Gas kiln is a thermal equipment that uses natural gas, liquefied petroleum gas, gas and other combustible gases as the main fuel to fire ceramic products and refractory materials, generally referring to the "Shuttle kiln".

The gas kiln applied to modern ceramic production and creation originated in the United States in the 1950s, and the first gas kiln in China was the orbital kiln introduced by Jingdezhen Cosmos Porcelain Factory from Australia Bote Oken Kiln Company in the early 1990s, and then with the large amount of oil and natural gas exploitation and utilization, there was gradually a Chinese gas kiln.

In the 1960s, Peter Walker, a pioneer of modern ceramics, used gas kilns to fire his works in his studio

In 1975, the Italian shuttle gas kiln Pagnotta Termomeccanica company

In 1991, China's first shuttle gas kiln, imported from Australia, is now on display in Jingdezhen Tao Xichuan Industrial Heritage Museum

In 2020, the Italian production of railless power gas kiln, Pagnotta Termomeccanica company

After more than 30 years, gas kilns developed rapidly in China's ceramic production and manufacturing industry, and gradually replaced wood kilns and extended to modern pottery creation. Compared with wood kiln or coal kiln, gas kiln has low pollution, low fuel cost, controllable atmosphere and temperature, high firing temperature (above 1350℃), fast working efficiency and higher yield.

Gas kiln is intermittent inverted flame or semi-inverted flame kiln, according to the iterative order and operation mode can be divided into manual ignition kiln, semi-automatic kiln and fully automatic control kiln three kinds, compared with continuous kiln, intermittent kiln operation is more convenient, loading and unloading is more flexible, can meet the continuous production, but also suitable for small-scale spacing art creation.

2021, shuttle kiln in a public kiln in Jingdezhen

Shuttle kiln developed by Bai Tao Hui

The reason why it is called "shuttle kiln", because the main body is composed of two parts of the kiln chamber and kiln car, the ceramic body is placed on the kiln shed board, and the kiln chamber is fired through the track, and the kiln car and the finished product are pulled out of the kiln chamber after cooling. The kiln car operates like the shuttle of the ancient loom, and its push-pull mode is similar to that of a drawer, so it is also called "drawer kiln".

As mentioned above, gas kilns have experienced three stages of development in China: manual, semi-automatic and fully automatic. Advanced ceramics, industrial ceramics, sanitary ceramics and other industries have long had large automatic kilns. The art ceramics and living ceramics still stay in the manual era, due to the cumbersome production process, not easy to transport, so most of the manual gas kiln for manual construction, it is difficult to achieve standardization, safety performance can not be guaranteed.

Next, Baitao Jun takes you back to the development of gas kiln >>>

As the name suggests, manual gas kiln is a traditional gas kiln that is manually ignited and operated, and there are usually multiple groups of intake valves and Venturi self-priming burners at the bottom, with double rows and parallel distribution. The more burners, the higher the heating efficiency. After the ignition is successful, the flame enters the kiln chamber vertically through the hole, and enters the reduction stage after the oxygen in the kiln is naturally burned out. The size of the flame in the firing process depends on manual adjustment, and it is easy to cause a large temperature difference under the influence of human factors.

The firing of manual gas kiln is completely dependent on the technology and experience of the kiln master. According to the temperature specified during the firing period, they properly adjust the gas valve, air pressure, gate and damper to control the combustion value, kiln temperature and atmosphere. In order to achieve the ideal effect of stable heating and uniform combustion, it takes years of trial and error. Even if there is a manual guard during the whole firing process, the temperature cone (a tool to measure the actual temperature) is observed at a fixed point and time to reverse, the ram is closed in time after the end of oxidation, and the air pressure and gas transmission pipeline are stable, but the final effect cannot be guaranteed.

景德镇某陶瓷作坊内的气窑

The shuttle kiln is more than 4 meters high, and the highest fire viewing hole is more than 3 meters from the ground

The reason is that the gas pressure (flue gas and air) in the kiln plays a decisive role in the temperature and atmosphere, and the temperature and atmosphere are the key factors in the sintering of ceramic works.

The oxygen entering the kiln from the burner hole is partly sucked away by the flue, which is easy to produce negative pressure to interfere with the pressure in the kiln. If the negative pressure is too high, more oxygen will enter, the gas stratification is serious, the temperature difference between the upper and lower levels is large, and the reduction atmosphere is difficult to effectively maintain. The positive pressure is too high, a large number of hot gas overflow, high heat consumption and low heat efficiency, slow firing speed, and the billet can not be sintered.

The difficulty of firing, low safety factor, high requirements for the experience and ability of the kiln personnel, and low overall efficiency are the reasons why many ceramic training rooms in schools do not choose shuttle kiln.

Gas kiln ram regulation

Based on the bottleneck problems affecting the popularity of gas kiln, such as the complicated ceramic firing process, the high management requirements of firing training space, and the lack of professional firing workers, Baitao Hui has begun to explore the production process of gas kiln since 2016, and has conducted a lot of investigations and practices, and demonstrated while researching and developing.

We have carried out a series of improvements and upgrades to the traditional manual gas kiln, using standard steel plate, Morgan mullite, electronic burner, national standard galvanized pipe... The proportion of bricks exceeds refractory cotton, the appearance design is more novel, the first to launch the standard vaporizer, and a series of innovations have made the manual gas kiln a qualitative leap.

Baitaohui basic gas kiln firing experiment

Baitaohui self-developed basic gas kiln, Jingdezhen eight academy of fine arts joint base firing center

Baitaohui ceramist manual gas kiln, electronic ignition, safety upgrade

Building a kiln is just the beginning, building a good kiln is the goal!

