When we were kids, we assembled a lot of toys like plastic models. Some models have hundreds of parts.
However, a scuba regulator consists of at most 30 to 40 parts.
If you just organize the parts well and assemble it, it will be no different from a plastic model like this, but repairing a scuba regulator requires a lot of experience.
This is because the pressure parameters must be set well for the regulator to function properly and allow the diver to breathe comfortably.
The vacuum pressure inside the second stage regulator where the orifice separates from the low pressure sheet at the beginning of the inhalation, as mentioned in the breathing cycle in the previously posted topic, is called the cracking pressure.
Another thing is the intermediate pressure, which lowers the high pressure gas supplied from the air tank to a low pressure of around 9 bar before flowing to the second stage regulator.
These two pressure adjustments set the force with which the orifice presses the seat to the value suggested by the manufacturer.
Setting the intermediate pressure and how to set the cracking pressure are topics that will be covered next, but the intermediate pressure setting can be easily set to an accurate value by just making a few important checks. However, because cracking pressure measures a microscopic vacuum pressure of less than 500 Pascal, it is not as easy to set accurately as you might think.
Still, we’ve set the cracking pressure so far by sucking these micro-vacuums into our mouths.
The important point here is that even if a very small amount of leakage similar to cracking pressure occurs at the part connected for sucking into the mouth, it is not noticeable.
Since the suction force is adjusted through experience, the problem is that even if there is a slight leak, it is not recognized and the problem is to suction more to set the cracking pressure.
Some workers do this without even testing the vacuum pressure, but even if they do test the vacuum pressure first, they suction the second stage regulator with their mouth and check whether it maintains a vacuum by attaching it to the mouth. This will also be covered in the next topic, but the vacuum pressure tested by suctioning the second stage regulator with the mouth is a large force of about 16KPa. Therefore, minor leaks cannot be tested.
So we need a tool that can create a microvacuum and maintain it uniformly.
SRSD is a well-controlled micro-vacuum pump that always provides the same micro-vacuum. And under these conditions the cracking pressure can be set.