How do you conduct a helium leak test?

1: Evacuate the chamber that is to undergo the helium leakage test; 2: Install equipment for monitoring helium leakage, ensuring that it can communicate with the interior of the chamber; 3: Cover the chamber from the outside using a sealing material when evacuation is required; 4: Introduce helium into the chamber and adjust the sensitivity of the leakage detection device; 5: Evacuate the chamber, stay nearby, and listen carefully; 6: If no alarm is detected by the monitoring device within 40 minutes, the test is successful. Note: The monitoring device must be calibrated before installation.

1: Evacuate the chamber that is to undergo a helium leakage test; 2: Install the equipment for monitoring helium leakage, ensuring that it can communicate within the chamber; 3: Seal the chamber from the outside once evacuation is complete; 4: Introduce helium and adjust the sensitivity of the monitoring device; 5: Evacuate the chamber again and listen carefully; 6: If no alarm sounds occur within 40 minutes, the test is successful. Note: The monitoring device must be calibrated before installation. The parts marked in blue have been modified; the parts marked in red don’t seem to make sense in Chinese, and I think they are incorrect.

It seems there are specific experimental protocols and equipment; it was only carried out on-site last month

A helium leak detection machine is required, which comes in internal pressure and external pressure methods. Generally, for small containers, the internal pressure method is used: a certain pressure of helium is filled inside the device, and then an inspection is carried out from the outside using a suction gun.

Helium detection is briefly described in Section 18.9.5 of the book \"Training Manual for Pressure Vessel Design Engineers\" written by Senior Li Shiyu.

I haven’t actually dealt with it yet; I’m just coming in to take a look. I have indeed seen the helium testing for valves

Simply put: 1. Evacuate the vacuum, 2. Replace with nitrogen, 3. Fill with a certain percentage of helium. 4. Hold pressure 5. Detect leaks with a helium leak detector (the sensitivity should be adjusted in advance) Last edited by nimoo on 2009-2-11 14:41]

As a supplementary note: although helium leak detection is very sensitive, it is difficult to identify the exact location of the leak; one can only gradually narrow down the possible area where the leak might occur. It is much easier to operate compared to ammonia leak detection; the leak location can be easily identified, and it offers significant advantages in terms of cost.

First, here is a direct translation of the original text: 1: Vacuum the Chamber which required Helium leakage test; The vacuum chamber must undergo a helium leak detection test. 2: The equipment for monitoring helium leakage shall be installed, and it must be able to communicate with the interior of the chamber; When installing the helium leak detector, its probes should be able to reach inside the vacuum chamber. 3: Cover the Chamber with a seal material from outside when the vaccum in the requirement is achieved; Once the desired level of vacuum has been reached, use sealing material from the outside to seal all areas of the vacuum chamber that might be prone to leaks. 4: Feed the Helium and adjust the leakage deadline of the monitor; Supply helium gas and adjust the minimum sensitivity of the leak detector. 5: Vacuum the chamber, stand nearby and listen; Check the level of vacuum and the integrity of the seals, while also listening for any noises. 6: If no alarm is issued by the monitor within 40 minutes, the test is successful. If no alarm occurs after 40 minutes, the test passes. Note: The monitor shall be calibrated before installation. Note: It is necessary to calibrate the leak detector before using it. In fact, everything is already explained quite clearly; I assume this is part of an installation or maintenance manual provided by a foreign party, likely related to the vacuum level testing requirements for turbine condensers. What confuses you now is the lack of a helium leak detector; otherwise, it would be quite straightforward. It can be purchased domestically or borrowed from the thermal testing laboratory; many alternatives are available, such as measuring the rate of vacuum drop or the maximum allowable vacuum level. The method remains the same even if it is not a condenser. The testing method is merely a means; what matters is identifying gaps and ensuring that the indicators meet the standards

Helium leak detection must be the most sensitive method for detecting leaks. I know that helium leak detection is used to inspect the tubes and tube sheets of steam generators in nuclear power plants (which function as U-shaped tube heat exchangers). It’s a pity I wasn’t there at the time and didn’t see it.