Gas heater

About: Gas heater is a research topic. Over the lifetime, 1799 publications have been published within this topic receiving 6169 citations.

Process and device for producing a CIS-strip solar cell

Abstract: The invention relates to a method of fabricating a strip CIS solar cell and an apparatus for practicing the method. It is the task of the invention to describe a method and an apparatus for providing a technical solution as well as the required layer structure, by which it is possible economically to fabricate adhering CIS solar cells on copper strips. In accordance with the invention the task is solved by a first step of continuously galvanically coating one side of a pre-cleaned copper strip with indium, a second step of very quickly heating the copper strip coated with indium by a contact method with a heated body of graphite and to bring one side into contact with a heated sulfur or selenium containing carrier gas in a narrow gap, a third step of selectively removing by an etching technique the generated cover layer of copper sulfide or selenide, and a fourth step of providing a p + conductive transparent collector or planarizing layer of copper oxide/sulfide. It is a further object of the invention to develop a reactor for practicing the method. The reactor consists of a strip heater made of graphite convexly curved at its gapped surface, a gas heater also made of graphite concavely curved at the gapped surface and quartz glass plates which close a gap set between the strip heater and the gas heater toward the exterior. The strip heater and the gas heater may be separately heated from their interior or their exterior to the necessary process temperatures by radiation heaters.

A Study on the Failure of AISI 304 Stainless Steel Tubes in a Gas Heater Unit

Abstract: This paper investigates a failure in convection section tubes of a gas heater unit in a petrochemical plant. Tubes are made of AISI 304 stainless steel. The failure is reported after 5 years of service at working temperature 500 °C. The failure is in the form of circumferential cracks in the vicinity of the weld. Various characterization techniques, including optical and electron microscopes as well as energy-dispersive X-ray spectroscopy (EDS), were used to study the failure. Results showed that that the damage has initiated in the heat affected zone (HAZ) area parallel to the weld/base metal interface. Cracks have propagated alongside grain boundaries, resulting in an intergranular fracture. The main cause of failure was concluded to be attributable to the grain boundary sensitization and intergranular grain boundary attack due to improper welding and long time exposure of tubes to high temperature. Possible mitigation strategies to minimize similar failures will be discussed.

Sealed gas heater with forced draft and regulation by microprocessor

Abstract: The invention concerns a control device for gas boilers. The overall functions involving control and safety are ensured by a control box (26) with microprocessor which centralizes data collected from the ambient thermostat (27), the temperature sensor (28) on the duct (21) for heating water return, the air output sensor (19), the drawing contact (31), the extraction fan (6) speed sensor (30), and the lighter (24), and it converts them into digital signals that are made to operate the lighter, the circulation pump (19), the gas inlet electrovalve (12) and the extraction fan according to the control data that the microprocessor has memorized. Application for forced draft steamtight gas boilers.