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FLUID FLOW METER Disclosure Number: IPCOM000193170D
Publication Date: 2010-Feb-12
Document File: 3 page(s) / 17K

Publishing Venue

The Prior Art Database


A system is provided that uses thermal flow meter techniques to detect the flow rate of water flowing through a water and ice dispenser. The system includes a resistance heater and four thermocouples mounted directly to the water dispenser tube. The resistance heater continuously provides heat to the water flowing through the dispenser tube. As the water flows past, heat is transferred from the heater to the water and an upstream and a downstream thermocouple are provided at two positions on the heater to measure the change in temperature across the heater. A signal based on the temperature difference can then be used to determine the water flow rate.

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The present invention relates generally to home appliances, and more particularly to refrigerator water and ice dispensers. More specifically, this invention relates to an improved fluid flow meter for a refrigerator water and ice dispenser.

Appliances, such as refrigerators, generally include water and ice dispenser assemblies. Known refrigerators include a housing defining a cabinet which is separated into a fresh food storage compartment and a freezer compartment, with a fresh food storage door and a freezer door rotatably hinged to an edge of the housing to provide access to the fresh food storage compartment and freezer compartment. The refrigerator also includes an icemaker received within the freezer compartment to produce ice pieces, a through-the-door dispenser configured to deliver the ice pieces outside the cabinet for a user's access, and a water supply arranged in communication with the icemaker to supply water therein.

Some refrigerator water and ice dispensers known in the art are equipped with sensors that serve as fluid flow meters that detect the rate that water flows through the water and ice dispenser. These sensors are operatively connected to a controller that receives a signal from the sensor indicating the quantity of water passing through the flow meter. Based on the signal, the controller may control a means, such as a valve, for increasing or decreasing the quantity of water passing through the flow meter. The controller may be coupled to a memory element that provides preset flow rates for the controller to maintain within the dispenser. The controller may also be coupled to user interface controls that allow the consumer to dictate the quantity of water or the fluid flow rate within the dispenser.

Usually, the flow meter of the dispenser includes a rotating element, approximately half of which protrudes into the flow stream. The flow meter commonly includes a magnet mounted to the rotating element, and a circuit with a reed switch placed relative to the rotating element such that every time a magnet passes close to the reed switch, a circuit is completed and a pulse is generated. A programmable logic controller (PLC) with a high-speed counter is utilized with the reed switch such that an exact amount of water passing through the flow meter can be calculated.

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Although the fluid flow meters known in the art are considered to be effective for detecting the rate that water is flowing through the water and ice dispenser, there are disadvantages associated with the design. First, the rotating elements are moveable parts that tend to wear over time and require replacement. Also, the moving parts are placed in the flow and may contaminate the water moving past the meter. Additionally, the cost of the flow meters known in the art is increased by the fact that they contain several elements as described above.

As a result, there exist...