Abstract: The invention relates to an impingement dryer and a method for reducing runnability problems caused by gas flows in an impingement dryer for a fibre web, which impingement dryer has gas blowing opening and gas exhaust openings. The fibre web to be dried is supported with a support fabric. The support fabric and the fibre web to be dried are moved in the machine direction inside the impingement dryer past the blowing openings and exhaust openings. At the same time hot gas is blown from the blowing openings toward the fibre web to be dried and gas is removed from the vicinity of the fibre web to the exhaust openings. At least one edge control strip is moved in the machine direction edges of the impingement dryer in front of the blowing openings or the exhaust openings or both. With its aid a desired number of blowing openings or exhaust openings or both are covered and thus their effect is controlled.

Abstract: The invention comprises a method and a system in a paper machine, and also a software product, allowing one or more tools to be generated for indicating the state of the paper production process in terms of energy consumption to the operating staff of the paper machine. This allows continual monitoring of the state of the paper production process and/or its energy efficiency combined with efforts to develop the manners of running the paper machine and its dryer section in a more favourable direction. In one embodiment of the invention, the dry solids content DSC of the press section can be calculated by means of the evaporation amount of the dryer section, the production of finished paper and the final paper moisture as follows: DSC=mpap,d/(mpap,d+mH2O), in which mpap,d is the dry mass flow of the paper web to the dryer section and mH2O is the water mass flow to the dryer section. mH2O is obtained by summing up the mass flow of the water discharged from the dryer section and the evaporated water mass flow.

Abstract: The invention comprises a method and a system in a paper machine, and also a software product, allowing one or more tools to be generated for indicating the state of the paper production process in terms of energy consumption to the operating staff of the paper machine. This allows continual monitoring of the state of the paper production process and/or its energy efficiency combined with efforts to develop the manners of running the paper machine and its dryer section in a more favourable direction. In one embodiment of the invention, the dry solids content DSC of the press section can be calculated by means of the evaporation amount of the dryer section, the production of finished paper and the final paper moisture as follows: DSC=mpap,d/(mpap,d+mH2O), in which mpap,d is the dry mass flow of the paper web to the dryer section and mH2O is the water mass flow to the dryer section. mH2O is obtained by summing up the mass flow of the water discharged from the dryer section and the evaporated water mass flow.

Abstract: A method and an apparatus for arranging exhaust air and supply air in a drying section covered with a hood (14) in a paper machine, having drying cylinders (10) or the like and devices operating by negative and positive pressure. The exhaust air from the devices operating by negative pressure, such as suction rolls (20) and suction boxes is supplied out from the drying section via a first heat recovery tower (22). Substitute air is supplied via this first heat recovery tower to the runnability components (38) operating by positive pressure in the drying section. Substitute air can be additionally supplied via a second separate heat recovery tower (22′) to devices (40, 42) supplying heating air and/or ventilation air. The main portion of the exhaust air from the air space of the hood is supplied via this second heat recovery tower and out from the drying section.

Abstract: The invention concerns a dryer section, comprising at least one dryer group (R) that makes use of single-wire draw and/or twin-wire draw and at least one suction roll (10) with which the web (W) to be dried is in direct contact. The surface construction of the suction roll (10) is of a fine structure so that the web (W) can be passed to run over the suction roll (10) in direct contact with the roll so that the web (W) is not damaged.

Abstract: A method and an apparatus for arranging exhaust air and supply air in a drying section covered with a hood (14) in a paper machine, having drying cylinders (10) or the like and devices operating by negative and positive pressure. The exhaust air from the devices operating by negative pressure, such as suction rolls (20) and suction boxes is supplied out from the drying section via a first heat recovery tower (22). Substitute air is supplied via this first heat recovery tower to the runability components (38) operating by positive pressure in the drying section. Substitute air can be additionally supplied via a second separate heat recovery tower (22′) to devices (40, 42) supplying heating air and/or ventilation air. The main portion of the exhaust air from the air space of the hood is supplied via this second heat recovery tower and out from the drying section.

Abstract: A method and an apparatus for separating solid or drop-like particles from an air flow is provided. The air flows through a separator chamber between an electrode, ion generating means or like particle charging device disposed in the separator chamber, and a grounded collector surface, so that the particles are charged by the charging device and accumulate on the collector surface. The air flows along a substantially spiral path around the charging device in at least a part of the separator chamber so that due to the action of centrifugal force at least a portion of the particles pass toward the grounded collector surface at the periphery of the chamber. A small flow of purified air flows downwardly in a central part of the separator chamber so that it washes the charging device in the separator chamber.

Abstract: A method and device effect controlled uniform temperature drying of a wet web, such as a paper web substantially immediately after formation in a paper machine, without damaging the supporting fabric carrying the web. The web has a central region and first and second border regions. The wet web to be dried is conveyed on a conventional supporting fabric/wire in a first direction generally parallel to the web border regions, and in a hood drying air is blown against the web from the opposite side thereof as the supporting fabric so that the drying air picks up moisture and becomes moistened air. The moistened air is discharged from the volume adjacent the hood, for example is discharged from at least one hood positioned at and encompassing an impingement surface over which the web and supporting fabric pass. Air supplied for blowing against the web is heated to raise its ability to retain moisture.