What is the function of a siphon tube in a boiler?

The function of a siphon tube in a boiler is to protect gauge mechanisms from live steam. Siphon tubes are specifically designed to create a barrier and prevent direct exposure of the steam or hot water to the pressure gauge. This is important because high temperatures and pressures can cause damage to the gauge mechanism, leading to incorrect readings or malfunction.

When steam travels through the siphon, it cools down slightly, condensing to water within the tube. This cooler water forms a barrier between the high-temperature steam and the pressure gauge, allowing for accurate pressure readings without risking the integrity of the gauge itself. Consequently, the use of siphon tubes enhances the safety and reliability of boiler operations by ensuring that operators can accurately monitor pressure levels without the risk of equipment failure due to excessive heat.