Abstract: A lined conduit formed by decorrugating a corrugated liner conduit inside a first conduit is described. A method and apparatus for forming the lined conduit are also described. The corrugated liner conduit may be positioned inside the first conduit. Each end portion of the corrugated liner conduit may be coupled to a hydraulic expander. Each hydraulic expander may include a hydraulic cylinder. Each hydraulic cylinder may include a piston rod with an opening along the length of the piston rod. The corrugated liner conduit may be evacuated through a valve assembly coupled to the passageway in one of the piston rods. The evacuated corrugated liner conduit may be pressurized with fluid from a fluid source coupled to the valve assembly. Pressurizing the corrugated liner conduit may expand corrugations in the corrugated liner conduit to form a decorrugated liner in the first conduit.

Abstract: A machine may produce a tube having textured internal and external surfaces in a single operation. Inner and outer knurling tools may form the textured surfaces. The texturing of the internal and external surfaces may be helical patterns of ribs and grooves. The height of the ribs formed in the internal and external surfaces may be less than about 35 mils. The angles of the patterns relative to a longitudinal axis of the tube may be less than about 45°. The angle of the helical pattern allows textured tubes to be used as heat exchanger elements wherein flow is directed substantially coaxial to the longitudinal axes of the tubes. The helical pattern formed in the external surface may be oriented in a right hand or left hand helical orientation. Similarly, the helical pattern formed in the internal surface may be oriented in a right hand or left hand orientation.

Abstract: A conduit modifier may be used to corrugate at least a portion of a conduit. The conduit modifier may include at least a first plurality of rollers arranged in a first pattern around a passageway. The first plurality of rollers may form ridges and grooves lengthwise along a conduit passing through the passageway. A second plurality of rollers arranged in a second pattern around the passageway may compress ridges formed by the first set of rollers. The ridges may be formed such that a distance from a central axis of the conduit to a highest portion of an outer surface of a ridge is substantially equal to a distance from the central axis of the conduit to an outer surface of the un-corrugated portion of the conduit. The corrugated portion of the modified conduit may be expandable.

Abstract: A machine may produce a tube having textured internal and external surfaces in a single operation. Inner and outer knurling tools may form the textured surfaces. The texturing of the internal and external surfaces may be helical patterns of ribs and grooves. The height of the ribs formed in the internal and external surfaces may be less than about 35 mils. The angles of the patterns relative to a longitudinal axis of the tube may be less than about 45°. The angle of the helical pattern allows textured tubes to be used as heat exchanger elements wherein flow is directed substantially coaxial to the longitudinal axes of the tubes. The helical pattern formed in the external surface may be oriented in a right hand or left hand helical orientation. Similarly, the helical pattern formed in the internal surface may be oriented in a right hand or left hand orientation.

Abstract: A machine may produce a tube having textured internal and external surfaces in a single operation. Inner and outer knurling tools may form the textured surfaces. The texturing of the internal and external surfaces may be helical patterns of ribs and grooves. The height of the ribs formed in the internal and external surfaces may be less than about 35 mils. The angles of the patterns relative to a longitudinal axis of the tube may be less than about 45°. The angle of the helical pattern allows textured tubes to be used as heat exchanger elements wherein flow is directed substantially coaxial to the longitudinal axes of the tubes. The helical pattern formed in the external surface may be oriented in a right hand or left hand helical orientation. Similarly, the helical pattern formed in the internal surface may be oriented in a right hand or left hand orientation.

Abstract: A corrugated heat exchanger element may have grooves and ribs on the interior and exterior surfaces of the tube. The corrugations on the tube may be linear corrugations or helical corrugations. The texturing of the interior and exterior surfaces of the tube, and the corrugations in the tube may provide a heat exchanger element that has a large surface area. The surface texturing and corrugations may also provide a heat exchanger element that promotes internal mixing of fluids that flow by and through the element. Increased internal mixing and increased surface area of an element may allow the heat exchanger element to have a high heat transfer coefficient. A heat exchanger element or heat exchanger elements may be assembled into a heat exchanger that has a high overall heat transfer coefficient. Ends of the heat exchanger element may be pointed to facilitate attachment of the element to a support structure.

Abstract: Flexible convoluted conduit covered with braid made by cold forming the braid to an end of the conduit. Cold forming can involve magneforming. Resulting conduit is not brazed, welded, or annealed, thereby facilitating construction of convoluted conduits with higher working pressures and/or less braid material.

