Zero leakage and modulating functions in one valve
Zwick Armaturen
In collaboration with Yeary Controls, this company has developed the patented throttling trim cartridge Sharktooth, which is used to turn its triple-offset butterfly valves into excellent control valves. This revised design is equal in control performance to a globe valve or rotary plug valve, but incorporates much better shutoff capabilities, says the company. By combining the throttling trim cartridge Sharktooth together with the triple-offset butterfly valve series Tri-Con, the Tri-Shark is a zero leakage shutoff and control triple-offset butterfly valve. This control valve has all the advantages of triple eccentric butterfly valves while operating as a control valve. Now, just one style of valve can be used for both, on-off and control applications. The throttling trim cartridge (photo) is designed closed to the pivoting motion of the valve’s disc to keep the flow between disc and cartridge as low as possible. Furthermore the cartridge is manufactured with multiple optimized slots, which divide the flow and clear an exact calculated cross-section while opening or closing the valve. With the throttling trim cartridge, the valve’s flow characteristic is changed to an equal percentage flow characteristic, which is known as the preferred inherent flow characteristic for the majority of control applications. Tri-Shark’s flow characteristic makes sure that the valve is able to provide an effective control range at 5 up to 30 deg of travel, the control area where traditional triple eccentric butterfly valves seem to reach their limits. Hall 3, Stand A92 — Zwick Armaturen GmbH, Ennepetal, Germany