Abstract: The structural integrity and coolant flow characteristics of a heat exchanger which employs double tubes is improved by providing a structural element, which defines an annular chamber through which coolant may flow, about the internal structure which supports the opposite ends of the double tubes. The outer wall of the structure which defines each of the annular chambers in alignment with and welded to, a casing which in part defines a gas entry or exit chamber axially disposed at a first side of the internal tube support structure and to an external support ring located axially at the other side of the internal tube support structure.

Abstract: Thermal decoking of cracking gas coolers which operate with low gas pressure is accomplished by controlling the temperature of a cleaning gas delivered to the cooler. The temperature control is achieved by mixing a cleaning gas, which has been heated in a cracking oven, with a stream of relatively cool cleaning gas upstream of the cooler.

Abstract: In a process for the mechanical cleaning of heat exchange surfaces of an evaporator or superheater of a steam generator, a dust-laden hot waste gas being passed through the steam generator, the formation of adhesive deposits on the heat exchange surface is prevented by lowering surface temperature at least at the beginning of a cleaning cycle. The surface temperature will be reduced to below the softening temperature of the material being deposited whereby such material forms hard deposits which may be loosened from the surfaces by mechanical means such as vibration.

Abstract: A heat exchanger having coaxial inner and outer conduits is characterized by a flow intercepting body which extends into the inner conduit to thereby divide the length of the heat exchanger into two sections with different heat exchange characteristics. Adjustment of the temperature of gases exiting the heat exchanger may be accomplished by varying the ratio of the lengths of the two sections of the heat exchanger.

Abstract: In order to create an economic two-stage heat exchanger system which is capable of cooling cracked gas from short-term splitting furnaces, which is capable of flexible operation utilizing changeable charging stock, the two stages of the heat exchanger are integrated in one device, in order to avoid the necessity of delivering the cracked gas to a second stage via long, hot pipelines. In addition, the system has the capability of switching the heat exchanger plant over to a single-stage operation.

Abstract: An adaptive control technique, in which the duty cycle of a vibrational cleaning device for the heat exchange surfaces of a steam generator is automatically adapted to the current state of dirt accumulation on the surfaces. To ascertain the degree of dirt accumulation, the number of strokes of the drive cylinder of a fluidic actuator of the vibrational device is measured in a short interval at the beginning of each cleaning cycle and compared with a reference value. The cleaning cycle length or vibration period within the cycle is either lengthened or shortened commensurate with the results of the comparison and in this way the duty cycle of the vibrational device is continuously adapted to the current need for cleaning.

Abstract: A heat exchanger for cooling a hot process waste gas has an interior gas-flow pipe which is surrounded by a cooling jacket defined by a plurality of parallel pipe segments which are spaced from another and from the gas flow pipe. The pipe segments, through which a coolant flows, are mechanically and thermally interconnected to one another and to the gas flow pipe by means of a body of material having a thermal conductivity which is greater than that of the material from which the pipe segments are fabricated.

Abstract: A heat exchanger includes banks of double-pipe elements connected to oval headers, the opposite ends of which are connected by round transition elements to main headers. Each oval header and the respective transition elements are formed from a single, integral member, initially a cylindrical pipe, without connecting welds. The outer ends of the transition elements are reduced to form nipple elements for attachment to the main headers. The nipple elements have a greater wall thickness than the transition elements.

Abstract: A heat exchanger includes banks of double-pipe elements connected to oval headers, the opposite ends of which are connected by round transition elements to main headers. Each oval header and the respective transition elements are formed from a single, integral member, initially a cylindrical pipe, without connecting welds. The outer ends of the transition elements are reduced to form nipple elements for attachment to the main headers. The nipple elements have a greater wall thickness than the transition elements.