Pyrex Annular Edge Glass. No longer available.
Pyrex® Brand 7740 3/4" Annular Edge
glass is no longer produced by Corning manufacturing company due
to the shutdown of the Sunderland, England manufacturing plant.
This announcement was made by Corning and anticipates not being
able to produce Pyrex® Rolled Sheet, Pyrex® Sight Glass,
reflectors or lens covers.
The only replacement for
Pyrex® brand Annular edge sight glass is the Maxos® annular edge
replacement circles. The Maxos® sight glass is molded for
formulated borosilicate 8488 glass which in comparison gives a
superior quality of cut and ground glass. Maxos® also has
a 3/4" uniform thickness throughout as compared to the 5/8"
minimum thickness of Pyrex® annular edge. The extra
thickness gives boiler operators extra safety for their
The molding process that
Maxos® annular edge replacement glass goes through produces a
uniform product with outstanding optical clarity and greater
thermal shock resistance. Testing procedures subject the glass
to 8 times its rated pressure for maximum user safety. The 8488
borosilicate glass features chemical attack resistance to all
acids except hydrofluoric and hot phosphoric. Maxos® replacement
glass is suitable for temperatures up to 572°F at atmospheric
pressure. Shields may even be used with Maxos® glass as needed
for service conditions to help against some chemical attack. But
note that this will hinder visibility. Maxos® replacement
glass is a direct fit to the Pyrex® equal.