Abstract: A heat exchanger having a housing with one or more tubes therein for the transportation of a first fluid through the tubes and a second fluid through the housing and at least partially around the tube or tubes, in which each tube includes two concentric walls with a thin layer or thin layers of a relatively soft material between them applied to the outer surface of the inner wall and to the inner surface of the outer wall.

Abstract: A system for improving the pulse-echo type of testing to determine certain parameters of tubes, such as internal diameter, external diameter, wall thickness, etc. A pair of pulses are directed transversely to the tube wall so that the transit times of the respective pulses and their reflections from a tube surface, are substantially different. From the value of the transit times associated with each pulse pair the respective parameter is derived. Inaccuracies due to undesired oscillations of the driving shaft for rotating the pulse transducer within the tube to be tested are eliminated. By means of auxiliary reflective surfaces each pair of pulses emitted from the transducer are directed transversely relative to the respective tube wall in substantially one and the same plane.

Abstract: A nuclear reactor installation comprising a housing including therein a reactor core and provided with means for dissipating the heat generated in the reactor core during operation, which means comprise a primary cooling fluid circuit passing at least one partly through the reactor core in which is included a pump, a secondary cooling fluid circuit arranged outside the housing of the nuclear reactor and consisting of at least one closed loop in which is included a pump, a loop of the primary circuit being coupled by means of a heat exchanger, to a loop of the secondary circuit, said installation is also provided with means for dissipating the decay heat produced in the core of the nuclear reactor after the reactor has been switched off, which dissipation means are at least partly formed by the primary cooling fluid circuit.

Abstract: The wall thickness of an object is measured on the basis of three consecutive rear wall reflections caused by an ultrasonic wave impinging on the front wall of the object. The time intervals between, on the one hand, the first and second rear wall reflections and, on the other hand, the second and third rear wall reflections are compared. In the event of correspondence of these time intervals, a "good" signal indicative of a true thickness value is produced. The system is adapted for a highly accurate wall thickness measurement, with the feasibility of providing an indication of the percentage of "good" measurements in sequence thereof.

Abstract: A nuclear reactor installation comprising a housing including therein a reactor core and provided with means for dissipating the heat generated in the reactor core during operation, which means comprise a primary cooling fluid circuit passing at least one partly through the reactor core in which is included a pump, a secondary cooling fluid circuit arranged outside the housing of the nuclear reactor and consisting of at least one closed loop in which is included a pump, a loop of the primary circuit being coupled by means of a heat exchanger to a loop of the secondary circuit, said installation is also provided with means for dissipating the decay heat produced in the core of the nuclear reactor after the reactor has been switched off, which dissipation means are at least partly formed by the primary cooling fluid circuit.

Abstract: A sealing bushing for a member rotatable about a vertical axis and extending through a wall of a housing, which bushing comprises a sleeve fixedly connected to the wall of the housing and a sleeve fixedly connected to the shaft of the rotatable member. The last-named sleeve is concentrically received in the first-named sleeve. The bushing further comprises means for maintaining a sealing liquid in the clearance between the sleeves, which clearance opens at its top into a space in which a movable member is mounted that, when urged upwards by the sealing liquid, seals a clearance between the sleeve connected to the shaft and the housing.

Abstract: A sealing bushing for a member including a shaft rotatable about an axis and extending through a wall of a housing, which bushing comprises a sleeve fixedly connected to the wall of the housing and a sleeve fixedly connected to the shaft of the rotatable member. The last-named sleeve is concentrically received in the first-named sleeve to define a small clearance therebetween. The sleeve connected to the shaft is fixedly secured thereto by means of a sealing member of rubber or a similar material.

Abstract: A non-return valve which upon reversal of the flow direction is rapidly closed without impingement of the valve member on the seat with a bang comprises a stationary valve guide bush wherein the valve member is adapted for axial displacement and whereby between the valve guide bush and the valve member there is provided a slotted space such that the closing movement of the valve member is damped just before it impinges on the seat.

Abstract: A heat exchanger comprising a casing wherein a bank of tubes is arranged and provided with means for conducting a first medium through the tubes of the bank from a supply opening for said medium in the wall of the casing, and means for conducting a second medium from another supply opening in the wall of the casing around the tubes of the bank towards a discharge opening in the wall of the casing, whereby the means for conducting the second medium through the apparatus comprise a pump impeller arranged centrally at the bottom of the casing, said impeller being connected to a pump shaft projecting upwardly within a cylindrical inner jacket disposed centrally in the casing and which is driven above the casing by a motor arranged in situ, while the tube bank for the first medium is an annular bank which is arranged around the cylindrical jacket, whereby the tubes of the bank are tubes of the bayonet type.

