Kingplas - plastic blow molding machine manufacturer
Hollow plastic blow molding machine hydraulic servo system is a hydraulic system with high precision technical requirements. It mainly consists of electro-hydraulic servo valve, relief valve, check valve, inlet and return filter, accumulator, hydraulic manifold, high pressure hydraulic Pump and motor, oil cooler, fuel tank and other components.
The maintenance and maintenance of the hydraulic servo system requires more professional technical knowledge and skills. The repair of some components, such as electro-hydraulic servo valves, requires professional testing equipment and machinery in addition to professional knowledge and skills. high. Therefore, large hollow blow molding machine equipment manufacturers need to have sufficient knowledge and adequate technical preparations to maintain the hydraulic servo system in order to ensure the long-term stable operation of the hydraulic servo system.
In the long-term operation of a large-scale hollow blow molding machine, in addition to the design and manufacturing factors, the stable operation of the hydraulic servo system also requires attention to the following aspects:
1.Ensure the operating quality of hydraulic oil in the hydraulic servo system
The operating quality of hydraulic oil in hydraulic servo system is much higher than that of other hydraulic systems. The hydraulic servo system of a large-scale hollow blow molding machine runs continuously for a long time, and can generally run continuously for 3-6 months. Therefore, it is of great practical and economic significance to ensure the operating quality of the hydraulic servo system oil.
(1) Control of hydraulic oil temperature During the continuous operation of the hydraulic servo system, the temperature of the hydraulic oil will be affected by various factors such as climate, operating conditions, and the temperature of the cooling water. According to the introduction of relevant sections of some hydraulic design manuals, the operating temperature of the hydraulic oil is preferably between 25 and 80 ° C. However, from the long-term use of large hollow blow molding machines, it is found that the temperature control interval of hydraulic oil in the hydraulic servo system is smaller, and the operating temperature of the hydraulic oil is preferably controlled between 25 ~ 40 ° C. When the temperature of the hydraulic oil is in this range, the servo valve, hydraulic pump, accumulator, filter and other components will operate in a relatively good state, which can ensure the stable operation of the hydraulic servo system. If the hydraulic servo system is operated at an oil temperature above 55 ℃ for a long time, the following problems may occur:
1) Accelerate the aging of hydraulic oil. Hydraulic oil will accelerate the oxidative deterioration process due to the rise in oil temperature.
2) After the hydraulic deterioration, it is easy to combine with some small particles and fine fibers washed out in the hydraulic servo system, resulting in strong adhesive dirt. These dirt may be deposited on the spool, control orifice, filter element, etc. of the servo valve, causing the spool to be blocked, the control orifice to be blocked, and the area of the filter element to reduce oil, which may cause the servo valve to malfunction or fail.
3) The temperature rise of the hydraulic oil will directly cause the viscosity of the oil to drop, and the self-lubricating balance inside the servo hydraulic pump will be broken, which will aggravate the wear of the hydraulic pump and cause it to fail in advance, and it will also cause the internal wear of other parts Exacerbation causes premature damage.
4) Accelerate the aging rate of various types of seals of parts and components, especially the seals of PU materials may be faster. Due to the decline of various sealing properties, hydraulic oil leakage will be caused, which will easily cause environmental pollution of the oil and increase the cost of maintenance and oil replacement.
In order to ensure the stable operating temperature of hydraulic oil in the hydraulic servo system, more work can be done on the cooling efficiency of the oil cooler of the hydraulic servo system. Appropriately reducing the temperature of the cooling water and installing an automatic control valve for the cooling water inlet water and appropriately increasing the heat exchange area of the oil cooler are all methods that can control the operating temperature of the servo hydraulic oil. In the case of high temperature at the production site, it is particularly necessary to pay attention to the fluctuation and rise of the temperature of the hydraulic oil of the hydraulic servo system. When the oil temperature is too high, effective measures need to be taken to improve it.
(2) Control of hydraulic oil moisture Because most hydraulic servo systems are designed as open systems, the moisture in the surrounding air can be exchanged into the hydraulic oil through an air filter installed in the oil tank. In addition, if the oil cooler is not well sealed, the cooling water may penetrate into the hydraulic oil; if the oil tank of the hydraulic servo system is not well designed, the water during normal cleaning may leak into the oil tank. After the hydraulic oil is added to the water, the quality of the oil will drop quickly, and a foamy liquid will be formed, which will directly affect the operation of the servo valve, cause the quality of the plastic parison to decrease, and affect the smooth production of the product.
If the oil cooler leaks or seeps in other places during the normal inspection, it needs to be treated in time. If the humidity at the production site is too high, you can take a solution that the operating temperature of the hydraulic oil is not too low, that is, control the oil temperature at 30-40 ° C. In this way, it is possible to evaporate and remove moisture mixed from the air by the temperature of the oil itself.
(3) Control of hydraulic oil pollution For the hydraulic servo system with better sealing, the pollution of hydraulic oil mainly comes from two aspects. The first aspect is the metal wear particles of various parts and some fine particles attached to the parts in the system, which are mixed into the oil under the long-term flushing of the hydraulic oil. Within the first 1-2 years of the new equipment's use This type of pollution accounts for a large proportion; the second aspect is the aging and deterioration of the oil, which is easy to generate carbides. They are combined with the fine particles in the oil, which easily block the small pores in the servo valve and directly affect the servo valve. Works fine.
In order to reduce the impact of oil pollution on the hydraulic servo system, the filter elements of the oil inlet and outlet filters of the hydraulic servo system should be regularly replaced, the filter elements of the precision filters of the servo valve should be regularly flushed or replaced, and the oil of the hydraulic servo system should be regularly checked. Whether the liquid meets the quality requirements (usually checked regularly every year). The oil that does not meet the requirements of the hydraulic servo system needs to be replaced in time. The oil must be changed in accordance with the relevant operating procedures.
(4) Selection of hydraulic oil For the hydraulic servo system, the quality of the hydraulic oil is a key factor that affects whether the servo hydraulic system can be used normally. Never use a second refined oil as a servo in use. As the hydraulic oil, anti-wear hydraulic oil with a better brand must be selected, so as to effectively ensure the long-term stable operation of the servo hydraulic system.