# KBB - August 2009 - (Page 45)

Education Flushed Out Understand the science of toilets Developing a stylish, durable, reliable toilet requires a system involving multiple disciplines of math and science. Physics governs water distribution to ensure effective cleaning of the bowl and to prevent clogging. Mechanical and materials engineering governs valve operation and reliability, and chemistry is needed to understand the properties of clay, glazes, plastics and, increasingly, antimicrobials. Biology is critical to the understanding and controlling of sanitary properties and bacterial growth, and geometry is used to guide aesthetic innovations. Finally, statistical analysis of every element of the toilet design ensures reliable function. If this all sounds like the syllabus from hell, take heart. The science is all behind the scenes, designed with one main objective: better performing, stylish toilets that delight and please your customers. In North America, the washdown method is most commonly used on dual-ﬂush toilets. However, a new generation of dual-ﬂush, high-efﬁciency toilets just now arriving on the market have been reengineered to use siphonic action, increasing the appeal of these water-savers with a larger water spot and less splashing. • Pioneering a New Flush. Engineering a completely new ﬂushing system can take as long as 18 months to develop. As with kitchen and bathroom design, computers now do much of what used to be done by hand. Starting with the aesthetics and performance attributes in highest demand by consumers, a computer-aided design (CAD) model is generated that has the entire geometry of the toilet in a virtual 3D format. The model then undergoes ﬂush simulations using computerized ﬂuid dynamics (CFD), which examines the physics of how the water ﬂows through the Developing a stylish, durable, reliable toilet requires a system involving multiple disciplines of math and science. A FULL CURRICULUM • Flushing Physics. The physics of flushing starts when the toilet is ﬂushed. The tank releases water into the bowl through the ﬂush valve, the opening between the tank and the bowl. In today’s high-performance toilets, some water ﬂows straight into the bowl through a “jet channel,” and some is diverted into the rim of the bowl, where it’s released through small holes to clean the sides of the bowl. As the water level rises in the bowl, it also rises in the up-leg of the inverted U-shaped trapway. When the water reaches the top of the trapway— called the “weir”—gravity pulls it into the downward leg of the inverted U. When the water ﬁlls the entire up-leg and down-leg, gravity pulls additional water over the weir using the cohesive forces in the water itself. Hence the term, “gravity fed.” The rush of water running downhill pulls the waste and water out of the bowl. The stronger the push of the water, the stronger the pull-action created. This pull action is called a siphon. Gravity-fed siphonic toilets are the most common toilets in the Americas. A variation on gravity-fed toilets is a washdown flush. Commonly used in Europe, washdown toilets rely on all “push” and no “pull.” When the toilet is flushed, water floods into a bowl that is noticeably more sharply sloped. This adds more force to the push action, which is ideal for preventing clogs, but can increase splashing. Washdown toilets also typically have a smaller water surface area in the bowl. system under the force of gravity and how it interacts with the surfaces. After the optimum design is determined, it is veriﬁed through a prototype made of advanced polymers. Individual components are bolted together to create a bowl and trapway, and can be easily replaced without having to redo the entire prototype. Although quite Frankenstein-ish in appearance, the prototype can actually be ﬂushed to see if it performs in real life as it did on the computer screen. • Materials Science. Most people know that toilets are made of vitreous china, but not everyone understands why. Vitreous china is an exceptionally strong material. A ﬂoor-mounted vitreous china toilet can literally hold thousands of pounds. It is also essentially as nonporous as a glass vessel and does not absorb water, thus impeding bacterial growth, which requires water. In addition, proprietary glazes give bacteria a one-two punch: antimicrobial elements that inhibit growth and super-smooth surfaces that impede sticking. • Valve Mechanics. Toilet mechanical systems can mean the difference between a satisﬁed customer and repeated callbacks. The best valves and trim available are of impact-resistant, chemically resistant plastics and silicones, the same materials that might be used for protective headgear, aerospace applications and even children’s toys. The quality of materials applied accounts for the new longer warranties now available on toilets, particularly those that also cover the trim. Continued on page 46 www.kbbonline.com / August 2009 July 2004 + K BB 45 http://www.kbbonline.com

KBB - August 2009
Contents
Online Contents
Online News
Editorial
Focus
Trends
Products
Profile
Design
External Analysis
Southern Comfort
Tech
Education
Editorial Index
Favorites

