The heating of the hydraulic system can be divided into two categories according to the heating reasons: one is the heating caused by the design reasons; One is due to the failure or improper use of hydraulic components, resulting in heat. Obviously, the cause of fever is different, and the way of elimination is not the same.
1. The design is unreasonable, resulting in the heating and elimination of the hydraulic system
(1) Improper use of the oil number of the hydraulic oil may lead to the heating of the hydraulic system when the selected hydraulic oil is at a low oil temperature, the system works normally, but after the system works for a period of time, the oil temperature is high, and the viscosity of the hydraulic oil is reduced, resulting in the internal leakage of the system to increase, and the increase of the oil temperature is promoted with the increase of the leakage, resulting in a vicious cycle of oil temperature. The solution is to select the hydraulic oil suitable for viscosity according to the load of the system and the normal working temperature.
(2) The tank design is unreasonable, so that the heat dissipation effect of the hydraulic system is reduced. The key role of the heating tank is to store hydraulic oil, but it also has the effect of cooling, settling impurities, and separating water. The tank design is unreasonable, mainly manifested in two levels: First, the tank volume design is too small, because the concrete pump is a mobile hydraulic equipment, the tank volume is generally twice the flow of the hydraulic pump.
Therefore, the total area of heat dissipation and storage capacity of the tank are small; The second is that some fuel tank structure types are not reasonable design, the suction pipe mouth and the return pipe mouth are close, and there is no baffle in the middle, which reduces the cooling circulation system of hydraulic oil in the oil tank and the way of settling impurities, and even leads to most of the pump oil directly into the suction pipe, so that the heat dissipation effect of the oil tank is reduced and the oil temperature is high. The solution is: moderately increase the tank volume, so that the tank volume is (1125~115) Q, and increase the distance between the suction pipe and the return pipe as much as possible, and the baffle should be set in the middle of the suction and return pipe to ensure the heat dissipation power required by the tank.
(3) The heat dissipation flow is small, the installation position of the cooler is unreasonable, so that the system heat dissipation capacity is reduced, the cooling method of the concrete pump has two kinds of air cooling and water cooling, customers can use according to the specific situation, but generally choose more air cooling. Some concrete pumps take into account the pressure requirements of the cooler, the cooler is set in the pump oil channel of the mixing system, and only the hydraulic oil of the mixing system is cooled, because the flow rate of the mixing system is small, so the cooling effect of the whole system is poor, so that the system heats up.
Solution: First, a separate cooling circuit can be selected to improve the cooling effect. The second is to set the cooler in the total pump oil channel of the system to increase the heat dissipation flow and improve the cooling effect, but at this time should pay attention to two problems, the first problem is the speed of the cooling fan, the speed of the cooling fan can not be too low, otherwise it will reduce the cooling effect, you can use the motor to drive the fan, or set a bottom pressure drive motor in the total pump oil channel. The speed of the motor is consistent with the heat dissipation flow, and the harm of the pressure impact of the main circuit on the pressure resistance of the cooler can be solved. The second problem is that if the motor is used to drive the fan, the pressure impact of the main system is harmful to the pressure resistance of the cooler. At this time, a bottom pressure relief maintenance valve can be installed on the pump oil line and the cooler, or this product can be the highest pressure resistance maintenance of the cooler.
(4) Improper selection of hydraulic components, resulting in high pressure and large flow system of concrete pump hydraulic system is generally high pressure and large flow system, if the hydraulic components in the system, mainly hydraulic reversing valve, relief valve and sequence valve specifications and models are not reasonable, can not consider large flow regulations, and then in the application, the valve flow rate is too high, resulting in great pressure damage and high oil temperature.
Therefore, in the design of the hydraulic system, when the selection of hydraulic components is designed, it is necessary to select components according to the highest working pressure undertaken by the hydraulic components, the larger flow rate according to it and the specified pressure and flow adjustment category, to minimize the valve pressure damage, and then reduce the system heating caused by the unreasonable use of hydraulic components specifications.
(5) Unreasonable pipeline design and installation, resulting in large pressure loss, so that the pressure can be converted into energy in the design of the hydraulic system, the design and installation of the pipeline can not be ignored, each pipeline should be strictly designed according to its working pressure and flow rate, to prevent the design of the pipe is too small, resulting in high flow rate, pressure loss pressure damage is too large, resulting in heat. In addition, we should also pay attention to the installation of the pipeline, not only to ensure that the appearance is neat, but also to prevent the pipeline aggregation and the sharp bend of the pipeline, which harms the heat dissipation of the pipeline or causes excessive pressure damage to some of the heat.
Yining hydraulic
2. Due to improper use of hydraulic system or component failure, resulting in heating and removal of hydraulic system
(1) The hydraulic oil level in the oil tank is lower than the minimum level, so that the heat dissipation power of the oil tank is reduced. During the application of the concrete pump, it is necessary to observe the oil-level aspect ratio of the hydraulic oil in the oil tank at any time, and always keep the oil-level aspect ratio of the hydraulic oil in the normal oil volume, so as to ensure the heat dissipation effect of the oil tank. When the hydraulic oil level in the oil tank is lower than the minimum level, it is necessary to drop oil into the oil tank immediately.
(2) The cooling effect of the cooler is reduced, so that the temperature of the hydraulic oil rises, and the cooling effect of the system heating cooler is reduced, which may be caused by the following reasons: a1 cooler internal blockage or surface dirt more, resulting in cooler safety device open, cooler overflow reduced, reduce the heat dissipation flow, or cooler ventilation is poor, the cooler cooling heat transfer coefficient is reduced, cooling effect is reduced, therefore, the concrete pump in the application must be regularly checked, feed the cooler, on time to eliminate the cooler surface dirt. Ensure that the inside of the cooler is unobstructed and the outside is cleaned to ensure the effect of the cooler.
b1 cooler safety valve or the opening pressure of this product is lower than the indicated value, so that the cooler safety protection device is opened when the cooler is not blocked, resulting in overflow separation, so that the cooler heat flow is reduced, therefore, the cooler before application, must properly adjust the opening pressure of the safety protection device, in the application to check regularly, calibrate the opening pressure value of the safety protection device.
(3) Improper pressure adjustment of the hydraulic system leads to system heating. Because of the performance requirements, the system is usually equipped with safety valves, relief valves and sequence valves. If the pressure of the safety valve is adjusted too low, the safety valve will open frequently, resulting in overflow damage, resulting in heating of the system; If the pressure adjustment is too high, it will increase the leakage in the system and cause the system to heat up. Therefore, the safety valve and pressure value should be properly measured and adjusted according to the load requirements of the hydraulic system, so as to ensure that the system works within the required pressure range.
