HANSEN TECHNOLOGIES CORP., Burr Ridge, Ill., has added new international sales representatives: M.Y. CHYE will cover Asia and the Pacific Rim, and ERNESTO RODRIGUEZ will handle Latin America. In addition, the company added two American sales representatives: RAY FICKER is responsible for Wisconsin, Michigan, Indiana, Ohio, Kentucky and West Virginia; PAUL VAN EVERY will cover the Western United States and Canada. Hansen manufactures components for industrial refrigeration systems.

The company also has announced that it will now accept MasterCard, VISA and American Express as payment options.

DUNHAM-BUSH, Harrisonburg, Va., appointed BILL RIAL as president. Rial was previously vice president of sales, marketing and service for

the company. In addition, the company appointed BRAD BAINES as vice president/general manager. He previously was a consultant for Dunham-Bush.

DWAYNE STONE of Kansas City, Mo.-based BLACK & VEATCH CORP. has been appointed president of the engineering and construction company's process division.

ULTRAFILTER INC., Norcross, Ga., part of the ULTRAFILTER INTERNATIONAL GROUP, Haan, Ger-many, appointed CHRIS M. ULERICK as marketing director of its new chiller division.

RITTAL CORP., Springfield, Ohio, has appointed MICHAEL BEYER as president. Beyer is replacing HANS J. WAGNER after Wagner was diagnosed with a degenerative eye disease. In addition, the company has promoted PETER B. KOKUZIAN to senior vice president, sales and marketing, JAMES B. HIRT to senior vice president, operations, and DAVID W. WATSON to senior vice president, finance and administration.