Patent schmatent. Those in-use covers were unknown in the field back in the days of Disco music.
There may be another cost-effective way to work valve control, if battery technology improves, along with solar power tech. Since conventional valve solenoids have some ability to work on continuous DC, a battery-powered solar-recharged control system might become the norm.
Last edited by Wet_Boots; 06-07-2014 at 11:42 AM.