Wiper drive motor, 40 W, part 420010-02, for Hanovia medium-pressure ultraviolet disinfection systems built around the 38 mm quartz sleeve. The motor drives the wiper along the sleeve on the controller’s timed cycle. The quartz sleeve is the only optical path between the lamp and the water, so any film of scale or iron on its outer surface cuts the delivered UV dose. The wiper sweeps the sleeve on a timed cycle to keep transmission at the design figure. The 38 mm figure is the quartz sleeve diameter this drive is rated for; the range also uses a 47 mm sleeve, and wiper components are specified against the sleeve diameter. Reference number 2287-1011.