Abstract: The heat exchanger tube comprises a cylindrical, smooth walled outer tube (1) of steel into which a profiled insert (2) of aluminium is inserted. The profiled insert is constituted by two half shells (3,4) which engage in one another at their longitudinal edges with groove-shaped recesses (7) and rib-like projections (8). Both half shells (3,4) carry longitudinally extending ribs (5) on their internal surface which are so aligned that each half shell with its ribs constitutes a profile which is open on one side.

Abstract: A weatherproofing door for an air inlet opening of a ventilating unit. The door has an upper and a lower horizontal doorframe section that can be pivoted outwardly, about vertical axes, in the housing frame that surrounds the air intake opening. Vertically extending, lamellar profiled drop-extracting members that are disposed next to one another extend between the two horizontal doorframe sections. Between the outer and inner sides of the door, the profiled members have profile curvatures that are laterally directed in the same direction, with the height of the profile curvatures, in a horizontal direction, being at least as great as the horizontal clear distance of the air passages between the profiled members. The lower horizontal doorframe section has a drain that communicates with the air passages.

Abstract: A furnace for burning oil or gas. The furnace has a vertical, cylindrical water jacket, with a combustion chamber being disposed at the upper end of the furnace, and a flue gas collector being disposed at the bottom end of the furnace. At least one ancillary heating tube leads downwardly in the water jacket from the combustion chamber to the flue gas collector. At least the bottom half of the ancillary heating tubes are provided with a corrosion-resistant inner side. Cup-shaped guide elements are disposed one above the other within the heating tubes. The upper rim of each of the guide elements rests against the wall of the heating tube, and the recessed cup portion of each of the guide elements is spaced from the wall of the heating tube. This recessed cup portion has radially oriented holes for directing a plurality of flue gas streams radially against the wall of the heating tube. Below the opening of the heating tube, the flue gas collector is provided with a chamber for collecting condensate.

Abstract: A heat exchanger comprising a rectangular exchanger pack which consists of a plurality of individual, mutually spaced, foil-type plates which have triangular corner notches and are connected with one another in sealed manner on marginal strips which extend between the corner notches in pairs on two opposite plate margins for the formation of alternately crossing flow-through passages between the plates, and comprising a frame housing surrounding the exchanger pack comprising two covers disposed adjacent the outer plates of the exchanger pack and four struts connecting the covers at their corners. The marginal strips to be connected of each two adjacent plates of the exchanger pack rest flatly upon each other and are mechanically connected with each other by folding over at least once. The struts of the frame housing define a triangular recess on their side facing the edge of the exchanger pack. The pack edges with the corner notches project into these recesses.

Abstract: A boiler provided with a burner chamber for a burner firing system and a combustion chamber for a solid fuel firing system, both chambers being arranged horizontally side by side in a common boiler water space enclosed by a horizontal outer boiler body. The combustion chamber has an approximately elliptical cross-section with vertical major diameter and the burner chamber has a round cross-section, the longitudinal center lines of both chambers being substantially at the same level. Both chambers are connected at their front ends with two separate horizontal ancillary heating passages extending axially parallel above the chambers within the boiler water space and having rectangular cross-sections with horizontal major cross-sectional dimensions and with internal comb-like ribbings. The outer boiler body is made of a metal sheet shaped in one piece by rolling into a hollow body of non-circular roundish cross-section.

Abstract: A deposit filtering apparatus and method for filtering turbid liquids. The apparatus is provided with an essentially cylindrical, vertical filter container, in which sieve-like plate-shaped filter elements are arranged vertically between the turbid liquid chamber and a filtrate chamber of the filter container. That side of the filter element facing the turbid liquid chamber is covered with a detachable filter membrane formed by depositing thereon a suspension agent aiding the filtering process. The turbid liquid chamber is connected to a turbid liquid conduit for supplying the turbid liquid, and the filtrate chamber is connected to a filtrate conduit for discharge of the filtered liquid. The bottom of the filter container has a closeable opening for removal of the filter cake, consisting of filtering aid agent and impurities, separated or detached from the filter elements. A filter element packet, which is closed on the four vertical sides thereof, is arranged as a removable unit in the filter container.