Engineers from GE Consumer & Industrial combined technology from the medical device industry with a specially designed sensor to create an intelligent detergent dispensing system. The technology, built into the new GE Profile SmartDispense washers, automatically distributes detergent using information it gathers from each load. The system uses three independent tanks—two for detergent and one for fabric softener. Three peristaltic pumps deliver the calculated dosage into the cycle.
Jennifer Mintman, product general manager, says the peristaltic pumps are similar to those used in medical applications to deliver accurate doses of medication. “Also, the tubes used to transport the detergent and fabric softener from the storage tanks under the washer to the tub are made of a highly engineered material specifically designed to endure mechanical and chemical stress,” she adds.
Each storage tank has a sensor to detect the level of detergent remaining. When the sensor detects a low level, the washer will display a refill reminder to the user.
According to Mintman, sensing the presence of fluid in the storage tanks proved to be an engineering challenge. “Continuity sensors are typically used to detect the presence of a fluid and make a logical fit for our application,” she explains. “The basic concept is that the sensor places a very small voltage across two metal pins exposed to the inside of a fluid tank. If a fluid is present, a small amount of electricity will flow from one pin to the other through the fluid, which the sensor recognizes.”
The challenge, she says, is that some detergents and fabric softeners are fairly viscous and can fool a traditional continuity sensor by coating the sensor. Therefore, GE engineers spent a lot of time researching and testing the electrolytic properties of every brand of detergent and fabric softener. “A specialized continuity sensor was developed that can determine the difference between a sensor that is submerged and one that is coated, but not submerged with a fluid,” Mintman tells APPLIANCE.
In order to determine the correct dosage, the washing machine calculates the appropriate amount of detergent based on water hardness, fabric or cycle type, detected load size, and input from the user regarding the detergent concentration level. This meant GE engineers had to lean on the expertise of industry partners. “Collaboration with Proctor and Gamble helped GE understand what dosage levels were required based on these variables to accomplish a great wash performance,” Mintman says.