Washing Machine Pump Backflow Detection and Counter-Pressure Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional laundry care appliances without a non-return valve experience backflow of washing liquid into the tub due to height differences, leading to re-wetting of laundry, which is undesirable.
Innovation Solution
A laundry care appliance equipped with a variable-speed pump and a controller that detects impeller rotation direction to activate the pump in a specific manner, generating counter-pressure to reduce backflow, and includes a power detection element to manage electrical power for effective backflow reduction without a non-return valve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a non-return valve is installed in the suction line or on the drain opening, then backflow of washing liquid is prevented, but device complexity increases and reliability decreases due to additional failure points
Solution Approach 1:
The invention extracts and eliminates the non-return valve from the system entirely. Instead of adding a valve component, the pump itself is used to actively prevent backflow by generating counter-pressure, thereby simplifying the device structure while maintaining the backflow prevention function.
Solution Approach 2:
The pump is given a dual function: it not only pumps washing liquid during the washing cycle but also acts as an active backflow prevention device by generating counter-pressure when needed. This eliminates the need for a separate non-return valve and reduces overall device complexity.
2Object-affected harmful factors
If a non-return valve is installed, then backflow is prevented, but reliability decreases due to additional failure points
Solution Approach 1:
By removing the non-return valve from the system, the invention eliminates the additional failure point that valves introduce. The backflow prevention function is transferred to the pump, which is a more reliable component with no moving parts in the flow path.
Solution Approach 2:
The pump serves itself by using its own operational capability to prevent backflow. The control unit monitors conditions and activates the pump to generate counter-pressure when backflow is detected, making the system self-regulating without requiring additional passive components.
3Object-affected harmful factors
If the pump is activated frequently to prevent backflow, then backflow reduction is effective, but energy consumption increases
Solution Approach 1:
The pump is activated periodically based on detected backflow conditions rather than continuously. The control unit monitors the system and activates the pump only when backflow is detected, thereby reducing energy consumption while maintaining effective backflow prevention.
Solution Approach 2:
The pump operates at different rotational speeds depending on the backflow condition. The control unit adjusts the pump's rotational speed parameter to match the required counter-pressure level, optimizing energy consumption while effectively preventing backflow.
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
The solution effectively prevents washing liquid from flowing back into the tub, reducing re-wetting and maintaining cleanliness, while also detecting low washing liquid levels to supply more liquid and alerting users.
Implementation Method 1
the pump has an impeller which is designed to rotate in a first direction of rotation and in a second direction of rotation opposite to the first direction of rotation
Implementation Method 2
the controller is configured to activate the pump during a second period of time following the first period of time in order to rotate the impeller in the second direction of rotation and to reduce the volume flow of the washing liquid flowing back
Implementation Method 3
the controller is designed to detect rotation of the impeller in the first direction of rotation during a first period of time when the pump is deactivated, in order to detect washing liquid flowing back in a reverse flow direction opposite to the pumping direction
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention relates to a laundry care appliance (100) with a tub (105) for receiving washing liquid, wherein the tub (105) has a drain opening (109), wherein the drain opening (109) is fluidly connected to a suction line (111), a variable-speed pump (113) for pumping washing liquid, wherein the pump (113) has a suction chamber (113-1) which is fluidly connected to the suction line (111), and wherein the pump (113) has a pressure chamber (113-2) which is fluidly connected to the suction chamber (113-1) and fluidly to a pump line (115, 115-1, 115-2), wherein the pump (113) has an impeller (113-3) which is configured to rotate in a first direction (114-1) and in a second direction opposite to the first direction (114-1). direction of rotation (114-2), and a control (119) for controlling the variable speed pump (113),wherein the control (119) is configured to activate the pump (113) during a pumping operation in order to rotate the impeller (113-3) in the second direction of rotation (114-2) and to pump washing liquid in a pumping direction (121) from the suction chamber (113-1) into the pressure chamber (113-2) and from the pressure chamber (113-2) into the pump line (115, 115-1, 115-2). The controller (119) is configured to detect, during a first time period with the pump (113) deactivated, rotation of the impeller (113-3) in the first direction of rotation (114-1) in order to detect washing liquid flowing back from the pump line (115, 115-1, 115-2) into the pressure chamber (113-2) and from the pressure chamber (113-2) into the suction chamber (113-1) in a reverse flow direction (123) opposite to the pump direction (121). The controller (119) is configured to activate the pump (113) during a second time period following the first.to rotate the impeller (113-3) in the second direction of rotation (114-2) and to reduce the volume flow of the backflowing washing liquid.