Abstract: Flexible convoluted conduit covered with braid made by cold forming the braid to an end of the conduit. Cold forming can involve magneforming. Resulting conduit is not brazed, welded, or annealed, thereby facilitating construction of convoluted conduits with higher working pressures and/or less braid material.

Abstract: Convoluted conduit covered with braid made by cold forming the braid to an end conduit or an end section of the convoluted conduit. Cold forming can involve magneforming. Resulting conduit need not be brazed, welded, or annealed, thereby facilitating construction of convoluted conduits with higher working pressures and/or less braid material.

Abstract: Multi-passage heat exchange element which includes an elongated central first fluid passage for passage of a first fluid of a heat exchanger, a plurality of substantially helically convoluted second fluid passages for a second fluid of a heat exchanger, the second fluid passages substantially helically surrounding at least a portion of the elongated central passage, and a plurality of substantially helically convoluted first fluid passages for passage of the first fluid of a heat exchanger, the first fluid passages substantially surrounding at least a portion of the second fluid passages.

Abstract: Multi-passage heat exchange element which includes an elongated central first fluid passage for passage of a first fluid of a heat exchanger, a plurality of substantially helically convoluted second fluid passages for a second fluid of a heat exchanger, the second fluid passages substantially helically surrounding at least a portion of the elongated central passage, and a plurality of substantially helically convoluted first fluid passages for passage of the first fluid of a heat exchanger, the first fluid passages substantially surrounding at least a portion of the second fluid passages.

Abstract: A method for producing corrugated tubes of substantially high surface area for use in tube-in-shell heat exchangers which are particularly efficient for cooling water involves pointing a heat exchange tube at both ends to reduce the diameter substantially and increase the wall thickness of the pointed ends and then corrugating the tubes linearly. The tubes each having intermediate portions linearly corrugated to provide equally spaced deep corrugations extending in a straight line parallel to the axis of the tubes. The corrugations, which are equivalent to tubes, multiply the amount of heat transfer attainable from the point diameter selected for attachment to the tube sheets. The ratio of the surface area of the corrugated body portion to the surface areas of said reduced ends, per unit length, is in the range from about 1.5:1 to about 4:1. It also makes possible the contiguous relation of each tube to the surrounding tubes.

Abstract: An apparatus for heating a liquid by mixing combustion products therewith comprises a housing having a liquid reservoir compartment, a mixing chamber above the reservoir having a tortuous fluid flow path, a combustion chamber above the mixing chamber with a gas burner and apparatus for igniting and burning a mixture of air and fuel and an apertured water jacket at the upper end. A pump draws liquid from the reservoir and discharges it through the water jacket on the combustion chamber side wall to cool the burning mixture. The discharged liquid collects at the lower end of the combustion chamber and flows evenly throughout the tortuous fluid flow path (Raschig rings) in the mixing chamber to thoroughly mix hot combustion gases with the hot liquid mixture for maximum heat transfer. The mixture falls through an air space into the reservoir to separate the excess gases for venting to atmosphere. The heated liquid may be circulated through a hot water supply piping system for industrial usage.

Abstract: An apparatus for heating a liquid by circulating combustion products comprises a housing having a liquid-containing reservoir compartment and a burner compartment thereabove containing a fuel burner for burning a mixture of air and combustible gases, liquids or particulate solids. An electric motor mounted above the burner has a shaft extending downward into the liquid in the reservoir with an impeller on the lower end submerged in the liquid. Rotation of the impeller produces suction in the liquid drawing hot combustion gases into the liquid and disperses the same as hot gas bubbles which heat the liquid efficiently. A portion of the liquid is conducted from the reservoir and discharged close to the burner to cool the burning mixture. The heated liquid may be reycled through a hot water supply piping system for industrial usage. A coil submerged in the reservoir allows a second liquid to be heated thereby for use in a hot water supply system for residential or industrial usage.

Abstract: A novel metal tube corrugating die comprises a hollow die body with a plurality of die teeth in an internal cavity. The die teeth are flat with a curved edge extending diagonally into the die cavity providing a die corrugating tooth surface extending inward along a curved line. The die teeth are spaced uniformly around the interior of the die body. The die teeth are positioned somewhat on a helical line and are each tilted away from the other so that the planes of the individual teeth intersect substantially on the longitudinal axis of the die at a point foreward of a plane normal to the die body and passing through all of the die teeth. A mathematical equation expresses the optimum clearance between the die teeth. When a thin-walled, hollow tubing is inserted in the die, held against rotation, and the die body rotated relative to the tubing, the die teeth corrugate the tubing.