Abstract: An apparatus for cleaning the surface of a backing roll in a coater or a calender roll, wherein the roll is cleaned by spraying water on it and then scraping the water away from the surface or the roll with a doctor blade. Splashing of the water accumulating in front of the doctor blade is prevented by a rubber sheet extending down close to the tip of the blade, or alternatively, using a guide blade mounted in front of the doctor blade. The rubber sheet preceding the doctor blade isolates the water pond formed in front of the doctor blade from the surface of the roll, so that the rotational movement of the roll cannot induce turbulence and splashes.

Abstract: A method and apparatus for cleaning the surface of a backing roll in a coater or a calender roll. The roll is cleaned by injecting steam from a steam injection chamber against the roll surface at a 15.degree. angle counter to the rotational direction of the roll. Steam impinging on the surface performs effective removal of accumulated dirt and the detached dirt is carried away on the web without a deleterious effect on the quality of the web. Steam injected against the roll is vacuumed away from the roll surface via a suction chamber, whereby the cleaning steam is prevented from escaping to the surroundings.

Abstract: A method and apparatus for cleaning the surface of a backing roll in a coater or a calender roll. The roll is cleaned by injecting steam from a steam injection chamber against the roll surface at a 15.degree. angle counter to the rotational direction of the roll. Steam impinging on the surface performs effective removal of accumulated dirt and the detached dirt is carried away on the web without a deleterious effect on the quality of the web. Steam injected against the roll is vacuumed away from the roll surface via a suction chamber, whereby the cleaning steam is prevented from escaping to the surroundings.

Abstract: A steam box includes a system for distributing steam onto a web being calendered. At least one valve is connected to the steam distributing system for controlling the flow of steam onto the web. The steam box also has element for feeding hot steam to the valve. Each valve has at least three steam channels, namely an inlet channel for feeding the steam to the valve, an outlet channel of the valve for feeding the steam onto the web and a recirculation channel for recirculating the steam. The valve also has a check element for controlling and dividing the incoming steam flow from the inlet channel between the outlet channel and recirculation channel of the valve, and a return pipe connected to the recirculation channels of the valves, capable of routing the steam directed to the recirculation channel of the valve to e.g., the condensate return line of the steam distributing system.

Abstract: A method and an apparatus for severing a perforated web involves clamping the web (4) by two clamping members (6, 7) extending essentially transversely over the web (4) against an anvil (1) placed on the opposite side of the web (4) so as to leave a perforated line (5) of the web aligned between the clamping members (6,7). The clamped web is then tensioned by allowing a tensioning member (2) located between the clamping members (6,7) to expand toward a backing bight (20, 21) formed behind the web (4) thus causing the web (4) to be severed at the perforation (5) with the help of tensile stress.