Merkle International, Inc.

9567 US Route 20 West, 61036 Galena, IL
Telephone +1 815 777-2100
Fax +1 815 777-2106


Hall map

glasstec 2016 hall map (Hall 13): stand A64

Fairground map

glasstec 2016 fairground map: Hall 13


Timothy Park

Lager/Material, Logistik, Transport

9567 Route 20 West
61036 Galena, IL, USA

+1 815 777-2100

+1 815 777-2106


Our range of products

Product categories

  • 01  Glass production/Production Technology
  • 01.04  Glass melting technology
  • 01.04.01  Batch charging technology

Batch charging technology

  • 01  Glass production/Production Technology
  • 01.05  Forming for flat glass
  • 01.05.01  Float glass technique

Float glass technique

  • 01  Glass production/Production Technology
  • 01.08  Equipment for glass fibre production
  • 01.08.01  Glass wool technology

Glass wool technology

Our products

Product category: Melting technology for tank furnaces

Strut-Air™ - A suspended refractory system to match the long-campaign furnace.

Once a furnace that could endure an entire decade of glassmaking was little more than a wish. Today, furnaces routinely operate through campaigns of 14-15 years.

The refractory spanning the charge opening can be the weak point of a good furnace. Feeder end wall designs that were good enough for yesterday's furnaces could deteriorate before the rest of today's furnace needs rebuilding.

Merkle's unique Strut-air refractory system is specifically designed to provide a feeder end wall that will both improve production efficiency and complement the long-campaign furnace.

Why Strut-Air®?
The doghouse on a modern glass melting furnace needs to be more than just an opening in the side of the furnace through which the batch is introduced. With Strut-Air walls, the doghouse becomes a dynamic part of the glass melting process.

The following features demonstrate the part played by Merkle's Strut-Air system in today's state-of-the-art furnaces:
Because there is a flat, sloped surface just above the glass, the melting process starts immediately, as the batch collects the radiant heat reflected from this surface. The design allows for various refractory materials to be used, depending on the type of glass being melted.
The main feature of the Strut-Air system is suspension of a simple refractory wall by a series of moveable, fabricated structural tubes. These tubes not only provide support but also carry cooling air directly to the tie-back and support castings.
The design is versatile. The walls have been constructed for doghouses as small as 1.2 meters and as large as 12.2 meters wide.
Installation is simple and accurate. Strut-Air requires as few as two parent refractory shapes, which simplifies installation and helps insure proper fit during assembly.
Cooling air in the Strut-Air system is pressurized, to prevent refractory "rat-holing" from the corrosive furnace atmosphere.
For smaller furnace/doghouse applications, the support steel can be fabricated as a single frame, which functions as both support and conduit for cooling air.
The design of the individual refractory shapes allows refractory expansion on this unitized steel frame.

What are the advantages of Strut-Air<sup<>® over the jack arch and other types of conventional construction?
With the Strut-Air system, various angles can be incorporated into the sloping toe. This opens up the doghouse and improves radiant and reflective heat transfer. Thus, the batch glazes more quickly, which reduces the carryover of batch dust into the checkers.
Because the Strut-Air tubes are included in the scope of supply, initial material costs for the Strut-Air system may be slightly more than those for jack or sprung arch construction. Labor costs, however, are generally less because the installation of the Strut-Air system is simpler.
When a furnace is rebuilt, the Strut-Air tubes are reused. Thus, for furnace rebuilds, the replacement of refractory, castings, insulation, and sheet metal is less costly than replacing large blocks of fused AZS material.

Add up all of the benefits--cost savings, the higher melting efficiency of the batch in the doghouse, and the reduced clogging of the checkers--and the
Strut-Air system is clearly superior to jack and sprung arch construction.

Insulated Strut-Air®: the perfect way to keep thermal energy under wraps.

Years ago, glass manufacturers issued Merkle a challenge:

Design an insulated Strut-Air system to reduce the amount of energy needed to produce each ton of glass.
After experiments with several different materials and thicknesses, Merkle learned that, for most feeder wall applications, 25mm of ceramic fiber board is the optimum amount of insulation. 25mm of ceramic fiber board can reduce heat loss by more than half, from 2350 to 1080 BTUs per square foot.

Since 1986, Merkle has been insulating Strut-Air walls with either 25 or 50 mm of insulation. As energy costs have increased the use of 50mm-thick insulation has become justifiable. Merkle has adopted this as our standard. Depending on current energy costs, Merkle`s Strut-Air insulation package can pay for itself in 9-18 months, and save more than 10 times its original cost over a 10-year campaign.

More Less

Product category: Melting technology for tank furnaces

Merkle Bay-0-Seal

The Merkle Bay-0-Seal is comprized of blocks of cast and fired sillimanite refractory assembled in a steel frame and suspended above the spout, covering the entrance to the tin bath. This design provides an excellent against atmosphere discharge from the tin bath.

The Bay-0-Seal can be raised and moved during spout changes. The Merkle Bay-0-Seal, with its unique design can usually be put back into service, where other solutions may not withstand thermal cycling.

