Abstract: The invention relates to a heat-exchanger (10) incorporating circulation tubes (16) for conducting a first heat-transfer medium, end plates (12), and surface-enlarging plate-like fins (14) secured to the outer peripheral surfaces of the circulation tubes and arranged to be contacted with a second heat-transfer medium, the fins being firmly secured to a plurality of circulation tube sections, which extend through registering holes (18) formed in the fins (14). The fins are secured to the tube sections by expanding the tubes so as to enlarge the periphery thereof. The contact surfaces of the fins about the inside periphery of the holes (18) which engage against the circulation tubes (16) are cylindrical and extend parallel to the longitudinal axis of the circulation tubes over at least a greater part of the axial extent of the holes, which affords stable attachment and good heat-transfer properties.

Abstract: According to the invention there is provided an arrangement which can be used in particular in a media-mixing nozzle assembly intended for use with or to be incorporated in a contact reactor. The nozzle assembly enables a first medium to be mixed with a second medium. This medium mixture is used to clean a contaminated medium fed to the contact reactor, by bringing the contaminated medium into contact with the medium mixture, this mixture containing an absorbent which is capable of reacting with the contaminants in the contaminated medium. The first medium and the second medium are supplied under overpressure to a mixing chamber provided in the nozzle assembly and located upstream of the exit orifice of a nozzle.

Abstract: A gas cleansing arrangement comprising a vessel (1) partially filled with liquid (32) and a gas distribution means (14) beneath the liquid surface (34). The gas distribution means (14) comprises obliquely and downwardly extending distribution pipes (26) with upwardly facing inlet openings (64) for contaminated gas and a lower opening (22). The inlet openings are each connected to a venturi device (28) having an outlet opening (31) and suction openings (29) facing the liquid (32). In use, pressurized gas urges an inner liquid surface (46) downwards in the distributor means (14), until the liquid surface (46) reaches and exposes the uppermost inlet opening or openings (64). The gas is then forced through respective venturi device (28) at a pressure drop corresponding to the height difference (h) between the inner liquid surface (46) and respective outlet opening (31).

Abstract: Method for cleansing gas from solid, liquid and/or gaseous contaminants, by bubbling the gas through a liquid bath (32), and by introducing the incoming gas into a distribution means (14) and causing the gas to pass in part-streams through a multiple of inlet orifices (64) located at progressively increasing depths beneath the surface (34) of the liquid (32). With increasing inlet pressure an increasing number of inlet orifices (64) are utilized for an increasing number of part-streams. The gas flow is passed from respective inlet orifices (64) through connecting means (24, 26, 28) to outlet orifices (31) located at a considerably higher height level (h) than corresponding inlet orifices (64). The gas flow is caused to flow out through venturi nozzles (28) and/or to strike against impinger or striking surfaces (39) with a minimum pressure drop corresponding to said height differential (h).

Abstract: The invention relates to a method and an arrangement for mixing a dry or substantially dry powder material (2) with a liquid to form a slurry (4), while using a vessel (7) which contains the liquid and which is provided with agitating means (5), and in which the powder material (2) is charged to the liquid continuously or intermittently. The powder material (2) is charged to the liquid (9) via a pipe (8). The end (8a) of the pipe through which the powder material is discharged is located at a distance beneath the surface (9a) of the mixture.

Abstract: The present invention relates to an arrangement in the drying section of a paper machine, preferably the drying section of a cylinder drying machine, for enabling the shrinkage and stretch, of a paper web to be controlled transversely to the direction of web travel with the aid of straps, preferably two, each of which passes through the drying section, and is positioned adjacent to an edge of the paper web for the purpose of imparting to the web a force which is oriented at right angles to the direction of web travel. An adhesive layer is applied to adhere the straps and the edge of the web.

Abstract: The invention relates to a method and an arrangement for enabling a contaminated medium to be cleansed in a contact reactor by introducing thereinto a pulverulent absorption material capable of reacting with contaminants in the medium, the medium and the absorption material being mixed together in the contact reactor over a period of time in which contaminants react with the material, therewith to absorb on and react with individual particles in the pulverulent absorption material.

