Abstract: Inlet bell for centrifugal fans having an impeller (15, 24) with a cover plate (14, 23), the inlet bell opening into the cover plate with an intervening gap (I) for recirculation air, wherein the inlet bell (11, 20) is provided with a conical inlet part (12, 21), tapering towards the impeller (15, 24), and a mouthpiece (13, 22) connected to the inlet part, and in that a circular flow guide (16, 23) is arranged at the intersection between the inlet part and the mouthpiece of the inlet bell.

Abstract: A vane suspension for angle adjustable mounting of a vane (6) in a hub (1), comprising a seat (3) in the hub and a mounting part on the vane (6). The mounting part on the vane comprises a stud (16) and a shoulder (17) provided at the end of the stud with a partly spherical contact surface (19) facing the blade (15) of the vane, and in that the seat (3) of the hub has a hub shoulder (10) with a partly cylindrical contact surface (12) radially facing the center of the hub (2), which two surfaces are arranged to cooperate mutually by linear contact, whereby the position of the line (21, 21') is constant irrespective of the angular position of the vane in relation to the hub.

Abstract: A valve arrangement includes a valve housing having a circular cylindrical portion in which is formed a valve chamber, a control valve and a valve member. The valve chamber has an inlet adapted to be connected to a pressure-medium source for allowing pressure-medium to flow into the valve chamber and an outlet through which pressure-medium flows out of the valve chamber. The control valve is movable between a closed position in which the outlet of the valve chamber is closed and an open position in which the outlet of the valve chamber is open. The valve member is freely displaceable within the circular cylindrical portion of the valve housing based on the pressure within the valve chamber. The valve member includes a piston which is movable between a closing position in which the piston is adapted to prevent the flow of pressure-medium and an opening position in which the piston is adapted to permit the flow of pressure-medium.

Abstract: The present invention relates to a method for controlling, in an electrostatic precipitator unit comprising discharge electrodes and collecting electrodes between which a varying high voltage is maintained, a pulsating direct current supplied to these electrodes. In the method according to the invention the frequency, pulse charge and/or pulse duration of the pulsating direct current are caused to vary such that a plurality of combinations of frequency, charge and duration are obtained. For each of these combinations, the voltage U between discharge electrodes and collecting electrodes is measured, and for each of these combinations, a voltage level U.sub.ref is determined, measured or calculated. In a defined time interval, for each of these combinations, either the integral I.sub.k =.intg.U.multidot.(U-U.sub.ref).dt is measured and/or calculated during the time interval, or A.sub.i =U.multidot.(U-U.sub.ref) is measured at a number of points of time, whereupon I.sub.k or linear combinations of A.sub.

Abstract: In a method for cleaning polluted gas and/or cooling of hot gas, and a device for carrying out the method, the gas is contacted with finely divided liquid. The finely divided liquid is supplied in the form of essentially umbrella-shaped shells or essentially linear curtains, in a regular arrangement, distributed in two or more planes substantially perpendicular to the main flow direction of the gas. The finely divided liquid is supplied such that the gas is alternatively concentrated and spread by the impulse action exerted by the liquid on the gas in directions perpendicular to the main flow direction of the gas. The orthogonal distance between adjacent planes in which finely divided liquid is supplied, is so adjusted that no substantial equalization of the gas flow takes place between the planes.

Abstract: An air conditioning system for a paint spray booth is located entirely within the booth below the paint application zone for supplying a modified temperature, humidity, and/or filtrated air to the application zone.

Abstract: A method and apparatus for determining the total flow rate of air flowing through a ventilation installation with a free suction fan (15) is described. The flow rate or a corresponding pressure is determined by measurement of the partial flow rate or a corresponding pressure at at least one measurement point in the vicinity of the inlet opening of the fan. A measurement tube (20) open at both ends is suitably used, and oriented with its longitudinal axis in the inflow direction, flow sensors being arranged inside the measurement tube. In this way, there is obtained good measurement accuracy within a large flow range.

Abstract: In a method of cleaning fan impellers bursts of solid material are discharged towards the impeller blades or other parts of the impeller, subjected to deposits, by pulses of compressed air, shot from a compressed air cannon. A device for cleaning fan impellers includes at least one compressed air cannon for directing shots in the form of pulses of compressed air towards the impeller blades or other parts of the impeller. The outlet cylinder (280) of the cannon is loaded with a charge of solid material (4) to be discharged towards the impeller blades or said other parts of the impeller, upon shooting a pulse of compressed air.

Abstract: In a method for cooling a rotary kiln having a cylindrical outer jacket, cooling air is blown at high speed radially towards the jacket from an annular supply-air chamber surrounding the jacket and having a perforated inner wall which is located at a slight distance from the jacket and through which the cooling air is blown towards the jacket. The cooling air is sucked out from the space between the jacket and the inner wall to an annular exhaust-air chamber which is separate from and surrounds the supply-air chamber and communicates with said space. The cooling-air flow through the chambers is adjusted by fan devices connected thereto. A device for implementing this method has an annular supply-air chamber surrounding the jacket and having a perforated inner wall which is located at a slight distance from the jacket and designed for radially blowing cooling air towards the jacket.