Nitrogen can be introduced through the side or roof blocks of the Merkle Bay-0-Seal, for operational flexibility.

Merkle has been supplying Bay-0-Seal systems for over 30 years. Let our experience work for you. The Merkle Bay-0-Seal can both improve production efficiency and complement the long-campaign furnace. For more information on the Merkle Bay-0-Seal system, please contact us by telephone, fax, e-mail, or mail.

More Less

Product category: Melting technology for tank furnaces

MT Modu-Lok™ - an interlocking suspended refractory system for covers and curtains for glass furnaces.

The Modu-Lok system uses prefired refractory to provide a structure of uniform density. Hanger and filler brick have structural, load-bearing treads on two sides. Materials are chosen to suit the particular application, for example, fused AZS may be best suited for a doghouse curtain, whereas mulite refractory is chosen for a canal cover.

Often covers or curtains--many with complex configurations--are built with two parent shapes.

Horizontal covers, vertical curtains or combinations of the two can be made from the same base shapes.

There are 1/2" (12 mm) treads on both the hanger and filler bricks to "lock" the cover together.

Thermal Efficiency
The Modu-Lok® construction allows for insulated or non-insulated systems, depending on the requirements.

Metallic Support
The hanger bricks are suspended using metallic anchors, while the sides are held in place with metallic plates. Metallics are clear of insulation, which adds to service life. Metallics can be made as stampings or castings in materials to suit particular conditions.

MT Modu-Lok® Waist Covers
The Modu-Lok system has been used in waist area covers for over 3 decades. The Merkle waist covers can be moved so a stirrer or cooler can be inserted. The superior refractory used in Merkle waist covers permits some thermal cycling of the waist covers. Steel frames are supplied with the refractory and metallics. The steel frames are normally water cooled.

MT Modu-Lok® Waist Curtains
Waist curtains are an alternative to shadow walls to separate the melter from the refiner. As with all Modu-Lok® systems, the metallics and support steel are kept clear of, or a safe distance from, the heat of the furnace. As with the waist covers, water-cooled steel frames are supplied.

MT Modu-Lok® Canal Covers
Special structures made using MT Modu-Lok® shapes
Certain furnace designs call for special structures. The flexibiltiy of the MT Modu-Lok construction allows special shaped covers and curtains, such as donkey walls or complex crutch arches, to be constructed using the Merkle MT Modu-Lok refractory shapes. Merkle can provide a solution for almost any complicated design challenge.

Merkle has supplied over 500 covers and curtains for the glass industry since 1972. Let our experience and technical superiority work for you. Please contact us about your upcoming construction or rebuild or if you have any questions about the Merkle Modu-Lok® system.

More Less

Product category: Melting technology for tank furnaces

The Merkle Tin Bath Roof - the technological leader in tin bath roof construction.

Merkle continues to be the technological leader in tin bath roof design. The world's top producers in float glass consult with Merkle on new tin bath roof designs. Through cooperative relationships with these glass producers, Merkle International has taken the concept of the tin bath roof to the next level.

Float glass producers have many of the same basic requirements for the tin bath roof:
Producers want minimal glass defects from tin drip due to tin condensation in the roof.
Breakage of roof refractory pieces is unacceptable. This would cause defects and processing problems.
Assembly of the tin bath roof needs to be quick, without sacrificing the quality of the construction.
Metallic hanger fatigue in the entrance and exit lintels is unacceptable.
The bath roof must be a suspended refractory system to match the long-campaign furnace.
Electrical distribution problems, especially inside the bath roof casing, must be minimized.
Lost production time must be kept at a minimum.

With this in mind, Merkle has designed a bath roof to meet these requirements. The Merkle bath roof is a complete design, including refractory design, metallic hanger design, electrical distribution system, sidewall and casing designs. The Merkle Tin Bath Roof meets the tough demands of float glass producers:

Merkle uses refractory modules that are nominally 250mm x 500mm. This large module size reduces the number of joints that were in the early tin bath roofs. The reduced number of joints translates into reduced area for tin condensation and subsequent glass defects due to tin drip.
The wide Merkle module has more material in a typical heating element module than a narrower module would. This means that the wider module will be mechanically stronger. In fact, breakage at the element holes has never occured in a Merkle module.
Mechanically assembled Merkle modules aid in the ease of installation and replacement of a tin bath roof. The mechanically fastened modules will not separate like mortared modules can. This makes module removal for heating element replacement much easier while making the original installation quicker.
Merkle entrance and exit lintel blocks use support metallic pieces at the top of the blocks. This considerably reduces the temperature on the metallic. Merkle has never had a problem with a lintel block metallic hanger.
The Merkle roof uses a proprietary hanger system that positions the casting a safe distance from the hot face of the roof, while maintaining good heat loss characteristics. This hanger system means lower mechanical and thermal stress for the metallic hanger, which will result in extended service life.
Electrical distribution bars (bus bars) are oriented parallel to the glass flow, reducing both cable and bus bar lengths. This reduces potential for problems in long-campaign furnaces.
Merkle bath roofs are constructed with fewer different parts, which makes installation easier and faster.
Merkle offers two products that are used in conjunction with the tin bath roof.

