Apparatus for cleaning a heater

Abstract

An apparatus for cleaning tubing in an operating heater, in which the tubing has an inlet and an outlet. While the heater is in operation, a pig is run through the tubing from the inlet to the outlet and then returned to the inlet along return tubing, in parallel connection to the heater tubing. A combined pig launcher and receiver mounted parallel to the tubing, and controlled with three-way full port valves, is used to launch pigs into the tubing and remove them from the tubing. A boost pump is used to force pigs back from outlet to inlet.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:  
     
         1 . Apparatus for pigging an operating heater, the apparatus comprising: 
 heater tubing having inlet tubing and outlet tubing, the heater tubing having a single path between the inlet tubing and the outlet tubing;    return tubing connected to the inlet tubing at a first junction and to the outlet tubing at a second junction, the return tubing and heater tubing together forming a circuit;    pig launching and receiving equipment connected for launching of pigs into and removal of pigs from the circuit formed of heater tubing and return tubing;    a pig tripper on the circuit for detecting passage of a pig; and    an outlet valve on the circuit for controlling flow into the receiving equipment in response to the pig tripper.    
     
     
         2 . The apparatus of  claim 1  in which the pig launching and receiving equipment comprises: 
 a pig launcher mounted parallel to one of the heater tubing and the return tubing; and  
 a pig receiver mounted parallel to one of the heater tubing and the return tubing.  
 
     
     
         3 . The apparatus of  claim 2  in which a single combined pig launcher and receiver functions as the pig launcher and the pig receiver.  
     
     
         4 . The apparatus of  claim 1  further comprising: 
 a boost pump connected to the return tubing by a boost pump connection pipe.