Apparatus and method for sealing insulated glass units

An apparatus to seal a spacer between a pair of substrates within a generally rectangular insulated glass assembly having side, leading and trailing edge regions, comprising a pair of spaced apart substrates and a bondable spacer therebetween comprising;

• support means for supporting an assembly to be sealed;
• conveyor means to convey said insulated glass assembly along said support means;
• and
• zonal energy applying means to locally apply energy to selected zones of said assembly where said spacer is located without providing direct energy to the balance of said assembly, said zonal energy applying means comprising a first sealing means for simultaneously applying energy and pressure to said leading and trailing edge regions, comprising two pairs of spaced apart opposed members all moveable relative to said support means and a second sealing means for simultaneously applying energy and pressure to the side regions of said insulated glass assembly;
• said support means, conveyor means and zonal energy applying means being arranged for carrying out a sequence of steps on an insulated glass assembly being continuously conveyed wherein energy and pressure are applied first to said leading edge region by a first of said pairs of moveable members travelling with said leading edge region while a second of said pairs of moveable members remains stationary, and a second step wherein the second of said pairs of moveable members applies energy and pressure to said assembly while travelling with said trailing edge region.