlled by a servomotor 48. There also arrives at the regulator valve by the duct 49 a part of the recycled water as described in the following, after cooling of the hinges. The mixed water leaves the regulator valve and passes by a duct 50 to which are connected a manometer 51 determining the pressure of liquid and also a feed meter 52 measuring its flow. The temperature of the water is measured by a thermocouple 53 functioning in relation with a regulator PID 54 (a regulator having an action proportional to the derived integral), acting on the servo-motor of the regulator valve to obtain a mixture of water at a temperature of about 200C.

On the principal feed duct 55 there are connected several branches each provided with a flow valve.

The principal duct may feed a plurality of hinges simultaneously to cool them, for each hinge the cooling circuit comprises two branches. Thus the two branches 56 and 57 each lead to one of the two parts 58 and 59 of the cooler surrounding the two shells 60 and 61 of the mould.

After having circulated in the zigzag circuits for cooling, the cooling liquid emerges at a temperature generally less then 400C and preferably from 26 to 300 C. These temperatures are measured by thermocouples. The two branches, equipped with flow valves 62 and 63 and flow meters rejoin as a principal duct 64 which is then divided into two, a first duct 65 ejecting from the cooling circuit a part of the lukewarm water which is possibly recovered for other uses, and a second duct 66 on which is mounted a pump 67 recycling the other part of the lukewarm water to the regulator valve 47.

The examples described with reference to the drawings are embodiments where each jaw of a hinge is formed of two essential elements, an interior element comprising the cooling circuit and an exterior element forming a support and controlling the closing of the mould.

In another advantageous embodiment of the invention, these two essential parts are formed of a single piece. There is thus eliminated play caused during assembly and thus improved control of the differential cooling.

Claims

1. A method of cooling a mould during manufacture of an article of glass, such as bottles, flasks and pots, in which external members surrounding the mould are cooled by means of a cooling liquid, said external members themselves cooling the mould by convection or indirect conduction and the flow of heat exchanged between the mould and the cooling members is varied between locations of the mould.

2. A method according to Claim 1, in which the flow of heat is adjusted by interposing between the cooling members and the mould spaces of different thicknesses, these thicknesses being greater at the level of the part of the mould forming the body of the article than those at the level of the part forming the neck.

3. A method according to Claim 2, in which the spaces are filled with air.

4. A method according to Claim 2, in which the spaces are filled with a solid material.

5. A method according to Claim 1, in which adjustment of the flow of heat is carried out by interposing between the cooling members and the mould, spaces filled with materials of different thermoconductivity at different locations of the mould.

6. A method according to any one of Claims 1 or 5, in which the cooling liquid is an inorganic liquid, preferably water.

7. A method according to any one of Claims 1 or 6, in which the temperature of the cooling liquid remains less than about 500 C.

8. A device for cooling a mould during manufacture of articles of glass, such as bottles, flasks and pots, comprising cooling means surrounding exteriorly shells forming the mould, the cooling means comprising a cooling circuit connected to an inlet and outlet for the cooling liquid allowing circulation of this cooling liquid, spaces being provided between the internal surface of the cooling means and the external surface of the shells of the mould and these spaces having different thicknesses, according to their positions relative to the other parts of the mould.

9. A device according to Claim 8, in which the cooling means surrounding the shells of the mould comprise hinges connected to articulated jaws for opening and closing the mould.

10. A device according to Claim 9, in which each articulated jaw of a hinge comprises about the mould an exterior element for mechanical function of the hinge and an interior element for cooling comprising the cooling circuit incorporated in the body of the interior element.

11. A device according to Claim 9, in which each jaw of the hinge is formed of a single member comprising the cooling circuit incorporated in its body.

12. A device according to any one of Claims 8 to 10, in which the cooling circuit is of zigzag shape in said cooling means.

13. A device according to any one of Claims 8 to 12, in which the cooling means are of steel.

14. A device according to any one of Claims 8 to 13, in which the spaces between the cooling means and the mould are filled with air and their thickness is a function of their location relative to the mould, this thickness increases from the location of the mould at which the base of a receptacle is formed to the location of the mould at which the neck and throat of said receptacle are formed.

1 5. A device for cooling moulds during manufacture of receptacles of glass, such as bottles, flasks and pots, comprising cooling means surrounding exteriorly shells of the moulds, said cooling means comprising a cooling circuit connected to an inlet and an outlet for cooling liquid allowing circulation of this cooling liquid and, there being provided spaces between the internal surface of the cooling means and the external surface of the shells of the moulds, these spaces being filled with materials of thermal conductivities which are different according to their location relative to the mould.

1 6. A method of cooling moulds, substantially as hereinbefore described with reference to the accompanying drawings.

1 7. A device for cooling moulds, substantially as hereinbefore described with reference to the accompanying drawings.