Charles Ross & Son Co., a Hauppauge maker of industrial mixing and blending equipment, has opened its largest manufacturing facility, in Wuxi, China, the company said.

The 250,000-square-foot factory with 350 employees is scheduled to have a grand opening on March 25, said Joseph Martorana, vice president of corporate operations.

The company, with annual sales of about $100 million, has a total of eight plants in the United States, India and China.

The 18-year-old Chinese subsidiary, Ross Wuxi, makes mixers for pharmaceutical processing, adhesives production and chemicals used to make lithium ion batteries for cellphones and computers. The new factory is triple the size of the previous Chinese facility it replaces, Martorana said. He said the facility was built “to take advantage of lower Chinese wages and capture the local manufacturing growth within China.”

The company employs 550 people worldwide, including 52 at Long Island locations in Hauppauge and Deer Park. The company also has domestic facilities in Port St. Lucie, Florida, and two in Savannah, Georgia.

The company’s storage vessels and mixing and blending equipment range in size from a half-pint to 80,000 gallons.

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Martorana said the 175-year-old company is in the process of doubling the size of its Pune, India, facility to 40,000 square feet.

In 1999 the family-owned company created an employee stock ownership plan to give workers a stake in the company.