A device introduced in a horizontal calender for processing rigid polymer sheets.

Description

1 / 8 A device introduced in a horizontal calender for processing rigid polymer sheets. Field of application

[001] This utility model patent relates to a practical and innovative horizontal calender model for processing rigid polymer sheets, belonging to the field of extrusion machines with calender, for the manufacture of rigid plastic sheets such as PET, Polypropylene, Polycarbonate, PVC or Polystyrene, for use more precisely in the cooling and smoothing of the sheets coming from the extrusion head, and to which an original constructive arrangement has been given, with a view to improving its use and performance in relation to other models usually found on the market.

[002] More specifically, it is a calender consisting of two horizontal cylinders and a third of smaller diameter positioned at a level above and behind the intermediate cylinder, i.e., diagonally.

[003] This is, therefore, a model developed with perfection and efficiency, in order to offer a calender for processing rigid polymer sheets, providing great reliability to what it is intended for, both for its functional characteristics and for the durability of the product.

[004] It is also the objective of this application to present a calender model for processing rigid polymer sheets with low costs for its industrial feasibility, but combined with the requirements of robustness, safety and practical utility, thus offering the consumer public an additional option in the market of similar products, which unlike the Petition 870240108870, dated 12 / 20 / 2024, page 8 / 21 2 / 8 of the usual models, it offers numerous possibilities and benefits to its users, making it a widely accepted model in the plastic sheet industry. Disposition history

[005] As is known, especially by those skilled in the art, in the manufacture of rigid polymer sheets, such as PET, Polypropylene, Polycarbonate, PVC or Polystyrene, the material from the extrusion head is sent directly to a calender for cooling and smoothing.

[006] The cylinders used in the extrusion line generally have a coolant circulating inside them, the temperatures of which are controlled, since the sheet must be cooled gradually until it is sufficiently solidified to continue the process. This cooling is fundamental to the process and therefore the temperature of the circulating fluid in the cylinders must be rigorously controlled.

[007] For example, the material exiting the die needs to be between 215°C and 250°C and between 155°C and 177°C when passing through the intermediate roller, which is a temperature where the Polypropylene is still flexible enough to go around the cylinder, and between 100°C and 120°C when exiting the last cylinder, which is a temperature below the melting point of PP and appropriate for the sheet to be pulled by rubber rollers. State of the art

[008] The state of the art anticipates a calender consisting of three cylinders of the same diameter positioned vertically or at an angle of 35°, mounted in a rigid structure, where the cylinders have fluid circulation. Petition 870240108870, dated 12 / 20 / 2024, p. 9 / 21 3 / 8 soda.

[009] In this equipment, the molten material is introduced between the upper and intermediate rollers and then rotates 180° around the intermediate roller, changing direction, then passes between this intermediate roller and the lower roller, then rotates 180° around the lower roller, reversing direction again, and finally is sent to rubber traction rollers, proceeding to other stages of the process. Weak points of the state of the art

[010] The technical and functional problems of prior art plastic calenders, namely, in vertical or 35° inclined calenders, the plastic sheets have reduced contact with the cooling cylinder, covering only 180 degrees of said cylinder, thus not making the most of its cooling area. Summary of the provision

[011] It was with these drawbacks in mind that, after numerous research and studies, the inventor, a person connected to the field, created and developed the object of this patent, designing a calender for processing rigid polymer sheets in which not only the mechanical and functional qualities were considered in the design of its manufacture, but also the shape, arrangement and location of its parts and components which, correctly positioned, brought about an increase in efficiency without incurring any burden.

[012] The proposed solution to address the low efficiency of prior art calenders is an innovative configuration with two horizontal cylinders and one cylinder offset above, these cylinders being asymmetrical of different Petition 870240108870, dated 12 / 20 / 2024, page 10 / 21 4 / 8 diameter.

[013] This change significantly improves plasticization and production yield, with the sheet now covering up to 225° of the cylinder.

[014] Thus, the present patent was designed with the aim of obtaining equipment with the fewest possible number of parts, conveniently configured and arranged to allow the calender for processing rigid polymer sheets to perform its functions with unparalleled efficiency and versatility, without the aforementioned drawbacks.

[015] Its innovative design allows for an excellent level of functionality, offering a calender model for processing rigid polymer sheets that has great durability, having been created primarily to solve the inconveniences caused by three-cylinder vertical calenders.

[016] It is therefore understandable that the equipment in question is extremely simple in its construction, and therefore easy to manufacture, yet it achieves excellent practical and functional results, offering an innovative construction compared to known models. Brief description of the layout drawings

[017] To complement the present description in order to obtain a better understanding of the characteristics of the present invention and in accordance with a preferred practical embodiment thereof, a set of drawings is attached to the description, where, in an exemplary, though not limiting, manner, the following is represented:

[018] FIG. 1 - Shows a side view of Petition 870240108870, dated 12 / 20 / 2024, page 11 / 21 5 / 8 extrusion line with horizontal calender for processing rigid polymer sheets.

[019] FIG. 2 - Shows a top perspective view of the extrusion line with horizontal calender for processing rigid polymer sheets, without representation of the conveyor belt after the calender.

[020] FIG. 3 - Shows a side view of the detail of the horizontal calender for processing rigid polymer sheets, now in question.

