Browse Prior Art Database

# Water Level Detection on Laundry Washers Using Capacitance Measuring While Also Using the Microprocessor to Monitor Flow Rate.

IP.com Disclosure Number: IPCOM000031230D
Publication Date: 2004-Sep-17
Document File: 5 page(s) / 38K

## Publishing Venue

The IP.com Prior Art Database

## Abstract

This invention uses physical capacitance difference between air and water in the clothes washer. This invention uses 3 plates mounted on the side of the plastic washer tub that when used with electronics can detect the water level. This is graphically represented in the diagram # 1 on the next page.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 74% of the total text.

Page 1 of 5

Subject: Patent Disclosure Letter: Water Level Detection on Laundry Washers

Using Capacitance Measuring While Also Using the Microprocessor to Monitor Flow Rate.

Date: October 16, 1998

Summary of Invention:

This invention uses physical capacitance difference between air and water in the clothes washer. This invention uses 3 plates mounted on the side of the plastic washer tub that when used with electronics can detect the water level. This is graphically represented in the diagram # 1 on the next page.

Page 2 of 5

Page 3 of 5

Detailed Description

The capacitance changes dramatically when water is between the two plates as compared to air. The electronics can make that capacitance into a switch to shut the water off. Once the water level is detected by the use of a switch, then the dielectric constant can be solved using the equation: C = (ε * A)/d

A is defined as the surface area of the plates when they are perpendicular to each other (ignoring fringe effects). d is the distance between the two pairs of plates. ε is the dielectric constant. The dielectric· constant of water is about 80 while the dielectric of air is 1. Since plate # 1 acts similar to a switch, then the dielectric of the solution can be calculated because the area of plate #2 is known.

Example (Includes Diagrams 2, 3, and 4):

Diagram #2 - Start Filling (No Water on Plate #1)