Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities, and you.
Pressure on a Front-Loading Washing Machine Seal
Unlike a top load washing machine, a front-load washer has a door boot, a flexible bellows-like seal, to prevents leaks. So, how much pressure can it withstand? Too much detergent can produce an excessive amount of soap bubbles or suds. Without answering the question, it turns out that the better response is you don’t want to find out, so use less detergent and avoid the problem.
High efficiency (HE) washing machines, like front loaders, are designed to use less HE detergent specially formulated with suds suppressors to prevent the machine from over-sudsing. In some washers, when the use of too much soap is detected by either a pressure switch (or sensor) or by the motor control unit sensing a suds-lock condition (by analyzing the current draw on the drive motor), a SUD error code flashes. Usually, just letting the machine rest to allow the bubbles to dissolve is the recommended response for the user. However, the error can also be caused by an obstructed drain that can require a repairman to resolve. The solution remains: use less detergent and avoid the problem.
Source: Diego Cervo/Shutterstock
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Welcome to All Sensors “Put the Pressure on Us” blog. This blog brings out pressure sensor aspects in a variety of applications inspired by headlines, consumer and industry requirements, market research, government activities and you. In this blog we’ll be discussing the pressure in washing machines.
Sensing Pressure in Washing Machines
Initially, timing was used to estimate the amount of water for various washing machine cleaning cycles. Today, many manufacturers sense the pressure developed in an air dome that is referenced to the water level and provides a much more accurate measurement. The air pressure level is measured either by a pressure switch or a pressure sensor with air providing isolation from the long term effects of operating a diaphragm in direct contact with water and other contamination.
The pressure switch can close and/or open contacts to provide an input to other circuitry. In contrast, the pressure sensor can provide either an analog or digital output to the washing machine control unit. Since the pressure sensor’s output directly results in a power control function such activating a pump or motor, in some manufacturers products, the pressure sensor is mounted in a Power Control and Pressure Sensing Module. The water level in most washing machines is well below 2 feet (0.87 psi), so a pressure sensor that can measure 1 psi would work in this application.
Air pressure is sensed to measure water level in washing machines. Source: http://removeandreplace.com/wp-content/uploads/2013/12/washer-overfill.jpg
What do you think/Comments?
Do you have a pressure sensing question? Let me know and I’ll address it in an upcoming blog.
– Han Mai, Senior Marketing Specialist, All Sensors Corporation ([email protected])