Merkle supplies a Bay-0-Seal that mates to the entrance of the tin bath. The Bay-0-Seal provides an excellent seal. To read more about the Merkle Bay-0-Seal please see the Merkle Bay-0-Seal page.
Merkle has a unique dross box hood design. The dross box fits between the exit lintel and the cooling lehr.

More Less

Product category: Melting technology for tank furnaces

The Merkle™ Batch Charger: Batch Feeding Equipment for Glass Making

At Merkle Engineers, our primary goal is to provide the glass industry with the best in customized equipment. The Merkle Charger gives you a wider range of batch feed capabilities than ever before. We provide the charger that is best suited to your operation, carefully considering your installation and service requirements.  

...And Construction
Merkle builds chargers to suit your needs with the simplicity, durability and reliability you have come to expect from us. When complete, we run your machine through its shop trials. Only then is it ready for your inspection.

...On-Site Service at Installation
Merkle provides supervision for both installation and commissioning of your charger. Our representative will work with your personnel to reassemble the charger and set it up to suit your method of operation. A separate visit is made toward the end of furnace heat-up to position the charger and make final adjustments. Instruction in maintenance and operation is conducted during these visits.

...And During Production
We are always available to discuss or answer questions by telephone, FAX or e-mail. For those problems which require a site visit, arrangements will be made quickly. We also offer an extended maintenance agreement, which includes periodic inspection, assessment of the charger, and review with your maintenance personnel, covering the features, functions and maintenance of the charger.

PS3- Pneumatic Sand Seal System
Merkle's PS3 pneumatic sand seal system gets high marks from production and maintenance personnel. This sand seal works efficiently to prevent batch from escaping underneath the wiper bar, keeping the machine and the floor clean.

Merkle combines the very latest technology and materials available to create chargers that can be easily-adjusted to meet changing furnace and production requirements.

In A Few Minutes...Or Less:

Pan travel (stroke) can be adjusted with common tools to suit varying feed rates or blanket requirements.
Adjustments for pan angle and elevation can be made quickly during operation, using controls conveniently located on the charger.
Blanket thickness and profile are easily changed by adjusting the position of individual gates with a simple ratchet mechanism at the side of the charger.
Monitoring these adjustments is made easy by the convenient location of indicators for pan angle, pan elevation and gate positions. 

Designed for doghouse widths from 6-14 meters, our Twin/Coupled machine is comparable to having two independent, single pan machines coupled together. The Twin/Coupled charger allows you to pull one unit back if there is a batch plant malfunction (with insufficient batch for both units) or for parts replacement or maintenance. The remaining unit will continue to charge the furnace, minimizing furnace upset associated with a break in batch charging.

Machine Alignment
The two halves of a Twin/Coupled charger are mechanically connected to form a single, rigid assembly, simplifying alignment.

Synchronization of Pans
The mechanical coupling of charger halves guarantees pan synchronization. If desired, the operator can disconnect the center coupling to operate pans independently, or pans can be operated up to 180 degrees out of phase relative to each other.

Auxiliary Drive on Standby
Two motor/speed reducer assemblies service an entire charging system, normally with only one in operation at a time. Consequently, the remaining drive is on the line as a spare without altering the charger position. Drive changeover can be accomplished in minutes.

Electrical Installation
Only two motors require electrical connection to the facility, and synchronizers are not required.


The newest in our line of state-of-the-art blanket batch chargers offers impressive solutions to many of your charging challenges. A small version of our Single Pan machine, the modular charger can be made in widths from 1-2 meters, to be used for very small furnace openings, or in sets to accommodate any doghouse application.

Easier Handling
Manageable modules move into and out of position more easily than with the larger machines.

Programming of Batch Distribution
With an electronic synchronizer, multiple units can be configured to produce feed profiles unavailable with wider units. Pan separations of 25mm give the modular unit the ability to retain batch log formation that is otherwise available only on larger machines.

Lower Impact of Inactive Machine
Each unit is small so that removal of one module from service has temporary minor impact on profile and negligible effect on batch feed rate.

As part of our continued commitment to customizing our product for your needs, Merkle is pleased to offer a variety of equipment options, including AC or DC motors, controllers, air or water cooling on pan and pusher bar, center-cooler mounting provisions, stairs, ladders, a variety of clutches or couplings, and tractive devices for positioning the unit.

Increasingly conscious of keeping the doghouse area clean, many glassmakers choose the Doghouse Enclosure to close off the space between the Charger and the Strut-Air backwall. The Enclosure is commonly constructed with an air-cooled platform on which personnel may stand for inspection of the backwall or the charger. The enclosure, typically built in two sections, is suspended from a trolley mechanism for easy removal as needed. Fewer attachment points means an easy installation.

More Less

About us

Company details

Merkle International, Inc. is the world's leading supplier of suspended refractory systems and related furnace equipment.  Merkle supplies suspended backwalls, tin bath roofs, and other furnace components as well as blanket batch chargers.

More Less

Company data



Area of business

Glass manufacture / Production technology

Target groups

Flat Glass

Company information as a PDF file