Abstract: A screw compressor of the kind incorporating at least one male rotor and one female rotor, with helically extending lands and grooves. The female rotor (1) is injection moulded from a plastics material having a modulus of elasticity of at most 25,000 N/mm.sup.2. The lands (3) of the female rotor have a thickness (a) which is so adapted to the modulus of elasticity of the plastics material as to allow the lands to be deflected resiliently when clashing with the other rotor (2), as a result of dimensional deviations of the order likely to occur during hardening or curing of the plastics material, or at prevailing temperature variations, but not as a result of the pressure exerted by the working fluid. Due to the injection moulding the surface smoothness is fine enough to make subsequent finishing unnecessary and damages caused by lack of machining are avoided because of the resilient deflecting of the lands of the female rotor when clashing with the other rotor.

Abstract: Apparatus for catalytic cleaning of the exhaust gases of furnace systems. For selectively eliminating nitrogen oxides in the exhaust gases of furnace systems, chemical compounds, such as ammonia in vapor form, are introduced into the exhaust gases emerging from the furnace systems. The exhaust gases are then passed through a catalytic converter, which initiates and/or accelerates the reaction of the oxides of nitrogen with the admixed chemical compounds. In different zones in the catalytic converter, the exhaust gases that are to be treated catalytically and of at least one current of cleaning gas are passed in a countercurrent. The location of the catalyst zones through which the exhaust gases and the cleaning gas, respectively, flow is varied continuously or intermittently. The catalytic converter has catalyst elements disposed in a carrier, and the carrier and the gas connections relative to one another.

Abstract: Apparatus for cleaning the heat-exchanging surfaces of the storage elements of rotary regenerative heat exchangers. The apparatus has a row of nozzles oriented substantially at a tangent and in a radially displaceable manner before the end face of the storage element (1) in the interior of the heat exchanger, which cause the cleaning material, delivered to them from a source of cleaning material, to emerge in an aimed manner onto the storage element (1). The nozzles are provided on at least two spaced-apart nozzle heads (19; 17) disposed a tube (11; 13) extending substantially radially over one half of the end face of the storage element (1), the tube being guided into the interior of the heat exchanger in a sealed manner and being movable by a drive means radially back and forth above the storage element (1). Via movable connecting means, the tube (11; 13) is connected to at least one external, stationary material line delivering the cleaning material.

Abstract: Method and apparatus for reheating of cleaned gases subsequent to wet cleaning of raw gases.Cooled cleaned gases of high humidity which have been subjected to a wet cleaning process are reheated by means of regenerative heat exchange with as yet uncleaned, hotter raw gases, a previously already heated partial flow of cleaned gas being added to the cleaned gas flow prior to the performance of the regenerative heat exchanger. The partial flow of cleaned gas is diverted from the previously wet-cleaned total flow of cleaned gas, prior to the regenerative reheating of the cleaned gases by means of heat energy withdrawn from the raw gases, is increased in pressure, and is heated, separately from the main flow of the cleaned gases, in a regenerative heat exchange with the raw gases.

Abstract: A screw compressor having two rotors (2,3) rotatably journalled for mutual meshing engagement in a respective working chamber (4,5) of a compressor housing (1). For the purpose of regulating the pressure ratio and the capacity of the compressor, a composite slide assembly comprising two slides (17,18) is mounted for axial movement in a recess (6) in the housing (1), the composite slide having two flanks which form a continuous wall in the two working chambers (4,5). The two slides are individually movable and, for the purpose of improving the regulating function one of the slides (18) is provided with a flank which forms a wall of the working chamber (4) of solely one rotor, preferably the male rotor (2).

Abstract: An ejector pump has a ringshaped nozzle slot directed radially outwards followed by a radially directed mixing zone interacting with a secondary channel and a radially directed diffuser slot.To achieve an improved performance, and especially one having a characteristic less dependent to decreases of working medium pressure the ejector pump is comprised of two mutually fixed blocks (1, 2) having each an end surface (4, 6). Said end surfaces (4, 6) are facing each other forming an annular slot (12). The surfaces of the nozzle slot and the diffuser slot are profiled in at least one of said end surfaces (6) separated by an annular groove (7) in said end surface, which groove (7) communicates with the secondary channel. The diffuser slot height adjacent the groove (7) is larger than the nozzle slot height (h.sub.o) adjacent said groove decreasing outwardly by the way of at least two bevels, first one having an angle of bevel .alpha..sub.1 =8.degree.-15.degree. and then one having an angle of bevel=4.degree.-8.

Abstract: A control device for regulating the capacity and the built-in volume ratio of a helical screw rotor machine comprises at least one additional valve member which is axially aligned with first and second valve members in the screw rotor machine, the additional valve member being movable between the positions in which said additional valve member contacts one or both of said first and second valve members to form an extension of either or both of the first and second valve members. The additional, first and the second valve members are connected to the operating device to permit displacement thereof. This permits varying the length of the second valve member (the slide valve) in one or more steps, which in turn means that it is possible to displace the gap between the first and second valve members without moving the high pressure end of the second valve member (the slide valve).

