Tunnel Kiln Kiln Car FAQs (Basic Knowledge & Design and Material Selection)

Q1: Why is the kiln car considered the most critical and essential equipment in the tunnel kiln?

The kiln car is the most expensive and impactful auxiliary equipment in the tunnel kiln. It directly determines whether the kiln can operate continuously and stably, the quality of fired products, equipment failure rates, and overall energy consumption. The kiln walls and roof maintain constant temperatures with heat loss mainly from conduction, while the kiln car repeatedly enters and exits the high-temperature kiln, enduring severe thermal cycling. It is the primary source of heat loss, equipment failures, and production interruptions in the entire line.

Q2: What production problems can poor-quality kiln cars cause?

Inferior kiln cars easily lead to deformation, jerky movement, collision with kiln walls, slag accumulation on the track, and even collapse of the car itself. In severe cases, this forces the kiln to be shut down and the flame extinguished, interrupting continuous production, causing capacity losses, increased maintenance costs, higher reject rates, and significantly reducing the economic benefits of the production line.

Q1: What hidden risks arise from substandard steel material selection for kiln cars?

Some manufacturers use steel with negative dimensional tolerances and non‑compliant material properties. After commissioning, the kiln cars, subjected to long‑term stress and thermal cycling, undergo structural deformation, causing overall dimensional shifts. During operation, they rub against or collide with the walls, severely affecting the running precision inside the kiln.

Q2: What are the risks of non‑standard welding on the main beams and critical welds?

The main beams, secondary beams, and push‑car force points are core load‑bearing areas that require standard processes such as groove welding and fillet welding. If the manufacturer simplifies the welding procedure, the weld strength will be insufficient. After long‑term heavy‑load and high‑temperature operation, weld cracking and structural loosening may occur, and in extreme cases, kiln car collapse.

Q3: What are the hazards of skimpy welding on the bottom plate of the kiln car?

Large‑section kiln cars must have additional stiffening ribs, and the plates must be fully groove‑welded. If intermittent welding is used, heat will penetrate through the bottom, material will leak, and debris will fall and block the track inside the kiln, causing the kiln cars to run unevenly and jolt, thus affecting firing stability.

Q4: Why does the traditional welded structure of the sand seal plate often have problems, and how can it be improved?

When the sand seal plate is integrally welded to the main beam, the differential thermal expansion and contraction at high temperatures cause uneven stress, leading to deformation and jamming between the sand seal plate and the sand seal groove. The improved solution uses oval‑hole bolted movable connections, which allow self‑adjustment to thermal deformation, ensuring sealing effectiveness and smooth operation.