The Masonry Of A Float Glass Kiln Must Focus On These 5 Key Parts!

The masonry quality of a float glass melting kiln directly impacts the kiln's service life and production operations. When masoning the kiln, except for positions requiring dry masonry, refractory bricks should be laid with corresponding refractory mortar. Expansion joints must be set according to the expansion coefficient of the refractory bricks, calculated precisely during masonry.

Masonry of the float glass kiln is guided by the kiln's longitudinal centerline, the centerline of No. 1 small furnace, and the elevation. Below is a brief description of the masonry requirements for each part.

① The flue of a float glass kiln is generally masoned in the first stage of kiln construction, but some manufacturers, to meet ignition deadlines, build the main body of the kiln first and then mason the flue. In such cases, construction protection must be prioritized.

② Flue construction uses the centerline of No. 1 small furnace and the kiln centerline as references. For convenience, heat-resistant concrete can be used for casting at the junction of the main flue and branch flues, as well as for arch treatment at branch flue corners.

③ At the junction of flue arches with different spans, arches are constructed with straight joints, and walls with staggered joints. Here, ensure that arch bricks at the arch crown are no shorter than 120mm to prevent crown brick dislodgement.

④ Expansion joints in the flue wall should be sectioned: generally, set 8mm joints every 2m. Joints must be masoned with staggered joints, using clay bricks (insulating bricks are prohibited).

⑤ The outermost layer of the flue wall is red brick. Since red bricks differ in thickness from standard refractory bricks, masonry may mismatch. Thus, every 7-8 layers of red bricks should include a half-brick bite into the wall, adjusted by processing insulating bricks to match the biting height.

① The heat storage room wall typically has a thickness of 578mm: the side and end walls consist of one-and-a-half refractory bricks and one insulating brick, with expansion joints sectioned during masonry. The partition wall is fully composed of two-and-a-half refractory bricks, requiring expansion joints at both ends.

② The furnace strip arch is a critical component of the heat storage room, demanding strict safety measures: it must be aligned with a guiding line to prevent skew. Arch bricks are levelled with shim bricks, whose surfaces should be as flat as possible to facilitate lattice brick laying. Levelling the furnace strip arch for float glass kilns requires meticulous work due to its long operational life. The most common method currently is processing the lower surface of bricks to fit mortar masonry. After masonry, a reference line is snapped according to the arch's required elevation. Shim bricks are numbered, removed, cut to the marked line, and remasoned with mortar. Height adjustments are made using an angle grinder to match the elevation line.

③ After the back side wall of the heat storage room is built to the height of the small furnace bottom plate, it should be suspended to construct the chest wall and small furnace. Masonry of the back side wall can only resume after the small furnace skew arch and back flat arch are completed.

④ Lattice bricks must be laid vertically and horizontally. After production inspection, they should be packaged in boxes according to positive/negative tolerance classifications, with tolerance ranges marked on the boxes. For each layer, lattice bricks within the same tolerance range must be used during laying.

Bricks for the float glass kiln's pool wall are generally single-layered in the height direction and laid according to the numbered sequence specified in the drawings. To ensure the levelness and verticality of the wall bricks, small amounts of zirconium ramming material can be used as padding under the pool wall for adjustment.

① Adjust the chest wall pallets to the same level and fix them to the supporting iron. Determine the position of hook bricks based on the kiln's centerline, then snap a line on top of the pool wall bricks. At this stage, also mark the centerline of each small furnace, and number each brick according to its position as indicated in the drawings.

② After masoning the flat arch of the small furnace, the arch formwork at the end of the arch must not be removed immediately. It can only be removed after the adjacent chest wall sections are fully masoned and the jacks at both ends are securely fastened to prevent the flat arch from sinking.

③ All electrofused zirconium corundum bricks in the chest wall area are dry-laid. Notably, wooden wedges must be placed between the wall bricks and hook bricks to ensure the hook bricks remain level during laying.

④Given that the bricks in the chest wall area are large and heavy-some weighing several hundred kilograms-special attention must be paid to safety during construction.

① The float glass melting kiln adopts a steel arch support structure. Steel arch supports must be positioned accurately and stably. Along the length of the kiln on the same side, use steel wires to align the inclined surfaces of the steel arch supports in the same plane. If necessary, thin steel plates can be used as shims, ensuring sufficient contact area and stability of the shimmed supports.

② Supporting the arch formwork: Since the arch bricks of float glass kilns are generally 400-500mm thick and heavy, the arch formwork must have sufficient strength and overall stability. After installing the formwork, repeatedly measure and adjust it with a level to ensure it is uniformly level.

③ Before laying the arch, dry-lay 2-3 rings of arch bricks for each arch section to determine the size of mortar joints during formal masonry.

④ The key bricks of the main arch should be positioned 100-150mm above the arch crown. All key bricks for the same main arch must be driven in simultaneously to ensure even force distribution across the entire arch.

⑤ Silica mortar has poor workability, and main arch bricks are large. To apply mortar quickly and evenly on brick surfaces, silica mortar requires adequate mixing time and 4 hours of aging from mixing to use. Therefore, larger mortar pools and advance material preparation are necessary.

⑥ During masonry and kiln baking, strict control of the top head joints of arch bricks is required, with meticulous sealing using insulating materials. Each arch section's end is a free end with no constraints; poorly sealed expansion joints may leak fire. Thus, masonry at arch ends must be tight, and tie bars must be securely fastened. Additionally, stepped expansion joints at arch ends are recommended for better performance. After kiln completion, seal these joints with silica hot-patching material.

⑦ The main arch of a float glass melting kiln is long, so tension bars must be tightened incrementally. To ensure synchronous lifting of the main arch, install three measuring points along the length of each arch section. Use a level to monitor these points while tightening, ensuring uniform lifting across the entire arch. Typically, when the main arch rises 10mm, it separates from the formwork, allowing tie bars to be locked and formwork removed.

Masonry for the pool bottom, small furnace skew arches, and similar components is generally consistent with other industrial kilns. However, it is critical to note that refractory materials for most small furnace components are electrofused AZS bricks, which have complex shapes and are challenging to install. To ensure masonry quality, these refractory bricks must undergo precise grinding, pre-arrangement, and numbering to reduce installation difficulty.

For L-shaped hanging wall installation-whether imported or domestic-supplier technicians and design engineers should provide on-site guidance during construction and installation.