A heat exchanger comprising helically wound tube bundles is disclosed. The helically wound tube bundles are joined with tube sheets to define a primary working fluid system that is fluidically isolated from a secondary working fluid system. The tube sheets and tubes are formed of the same material, which facilitates their joining by means of joints that are substantially galvanic corrosion-resistant joints.

Helical tube bundle arrangements for heat exchangers

In accordance with the present invention, a method of polishing stone and an article for use in the method are presented in which the stone has at least one exposed surface, the method comprising the steps of: a) bringing into frictional contact an abrasive article to the exposed surface of the stone; and b) refining the exposed surface of the stone with the abrasive article, preferably in the presence of water, wherein the abrasive article comprises a plurality of abrasive particles adhered to a backing (preferably a flexible backing) by a binder (preferably a resilient binder), wherein the binder comprises a cured resin derived from a resin comprising unsaturated addition polymerizable units. The binder and abrasive particles (and plasticizer when used) form a resilient composite having a hardness no greater than 20 HK but at least 1 HK. Use of the articles and method of the invention efficiently increases the gloss of stone surfaces.

Article for polishing stone

A hybrid plate-fin heat exchanger for exchanging heat between a first fluid and a second fluid is disclosed. The hybrid plate-fin heat exchanger comprises a plurality of plates, each of which comprises channels for conveying the first fluid. Fins are brazed onto each plate, wherein the fins define a plurality of flow channels for the second fluid. The plates are joined to one another via friction-stir welding in such a way that the brazed regions are fluidically isolated from the first fluid during operation. As a result, the heat exchanger is suitable for use in applications that use a first fluid, such as seawater or geothermal fluid, which is corrosive for the brazed regions.

Heat exchanger and method for making

The present invention offers an improved axial heat exchanger for exchanging heat between a gas medium and a fluid or liquid medium. The axial heat exchanger comprises a longitudinal and substantially axially extended outer channel that is adapted to enclose a flow of a first gas medium. The heat exchanger also comprises a plurality of substantially parallel inner channels that are adapted to enclose a flow of a second liquid medium. The inner channels are arranged inside the outer channel so as to extend substantially axially along the inside of said outer channel for enabling a transfer of heat between said first gas medium and said second liquid medium. The heat transfer is improved to some extent as the number of inner channels increases and it is further improved in that at least one of the inner channels is joined with at least one elongated sheet. The sheet is arranged to extend substantially axially along the inner channel so as to substantially coincide . with the direction of flow of the first gas medium through the outer channel.

Axial heat exchanger

A heat exchanger comprising a plurality of plates that are demountably attached to a frame is disclosed. Each plate comprises a plurality of channels for conveying a primary fluid through the heat exchanger. The frames are arranged in the frame so that spaces between adjacent frame pairs define conduits for conveying a secondary fluid through the heat exchanger. The plates are mounted in the frame so that they can be individually removed from the frame. Further, each of the channels is fluidically connected to input and output ports for the primary fluid by detachable couplings. As a result, heat exchangers in accordance with the present invention are more easily repaired or refurbished than prior-art heat exchangers.

Modular Heat Exchanger

A heat exchanger for use in nuclear reactors includes a heat exchange tube bundle formed from similar modules each having a hexagonal shroud containing a large number of thermally conductive tubes which are connected with inlet and outlet headers at opposite ends of each module, the respective headers being adapted for interconnection with suitable inlet and outlet manifold means. In order to adapt the heat exchanger for operation in a high temperature and high pressure environment and to provide access to all tube ports at opposite ends of the tube bundle, a spherical tube sheet is arranged in sealed relation across the chamber with an elongated duct extending outwardly therefrom to provide manifold means for interconnection with the opposite end of the tube bundle.

Donald W. Culver

Papers

Modular heat exchanger