Valve gaurds is different from flange spray shields, some time have same to the standwards flange spray shields
such as gata vavle ，they are made of three standwards flange spray shields.
most valve guards is one piece type shields ,some time vavle hand is center ,so need small center hole in vavle guards,
such as butterfly vavle ,ball valve ,some type valve hand is offset .such as ball offset hand vavle,some time center hole is big,because vavle with actuator,the guards needle through full actuator,so center hole is big.
Bonnet type is two standwards shields is flagne spray shields ,the other type is Orf tapered shields
