摘要 |
A cleaning efficacy indicator system (20) includes a light source (50) and a light receiver (56). A light-transmitting optical indicator element (30) receives light from the source (50) and transmits the light to the receiver (56). The receiver (56) provides at an electrical output signal (82) which varies in accordance with light received from the light source (50). The light-transmitting optical indicator element (30) is purposefully soiled on its outer surface (48) with a soiling agent to inhibit or alter its light transmitting abilities. However, upon effective washing, the indicator element (30) is able to transmit an increased light intensity. The indicator element (30) is washed with a load of soiled articles. Either during washing operations or subsequently, the light transmission through the indicator element (30) is monitored using the light output signal (82) of the light receiver (56). A select change in light transmission is indicative of effective washing operations.
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