Surgebuster Check Valves Halt Slam at UCONN Pumping Station
“Our old valves slammed so hard, the building would shake!” recalls Ken Pelzar, superintendent of the waste water treatment facility at the University of Connecticut’s Storrs campus. A Surgebuster application.
Fast flow reversals and water hammer can result when pumping applications deal with high head, surge tanks or multiple pumps. The UCONN facility pumps waste water 250 feet uphill. As soon as power shut off, water surged back at high velocity.
Says Pelzar, “Since we installed four 6-inch Val-Matic Surgebuster check valves, you can barely hear the valves close.”
With Surgebusters, Harper solved two additional problems for Pelzar – excess wear and poor valve function. Previously, sand and stones in the flow were wearing out the gaskets and preventing the seat from sealing properly when the flow reversed. UCONN now expects the valves and other parts to last much longer, reducing maintenance costs at the pumping station.
A Skeptic is Converted
Pelzar’s supervisor knew Harper International from a previous project and suggested Fred Haines might be able to help. “I was really skeptical when I first saw the simulation on Fred’s laptop,” said Pelzar. “A lot of things that are possible in a lab don’t work that well on site. But we’ve had the Surgebusters in for a month, and so far we are really pleased. It’s amazing how quiet it is now.”
The Surgebuster check valve is specifically engineered to handle extreme applications, where systems are known to surge, by closing very rapidly using a short disc stroke of 35 degrees while still maintaining a 100% flow area. “The valve stroke is one-third the arc of our old valve,” says Pelzer about the Surgebuster. By closing so swiftly, the Surgebuster prevents reverse flow from developing and causing a slam. (VIEW CHART.)
Surgebuster is engineered to last much longer than conventional swing check valves. Fabricated of ductile iron material (ASTMA 576), the standard Surgebuster provides significantly more tensile strength than cast iron. Surgebuster’s rubber flapper has been cycle-tested for 1 million cycles, and its fusion bonded expoxy coating is also standard. These features combine to give Surgebuster a longer life with less maintenance.
Just Two Moving Parts
The Surgebuster is a non-clog design with only two moving parts. (See the video.)
What makes the valve unique is its patented Disc Accelerator. This feature is a precision formed stainless steel mechanism that closes the disc rapidly, avoiding any slamming by flow reversal while also allowing the disc to be stabilized under flow conditions. The accelerator is fully enclosed within the swing check valve and out of the flow path, and fully meets ANSI/AWWA C508.
Traditional swing check valves use outside levers with weights or springs in an attempt to reduce slam. By doing so, they pull the disk down into the flow and reduce the length of the disc stroke so that it closes faster.
Unfortunately, while outside levers and weights help solve one problem, they create others. Increased headloss and maintenance are inevitable with traditional swing check valves. Pulling the disc down into the flow creates a blockage in the line and causes tremendous headloss and turbulence. With the disc oscillating in the flow, the shaft, bearings, and shaft seal are all subjected to severe wear and reduced service life.
Surgebuster’s self-contained design also eliminates the need to enclose the valve in a safety cage. Conventional swing check valves have been implicated in serious accidents, where maintenance workers have been injured when the swing-check arm rotated suddenly with great force. To combat this hazard, OSHA recently began requiring safety cages for conventional swing check valves.