MXPA98007014A - Mol cooling system - Google Patents

Abstract

The present invention relates to a system for cooling molds for forming machines for glass articles, of the type comprising a mold cooling system using a fluid as a cooling medium, the invention being characterized by a plurality of the present invention. of blind holes connected to a multiple head formed in the upper part of the same body of each mold half by means of a circular groove and a flange of the same shape placed on the same groove as a hermetic cover, which in turn is connected to a capacitor placed vertically on the mold, inside said holes of each half of the mold is located as a cooling fluid, a liquid with phase change that by gravity returns the fluid from the condenser to the molds, means to maintain a circulation of a second cooling fluid through the condenser and means for venting said condenser to the ambient

Description

SYSTEM FOR COOLING MOLDS BACKGROUND OF THE INVENTION In the glass molding industry, particularly in the operation of multi-cavity machines for the molding of glass containers or the like, the cooling of the molds is a critical factor, in terms of the life of the mold, the quality of the mold. molded article and operating speed of the molding machine. The higher the speed of operation of the machine, the greater the number of products produced per unit of time and the greater the amount of heat absorbed by the mold per unit of time. Therefore, it is noteworthy that, when increasing the speed of operation of the machine, of this type, the amount of heat transferred from the glass to the mold per unit of time, is greater, in turn, in greater quantity per unit of time must be extracted and uniformly, the heat of the mold. In the past, it was common practice to use air-cooled molds, but these were inefficient and required fans driven by electric motors with requirements of around 300 horsepower.

In order to carry out a more efficient cooling process, the use of ld instead of air was proposed. However, this method was not only difficult to control but, in most cases, resulted in a very rapid cooling of the mold with the consequent reduction in the quality of the molded product.

Previously, by studies and practices, I have been able to develop a method where each mold is formed by a plurality of blind holes that extend axially in the body of the mold between the molding surface and the outer surface of the mold, and, where drill holes are at least partially filled with a ld that changes state, such as distilled water. The holes are connected to a common multiple head located at a higher level than the mold, and this in turn, connected to a condenser located vertically on the multiple head by a conduit. In this way, it is formed between all these elements, a hermetic chamber. Subsequently by tests performed I realized that it is possible to increase the cooling efficiency of the mold by transferring heat from the mold itself to a ld that changes phase and vaporizes, rises up through the common manifold until it reaches the condenser where it is cooled and returned to its ld state and falls by gravity towards the individual blind holes where it was originally located. I found that the most efficient and controllable cooling occurs when the heat of the mold is transferred not to a ld, but to a vapor which is in contact with the walls of said blind holes.

Particularly in the case of multiple cavity molds, it was good practice to use a single common manifold head in each mold half. This arrangement made it possible to provide and control the heat extraction per unit time selectively for each mold means, and consequently, to ensure a uniform quality of glass articles formed in multi-cavity molds.

However, although technologically efficient, it requires a head that surrounds the outer surface of the mold half and communicates through a plurality of connections with an equal number of mold cooling holes. In practice, this operation has required intensive labor consumption to maintain a horizontal level with acceptable precision that guarantees a uniform feedback of fluid to all the holes. Additionally, the connection of the head with each of the holes of the mold hinders the required airtightness to avoid the leakage of the cooling fluid of phase change. Another important limitation when it comes to molds with very irregular article design, is the lack of control of the amount of feedback fluid that is individually fed to each hole in the mold.

With the apparatus of my invention, it is possible to achieve a multiple head that provides a precise, uniform level and immune to the stresses caused by the handling during assembly, ensures the tightness towards the outside of the connections of each hole, significantly reduces the assembly time of each mold and is capable of selectively controlling the flow of feedback fluid in each of the holes of the mold according to the thermodynamic profile required by the glass article.

BRIEF DESCRIPTION OF THE INVENTION According to the present invention, the use of a multiple head integrated into the body of the mold means, not connected to it, makes it possible to feed back fluid uniformly in all holes drilled therein.

Additionally, it makes it possible to control the heat extraction per unit time selectively not only for each particular mold medium, but also in specific areas of each mold means. This consequently ensures a uniform quality of glass articles formed in molds especially in those of multiple cavities. Said common head is formed in the body of the mold by machining a groove in a semicircular shape, which is then covered by a sealed flange. The seal between the flange and the body of the half mold, is achieved by arc welding with alloy contribution of the type that forms an alloy with the base material of the same mold, and with the material of the cover and that also, the coefficient of expansion The thermal value of the weld filler is located at an intermediate point between the value of the coefficient of the material of the mold and the material of the flange. For most of the cases, where the material used is cast iron, commercially, there are welds that fulfill this requirement, generally those made of nickel to be applied through the process of arc welding, or, the welds based on copper and Silver when the autogenous welding process is used. In this way, an airtight cavity is formed that communicates precisely with all the half mold holes. The bushing is placed at the entrance of each of the holes and contains a capillary slot with variable trajectories and geometries. This capillary slot allows the control of the amount of cooling fluid that enters each hole selectively in accordance with the thermodynamic requirements of the heat transfer profile demanded by the glass article. The materials used to manufacture the bushing are copper alloys, or those that have a greater thermal expansion than the material of the mold, in this way, it is possible to create a seal between the outer surface of the bushing and the material of the mold where When the mold is heated to the operating temperature, when it is cooled, there is a play due to the greater shrinkage of the material of the bushing sufficient to remove it or to change the orientation of the capillary slot easily, when an adjustment of the thermodynamic profile. If necessary, it can be manufactured with a plurality of capillary grooves in each bushing placed in a variable orientation in all 360 degrees of circumference in order to obtain greater precision with the thermodynamic profile of the glass article. The distribution of the capillary grooves is based on studies of finite elements that determine the isothermal maps of the mold.

