The casting design team used simulation software to explore hot spots (left) and porosity (right) that might occur in the casting. Working together, the customer and metalcaster were able to reach a castable design that served the customer’s needs.
design is to make the municipal water- works equipment safer, more reliable, less risky for property and civilians and greener, wasting less water than traditional hydrants. In addition to deterring vandals, the company says the Spartan is more resistant to weather corrosion and requires less maintenance than its predecessors. “We’ve achieved standards for the
certifi cation of hydrants that have never before been done,” Sigelakis said. “Because of the design and the casting quality, we are able to reach 300 psi working pressure on a hydrant, higher pressures than [any other hydrant].”
The Evolution of an Idea T e body casting of the Spartan
hydrant is more than just a clamshell. It includes complex interior passage- ways that scared off several potential casting suppliers early in the 15 years
of research and development Sigela- kis has put into the hydrant. When the Sigelock engineers delivered their original design to Waupaca, the response was diff erent. “T e working relationship was great
from the fi rst day I met [Sigelakis],” said Shelby Applegate, Waupaca’s lead engineer on the project. According to Applegate, the
Sigelock team was willing to alter the design in whatever way was necessary to achieve a part that was castable at a reasonable cost. While the origi- nal design required a fi ve-piece core assembly, the team was able to whittle that down to two. T e reduction was instrumental in achieving a 37% price break from the original design. One of the critical elements of
the redesign and reduction of cores was a change in the drainage valve originally situated at the bottom rear
of the casting. During rain storms or other precipitation, hydrants can collect water, which needs to be released from the body. The drain hole originally put in place by Sigelakis and his team was not in an ideal spot to be cast. According to Applegate, the 0.5-0.625-in. hole had to be removed to achieve the simpler core package. “We originally had a drain hole
in the rear,” Sigelakis said. “We eliminated the drain hole and instead created two channels under the tongue [to allow drainage]. Additionally, it also protects the tongue and helps hold the core in place.” Applegate said several other
changes completed the reduction in the number of cores used, including a change in the draft on the front cap at the top of the hydrant so that the cores could be drawn naturally (i.e., removed
Because simulation software predicted a large section of porosity in the solid section at the top of the hydrant, a hole was added to aid in solidifi cation, as indicated by the arrow at right.
October 2011 MODERN CASTING | 31
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