EP3815896A1

EP3815896A1 - Heating device for calender cylinders

Info

Publication number: EP3815896A1
Application number: EP19206499.6A
Authority: EP
Inventors: Patrizio Petrelli
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2021-05-05
Anticipated expiration: 2039-10-31
Also published as: EP3815896B1; EP3815896C0

Abstract

A heating device for calender cylinders, comprising a core cylinder (1) around which a cylinder (2, 3) is arranged which is adapted to support a plurality of infrared heating elements (6), the core cylinder (1) and the cylinder (2, 3) adapted to support the infrared heating elements (6) being accommodated in a fixed manner inside a rotating calender cylinder (5).

Description

The present invention relates to a heating device for calender cylinders. More particularly, the invention relates to a heating device that has an effective temperature control.
As is known, in calender cylinders the commonly used heating method is the one with diathermic oil.
As is known, the calender is a machine tool constituted by two or more rotating cylinders, made of steel or cast iron, between which the material to be worked is made to pass. It is normally used in the rubber, paper, textile and metallurgical industry.
Calender cylinders are normally heated by means of diathermic oil, which is heated by means of electric resistors or gas-fired boilers. As an alternative, calenders can be of the direct electric heating type.
The oil-based heating system forces the installation of pumping assemblies, high-pressure circuits, hydraulic control units, rotary joints, equipment which requires periodic maintenance and therefore consequent costs, in addition to possible machine downtimes for said maintenance.
Furthermore, in calenders heated with diathermic oil there is difficulty in adjusting the temperature along the length of the cylinder, since it is very complicated to be able to have regions at differentiated temperature along the length of the cylinder.
Moreover, the drawback in calenders with diathermic oil heating is that they do not have high precision and uniformity of heating along the extension of the cylinder.
The aim of the present invention is to provide a heating device for calender cylinders that has low costs and complexity with respect to cylinders with diathermic oil heating.
Within this aim, an object of the present invention is to provide a heating device for calender cylinders that allows extremely simple temperature control with multiple temperature adjustment regions along the length of the cylinder.
Another object of the present invention is to provide a heating device for calender cylinders in which high precision and uniformity of heating along the length of the cylinder can be achieved.
Another object of the present invention is to provide a heating device for calender cylinders that is highly reliable, relatively simple to provide and at competitive costs.
This aim, as well as these and other objects which will become better apparent hereinafter, are achieved by a heating device for calender cylinders, characterized in that it comprises a core cylinder around which a cylinder is arranged which is adapted to support a plurality of infrared heating elements, said core cylinder and said cylinder adapted to support said infrared heating elements being accommodated in a fixed manner inside a rotating calender cylinder.
Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the heating device according to the invention, illustrated by way of nonlimiting example in the accompanying drawings, wherein:

Figure 1 is an exploded perspective view of a calender cylinder with the heating device according to the present invention;
Figure 2 is a cutout perspective view of the calender cylinder with the heating device according to the present invention;
Figure 3 is a longitudinal sectional view of the calender cylinder with the heating device according to the invention;
Figure 4 is a front view of the calender cylinder with the heating device according to the invention.

With reference to the figures, the heating device according to the invention comprises a core cylinder 1 around which two flanged half- shells 2 and 3 are arranged which constitute a cylinder and are adapted to be coupled to each other and spaced from the core cylinder 1 by means of spacers 4.
The coupling between the core cylinder 1 and the external flanged half- shells 2 and 3 forms an assembly that is adapted to be fixed inside a calender cylinder 5 which rotates about said assembly.
Conveniently, the flanged half- shells 2 and 3 are provided externally with infrared heating elements 6 which are arranged on the external surface of the flanged half- shells 2 and 3, preferably in a position that is aligned with the longitudinal axis of the flanged half- shells 2 and 3.
Conveniently, the flanged half- shells 2 and 3 are provided with a plurality of holes 7 on their surface.
The flanged half- shells 2 and 3 are furthermore provided with a plurality of fins 8 which preferably extend along the entire length of the flanged half- shells 2 and 3.
The presence of the infrared heating elements allows to heat the calender cylinder 5, which is arranged externally and concentrically to the core cylinder 1, effectively and with reduced costs by virtue of the absence of oil pumping systems, hydraulic control units, high-pressure circuits and rotary joints.
Temperature control is extremely simple, i.e., with the possibility to have multiple temperature adjustment regions along the length of the cylinder, by virtue of the arrangement of the heating elements 6 along the external surface of the flanged half- shells 2 and 3.
Furthermore, it is possible to have high precision and uniformity in heating by virtue of the presence of temperature adjustment probes arranged on the outside of the cylinder.
The invention also relates to a calender cylinder provided with a heating device according to the invention.
In practice it has been found that the heating device according to the invention achieves fully the intended aim and objects, since by being arranged inside a calender cylinder it allows to heat the calender cylinder with infrared heating elements which simplify maintenance operations and in general the complexity that is instead required by calender cylinders heated with diathermic oil.
The heating device thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the accompanying claims.
All the details may furthermore be replaced with other technically equivalent elements.
In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.
Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

A heating device for calender cylinders, characterized in that it comprises a core cylinder (1) around which a cylinder (2, 3) is arranged which is adapted to support a plurality of infrared heating elements (6), said core cylinder (1) and said cylinder (2, 3) adapted to support said infrared heating elements (6) being accommodated in a fixed manner inside a rotating calender cylinder (5).
The heating device according to claim 1, characterized in that said infrared heating elements (6) are arranged on the external surface of said cylinder (2, 3) arranged externally with respect to said core cylinder (1).
The heating device according to claim 1 or 2, characterized in that said infrared heating elements (6) are arranged along the longitudinal axis of said core cylinder (1).
The heating device according to one or more of the preceding claims, characterized in that said cylinder (2, 3) which supports said infrared heating elements (6) is provided with a plurality of fins (8) which are extended along the entire length of said cylinder (2, 3).
The heating device according to one or more of the preceding claims, characterized in that said cylinder (2, 3) which supports said infrared heating elements (6) is constituted by two flanged half-shells (2, 3).
The heating device according to one or more of the preceding claims, characterized in that said cylinder (2, 3) which supports said infrared heating elements (6) is provided with a plurality of holes (7).
The heating device according to one or more of the preceding claims, characterized in that it comprises temperature adjustment probes arranged outside said cylinder (2, 3).