GB/T 20079-2006Hydraulic fluid power - Filters - General specification (English PDF)

3.1 Filtration ratio

The ratio of the number of pollutant particles larger than a given size x (c) per unit volume of oil upstream and downstream of the filter, represented by beta x (c). That is. beta x(c)=Nu/Nd Where.

Nu - the number of particles larger than x microns contained in a unit volume of oil upstream of the filter.

Nd - the number of particles larger than x microns contained in the unit volume of oil downstream of the filter.

Note 1.beta x(c) represents the filter's ability to filter particles larger than size x.

Note 2. The subscript "(c)" in beta x(c) indicates that beta x is measured and calculated using an automatic particle counter calibrated in accordance with GB/T 18854.

Without this subscript, beta x is measured and calculated using a particle counter calibrated by other methods.

3.2 Filtration rating

The minimum particle size x(c) that the filter can effectively capture (when beta x(c) >= 100), measured in microns, expressed in µm.

3.3 Dirt capacity (retention capacity)

The total amount of pollutants retained by the filter element when the pressure drop reaches the specified limit pressure drop, measured in grams, expressed in g.

3.4

c) Pressure line filter. filter installed on the pressure line.

5.1 Basic technical parameters

5.1.1 Filtration rating

The filtration rating of the filter shall comply with the requirements of the product technical documents.

The filtration rating (µm (c)) should be selected from 3, 5, 10, 15, 20, 25, and 40.When the filtration rating is greater than 40 µm (c), it shall be determined by the manufacturer.

5.1.2 Rated flow

The filter rated flow (L/min) should be selected from the following grades. 16, 25, 40, 63, 100, 160, 250, 400, 630, 800, 1 000.

When the rated flow is greater than 1 000 L/min, it shall be determined by the manufacturer.

5.1.3 Nominal pressure

The nominal pressure of the pressure line filter shall be selected according to the provisions of GB/T 2346.

5.1.4 Dirt capacity

The dirt capacity of the filter at rated flow shall be specified in the product technical documentation.

5.1.5 Indicating pressure drop

For filters equipped with a transmitter, the indicating pressure drop shall be indicated in the product technical documentation.

5.1.6 Bypass valve

5.1.6.1 Bypass valve cracking pressure drop

For filters equipped with a bypass valve, the cracking pressure drop shall be indicated in the product technical documentation.

5.1.6.2 Bypass valve sealing performance

6.1 Filtration rating test

The filtration rating test shall be carried out in accordance with the provisions of GB/T 18853. The indicators shall comply with the requirements of 5.1.1.

6.2 Dirt capacity test

The dirt capacity test shall be carried out in accordance with the provisions of GB/T 18853. The indicators shall comply with the requirements of 5.1.4.

6.3 Indicating pressure drop test

The test device shall comply with the provisions of GB/T 17486. Install the indicator to be tested; use a special plug to replace the filter element; use the test fluid to slowly pressurize the filter inlet until the indicator works. At this time, the inlet pressure value shall comply with the requirements of 5.1.5.

6.4 Bypass valve cracking pressure drop test

6.4.1 The test device shall comply with the requirements of GB/T 17486. Install the bypass valve in a special test fixture; connect the bypass valve inlet to the test oil pump; connect the bypass valve outlet to the atmosphere; use the test oil pump to pressurize the bypass valve until the pressure reaches 80% of the cracking pressure drop specified in 5.1.6.1; maintain the pressure for 3 minutes. The leakage of the bypass valve shall comply with the requirements of Table 1.

6.4.2 Continue to increase the pressure according to the method in 6.4.1 until the pressure reaches the cracking pressure drop specified in 5.1.6.1. The leakage of the bypass valve shall comply with the requirements in Table 1.

6.5 Bypass valve closing pressure drop test

According to the test method in 6.4.2, after the bypass valve is opened, gradually reduce the pressure by 7 kPa each time until it reaches the pressure drop specified in 5.1.6.3.

At this time, the leakage of the bypass valve shall comply with the requirements of 80% cracking pressure drop in Table 1.

6.6 Bypass valve pressure drop flow test

The test device shall comply with the requirements of GB/T 17486. Replace the filter element with a special plug; start the oil pump; adjust the test flow; when the flow reaches the rated flow of the filter, measure the pressure drop of the bypass valve. Its performance shall comply with the requirements of 5.1.6.4.

6.7 Filter clean pressure drop test

The test shall be carried out in accordance with the provisions of GB/T 17486. Its performance shall comply with the requirements of 5.1.8.

6.8 Compatibility test

Immerse the filter in oil at 135 °C for 72 hours. After inspection, its performance shall comply with the requirements of 5.2.2.

6.9 Filter low-pressure sealing property test

Fill the filter cavity with test oil; block the filter outlet; pressurize the inlet to 15 kPa and maintain for 3 minutes. Its performance shall comply with the requirements of 5.3.1.

6.10 Filter high-pressure sealing property test

Pressurize the filter inlet according to the test method in 6.9 until it reaches 1.5 times the nominal pressure; maintain it for 2 minutes. Its performance shall comply with the requirements of 5.3.2.

6.11 Filter burst pressure test

Pressurize the filter inlet according to the test method in 6.9 until it reaches 3 times the nominal pressure; maintain it for 1 minute. Its performance shall comply with the requirements of 5.3.3.

6.12 Filter pressure flow characteristics test

The filter pressure flow characteristics test shall be carried out in accordance with the provisions of GB/T 17486.