Cliente: San Diego County Water Authority
Producto: VAG RIKO® Plunger Valves
San Diego, the eighth largest city in the United States, is situated on the southern tip of California near the Mexican border. With the Pacific Ocean as its western border, this coastal city of 1.3 million is known as "surfers' paradise." It is also home to the largest naval fleet in the world and is one of the world's prominent wireless communication and biotech industrial hubs.
But nearly nine out of ten gallons of the county’s drinking water has to be imported from the far north of the state. The San Diego County Water Authority (SDCWA) provides safe and reliable water to the county of San Diego (approx three million inhabitants) through large-diameter water transmission pipelines, reservoirs and flow-control facilities. At its Escondido Crossover Pipeline Terminal Station, the Water Authority operated two plug valves to regulate flows in hundreds of miles of its transmission pipeline systems.
The former installed plug valves used at the terminal station had difficulty withstanding the extreme stresses caused by excessive cavitation and vibration when the pressure across the valves had to be reduced by some 100 psi for an extended period of time. Local residents complained about unbearable cavitation noise and vibration that not only badly damaged the valves, but nearby homes too. What's more, the valves had to be replaced every three to five years. That got the Water Authority's staff thinking: "Are there any valves that are more resistant to cavitation and vibration and hence have a longer service life? Could such valves be what we need? Can we find a better solution?"
The Water Authority started looking for valve manufacturers around the world and found what they were looking for at VAG-Armaturen in Germany. Would VAG's Plunger Valve be an alternative and could it be adapted to American standards and specifications? The SDCWA had never worked with VAG before and was somewhat skeptical at the beginning. On the other hand, the problems were getting worse and no other manufacturer could help solve them.
So in February 2006, SDCWA contacted VAG USA who recommended two custom VAG Plunger Valves. This meant becoming familiar with American hydraulic and cavitation standards, measuring units, material descriptions, manufacturing approaches, etc. In short, VAG had to understand the American way as quickly as possible. VAG succeeded, and for the first time was asked to submit a tender in this sector. The contract was awarded in August 2006 following the official invitation to tender. This meant that everyone had to stick to the very tight schedule that was put in place for the pipeline system shutdown. Because the shutdown had such a big impact on the region, SDCWA only planned a seven day window within which the plunger valves had to be installed.
For VAG, this meant that the construction, material calculations, flange standards, coating systems, custom actuators, production, permits, documentation and delivery all had to be done "Just-in-Time" by March 1, 2007. Based on the analysis of the hydraulic conditions in the pipeline’s network, VAG made a special custom control outlet for its plunger valves. The objective was to achieve a control behavior that respects all clients' flow and pressure requirements for cavitation-free operation conditions.
In January 2007, Gary Stine, Operations & Maintenance Manager, and Steve Carpenter, Maintenance Supervisor of SDCWA, visited VAG's manufacturing plant in Mannheim, Germany for the final inspection of the plunger valves. They were convinced that their first two plunger valves "Made in Germany" would be successful and wanted to get an impression of VAG, in particular with regard to a longterm collaboration. They were given a tour of the manufacturing plant and the VAG Visitor Center and spoke with engineering and service experts. They then visited a number of reference projects in Germany. The American delegation was very interested in and impressed by the variety of solutions used to solve the various challenges faced across Europe.
In the meantime, the two giant plunger valves had been securely packaged and were on their way to the United States by ship. Due to the tight schedule, the transportation was subcontracted to a specialized company. The back-up plan for shipment by airfreight was not needed thanks to the excellent project management and the support of the various departments at VAG. Just in time, two days before the plunger valves were scheduled to be installed, they reached their final destination — the terminal station.
Auma USA's staff was ready and waiting to connect the actuators and put them into operation. As a precaution, the Water Authority also ordered two conventional plug valves to prepare for the pipeline shutdown in the event that complications delayed the delivery of the plunger valves. March 16, 2007, the day everyone had worked toward so hard, came and went without a problem. The assembly and installation of the two 36-inch plunger valves ran like clockwork — everything went according to plan. Then came the moment of truth: putting the valves into operation.
It took just minutes for everyone to realize that the new plunger valves didn‘t vibrate. The maximum noise level of 95 dba met the specification requirement, and was much lower than that of the previous valves. The noise level was confirmed by a sound level monitor installed inside the valve vault (see picture below). The lower noise level would not only enable the nearby residents to sleep better, it would also put a stop to the extensive wear and tear on the valves and downstream pipes at the terminal station.
After two years of pilot operation, the plunger valves met or exceeded the Water Authority’s expectations. SDCWA’s staff was thrilled.'The pilot project went really well. We can now stop using the other control valves, which proved to be unsuitable for this terminal station. We are really pleased to have found a competent manufacturer in VAG, and intend to equip more of our flow control stations with custom VAG Plunger Valves,' Steve Carpenter explains.
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