11 precautions for the use of hydraulic pumps

Although the structure of the hydraulic pump in the hydraulic press is very different, there are many problems in the equipment and application.

Servo hydraulic press

(1) Hydraulic pump connection precautions

1 Hydraulic pump of hydraulic press can be used with bearing or flange equipment. The pump and prime mover should be used with the base. Both flange and base shall have satisfactory rigidity. Special note: Plunger pumps with a flow rate greater than (or equal to) 160L/min are not suitable for equipment on the tank.

2 Hydraulic press hydraulic pump and prime mover output shaft should be connected to the elastic coupling. Do not pump the hydraulic pump on the hydraulic pump shaft or gear drive hydraulic press. If a pulley or gear must be attached to the pump, a pair of bearings should be added to the device to drive the wheel or gear. The coaxiality error of bearing and pump shaft should not be greater than Φ0.05mm.

3 Straws should be as short, straight, large, and thick as possible. The suction pipe should generally be set with a coarse filter, whose nominal flow rate is not less than twice the pump flow rate (filtration accuracy is generally 80-180μm). The discharge pipe of the hydraulic pump of the hydraulic press should be directly connected with the oil tank, and the back pressure of the oil return should not exceed 0.05MPa. The suction nozzle and return nozzle of the oil pump should be less than 200mm below the minimum oil level of the tank. Special care should be taken not to accept the equipment oil filter on the suction line of the plunger pump. The diameter of the stop valve on the suction pipe should be greater than the diameter of the suction pipe. The length of the suction pipe should be less than 2500mm, and the pipe elbow should not exceed 2.

4 Hydraulic pump inlet and outlet should be firm, sealing equipment should be firm. Otherwise, air inhalation or oil leakage will occur, affecting the function of the hydraulic pump of the hydraulic press.

5 The self-priming height of the hydraulic pump does not exceed 500mm (or the inlet vacuum does not exceed 0.03MPa). If the oil pump is selected, the oil pressure shall not exceed 0.5MPa. When the oil pressure exceeds 0.5MPa, the pressure seal should be replaced. For plunger pumps, the self-priming method should be used whenever possible.

6 Before installing the hydraulic pump of the hydraulic press, check whether the hole depth of the equipment is greater than the shaft extension length of the pump to prevent the shaft phenomenon. Otherwise, the pump will be incinerated.

(2) Hydraulic pump operation precautions

1 When the hydraulic pump of each hydraulic press manufacturer starts, it should be moved several times, and the oil flow direction and sound direction are normal. After 5 to 10 minutes of low-voltage operation, it will enter the normal operation state. Before starting the plunger pump, the discharge port on the housing must be connected to the pump and filled with clean working oil.

2 The viscosity of the oil changes due to the influence of temperature, and the viscosity of the oil temperature rises. Therefore, the oil temperature needs to be kept below 60°C. In order to enable the hydraulic pump of the hydraulic press to operate stably at different operating temperatures, the selected fluid should have a lower oil temperature characteristic viscosity, and have better chemical stability and anti-foam function. It is recommended to use L-HM32 or L-HM46 (GB11118.1-94) anti-wear hydraulic oil.

3 Fluid must be clean and must not be mixed with mechanical impurities and corrosive substances. The hydraulic system without a filter on the suction line must be fed through an oil filter (less than 25μm).

The maximum pressure and maximum speed of the hydraulic pump refer to the peak value allowed in a short period of time, which should be prevented from being used for a long time, otherwise it will affect the service life of the hydraulic pump of the hydraulic pump.

5 Hydraulic pump normal working oil temperature of 15 ~ 65℃. The maximum temperature on the pump housing is generally 10 to 20°C higher than the oil temperature at the pump inlet in the tank. When the oil temperature in the tank reaches 65°C, the maximum temperature of the pump housing does not exceed 75 to 85°C.

Four column hydraulic press