The HORN® forehearth GCS 300 system works with indirect centreline air cooling while the forehearth GCS 301 system works with both indirect and direct centreline air cooling.
Both forehearth systems are characterised by the most advanced technology in forehearth design for high-pull forehearths and the highest temperature homogeneity requirements (K-factor). The refractory structure design is an up to date modern construction employing all today’s techniques to achieve optimum thermal homogeneity combined with minimum energy requirement.
High quality refractory material is used for channel blocks. All channel block joints are backed up with zircon mullite split tiles and are surrounded with suitably graded insulation material for minimum loss of energy.
The roof blocks of the superstructure in the cooling sections are of a special shape to separate the atmosphere above the glass bath in a left, middle and right area. The heating of the glass bath in the left and right area is also assisted by reflected flame radiation, due to the inclined design of parts of the roof block. This design provides a reduction in the temperature difference in the glass between the centre and the outer areas of the channel.
The GCS Series 301 is based on the design of the GCS Series 300 with an additional direct forced cooling system to increase response time and flexibility when a wide range of gob temperatures is required. Therefore special roof cover blocks for area separation along the control zones are installed. This results in:
- separated boundary areas to heat the glass particularly at the side of the forehearth
- separated central section to guide direct cooling air.
In addition, the roof contains a separated channel for indirect centerline cooling.
At glass contact, conventional channel design with different refractory qualities is possible (e.g. BPAL, HPAL, Alpha-Alumina, fused cast).
Waste gas openings (chimneys)
The waste gas openings are small openings which are arranged laterally at the outside of the particular zones in order to draw the waste gas to the outside area of the glass in order to heat them significantly. By exact adjustment of the dampers, the residence time of the waste gas moving along the outer area can be controlled.
Radiation openings are foreseen in the forehearth superstructure at the beginning of each cooling zone. Through adjustment of the damper block above the radiation opening, the heat radiation through the opening is variable. In addition, by adjustment of the dampers, the residence time of the waste gas moving into the central area of the forehearth can be controlled.
Centreline top cooling (indirect)
All cooling zones are constructed with a central channel inside the refractory superstructure. This channel stretches across approximately 70% of the length of the cooling zone.
Between glass surface and cooling channel, slots are positioned to channel heat radiation from the glass to a “heat exchanger plate” with profiled surface for heat convection purposes.Cooling air provided by a fan can be blown through the channel against the glass flow direction and extracts the heat through convection on the “heat exchanger plate”.
Centreline top cooling (direct)
Direct cooling air is applied onto the glass surface in the central section of the forehearth. The cooling air is inserted via holes in the mantle block by fans. Then the cooling air is channelled between the separated boundary areas, underneath the superstructure, and leaves the forehearth through the central radiation opening.
In order to “spread” the air layer on the glass surface to the right and/or left boundary sections, the air can also be released via the right and/or left lateral chimneys.
Centreline bottom cooling
The bottom cooling works according to the same principle as the top cooling. The cooling channel is located under the channel blocks, in the entrance zone of the forehearth.
The bottom cooling channel is a standard installation in GCS Series 200, 300 and 301 for the subsequent installation of a blower in case the product profile changes.