The main reason of fine heat of hydraulic system of fine concrete pump

1 fine stone concrete pump design unreasonable, resulting in the heating of the hydraulic system and its exclusion (1) the improper selection of hydraulic oil number can cause heating of the hydraulic system The selected hydraulic oil at low oil temperatures, the system work properly, but After working for a period of time, the oil temperature will increase and the viscosity of hydraulic oil will drop, resulting in the increase of internal system leakage. With the increase of leakage, the increase of oil temperature will promote the vicious cycle of oil temperature. The solution is: According to the system load and normal operating temperature requirements, select the appropriate viscosity of the hydraulic oil. (2) The fuel tank design is unreasonable, and the heat dissipation effect of the hydraulic system is reduced. The main function of the system heating oil tank is to store hydraulic oil, but it also has the functions of dissipating heat, precipitating impurities and separating water. Fuel tank design is unreasonable, mainly in two aspects: First, the fuel tank volume design is too small, because the concrete pump is a mobile hydraulic equipment, the fuel tank volume is generally double the hydraulic pump flow, so the tank cooling area and oil reserves Second, some of the tanks in the structural design is not reasonable, the suction nozzle and the return pipe port closer, no separator in the middle, thus shortening the oil in the tank cooling cycle and the path of precipitation of impurities, or even Resulting in most of the return oil directly into the suction pipe, reducing the cooling effect of the fuel tank, increasing the oil temperature. The solution is to increase the tank volume appropriately to make the tank volume (1125 ~ 115) Q, and try hard to increase the distance between the suction pipe mouth and the oil return pipe mouth. The partition plate should be set between the suction pipe and the oil return pipe to ensure that the fuel tank Should have cooling power. (3) smaller heat flux, cooler installation location is unreasonable, so that the cooling capacity of the system reduces the cooling capacity of concrete pumps are air-cooled and water-cooled two, users can choose according to the actual situation, but the general use of air-cooled more. Some concrete pumps consider the pressure requirements of the cooler, the cooler is set on the oil return line of the stirring system, and only the oil of the stirring system is cooled. Due to the smaller flow rate of the stirring system, the cooling effect of the entire system is poor, fever. Solution: First, an independent cooling circuit can be used to improve the cooling effect. The second is to set the cooler in the system total oil return to increase the heat flow, improve cooling effect, but this time should pay attention to two problems, the first issue is the cooling fan speed, cooling fan speed can not be too low, Otherwise it will reduce the cooling effect, you can use the motor to drive the fan, or in the total oil return road set a low-voltage drive motor, the motor speed and cooling flow to match, but also can solve the main circuit pressure impact on the cooler pressure capacity; The second problem is the use of motor-driven fan, the main system of the pressure impact on the cooler pressure capacity, this time, the return line and the cooler and installed a low pressure overflow protection valve or one-way valve for cooling The highest pressure protection device. (4) improper selection of hydraulic components, resulting in system heating concrete pump hydraulic system is generally high pressure flow system, if the system of hydraulic components, the main valve, relief valve and sequence valve size selection is not reasonable, can not meet the large Flow requirements, which in use, so that the flow velocity of the valve port flow is too high, resulting in greater pressure loss and the oil temperature, therefore, hydraulic system design in the selection of hydraulic components design, must be based on hydraulic components The maximum working pressure to be sustained, the maximum flow rate passed, and the required range of pressure and flow adjustment to minimize the pressure loss at the valve port and thereby reduce the heating of the system due to the unreasonable selection of hydraulic components. (5) pipeline design, installation unreasonable, resulting in large pressure loss, so that the pressure can be converted into heat energy in the hydraulic system design, piping design and installation can not be ignored, the pipeline diameter should be strictly according to their working pressure and through Flow design, to avoid too small diameter design, resulting in high flow velocity, along the pressure loss is too large, causing fever. At the same time, it should also pay attention to the installation of the pipeline, it is necessary to achieve the appearance of tidy, but also to avoid pipelines gather and the pipeline sharp turn, affecting the natural cooling pipe or cause local pressure loss caused by excessive heat. 2 due to improper use of hydraulic system or component failure, resulting in the heating of the hydraulic system and its exclusion (1) tank hydraulic oil surface below the minimum liquid surface, so that the tank cooling power reduction Concrete pump in use, we should always observe the tank The height of oil level of hydraulic oil always keeps the height of hydraulic oil surface within the normal oil level so as to ensure the heat dissipation effect of the oil tank. When the hydraulic oil level inside the oil tank is lower than the minimum level, it is necessary to oil the oil tank in time. (2) Cooler cooling effect is reduced, so that the fluid temperature rise, cooling system cooler cooling effect may be caused by the following reasons: a cooler internal blockage or surface dirt, resulting in the cooler safety device is turned on, the cooler Therefore, the concrete pump must be regularly checked in use, to clear the cooler, periodically on the cooler surface Dirt removal, to ensure smooth internal cooler and external cleaning, to ensure cooler cooling effect. b The opening pressure of cooler safety valve or check valve is lower than the standard value, so that the cooler safety protection device is turned on when the cooler is not blocked, resulting in overflow shunt, so that the cooling flow of the cooler is reduced. Therefore, before the cooler is used , We must correctly adjust the opening pressure of the safety protection device, in the use of regular inspection to correct the safety protection device opening pressure value. (3) improper adjustment of the hydraulic system pressure, resulting in system heat In the concrete pump hydraulic system, due to the performance requirements, the system often have safety valves, relief valves and sequence valves. If the safety valve pressure is too low, the safety valve will be frequently opened, resulting in overflow loss, resulting in system fever; if the pressure is too high, it will increase the system leakage, the system fever, therefore, should be hydraulic system Load requirements, correct calculation and adjustment of safety valves and pressure values ​​to ensure that the system operates within the specified pressure range. When the main pump of the pump system is a closed system, the heat exchange circuit must be installed in the pumping system. The set pressure of the relief valve in the heat exchange circuit should be taken seriously. If the set pressure is too low, the pump hydraulic pressure Cylinder commutation increases, set the pressure is too high, will make the overflow loss is too large, the system temperature is too high. Therefore, we should reasonably determine the heat exchanger circuit relief valve adjustment pressure value, the general adjustment value of the relief valve (1 ~ 115) MPa, pumping system charge circuit working pressure of 215MPa. When the concrete pump hydraulic system When setting the sequence valve, we must understand the working characteristics of the sequence valve, the correct sequence valve working pressure.