Barometers for different purposes have different ranges:

1. Barometers for different purposes have different ranges, some are only used to measure lower pressures, while others are measured in Psi or Bar units. We choose the appropriate one to use, just like we don't know how to measure height with a pencil ruler.

For example, a pressure gauge for scuba diving with Bar as the unit, generally speaking, the range of the pressure gauge can reach 300 Bar or more. Each scale interval is 10 Bar. The area between 0-50 Bar is particularly marked in red, which tells us: 'There's not much gas left.'.

2. It is particularly noteworthy to follow the rules of safe diving. If the remaining gas reaches the agreed warning line, notify the diving guide immediately and enter the water lifting procedure. This warning line is usually 50 bar, and in some deep diving situations, it is agreed to be 70 bar.

For example, in the deep diving of the AOW course, starting from half of the maximum depth, perform a deep stop and then slowly rise to make a safe stop. Can adding a deep stop during deep diving further reduce the risk of decompression sickness? Does diving no longer feel so tiring? 》）.

After informing the guide or coach that your remaining energy has reached the alert position, they will start arranging the ascent procedure without being overly nervous and worrying about running out of energy.

3. After being exposed to light, the dial or scale of the pressure gauge will emit fluorescence, and reading is not a problem even in dark environments. When diving at night, do not foolishly use a flashlight to look at the gauge. Instead, cover the dial with a flashlight and shine it for a while to make it fluorescent, and then it can be easily read.

4. Generally speaking, the pressure at which a gas cylinder is filled with gas is referenced to 200Bar. The maximum working pressure of Yoke interface valves is 230 bar, while some DIN interfaces have a maximum working pressure of 300 bar. Sometimes when the gas cylinder is just filled with gas, or after exposure to sunlight, the pressure inside the cylinder will increase, and the pressure gauge reading may reach as high as 230 Bar. After entering the water and the temperature of the bottle decreases, the pressure will naturally return to normal.

The above is the content explained by Shanghai Fengyun Meteorological to you. Do you all understand? I hope it is helpful to everyone. If you have any further questions, feel free to consult us online and we will answer them one by one.