The invention of the first automatic washing machine in 1851 freed women from grueling, back-breaking labor. As the designs and models progressed, the task of laundering clothes became much more simple. Today, washers can be found in a variety of sizes, colors, and styles. While front load washers with a horizontal axis are making an inroad in sales in the United States, the vertical axis top load washer is still the market leader.
When cleaning clothes, it is the combination of the mechanical energy of agitating the fabric, the thermal energy of temperature of the water, and the chemical action of the detergent that performs the task. But how does a top load washer provide that agitation?
How Does a Top Load Washing Machine Work?
While design features and the number of cycles offered on washers vary from manufacturer to manufacturer and there are a variety of price ranges, the basic workings of the two types of top load washing machines in the United States are the same.
The two types of top-loading washers: Standard and High-efficiency
- Standard top load washing machines in the United States, Canada, and Australia use a center agitator with propeller-like paddles to move clothes through the water from the top of the washer tub to the bottom. The top-to-bottom agitation continues for the length of the wash cycle forcing water and detergent through the fabrics to loosen any soil. In Asia, top load washer washers use an impeller agitator without the center post.
- High-efficiency top load washers are much more like their front load washer cousins. They have a drum rotating around a horizontal axis like a front loader, but there is no front door. They have a liftable top load lid like a standard washer. These machines operate and spin just like a front-loader and use half the amount of water required for a standard washer. An advantage of a top load high-efficiency washer is it does not require the folding rubber bellows seal like a front load model that can trap moisture and soil and cause odors. The top load design has a pair of symmetrical bearings rather than a single bearing on one side, reducing wear and tear on the mechanical operation.
In both types of top-loaders, there are two components: the control system and the mechanical system. The control system consists of the control boards, load size selector (pressure switch), the water temperature selector, timer, and the lid/locking switch. The mechanical system is composed of the motor, transmission, clutch, inner and outer wash tubs, agitator, pumps, water valve, suspension system, and a belt or motor coupling.
For both types of top-loading machines, after the user selects the load size, water temperature, and type of cycle, the outer tub is filled with water. In a standard washer, the water fully covers the clothes and floats them in the basket (unless the washer basket has been overstuffed). The agitator then moves the water and the clothes to provide the friction necessary to loosen the soil. A high-efficiency washer uses much less water (about 40 percent less) and does not completely cover the clothes with water at first. The agitator in the bottom of the tub draws the clothes into the water during the washing cycle.
Typically, the motor that powers the gearbox drives the agitator to move or spin in one direction. The water pump motor also spins one way as it recirculates the detergent-laced water. That same pump motor switches direction to pump or remove the water during the spin cycle. Top load washers have actually become more mechanically simple as manufacturers have developed new designs. However, the electronic controls have become much more complex. No longer can single control parts be replaced. The entire electronic control panel must usually be replaced with one component fails.
Thanks to the vertical design, top load washers allow laundry product dispensers for detergent, bleach, and fabric softener to operate through gravity and centrifugal force. On a front loader, the dispensers must be opened by a solenoid valve. The vertical design also makes it much more simple to move water in and out of the washer than the action in a front loader. Because of gravity and drain location, top load washers do not typically hold water after a cycle is completed that can cause mold and mildew odors. Cleaning maintenance for a top load washer is quite simple.
Patrick, Bethanne Kelly., and John M. Thompson. An Uncommon History of Common Things. National Geographic, 2009
Nayak, Rajkishore, and Saminathan Ratnapandian. Care and Maintenance of Textile Products Including Apparel and Protective Clothing. CRC Press, 2018
Chen-Yu, Jessie H., and Joann Emmel. Comparisons of Fabric Care Performances between Conventional and High-Efficiency Washers and Dryers. Fashion and Textiles, vol. 5, no. 1, 2018, doi:10.1186/s40691-018-0135-3