Abstract: A device for measuring a gas flow (F) has a measuring body (1) in the form of a cylinder, and a heating device (12) for heating the measuring body. A slot (5) extends axially into the cylinder from one end thereof so as to divide a first portion of the cylinder into two symmetrical halves (6a, 6b). The heating device (12) is disposed in a second cylinder portion which is not divided by the slot (5). A temperature sensor (13) is arranged in the second cylinder portion, and a temperature sensor (14, 15) is arranged in each cylinder half (6a, 6b). For measuring a gas flow (F), the measuring body (1) is so disposed in the gas flow that the slot (5) extends at right angles to the gas flow with one half (6a) facing the gas flow and with the other half (6b) facing away from the gas flow. The measuring body (1) is heated by the heating device (12) to a temperature exceeding the ambient temperature by a predetermined value.

Abstract: In a method for drying a particulate material, the material is supplied into a first drying conduit where it is dried and transported to a first cyclone by means of drying air. The material is separated from the drying air in the first cyclone. The separated material is supplied into a second drying conduit where it is dried and transported to a second cyclone by means of drying air. The material is separated from the drying air in the second cyclone. The drying air is discharged from the respective cyclone. The major part of the drying air discharged from the first cyclone is conveyed to a condenser so as to be subsequently supplied into a first drying conduit, while the remainder thereof is discharged. An amount of the drying air discharged from the second cyclone, which corresponds to this remainder, is conveyed to the condenser to be supplied into the first drying conduit. The remainder of the drying air discharged from the second cyclone is supplied into the second drying conduit.

Abstract: An arrangement for affecting the motions of gasborne, especially air-borne, particles at a movable device, (5,6) comprises an enclosure (12, 22) which encloses said device (5,6) and is connected to a means (16, 28) for supplying or discharging a gas, such as air, to and, respectively, from said enclosure in such an amount that a positive pressure or a negative pressure is maintained therein. Moreover, the enclosure (12, 22) is made of a flexible, gas-permeable material which provides a substantially laminar gas flow downstream of the enclosure and which does not generate particles.

Abstract: A device for mounting vertical bag-shaped filter elements (15) in a filtering chamber in a filtering installation for cleaning contaminated gases which are conducted into the filtering chamber to be filtered by the bag-shaped filter elements and conducted, via the bag openings, to a chamber for clean gas which is located above and separate from the filtering chamber and from which the gases are discharged from the filtering installation, comprises a horizontal, lower tubular element (1) and a horizontal, upper tubular element (4) which extends along the lower tubular element (1) to which it is connected. The lower tubular element (1) forms a clean-gas chamber and has a series of first through holes (10) in its lower tube-wall portion (2b). The bag-shaped filter elements (15) can be mounted on the lower tubular element (1) with the bag openings opposite to the first holes (10).

Abstract: A guide vane for an axial fan is formed in the end portion facing towards the fan with a web between the radially outer and inner portions of the guide vane. The arc length L.sub.2 along the single-curved vane is shorter at the level of the web than at the outer and inner portions L.sub.3 and L.sub.1, respectively.

Abstract: An assembly or coupling arrangement for an impeller associated with a drive shaft. The impeller is supported by the drive shaft by a radial bearing having a small radial clearance. The bearing allows relative rotary motion between the impeller and shaft. In addition, an elastic or resilient element is mounted between the shaft and the impeller to transmit the torque from the shaft to the impeller while preventing or reducing transmission of torque pulsations.

Abstract: A funnel-shaped arrangement (1) for drying and/or cooling vehicles or parts thereof. The funnel-shaped arrangement (1) is longitudinally divided into a number of sections each of which is provided with a plurality, preferably 60-250, of nozzles (7,20,21,22,23,24,25) which are substantially evenly distributed over the curved inner surface of the section and through which the gases are supplied and blown against the vehicle or the parts thereof passing through the arrangement (1), the pressure drop of the gases is measured across the nozzles (7,20,21,22,23,24,25) and the temperature of the gases before the nozzles (7,20,21,22,23,24,25). The measured pressure drop values are then compared with predetermined desired values corresponding to the prevailing temperature, whereupon a pressure increase or a pressure reduction signal is supplied to a first pressure changing means (29) for suplying the gases to the arrangement (1), depending on whether the measured values are below or above the desired values.

Abstract: A method and an installation for recovering energy in the thermal destruction of pollutants in a gas emitted from a scrap preheating device (6,8), e.g. in an electro-steel furnace (1). The polluted gas is conducted through regenerative heat exchangers (12,15) before or after passing through a combustion chamber (4), for providing heat exchange between the polluted cold gas and the cleaned hot gas. The regenerative heat exchangers (12,15) are filled with a packing of a material suitable to be charged into the furnace (1) generating the gases which are used in the scrap preheating process, or into another nearby furnace. The packing is withdrawn completely or partly when the performance of a heat exchanger has deteriorated as a result of oxidation or clogging with dust. A new packing is supplied to the heat exchanger concerned, and the packing withdrawn is charged into one of said furnaces.