Abstract: A pack of heat transfer plates for regenerative heat exchangers comprising superimposed profiled plates. Each plate is provided with spaced parallel double ridges protruding symmetrically from both sides of the plate and extending obliquely relatively to the general direction of the fluid flow through the pack. The plates are disposed such that the ridges of one plate lie transverse to the ridges of adjacent plates so that the plates are in contact with each other solely at points spaced along the crests of the ridges.

Abstract: Screw rotor compressor comprising intermeshing male and female rotors. The leading flank of each male rotor groove comprises a portion intersecting with the pitch circle and following a circular arc having its center inside the pitch circle. In the point of intersection the tangent to the arc forms an angle of 0.25 rad to 0.75 rad with a radius of the rotor, and the radius of the arc forms an acute angle with a line connecting the center of the arc with the center of the rotor.

Abstract: A rotary regenerative heat exchanger comprises a plurality of moving sector-like rotor compartments carrying regenerative heat exchange material, in which leakage of a gaseous medium having a lower pressure and being trapped by a stationary section plate in the sector-like compartments to a gaseous medium of a higher pressure is at least reduced by the provision of a means for adjusting the sector plate to such an axial clearance with respect to the end of the rotor that an intentional amount of direct leakage of the high pressure medium is maintained between the rotor end and the sector plate, giving rise to forcing out the low pressure medium from compartments that are about to leave the low pressure medium passage and replacing it with high pressure medium.

Abstract: A rotary regenerative heat exchanger comprising an inner cylindrical post shell, an outer cylindrical shell interconnected with said inner shell by a radial partition wall, and rigid sealing rings at opposite ends of the outer shell. The outer or the inner end portion of each radial partition wall is slidingly adopted in an axial slot in the outer or inner shell, respectively, and the outer end portions of each partition wall are also slidingly engaging said sealing ring in a radial direction in order to isolate the floating sealing rings from the thermal deformation of the load carrying structure.

Abstract: Apparatus and method for cleaning the heat exchanging surfaces of the heat transfer plates of rotary regenerative heat exchangers comprising low to medium pressure gas and/or steam operated nozzles of the injection type having injection tubes for moving by suction ambient heat exchanging gas or air into the interspaces between the heat transfer plates. The nozzles may be designed as supersonic nozzles, especially Laval nozzles.

Abstract: A gas compression system and method utilizing an oil-injected rotary compressor, an oil separator in the discharge line thereof, and an oil supply line between the oil separator and the working space of the compressor. Said oil line conducts oil and gas dissolved in the oil to a throttling device incorporated in the line which causes a decrease in the temperature of the oil due to boiling off of the gas dissolved in the oil, which cooled oil is then conducted into the working space of the compressor. The invention applies to refrigeration systems.

Abstract: A fire detection apparatus in a rotary regenerative air preheater comprises a plurality of temperature sensitive detectors which produce an electrical signal, and means for differentiating the electrical signals from the detectors. The differentiated signals are passed through a low pass filter having a large time constant and are then fed to a comparator which actuates a signalling device when the low pass filter output signal exceeds a predetermined value.

Abstract: A refrigerating system comprises a liquid refrigerant supply line connecting the outlet of a condensor with a throttle valve connected to the inlet of an evaporator, a first liquid refrigerant receiver tank intermittently disconnected from the supply line and connected to a special suction line for performing a liquid refrigerant precooling sequence by drawing vapor from the receiver tank during time periods when the refrigerating cycle is continuously maintained via an additional receiver tank connected between the condensor and the throttle valve.

Abstract: Two stage screw compressor having two working spaces provided side by side with parallel axes within a common barrel member and extending in the same direction from a common plane surface of an end plate member in which one rotor of each stage are interconnected by a gear transmission including an input power shaft.

Abstract: Volume control valve for a screw compressor located in a cylindrical bore parallel to and spaced from the working space. The bore and the working space communicate through a number of axially distributed channels which are selectively closed by an adjustable valve member disposed in the bore.

Abstract: Apparatus for cleaning the heat exchanging surfaces of the heat transfer plates of rotary regenerative heat exchangers by using a row of high pressure directional jets of cleaning fluid directed into the interspaces between the plates and hitting deposits positioned in the interspaces essentially in the shape of a moving row of impact points.

Abstract: A refrigeration plant including an oil-injected compressor, an oil separator, a condenser and an evaporator. The plant comprises means to introduce liquid refrigerant to the compression phase of the cycle ahead of the oil separator. The plant further comprises means to adjust the amount of liquid refrigerant introduced in response to the temperature difference between the condenser and the oil separator, in order to keep the difference on a constant level of 5.degree. C. to 15.degree. C.

Abstract: Screw rotor compressor comprising intermeshing male and female rotors. The leading flank of each male rotor groove comprises a portion intersecting with the pitch circle and following a circular arc having its center inside the pitch circle. In the point of intersection, the tangent to the arc forms an angle of 0.25 rad to 0.75 rad with a radius of the rotor, and the radius of the arc forms an acute angle with a line connecting the center of the arc with the center of the rotor.