Hydrostatic test of seamless boiler tubes

Seamless Boiler Tubes are a type of steel tube manufactured by hot rolling or cold drawing without welds. They are a special type of boiler tube and belong to the category of seamless steel tubes, but there are strict specifications for the steel types used. They are specially used to transport high-temperature and high-pressure water, steam or other media in boiler equipment. Because of its overall structure without welded joints, it has higher pressure bearing capacity and safety, and is the core component of high-pressure boiler systems.

High-pressure seamless boiler tubes are subjected to high temperatures and pressures during use. They are exposed to high-temperature flue gas and water vapor, which can cause oxidation and corrosion. Therefore, these tubes must have excellent durable strength, anti-oxidation and corrosion properties, and stable structural integrity. High-pressure seamless boiler tubes are mainly used to manufacture superheater tubes, reheater tubes, gas guide tubes and main steam pipes for high-pressure and ultra-high-pressure boilers.

Hydrostatic test of seamless boiler tubes:

Pipeline hydrostatic test is a key inspection link that must be carried out after the installation of pressure pipelines. It aims to determine whether the pipeline system can withstand the designed working pressure, check whether there are leakage problems in the pipelines and their interfaces, and ensure the safe and stable operation of the pipeline system after it is put into use. It is widely used in many fields involving pipeline laying, such as construction, municipal administration, and industry.

The hydrostatic test of seamless boiler tubes is divided into two forms: working pressure test and overpressure test. The purpose of these tests is to test the strength and tightness of pressure-bearing parts. Usually, after the maintenance or replacement of pressure-bearing parts such as valves, furnace tubes, headers, or after small and medium-sized repairs of boilers, working pressure tests must be carried out. For newly installed boilers, overhauled boilers, and boilers with excessive replacement of heating surface tubes, an overpressure test of 1.25 times the working pressure is required.

Test preparation:

1. Prepare test equipment: pressure gauge, water tank, joints, nuts, etc.
2. Prepare test water: clean, clean tap water or distilled water should be used, and water containing impurities or foreign matter should not be used.
3. Clean the boiler pipeline: Before the test begins, the boiler pipeline should be cleaned to remove dirt and impurities in the pipe.

From the test preparation stage, it is necessary to ensure that the pipeline installation has been completed according to the design requirements, the connection parts are firm and reliable, and the inside of the pipeline is cleaned to prevent debris from affecting the test results. Temporary support should be set up reasonably to prevent the pipeline from being displaced due to pressure during the test. It is also necessary to install an exhaust valve at the highest point of the pipeline system and a drain valve at the lowest point, and prepare pressure measuring instruments with accuracy that meets the requirements, such as a pressure gauge.

Test steps:

1. Introduce the test water into the boiler pipeline and close all valves.
2. Use a pressure gauge to measure the initial pressure in the pipeline and record it.
3. Connect the water tank to the boiler pipeline through the connecting joint, so that the water in the water tank is slowly injected into the pipeline.
4. Observe the pressure in the pipeline while filling water until it is full.
5. Close the water inlet valve, wait for the pressure in the pipeline to stabilize, use the pressure gauge to measure the pressure in the pipeline again, and record it.
6. Remove the connecting joint and drain the test water.

Evaluation of test results:
The performance of the boiler tube is evaluated based on the initial test pressure, the pressure after water filling, and any leaks observed during the test.

1. Check for leaks: If leaks are found, repairs should be made immediately.
2. Verify that the pressure is normal: Make sure the pressure is within the acceptable range and meets the standards.
3. Determine the pass: If the boiler tube meets the standards, it is considered to have passed the test.

Safety measures:
Maintain stable pressure during the test to prevent sudden pressure fluctuations.
Avoid overfilling the water tank to prevent overloading and potential safety accidents.
Ensure workplace and equipment safety; avoid testing in hazardous areas or near hazardous facilities.

In short, the hydrostatic test of seamless boiler tubes is a critical process that must be performed accurately to ensure reliable and long-term operation of the equipment.

Read more: What are seamless boiler tubes and how are they made? or Carbon steel ERW boiler tube & air heater tube