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EP-4559655-B1 - HOPPER COMPRISING AT LEAST ONE ROTATING HOPPER BODY, AND CALENDERING SYSTEM COMPRISING SUCH A HOPPER

EP4559655B1EP 4559655 B1EP4559655 B1EP 4559655B1EP-4559655-B1

Inventors

  • Locqueville, Frederick
  • CHORIER, Gaël

Dates

Publication Date
20260506
Application Date
20231124

Claims (10)

  1. A hopper (6) comprising a frame and at least one hopper body (14) mounted onto the frame and containing powder (16), said hopper body (14) having an outer wall (23) which defines an internal housing (24) in which said powder (16) is stored, characterized in that the hopper body (14) is mounted rotatable relative to the frame about a longitudinal rotation axis (A-A'), said longitudinal rotation axis (A-A') being a main extension axis of the hopper body (14), and in that the outer wall (23) of the hopper body (14) is provided with a scoop (28), said scoop (28) defining a through opening (30) passing through the outer wall (23) of the hopper body (14), said scoop (28) being configured to collect part of the powder (16) at each rotation cycle of the hopper body (14), at a first position (P1) of the hopper body (14), and to release said part of the powder (16) out of the hopper body (14) through said opening (30), due to gravity, at a second position (P2) of the hopper body (14) which is distinct from the first position (P1).
  2. The hopper (6) according to claim 1, wherein the hopper body (14) is further provided with at least one rotating actuator (26), said at least one rotating actuator (26) being configured to rotate the hopper body (14) relative to the frame.
  3. The hopper (6) according to claim 1 or 2, wherein the cross section of the scoop (28) has a substantially "Z" shape.
  4. The hopper (6) according to any one of the preceding claims, wherein the first and second positions (P1, P2) of the hopper body (14) are shifted by an angle of substantially 90 degrees.
  5. The hopper (6) according to any one of the preceding claims, wherein the hopper (6) further comprises at least one flap (18), said at least one flap (18) being arranged within said hopper body (14), being located at an inner aperture (31) of the scoop (28), and being configured to at least partially close said scoop (28).
  6. The hopper (6) according to any one of the preceding claims, wherein the hopper body (14) further comprises a feeler cap (8), said feeler cap (8) being arranged opposite the scoop (28) of said hopper body (14) and being configured to supply with powder (16) said hopper body (14) upon receipt of a control signal from a control device.
  7. A calendering system (2) comprising two parallel calender rollers (4) and a hopper (6), said hopper (6) being a hopper according to any one of the preceding claims, the two parallel calender rollers (4) defining an interspace (12) between them, the at least one hopper body (14) of the hopper (6) being arranged above the two parallel calender rollers (4) so as to supply with powder (16) said interspace (12) between the two parallel calender rollers (4).
  8. The calendering system (2) according to claim 7, wherein the calendering system (2) further comprises an automatic compensation system (10), said automatic compensation system (10) comprising a control device and at least one ultrasonic sensor (32) connected to the control device and arranged between the at least one hopper body (14) of the hopper (6) and the two parallel calender rollers (4), said at least one ultrasonic sensor (32) being configured to detect the amount of powder (16) supplied by the scoop (28) of the hopper (6) to the two parallel calender rollers (4).
  9. The calendering system (2) according to claim 7 or 8, wherein the hopper (6) comprises two hopper bodies (14) mounted onto the frame and containing powder (16), each hopper body (14) being arranged above the two parallel calender rollers (4) so as to supply with powder (16) said interspace (12) between the two parallel calender rollers (4).
  10. The calendering system (2) according to claim 9, wherein the two hopper bodies (14) are configured to rotate in a desynchronized manner.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a hopper, and to a calendering system comprising two parallel calender rollers and such a hopper. BACKGROUND ART Calendering is a speciality process for high-volume, high quality plastic film and sheet, mainly used for PVC (polyvinyl chloride) as well as for certain other modified thermoplastics. A calendering system operates by passing a material between two contra-rotating parallel rollers to smooth or gloss it, or to produce a film or a sheet. In some particular applications, the material can be an electrically conductive mixture (for example in powder form), and the calendering system participate to fabricate electrodes for electrochemical cells (by forming a film at the outlet of the rollers by calendering). Calendering systems thereby comprising two parallel calender rollers and a hopper, are known in the art. The hopper classically comprises a hopper body which contains powder and is arranged above the two parallel calender rollers so as to supply with powder an interspace between the two parallel calender rollers. The hopper body defines an internal housing at atmospheric pressure in which powder is stored. Such a calendering system may further comprise a device for feeding powder into the interspace between the two calender rollers. Such a device uses mechanical parts (screw, brush, stirrer...) for drain matter. However, the matter may fall into the interspace without any control about the matter which is already present (open loop). Besides, the mechanical parts which are used in such a device introduce a high risk of powder fibrillation. This action can make obstruction and hence causes the system to collapse. In order to overcome the above-mentioned drawbacks, some solutions have been developed in which the calendering system further comprises a vibrating device. The patent document CN 114744145 A discloses for example such a calendering system. The vibrating device is an ultrasonic vibrating device which is provided on an outer side wall of a material guide channel arranged beneath the hopper, and which can adjust the discharge speed and discharge density, to ensure smooth feeding of materials and to allow control of the discharge of the material guide channel. Patent document EP 1 800 775 A1 also discloses such a calendering system in which the hopper comprises a vibrating device provided on an outer side wall of the hopper to control the weight of the electrically conductive mixture in the hopper. However, such vibration calendering systems don't allow to manage powder volume or powder location. Furthermore, there is no compensation in such calendering systems when matter is not regularly fed, and matter holes are likely to appear. A need therefore exists for a hopper for a calendering system, such a hopper allowing to manage powder volume or powder location, while providing automatic compensation system when matter is not regularly fed. SUMMARY OF THE INVENTION The object of the present invention is therefore to overcome the drawbacks of the prior art by providing a hopper for a calendering system which allows to manage powder volume or powder location, while providing automatic compensation system when matter is not regularly fed. According to a first aspect of the invention, there is provided a hopper comprising a frame and at least one hopper body mounted onto the frame and containing powder, said hopper body having an outer wall which defines an internal housing in which said powder is stored ; the hopper body is mounted rotatable relative to the frame about a longitudinal rotation axis, said longitudinal rotation axis being a main extension axis of the hopper body, and the outer wall of the hopper body being provided with a scoop, said scoop defining a through opening passing through the outer wall of the hopper body, said scoop being configured to collect part of the powder at each rotation cycle of the hopper body, at a first position of the hopper body, and to release said part of the powder out of the hopper body through said opening, due to gravity, at a second position of the hopper body which is distinct from the first position. The hopper body thus configured and being provided with such a scoop allows to control the powder feed, and to manage powder volume or powder location. In addition, thanks to this rotary configuration and oscillatory movement of the hopper body with different positions, powder can be easily controlled to flow continuously and homogeneously. In a particular embodiment of the invention, the hopper body is further provided with at least one rotating actuator, said at least one rotating actuator being configured to rotate the hopper body relative to the frame. In another particular embodiment of the invention, the cross section of the scoop has a substantially "Z" shape. In another particular embodiment of the invention, the first and second positions of the hopper body are shifted by an angle