Preventing tube failure in boilers

The erosion-prone sections of the tubes in a circulating fluidized bed boiler are provided with a locally thickened sidewall without forming discontinuities on the outer surface of the tubes. This can be accomplished, for example, by replacing the erosion prone portion of the tube with a section having a smaller inside diameter, but the same outside diameter, or by replacing the erosion prone portion of the tube with a section having a thicker sidewall, but the same inside diameter, and smoothing over the outside discontinuity with an alloy coating. A useful alloy coating is also disclosed which can be used for this and other applications.

Method for forming a coating on a substrate by thermal spraying

A thermal spraying method involves the creation of a coating comprising titanium wire in the presence of nitrogen. The apparatus of the invention comprises a nozzle which has a cylindrical throat, with feedstock guides which guide the feedstock wires to a point of intersection in the throat. A current is passed through the wires to cause an arc in the throat, and a nitrogen rich gas under pressure is forced through the throat, generating a spray of molten particles which is used to coat a substrate. In a variation of the method, one of the feedstock wires comprises a binder metal, which produces a coating having enhanced toughness.

Scaffolding

A scaffolding element used in conjunction with an upright alignment member, such as a pole. The scaffolding element having at least one connector member at each end portion thereof. The opposing connector members are oriented transversely relative to one another, such that the connector members of adjacent scaffolding elements can interlock at right angles to one another, forming a structure of interlocking scaffolding elements. The connector members can be formed from a metal plate or can be a casting, for example.

Thermal spraying method and apparatus

A thermal spraying method involves the creation of a coating comprising titanium wire in the presence of nitrogen. The apparatus of the invention comprises a nozzle which has a cylindrical throat, with feedstock guides which guide the feedstock wires to a point of intersection in the throat. A current is passed through the wires to cause an arc in the throat, and a nitrogen rich gas under pressure is forced through the throat, generating a spray of molten particles which is used to coat a substrate. In a variation of the method, one of the feedstock wires comprises a binder metal, which produces a coating having enhanced toughness.

PREVENTING TUBE FAILURE IN BOILERS

The erosion-prone sections of the tubes in a circulating fluidized bed boiler are provided with a locally thickened sidewall without forming discontinuities on the outer surface of the tubes. This can be accomplished, for example, by replacing the erosion prone portion of the tube with a section having a smaller inside diameter, but the same outside diameter, or by replacing the erosion prone portion of the tube with a section having a thicker sidewall, but the same inside diameter, and smoothing over the outside discontinuity with an alloy coating. A useful alloy coating is also disclosed which can be used for this and other applications. 1. A tube comprising a tubular sidewall , a first end , a second end , a length as measured between the first end and the second end , a longitudinal axis , and a non-uniform wall thickness along a portion of the length ,wherein the sidewall has a thickened wall thickness area in the portion of the tube having the non-uniform wall thickness, and the thickened area being axially elongated and gradually tapering axially to an area of the tube having a uniform sidewall thickness.2. The tube according to wherein the thickened wall thickness area comprisesa longitudinally elongated tapering section which tapers toward the longitudinal axis of the tube at a maximum average angle in the range of 0.05 to 1.5 degrees over the length of the tapering section.3. The tube according to wherein the tubular sidewall comprisesa first layer and a second layer,wherein said first layer is tubular and has a uniform sidewall thickness, and the second layer is positioned radially outwardly from the first layer and is generally saddle-shaped.4. The tube according to wherein the second layer has an area of maximum thickness as measured radially from the longitudinal axis of the tube claim 3 , the maximum thickness area of the second layer being at least 0.060 inches thick claim 3 , the area of thickness of at least 0.060 inches having a length as measured ...

Thermal spraying equipment

Verfahren und vorrichtung zum thermischen spritzen

Gerüst

Scaffolding.

Kühlsystem

A cooling system

A cooling system for apparatus essentially redirects the compressed or induced air flow normally used by the apparatus to cool heat exchange members which are in thermal connection with a plurality of parts of the apparatus to be cooled. The cooling system is typically used to cool diodes or thyristors of the apparatus. The compressed or induced air flow is directed through each heat exchange member before being directed back to the remainder of the apparatus. The prototype cooling system was designed for an arc spray device.

A cooling system

A cooling system for apparatus essentially redirects the compressed or induced air flow normally used by the apparatus to cool heat exchange members which are in thermal connection with a plurality of parts of the apparatus to be cooled. The cooling system is typically used to cool diodes or thyristors of the apparatus. The compressed or induced air flow is directed through each heat exchange member before being directed back to the remainder of the apparatus. The prototype cooling system was designed for an arc spray device.