DE2645669A1 - Sieve with a hinged base - for the rapid removal of sludge from molten salt, esp. from a nitriding bath - Google Patents

Abstract

Device for removing sludge from molten salts, esp. from nitriding baths comprises a container with a cross-section similar to the cross-section of the bath or tank which is lowered into the latter. The lower part of the container and its base are fitted with sieves; and the base is mounted on a hinge so it can swivel upwards. The parts of the container fitted with sieves are pref. replaceable. Used esp. in the nitriding of steel parts, where the sludge consists of iron nitride which impairs the efficiency of the bath. The sieve is easy to use and does not need to be left in the bath. It rapidly removes even very fine sludge.

Description

Device for desludging of molten salts, in particular

Nitriding baths molten salts for treating steel parts, in particular Nitriding baths separate sludge when in use, and in the case of the latter essentially consists of iron nitride.

Experience has shown that this sludge has a disadvantageous effect on the nitriding effect of the bath because it is able to increase the content of soluble Na4 (Fe (CN) 6). This increased iron content can then lead to porous connecting layers.

In addition, there can be sludge deposits on the bottom of the bath tank lead to heat build-up and damage to the bath tank.

So far, attempts have been made to desludge such baths with a trowel or by heating the bath to temperatures above the nitriding temperature, wherein the mud rises and can be skimmed off.

The first method is inconvenient and uncomfortable for the operator does not lead to success with deep bath tanks. The second method is time consuming, because heating up and cooling down large baths can take hours and more requires considerable heating energy consumption. Also the thermal load of the bath tank at high temperatures is disadvantageous and reduced necessarily the service life of the container, especially one used for nitriding, for example Bath tank with titanium coating.

There are also devices known to defoam salt baths by you hang a Schlanim pan in which the sludge is to be deposited, so that it can be lifted out with the mud pan at suitable intervals. Such a mud pan consists of a shallow container that is placed on the floor the actual bath container is placed. Experience has shown, however, that a lot of sludge comes out laterally in the gap between the sludge pan and the crucible wall and burns there. As a result, the mud pans are difficult to lift out; a complete Desludging is not possible. Added to this is the disadvantage of heat build-up and thermal Overload at the bottom of the pan.

It is also known to be pocket-shaped in molten salts to be desludged Suspend sieve containers in which the sludge collects. Such: containers are Can be used in salt baths where the use of space does not play a major role, E.g. in hot baths in which workpieces are quenched that only have a small Take up part of the volume of the hot bath.

It is also known (DBP 1 247 361) that in the container for the Molten salt basket-like containers are suspended and these with organs for circulating the molten salt are combined. These containers are only located during the desludging process in the molten salt and therefore do not take up any space during the actual Nitriding process. The whirled up sludge is collected in the sieve baskets and removed.

This desludging device has the disadvantage that very fine-grained Sludge, as it occurs with newer nitriding processes, can no longer be removed can. In addition, desludging with this device is relatively time-consuming.

It was therefore an object of the present invention to provide a device for desludging of molten salts, in particular nitriding baths, to create the bçauem to handle, is not permanently arranged in bath containers., and above all can also remove very fine sludge from the molten salt as quickly as possible.

This object was achieved according to the invention in that one Used in the molten bath insertable container, the cross section of which is substantially corresponds to the cross-section of the bath tank and is characterized by that part of the container jacket and the bottom of the container are provided with sieve surfaces and the bottom can be opened upwards.

The part of the container jacket which is provided with sieve surfaces is advantageous interchangeable.

In the figure is an exemplary embodiment of the inventive Device shown schematically.

The desludging tank inserted in the molten bath tank (7) (6) has a sheet metal jacket (1) 9 suspended in this jacket (1), replaceable, is the part (2) provided with a sieve surface (3), on which the also with The bottom (4) provided with sieve surfaces is attached. The bottom (4) is on a hinge (5) designed to be hinged upwards with the help of a chain or a pull rope (8). The sieve surfaces (3) exist advantageously from a fine-meshed Metal wire mesh that is held between perforated sheets.

For desludging, the container (6) is slowly lowered into the bath (7). When the bottom (4) is raised, the melt can enter the desludging tank unhindered (6) penetrate. Immediately after the desludging device (6) at the bottom of the bath tank (7) is seated, the container (6) can be pulled out of the bath. It will the bottom (4) with a loose chain (8) pressed down so that the container (6) forms a closed vessel.

The melt can only be removed from the desludging vessel through the sieve surfaces (3) (6) run off, thereby the Schlalilmpartikel remain on the sieve surfaces (3).

In principle, this desludging is similar to filtering the bath, however, the melt does not have to be pumped through the filter. By repetition During the desludging process, the residual sludge content can be reduced again.

Compared to the known desludging device, not only one Much better desludging is achieved, but the desludging time is considerable shortened.

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Claims (2)

PATENT CLAIMS 1. Device for desludging of molten salts, in particular nitriding baths, with a container which can be inserted into the bath, the cross section of which substantially corresponds to the cross section of the bath tank, characterized in that that a part (3) of the container jacket (1) and the bottom (4) of the container with sieve surfaces are provided and the bottom (4) can be folded up. 2. Apparatus according to claim 1, characterized in that the with sieve surfaces (3) provided part (2) of the container shell (1) is exchangeable.