The maker of fire and gas detection and navigation and emission monitoring systems for ships, properties, transportation and the oil and gas industry said it had agreed to sell the division to private equity firm Nordic Capital.
Its shares were up 196% at 0906 GMT.
"The proposed transaction enables the freeing up of considerable worth for Consilium's shareholders, and allows Consilium to focus on growth within remaining businesses," the company said in a statement on Saturday.
Consilium said it expects a capital gain of around 1.55 billion crowns or 132 crowns per share from the sale of the division, which last year had a turnover of 1.35 billion crowns - 95% of group turnover.
The board plans to use the proceeds to invest in remaining operations and to pay back loans, and will also propose an extra dividend, Consilium said.
Platanen Holding, which controls 72% of votes in Consilium, has undertaken to vote in favour of the deal at an extraordinary shareholder meeting and the deal is expected to be finalised in March or April 2020, it said.
Consilium, which has sold or closed down segments in recent years to streamline its business, has this year been looking into strategic alternatives for its remaining operations.
(Reporting by Anna Ringstrom; editing by Jason Neely)