By spotlighting these inventions of significance, we pay tribute to the innovators of the past and hope to instill a greater appreciation of the PHC trade heritage. We also hope to instill better understanding of how certain products work.

In producing this year's installment of "Greatest Plumbing Inventions," we required that all items submitted for consideration had to be invented prior to 1975. We wanted to focus on innovations that have withstood a test of time, as opposed to those that may prove to be passing fancies or reveal unforeseen defects a few years down the road.

The information presented comes from the engineering departments and archives of the companies featured. We thank them for their cooperation.

Spirotherm's Air Eliminator

The cyclical growth and release of microbubbles, due to temperature changes, led to faulty test results. Last century, the theory behind this absorption process was already described in Henry's Law stating that the amount of gas absorbed by a liquid is defined by temperature and pressure.

A research project eventually led to the creation of the Spirovent air eliminator. The special Spirotube inside the Spirovent proved to be the essential part that separated all air, including microbubbles, originating in the heat source. This enabled water to absorb even trapped air at remote and inaccessible areas. In conjunction with a reliable air valve mechanism, without a cap to insure uninterrupted working, it became a mature product ready for mass production.

Today, Spirovent helps eliminate annoying noises from circulators and piping, along with high maintenance costs and callbacks for manual bleeding of hydronic heating or chilled water systems.

Cherne Industries' Test-Ball Plug

He was on a job in northern Michigan when, much to his dismay, the cast iron mechanical plug he was using (the only plug available at that time) to conduct the stack test would not fit through the cleanout tee. So he purchased a rubber playground ball from a Woolworth store, vulcanized a stem on it and came up with a crude pneumatic test plug.

Returning to his home base in Minnesota weeks later, Lloyd began experimenting with his idea and within six months began making Test-Balls similar in design to the same style Cherne Industries makes today, bringing them to market in 1953.

The Cherne invention simplified the steps taken to test plumbing in a building, and greatly contributed to the now universally accepted practice of mandatory testing. The plumber now had a test plug that could be used in all common pipe I.D.s, that could conform to out-of-round pipe, that was guaranteed to handle common test pressures and, best of all, was much safer when used with an extension hose than cast iron mechanical plugs.

Initially produced in sizes 1-1/4 inches through 6 inches and catering only to the plumbing trade, the company eventually developed pneumatic plugs up to 120 inches in diameter, serving virtually any pipeline need throughout the world.

Elkay Takes Pressure Off The Cooling Tank

Until then, most water cooler tanks were kept under pressure. Elkay engineers noted that with cold water under continual pressure within a cooler, a water leak or rupture could develop overnight or over a weekend, going undetected for many hours or days and causing extensive damage to the surroundings.

In the new design, the only water under pressure was the water from the source up to the valve and the regulator cartridge. When activated, the push button valve opened to allow water to slow into the cooling tank and then out the bubbler. In the unlikely event of a burst tank, only the stored water within the cooling tank would be released.

Halsey Taylor's Combination Coolers

These are but a few of the conveniences provided by our industry that modern America takes for granted. The elder statesmen and women among us grew up in an era when life was not so easy, however.

That's why Halsey Taylor in the 1920s made a big impact with its line of "Combination Cooler and Drinking Fountains," as they were advertised. This depiction from a 1925 catalog shows a cutaway view of a product with a 19- by 19-inch ice chamber, 80-pound. ice capacity and ice consumption of approximately 1 pound per capita per day. The drinking water did not come into direct contact with either the ice or melted ice water, but was circulated through a brass coil tinned both inside and outside.

What did a state-of-the-art Automatic Control Combination Cooler & Drinking Fountain sell for in those days? É $72.

The T-DRILL System

Mechanical formation of tee connections had been around for many years, but Larikka developed a more sophisticated method that became the most widely adapted system of its kind in the world. In fact, in Scandinavia they do not put in tees- they put in "Larikkas," just as we use "Kleenex" tissues and "Xerox" documents. Patents were not pursued until the early 1970s, though the second- and third-generation T-DRILLS have since been patented.

As plumbing wholesalers are few and far between in Finland, Larikka developed his invention out of necessity. Lacking the right size tee fitting, he came up with a way to create what he needed out of the tube itself.

Before this method of installation could be widely used in North America, national, state and local codes had to be rewritten after suitable testing. Now, 15 years after introduction here, most plumbing codes are complied with and the method is in compliance with ANSI B 31.5 (ASME code for pressure piping) and being used by over 5,000 plumbing, mechanical and sprinkler firms.

The fast-track installation afforded also necessitated special inclusion in labor calculator manuals. According to the company, three out of the four major plumbing and mechanical cost data books now reference the Mechanically Formed Tee Connection.

Wirsbo PEX Tubing

PEX tubing solved a number of problems that occurred with metal pipes and some other types of plastic tubing. PEX will not corrode or erode, and is immune to the many problems associated with poor water quality that can damage metal pipes. The tubing is rated at 180 degrees F., 100 psi. Wirsbo tubing also has the highest polymer oxygen diffusion barrier of any tubing in the world, according to the company.

The growth of cross-linked polyethylene tubing has been dramatic in the European market. Today about 10 percent of all plumbing installations are made with PEX tubing, and in some countries over 50 percent. In Europe, where radiant floor heating is installed in over 50 percent of all new construction, PEX tubing goes into approximately 70 percent of all jobs.

Wirsbo-PEX was introduced to the U.S. plumbing market in 1985 by Tomas Lenman. Now director of technology at Wirsbo Co. in Apple Valley, Minn., Lenman was a leading member of the engineering team that developed the product in the early 1970s. Today, PEX tubing products are used for floor heating and other heating applications.

Powers' Pressure Balancing Initiatives

The 410 utilized a unique diaphragm-actuated pressure equalizing chamber to sense and correct any change in the water supply. Failure of the cold water supply shut off hot water delivery to protect the bather.

Rugged construction made the valve well-suited for high-use shower applications in hotels, apartment buildings and schools. Powers advertised the Series 410 as a great way to "shower a welcome" on hotel and motel guests É and keep apartment tenants singing as they soap up!

The concept of controlling water temperature through pressure control dates back to 1887, when company founder William Penn Powers equipped his new three-story heating/plumbing business building with Wisconsin's first central water heating plant.

To eliminate boil-over, he developed a process of controlling the system based on the relative boiling points of water under different pressures. He achieved it via a closed-end, water-filled pipe in the boiler, the other end of which was attached to a diaphragm that controlled a damper.

Slant/Fin's Heat Exchange Fins & Assembly

Prior to this invention, finned tube radiation frequently got distorted by handling during installation with a consequent reduction in heating output. Making the individual fins thicker and stiffer helped resist distortion, but also made the radiation clumsier to handle and thereby led to rough treatment. Heavy fins also had sharp or rough edges due to their manufacturing process, presenting a hazard to the installer. Still another drawback was the "reed" effect, a vibration resulting from temperature changes.

The heat exchange fin concept eliminated these drawbacks via an interlocking and fin-touch-fin design. When assembled, these fins supported one another for added strength. Accordingly, the individual fins could be made of lighter-weight material without sacrificing durability.

A result was greater heat transfer, enhanced by the flue effect introduced by the side engagement of the fins in the assembly. The lighter-weight fin material also made for quicker space heating. In addition, the fins were devoid of corners and edges and thus less likely to cause injury. Finally, their interlocking arrangements enabled them to maintain constant contact, which eliminates the "reed" effect.