Dishwasher with sensor unit for determining rotation of a spray arm
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Solution Overview
Problem
Existing dishwashers with radar or infrared sensors face operational reliability issues due to complex and expensive systems, and interference from water reflections, which affect the accurate detection of spray arm movement.
Innovation Solution
Incorporating guide elements to direct water away from infrared light beams and using an infrared sensor unit within a dosing device to monitor spray arm movement, with a focus on reliable detection through periodic signal analysis and interference filtering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guide elements are added to direct water away from the infrared beam path, then detection reliability is improved, but device complexity increases
Solution Approach 1:
The guide elements are integrated into the existing housing structure of the dishwasher, merging the water guidance function with the housing design. This eliminates the need for separate, additional components while still achieving the goal of directing water away from the infrared beam path, thus improving detection reliability without significantly increasing device complexity.
Solution Approach 2:
The guide elements act as an intermediary structure between the water flow and the infrared sensor unit. They redirect water flow away from the beam path before water can reach the sensor area, preventing interference signals while maintaining a relatively simple overall design.
2Reliability
If infrared sensors are used to detect spray arm movement, then operational reliability is improved, but cost increases
Solution Approach 1:
The infrared sensor unit is integrated into the dosing device, which already exists in the dishwasher for dispensing cleaning agents. This multi-functional approach allows the dosing device to serve both its original purpose and the new function of housing the spray arm rotation detection sensor, thereby reducing overall system cost while improving operational reliability.
Solution Approach 2:
The dosing device housing already provides protection and mounting infrastructure that can be utilized by the infrared sensor unit. By leveraging the existing structure and components of the dosing device, the patent avoids the need for separate sensor housings and mounting mechanisms, reducing manufacturing costs while maintaining reliable detection functionality.
3Ease of operation
If water is allowed to run down freely in the working space, then ease of operation is improved, but measurement precision deteriorates due to reflections
Solution Approach 1:
The guide elements are strategically positioned only in the critical areas where water flow would intersect with the infrared beam path. This localized approach modifies water flow behavior only where necessary to prevent reflections, while leaving the rest of the working space unchanged for ease of operation. The solution achieves measurement precision improvement without compromising overall operational ease.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures reliable and trouble-free detection of spray arm rotation, even under challenging conditions, with reduced complexity and cost, and the ability to monitor program sequences and detect malfunctions.
Implementation Method 1
The functional principle of the sensor unit is based on infrared light being emitted by an infrared transmitter, reflected in the work area and then detected again by an infrared receiver.
Implementation Method 2
an infrared beam can be reflected to the receiver via a stationary reflector in the working area of the machine, with changes in the IR beam, e.g. in intensity, being detected that are caused by a rotating spray arm, a component attached to the spray arm or by a jet of water or suds from the spray arm.
Data Source
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AI summary
A dishwasher with a working space, with at least one spray arm rotatably arranged in the working space and with a dosing device for supplying and dosing a substance, such as detergent, rinse aid, etc. into the working space, which as an insert part with a housing for insertion into a recess of a inner wall of the working space, for example in the door of the working space, and with a sensor unit for detecting a spray arm movement in the working space of the dishwasher, which is at least partially arranged in a housing of the dosing device, the sensor unit 11 having at least one infrared transmitter 12 and/or an infrared receiver 13 comprises.