Abstract: A method of repairing a heat exchanger comprising a housing within which a plurality of spaced apart tubes extend. The method comprises the steps of, once a leak in one of the tubes has been detected, sealing the defective tube at both ends, cutting the defective tube adjacent the ends, removing the tube and mounting a body of suitable shape in its place, thereby ensuring that a proper temperature distribution occurs in the vicinity of the body during operation of the heat exchanger.

Abstract: A method of sealing tube plate apertures, e.g. in heat exchangers, and a repair set for use therein. It is known to seal a tube plate aperture by mounting a capped tube member therein. A disadvantage of the prior method is that the sealed aperture contains a fluid with a temperature different from that of the fluid in the non-sealed tube plate apertures, which results in stresses being generated in the tube plate and an increased danger of leakage. According to the invention this disadvantage is overcome by sealing the aperture in such a manner as to form an insulating space over the major part of the thickness of the tube plate.

Abstract: A method of assembling the parts of a heat exchanger, in which a pipe bundle is lowered into an open-topped vessel, and a wall of the bundle is secured to the wall of the vessel by welding. Prior to placing the bundle in position, a sealing ring is provided around the bundle between the outer periphery of a circumferential wall thereof and the inner periphery of the wall of the vessel, which ring hermetically seals the annular opening between the pipe bundle and the wall of the vessel after the bundle has been placed in position. The sealing ring is desirably made of a deformable material having suitable dimensions to be compressed axially between an outwardly extending wall portion of the pipe bundle and an inwardly extending wall portion of the vessel when the pipe bundle is fully lowered into the vessel. The seal ring may be made of material which melts at the operating temperature of the heat exchanger and can be thereby eliminated after welded joint has been tested satisfactorily.

Abstract: A heat shield, for example, for a pump for liquid sodium, formed so that the space between the shield and a wall can be optimally sealed during operation. The heat shield thus retains more radiant heat and prevents a disturbance of a rotation-symmetrical thermal condition. To achieve the object, the heat shield, in one form, consists of two layers of materials having different coefficients of expansion, and in an alternative form, of two parts the spacing between which can be adjusted by mechanical means in a pivoting manner.

Abstract: The invention provides a fluid diode comprising a chamber between a supply pipe and a discharge pipe, in which chamber there are present balls within a space defined by two grids. The grids and balls are such that the grid at the side of the supply pipe with certainty can be shut off almost completely when a reverse flow occurs, whereas the other grid never can be shut off by the balls. A preferred embodiment is given in FIG. 1. The grid at the side of the discharge pipe may also be a perforated plate provided with bulges of different heights.

Abstract: The present invention relates to a tube sheet comprising two parallel interspaced sheet members which are provided with aligned bores through which at least partly with interposition of sleeves, extend tubes or tube sections. The sleeves are provided with internal chambers which through openings in the sleeve wall communicate with the space between the sheet members. The tube plate according to the present invention is highly resistant to thermal shocks in that the internal chambers in the sleeves extend to beyond at least one of the sheet members, in particular the thermally heaviest loaded part.

Abstract: A method of temporarily sealing off the open ends of a plurality of fluid transport conduits that terminate in a common header space. A sealant material in the liquid state, preferably enclosed in a flexible envelope of non-permeable resilient material, is introduced through an access opening into the header space of, for example, a multi-tube heat exchanger. Sufficient sealant material is introduced to at least partially fill the header so as to close off the openings to the desired number of fluid transport conduits (e.g., heat exchanger tubes). The sealant is subsequently converted to the solid state, thereby providing simultaneously a firm, vacuum-tight seal for the end of each conduit to permit, for example, the identification of a leaking tube by conventional vacuum testing techniques. Following completion of such test procedures, the sealant material can be removed from the header by first reliquefying it, and then draining the sealant material from the header.

Abstract: An X-ray tube having a cathode serving as a source of electron rays and a rotatable anode, with which for example a tube-to-tube weld connection can be tested throughout without changing the position of the tube. For that purpose the anode of the tube is bevelled so that a rotating X-ray beam can be obtained by rotating the anode.

Abstract: A method for sealing leaking pipes in heat exchangers, comprising the installation, after detection of a leak and determination of the leaking pipe, of extension pieces on the two ends of the pipe, the severing of the pipe adjacent one end and the cutting of openings in the pipe wall adjacent the other end. Subsequently flow conductor tubes are inserted in the two ends of the pipe, and sealing caps are installed on the extension pieces. In operation the pipe is now entirely traversed by the liquid that normally flows around the non-defective pipes. The creation of so-called dead spaces (i.e., stagnant regions) is thus avoided.