Panasonic has a new weapon in its recycling arsenal for dealing with cathode ray tubes from old televisions: a powerful laser that can quickly weaken the thick glass and enable a three-fold increase in processing speed.
The glass cathode-ray tubes used in older televisions are typically made with different types of glass in the screen at the front and in the funnel at the back. For efficient recycling it is therefore necessary to cut them into two pieces, but this isn't like breaking a sheet of glass: The front and side walls of CRTs are typically a centimeter or more thick so cutting can be a tough job.
Until now Panasonic used a hot wire around the edge of the tube to weaken the glass so the screen could be split in two, said Kazuyuki Tomita, president of the Panasonic Eco Technology Center. PETEC sits among paddy fields in Kato, a rural town in western Japan, and handles recycling of TVs, refrigerators, air conditioners and washing machines from across the region.
At the recycling center the hot wire method allowed 24 CRTs to be processed every hour. Increasing this was a challenge because the wire still required a certain amount of time to get up to the correct temperature and heat the glass enough that it could be broken.
So Panasonic turned to a laser.
Using the new system, which Panasonic demonstrated to reporters for the first time on Thursday, the CRT is rotated so that the powerful laser runs across all four sides of the tube, creating a stress crack all around the screen. Once done all that's required is a sharp tap with a chisel and the tube is split into two pieces.
The new method has enabled a single operator to handle up to 72 CRTs per hour -- three times the rate using the hot wire. There are other advantages too: A computer system can adjust the laser so CRTs between 14 inches and 36 inches across can be handled by the new system, up from only five sizes using the hot wire, and the cut is cleaner, said Tomita.
The time-saving technology is being introduced as the expected volume of old CRT-based sets coming in for recycling is about to double. After rising from a little over 200,000 sets in 2005 to just under 300,000 sets last year, Panasonic expects as many as 650,000 sets to pass through PETEC in 2011 as the transition to digital TV continues. Japan will end analog TV broadcasting in July 2011 and most consumers are expected to junk old TV sets in favor of flat-screen digital models in the next couple of years.
Japan began requiring recycling of certain consumer and home electronics items in 2001 and recently expanded it to include flat-panel TVs and clothes dryers. The PETEC plant in Kato is already handling a small volume of flat panel sets and that is expected to continue to grow as early-generation models begin to reach the end of their life.