The nature of plumbing is such that its most clever innovations usually are obscure to the public eye. People take for granted devices such as the T&P valve, kitchen disposal, flush toilet and so many of our industry's other useful gadgets that have made their lives safer, healthier, more comfortable and convenient. Even plumbers who work with these mechanisms every day tend to lose sight of the ingenuity that went into them.

By spotlighting these great inventions, we hope to instill a greater appreciation for the creativity of our industry's forefathers. Because of space limitations, for this first installment we limited our coverage to the first half of this century. We also wanted to focus on breakthroughs that have withstood the test of time. In future editions of "History of Plumbing," we plan to look at more modern innovations as well.

In compiling this series we tapped the engineering departments and archives of major plumbing manufacturers for guidance. We thank them for their cooperation.

Innovations At Kohler Co.

1926: One of the most advanced products to come out of the 1920s was the Kohler electric sink. It was a combination of a conventional kitchen sink and the electric dishwasher almost as we know it today. The sink was an enameled iron fixture, massive and expensive, half sink and half dishwasher. Invented by Kohler employee Frank Brotz, its only drawback was that it was a generation or two ahead of its time.

1927: Kohler's introduction of bathroom sets (bathtub, toilet and lavatory) in matching colors made fixtures much more than functional. Now instead of stark and sterile white, consumers could choose spring green, lavender, autumn brown, old ivory or horizon blue. For the first time, there was a concern for the aesthetics when planning a bath. However, beyond aesthetic considerations, the color concept was a revolutionary technological achievement in the plumbing industry of the time. The manufacturing of enameled cast iron fixtures and vitreous china fixtures required vastly different raw materials, processes and techniques, so matching color was difficult.

Moen's Single-Handle Mixing Faucet

As the cliché says, Moen's invention rose from necessity. While an engineering student at the University of Washington, Moen worked evenings in a garage to pay his tuition. One day he burned his hands while washing them, using a conventional two-handle faucet. From that experience, he resolved to create a faucet that would give the user water at the desired temperature. His first design was for a double-valve faucet with a cam to control the two valves. Moen showed his designs to a major fixture manufacturer, who showed him why the double-valve was the wrong approach. He then went to a cylindrical design with a piston action. Between 1940 and 1945 he designed several faucets, finally selling the first single-handle mixing faucet in San Francisco in late 1947. Since then, single-handle faucets have become so popular that today they can be found in over 40 percent of American homes.

However, Moen's contributions don't stop with the faucet. His innovative mind also produced the replaceable cartridge, a push-button diverter, back-to-back installation and the swivel spray. For all his achievements, Moen's been nominated for the Inventers Hall of Fame sponsored by the U.S. Patent Office.

Sloan Valve Co.'s Flush Valve

The first flush valves produced by the Sloan Co. were designed for manual operation. Today the state of the art is for flush valves to be sensor-operated to make flushing automatic.

Through the 85 years that the Sloan Valve Co. has manufactured the Royal Flush Valve, about 120 different companies have been in the same business at one time or another. Today only a few remain.

In-Sink-Erator's Disposer

When disposers were first introduced, most municipalities banned them because of worries about their impact on sewage treatment systems. However, by 1960 they were required in new construction by ordinance in more than 100 communities because of their sanitary value. Much like the water closet, a disposer immediately removes raw food waste from the home through sewerage pipes to treatment plants, where it can be treated and neutralized.

After more than 40 years on the market, disposers are now found in more than 50 percent of all households. About 4 million disposers are sold annually.

Halsey Taylor's Double Bubbler

Taylor founded the company that bears his name in 1912. He developed his two-stream Mound building projector, as it was called then, for the U. S. government during World War I. Soon after, in 1926, he perfected and patented what is now known as the Double Bubbler.

Brass-Craft's Flexible Plumbing

Zell's flexible supplies were on the leading edge of the industry's transition from rigid galvanized iron pipe to flexible copper plumbing. These supply lines connected stub-out plumbing from the wall to plumbing fixtures such as faucets and toilets. Flexible copper supplies made it possible for the plumber to design an easily-installed supply stop beneath a sink and toilet. Before this, most homeowners had to turn off all the water to the house to service one leaking faucet.

Delta's Single-Handle Ball Valve

A patent was issued for Perry's ball valve in 1952. Shortly thereafter, Alex Manoogian purchased the rights to the patent and introduced the first Delta faucet in 1954. Manoogian, the founder of the plumbing industry giant Masco Corp., immigrated to the United States in 1920 to escape the genocide of the Armenian Christian minority by Moslem Turkey. His driving ambition was to make enough money to send for his family who had fled to Greece in 1922 to escape the mounting pogroms.

The Delta single-handle faucet was the first to use a ball-valve design and it proved very successful. By 1958, just four years after the product was unveiled, Delta's sales topped $1 million.

Haws' Drinking Faucet

He knew this wasn't a sanitary situation, so when he returned to his plumbing shop he fiddled with some spare parts. Using available plumbing parts - the ball from a brass bedstead and a self-closing rabbit ear valve - Haws assembled the first drinking faucet. He showed his new invention to the Berkeley school department, which installed some of the first models.

Haws eventually gave up the plumbing company and formed the Haws Sanitary Drinking Faucet Co. in Berkeley in 1909. He received a patent on his product in 1911.

Watts' Automatic T&P Valve

Previously, two forms of protection were used. One was the pressure-only relief valve that didn't control temperature, which was the cause of water heater explosions. The second was a fusible plug-type temperature and pressure relief valve. When the water temperature reached 210 degrees F, the lead plug melted. This created a discharge port and the overheated water flowed to atmosphere. The water continued to discharge until manually shut off.

Watt's discovery of the T&P valve has nearly eliminated water heater explosions and ensured that these appliances are safe for home use.

Eljer's Vitreous China Water Cistern

The round cistern was used by Eljer for approximately seven years. In 1908 the company introduced the first rectangular cistern that was cast in a mold - the method used in the plumbing industry today.

Symmons' Pressure-Balancing Shower Valve

Symmons discovered that sudden temperature changes in the shower were caused by pressure changes in the supply lines. Shower water got suddenly hot when someone somewhere else in the building turned on a cold water faucet or flushed a toilet. Conversely, turning on the hot water faucet caused the shower water to turn cold.

Symmons perfected a valve that uses a hydraulic piston as the prime control units. As soon as the valve is turned on, both hot and cold water exert pressure on opposite ends of the piston, balancing it in the valve. If the hot water pressure drops, the piston reacts and reduces the cold inlet opening. The piston continually equalizes the pressure of hot and cold water, even when supply pressures change suddenly or drastically.

Milwaukee Electric Tool's Sawzall

At the time, the only similar tools on the market were drills with reciprocating attachments. They were heavy and required two hands to operate. The Sawzall weighed only 6.74 pounds and, with the right blade, could efficiently rough-out any shape in wood, plaster, metal or plastic.

Whitlam's Ready-Made Pipe Thread Sealant

ITT's Hydronic Technology

In the mid to late 1920s, McDonnell & Miller manufactured automatic boiler waterfeeders to combat the high number of boilers being damaged by dry firing, which is caused by a lack of water. In the early 1930s, McDonnell & Miller was granted a 17-year patent on its development of a cool-water feed valve.