DESCRIPTION OF THE INVENTION The characteristic details of the present invention are clearly shown in the following description and the accompanying figures as an illustration of that and serving the same reference signs to indicate the same parts in the figures shown.

Figure 1. Shows a diagrammatic view of the mold, the integral multiple head, the condenser and the atmospheric vent valve.

Figure 2. Shows a more structured sectional partial view of a mold medium and the sectional view of the multiple head and the connection line to the condenser.Figure 3. Shows a partial elevation of a mold means showing a glass article and two blind holes shown with interrupted line.

Figure 4. Shows a top view of the mold means in figure 3.

Figure 5. Shows a diagrammatic view of the different forms of blind holes that can be practiced in the mold.

Figure 6 shows an elevation of a control bushing showing a phase change cooling fluid flow control slot, as well as a threaded center hole for the steam outlet.

Figure 7 shows a top view of the control bushing shown in Figure 6.

With reference to said figures, in figure 1, which illustrates the heat transfer principles involved. The mold is indicated with the number 1, and a portion of the mold surface 2,. The blind holes 3, which are located in Figure 2, are formed vertically in the wall of the mold and placed approximately half the thickness between the surface of the mold and the outer surface of the mold itself. . It is to be understood that each mold half includes plurality of such holes 3. Each hole 3 is connected to a common multiple chamber formed by a slot 4, made in the upper face of the mold 2 and in a semicircular shape which is then covered and sealed by a flange 5, placed in the slot 4, in such a way that the upper surface of the mold 2, and the upper surface of the flange 5, remain at the same height. Threaded holes 6, shown plugged with plug 7, are made in the flange, in number and placement equal to holes 3, so that the holes are located just above each of them. The threaded holes 6 allow access to the flow control bushings 8. Line 9 communicates to slot 4, and capacitor 10, which is positioned vertically above the mold level. The connections 11 and 12 allow the circulation of a cooling fluid through the condenser 10, but without allowing contact with the fluid contained in the cooling system of the mold. The upper end of the condenser 10 is vented to the atmosphere through a valve 13. An adjustable flow restriction 14 can be placed on the line 12 to control the amount of cooling fluid entering the condenser 10.

In operation, the heat transfer from the molten glass 15, towards the mold, shown in Figure 3, and Figure 4, is capable of at least partially evaporating some of the liquid that is located in the holes 3. The vapors rise by density change towards the condenser 10, where it is at least partially condensed and the drops thus formed, return by gravity to the multiple head formed by the slot 4 and the flange 5 and consequently, to the holes 3. Therefore, there is a closed system that does not require a replacement of cooling fluid since the same fluid is being recycled through the formation of phase changes, from liquid to vapor in the hot zone of the mold medium and from vapor to liquid in the area cold condenser. The condensing capacity per unit time is thus adjustable by means of the flow variation device 14 and by controlling the temperature of the cooling fluid circulating through the condenser 10, through the connections 11 and 12. We have mentioned the operation of the system in general. Now, seeing in detail what happens specifically in the mold with respect to heat transfer, we observe that the geometry of the article (15), and the thickness of the wall of the article (15), dictate a variable thermodynamic profile along and mold width. These parameters were not satisfied by conventional methods. However, at present, that higher speeds of operation of the glassware forming machines of the type we are referring to are demanded, the ability to extract heat from the mold faithfully following the thermodynamic profile, it is of an important benefit to satisfy the high speeds of operation as well as the higher levels of quality that are required. To achieve this detailed control of heat transfer, the bushings 8 are placed at the entrance of the holes 3, with a sector projected on the level of the slot 4, in such a way that the level of the feedback liquid is partially raised and it is forced to pass through a capillary control groove 16, A threaded hole 17, made in the center of the hub 8, allows the exit of the vapors resulting from the evaporation of the cooling fluid on its way to the condenser. Additionally, the thread made in the hole (17) of the bushing (8), allows the handling thereof through the access opening 6, formed on the outer surface of the flange 5. Additionally, in figure 7, it is shown a mark (18), made on both sides of the flow control bushing (8) and related to the slot position. This mark facilitates accurate verification of the exact orientation of the bushing (8). In this way, it is possible to orient the hub in multiple positions in all the 360 degrees of the circumference of the bushing (8) to follow the thermodynamic profiles that the article (15) requires. Figure 3 shows a glass article in section positioned in the mold 1, as well as two of the blind holes 3 shown with interrupted line. Figure 4 is a top view of the half of the mold of Figure 3, showing the arrangement of the flange 5, and the connection of the flexible line 9. Figure 5 is a diagram illustrating various configurations of the holes blind 3, holes 3 A and B, differ only in diameter while 3C is formed by a slot in "V" screwed in order to increase the area and therefore the heat transfer capacity. The 3F 3D holes included illustrate different configurations that affect the transfer of heat to different locations of the molded product. 3Y and 3J, illustrate removable plugs that, like the previous ones, can be adjusted to control the heat transfer rate in selective areas of the mold.

