FR2489811A1 - REFRACTORY COATING FOR HEATING OVENS OR SIMILAR FURNACES - Google Patents

Abstract

THE INVENTION RELATES TO A REFRACTORY COATING FOR REHEATING OVENS OR SIMILAR OVENS. THIS COATING CONSISTS OF A CONSTRUCTIVE PLASTIC MASS WHICH, PNEUMATICALLY TREATED, HOMOGENOUSLY COMPRESSED, CONSOLIDATED BY CERAMIC AND IN THE FORM OF PELLETS, CONTAINING ALO IN A PROPORTION OF 25 TO 94 BY WEIGHT. APPLICATION IN PARTICULAR TO THE INTERNAL COATING OF METALLURGIC OVENS AND TANKS.

Description

The present invention relates to a coating

  one or more layers for heating ovens, such as blowing furnaces, moving sparers and pits, as well as metallurgical vessels, such as aluminum melting furnaces or

  casting ladles of pig iron and steel, said coating

  It is applied to the ceiling and / or on the side walls of furnaces which are thus subjected to high operating temperatures. The refractory linings of installations of this type are put in place in different ways. They are applied directly on the furnace wall, or on an intermediate layer or an insulating layer. In the first case, it is a single layer coating and in other cases, this coating comprises several layers. Depending on its structure or type, the refractory mass

  can be projected or compressed by shelling.

  For example, a projection is used when gunning, in which a concrete or

  hydraulically bound mass, in which case the quantity of water required

  is mixed only at the end of the nozzle. Until now,

  it is not yet possible to project plastic materials

  construction. These massive materials are delivered on site ready for use, in the form of blanks and, under

  this form they are applied behind a formwork corres-

  laying, then layered with a hammer

of damage.

  This treatment product has disadvantages

  technical and economic matters. On the one hand,

  the thickness of the layer of blanks, the degree of aggression

  Glomeration decreases continuously in the direction of shelling

  on the other hand, because of the application in layers and the pestle-

  subsequent sweeping of the blanks, a perpendicular

  culural direction to the direction of the shelling and the blanks indicated

  viduals do not sufficiently fit into each other.

others.

  Non-homogeneous agglomeration and interstices

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  formed after a short period of

  create weak points that are vulnerable to gaseous and liquid materials that not only significantly reduce longevity

  refractory coating but, moreover, provoke

  riorations of the envelope. Moreover, in this method of treatment, it is not always possible to avoid that the

  ceramic anchors introduced previously

  pneumatic or mechanical hammers, which leads to damage to larger areas of the ceiling and sidewalls. To these technical drawbacks are added the considerable costs resulting from assembly operations, complicated formwork

and set-up times.

  It is therefore an object of the present invention to overcome the aforementioned drawbacks, thereby increasing the service life of the refractory lining and

  by allowing a simple and inexpensive mounting of the latter.

  According to the essential characteristics of

  the invention uses building masses of

  ceramic-reinforced plastic material by pneumatic treatment

  the mass containing between 25% and 94% by weight

of Al20 3.

  According to the invention, instead of using tamping hammers, compressed air is used both for transporting the mass ready for use, and for applying and compressing this mass in a homogeneous manner and

  without bedding on its support surface until it has

ring the desired thickness.

  In order to project a plastic mass, there must be a harmonious relationship between the quantity of air,

  the working pressure and compression of this air, the

  the transport tubes used and the consistency of the

  material to be sprayed. When all these conditions are satisfied, a

  Optimally, such building masses are possible.

  Another advantage of the process according to the invention

  This is because ceramic anchor blocks, incorporated and blocked before the projection, do not

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  there is no risk of damage or mechanical overload caused by hand-guided hammers, so these blocks

  retain their function as retainers.

  From the economic point of view, the method according to the invention reduces by more than half the assembly time compared to known application methods, and it allows

  to save complicated forms.

