Localized heating of edge seals for a vacuum insulating glass unit, and/or unitized oven for accomplishing the same

A method of making an edge seal for a vacuum insulating glass unit, the method comprising:

• providing an oven including a pre-heating zone, an edge sealing zone, and a cooling zone;
• inserting into the oven a unit comprising first and second substantially parallel spaced-apart glass substrates, one or more edge portions of the substrates to be sealed, and a frit for sealing the edge portions to be sealed;
• in the pre-heating zone of the oven, pre-heating the unit to at least one intermediate temperature, each said intermediate temperature being below a melting point of the first and second substrates and below a melting point of the frit;
• in the edge sealing zone of the oven which is subsequent to the pre-heating zone, providing, via a localized heat source, localized heat to the unit proximate to the edge portions to be sealed at at least a frit melting temperature, the frit melting temperature being sufficiently high enough to at least partially melt the frit, the localized heat being provided to the unit such that areas of the unit not proximate to the edge portions to be sealed are maintained at a temperature proximate to an intermediate temperature(s);
• and
• in the cooling zone of the oven, cooling the unit in its entirety to at least one reduced temperature and allowing the frit to harden in making the vacuum insulating glass unit.

An apparatus for forming edge seals for vacuum insulating glass units, comprising:

• a pre-heating zone for receiving a unit comprising first and second substantially parallel spaced-apart glass substrates, one or more edge portions between the first and second substrates to be sealed, and a frit for sealing a periphery of the substrates, and the pre-heating zone being for pre-heating the unit in its entirety to at least one intermediate temperature, each said intermediate temperature being below a melting point of the first and second substrates and below a melting point of the frit;
• an edge sealing zone located subsequent to the pre-heating zone, the edge sealing zone including a localized heat source for providing localized heat to the unit proximate to the edge portions to be sealed at a frit melting temperature, the frit melting temperature being sufficiently high enough to melt the frit, the localized heat being provided to the unit such that areas of the unit not proximate to the edge portions to be sealed are maintained at a temperature close to an intermediate temperature;
• and
• a cooling zone of the oven for cooling the unit in its entirety to at least one reduced temperature and allowing the frit to harden.

A method of making a vacuum insulating glass (VIG) window unit, the method comprising:

• providing first and second substantially parallel spaced-apart glass substrates and a frit provided at least partially between the first and second glass substrates for sealing an edge of the VIG window unit;
• pre-heating the glass substrates and the frit to at least one temperature below a melting point of the first and second substrates and below a melting point of the frit;
• after the pre-heating, providing localized near infrared (IR) inclusive heat proximate to the edge to be sealed so as to at least partially melt the frit;
• and
• cooling the unit and allowing the frit to harden in making the vacuum insulating glass (VIG) window unit.