Firing system GADP

General description
An energy-efficient forehearth and distributor combustion system designed for consistent quality production in the glass industry. The system is based on premix gas/air technology and can be used with natural gas or LPG. Developed from over 22 years of application experience, it is suitable for special and coloured glasses where stable redox conditions in the forehearth superstructure are essential for quality production.

Key features

• Premix gas/air combustion system for forehearths and distributors
• Compatible with natural gas or LPG
• Engineered to maintain a stable gas/air ratio and redox conditions for special and coloured glass
• Preassembled compact combustion skids, ready for installation

GADP Combustion System
The GADP system is based on a constant ratio between the differential pressure (DP) at the air orifice plate and the gas regulation valve. It resists effects from burner pressure fluctuations or partially blocked nozzles. The GADP manifold pressure range is 6–50 mbar. Burners are supplied for both low- and high-pressure applications.

GADP - Main benefits

• Correct combustion ratio across full flow range (3–50 mbar manifold pressure)
• Linear valve control characteristic for predictable response
• Stable ratio during burner pressure fluctuations
• Maintains ratio after burner nozzle change or cleaning
• Easy and precise manual gas/air ratio adjustment per zone
• Wide range of flows and sizes (DN25 to DN100)

Standard Mixer - Zero Governor (ZGT)
The standard venturi mixer with zero governor is a common solution across glass types (tableware, containers, special glass). The ZGT has been improved to enhance performance and long-term gas/air ratio stability. The zero governor pressure tapping is positioned upstream of the venturi mixer to extend ratio range and reduce leakage risk. ZGT pressure range is 3–50 mbar and is suitable for low- and high-pressure burner systems; it is recommended for container production.

ZGT - Main characteristics

• Linear air valve
• Manual maximum air flow setting (curtain) per zone
• High loop control stability
• Consistent ratio stability across the full operating range
• Pressure tapping upstream of the mixer
• Independent ratio control per zone
• Recommended for container industries

OMN Combustion System
The OMN concept uses an air orifice plate and a double-stage zero governor with pressure tapping upstream of the orifice plate flange chamber. Gas is introduced downstream and regulated by a high-precision gas needle valve. Orifice plate and needle valve sizes are tailored to each combustion zone. The double-stage zero governor increases ratio stability across the full range and in real time. OMN is recommended for high-performance forehearths in container industries, including green and amber glasses.

OMN - Main benefits

• High ratio stability over the full operating range
• Long-term ratio stability with minimal adjustments
• Pressure tapping upstream of the mixer
• Independent ratio control per zone
• Capability to operate over a wide range of ratios
• High-precision gas regulating needle valve
• Air orifice and gas needle sizes customized per zone for improved fuel efficiency

Construction details & skid features
The combustion skids for forehearths and distributors are compact, preassembled and supplied with up-to-date equipment for reliable operation. Each zone is fitted with the required technology (ZGT, GADP, OMN) as specified. Typical skid equipment includes:

• Pressure indicator per zone
• Pressure transmitter per zone
• Explosion relief valve per zone
• Gas flow meter per forehearth or distributor
• Mix test analysis connection per zone
• Air and gas pressure switches
• Skid cabling and local junction box

Burners & manifold
Burners are manufactured from high-temperature resistant steel and sealed to the refractories. Each manifold is supplied with long flexible connections and manual shut-off valves for maintenance. Standard burner nozzle sizes include:

• 1/4 inches / 6.3 mm
• 3/8 inches / 9.5 mm
• 9/32 inches / 7.1 mm
• 5/16 inches / 7.9 mm

Additional notes
Systems are designed to maintain stable ratio control even with dirty or partially blocked nozzles. Options include skid-mounted combustion air fans with inverter or direct drives and gas governor redundancy skids where required.

Technical specifications

• Combustion types supported: ZGT (zero governor), GADP, OMN
• Fuel: Natural gas or LPG
• System type: Premix gas/air
• Recommended use: Containers, tableware, special coloured glass (e.g. green, amber)
• Operating manifold/pressure ranges: ZGT / OMN: 3–50 mbar; GADP: 6–50 mbar
• Skid features: Preassembled combustion skid per zone with indicators, transmitters, explosion relief, gas flow meters, test connections, pressure switches and local junction box
• Burner construction: High-temperature resistant steel; sealed mounting to refractory; flexible connections and manual shut-offs for maintenance
• Orifice plates and gas needle valves: Tailor-made sizes per combustion zone for optimized fuel efficiency