Abstract: The invention relates to an arrangement for transporting disintegrated solid particles, in which the particles are transported by a quantity of air placed under an over pressure. The weight ratio of the particle/aix mixture lies within a range at which particle transportation gives rise to migrating particle agglomerations. Transportation of the particles is terminated in a particle agglomeration equalizing arrangement, from where the particles are transported further in the form of a particle/air mixture which has been equalized in time. Particle transportation is effected by at least two stages. A first stage in which the weight ratio of the particle/air mixture is greater than 15, and a second stage in which the weight ratio of the particle/air concentration is greater than 5 and lower than the weight ratio of the particle/air mixture in the first stage. The arrangement is used for transporting powdered coal to a powdered-coal burner connected to a combustion furnace.

Abstract: The invention relates to a method and to an arrangement for controlling the respective conduction times of two directionally opposed electrical devices (9,10) which are mutually connected in parallel and permit current to pass therethrough solely in one direction, and which also permit current (I.sub.2) to pass through the primary winding (2) of a transformer during a respective half-period of an A.C. voltage (U.sub.1) applied to the primary winding, this control being effected so that the magnetizing current through the transformer can be advantageously minimized and/or held beneath a given limit value when an asymmetric load (4,5) is applied to the secondary side (3) of the transformer. A magnetizing current in the primary winding corresponding to the load (5) of the secondary winding (3) is controled through the agency of different conduction times of the two directionally opposed devices (9,10).

Abstract: The present invention relates to an electrostatic precipitator (2) which comprises mutually adjacent discharge electrodes (3a) and collecting electrodes (4a), and a voltage source which delivers to the electrodes a d.c. current of high voltage so as to generate in the space (5) between the electrodes an electrostatic field which imparts an electrical charge to the solid particles and/or liquid droplets entering the space (5), such that the particles/droplets are attracted primarily to the collecting electrodes (4a). A plurality of electrodes are formed and positioned in a manner to provide a self-supporting structure which is flexurally rigid in all directions. The electrodes are positioned with the aid of beams (20, 21, 22) to define the aforementioned space (5), together with wall sections (2a, 16).

Abstract: The invention relates to a method and an arrangement for cleansing a flow of hot contaminated gas (1), in which the contaminants comprise both dust particles and gaseous condensable contaminants. The gas is cooled in a heat exchanger in a first stage (2) to a temperature which lies above the temperature at which the gaseous contaminants begin to pass into their respective liquid phases. The gas is then cooled further, in a second stage (4), by mixing the gas with a colder gas flow (5), so as to bring the temperature of the gas to a level suitable for subsequent extraction of contaminants in a first dust separator (3, 3a), while condensing part of the gaseous contaminants present. Condensed contaminants are bound by adsorption and/or absorption to dust particles collected in the first dust separator (3, 3a).

Abstract: An arrangement in a heat-exchange unit comprising heat-emitting or heat-absorbing means which are exposable to an incoming medium flow entering the unit and which are effective to change the energy content of incoming medium flow to form an exiting medium flow which leaves the unit. A further medium flow is delivered to the incoming medium flow in the vicinity of the unit, this further medium flow being so directed as to force the incoming medium flow through the unit with the aid of an ejector effect.

Abstract: The invention relates to an arrangement in drying sections intended for drying web material (2) which is arranged for movement through the drying section while supported by a plurality of air streams which impinge on the undersurface of the web and which extend parallel with, or substantially parallel with a plane allotted to the web, each of these air streams being given an exiting velocity and direction, via nozzle-like exit apertures (11, 11a) formed in a blow box (7), such as to maintain the web (2) in a suspended state above the blow box (7). Arranged in that end-part (8) of a blow box through which a flow of supply air (7a) is introduced thereinto is a means (20) operative in reducing and/or eliminating and/or over-compensating the influence of the velocity vector (7a') of the flow of supply air (7a) on the direction in which the air streams exit from the blow box through nozzle-like exit apertures (11,11a) formed therein and located adjacent the end-part (8) of the blow box.

