History/Timeline

The history of Morgan Crucible Company has been well documented, but little has been written about their furnace division. This key division of Morgan has been making furnaces for more than a century and has been a major contributor in ‘state of the art’ metal melting and delivery systems. This article gives a summary of the manufacturing history of Morgan Molten Metal Systems’ furnaces.

1800s
Furnaces for crucible melting were relatively crude in the late 1800s when Morgan started making their crucibles. Up until this time, getting more than one melt from a clay crucible was unusual and imported graphite types were only marginally better. This being the case, furnace design was not that important; its objective being only to reach the desired temperature as quickly as possible. Furnaces of this era were fuelled by charcoal or coke, arranged in a pit and supplied with air from types of bellows. The crucible would be located in a bed of carbonaceous fuel and heated in the same manner as a forge. When the metal was at the required temperature for casting, it would be lifted with tongs and its contents poured directly into the mold.

In 1856, Morgan began manufacturing the “extruded” plumbago crucible. It quickly became an established crucible and its ability to withstand a high number of melts left people looking to the furnace as a way to influence the life of the crucible. Morgan saw the importance of the relationship between the crucible and the furnace and looked to local furnace manufacturers to apply important design aspects.

Ultimately, this alliance proved inadequate and Morgan created their own manufacturing facility at Battersea at the turn of the 20th century. This was the start of what would become more than 100 years of furnace design and manufacture at Morgan.

The unique marriage of crucible and furnace has played a major role in the success of the business.

1900s
The early years of the 20th century saw the coke-fired furnace becoming highly refined, with ‘central axis’ and ‘lip axis’ pouring added to the established ‘lift out’ furnaces.

Morgan was at the forefront with the commercial production of the carbon brush. It was of no surprise that they saw the potential for this energy source in the process of metal melting.

In 1919, Morgan patented electric resistance crucible furnaces, the ES and the EA. These were very advanced tilting furnaces, some hydraulic, using the crucible as the resistance element and were capable of melting metals to 1200c and above.

For melting metals quickly, particularly to high temperatures, furnaces still needed ‘coke’ as a fuel. However, with the increasing availability of oil, a gradual change to this type of firing occurred. Morgan designed and developed its own manual oil burner in forms to suit both static and tilting furnaces. These were so good that they would be without rival for the best part of a century, capable of melting anything up to and including iron to 1450c.

The diversification of Morgan into associated refractories assisted furnace manufacturing. A wide range of lining materials, of which a large number were ‘fired’ shapes, were unique to Morgan furnaces.

The capability of manufacturing such precise shapes led to the development of electric resistance heater panels. These were done in Silliminite, which formed the support structures for nickel/chrome wire elements and were used in aluminum holding furnaces.

During and after World War II, the demand for high quality aluminum castings rose quickly and justified the separation of the ‘melting’ operation from that of the ‘holding’ operation. This created the demand for efficient ‘holding’ furnaces using electricity. The Electric Resistance Bale Out (ERBO) was developed shortly after. Hydraulic tilting versions (ERBT) based on spouted basin crucibles, came after.

With such furnaces, some form of automatic temperature control was needed and pyrometer systems were developed using thermocouples, clay graphite sheaths, and galvanometer controllers. This was a development that led to a range of consumable products that would endure for more than half a century.

By this time the furnace business had grown to such an extent, that it justified its autonomy as a company within the Morgan group and Morganite Thermal Designs was duly registered.

The company grew by developing new products and by the acquisition of other furnace and foundry product companies. Licensing agreements were also set up with producers of other important foundry products such as autoladles, dosing furnaces, ingot machines and foundry chemicals. After the acquisition of Felcoil Burners Ltd., Morgan Thermal Designs produced their own burners for furnaces and other equipment.

Another license from a company that developed a unique gas burner, took the business into more diversification. The ‘Blu Surf ’ burner had unique combustion properties, lending itself to a wide range of heating applications. While having some technical merit, the burner was not successful on high temperature applications, but out of it grew another unique furnace to Morgan -- ‘the immersed crucible furnace’. This design for melting and holding aluminum reversed the convention of the crucible being a metal container and made it into an immersion heater with metal on the outside.

So it was that the original Blu Surf burner gave way to the reliable Morgan Intimix burner. This burner was able to retain the essential properties of firing down into the crucible but was able to withstand the rigors of foundry application.

During the 1970s towns gas was replaced by natural gas and burner technology had to adapt to the different properties. This created both challenges and opportunities as Morgan was now effectively in the ‘burner business’. The changeover was carried out very effectively.

At this time Morgan Thermal Designs was able to supply furnaces to meet almost all applications, however one area was still not yet in the portfolio -- ‘electric induction melting’. During the late 1970s Morgan started creating a range of crucible based coreless induction furnaces. The development maximized the overall melting efficiency by optimizing the match between power to metal and that to the crucible. This saw the development of a medium frequency ‘push up’ furnace with a specially formulated ‘Indux’ crucible. At 1000 Hz, this gave the ratio of ~70% power to the metal and the remaining to the crucible, thereby optimizing melting efficiency, minimizing metal turbulence and retaining temperature while pouring.

Both the push up and larger tilting furnaces were subsequently supplied together with the Morgan parallel inverter. This effective unit was developed from the Enercon design acquired through the purchase of APV Parallec. The supplied packages included: Furnace, Inverter, Water Cooling System, Control Unit and all interconnections. Many of these units, supplied during the 1980s, still operate today.

Stimulated by the fuel crisis of the time, a range of recuperated furnaces became part of the offering. These set new levels of energy efficiency meeting the demand of foundries hit by energy rationing. All the popular sizes of aluminum bale out furnace were available in the recuperative design and sported the Morgan designed exhaust recuperator, capable of raising the combustion air to 250 degrees centigrade.

In the 1970s, the availability of a new type of element wire (FeCrAl) led to the development of a new range of ERBO and ERBT furnaces that would now have a realistic melting performance. The earlier Silliminite support system would not be suitable and a new approach was needed. The outcome was the now ‘industry standard’ semi embedded vertical element panel.

In the early 1980s, Morgan Thermal Designs dissolved and the furnace business returned back to a department of the larger crucible business.

The early 1990s saw the creation of the ‘Dual Energy Furnace’. Gas offered the best energy source for melting and electricity had advantages in accurate holding of aluminum at temperature. Bringing these two energy sources together in one furnace so that the most appropriate energy source was automatically selected became important and the Dual Energy furnace was created. These furnaces became available in all of the popular bale out sizes and tilting versions were also produced. Over 150 of these patented furnaces have been supplied to date, many of which have been exported around the world.

2000s
The new millennium saw the extension of the gas radiant panels developed in the Dual Energy furnace. This formed two advanced gas fired furnaces: the MkIV gas bale out and the MkV BT. range of bulk melters. A trio of crucible furnaces using the same crucible (either gas, electric or gas/electric), were now available.

Furnaces continued to increase in capacity. The popular ‘bale out’ furnaces of 50 years previous had capacities of 135 to 500Kg of aluminium and tilting bulk melters up to 700kg. Today our ‘bale outs’ go up to 2500kg and ‘tilters’ up to 1500kg.

Morgan’s furnace business retains its position as the ‘innovator’ in the field of crucible furnace design and exports 60 – 70% of the furnaces produced. High quality, high thermal efficiency and high reliability remain the key attributes of Morgan furnaces in the
21st century.