Abstract: The present invention provides a doctor device for metering and/or equalizing a liquid-to-pasty medium applied to a running surface, wherein in the case of direct application the surface is a running paper web, paperboard web or other fibrous web and in the case of indirect application a transfer element which transfers the application medium to the fibrous web. The doctor device has a holder arranged on a support beam for accommodating a doctor element used for the metering and/or equalizing. The holder has a first fixed support face bar and a second moving support face bar, wherein to open and close the holder the second support face bar is displaceable respectively away from the first support face bar or toward it such that in the closed state of the holder the doctor element is fixed from the outside and in the open state of the holder it is released.

Abstract: The present invention provides a doctor device for metering and/or equalizing a liquid-to-pasty medium applied to a running surface, wherein in the case of direct application the surface is a running paper web, paperboard web or other fibrous web and in the case of indirect application a transfer element which transfers the application medium to the fibrous web. The doctor device has a holder arranged on a support beam for accommodating a doctor element used for the metering and/or equalizing. The holder has a first fixed support face bar and a second moving support face bar, wherein to open and close the holder the second support face bar is displaceable respectively away from the first support face bar or toward it such that in the closed state of the holder the doctor element is fixed from the outside and in the open state of the holder it is released.

Abstract: The invention relates to a web-guiding device comprising at least one directing element (10) for guiding a web in a contactless manner in a machine that is used for producing and/or treating a moved web of material (1), especially a paper or cardboard web. Said directing element (10) is provided with a directing surface (12) that is made at least in part of air-permeable porous material (14) which can be impinged upon by compressed air so as to form an air cushion (18) between the directing surface (12) and the moved web of material (1) via the air (16) flowing through said porous material (14). The directing surface (12) is divided into at least one web transfer zone (2, 4) and a web-guiding zone (3) along the direction of movement (2) of the web of material. Said zones (2, 4; 3) are embodied so as to allow for a different air throughput.

Abstract: A machine for the production and/or converting of a material web, especially a paper or carton web, such as a coating machine for single sided or two-sided application of liquid or viscid coating medium onto a moving web by way of at least one application device. At least one carrier surface, or partial surface, and/or at least one area or partial area, of the machine that is exposed, or could be exposed, during the operation and/or during start-up of the machine and/or during slow-down of the machine and/or during at least an exceptional operational condition of the machine to the medium is a focus of the present invention. Application medium, that is used in the production or converting process, and/or is subjected to another contamination hazard, is formed by or furnished with a permanent or temporary, protective layer, also referred to as barrier layer, that is applied to the carrier surface.

Abstract: A device designed for coating a material web with a coating medium includes a coater, a metering/smoothing device positioned downstream of the coater in the direction of feed of the material web, at a certain distance from the coater, and a support roll around which the material web is guided. Moreover, the material web is guided around the support roll only in the area of the metering/smoothing device, and it traverses essentially in a straight line between the coater and the support roll. In accordance to a first aspect of this invention, a support arrangement supports the material web in the straight web section between the coater and the support roll. In accordance to a second aspect of this invention, devices are provided which stabilize the material web in the area where the web traverses in a straight line.

Abstract: An apparatus for direct or indirect application of at least one liquid or pasty medium onto a traveling material web, notably of paper or cardboard, includes at least one applicator for the medium. Coordinated with the applicator is a backing roll for receiving the medium in the indirect application or for carrying the material web in the direct application. The applicator includes a coating doctor and, arranged a distance from the coating doctor in a direction opposite to the direction of rotation of the backing roll, a second doctor element. The second doctor element bounds, with the coating doctor, a coating chamber for the medium. The coating doctor and the second doctor element are retained on a common, substantially rigid doctor bed and bound together with the backing roll surface and the doctor bed surface the coating chamber. At least one feed line for feeding the medium to the coating chamber is provided in the common doctor bed.

Abstract: A method and apparatus for coating a traveling layer of material, in particular paper and/or cardboard. An applicator implement applies a predetermined and proper amount of a liquid or pasty medium onto an outer surface of a first rotating applicator roller which in turn transfers the liquid or pasty medium onto a first side of the moving layer of material just as it is moving through a press nip. A second layer of coating medium is applied indirectly with a second applicator implement onto an outer surface of a second rotating applicator roller from where it is transferred onto the previously coated side of the moving material layer while the first coat of coating medium is still wet.

Abstract: An apparatus for direct or indirect application of at least one liquid or pasty medium onto a traveling material web, notably of paper or cardboard, includes at least one applicator for the medium. Coordinated with the applicator is a backing roll for receiving the medium in the indirect application or for carrying the material web in the direct application. The applicator includes a coating doctor and, arranged a distance from the coating doctor in a direction opposite to the direction of rotation of the backing roll, a second doctor element. The second doctor element bounds, with the coating doctor, a coating chamber for the medium. The coating doctor and the second doctor element are retained on a common, substantially rigid doctor bed and bound together with the backing roll surface and the doctor bed surface the coating chamber. At least one feed line for feeding the medium to the coating chamber is provided in the common doctor bed.

Abstract: The invention relates to an application unit for the direct or indirect application of a liquid or pasty medium (12) onto a moving material web, in particular consisting of paper or board, comprising a dosing gap formed as a free jet nozzle, the dosing gap being formed between a leading lip (4) and a trailing lip (8), and at least one feed channel (14) leading to the dosing gap. The application unit is characterized in that the dosing gap is subdivided in a comb-like manner and has a plurality of defined through-gaps (32) for the liquid or pasty medium (12).

Abstract: An apparatus for applying a liquid or pasty medium, i.e. a coating medium onto a moving material web, in particular consisting of paper or board. At least one application unit applies the medium. A roll associated with the application unit receives the medium. The application unit has an application doctor blade and has a cleaning doctor blade which is arranged at a distance from the application doctor blade in the direction opposite the direction of rotation of the roll. The cleaning doctor blade together with the application doctor blade defines an application chamber for the medium. In order to prevent the collection and build-up of fibers, foreign bodies and similar particles upstream of or on the entrance side of the cleaning doctor blade, as far as possible, the cleaning doctor blade is equipped with a blade bar which is supported by a holder.

Abstract: A method for at least one-sided coating of a material web with an application medium is performed by a two-element applicator device having at least one applicator roll and a counter element defining a gap through which the material web is conveyed. The method includes the steps of pre-metering the application medium onto the applicator roll and transferring the application medium onto the material web in the gap. Pre-metering of the application medium to the applicator device is performed by at least one free jet.

Abstract: A device for predosing coating composition on a traveling web of paper. A guide member extends obliquely toward the web. Downstream in the path of the web past the guide member, a doctor element is supported spaced from the tip of the guide member for defining a pressure space between the a guide member and the doctor element. Coating composition is fed through a feed channel between the guide member, on the one hand, and the doctor element and the supports for the doctor element up to the pressure space, on the other hand. An exit slot from the pressure space between the guide member and the web is defined at the tip of the guide member. The guide member has a guide surface down from the tip of the guide member, on the side of the guide member away from the doctor element which faces generally toward the web. The guide surface defines a return channel for coating composition that has moved out of the pressure space and through the slot.