# KBB - August 2009

https://www.nxtbook.com/emerald/kbb/mayjune_2024
https://www.nxtbook.com/emerald/kbb/marapr_2024
https://www.nxtbook.com/emerald/kbb/janfeb_2024_KBISDirectory
https://www.nxtbook.com/emerald/kbb/janfeb_2024
https://www.nxtbook.com/emerald/kbb/novdec_2023
https://www.nxtbook.com/emerald/kbb/septoct_2023
https://www.nxtbook.com/emerald/kbb/julyaugust_2023
https://www.nxtbook.com/emerald/kbb/mayjune_2023
https://www.nxtbook.com/emerald/kbb/202301v2
https://www.nxtbook.com/emerald/kbb/202301
https://www.nxtbook.com/emerald/kbb/202211
https://www.nxtbook.com/emerald/kbb/202209
https://www.nxtbook.com/emerald/kbb/202207
https://www.nxtbook.com/emerald/kbb/202205
https://www.nxtbook.com/emerald/kbb/202203
https://www.nxtbook.com/emerald/kbb/202201
https://www.nxtbook.com/emerald/kbb/202201_v2
https://www.nxtbook.com/emerald/kbb/202111
https://www.nxtbook.com/emerald/kbb/202110
https://www.nxtbook.com/emerald/kbb/202109
https://www.nxtbook.com/emerald/kbb/202107
https://www.nxtbook.com/emerald/kbb/202105
https://www.nxtbook.com/emerald/kbb/202104
https://www.nxtbook.com/nxtbooks/kbb/202102
https://www.nxtbook.com/nxtbooks/kbb/202102_v2
https://www.nxtbook.com/nxtbooks/kbb/202101
https://www.nxtbook.com/nxtbooks/kbb/20201112
https://www.nxtbook.com/nxtbooks/kbb/202010
https://www.nxtbook.com/nxtbooks/kbb/202009
https://www.nxtbook.com/nxtbooks/kbb/20200708
https://www.nxtbook.com/nxtbooks/kbb/20200506
https://www.nxtbook.com/nxtbooks/kbb/202004
https://www.nxtbook.com/nxtbooks/kbb/20200203
https://www.nxtbook.com/nxtbooks/kbb/202001
https://www.nxtbook.com/nxtbooks/kbb/20191112
https://www.nxtbook.com/nxtbooks/kbb/201910
https://www.nxtbook.com/nxtbooks/kbb/201909
https://www.nxtbook.com/nxtbooks/kbb/20190708
https://www.nxtbook.com/nxtbooks/kbb/20190506
https://www.nxtbook.com/nxtbooks/kbb/201904
https://www.nxtbook.com/nxtbooks/kbb/20190203
https://www.nxtbook.com/nxtbooks/kbb/201901
https://www.nxtbook.com/nxtbooks/kbb/201811
https://www.nxtbook.com/nxtbooks/kbb/201810
https://www.nxtbook.com/nxtbooks/kbb/20180910
https://www.nxtbook.com/nxtbooks/kbb/20180708
https://www.nxtbook.com/nxtbooks/kbb/20180506
https://www.nxtbook.com/nxtbooks/kbb/201804
https://www.nxtbook.com/nxtbooks/kbb/20180203
https://www.nxtbook.com/nxtbooks/kbb/201801
https://www.nxtbook.com/nxtbooks/kbb/201711
https://www.nxtbook.com/nxtbooks/kbb/201710
https://www.nxtbook.com/nxtbooks/kbb/201709
https://www.nxtbook.com/nxtbooks/kbb/20170708
https://www.nxtbook.com/nxtbooks/kbb/20170506
https://www.nxtbook.com/nxtbooks/kbb/201704
https://www.nxtbook.com/nxtbooks/kbb/20170203
https://www.nxtbook.com/nxtbooks/kbb/201701
https://www.nxtbook.com/nxtbooks/kbb/20161112
https://www.nxtbook.com/nxtbooks/kbb/201610
https://www.nxtbook.com/nxtbooks/kbb/201609
https://www.nxtbook.com/nxtbooks/kbb/20160708
https://www.nxtbook.com/nxtbooks/kbb/20160506
https://www.nxtbook.com/nxtbooks/kbb/201604
https://www.nxtbook.com/nxtbooks/kbb/20160203
https://www.nxtbook.com/nxtbooks/kbb/201601
https://www.nxtbook.com/nxtbooks/kbb/20151112
https://www.nxtbook.com/nxtbooks/kbb/201510
https://www.nxtbook.com/nxtbooks/kbb/201509
https://www.nxtbook.com/nxtbooks/kbb/20150708
https://www.nxtbook.com/nxtbooks/kbb/20150506
https://www.nxtbook.com/nxtbooks/kbb/201504
https://www.nxtbook.com/nxtbooks/kbb/20150203
https://www.nxtbook.com/nxtbooks/kbb/201501
https://www.nxtbook.com/nxtbooks/kbb/20141112
https://www.nxtbook.com/nxtbooks/kbb/201410
https://www.nxtbook.com/nxtbooks/kbb/201409
https://www.nxtbook.com/nxtbooks/kbb/20140506
https://www.nxtbook.com/nxtbooks/kbb/201404
https://www.nxtbook.com/nxtbooks/kbb/201403
https://www.nxtbook.com/nxtbooks/kbb/201402
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201401
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20131112
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201310
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201309
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20130506
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201304
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201303
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20130102
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20121112
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201209
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20120506
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201204
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201203
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20120102
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201112
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201109
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20110506
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201104
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201103
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20110102
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201011
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201009
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201006
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201004
https://www.nxtbook.com/nxtbooks/nielsen/kbb_201003
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20100102
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20091112
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200909
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200910
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200908
https://www.nxtbook.com/nxtbooks/nielsen/kbb_20090607
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200905
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200904
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200903
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200902
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200901
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200812
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200811
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200810
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200809
https://www.nxtbook.com/nxtbooks/nielsen/kbb_200808
https://www.nxtbookmedia.com