Figure 6 is the elevation of the hub that controls and directs the flow of coolant fluid. Illustrated in these figures, for clarity, a single capillary slot, as well as the hole screwed to the center, which allows the manipulation of the hub. Figure 7 is a top view of the cooling fluid flow control and direction bushing shown in Figure 6.

When referring to the glass machine we refer to large multi-cavity machines for the simultaneous formation of plurality of molded articles (15) such as glass bottles. When a machine of this type starts the process, the vertical holes are at least partially filled with cooling fluid such as distilled water. The molding process is thus initiated, the speed of production is increased according to a quantity of cooling fluid adjusted by the device (14), until a stability of the quality of the glass articles (15) is achieved. Any problem caused by an overfill of the holes (3), is automatically resolved by the operation of the vent valve (13). It is easy to understand by connoisseurs of this art that a common multiple head formed in the body of the mold can be practiced by any process of removal of the mold material, such as machining with a cutting tool. That in this way it is possible to maintain a precise level and communicate to all holes (3) located in the same mold, ensuring that its level is protected against blows caused by handling during installation since the entire manifold is located integrated into the body of the mold, and therefore does not require additional space to the mold that is very scarce in the vicinity of the mold (1). That the extraction of heat selectively three-dimensionally in the body of the mold (1), and in specific areas, according to the profiles of the isotherms of the mold (1), it is possible to achieve this by using a bushing (8) with capillary groove with variable geometries and trajectory, oriented in a specific direction to satisfy with greater precision the thermodynamic profiles required by the article (15) of glass. Which tapped threaded holes in the flange (5) and placed exactly on each hole (3), eventually allow access to the bushings (8) to remove or change orientation.

Claims (1)

1. CLAIMS Having described the invention, I consider it a novelty and therefore I claim as property of my client what is contained in the following clauses: The system for cooling molds for forming machines of glass articles, of the type comprising a cooling system of molds using a fluid as a cooling medium; in the present case being the invention characterized by a plurality of blind holes connected to an integrated multiple head which in turn is connected to a condenser placed vertically on the mold, in which, in each mold half, it is located as fluid cooler a liquid with phase change that by gravity returns the condenser fluid to the molds; means for maintaining a circulation of a second cooling fluid through the condenser and means for venting said condenser to the environment. 2a.- System for cooling molds as described in the previous clause, also characterized in that the method for controlling the profile of heat transfer is performed by restricting and orienting the flow of a coolant fluid into the holes practiced in the mold body itself and because said restriction and orientation are produced by at least one capillary groove of different geometries and trajectories, practiced mainly on the outer surface of the hub, whose number and orientation are based on the thermodynamic profile of the article of glass. 3a.- System for cooling molds as described in the previous clauses, further characterized by a multiple head formed by a semicircular groove made in the body of the half mold and a flange of the same shape placed on the groove in the manner of a hermetic cover, which communicates with the condenser by means of at least one connection and, on the other hand, with a plurality of holes made in the body of the mold, in order to feed said holes simultaneously with a back-feed fluid coming from the condenser. 4a.- System for cooling molds as has been described in the previous clauses, further characterized by a means arrangement as described in clause 2, with the addition of a flow control bushing comprising a capillary groove made mainly on the outer surface of the same one and of geometries and diverse trajectories, with a central orifice of diverse dimensions. 5 a.- System for cooling molds as described in the previous clauses, further characterized in that the bushing mentioned in clause 3 also comprises a mark made on both sides and directly related to the capillary slot that facilitates the verification of the required positioning and orientation, and because it is placed in the interconnection of the holes with the integral head, in such a way that it allows the passage of the feedback fluid from the multiple head to the inside of the holes and also allows the exit of the vapors generated by the temperature of the mold, which rise due to its low density towards the condenser, through a central hole. 6a.- System for cooling of molds as has been described in the previous clauses, further characterized by the hub mentioned in clause 3, is capable of providing a precise selective cooling, in each zone of the mold according to the thermodynamic profile required by the glass article features. 7a.- System for cooling molds as described in the previous clauses, also characterized in that the arrangement of media claimed in clause 2, with the addition of a threaded opening made in the semicircular lid, with the possibility of hermetically sealed and eventually discovered, said opening is placed just above each bore in such a way that it allows individual access to each flow control bushing, in order to remove it or adjust it in its direction. 8a.- System for cooling molds as has been described in the previous clauses, further characterized by a provision of means as described in clause 3, with the addition of a thread made in the inner hole of said bushing, such way that allows the fixation of the bushing to carry out the removal, installation or change of direction of the bushing.