Summary    As we all know, the filling of liquid chlorine is a more complicated process. Due to the special physical and chemical properties of liquid chlorine, the measurement accuracy of its filling flow is not high, which is also a prominent problem in the field of flow measurement. This paper combines the experience and lessons learned from the use of mass flowmeters in the liquid chlorine filling and metering process for many years, and puts forward several suggestions for the measurement of liquid chlorine filling for reference by peers. There are many products classified in this section of Folding Machine For Shirts. They are focused on folding all kinds of shirts, Polo, thin jacket,thin sweater. Attention: The following garment are applied to this auto folding packing machine. Like, garment designed with many accesories, too thick coat,suits t shirts. Folding Machine With Stacking Device,Clothes Stacking Machine,Automatic Folding Machines,Auto Folder ShenZhen Lingchuang Automated Technology Co.,Ltd , https://www.szlcautos.com
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Key words    Liquid chlorine filling measurement,  Mass flowmeter
The HC series Coriolis mass flowmeter manufactured by our company has been applied in the liquid chlorine filling and metering process of some chlor-alkali industries in five provinces and regions in China since 2011 . Now we introduce its experience in use as follows, for the same industry and the general user reference:
1. The significance of flow metering in liquid chlorine filling
Liquid chlorine is a yellow-green transparent liquid with a composition of Cl2>96% (vol) , H2O<0.015% (wt) . The relative density is 1.468 ( 0 °C ), the boiling point is -34.5 °C , the melting point is -100.98 °C , and the molecular weight is 70.91 . Under normal pressure, vaporized into gas, 1kg of liquid chlorine vaporized to obtain 300L of gaseous chlorine (dry chlorine). It has a stifling scent and has a strong irritating odor and corrosiveness.
For any liquid chlorine container, the fill factor must not exceed 80% . Because the low temperature chlorine entered the container, for example 38 ℃, a pressure of 1.0Mpa.g. If the liquid chlorine is in a stationary and non-flowing state, the liquid chlorine will continue to absorb the heat from the outside air to increase the temperature, and the vaporization will cause the volume to expand; if the liquid chlorine is filled in the container, there is no free space to allow it to expand, and the liquid With its incompressible nature, liquid chlorine will generate a tremendous pressure as temperature rises, causing the container to burst. If the container is filled with the liquid chlorine, can not freely expand when the temperature rises to 50 ℃, pressure can reach 50Mpa.g. This will greatly exceed the allowable pressure that typical pressure vessels can withstand. Liquid chlorine cylinder filling factor also prohibited more than 80%, chlorine tanker design temperature is 50 "C.
The liquid chlorine tank has a phase change during filling and is an endothermic process. The filling temperature is generally lower than room temperature. After filling. Tank truck temperature rise is slow, then the volume of liquid chlorine in the tank vehicle volume percentage increases. The gas phase becomes smaller. If overfilled. A rise in temperature will result in an increase in pressure. At this time, the increase in internal pressure will not be the law of rising saturation vapor pressure. High pressure tank tanks are at risk of explosion.
China has strict regulations on liquid chlorine containers and their filling, and there are *, fire control, safety supervision and other departments in the transport sector to carry out strict supervision and inspection, the punishment for excessive filling is very large. For this reason, real-time supervision is required during liquid chlorine filling to prevent overfilling. Once excessive overfilling is found, the loss of manpower, material resources, and financial resources required for penalties and unloading can be significant.
This shows that the measurement of the liquid chlorine filling process is very important.
2. Error Analysis of Liquid Chlorine Tank Filling Process
2.1 The error of the liquid chlorine tank filling device itself
So far, the flowmeter has only been used on the filling device of a liquid chlorine tanker. The processing and production of the tank filling device is basically completed by the user himself. Therefore, the design, selection and configuration of the structure, control section, and valves of each user's charging device are different. Although the metering accuracy is higher. However, the measurement error caused by the above reasons is far greater than the error of the flowmeter itself. For example: Because the user chooses valves that are pneumatic, electric, and manual. When the filling starts, if the valve opens too fast, the pressure of the liquid chlorine in front of the valve will drastically drop, resulting in vaporization of liquid chlorine.