DE1257748B - Device for forming spheres from granular material with a high melting point - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

BOIj

German KL: 12 g -1/01

Number: 1257748

File number: E 25696IV a / 12 g

Filing date: October 17, 1963

Open date: January 4, 1968

The invention relates to an apparatus for forming beads of granular material with high Melting point, consisting of a working gas space connected to a supply line for working gas, an ionization arrangement with an anode and a cathode, one with the working gas space connected supply line for the granular material and an opening in the working gas space for the outlet the globules.

With such devices in which the plasma normally moves radially around an electrode forms, it has hitherto hardly been possible to satisfactorily produce beads with a diameter of more than 200 μπα to produce.

The object of the invention is therefore to provide a device of the type mentioned at the outset, with which makes it possible to produce beads with a high melting point up to a size of 700 μm.

This object is achieved according to the invention in that the device contains a melting chamber, which has the following parts:

on its upper side a material supply line, a working gas supply line surrounding it, a ring encasing the outlets of the lines and a first ring-shaped electrode, which surrounds the ring, the ring over the first electrode in the direction of movement of the particles protrudes, consists of an electrically conductive material and is electrically conductive with the annular electrode is connected, also an outlet from the underside Melting chamber, the central axis of which forms the extension of the central axis of the ring and is part of the ionization arrangement,

and that a cooling space for the beads is connected to the melting space.

This arrangement ensures that the particles are in the for a relatively long time The area of the highest temperature, d. H. essentially on the central axis of the plasma that in the device of the invention has a suitable cylindrical configuration.

Between the ring, which forms an extension of the first electrode, and electrically with it Is conductively connected, and the exit from the melting chamber forms a cylindrical plasma column from, in which the particles to be formed are introduced axially and in which they during their Movement are kept. The particles then enter a cold room. The plasma is light adjustable. With the conventional devices was

Apparatus for forming beads from
granular material with a high melting point

Applicant:

European Atomic Energy Community (EURATOM),

Brussels

Representative:

Dipl.-Ing. R. Müller-Borner

and Dipl.-Ing. H.-H. Wey, patent attorneys,

1000 Berlin-Dahlem, Podbielskiallee 68

Named as inventor:

Thomas A. J. Jaques,

Radipole-Weymouth, Dorset;

Richard T. Smyth,

Winton, Bournemouth, Hampshire;

Derek William Sturge,

Dorchester, Dorset (Great Britain)

Claimed priority:

Great Britain October 26, 1962 (40 569)

it is not possible to keep the particles in the hottest zone for a long time.

It is advantageous to design the device so that sub-atmospheric pressure in the working space prevails.

To a further improvement of the properties of the device according to the invention it contributes that the outlet from the melting chamber is nozzle-shaped.

For the formation of the second electrode, two embodiments are possible, namely that the Exit forms the second electrode or that the second electrode is eccentric to the first electrode is arranged outside the melting chamber and the outlet is designed as a collimator. Both options can bring advantages depending on the required properties of the device.

An embodiment of the invention is shown in the drawings and will be described in more detail below explained. It shows

F i g. 1 shows a longitudinal section through an embodiment of a device according to the invention and

709 717/579

Claims (5)

