METHOD OF TEMPORARY SHUTTING-OFF OF PIPE LINES Russian patent published in 1999 - IPC

FIELD: pipe line transport; temporary shutting-off of pipe lines filled with liquid, mainly with oil for conducting repair jobs. SUBSTANCE: method consists in introducing sealing plug into pipe line and pumping cooling agent through it at temperature of phase transition lying within range of solidification temperature of product being handled defined by higher energy of activation of viscous flow which is higher than limit of steel brittleness of pipe. Used as cooling agent is mixture of dry ice and aqueous solution of ethyl glycol by whose content temperature of phase transition is controlled. Liquefied gases are also used as cooling agent whose phase transition temperature is regulated by their saturation pressure. Liquefied gas is fed to sealing plug at surrounding temperature followed by its evaporation at required saturation pressure defining the evaporation temperature of cooling agent. High-pressure gas is used as cooling agent which is throttled in sealing plug. According to another version, sealing plug is filled with liquefied gas after introducing it into pipe line and temperature in sealing zone is regulated independently till complete evaporation of liquefied gas-cooling agent. To reduced time required for shutting off the pipe line, sealing plug is introduced into pipe line through existing branch pipe fitted with fully-opening gate. EFFECT: enhanced reliability of shutting-off pipe line. 1 dwg