Abstract: An apparatus for the automatic control of ventilation of premises comprising a flexible flat membrane (11) attached by one of its edges in the interior of the casing (12) on the upper wall between two opposed openings (18) and (19). The upper wall supports the membrane. The membrane buckles and bends under the effect of an air current flowing through said casing in order to seal and block one of the openings (18) or (19) to a larger or smaller extent. The bending strength of the flexible planar membrane (11) is made different according to the direction of actuation of the membrane by the presence of the stops (13) and (15) which have a different length on both sides its attachment. This difference can be increased by the presence of perforations and holes in the membrane at the level of the stop closest to the attachments.

Abstract: A ventilator for use on a conduit having an upwardly open mouth has a generally toroidal annular flow body surrounding the conduit immediately below the mouth thereof. This body has an outer wall having an outwardly convex lower portion spaced outwardly from the conduit and an upper portion extending generally asymptotically upward and inwardly from the lower portion to the conduit and joining the conduit substantially at the mouth. Air flow is induced over the body to create a low-pressure zone at the mouth by providing a horizontal deflector disk suspended above the mouth and having an outer periphery extending outwardly beyond the mouth so as to define with this mouth an annular gap having a flow cross section greater than that of the mouth. The disk may be combined with a fan that generates a downwardly flaring air stream that moves downwardly around the periphery of the disk and across the gap.

Abstract: A ventilating assembly is formed of three basic modules, namely a base unit constituted as a static ventilator, a turbine unit constituted as a wind-operated ventilator, and a drive unit which can operate the turbine unit as a motor-driven ventilator. The base unit is affixed to the top of a chimney or a vent stack and can operate all alone as a static ventilator. The turbine can be attached to a seat on this base unit so that the turbine fan lies in a venturi chamber formed between upper and lower portions of the base unit. If desired the motor unit can further be mounted on top of the base unit and the motor output shaft connected to the turbine to drive same.

Abstract: A ring clamp has a pair of flexible sheet-metal strips formed into a ring with one end of each strip juxtaposed with the one end of the other strip, and the other end of each strip lying intermediate the ends of the other strips. The buckles are each formed of a pair of sheet-metal parts one of which has ends bent over and formed with channels into which fit similar channels of another latch part whose ends are in turn bent over the first part for locking-together of the entire buckle into a rigid unit without the use of welding or rivets. Furthermore each buckle has inwardly directed teeth that can bite into the object being clamped. When the ends of the clamp are drawn together to tighten it around an object the two buckles are tightly pressed against the object and prevent sliding of the two strips relative to each other.

Abstract: A lost mold for the casting of the ferrule, nozzle or mouthpiece of a chimney or smokestack consists of a light-weight relatively thin material which can burn off, wear or degrade in use and which is stabilized in a casting chest or box with sand for the casting of the concrete body adapted to form the ferrule or mouthpiece. The lost mold permits the casting of a draw-promoting device for a chimney by masons at the site of erection thereof and hence eliminates the need to transport massive bodies long distances. It also eliminates difficulties encountered with the shaping of the mouth of a smokestack or chimney by masons or chimney specialists.