Even Ovens For Daily‑life Use — Such As Roast‑duck Ovens, Pizza Ovens And Bread Kilns — Also Adopt Fire Bricks For Their Furnace Chambers.

Preface

For furnace chambers of roast‑duck ovens, pizza ovens and bread kilns, high‑alumina bricks or clay refractory bricks are preferred, thanks to their suitable working temperature and balanced thermal insulation performance. During masonry construction, attention shall be paid to the chamber curvature, joint sealing and thermal stability. It is recommended to simplify the installation based on the core principle of the support method.

 Suitable working temperature: The baking temperature inside the furnace chamber is approximately 200‑300 ℃. Bricks with refractoriness ≥1580 ℃ and cold‑crushing strength ≥20 MPa shall be selected. Both high‑alumina bricks (Al₂O₃ content: 60%‑80%) and clay refractory bricks (Al₂O₃ content: 30%‑45%) are applicable.

 Shape and dimension: Prioritize standard straight bricks supplemented with a small quantity of wedge bricks. The dimensional tolerance of bricks shall be ≤±2 mm to ensure good fitting during masonry. Large‑size bricks should be avoided. The single‑brick weight is recommended to be ≤5 kg for easy manual laying.

 Balanced thermal insulation and thermal conductivity: The bulk density of bricks shall be controlled within 2.0‑2.4 g/cm³. It ensures efficient heat conduction for fast temperature rise and reduces heat loss, so no extra thick insulating layer is required.

Recommended Adapted Solution: Simplified Support Method (Suitable for small‑size bread kilns with diameter mostly less than 2 m)

1,Foundation preparation: Clean the kiln steel plate (or red‑brick base), ensure the surface is flat and free of oil contamination, and snap reference lines according to the curvature of the furnace chamber.

2,Sectional Masonry：

 First lay the lower semicircle of the furnace chamber. Check the curvature after every 2‑3 brick courses. Fill brick joints with refractory mortar, and control joint width within 2‑3 mm.

 Support the laid brickwork with hardwood sleepers and simple jacking bars. Space the jacking bars at approximately 0.8‑1 m apart to prevent the brickwork from sliding down.

3,Kiln Rotation and Continued Masonry: Manually rotate the kiln body (or shift the working position). Resume masonry after each rotation of 45°‑60°, and progress upward step‑by‑step to the key‑brick opening.

4,Key‑brick treatment: Reserve a gap for 2‑3 bricks. Select well‑fitted key bricks and drive them in from the side, then wedge tight with 1‑2 mm thick steel plates to ensure the brick ring is firmly locked.

 Joint sealing: Fill all joints with high‑temperature refractory mortar (refractoriness ≥1600 ℃) throughout masonry. Voids and gaps are strictly prohibited to prevent flame leakage and heat loss during operation.

 Curvature control: Use an arc template for on‑site inspection during masonry to ensure smooth inner furnace wall without protrusions, so as not to disturb hot‑gas circulation and uniform heating of food materials.

 Thermal stability protection: Allow natural curing for 24‑48 hours after masonry. Perform gradual temperature rise for the first firing (from 100 ℃ to 300 ℃ at a heating rate of 50 ℃ per hour) to prevent brick cracking caused by thermal shock.

 Prohibited operations: Do not mix refractory bricks of different materials. Do not install bricks upside‑down (large‑small end reversed. Provide temporary support before key‑brick installation.