Abstract: A flange connection for pipes has a plug connection member having a pipe section and a flange connected to one end of the pipe section, wherein the pipe section has a mounting seat and a sealing seat. The plug connection member also has a first sealing ring seated in an initial position in the mounting seat, wherein the first sealing ring rolls from the mounting seat into the sealing seat and into a sealing position when the pipe section is inserted into a pipe end.

Abstract: A louver type shutter for ventilation systems has hollow flaps which are pivotally mounted in a frame. Seals made from a foamed sheet material are located between the flaps and the frame and the front edges of the flaps are pressed directly into the foam sheet.

Abstract: The flexible corrugated tube is made of spirally coiled thin metal strip with corrugations extending parallel to the longitudinal direction thereof, in which tube at least one corrugation of the one side edge of the one convolution (2) lies respectively in at least one corrugation on the other overlapping side edge of the subsequent convolution (3) and the crests of corrugations lying in each other are pressed down by only a part of the corrugation height in such a manner that the corrugation crests are wider than the corrugation cross-section beneath same.

Abstract: A fluid flow regulator wherein a shaft which extends transversely of the passage in a tubular housing carries a flap having two mutually inclined sections. A spring biases the flap to a fully open position and the flap is moved from such open position toward a fully closed position by the fluid which flows through the passage in a direction from the one toward the other axial end of the housing. A flow restricting device is installed in the housing so that it defines one or more channels for the flow of fluid against one or more selected portions of or against the entire flap, depending upon whether the flap extends across the entire passage or across a central portion of the passage. The flow restricting device enhances the sensitivity of the flap so that the latter can change its position in response to each variation of the pressure of fluid which is caused to flow through the housing at a relatively low pressure.

Abstract: An arrangement for regulating the flow of a gaseous medium in a conduit includes a flap valve pivotably mounted in the conduit and biased by a spring toward its open position and by the pressure of the gaseous medium flowing through the conduit towards its closing position. A rod-shaped member is pivotally mounted on one section of the flap valve, and a sleeve-shaped member is pivotally mounted on a plate-shaped element rigid with the conduit and extending axially thereof downstream of the flap valve. The sleeve-shaped member has a passage therein in which the rod-shaped member is received with play so that, upon rapid movement of the rod-shaped member in the passage, the sleeve-shaped member is entrained by friction on pivots, thus seizing the rod-shaped member. In this manner, the flap valve is prevented from fluttering, while its responsiveness to gradual pressure changes of the gaseous medium is unaffected.

Abstract: A flexible corrugated tube comprising a succession of convolutions of spirally coiled thin metal strip having the overlapping corrugations of adjacent convolutions locked together by a plurality of spaced apart detents about the circumference of at least one of the sets of overlapping corrugations. Apparatus for forming the tube comprises a grooved roller in which at least one of the grooves comprises ridges extending a limited distance from the groove base toward the roller surface.

Abstract: The shaft for the flap of a fluid flow regulator extends through the tubular housing of the regulator and its end portions are received in thrust bearings which subject the shaft to axial stresses. The bearings have internally threaded sleeves which are bonded to the housing, externally threaded plastic plugs which mate with the respective sleeves and have sockets for the respective end portions of the shaft, and hard metallic balls in the innermost portions of the respective sockets. The flap has two mutually inclined sections at the opposite sides of the shaft and is biased to open position, in which one of its sections lies flush against a centrally located partition in the housing, by a helical spring whose characteristic can be changed from the outside of the housing.

Abstract: This invention relates to apparatus for manufacturing tubes by the helical coiling of a strip into successive convolutions. The strip is preferably of a corrugated sheet metal. The coiling means of the apparatus comprises a plurality of non-driven freely rotatable and radially adjustable guide rollers adapted to guide and support the strip during the formation of a convolution. These rollers are arranged on a circle so that they engage the convolution at its outside. Arranged at the point of the strip entry into the coiling means is an inner and an outer connecting roller, the inner connecting roller positioned within and the outer connecting roller positioned outside the circle on which the guide rollers are situated. The connecting rollers have the purpose of joining a convolution after its travel past the guide rollers to the incoming strip so that convolution and strip overlap each other.

Abstract: A flow regulator for air ducting comprises a flap which can be rotated about a shaft against the action of a spring, by the air current, to regulate air flow therepast. The flap has two portions which are disposed at an obtuse angle to each other about a bend line, one of the portions, in an open condition of the regulator, being directed downstream of the shaft generally parallel to the ducting axis, and is obliquely oriented in the closed condition and the other portion, in a closed condition of the regulator, is disposed in a plane lying at right angles to the ducting axis, and is obliquely oriented in the open condition. The obtuse angle of the flap portions is preferably of the order of 145.degree. to 155.degree..

Abstract: The specification describes a flow regulator for ducts in the case of which the free cross-section of the duct is arranged to be varied by a flap which can be turned against spring force by the flow in the closing direction. The flap is angled adjacent to the shaft and its one limb in the open position is directed substantially parallel to the axis of the duct to the rear and its other limb is directed in the closed position substantially perpendicularly to the duct axis. The spring force is adapted to act from the direction of the wall of the duct on a lever arm attached to the shaft in such a manner that the point of action of the force on rotation of the flap out of the open position into the closed position describes a circular arc, which are at the beginning is more oblique to the direction of the spring force than at the end.