Mueller Holdings Corp. in Annapolis, Md., one...

Mueller Holdings Corp. in Annapolis, Md., one of the nation’s largest makers of fire hydrants, pipeline equipment and related products, has agreed to be sold to Tyco Laboratories Inc. of Exeter, N.H., in a deal valued at $350 million. The value of the sale includes the assumption by Tyco of Mueller’s $260 million in long-term debt. Mueller, which is owned primarily by affiliates of an international investment bank, Investcorp, has more than 3,200 employees at nine plants in the United States, Canada and Britain. The deal is expected to be completed by September.