A cooling system includes a heat exchanger having one or more rows of multiple flat tubes, louvered fins disposed between pairs of flat tubes, and special header tube connections to form a counter flow heat exchanger. Heat exchangers having multiple rows may be placed near or close to the server racks and may be in fluid communication with an outdoor heat exchanger having one or more rows. A single-phase fluid is pumped through a fluid circuit or loop, which includes the heat exchangers at the server racks and the outdoor heat exchanger. The single-phase fluid circuit including the heat exchangers at the IT racks may alternatively be in thermal communication with a water circuit that includes an outdoor fluid cooler. The flat tubes can be formed tubes with one or more channels, or extruded tubes with multiple channels. The heat exchangers include header tubes/connections, which facilitate easy fabrication and connection between rows and inlet/outlet, and lower the pressure drop.

An aluminum alloy brazing sheet has a 3XXX, 1XXX or 6XXX core, an interliner and a 4XXX brazing layer without added Mg. The interliner has Bi and Mg, the magnesium migrating to the surface of the brazing sheet during brazing and reducing the aluminum oxide to facilitate brazing without flux in a controlled inert atmosphere with reduced oxygen.

A heat exchanger includes: flat tubes; a plate attached to the flat tubes; a medium tank configured to form a medium flow path by covering openings of flat tubes; and a reinforcing member to reinforce the openings. The reinforcing member includes a pair of leg portions and a connection portion that connects the leg portions. An insertion amount of the leg portions into the opening is larger than a sum of a gap between the connection portion and an inner surface and a length from the opening to a position corresponding to a brazed portion between the flat tube and the plate, or when a protruding portion protruding in a direction opposite an insertion direction is provided in the connection portion, larger than a sum of a gap between the protruding portion and the inner surface and a length from the opening to the position corresponding to the brazed portion.

A method of making a heat exchanger that includes sealing tubes to header slots and brazing the tubes to the header slots. The method further includes coupling a cover to the header to cover a liquid-side surface of the header and to cover ends of the tubes, and applying flux to an air-side surface of the header and to the tubes. Coupling the cover to the header is performed after sealing the tubes to the header slots and coupling the cover to the header is performed before applying flux to the air-side surface of the header and to the tubes. Applying flux is performed before brazing each of the tubes to the header slots and sealing each of the tubes to the header slot includes sealing a perimeter of each of the tubes to the header slot.

An aluminum heat exchanger includes first and second plates with inner and outer surfaces, which are joined by brazing and define at least one fluid flow passage. The first and second plates each comprise a core layer of aluminum or an aluminum alloy having a melting temperature greater than an aluminum brazing temperature. The first plate also includes a first outer clad layer defining the outer surface of the first plate. The first outer clad layer is solderable to a metal layer of an object to be cooled and includes nickel or copper. A second outer clad layer is located between the first outer clad layer and the core layer and is roll bonded to at least the second outer clad layer. A manufacturing method includes brazing first and second plates, where the layers of the first plate are roll bonded and the first plate is optionally formed before brazing.

A tool system controls and prevents gaps during processing of assemblies at elevated temperature. Gaps are prevented from arising at joints between components during temperature changes. The tool system includes a lever arm having a body, a connection configured to allow the body to pivot, a cam surface defined by the body and configured to engage the second component, and a weight arm extending from the body and over the second component. In response to movement of the second component, the lever arm is configured to pivot at the connection while the weight arm is configured to generate a force transferred through the body to the second component to maintain contact at the joint between the first component and the second component. A rod may be connected with the lever arm for added weight.

A screen for brazing a heat exchanger including a plurality of core plates and a base plate. The plurality of core plates may be formed from an aluminum alloy brazing sheet containing magnesium and may have a shape having a taper portion at a periphery. The base plate may be larger and thicker than a core plate of the plurality of core plates. The plurality of core plates and the base plate may be heated and brazed under an inert gas atmosphere. The screen may include a metal tube enclosing a stacked body of the plurality of core plates. The tube may follow the outer border of the plurality of core plates such that a specific minute gap is defined between an inner wall face of the tube and a tip edge of the taper portion.

An aluminum brazing sheet having a multi-layer structure of two layers or more, an aluminum alloy brazing material being located on an outermost surface by being cladded on one surface or both surfaces of a core material, and the aluminum brazing sheet being applied to brazing in which the aluminum brazing sheet is bonded to a member to be brazed made of aluminum or an aluminum alloy without using a flux in a non-oxidizing atmosphere without decompression. The brazing material is made of an Al—Si—Mg—Sn brazing material containing, by mass %, 0.01% to 2.0% of Mg, 1.5% to 14% of Si, and 0.005% to 1.5% of Sn, and in observation in a surface direction before brazing, there are more than 10 Mg—Sn compounds with a circle equivalent diameter of 0.01 μm or more and less than 5.0 μm in the Al—Si—Mg—Sn brazing material per 10000 μm.sup.2 field of view.

A refrigerant pipe constituting a refrigerant circuit of a refrigeration apparatus, includes: a pipe body made of stainless steel; and a first connecting tube made of copper or a copper alloy and that is configured to connect a first different refrigerant pipe to the refrigerant pipe. The first connecting tube is connected to an outer circumferential surface of a first end of the pipe body in a pipe axis direction of the pipe body. The first connecting tube overlaps with the pipe body in a pipe diameter direction in an entirety of the first connecting tube in the pipe axis direction.

In a film formation step of a brazing method, a metal brush formed by bundling a plurality of metal wires is brought into contact with a film formation target portion of a workpiece. Here, the film formation target portion is a portion that includes a joining target portion and a brazing-material-allowed portion but does not include an avoidance portion. In this state, the film formation target portion and the metal brush are relatively moved to each other. Thus, the metal film is formed on the film formation target portion. In a brazing step, the joining target portions are joined in a state where a brazing material is arranged on the joining target portion and the brazing-material-allowed portion.