A fire early Sunday at a home in northeast Fort Worth sent three children and their grandfather to the hospital -- two of the children with severe burns.A smoke detector was found in the house -- which is located in the 2600 block of Chenault Street -- but it was not in working order, said Lt. Kent Worley, Fort Worth Fire Department spokesman.A 3-year-old girl suffered third-degree burns, and a 1-year-old boy suffered second-degree burns, Worley said.