GB2111084A

GB2111084A - Strip pickling tank

Info

Publication number: GB2111084A
Application number: GB08233791A
Authority: GB
Inventors: Bernhard Schweinsberg
Original assignee: Dr C Otto and Co GmbH
Current assignee: Dr C Otto and Co GmbH
Priority date: 1981-12-11
Filing date: 1982-11-26
Publication date: 1983-06-29
Also published as: IT8249450A0; IT1148644B; BE895309A; DE3149086A1; GB2111084B

Abstract

In a tank for pickling strip, said tank being filled with pickling liquid and the strip being drawn longitudinally therethrough, the base, which consists of acid-resistant ceramic material, is provided with transversely extending slide ribs (1) which extend practically as far as the side walls of the tank. The slide ribs, the front edges (5) of which are not higher than the level of the base lining (7), have a parabolically asymptotically extending surface (3) with a portion extending parallel to the strip. The slide ribs advantageously consist of Ruhr hard sandstone, have a width of about 400 mm and are spaced about 3 000 mm apart. <IMAGE>

Description

SPECIFICATION Strip pickling tank This invention relates to a strip pickling tank for containing pickling liquid and through which the strip can be drawn longitudinally.

Tanks of this kind are generally provided with a base lining formed from acid-resistant ceramic bricks. It is known to provide the base or base lining of the tank with transversely extending projections at specific intervals in order to prevent the moving strip from damaging the base lining. Such damage is inevitable because the edges of the strip are uneven and projecting corners occur at the places where two strips of different widths have been welded together; when the strip is drawn through the tank the sharp edges of these projections slide over the lining and result in quite considerable damage. This disadvantage is not adequately avoided by the above-described transversely extending projections consisting of wearing bricks.

The object of this invention is to reduce or even practically completely obviate any contact between the strip and the base lining of the pickling tank and hence the accompanying damage. In addition tanks according to the invention may produce an intensive movement of the liquid interface with the underside of the strip in order to increase the pickling liquid exchange.

From one aspect the invention consists in a strip pickling tank for containing pickling liquid and through which the strip can be drawn longitudinally, the tank base consisting of acid-resistant ceramic material and having transversely extending projections at specific intervals, each transversely extending projections consisting of a slide rib which extends practically as far as the side walls of the tank and has a paraboiically asymptotically extending surface with a portion extending parallel to the strip, the front edges of the slide ribs as considered in the direction of strip movement being not higher than the level of the base lining.

Preferably the slide ribs consist of a brick material containing no sharp inclusions so that the surface is as smooth as possible. The use of Ruhr hard sandstone for the slide ribs has proved particularly suitable.

From another aspect the invention consists in a strip pickling tank for containing pickling liquid and through which a strip can be drawn longitudinally. wherein the base of the tank consists of acid-resistant material and having a plurality of transversely extending projections spaced along the tank, each projection having an inclined surface rising from the level of the base in the direction of movement of the strip.

From a still further aspect the invention consists in a strip pickling tank for containing pickling liquid and through which a strip can be drawn longitudinally, wherein the base consists of acid-resistant material and having a plurality of transversely extending projections along the tank, each projection having an upper surface profiled such that the pickling liquid forms a hydrodynamic wedge between the projection and the strip.

The invention may be performed in various ways and specific embodiments will now be described with reference to the accompanying drawings in which: Figure 1 is a plan view of the base of a portion of a pickling tank, and Figure 2 is a side elevation in partial section through the tank base and the base lining.

The pickling tank consists conventionally of side walls 2 and base 6, which is provided with an acid-resistant lining 7 of ceramic material, made up of two brick courses. The direction of movement of the strip 4 is denoted by an arrow in Fig. 2.

In this embodiment of the invention, the top course of bricks of the base lining is replaced, at intervals b of about 3,000 mm, by a slide in the form of a rib 1, which extends transversely of the direction of movement of the strip practically as far as the side walls 2 of the tank. The ribs preferably consist of Ruhr hard sandstone, which has very good sliding properties and adequate strength and no sharp-edged inclusions. The width a of the slide ribs in the example illustrated is about 400 mm. The surface 3 of the slide ribs rises parabolically in the direction of movement of the strip, the front edge 5 being somewhat lower than the surface of the top course of bricks of the lining, whilst the rear portions of the slide ribs extend generally parallel to the strip 4 and are slightly higher than the surface of the lining.It will be seen that the surface 3 is generally asymptotic to the strip or belt 4 before it passes in to the parallel rear portion.

As a result of the flow configuration caused by the slide ribs, the acid supply at the underside of the strip is increased. Also, the formation of a hydrodynamic wedge causes the strip to float slightly when it is drawn through the bath. An intensive liquid exchange is also achieved in the region of the strip surface. There is no damage to the base lining resulting from changes in strip width.

It has been found advantageous for the base of the pickling tank to be slightly inclined towards the exit end of the appropriate chamber in order to enable the pickling liquid to be completely drained and emptied.

Advantageously the ribs may be between 250 and 450 mm and their spacing may be between 2,500 and 3,500 mm.

