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This post was last edited by sdwfsgyykai on 2019-11-12 07:55. A chemical company founded in 1939, it is a large-scale chlor-alkali enterprise that relies on salt electrolysis as its foundation and aims to develop the fields of marine chemistry and petrochemicals; it produces various products such as caustic soda, polyvinyl chloride resin, propylene oxide, polyethers, liquid chlorine, and synthetic hydrochloric acid. For a company that has obtained ISO9002 quality system certification, in order to achieve and maintain an excellent standard of product quality, a chemical company carried out a series of reforms and innovations. Technologically, production facilities for ion-exchange membrane caustic soda, propylene oxide, and PVC produced by the ethylene oxychlorination method, all of which are at the international advanced level, have been introduced one after another. In the production of its key products such as caustic soda, polyvinyl chloride resin, propylene oxide, and polyethers, microcomputer-based automatic control is employed; the four main parameters in the company’s production processes—temperature, pressure, flow rate, and liquid level—are monitored in real time and managed centrally. Since enterprises have many areas where \"hazardous chemicals\" are stored and used, these chemicals mainly include vinyl chloride, liquefied gas, propylene, phenol, ABS oligomers, butadiene, VCM, and VCM monomers. High requirements are placed on safety and environmental protection; therefore, measuring instruments must operate without any faults, and even in the event of a fault, they must not pose risks such as combustion, explosion, or leakage. This imposes even higher safety requirements on such measuring instruments. http://www.dhechina.com/ueditor/php/upload/image/20170615/1497519089315797.png In the past, magnetic flap level gauges, differential pressure level gauges, and imported radar level gauges from certain brands were used on these tanks. Due to the presence of deposits in some fluids and impurities in others, especially the problem that VCM monomer is volatile and prone to self-polymerization, level measurement has always been a challenge. With magnetic flap level gauges and differential pressure level gauges, the connecting pipes get blocked after being in use for a while, requiring cleaning, maintenance, and re-calibration ； The emission port of the radar level gauge is covered by volatiles and self-polymerizing substances; before maintenance, it is necessary to empty the tank and replace the contents, a process that is very complex and requires a lot of effort, thus having an adverse impact on the company’s daily operations. In 2000, a new type of measurement method was discovered online: isolated level measurement. As a result, a new kind of level gauge was developed – the ELL sonar external level gauge. Its installation, calibration, and maintenance do not require emptying the tank, using open flames, or making holes in the tank. Due to its easy installation – all that is needed is to attach a sensor to the bottom outside the tank and connect it to a transmitter, which then displays the liquid level – and since calibration does not affect production, it was decided to give it a try. In March 2001, Dinghua Electronics Company brought instruments for testing and chose directly chlorine vinyl monomer (VCM) storage tanks, where it is difficult to measure the liquid level. The fluid in such tanks is volatile and tends to polymerize, and there are sediment layers at the bottom of the tanks; therefore, an ELL sonar-type external level gauge model AE was installed on these tanks. After using it for 3 months, the gauge has operated stably, provided accurate level readings, and offered reliable remote transmission – fully meeting our requirements for level measurement. http://www.dhechina.com/ueditor/php/upload/image/20170615/1497519106475470.png Since 2002, the company has installed ELL sonar-based external level gauges from Dinghua Electronics on all its vinyl chloride horizontal tanks, as well as on its liquefied gas storage tanks; in total, ten such gauges have been installed. They have been in use for 15 years now, with virtually no failures. In 2010, 9 new storage tanks were built, all of which were equipped with the external level gauges manufactured by Dinghua Electronics, thereby solving the problem of measuring liquid levels in ABS oligomer storage tanks. The ELL sonar-type external level gauge has become the standard instrument for measuring liquid levels in tanks storing hazardous chemicals. I sincerely hope that Xi’an Dinghua Electronics Co., Ltd. will continue to develop and provide users with more modern instruments!