US2145198A - Device for mechanically treating thixotropes - Google Patents

Description

Jan. 24,-f 1939. s. KlES SKALT 5,

DEVICE FOR MECHANICALLY TREATING THIXOTROPES Filed April 15, 1955 INVENTOR'.

I fim m w W ATTORNEY m an amplitude of about several millimeters.

Patented Jan. 24, 1939 UNITED STATES PATENT OFFICE DEVICE FOlt IVIECHANICALLY TREATING THIXOTROPES Main, Germany Application April 15, 1935, Serial No. 16,530 In Germany April 21, 1934 3 Claims.

The present invention relates to a device for mechanically treating thixotropes, more particularly to a device for mechanically treating agglomerated thixotropes which seem to be solid, in order to loosen them, to reduce them to small pieces or to render them fluid totally or partially. The method uses the property of some moist substances which is usually called thixotropy in the colloid physics. These substances seem to 'be solid or plastic when at rest, but they become fluid when sufiiciently stirred by shearing action, shock or vibration. Many organic or inorganic products show this property, for instance filter press cakes, suction filter residues, furt ermore,

15 some dry revolving furnace clinkers, slaked lime,

mud-like sludge, coal-tar dyes or the like.

The method starts from the following observation: if, for instance, at a tuning fork a steel needle is fastened and this system is caused to oscillate and the vibrating needle is held to the surface of a piece of a thixotrope, the needle very easily penetrates into the solid or viscous mass and leaves a distinct trace. Practically no matter remains attached-to the needle itself.

a The device comprises a box at the bottom of which a sufliciently large number of elastic vertical needles of length, strength and form adapted to the intended use are mounted, for instance on a membrane excited by an alternating ourrent magnet or by a similarly acting device.

When the alternating circuit is closed, the membrane oscillates in known manner like a diaphragm of an alternating current telephone or an electric horn. The needles are thus intensively oscillated, so that the coarse-grained thixotropes can be reduced to small pieces by pressing, filling or pouring the mass upon these needles. It is possible to draw any desired paths through the mass by moving manually or mechanically o the bottom of the device. The size of the pieces obtained by this action depends on the distance between the needles. If the distance is sufficiently small and the frequency and amplitude of oscillation are the optimum for the material 45 treated, it is possible to reduce the material to thin fluid condition which is called a paste in many industries. It is suitable to apply oscillations of a frequency of about several hundreds to about several thousands per minute and of The frequency of oscillations may amount to about 700-5000per minute and the amplitude of oscillation may be 0.5-7 millimeters.

A disintegration of an agglomerated mass of u this kind has been found to be particularly advantageous if the mass has to be dried in hot air in drying chambers. By the extensive cleavage of the mass the drying process is greatly accelerated. A pre-treatment according to this process is equally useful if the thixotropes have to be uniformly treated by penetration of a chemically active gas or if the masses have to be. immersed into liquids for dissolution or reaction.

The accompanying drawing shows a cross section through a trough-shaped box e at the bottom of which several rows of electro-magnetlcally operated needles I are inserted, each row containing three sets. 'g g and g are electromagnetic oscillating systems. The oscillating systems 'are fed by an alternating current through the lead h. Each of the electro-magnetic oscillating systems consists of a solenoid c and a core (1 by means of which a superimposed membrane z' is excited to.oscillations with the aid of the alternating current. Upon the membrane the needles I are welded upwardly.

'The membranes i consist of iron plate of a thickness of about 0.5 mm. They are maintained by a cap screw 1) which is screwed upon the case a. The case a which contains the electrd-magnetic system is screwed into'a bore of the box e.

Pieces of press cake thrown into the box are first loosenedby the oscillations of the needles I and then liquefied or transformed into a paste according to their thixotropic properties. They thus become, at least transitorily, fiuid in condition and may be removed by tipping the box or may be run off in a coherent condition through a suitable outlet of any desired shape. A device of this kind comprising 200 needles set in a box measuring 500x300 mm. and oscillated with a frequency of 2900per minute and an amplitude of 3 mm. measured at the points of .inser- ,tion, can produce from pieces of press-cake of "an organic dyestuff 1500 kilos of paste per hour.

While a preferred embodiment of the invention has been shown and described by way of illustration, it will be understood that various modifications of the invention may be resorted to without departing from the spirit of the invention within the scope of the appended claims.

I claim:

1. A device for mechanically treating thixotropes which comprises a box at the bottom of which vertical needles are inserted and means causing the needles to oscillate relative to said box of a frequency of between 700 and 5000 per minute and an amplitude of 0.5 to '7 millimeters. 1

2. A device for mechanically treating thixotropes which comprises a box for the reception tropes which comprises a box at the bottom of of thixotropes, a membrane afllxed at the bottom which vertical needles are inserted and means of said box and vertical needles mounted on said causing the needles to oscillate relative to said membrane which are capable of being caused to 5 box of a frequency of about 2900 per minute oscillate relative to the said box by electromag- 5 and an amplitude of up to 3 millimeters. netic means.

3. A device for mechanically treating 'thixo- SIEGFRIED KIESSKALT.

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