1. A strip pickling tank for containing pickling liquid and through which the strip can be drawn longitudinally, the tank base

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Strip pickling tank This invention relates to a strip pickling tank for containing pickling liquid and through which the strip can be drawn longitudinally. Tanks of this kind are generally provided with a base lining formed from acid-resistant ceramic bricks. It is known to provide the base or base lining of the tank with transversely extending projections at specific intervals in order to prevent the moving strip from damaging the base lining. Such damage is inevitable because the edges of the strip are uneven and projecting corners occur at the places where two strips of different widths have been welded together; when the strip is drawn through the tank the sharp edges of these projections slide over the lining and result in quite considerable damage. This disadvantage is not adequately avoided by the above-described transversely extending projections consisting of wearing bricks. The object of this invention is to reduce or even practically completely obviate any contact between the strip and the base lining of the pickling tank and hence the accompanying damage. In addition tanks according to the invention may produce an intensive movement of the liquid interface with the underside of the strip in order to increase the pickling liquid exchange. From one aspect the invention consists in a strip pickling tank for containing pickling liquid and through which the strip can be drawn longitudinally, the tank base consisting of acid-resistant ceramic material and having transversely extending projections at specific intervals, each transversely extending projections consisting of a slide rib which extends practically as far as the side walls of the tank and has a paraboiically asymptotically extending surface with a portion extending parallel to the strip, the front edges of the slide ribs as considered in the direction of strip movement being not higher than the level of the base lining. Preferably the slide ribs consist of a brick material containing no sharp inclusions so that the surface is as smooth as possible. The use of Ruhr hard sandstone for the slide ribs has proved particularly suitable. From another aspect the invention consists in a strip pickling tank for containing pickling liquid and through which a strip can be drawn longitudinally. wherein the base of the tank consists of acid-resistant material and having a plurality of transversely extending projections spaced along the tank, each projection having an inclined surface rising from the level of the base in the direction of movement of the strip. From a still further aspect the invention consists in a strip pickling tank for containing pickling liquid and through which a strip can be drawn longitudinally, wherein the base consists of acid-resistant material and having a plurality of transversely extending projections along the tank, each projection having an upper surface profiled such that the pickling liquid forms a hydrodynamic wedge between the projection and the strip. The invention may be performed in various ways and specific embodiments will now be described with reference to the accompanying drawings in which: Figure 1 is a plan view of the base of a portion of a pickling tank, and Figure 2 is a side elevation in partial section through the tank base and the base lining. The pickling tank consists conventionally of side walls 2 and base 6, which is provided with an acid-resistant lining 7 of ceramic material, made up of two brick courses. The direction of movement of the strip 4 is denoted by an arrow in Fig. 2. In this embodiment of the invention, the top course of bricks of the base lining is replaced, at intervals b of about 3,000 mm, by a slide in the form of a rib 1, which extends transversely of the direction of movement of the strip practically as far as the side walls 2 of the tank. The ribs preferably consist of Ruhr hard sandstone, which has very good sliding properties and adequate strength and no sharp-edged inclusions. The width a of the slide ribs in the example illustrated is about 400 mm. The surface 3 of the slide ribs rises parabolically in the direction of movement of the strip, the front edge 5 being somewhat lower than the surface of the top course of bricks of the lining, whilst the rear portions of the slide ribs extend generally parallel to the strip 4 and are slightly higher than the surface of the lining.It will be seen that the surface 3 is generally asymptotic to the strip or belt 4 before it passes in to the parallel rear portion. As a result of the flow configuration caused by the slide ribs, the acid supply at the underside of the strip is increased. Also, the formation of a hydrodynamic wedge causes the strip to float slightly when it is drawn through the bath. An intensive liquid exchange is also achieved in the region of the strip surface. There is no damage to the base lining resulting from changes in strip width. It has been found advantageous for the base of the pickling tank to be slightly inclined towards the exit end of the appropriate chamber in order to enable the pickling liquid to be completely drained and emptied. Advantageously the ribs may be between 250 and 450 mm and their spacing may be between 2,500 and 3,500 mm. CLAIMS

1. A strip pickling tank for containing pickling liquid and through which the strip can be drawn longitudinally, the tank base consisting of acid-resistant ceramic material and having transversely extending projections at specific intervals, each transversely extending projections consisting of a slide rib which extends practically as far as the side walls of the tank and has a parabolically asymptotically extending surface with a portion extending parallel to the strip, the front edges of the slide ribs as considered in the direction of strip movement being not higher than the level of the base lining.

2. A tank as claimed in claim 1, wherein the slide ribs consist of a brick material having no sharp-edges inclusions or the like.

3. A tank as claimed in claim 1 or claim 2, wherein the slide ribs consist of Ruhr hard sandstone.

4. A tank as claimed in any one of claims 1 to 3, wherein the width of the slide ribs is of the order of 400 mm and the slide ribs are disposed at intervals of about 3 000 mm.

5. A tank as claimed in any one of the preceding claims, wherein the ceramic material is constituted by ceramic bricks.

6. A strip pickling tank for containing pickling liquid and through which a strip can be drawn longitudinally, wherein the base of the tank consists of acid-resistant material and having a plurality of transversely extending projections spaced along the tank, each projection having an inclined surface rising from the level of the base in the direction of movement of the strip.

7. A tank as claimed in claim 6, wherein the surface is at least partially curved.

8. A tank as claimed in claim 4 or claim 6, wherein the portion of the surface extends parallel to the plane.

9. A strip pickling tank for containing pickling liquid and through which a strip can be drawn longitudinally, wherein the base consists of acid-resistant material and having a plurality of transversely extending projections along the tank, each projection having an upper surface profiled such that the pickling liquid forms a hydrodynamic wedge between the projection and the strip.

1 0. A strip pickling tank substantially as hereinbefore defined with reference to the accompanying drawings.

11. A strip pickled in a tank as claimed in any one of the preceding claims.