U tube heat exchanger is suitable for the large temperature difference between tube side and shell side. The shell side media is easy to scale and needs cleaning, while the tube side media is clean and not easy to scale. It is also suitable for high temperature, high pressure, fluid corrosive working conditions.
Each heat exchange tube is bent into U-shape, the two ends are fixed in the upper and lower areas of the same Tube Sheet, and divided into two chambers of inlet and outlet with the partition in the tube box. This kind of heat exchanger completely eliminates the thermal stress, the structure is simpler than the floating type, but the tube side is not easy to clean.
The number of tubes is small, the utilization of the tube sheet is not frequent, and the shell side fluid is easy to short circuiting, which is unfavorable to heat transfer. If there is a leak or damage in the tube, the external U-tube can be replaced, while the broken inner tube can not be replaced, only plugged, and one broken U-tube means two broken, so the U-tube easily scrapped.
U Tube Heat Exchanger,Beu Heat Exchanger,U Type Heat Exchanger,U Tube Type Heat Exchanger Guangdong Jiema Energy Saving Technology Co.,Ltd , https://www.jmheatexchanger.com
The Tianjin Inspection and Quarantine Bureau reminds relevant importers that they must attach great importance to the new environmental control standards for imported wastes, avoid the pollution caused by the goods to China's environment, and the economic losses caused by the return of goods that do not meet environmental control standards.
According to reports, the new standard was issued on the basis of the original standard in 1996, combined with the current economic and social situation, and has the effect of enforcement. Compared with the original standard, the new standard imposes more stringent restrictions on the banned substances, strict controls, inclusions, and radioactive detection of imported waste raw materials.
The new standard provides for the radioactive detection of all imported waste raw materials on the basis of radioactive detection of only scrap metal on the basis of the original standard; the general restriction on the amount of inclusions in waste paper is strictly controlled from no more than 2.5% to no more than 1.5%. Strictly limit the percentage of inclusion control from the original not more than 0.03% to no more than 0.01%. At the same time, the “Control Standards and Requirements†specifically added “The materials that can be recycled and used for imported waste hardware and electrical appliances should not be less than 80% of the total mass of the waste hardware appliances, and the content of available metals should not be lower than the total of waste hardware and appliances. 60% of the quality "etc.
It was also learned that in 2005, the Tianjin Inspection and Quarantine Bureau carried out inspection and quarantine on 32,419 batches of imported waste raw materials at the Tianjin Port and detected 81 batches of wastes that did not meet China's environmental control standards, including polyethylene waste. The price of plastic raw materials soared last year, which stimulated the surge in imports of waste plastics. Since the Spring Festival, the price of recycled materials has been on an upward trend, which has stimulated the scrap market again. At present, the quantity of imported plastics has only increased.
The "Environmental Protection Control Standard for Solid Wastes Imported as Raw Materials" promulgated jointly by the AQSIQ and the State Environmental Protection Administration has been implemented since this month. The implementation of the standard will further standardize the import and management of raw materials that can be used as raw materials to prevent environmental pollution caused by imported waste materials.