After the large blow molding equipment arrives at the manufacturer, the design and manufacture have been finalized. The optimization of the equipment maintenance and maintenance determines the life of the equipment and the extension or advancement of the blow molding machine overhaul period. The selection of hydraulic oil and the optimization of the conditions of use are one of the tasks that equipment manufacturers can do. Usually, the equipment used in the equipment factory instructions generally specify the hydraulic oil brand number and quantity used by the equipment. Equipment maintenance personnel of the equipment manufacturer need to select according to the requirements of the manual.
1. Selection of hydraulic oil for main hydraulic system
How to use hydraulic oil has many more detailed system introductions in many books on hydraulic technology, but the methods introduced in most books are more complicated, and it is more troublesome for the first-line managers and technicians to find information. Therefore, for large blow molding equipment, since the hydraulic pump used in the main hydraulic system of most large blow molding machines is a vane pump, according to the general selection principle of hydraulic oil, anti-wear hydraulic oil can be directly used.
In addition, oils of different viscosities in anti-wear hydraulic oils may be selected depending on the geographical location of the equipment manufacturer. Generally speaking, the blow molding products factory located in the southern part of China can use N68 anti-wear hydraulic oil; the blow molding products factory located in the north can use N32 anti-wear hydraulic oil. Although the price of anti-wear hydraulic oil is higher than that of ordinary hydraulic oil, in general, because the anti-wear hydraulic oil is used for a longer period of time, it will be economically more economical. Table 54 shows the properties and uses of common hydraulic oils.
Since the main hydraulic system of the large blow molding machine is used at a relatively high pressure and the load on the hydraulic system is relatively heavy, it is recommended to use anti-wear hydraulic oil as much as possible.
2. Optimization of hydraulic oil use conditions of main hydraulic system
The main hydraulic system of the large hollow blow molding machine uses the hydraulic oil mainly including the use temperature of the hydraulic oil and the pollution of the hydraulic oil.
(1) Operating temperature of hydraulic oil The operating temperature of hydraulic oil is one of the most important factors affecting the use of hydraulic systems. Although the range of operating temperature of the hydraulic oil is wide, from the point of view that the hydraulic system is in a good state of use, the hydraulic oil is suitably used at a temperature between 25 and 45 °C. During the use and maintenance of the hydraulic system, the operating temperature of the hydraulic oil should be maintained within this operating temperature range as much as possible. The main factors affecting the operating temperature of hydraulic oil are:
1) Cooling area of the oil cooler. The cooling area of the hydraulic system oil cooler has been determined by the equipment manufacturer. Some equipment manufacturers of hollow blow molding machines at home and abroad use climate as the most important condition to classify equipment. For places with high temperatures throughout the year, oil coolers with a large cooling area should be used, and oil coolers with smaller cooling areas should be used where the temperature is lower. In order to make their equipment widely applicable to all climatic temperature conditions, some blow molding equipment manufacturers use oil coolers with large cooling area for all blow molding equipment, and set an automatic water inlet pipe for oil coolers. The controlled valve automatically controls the flow of cooling water to achieve the purpose of automatically controlling the temperature of the hydraulic oil. The use of automatic control valves to control the flow of cooling water to adjust the operating temperature of hydraulic fluids in the design of hydraulic systems for large blow molding machines has been widely adopted. As shown in the figure, it is a schematic diagram of automatic control of circulating cooling water of oil cooler.