When choosing a filter, you need to consider factors such as filter performance, material quality, water flow, brand and after-sales service. These considerations not only affect the performance of the filter, but also determine the stable operation and service life of the entire system. Here are some specific considerations:
1. Filter performance
(1) Filtration accuracy
Filter accuracy is a key indicator of filter performance, which refers to the smallest particle diameter that the filter can intercept, usually in microns (μm). Different systems have different requirements for filtration accuracy, for example, the servo system generally recommends a filtration accuracy of 5μm, while the ordinary proportional system is between 9 and 10 levels, and the filtration accuracy is 10 to 20μm.
(2) Retention rate
The retention rate indicates the filter's ability to intercept impurities, and an efficient filter should have an excellent retention rate. The accuracy of the filter screen, the uniformity of the aperture and the packaging technology of the filter element will affect the retention rate.
(3) contaminant capacity
Contaminant capacity refers to the weight of contaminants that the filter element can hold before reaching the limit pressure difference. The selection of filter element with large capacity can reduce the replacement frequency and improve the stability of the system.
2. Material quality
(1) Filter material
Common filter materials include paper, metal mesh, glass fiber and so on. Paper filters are usually disposable, while metal mesh filters can be cleaned and reused, but disposable filters are easier to maintain cleanliness.
(2) Pressure and corrosion resistance
The material of the filter needs to be able to withstand the highest working pressure and corrosive environment in the system, such as 316 stainless steel with excellent corrosion resistance.
3. Water flow
(1) Traffic demand
The filter should have sufficient through-flow capacity to handle the system flow without creating excessive pressure drops. The filtration capacity of the oil suction filter should be more than twice the pump flow rate to prevent affecting the oil absorption performance of the pump.
(2) Pressure drop
The low pressure drop design can reduce the energy loss, specifically, the assembly pressure drop of the pressure oil filter should be ≤1bar, the return oil filter should be ≤0.5bar, and the oil suction filter should be ≤0.05bar.
4. Brand service
(1) Brand selection
Try to choose professional big brands, which are more guaranteed in quality control and after-sales service. Well-known brands such as Midea, Haier, etc., provide a three-year warranty, quality and price are closer to the people.
(2) Replacement and maintenance
Filters should be designed to facilitate routine maintenance and cartridge replacement without the need for complex tools.
5. Installation position
Filters at different locations have different performance requirements. For example, the oil suction filter needs to choose a model with strong circulation capacity to prevent the cavitation phenomenon; Pipeline filters pay attention to filtration accuracy and pressure resistance; The oil return filter needs to adapt to large oil return flow and low pressure requirements.
6. Working conditions
(1) Working environment
Select the appropriate type and precision filter according to the working pressure of the hydraulic system, oil viscosity, working environment, etc. For example, in precision hydraulic systems, high-precision filters should be selected to ensure oil cleanliness.