JB/T 11880.3-2014Diesel Engines - Selective Catalytic Reduction (SCR) Systems - Part 3: Urea Solution Line (English PDF)

6.1 Specimen preparation

The specimen status of the plastic parts shall be conditioned according to the provisions of GB/T 2918.

6.2 Appearance inspection

Observe it with naked eyes. Take a specimen with a length of 100 mm on the inner surface of the pipe and use a cutting tool to cut it along the axial direction. Check whether there is defect.

6.3 Inspection of dimensional tolerance

Product's dimensional tolerance requirements shall be implemented in accordance with GB/T 9575.

6.4 Burst pressure test

6.4.1 Room temperature burst pressure test

It is performed according to the provisions of GB/T 5563.

6.4.2 High temperature burst pressure test

After keeping at 100 °C for 0.5 h and 1 h, it shall be implemented in accordance with GB/T 5563.

6.5 Negative pressure deformation test

6.5.1 Specimen

There are five pipeline assemblies with a length of 300 mm between the pipe fittings.

6.5.2 Test process

At room temperature, apply a pressure of -0.05 MPa to the pipeline; keep it for 10 minutes; check for deformation.

After the test is completed, a ball with a diameter of 80% of the inner diameter

6.10 Flame retardancy test

Take five tubes with a length of about 125 mm as specimens.

Carry out the test according to the steps specified in test method A in GB/T 2408-2008.

6.11 Flow restriction test

6.11.1 Specimen

For a urea tube of a given diameter, cut three specimens as required. The length of the tube is calculated according to formula (1).

Where: L - The length of the tube, in millimeters (mm); Rmin - The minimum bend radius, in millimeters (mm).

6.11.2 Test process

Place the specimen on the test fixture as shown in Figure 1. When the tube is installed, it shall bend in the same horizontal plane and be in a free bending state. Keep the position of the tube and the test fixture unchanged at a room temperature of 23 °C ± 2 °C. Then put the steel ball into one end of the urea line, to check whether the steel ball can freely pass through the other end of the urea tube.

The diameter of the steel ball shall be calculated according to formula (2).

Where:

D - The diameter of the steel ball, in millimeters (mm);

ID - The minimum inner diameter of the inner tube, in millimeters (mm).

6.15 Heating performance test

6.15.1 Specimen

Take three pipeline assembly samples with a length of 1000 mm. Use 8 times the outer diameter of the tube as the bend radius to make it in U-shape.

6.15.2 Test equipment

A system device that can control heating and a thermostat that can control temperature.

6.15.3 Thawing test

The test process is as follows:

a) Put the pipeline assembly sample with the embedded temperature measuring device in the thermostat; connect it with the heating system; lead in 32.5% urea solution; set the required test temperature; start the thermostat;

b) When the measured temperature of the temperature measurement device reaches the set test temperature, start the heating controller, until the temperature of each temperature measurement point reaches 5 °C. Record the required time.

6.15.4 Heating cycle test

The test process is as follows:

a) Put the sample of the pipeline assembly embedded with the temperature measuring device into the thermostat; connect it with the heating system; lead in 32.5% urea solution; set the required test temperature; start the thermostat;

b) When the measured temperature of the temperature measurement device reaches the set temperature, start the heating controller; take 48 h as a cycle (the heating time is 24 h and the time without heating is 24 h); perform 20 cycles continuously;

c) After the test is completed, check the appearance of the pipeline; carry out the room temperature burst pressure test according to the requirements specified in 6.4.1. […]