Swedish shot-stopper, Ohman, began his career in his home country before featuring for Whitehawk and Egham Town.
Ohman, 21, joins the Clarets on a non-contract basis and will provide competition for number one goalkeeper Ross Worner.
In addition to the signing of Ohman, the Clarets are pleased to welcome Matt Foy to the Club.
Foy, 19, joins the Clarets on an initial one month loan from Cambridge United.
The young centre forward has failed to make an appearance for the Sky Bet League Two outfit, featuring on various loan spells at Cambridge City, St Neots Town and Lowestoft Town.
Both players are available for selection for the Clarets' Vanarama National League South opener against Torquay United tomorrow afternoon.
All at Chelmsford City Football Club welcome Patrick and Matt to the Melbourne Community Stadium.
Updated 20:25 - 4 Aug 2018 by Steve Parker