20 дюймов из углеродистой стали зажатый крышки канализационных люков

20 inch manhole cover

installed on the top of oil tanker. It is the internal inlet of loading, checking vapor recovery and tanker maintenance. It can protect the tanker from emergency.
Normally, the breathing valve is closed. However, when load unload oil external temperature changes, and the pressure of tanker will change such as air pressure and vacuum pressure. The breathing valve can automatically open at a certain air pressure and vacuum pressure to make the tank pressure in normal condition. If there is emergency like roll over situation, it will automatically close and it also can avoid the tanker explosion when in fires. As the emergency exhausting valve will automatically open when tank truck interior pressure increases to a certain range.

We are manufacturer for oil tanker truck parts and sprinkler pump more years in China ,our company has leading enterprise in this line which local in wenzhou city ,near wenzhou airport . Meanwhile , we had been attend in Canton Fair and Automechanika overseas exhibition every years . Meet ,welcome here for everybody .Thank you