| When the 18th century Somerset House on England's Thames River was recently refurbished, architects turned an open space that had become a parking lot into a lively fountain of 55 water jets. At night, jets can be individually illuminated in one of 28 different colors thanks to fiber-optic technology and colored filter wheels. |
Those seemingly simple fountains, however are built on a solid foundation of hydraulic engineering, state-of-the-art pumps, piping, compressors, and, in some cases, patented technologies on par with the most advanced aspects of rocket science.
From the simple . . .
Some fountains use a single type of hydraulic device, one that generates vertical plumes. Designers then rely on repetition, geometry, and creative lighting to bring it to life. Somerset House in London, for example, was recently transformed from government offices into an Arts Centre. As part of the project, architects from Donald Insall Assoc., turned a one-time parking lot into an interactive fountain, a 5 3 11 grid of water jets set in 45,000 Portuguese granite paving stones. Each of the 11 rows has a dedicated water pump that puts out up to 140 gpm (28 gpm/jet) enough to let each jet climb 16.5 ft into the air.
| Designers build PVC mock-ups of water effects and test them in a tank at Show Fountains headquarters in Springs, Tex. |
Water is reclaimed and recirculated by a drainage canal surrounding the fountain. It sends water into a 9,500-gallon holding tank where it is filtered, treated with ozone and chlorine, and reused. Typically less than 1% of the water is lost to wind and evaporation on any given day.
Nozzles are set in 6-in.-sq steel plates flush with the pavers. Four fiber-optic lenses surround each jet, and a group of 22 projectors send light to the fountainhead lenses. (Each projector feeds 10 fiber-optic cables.) Two colored gel-wheel filters on each projector combine to illuminate the jets with a choice of 28 possible hues. Using fiber optics and remote-controlled jets means no electrical power is sent to the fountainheads.
| High rollers and tourists seem transfixed by the fountain WET Design created at Bellagio Casino and Hotel. The eight-acre fountain uses 135 miles of wires and cables. When all hydraulic special effects are sending water into the air, the water level in the eight-acre fountain drops 0.25 in. |
. . . to the complex
Of course there are other hydraulic special effects in the fountain designers' toolbox besides the relatively simple vertical jet. Show Fountains in Spring, Tex. (www.showfountains.com), for example, tweaked the vertical jet a bit and turned it into a water lariat. "It's merely a nozzle installed off-axis and mounted on a rotating bearing cup," says Michael Connery, president and CEO of the company. "Rotation comes from water jets on the side of the cup or, if synchronization is critical, we use a motor drive. And mounting several nozzles on one rotating head creates a more elaborate rotating effect." If several lariats are used in a fountain, operators precisely control pump-head pressures to ensure they all spin at the same speed.
Water specialists at WET Design, L.A. (www.wetdesign.com), designed and patented a variation on the water lariat: the Oarsman. It's a self-contained robotic nozzle that includes a variable-frequency drive, pump, and lights. "Operators or a preprogrammed computer feed it electricity and control data, and it responds by positioning the nozzle in the X-Y axis and adjusting its flow rate for just the right stream height," says Tony Freitas, manager of architecture and facility engineering at WET Design. (WET, by the way, stands for Water Entertainment Technology.) "An Oarsman takes water right out of the fountain and pumps it out at up to 120 gpm. There are no water pipes connected to an Oarsman."
Oarsmen were invented for WET's piece de resistance, the eight-acre fountain in front of the Bellagio Hotel and Casino in Las Vegas. They needed a good-sized jet that could gracefully wave back and forth, smoothly change height, spin, and do it all in time to music. The Bellagio fountain originally had 214 Oarsmen installed, but after some on-site testing and fine-tuning, the WET team removed about a dozen.
Before WET could use the Oarsman, however, it had to develop a ground fault circuit interrupter (GFCI) that could handle Oarman's unusual characteristics. "We were using 208-V, three-phase motors, which are not your typical motors, variable-frequency drives for the pump, and stepper motors for moving the nozzles. All this generates noise and harmonics on the line that conventional GFCI see as current leakage," points out Freitas. "But we didn't try to get a variance or get around the regulations, we just went ahead and designed a GFCI."
WET also has vertical jets called Shooters, and they're used at Bellagio, but they differ from those found in other designers' fountains. There's actually a whole line of Shooters that use the same principles, ranging from NanoShooters to Supershooters.
Shooters consist of a receiver for compressed air, a cylindrical holding tank, and some clever valving. In operation, a valve on the holding tank opens, fills with water from the fountain, and closes. A pipe sends compressed air from an equipment room "onshore" to the receiver where it is stored. When the Shooter is "fired," a valve opens, sending compressed air rushing into the holding tank where it becomes an expanding bubble forcing water out of the tank through a nozzle. "So Shooters can't create jets that last all day," explains Freitas. "They're for instantaneous shots. And the bigger the Shooter, the longer it takes to refill the holding tank, so the longer the lag between consecutive shots." Operators control jet height by adjusting the volume of pressurized air released into the holding tank.
NanoShooters, the smallest in the Shooter family, have holding tanks 2 in. in diameter by 18 in. tall and need only a couple pounds of air pressure, yet propel water 10 to 12 ft high. "They're good for interactive displays," says Freitas, "Especially in large numbers when we create a forest of thin, low-force water jets."