An Engineering Analysis Performed on Location

Corning Asahi Video Products (CAV)

3500 E. College Avenue

State College, Pennsylvania 16801-0009

Project Manager: JasonKary

Team Members: Francis Eggles-Darin Imschweiler-Daniel Zerbe

Project Description:

Corning Asahi Video Products manufactures television glass components for production of CRT television bulbs by a variety of television set manufactures. With the emphasis on larger and flatter picture tubes, glass gobs (shown below) have grown substantially over the last year (from 75 lbs to 120 lbs). During gob formation the initial gobs are not press capable and are recycled through the cullet system. The increase in gob mass has resulted in an increase in gob cooling times which has exceeded the current cullet quench system cooling capabilities. This utlimately diminishes gob formation time windows and results in excess line startup times as well as driving cullet recycling cost up.

Project Specifications:

Cool large glass gobs (greater than 75lbs and less than 165lbs)
Cooling must sustain a line rate of 2 cuts/minute
System must be able to cool a hopper of glass in four hours or less
System must be able to run continuously for two hours
System must be able to withstand glass temperatures in excess of 1000°C
System must have a bypass capability without shutting down the gobbing process
System must meet system requirements for space without adding to current facility
System must be maintainable, sustainable, and environmentally feasible
Documentation must be provided to CAV standards
Spatial requirements are as follows:
Distance from floor to platform is 10' 2"
Distance from platform to platform is 18' 4" square
Distance from platform to ceiling is 6' 6"

Preliminary Solutions:

Re-program the Accu-Gob System to make multiple cuts of larger gobs of glass (greater than 75 lbs).
Alter the geometry of the glass gobs to increase surface area and thermal gradients
Implement a more thermally efficient quenching medium to induce breakup of the glass gobs

Final Solution:

A turbulent quenching medium would induce larger temperature gradients and facilitate breakage of the larger gobs. Cooling water is boiled at the surface of the gob and forms a vapor layer. This vapor layer currently remains in the same location relative to the gob.

The 75 lb gobs break up under the current quenching arrangement (without agitation). The 165 lb gobs are larger in radius and temperature gradients are less at the outer edge as a result. The gob then slowly cools without breakage.

Water jets will be lowered over the quench hoppers where they will propel high velocity water (between 10-20 m/s) at the gobs, thereby breaking up the vapor layer. With the no slip condition present, the temperature at the outer edge of the glass will be greatly reduced.

The surface temperature gradient increases proportionally with the severity of quench. Therefore, with adequate agitation, thermal shock will be sufficient to break up the larger radius gobs.

Solution three will be cheaper than solution two. The capital costs will involve a high velocity water pump and re-routing of water piping. Both of these products are readily available from stock supply at CAV. This will decrease costs and reduce the time required for implementation. There will be no long term extra manpower requirements for CAV involved with this solution. For these reasons, solution three seems to be the most appropriate.

The gob is being extruded from the furnace at 1000 degress Celsius

The shears are in position and ready to cut the gob

Cooling hoppers are located underneath to chill the rejected glass gobs