The present invention relates to systems using balls for cleaning the inside of tubing in condensers and other forms of heat-exchangers in general, and to apparatus for recirculating the balls within such systems in particular.
Systems for cleaning the inside of tubing using balls for preventing the build up of coatings or any other fouling inside the tubing as they travel the length thereof are known in the art.
Various attempts have been made to design and implement efficient apparatus for recirculating the balls from the downstream side of the tubing to the upstream side of the tubing for another pass therethrough. Some systems, for example U.S. Pat. Nos. 3,882,931 to Kumagai and 4,234,993 to Kintner, use continuously driven pumps for recirculating the balls. Such systems are not only expensive but also suffer from considerable downtime for maintenance and repair purposes.
Other systems, for example U.S. Pat. No. 4,865,121 to Ben-Dosa, use a mechanically actuated ejector for ejecting the balls back into the upstream side of the tubing. Such type of ejectors are highly susceptible to malfunctioning because of the tendency of the balls to get wedged between the ejector and a separator screen and therefore also require considerable downtime for maintenance and repair purposes.
There is thus a widely recognized need for, and it would be highly advantageous to have, a system for cleaning the inside of tubing which includes simple, inexpensive and effective apparatus for recirculating the balls therethrough.