EXAMPLE:

  Pneumatic lining using plastic building materials is carried out by means of a machine

  known in itself, in which case the plastic mass is

  in the form of granules. The transport and compression air is compressed air between 4 Nm 3 / min. and 18 Nm 3 min. according to the power supply, issued by

  a compressor with a compression pressure of at least

  mum 6 bars. The mass-to-air ratio is 1: 2 to 1: 4.

  feed bit or the nominal flow rate of the rotating machine

  is between 2 m / h and 6 m / h. According to the

  of the plastic mass, a nominal flow can be used.

  reduced, reaching from 2.3 t / h to 7 t / h.

  Depending on the flow rate used, flexible supply tubes having an internal diameter of 32 mm to 50 mm are used. Depending on the quantity dispensed and the size of the flexible tubes, the compressed air consumption is between 4 Nm 3 / min. and 18 Nm / min., resulting in the following data Nominal flow m / h 2 3 4 3 4.5 6 Amount of air Nm3 / min. 6 10 10 10 10 16 Internal diameter of flexible tubes in mm 32 50 50 50 50 50

  The diameter of the flexible tubes shown in

  above adapted to the power in question) relates to

  gate to the nominal power of the rotating machine. which is reached only in the presence of high building masses

fluidity.

  Compressed air at a pressure of 6 bar is practically available in sufficient quantity on all 248.981l yards. Advantageously, the plastic mass is applied by means of a rotary machine having a nominal flow rate

  of 4.5 m / h, in which an air flow of about 11 m / min.

  at 2.5 bar leaves the end of the flexible tube, this flexible tube having an internal diameter of 50 mm. The air required for the treatment of the building mass has a working pressure of 2 bar to 4

  bars, preferably 2.5 bars. The minimum pressure of com-

  Air pressure during mass treatment is 6 bar.

  As a result of the pneumatic treatment of the plastic building mass, the coating forms a layer without bedding and monolithic over a large area. Once the application

  completed, the surface of the plastic mass treated pneumatic-

  is roughened. Once the application is completed, this pneumatically treated plastic mass is pierced with

  evaporation holes. Said mass is applied pneumatically

  isolated areas on the ceiling and / or walls

side of the oven.

  It goes without saying that many modifications can be made to the refractory coating described and

  shown without departing from the scope of the invention.

Claims (9)

  1. Refractory lining with one or more   layers, intended for furnaces to be heated, furnaces with long   movable gerons and small ovens, as well as   tallurgy, such as aluminum smelting furnaces or   casting ladles of pig iron and steel, said coating   being applied to the ceiling and, possibly or   laughing, on the side walls of said furnaces intended to be thus subjected to high operating temperatures, coating characterized in that it consists of * a mass   construction plastic which, pneumatically treated,   homogeneously awarded, chemically bound by ceramics and in the form of granules, encloses   Al2 3 in a percentage of 25% to 94% by weight.   2. Refractory lining according to the claim   1, characterized in that the mass is treated with a quantity   of air corresponding to a weight: air ratio of between 1: 2 and 1: 4.   3. Refractory lining according to one of the   1 and 2, characterized in that the air required for the treatment of the mass has a working pressure of   2 bars at 4 bars, preferably 2.5 bars.   4. Refractory lining according to any one   claims 1 to 3, characterized in that,   during mass processing, compression pressure minimum air reaches 6 bar.   5. Refractory lining according to any one   than claims 1 to 4, characterized in that the 3 3   amount of air reached 4 Nm / min. at 18 Nm / min. during the treatment of the mass.   6. Refractory lining according to any one   claims 1 to 5, characterized in that,   as a result of the pneumatic treatment of the plastic mass of construction, this coating forms a monolithic layer on   a large area and does not include any bedding.   7. Refractory lining according to any one   than those claims 1 to 6, characterized in that   the surface of the pneumatically treated plastic mass is 24898 1 1   roughened after application.   8. Refractory lining according to any one   as in claims 1 to 7, characterized in that   evaporation holes are provided in the plastic mass   pneumatically, once its application is completed.   9. Refractory coating according to any one   claims 1 to 8, characterized by the fact that   the building composition is pneumatically applied in isolated areas to the ceiling and, optionally or alternatively, on the wall.