What is and what is a stove lining for?

The walls of the combustion chambers of furnaces of any type require additional protection, since they are constantly exposed to open fire. To prevent them from burning out, you need to create an additional facing layer using lining. The lining of the furnace is carried out in several available ways, taking into account the material from which the device for heating is made, and other factors.

Description of the process and purpose of the lining

Lining is the lining of the inner walls of chambers in stoves that are constantly in contact with a flame. It is necessary for brick oven units, which begin to burn and crumble due to moisture loss, as well as for metal stoves and solid fuel boilers. Partitions of furnaces made of steel and other metals are more susceptible to burning out, because of this, many manufacturers supplement them with fireclay or kaolin screens.

Lining is needed not only for household heating appliances, this technology is also used for large melting apparatus in the metallurgical industry, ladles, steam boilers and other equipment.

Lining the furnace furnace with fireclay bricks or other material helps to protect the walls from mechanical, chemical, thermal or physical damage. Additional coating helps to reduce heat loss, but for this you need to accurately calculate the thickness of the layer, otherwise the walls will not completely warm up. Too dense layers of lining reduce the efficiency of the furnace, since heat fluxes in such a situation will go outside through the chimney, and not remain inside the building.

Lining Embodiments

The procedure is carried out in different ways, the most suitable is chosen taking into account the material from which the stove or fireplace is made. Also, the choice is influenced by the time of laying the facing layer.

Facing the inside of the furnace with finished chamotte bricks

Fireclay materials are considered the most popular method for lining heating appliances. Chamotte is a special clay fired at a maximum temperature of up to 1500 degrees. After the heated natural material is crushed, then panels, bricks or dry mixtures are made from it. Buyers are more likely to choose fireclay materials because of their quality, effective use and affordable cost.

Installation of heat-reflecting screens

It is advisable to install screens that reflect thermal radiation on the walls of metal sauna stoves. When used in other types of furnace units, the low efficiency of the screens may mean that they were installed incorrectly. The generated heat will not completely warm up the walls and instead will start to go into the chimney, taking into account the modernization of the system.

Application of hewn stone from natural rocks

Stones from natural rocks belong to class A materials, most often sandstone, quartz or granite is used for facing.It is recommended to use them for lining fireplace inserts, not stoves, since these materials have a low level of thermal conductivity and crack under the influence of strong fire.

Using roll materials or plates

Special plates and roll materials are suitable for surfaces with low thermal conductivity. Lining of this type can be carried out during the construction of the furnace or in an already finished heating device.

Coating walls with special solutions or substances

Substances or solutions with increased resistance to fire are applied to the inner surfaces of the walls of furnace furnaces. These can be dry mixes, from which a fire-resistant mortar must be prepared, or a heat-resistant adhesive mass, also used for fireclay masonry and brick walls.

Glue and mortar

In addition to the quality and characteristics of materials, the effectiveness of the lining procedure is also influenced by their correct installation with the use of special substances.

Solution

Heat-resistant solutions form a monolithic thin layer on the walls of the furnace, which protects the working surface from the effects of flame. This monolith may require repair as it wears out. When working with a solution, you must follow the basic rules:

• Solutions are prepared from dry mixtures of corundum, mullite or chamotte type, which are diluted with water to a creamy consistency. The proportions of the components and the characteristics of the mixtures are usually indicated on the packaging.
• First, the solution layer is fired with a blowtorch or heated in an oven until a hard coating forms during firing.
• If the lining is carried out using fireclay bricks, the joint seams must be filled to the entire height of the masonry.

For 1 m3 of brickwork, at least 100 kg of ready-made mortar from any type of mixture is usually required.

Refractory adhesive

Refractory glue is considered to be the stronger component, it is sold in containers weighing from 2 to 50 kg and is most often used for lining. Before starting work, the container is opened and mixed until a homogeneous mass, after which it is applied to the surface, observing the basic rules:

• The glue mass is applied to the moistened surface with a spatula with a layer of no more than 3 mm.
• When glueing the entire cavity of the furnace with glue, the procedure is carried out in layers, observing intervals of 15 minutes after each application.
• To glue basalt cardboard to horizontal sections, the composition with glue is diluted with water by 15% no later than 12 hours before starting work.
• The consumption of glue is from 1 to 4 kg, depending on the structure of the surface to be processed and the thickness of the adhesive layer.

The glue mass solidifies completely at a temperature of more than 25 degrees within 24 hours, if temperatures are more than 90 degrees - after 6 hours.

Instructions depending on the material

It is better to entrust the lining of a standard or induction furnace to specialists, but with minimal skills, this procedure can be carried out independently, following the rules.

Brick oven

When lining the furnace chamber of a brick oven, the thermal expansion of the material is taken into account. Between the inner protective layer and the outer standard layer of masonry, a gap of 7-10 mm must be left or supplemented with a gasket made of kaolin, basalt or asbestos type cardboard.

Metal oven

The procedure for metal stoves is the same as for brick equipment. It must be borne in mind that there must be a gap between the metal wall and the material to compensate for the linear expansion. This space can be filled with basalt or kaolin slabs or asbestos sheets.

Solid fuel furnace

For solid fuel furnaces, it is advisable to carry out the lining in one of three available ways.Heavy lining is carried out for furnaces with weak shielding, with this method, the lining is made by masonry in two or three layers. In the case of lightweight lining, the masonry must be single-layer. There is also a variant of on-pipe lining, when the boiler pipes are coated with refractory glue from the outside.

Clay oven

Fire chambers in clay ovens are recommended to be lined with fireclay bricks or coated with plastic refractory materials, for example, mastic or aluminosilicate glue. After solidification, a layer of such material is a dense shell that protects the walls from overheating.

Fireclay brick

Lining with fireclay bricks is carried out by laying out the material in several rows with a slope and an edge with a shift of up to 1/2 of the length towards the block in the lower row up to the top of the combustion compartment. The upper plane is faced last, laying the bricks flat. It should be remembered that the lining layer and the main masonry of the walls must correspond to each other in the location of the vertical joints.