Abstract: A method and apparatus for producing a continuous web of material (36) on an endless belt (24). Fibers suspended in a carrier gas are transported from a transport conduit (12) through a transition part (38) of zig-zag configuration, having cross-section which tapers or narrows in the flow direction. Arranged at the outlet aperture of the transition part is a coarse-particle separator means (22) which incorporates a curved, convex surface (60), an accept outlet (48), and a reject outlet (54). The carrier gas is deflected around the convex surface, as a result of the ensuing Coanda Effect, and transports acceptable fine fibers to the accept outlet (48), while coarse reject particles, due to their greater kinetic energy, pass in a straighter path to the reject outlet (54). The accept outlet leads directly to a distribution chamber (52) which is located above the endless belt (24), and opposite which there is provided a suction box (32) for extraction of the carrier gas.

Abstract: In a method of ventilating rooms, fresh air is introduced into the room at one or several places at floor level by means of diffuse air supply, and the room air is exhausted at the ceiling level of the room. One or several jets of fresh air (2a, 2b) are blown at high velocity into an induction chamber (4) thereby sucking surrounding air (3) into the induction chamber and becoming mixed therein with the surrounding air sucked into the induction chamber. The mixed air from the induction chamber (4) is introduced essentially horizontally into the room to be ventilated. Into the induction chamber (4) surrounding air is sucked in which consists of air (3) from the room to be ventilated, this air being sucked into the induction chamber from a level in the room which is higher than the level at which the mixed air is introduced into the room. The mixed air is introduced into the room by means of diffuse air supply.

Abstract: A modular frame arrangement suspendable from the ceiling of a room is proposed for receiving filters having fluid seals for clean room ceilings, which consists of structural rails having U-section channels for receiving the fluid, the rails being provided with a central web. Lying parallel to the ceiling, the webs of the rails and the central webs are constructed as hollow sections, the hollow section of the web being formed of two hollow chambers and a T-section groove lying between these hollow chambers. For connection of the rails, connection members are provided which have a square central part and integral arms offset in height at the lower side. The connection members are inserted with their arms in the rails so that the respective U-section channels are extended around the corner.

Abstract: Method and arrangement for varying a d.c. voltage occurring between electrodes of an electrostatic dust separator, said voltage being generated by a number of frequency-related pulses together forming a pulse train. A mains voltage (50 Hz) is fed via valve organs (8, 8a) controlled by a control circuit (7) to a transformer (T), the current pulses of which are full-wave rectified (9) and are connected to electrodes (10) of the dust separator. The control circuit (7) is so arranged as to extinguish an even number, being two, four or more, of pulses from the mains voltage between two consecutive pulses supplied to the electrodes of the dust separator.

Abstract: The invention relates to a media mixing nozzle assembly (10'), intended for use in a contact reactor to enable a first medium (A) to be mixed with a second medium (B), where the mixed medium is to be used for cleansing a contaminated medium fed to the contact reactor, by bringing the contaminated medium (5a') into contact with the medium mixture (C) containing an absorption material which reacts with the impurities contained by the contaminated medium. The first medium (A) and the second medium (B) are supplied, under overpressure, to a mixing chamber (13') of the nozzle assembly. This chamber (13') is connected with a mixture conveying channel (20) having a cross-section which diverges from the chamber (13') in a manner such that the pressure within the exit orifice (20a) of the channel substantially coincides with the pressure surrounding (21) the channel orifice.

Abstract: The present invention relates to an arrangement and a method for controlling or regulating shrinkage and/or stretching of a paper web transversely to the transport direction thereof in a drying section of a paper machine, this drying section having the form of a cylinder dryer (6) and/or a fan dryer. At a point in the drying process at which the paper web exhibits a dry solids content of at most 75%, the paper (10) is subjected to an outwardly directed force which is forced to act in the edge portion (10a, 10b) of the web. The forces are caused to act adjacent parallel edge portions (10a, 10b) of the paper web and are directed away from each other. The magnitude of these forces is selected so that they fall beneath shrinkage forces occurring momentary on the paper web at the dry solids content in question by at most 50%.