HIGH STANDARD VALVES FOR NON-STANDARD CONDITIONS Zwick is a leading manufacturer of metal-seated triple offset butterfly valv ... es known as series TRI-CON, the check valves, called TRI-CHECK and the TRI-BLOCK series, Zwick’s Double Block and Bleed Design. 30 years experience in design and production of valves guarantee high standard products. ZWICK valves are produced with state-of-the-art machines. The triple offset butterfly valves are specially designed for critical services where they are used as shut off and control valves. The in-house design enables offering customized solutions for individual applications like the global Industries of Oil and Gas, Chemical, Petrochemical, Energy, Offshore and Steel with shortest delivery times. read more