Selection of water filter cartridge

In the quality period of the new car, the substitute of the filter (filter element) should not be used. Even after the warranty period, the filter should be carefully selected. The performance of the diesel filter has a grade code according to the ISO standard. In addition to the performance test according to the SAE standard, the air filter element must be subjected to a bench test to meet the original intake resistance of the engine's rated intake air. Qualified oil filter must meet the original design of engine cylinder pressure, oil temperature, flow, viscosity and vehicle operating conditions, etc., and the comprehensive balance of core quality must be considered. The hydraulic oil filter element is marked on the manufacturer's product sample or nameplate as the nominal filtration accuracy, not the effective filtration accuracy. Only the beta value determined by the pass test can indicate the filtration capacity of the filter. The hydraulic oil filter element should also meet the requirements of pressure loss (the total pressure difference of the high-pressure filter is less than 0.1PMa, and the total pressure difference of the return oil filter is less than 0.05MPa) to optimize the flow rate and the life of the filter element.

　　 When selecting the filter (filter element), you can choose the original one, or you can choose the second brand. It should be noted that the selected filter element should be checked and accepted to check whether it meets the performance indicators it should have.

　　1, air filter

　　The selected air filter element must match the power, economy and performance of the original engine.

　　(1) Rated air intake

　　The air chlorine flow rate in the technical parameters of the filter element should be greater than the rated intake air volume of the equipped engine.

　　(2) Filter material

　　 There are requirements for the filter material thickness, tension resistance, original air intake resistance, filtration accuracy, etc. Imported diesel engine requires air filtration accuracy of 5μm, domestic diesel engine should also be less than 20μm. The filtering accuracy of effective filter paper is 2μm, ordinary imported filter paper is 30μm, while domestic filter paper is only 80μm.

　　(3) Filter element performance test

　　① Flow-resistance (pressure drop) test Measure the air flow pressure loss (flow-resistance or flow-pressure curve).

　　②The original filter efficiency test can calculate the dust collection efficiency of the filter element, and the dust reduction rate of the normal filter element should be more than 99%.

　　③Dust storage capacity test and cumulative efficiency test Excessive dust accumulation in the filter element causes blockage and increases air intake resistance. The air intake resistance when the engine power is reduced by 5% or the fuel consumption is increased by 5% is a limit value. When this value is reached, the filter element must be cleaned or replaced. During the test, the dust weight when the air intake resistance or pressure drop reaches 7-46kPa is the dust storage capacity of the filter element, and the filtration efficiency during this test is the cumulative efficiency.

　　④Original intake resistance test The intake resistance 9 rated pressure difference between the inlet and outlet when the air volume passes through the filter element) should not exceed 3.2kPa, and the power will drop and the engine will emit black smoke.

　　 Diesel filter

　　The diesel filter shall be tested as follows in accordance with the ISO4020 standard (road vehicles-fuel filter test method for automobile diesel engines).

　　(1) New filter cleanness test

　　 Determine whether the inside of the filter element is cleaned of dust and impurities remaining in production, storage and transportation.

　　(2) Bubble method test

　　 is used to confirm whether the filter element has pores larger than the filtration accuracy.

　　(3) Filtration efficiency and life test

　　 Filtration efficiency refers to the determination of the percentage of specific particles that are filtered out, and the filter life is expressed as the time when the plugging test pressure difference is greater than 0.07MPa.

　　(4) Water separation validity test

　　 Determine the percentage of water in the oil-water mixture separated by the oil filter.

　　(5) Filter element damage test

　　 Determine the rupture pressure of the filter element.

　　(6) Damage test of oil filter assembly

　　 Determine the ability of the assembly to withstand internal pressure.

　　(7) Pulsating pressure fatigue test

　　 Measure the mechanical strength of the oil filter assembly under pulsating pressure (simulating when the engine is started or stopped).

　　(8) Vibration fatigue test

　　 Determine the mechanical strength of the oil filter against vibration under normal use conditions.

　　3, oil filter

　　 Full-flow oil filter should be tested in accordance with ISO4548 standard.

　　(1) Pressure drop-flow characteristic test

　　 Use the oil of the specified viscosity to measure the pressure drop-flow curve of the oil filter assembly.

　　(2) Characteristic test of filter bypass element

　　 Measure the filter element pressure drop-bypass flow curve. When the pressure drop through the filter element is low, in order to limit the amount of unfiltered oil, when the bypass element is lower than the specified opening pressure drop, a small amount of oil leakage is allowed; and when the filter element is effectively blocked, it can be bypassed Pass the full flow without exceeding the specified pressure drop.

　　(3) High pressure drop and high temperature characteristic test

　　 The oil filter will experience a high pressure drop during operation (especially when the filter element is clogged). In addition, the filter element is also affected by the high temperature of the oil, and the ability of the filter element to withstand high pressure drops without being damaged should be tested under simulated high temperature conditions.

　　(4) Filter element life and filtration efficiency test

　　Using the particle counting method to determine the filter element is ordered to draw the relationship curve of pressure difference-test time or pressure difference-ash weight during the test, and the test time or pollutant weight when the design opening pressure of the bypass valve reaches 75% is used to indicate the life of the filter element.

