CS233995B1 - Aggressive Container! - Google Patents

Abstract

The invention relates to a container for an aggressive environment, in particular a pickling bath for acid with a temperature of around 90 °C, which must withstand temperature shocks during level fluctuations and when draining and filling the bath in frost and impacts of the pickling basket. The container consists of a shell (1) and an insert (2) with a built-in expansion layer (4). The essence of the invention lies in the fact that the intermediate space (3) is provided at the bottom with a pipe (5) for connection to the supply and discharge of a liquid, e.g. water, and in the upper part the intermediate space (3) is provided with an overflow pipe (6).

Description

¹ The invention relates to a container for aggressive environments, particularly for pickling acid baths having a temperature of around $ 0 ° C, must withstand thermal shocks and at the level fluctuations during filling and draining the bath for freezing and shock pickling baskets ·

For the staining of stainless steels, wooden tubs were used previously, but they cannot be made in the required dimensions of 5 to 7 m long, 1.5 to 2.5 m wide and about 1.5 m deep. Another well-known material is rubberized steel sheet, the lining however, it is not suitable for high concentrations of acids and mixtures thereof and for high temperatures near the boiling point, when it becomes brittle and is not puncture resistant® PVC-laminate, polypropylene-laminate and foamed polypropylene-laminate combines well below 50 ° C · In long-term operation with a pickling bath at a temperature higher than the second order liner transformation point, due to the thermal shock when the acid is released, it breaks away from the laminate, thereby ceasing to protect the laminate; Another variant of a polypropylene pickling pan, externally reinforced with a steel frame, places considerable demands on the maintenance of an acid-proof steel frame and the repair of a polypropylene bath that bursts due to a mismatch of the polypropylene's thermal expansion compared to steel and also due to corrosion of steel reinforcements ·

Significant progress has been made when the aforementioned plastic polypropylene-laminate plastic tub has been used as a sheath for the polypropylene foam insert, with an intermediate space having an expansion layer interposed between the jacket and the insert, for example foam polystyrene, foam rubber, etc. a wall dilatating in the direction of its length could be crushed at the periphery and supporting the liner in the direction of hydrostatic pressure and impact. The disadvantage of this solution is the diffusion of hydrogen chloride λ of nitrogen oxides into the expansion joint, where they accelerate the aging of the expansion layer and further up to the contact surface with the laminate, whose fibers break up. For these reasons there has been

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- 2 after two years at the point of the most frequent impact of the pickling basket into the liner to squeeze out the expansion layer, which ceased to fulfill its purpose and due to the extremely strong impact of the pickling basket, the liner was punctured, which had to be repaired ·

The aforesaid disadvantages are avoided by the container for an aggressive environment, in particular for the pickling environment, consisting of a sheath of composite plastic and a liner of chemically resistant plastic, with an intermediate space with an intermediate expansion layer formed between the sheath. at least one wall. The principle of the invention consists in the fact that the space between the jacket and the insert is provided at the bottom with a pipe for connection to the inlet or outlet of liquid, eg water, and in the upper part the space is provided with an overflow pipe.

The advantage of the aggressive environment vessel according to the invention is that while maintaining the possibility of expansion of the liner against the sheath, the hydrostatic pressure of the pickling bath is balanced over the entire surface of the liner by the hydrostatic pressure of water in the interspace. ensures that the diffusing aggressive vapors of the pickling bath components are neutralized by water hardness.

An exemplary embodiment of the device according to the invention is shown in the accompanying drawing, in FIG. 1 in cross-section and in FIG. 2 in a view of a wall with discharge tubes.

-J |

For pickling high-alloy steels in a 15% hydrochloric acid solution at a temperature of about 80 ° C, a pickling bath of 5.2 x x 2.5 x 1.5 m was used, which requires a resistance to impact of a basket of up to 3 tons. The sheath X was formed of reinforced plastics, i.e., a fiberglass with steel reinforcements and a polypropylene lining in which a liner & made of foamed polypropylene is inserted.

On the opposite and one of the adjacent walls to the wall with the outlet neck between the liner 2 and the liner of the sheath χ, an expansion layer 6 of sheets and foamed polypropylene shavings having a thickness greater than twice the thermal expansion of the liner 2 was glued. On the other walls, the polypropylene sheets of the liner of the casing χ were applied to the insert 2 with a manufacturing tolerance of the sheets, whose flatness usually does not deviate from a tolerance of -2 mm and after long-term operation. The outlet 2 of the liner 2 was sealed against the casing χ by means of a gland. .-3233 99S diny pickling bath. According to the operating instructions, water is filled into the interspace 2 after filling the liner 2 with a bath and drains the pickling bath before it is discharged.

Claims (1)

Container for an aggressive environment, in particular a pickling environment, consisting of a sheath of plastic and a liner of chemically resistant plastic, wherein an intermediate space is formed between the sheath and the insert with an expansion layer inserted at least along one wall. a pipe (5) for connection to the inlet and outlet of liquid, eg water, and in the upper part the interspace (3) is provided with an overflow pipe (6).