The oil suction filter is installed at the oil pump suction port to protect the oil pump and other hydraulic components to avoid inhaling contaminated impurities, effectively control the pollution of the hydraulic system, and adjust the cleanliness of the hydraulic system.
The oil suction filter can be directly installed on the side of the tank, the upper part or the bottom part. The suction cylinder body invades below the liquid level in the oil tank. The suction filter filter head is exposed outside the fuel tank, and is provided with a self-sealing valve, a bypass valve, and the filter element is blocked by the filter. The device does not allow the oil in the tank to flow out when the filter element is replaced and the filter element is cleaned.
However, in order to avoid cavitation in the pump, it is necessary to pay sufficient attention to the pressure loss, and generally use a 100---200 mesh thick metal mesh or a notched wire material. Therefore, it is not a filter that controls the dirt concentration of the system.
Performance indicators
1. Filtration accuracy
Filtration accuracy refers to the filter capacity of the filter for different sizes of particulate pollutants. It is usually evaluated by absolute filtration accuracy, filtration ratio and filtration efficiency. The filtration precision is divided into coarse (d≥0.1mm) and ordinary (d≥0.01mm). ), fine (d ≥ 0.005mm), and special fine (d ≥ 0.001mm) four levels.
2. Pressure drop characteristics
The filter in the hydraulic system is a liquid resistance to the oil, so a pressure drop is inevitable when the oil passes. Generally speaking, in the case of a certain filter element size and oil flow rate, the higher the filtration precision of the filter element, the larger the pressure drop, and the larger the effective filtration area of the filter element or the viscosity of the oil when the flow rate is constant. The smaller the pressure, the smaller the pressure drop.
The maximum pressure drop allowed by the filter element should be based on the principle that the filter element will not be structurally damaged. Generally, the initial pressure drop of filters for aviation and ships should not exceed 0.25 MPa; the pressure drop of mechanical filters is not more than 0.08 MPa to 0.15 MPa.
3. Nanoscale capacity
The problem of contaminants trapped by the filter before the pressure drop is greater than its specified limit is called the dirt holding capacity, expressed in terms of weight (g). The larger the nanoscale capacity of the filter, the longer its life, so it is an important indicator reflecting the life of the filter. The larger the effective filtration area of the filter, the greater the nanoscale capacity.