[021] FIG. 4 - Shows a top perspective view of the horizontal calender for processing rigid polymer sheets, now in question.

[022] FIG. 5 - Shows a side view of the horizontal calender for processing rigid polymer sheets, with the representation of the material exiting the extrusion die and passing through the cooling cylinders. Detailed description of the incorporation

[023] In accordance with what is illustrated in the figures above, the ARRANGEMENT INTRODUCED IN A HORIZONTAL CALENDER FOR PROCESSING RIGID POLYMER SHEETS, the subject of this patent, integrates an extrusion line for the production of polymer sheets and has the function of cooling the material coming from the extrusion die.

[024] Said extrusion line (1) comprises an extruder (2) followed by the laminating calender (3), the subject of this patent application, which performs the smoothing and cooling of the sheet and directs it to the conveyor belt (4) which precedes the traction device. Petition 870240108870, dated 12 / 20 / 2024, page 12 / 21 6 / 8 (5), which in turn is followed by the accumulator (6), which precedes another traction device (7) and ends in a winder (8).

[025] More specifically, the said laminating calender (3) is positioned under the extrusion die (9) which is supported by an interconnecting structure (10).

[026] Said laminating calender (3), the subject of this patent application, is a smoothing and cooling unit, specially manufactured for processing rigid plastic sheets.

[027] The rolling mill (3) consists of a rigid metal structure (11), of sheets and profiles joined by welding, which has a front cylinder (12), an intermediate cylinder (13) and a rear cylinder (14), the front cylinder (12) having a smaller diameter than the others.

[028] The front cylinder (12) and the intermediate cylinder (13) are positioned horizontally at the same level and the rear cylinder (14) is in a higher position than the two.

[029] The surfaces of the three cylinders are ground and fitted with layers of bimetallic stainless steel with a hardness of 55 HRC, ground with a polished and mirror-finished hard chrome bath with a roughness of 0.01 micron Ra.

[030] The closing of said cylinders is provided by four hydraulic cylinders, with adjustable pressure. Said hydraulic cylinders are actuated by means of solenoid valves and selector switches.

[031] The distances between the straightening cylinders are obtained by micrometric precision mechanisms, Petition 870240108870, dated 12 / 20 / 2024, page 13 / 21 7 / 8 of the thread and wedge, which allow for hundredth-of-a-day adjustments.

[032] The bearings (16) of the three straightening cylinders are of the detachable type, with special high precision, self-centering and fully sealed bearings.

[033] The three cylinders are driven by geared motors (17) coupled directly to the cylinder shaft, controlled by a frequency inverter. The calender's up-down system is included in this item.

[034] There is also a complete individual cooling system (18) for each rolling cylinder, for temperature control, with centrifugal pumps, valves, filters, heaters, heat exchangers, pressure gauges, pressure switches, thermostats and temperature regulator which, when mounted with other electrical controls on an operating panel, provide a wide range of processing operations. Machine operation up to the calender.

[035] The plastic raw material (granules) is melted inside the extruder (2) and the sheet forming process (19) begins at the exit of the Flat-Die head.

[036] It exits the transformation process in a liquid state and to transform into a rigid sheet it needs a thermal shock through contact with a cold surface, and for this it spreads through the extremities and around the three cooled cylinders, which work together.

[037] After the material is cooled by the laminating calender (3), it goes to the conveyor belt (4), then to the traction device (5), finishing the process in coil form.

[038] The subject of this patent application Petition 870240108870, dated 12 / 20 / 2024, page 14 / 21 The 8 / 8 configuration provides greater contact between the rigid plastic sheet and the cylinder's cooling surface, maintaining a larger contact area compared to a vertical calender. This results in a higher quality plastic sheet with less thickness variation, as well as better plasticization due to the longer cooling contact time. Furthermore, it improves the efficiency of the machine's cooling system, thus generating energy savings.

[039] It is understood that when the present utility model is put into practice, modifications may be introduced with regard to certain details of construction and form, without this implying a departure from the fundamental principles that are clearly substantiated in the claims, it being understood that the terminology used was for the purpose of description and not limitation. Petition 870240108870, dated 12 / 20 / 2024, page 15 / 21

Claims

1 / 1 CLAIM: 1- The arrangement introduced in a horizontal calender for processing rigid polymeric sheets, the subject of this patent application, integrates an extrusion line, whose state of the art anticipates calenders with verticalized structures with cylinders of the same diameter aligned vertically, and unlike these models, the subject of this patent application is characterized by being constituted from a rigid metallic structure (11), of sheets and profiles joined by welding, which has a front cylinder (12), an intermediate cylinder (13) and a rear cylinder (14), noting that the front cylinder (12) has a smaller diameter than the others, with the front cylinder (12) and the intermediate cylinder (13) being positioned horizontally at the same level and the rear cylinder (14) in a higher position than the other two, with the surfaces of the three cylinders being ground and provided with layers of bimetallic stainless steel with a hardness of 55 HRC,The cylinders are ground with a polished and mirror-finished hard chrome plating to a roughness of 0.01 micron Ra, and the cylinder closures are provided by four hydraulic cylinders with adjustable pressure. Petition 870240108870, dated 12 / 20 / 2024, pages 16 / 21

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