** Smiths Group SMIN.L gains 2.8% to 2,498p; top gainer on London's FTSE 100 .FTSE
** British engineering firm sells Smiths Detection business for 2 billion pounds ($2.65 billion) to private equity firm CVC Capital Partners CVC.AS
** Co expects net cash proceeds of 1.85 billion pounds; intends to return proceeds to shareholders from deal
** As of last close, SMIN gains 41.36% this year vs FTSE's 7.79% rise
($1 = 0.7547 pounds)
(Reporting by Simone Lobo in Bengaluru)
((Simone.Lobo@thomsonreuters.com, +919920570373))