Since June 2020, Baitao will join hands with a number of well-known thermal experts, professors, kiln construction and firing lines, engineers and designers proficient in control systems, opening the road to automated gas kiln research and development.

Hardware product development partner more than 200 days and nights, the first generation of independent movable gun power burner finally successfully tested in May 2021, and applied to the soda kiln, after adjusting the air pressure, a key ignition, with its own combustion fan and pressure adjustment device, the size of the fire is completely controllable.

Baitohui power burner 1.0

A burner is a device that causes fuel and air to spray a mixed (or mixed ejecting) horizontal flame in a certain manner. It is composed of shell, nozzle, flame stabilizer, gas pipeline and gas control system. The nozzle is the component that ejects the gas into the burner, and the flame stabilizer is responsible for keeping the flame from spreading and burning steadily. The control system controls the ratio of gas flow and air. The burner makes full use of the gas and improves the combustion efficiency.

Compared with the self-priming burner, the power burner gas premixes part of the air required for combustion, and the remaining air is directly directed to the flame. According to the principle of diffusion combustion, the oxygen in the secondary air continues to burn. The central reflux area formed by the rotation of the flame ejecting flow plays a role in stabilizing the flame and stirring, making the heating more uniform; Moreover, the kiln pressure is evenly distributed to prevent cold air inhalation; In addition, the flat flame is generally closer to the body than the straight flame, heating faster, greatly improving the firing efficiency and reducing the fuel cost.

Since June 2021, the R&D department of Baitaohui has continuously improved the power kiln for pottery teaching, and has carried out a lot of practices in burner design, gas leakage monitoring and protection, gas storage safety, and thermal insulation structure of the main body of the kiln. It has successively launched a number of power gas kilns, and has been applied in ceramic training rooms and artist studios in many universities. It has been widely recognized by professional users.

During the Jingdezhen International Ceramics Expo in 2022, Baitaohui Power gas Kiln was officially unveiled and received attention from the industry.

In summary, the combustion system design of the power gas kiln is more scientific, the flame length is controllable, and it is long enough to meet the needs of high temperature firing; Stable flame structure, gas and air mixing ratio is accurate, energy saving effect, greatly reducing the cost of use for users. The key point is that the burner is configured with ignition control, temperature control and pressure control, and the gas input is safe, effectively eliminating safety accidents.

Baitaohui power (semi-automatic) gas kiln

Recently, under the witness of the Ministry of Industry and Information Technology SME Development Promotion Center, Jingdezhen Municipal Government, Jiangxi Province SME Development Promotion Center and other government departments and Jingdezhen Art Vocational University leaders, the ceramic manufacturing training workshop of Jingdezhen Art Vocational University, which is provided with planning and design, optimized equipment and operation and maintenance services by Baitao Association, was successfully ignited.

The four automatic gas kilns for the ignition test were jointly developed by Baitao Association and Jingdezhen Ceramic University, which took 14 months to design, 3 months to build the main body, 42 days to lay the line, and 7 days to debug the function. Poured into dozens of experts, engineers and production line workers. The largest one has a volume of 4m³, and the total volume is about 9m³, which maximizes the demand for teaching, practical training and practice in ceramic vocational education.

Baitaohui automatic gas kiln, Jingdezhen Art Vocational University ceramic manufacturing training workshop

Yes, it really is fully automatic this time!

Automatic gas kiln firing in just four steps!! The first step, loading kiln; The second step, push the kiln car into the kiln chamber; Step three, press the ignition key; Step four, close the kiln door!

This is because it comes with a powerful "intelligent center" : fully automatic control terminal, gently press the ignition key, up to more than 70 neural lines will transmit this command seconds to the next server, igniter, flue gate, combustion fan, smoke exhaust fan, kiln pressure system... When instructed, move quickly and fire the task accurately.

Each gas kiln has an independent control station, the control terminal adopts MCGS touch screen, centralized interference control mode, through the signal line to connect the igniter, limiter, stepper motor, actuator, solenoid valve, gate valve, alarm system and other executive units, to form a super burning robot like "future soldier".

Just like the electric kiln, we set the temperature curve and firing process in advance, and according to the set curve, the system synchronously completes the preset kiln pressure, atmosphere, and gate valve opening time. After the ignition is complete, the regulator compares the feedback signal of the pressure transmitter with the set value, outputs the exhaust fan frequency and flue gas emission command, and realizes the kiln pressure stabilization.

With a sensitive and large control system, power burner, powerful combustion and smoke exhaust fan support, pottery gas kiln is truly fully automatic! The firing process requires no manual attendance, the fuel is maximized, and the temperature difference is controlled within single digits or even zero. After many tests, under the same fuel and the same specifications, the gas saving of the automatic gas kiln is more than 20% than that of the traditional gas kiln.

This is the first time that fully automatic program control technology has been applied to ceramic teaching kiln, marking that ceramic gas kiln has officially entered the intelligent era from the manual and semi-automatic era! Since then, the difficult gas kiln firing has become as easy as the electric kiln!

In order to realize the dream of "scientific pottery and efficient innovation", so that more schools and ceramic people can use safer and more intelligent kilns, in the future, Baitao will further optimize and improve the products of automatic gas kilns, and the four steps of kiln firing are expected to be simplified again, automatic kiln car entry and exit, waste gas recycling, automatic switch of kiln doors... Soon all will become a reality one by one, Baitao will walk hand in hand: exploration, non-stop!