A few minor issues with airtightness
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1. How to make negative-pressure containers and pipelines airtight and how to detect leaks? 2. Do steam pipes and high-temperature pipes need to be inspected for leaks as they gradually heat up, and how are leaks detected?
1: After the negative-pressure container and pipes are installed in place, a negative pressure of 120% of the operating pressure is applied, and the system is sealed. The changes in vacuum level can be observed directly using a vacuum gauge. It is generally specified that a loss of vacuum level of less than 10% within two hours is considered acceptable; if this criterion is not met, a leak detector is used to identify leaks. 2: Pressure testing is carried out on steam pipes and high-temperature pipes before operation; during the gradual heating process, manual inspections are conducted, and leak detectors are used to check for leaks
Regarding negative-pressure pipelines and containers, it is recommended to check the design documents; generally, they should have a certain capacity to withstand positive pressure. Perform positive pressure airtightness testing within this range; once no leaks are detected, conduct negative pressure testing as a verification. Because using negative pressure for airtightness makes it impossible to locate the leak point. For steam pipes and high-temperature pipes, leak checks are generally carried out during the heating process. However, \"thermal tightening\" is also necessary: after reaching a certain temperature, heating is stopped, and all the connection bolts are thoroughly inspected and tightened one by one to prevent leaks.