BC Partners, an international private equity firm and global alternative asset manager The Carlyle Group have signed a definitive agreement to acquire Hamilton Sunstrand Corp.’s industrial businesses, including Sullair, a leading compressor manufacturer that concentrates exclusively on rotary screw technology. Based in Michigan City, Ind., with subsidiaries in Australia and China, Sullair is a manufacturer of compressed air contaminant removal equipment, vacuum systems, stationary and portable compressors and contractors’ air tools.

BC Partners and The Carlyle Group are buying Hamilton Sunstrand from parent company United Technologies Corp. for $3.46 billion. The transaction is expected to close in the fourth quarter. Additional third-party debt will be provided by a banking consortium. BC and Carlyle have formed a limited partnership and will jointly oversee management of Sullair. The companies plan to increase investment in the company’s product development activities and to leverage the global footprints of both firms to enable the company to accelerate its growth.

“The partnership between Carlyle and BC Partners provides a unique growth opportunity for Sullair,” said Henry Brooks, Sullair Corp. president. “They recognize that our business is a performance leader in our markets with great employees, great products, and vested channel partners. Additional investment in Sullair will enhance our capabilities to compete on a global scale.”

Sullair’s compressors are well known in the energy, mining and chemicals industries, and the company is a supplier to a wide variety of equipment rental companies.

The Carlyle Group, which has about $159 billion of assets under management, has been an active investor in the equipment rental industry, with ownership stakes in Hertz Global Holdings, owner of Hertz Equipment Rental Corp., as well as Coates Hire, Australia’s leading equipment rental company.