Patent ID: 7552740

Claim:
A method for handling an easily polymerizable substance, comprising: renewing a liquid comprising an easily polymerizable substance retained in a bypass line by opening and closing a shutoff valve provided in the bypass line intermittently while the liquid containing an easily polymerizable substance flows through a line provided with a flow control valve or flow meter, to provide some of the liquid comprising an easily polymerizable substance to the bypass line of the line provided with the flow control valve or the flow meter while the shutoff valve provided in the bypass line is open, wherein the time between intermittent opening and closing the shutoff valve provided in the bypass line is determined to provide a retention time of the easily polymerizable substance retained in by the bypass line to be less than a time where polymerization would lead to formation of polymer clogging the line, and the easily polymerizable substance is a polymerizable vinyl compound or a mixture of polymerizable vinyl compounds.