Application of high-purity helium leak detector in boiler leak detection

Helium, high-purity helium

Buy high-purity helium and find Wuhan Yisi Tuopu Technology Co., Ltd. Click on the online inquiry or call our hotline at+86 189 8614 9031.

A boiler is an energy conversion device that discharges chemical and electrical energy from fuel into the boiler, while the boiler emits steam, high-temperature water, or organic heat carriers with a certain amount of thermal energy. The steam boiler that produces steam is called a steam boiler, usually abbreviated as a boiler, and is mainly used in fossil fuel power plants, ships, locomotives, and industrial and mining enterprises. Steam boilers often experience water leakage during operation. To solve this leakage problem, helium mass spectrometer leak detector has great advantages in boiler leakage detection. The data shows that if there are non condensable gases such as air in the boiler, even if they are very weak, they will have a very harmful effect on the condensation heat transfer process. For example, air with a mass content of 1% in water vapor can reduce the surface heat transfer coefficient by 60%, with serious consequences! It can be seen that improving the durability of vacuum maintenance for such boilers through various means is an important aspect. Therefore, all condensing boilers are tested using helium mass spectrometer leak detectors to ensure long-term maintenance of the boiler vacuum level! The following is a case study of a boiler leak. In order to thoroughly identify the leak point, a Noyce helium mass spectrometer leak detector was used to detect the heating surface inside the boiler, with a focus on inspecting the rear heating system.

The specific work steps are:

1. Remove something from the insulation layer. Remove all insulation layers on the outlet pipeline of the high-temperature heater for inspection;  

2. Inject compressed air and high-purity helium into the heating system. Isolate appropriate system valves and blow the pipeline with nitrogen to inject compressed air and high-purity helium into the reheating system;  

3. Detect leakage points. The helium mass spectrometer leak detector is used for detection and has the characteristics of fast speed, high reliability, high sensitivity, and easy operation. When the pressure of the post heating system reaches 0.3 MPa, start the helium mass spectrometer leak detector and insert the connecting pipe of the leak detector into the boiler. One person is holding a detector to inspect each heating system pipeline, while the other person is responsible for observing the readings on the leak detector screen. If you approach a specific tube, you will notice a significant change in the reading of the helium mass spectrometer leak detector. Immediately remove the insulation layer at this point, and as you approach the leakage point, you will notice a significant size jump on the leakage rate indicator. When approaching the weld seam, the fingers clearly feel a slight airflow, indicating that there is indeed a leakage phenomenon.  

4. Analysis of Leakage Causes:

(1) Improper initial welding process. In the original welding process, due to the low current, the filler material of the welding wire cannot fully fuse with the welding material, resulting in incomplete or incomplete welding, which is the main reason for congenital microcracks. If the energy of the weld seam is too high, the welding speed is too slow, the weld seam and heat affected zone become overheated, resulting in coarse martensitic structure and greatly reducing the comprehensive property of the weld seam.  

(2) Heat treatment after welding. Failure to perform timely heat treatment or improper heat treatment process after welding can affect the performance of the welded joint. Welding joints with poor performance may fracture in a short period of time under thermal stress.