- Conditions and preparations for craft pipe test pressure
I.1. The pipeline system is completed and compliant with the design requirements and regulations.
I.2. The branch, the hanger and the pipe rack are finished, and the ray flaw detection has completely reached the design specifications, and the part of the test, weld and other should be tested is not painted and incubated.
I.3. The test pressure gauge has been verified, the accuracy is set to 1.5, and the full scale value of the table should be 1.5 to 2 times the maximum pressure measured.
I.4. Before the test, the test system, equipment and attachments will not be involved in the test system, and the position of the blind board is used to apply the white lacquer lacquered mark and record.
I.5. The test water should be used with clean water, and the chloride ion content in the water must not exceed 25 × 10-6 (25 ppm).
I.6. The temporary pipeline for the test is reinforced, and the safety and reliability should be checked.
I.7. Check if all valves on the pipe are on the open state, whether the spacers are added, and the retracting valve core is to be removed, and after the purge can be reset.
2. Process pipeline test
2.1.Pipe test pressure is 1.5 times the design pressure.
2.2. When the pipeline and equipment are tested as a system, the test pressure of the pipe is equal to or less than the test pressure of the device, and the test pressure of the device is not less than 1.15 times that of the pipe design pressure, and can be tested according to the test pressure of the equipment.
2.3.When the system is injected, the air should be exhausted, the air discharge point should be the highest point of the pipeline, and add a exhaust valve.
2.4. For pipelines with larger differences, the static pressure of the test medium should be measured in the test pressure. The test pressure of the liquid pipe should be subject to the pressure on the highest point, but the lowest point pressure must not exceed the tube components.
2.5. When the pressure is pressed, the boost should be slow, and after the test pressure is reached, it is regulated for 10 min, and there is no deformation without leakage. The test pressure drops to the design pressure, stops 30 minutes, and the pressure does not fall, no leakage is qualified .
2.6. After the test, the blind plate should be removed in time, and the water is placed, and the negative pressure should be prevented when drained, and it should not drain the water. When the leak is found during the test, it should not be processed, after eliminating the defect, it should be re-examined.
2.7. The leakage test was performed after the pressure test was passed, and the test medium used compressed air.
2.8. Leakage test pressure is designed to design pressure, leak test should focus on checking the filler, flange or threaded joints, vent the valve, exhaust valve, drainage valve, etc., with the foaming agent inspection without leakage.
3. craft pipe purge and cleaning
3.1. Process technology requirements
3.1.1. Process pipeline should be segmented and cleaning (referred to as purging).
3.1.2. The blowing method is determined according to the requirements of the use of the pipeline, the dirty procedure of the surface of the working medium and the inner pipe is determined, and the hair drying sequence is generally carried out in accordance with the supervisor, branch pipe, and discharge tube.
3.1.3. Before blowing, the instrument within the system should be protected and remove the orifice plate, the filter adjustment valve and the retracted valve body, etc., properly, and the like.
3.1.4. When purging, the dirt in the pipe should not enter the equipment, and the dirt blown out of the device shall not enter the pipe, the valve flange is added.
3.1.5. Pipe purging should have sufficient flow, and the purge pressure must not exceed the design pressure, and the flow rate is generally not less than 20 m / s. When purging, apply a wood hammer to beat the tube, and focus on the weld and the bottom of the pipe, but must not damage the pipe .
3.1.6. Pipe branch should be considered before blowing, and the rigging of the hanger should be reinforced when necessary.
3.2. Pipe purification, cleaning method
3.2.1. Water rinsing: Working medium is the pipeline of the water system. Water rinsing may reach the maximum flow rate or not less than 1.5 m / s in the tube. It is qualified for export water and transparency with the entrance. After the pipe is rinsed, the water should be exhausted in time.
3.2.2. Air purging: Working medium is gradually purged with compressed air segments for gas pipelines. If you meet the valve, you must remove the front flange to the docking board, and then reset it after the pipe is blown. The pressure must not exceed the container and pipe design pressure, and the flow rate should not be less than 20 m / s. During the air purge, when the exhaust gas is not smoking, the exhaust port is placed in the exhaust port to test the lacquered wooden target, and there is no rust, dust, moisture, and other debris on the target plate in 5 min.
3.2.3. Steam purge: The working medium is purged with steam in the steam pipe. Steam is purged before the warm tube should be slow, then naturally cool down to ambient temperature, then lift the warm tube, carry out the second purge, so repetition is generally not less than three times. The exhaust gas in the vapor purge is tilted upwards, and the mark is eye-catching. The exhaust pipe diameter should not be less than the diameter of the purge tube. Qualified standard: Double replacement targets for two consecutive times, such as the spots visible to the naked eye on the target plate size below φ 0.6mm, the depth of depth is 1 / cm2; the purge time is 15 minutes (ie two In the case of a pass, it is passed.
Post time: Nov-25-2021