　　(5) Cumulative efficiency test

　　 When using gravimetric analysis to determine the life of the filter element, it is evaluated by the test time when the end-point pressure difference is reached or the amount of pollutants captured.

　　(6) Hydraulic pulse fatigue test

　　 The oil filter is subject to the fluctuating pressure in the engine cooling state during use. During the test, use the specified pulsating oil pressure to cycle 1000 times to determine the pressure resistance of the oil filter housing, seal ring and filter element against high pressure fluctuations.

　　(7) Vibration fatigue test

After installing the machine stain filter assembly, add the resonance frequency and amplitude caused by the vibration surface of the engine or the installation structure, maintain the specified oil pressure, and circulate 10 million times to ensure that there is no small oil leakage or fatigue damage performance .

　　4, hydraulic oil filter element

　　(1) Filter accuracy

　　* First, determine the cleanliness level of the stains according to the needs of the hydraulic system, and then select the filter accuracy of the oil filter according to the cleanliness level according to the table. The hydraulic oil filter element commonly used in construction machinery has a nominal filtration degree of 10μm.

　　 Hydraulic oil cleanliness (ISO4406) Nominal filtration accuracy of filter element (μm) Application range

　　13/10 3 hydraulic servo valve

　　16/13 5 Hydraulic proportional valve

　　18/15 10 General hydraulic components (>10MPa)

　　19/16 20 General hydraulic components (<10MPa)

Since the nominal filtration accuracy cannot truly reflect the filtration capacity of the filter element, the diameter of the largest hard spherical particle that the filter can pass under the specified test conditions is often used as its effective filtration accuracy to directly reflect the initial stage of the new filter element. Filtering capacity.

The *main criterion for evaluating hydraulic oil filter elements is the β value measured according to ISO4527-1981E (multi-pass test), that is, the oil mixed with the standard test powder is circulated through the oil filter multiple times, and the oil inlet and outlet The ratio of the number of particles.

　　(2) Flow characteristics

　　The flow rate and pressure drop of the filter element through the oil are important parameters of the flow characteristics. The flow characteristics test should be carried out according to the ISO3968-91 standard to draw the flow-pressure drop characteristic curve. Under the rated oil supply pressure, the total pressure drop (the sum of the pressure drop of the filter housing and the pressure drop of the filter element) should generally be below 0.2MPa.

　　(3) Filter element strength

　　 The rupture-impact test shall be carried out according to the ISO2941-83 standard. The pressure difference that drops sharply when the filter element is damaged should be greater than the specified value.

　　(4) Flow fatigue characteristics

　　 The fatigue test of 100,000 cycles shall be carried out in accordance with the ISO3724-90 standard.

　　(5) Test for the response of hydraulic oil

　　 The pressure flow endurance test shall be carried out according to the ISO2943-83 standard to verify the compatibility of the filter material with the hydraulic oil.

Principles of bag filter types

Bag filters can be divided into stainless steel bag filters, plastic bag filters, multi-bag filters, top entry open mold bag filters and side entry stainless steel filters. The application principles are as follows:

　　Stainless steel bag filter has many advantages such as simple structure, reasonable structure, good sealing performance, strong circulation capacity, and easy operation. In particular, the probability of side leakage of the filter bag is small, the filter accuracy can be effectively filtered, and the filter bag can be replaced quickly.

The plastic bag filter is a relatively high filtration system made of PP (polypropylene) material. With the excellent chemical resistance of PP material, the X100 plastic filter can meet the filtration applications of many chemical acid-base liquids. The casing of this product has no joints, no dead ends, and effective specifications; it is a high-quality, effective, economical and excellent product.

　　Multi-bag filter is suitable for large flow liquid filtration. From 2 bags to 24 bags, the specifications are complete, the inlet and outlet diameters are 3-18', the maximum flow rate of a single machine: 90-1080 cubic meters/hour. It can provide a quick-opening design, and the filter bag is very convenient to replace. It can also be used for more use. When replacing the filter bag after a long time.

　　 Top entry open mold bag filter adopts SAM bag filter system composed of patent ring structure SAM filter bag and related accessories. SAM provides 2#, 1# and 4# standard single bag filters to meet the requirements of different customers. Provide filters made of 304 stainless steel and 316 stainless steel, and O-rings of various materials to meet the needs of different fluids and working temperatures.

　　 side-in stainless steel filter adopts side-in-bottom-out method. The filtered liquid medium is pressed or drawn into the filter barrel by the pressure in the pipeline, and the liquid medium to be filtered is supported by the stainless steel plate punching support filter basket.

How does the filter work?

Generally, the filter element of the filter is composed of fiber media, filter mesh, sponge and other materials. After the solid and liquid particles (drops) in the compressed air are intercepted by the filter material, they are condensed on the surface (inside and outside) of the filter element. The liquid droplets and impurities accumulated on the surface of the filter element are precipitated to the bottom of the filter by gravity and then discharged through an automatic drain or manually.