Cylinder Heat Carrier Paint Heating System Applied Research

With the wide application of liquefied petroleum gas (LPG) in cities, LPG bottle manufacture industry developed very fast from the early eighties to the end of nighties. From that time, LPG bottle requirement in rural areas keeps increasing, but with the popularization of city gas and the reform of economic system, the need to LPG bottle in cities keeps declining, which results in drastic competition in LPG bottle market. To boost up the ability of competition in markets, LPG bottle manufacturers must take some measures, such as adopting advanced production techniques and advanced managing modes or enlarging its production scale, to lower its production cost. This paper only discusses LPG bottle paint drying, one of its production processes, to look for a lower cost method for it, to replace the conventional and infrared ray paint drying.Limited to historical reasons, conventional paint drying methods for LPG bottle are all infrared ray heating, which has some advantages such as simple system, convenient operation and fast on-off, But it has some disadvantages such as higher energy cost and maintenance costs. Based on wide investigations on the conventional paint drying methods and automobile paint drying, a new method for LPG bottle paint drying is put forward. Furthermore, a devices used for new way has been developed, and at the same time, the method to accessorial equipment selection, computation is presented. The new device consists of paint-drying box, heat carrier boiler, heating pipe, expansion tank, gas separator and oil tank, etc. The data of two applied examples shows that heat carrier paint drying method is able to make painting-drying cost drop by 88%, compared with the conventional one, that it has some advantages such as uniform temperature field, good appearance and lower costs, compared with conventional hot air convection mode.The flow diagram of a LPG bottle paint-drying heating system using heat carrier as heat-medium, which has similar properties as other heat-carrier heating systems, has been improved, which has good effect in avoiding oil-spraying, shortening dehydration time and power-fail protecting etc. After making a series of analysis, calculational methods of expansion tank dimension have been deduced, which takesthe moisture boiling-off of heat carrier into account and accords with real conditions. Some measures, presented in this paper, to prevent heating system from oil-spraying has better effect on the system. On the basis of simplifying, the heat load formula and heat transfer model of paint-drying box is put forward. Exergy efficiency of a heat carrier boiler and its system has been analyzed, which gives the approach to make use of energy.After giving a test to an applied example, a set of main technical parameters has been gained. The test result shows that investment reclaiming period is about 4 or 6 month when taking coal as fuel. If taking fuel-oil or other combustible gases as fuel, the period will be prolonged.