that round thing is called gas regulator,,,,,,,,,,pressure inside the main gas pipe is very high,,,,,,,,,this regulator reduces that pressure and supply the gas at the constant rate,,,,,,,,,,,the NG kit of generator also work in a similar way and both have similar inside mechanism,,,,,,,,,the only difference is that this gas regulator work on higher pressure and the NG kit of generator work on lower pressure,,,,,,,,,,,the regulator fitted on LPG cyliders also do the same work,,,,,,,,,,,,the CNG kit installed in our car also have similar working ,,,,,,,,,the only difference is that it is desighned to work at very very high pressure,,,,,,,,,,so high that the pressuse cant be droped in one phase,,,,,,so there are 3 chambers inside it and each fitted with diaphagrams,,,,,,,,,,,,pressure reduced in each chamber and then supplied to engine,,,,,,,,,,,the NG kit of generator has just one chamber inside it because it work on very low pressure,,,,,,,,but if we have to use that generator/NG kit on LPG then we add another regulator with cylinder which reduces the cylider pressure and then supply to gas kit,,,,,,,,,,,i havent touch that gas regulator of my home but i have set the pressure from it in one of my relatives home,,,,,,,,,,they were suffering from very low gas pressure ,,,,,they wont use genertor but low pressure were effecting there kitchen and water heater,,,,,,,,,