3 4 2 shows a schematic view of a system. The outlet 24 'can be the cathode of the plasma veins The core of a device according to FIG. 1 form a generator, but it can also be used as a collimator can. act, then the cathode 24 ″ from a The device according to FIG. 1 is composed of its water-cooled tungsten part that is generally symmetrical about the axis XX. 5 outlet axially separated and connected to its center line F i g. 1 shows a cooling space 1 in which a is arranged below. atmospheric pressure can be generated and at In operation the pressure in the chamber is 1 to which is reduced to 10 Torr on its upper side a melting chamber, with the plasma generator closes, which is supplied with a supply pipe 2 for connection to working gas and for maintaining a a supply of granular material with an irregular gas plasma relative to that in the chamber has a moderate surface. Sufficient tension on the underside of the prevailing negative pressure An outlet opening 3 is provided in the cooling chamber 1. the cathode and the anode is applied. The too In the vicinity of the inlet tube 2 is a plasma generator bead to be transformed by particles Tor 4 attached, the sufficient heat to the material supply line 6 ″ supplied through and Melting of the particles is generated. 15 pass through the graphite ring 16 into the center The plasma generator 4 has a first electrode of the plasma in, where they melt and close trode 5, in the exemplary embodiment the anode, which transform the spherical particles. The particles flow at one end of a short tube 7 from isolate after it has melted through the one in the cooling space the material is arranged, which has an inner absent opening. Theorem 7 has α . 20 By introducing the particles to be melted The anode 5 has the shape of a copper ring 8 provided with a groove in the middle of the plasma, which rests on the upper side of the paragraph la during which the particles are in the hot area, whereby the upper edge stop the groove, lengthen it, cutting axially with the end face 7 & of the tube 7. Separating the anode from the cathode instead of the more common radial separation from a given end plate 9, which is fastened by means of bolts 10 on the end face Ib , closes the groove in the ring 8 for a longer dwell time for the particles and thus forms a cooling channel 11 for high temperature is achieved, the anode. The front plate 9 is equipped with a cooling system suitable for small production quantities. center inlet 12 and a coolant outlet 13 and location for forming beads is shown in FIG. 2 as well placed through a central opening 14 through 30. broken, which is used to receive the feed unit of In F i g. 2 is the plasma generator that is used by the in an insulator 15 is surrounded. The feed unit 6 F i g. May be the type described 1 at the top contains an attached to a Teilchenvorrat end of a cooling column 51 is provided, which so angeord material supply line 6 a and a net is to a work that it molten in the plasma gas supply connected the working gas feed line 6 b 35 particles records. The wall of the column is in the form of an outer concentric and coaxial one extending helically to the pipe. Sealing rings form a gas-tight outer side of the wall-mounted coil 52 seal between the adjacent cools, through which water can be passed, the surfaces of the face plate 9, the pipe 7 and the with over the line 53 is let in and over the grooved Ring 8. At the inner passage 40 line 54 flows off. The lower portion of the wall knife of the ring 8 is a spacer 8 a from iso is funnel-shaped and directs the fixed in free floating material from which a graphite flight cooled particles into a tube 55, the ring 16 hangs down. The outlets of the lines 6 a and 6 b into a portable vessel 56 containing cooling oil are thus coaxially suspended around the ring 16. The inside of the pillar is for the purpose of forgiveness. 45 Reduction of the pressure in the device to 10 Torr In the end remote from the face plate 9 via the line 57 to a vacuum pump 58 and the tube 7, an annular part 17 is fitted, closed. the separately arranged flanges 17 a, the view according to FIG. 2 shows the plasma generator 17 b and a central tubular portion gate 50 from the outside. It has connections 59, 60, 61 17 c. The flanges 17a, V7b have a diameter 50 and 62 for the inlet and outlet of a cooling liquid such that the flange 17a, the one and an inlet line 63 for working gas, which is fed from a sealing ring extending on its outer circumference of a bottle 64. 18 has, to the pipe 7 and against the Ab- Preferably is because of its high thermal conductivity 7a can apply while the flange 17 & is able to use helium as the working gas, however against the end face of the tube 7, on which it 55 can also be any other center in its place Bolts or screws 19 is attached. A suitable gas can be used. Sealing ring 20 enables a satisfactory As an example of that in the pre-seal described for a product manufactured between the outer circumference of the direction have been used tubular section 17 c, the flanges 17 a, of helium gas in an amount of 128 l / min part-17 δ and the inside of the tube 7 processed 60 surfaces made of uranium and thorium carbide. Annular chamber 21. The inner surface of the tubular section 17c claims: is with a ring made of graphite or other suitable refractory material; and 1. apparatus for forming beads thus forms a nozzle-shaped outlet 24 '. The wall 65 granular material with a high melting point, loading of the tube 7 has (not shown) openings, standing out from a with a supply line for the chamber 21 connected to the coolant supply and working gas working gas space, one -Connect return lines 22 or 23. Ionization arrangement with an anode and a Cathode, a supply line for the granular material connected to the working gas space and an opening in the working gas space for the outlet of the beads, characterized in that that the device contains a melting chamber which has the following parts: on its upper side a material supply line (6 a), a working gas supply line (6 &) surrounding it, a ring (16) which encases the ends of the lines (6 a, 6 b) , and a first annular electrode (S, 8) which surrounds the ring (16), the ring (16) protruding beyond the first electrode (5, 8) in the direction of movement of the particles, made of an electrically conductive material and electrically conductively connected to the ring-shaped electrode (8), and also to its Underside an outlet (24 ') from the melting chamber, the central axis of which forms the extension of the central axis (XX) of the ring (16) and is part of the Ionization arrangement is
and that a cooling chamber (1) for the beads is connected to the melting chamber. 2. Apparatus according to claim 1, characterized in that the working gas space is designed is that sub-atmospheric pressure can be used. 3. Apparatus according to claim 1 or 2, characterized in that the outlet (24 ') from the melting chamber is designed in the shape of a nozzle. 4. Device according to one of claims 1 to 3, characterized in that the outlet (24 ') forms the second electrode. 5. Device according to one of claims 1 to 3, characterized in that the second Electrode (24 ") arranged eccentrically to the first electrode (5, 8) outside of the melting chamber and the outlet (24 ') is designed as a collimator. 1 sheet of drawings