Title of Invention	PORTABLE DROSS PROCESSING APPARATUS
Abstract	A portable dross processing apparatus (1). A vertical frame comprising a bottom portion (2) and a vertical portion (3) is provided with castor wheel (4) at the bottom thereof and a platform (5) at the top thereof. A semispherical reaction vessel (6) is pivotally mounted at an intermediate location in the vertical frame and provided with a handle (11) and at least two diametrically opposite discharge ports (10, 10) at the curvature at the bottom thereof in the proximity of the center thereof. An electric motor (12) is mounted on the platform with its shaft (13) directed horizontally. A speed reduction gear box (14) is mounted on the platform i the proximity of the electric motor with its input shaft (15) and output shaft (16) horizontally directed at right angle to each other. The input shaft of the gear box is coupled to the motor shaft. An agitator (17) is up and down movably held in the platform aligned with respect to the reaction vessel. Drive transmitting means comprising a first bevel gear (24) is provided to interconnect the output shaft of the gear box and the agitator shaft so as to rotate the agitator in the vertical plane. A rope and pulley arrangement comprising a wire rope (34) connected to the agitator and running over a pulley (33) and wound over a spool (35) is provided to move the agitator up and down.

Title of Invention

PORTABLE DROSS PROCESSING APPARATUS

Abstract

A portable dross processing apparatus (1). A vertical frame comprising a bottom portion (2) and a vertical portion (3) is provided with castor wheel (4) at the bottom thereof and a platform (5) at the top thereof. A semispherical reaction vessel (6) is pivotally mounted at an intermediate location in the vertical frame and provided with a handle (11) and at least two diametrically opposite discharge ports (10, 10) at the curvature at the bottom thereof in the proximity of the center thereof. An electric motor (12) is mounted on the platform with its shaft (13) directed horizontally. A speed reduction gear box (14) is mounted on the platform i the proximity of the electric motor with its input shaft (15) and output shaft (16) horizontally directed at right angle to each other. The input shaft of the gear box is coupled to the motor shaft. An agitator (17) is up and down movably held in the platform aligned with respect to the reaction vessel. Drive transmitting means comprising a first bevel gear (24) is provided to interconnect the output shaft of the gear box and the agitator shaft so as to rotate the agitator in the vertical plane. A rope and pulley arrangement comprising a wire rope (34) connected to the agitator and running over a pulley (33) and wound over a spool (35) is provided to move the agitator up and down.

Full Text	FORM 2 THE PATENTS ACT, 1970 (39 of 1970) As amended by the Patents (Amendment) Act, 2005 & The Patents Rules, 2003 As amended by the Patents (Amendment) Rules, 2005 COMPLETE SPECIFICATION (See section 10 and rule 13) TITLE OF THE INVENTION Portable dross processing apparatus INVENTORS Nikam Murlidhar Narayan, Rajan Suresh and More Sachin, all Indian nationals and all of Crompton Greaves Limited, Material and Process Center, Kanjur Marg (East), Mumbai 400042, Maharashtra, India APPLICANTS Name : CROMPTON GREAVES LIMITED Nationality: Indian Company Address : CG House, Dr Annie Besant Road, Prabhadevi, Mumbai 400025, Maharashtra, India PREAMBLE TO THE DESCRIPTION The following specification particularly describes the nature of this invention and the manner in which it is to be performed: FIELD OF INVENTION This invention relates to a portable dross processing apparatus. During melting of metals and holding of metal melts in furnaces, drosses are formed on the surfaces of the metal melts. In order to reduce metal losses, metals entrapped in the drosses are reclaimed or recovered. BACKGROUND OF INVENTION US Patent No 6464929 describes a dross processing system comprising a reaction vessel pivotably or fixedly mounted with respect to a reaction vessel support which in turn is rotatably or fixedly mounted to a substantially vertical support. The reaction vessel comprises a substantially vertical sidewall terminated in an upper rim and a lower rim. A concave bottom member is attached to the lower rim of the reaction vessel and is provided with a discharge port at the center thereof. The discharge port is sealable with a plug fabricated from a refractory fiber material such as alumino silicate. A removable plug support plate is positioned below the discharge port and is maintained in position by a plate support rack attached to the bottom of the reaction vessel. The reaction vessel can also be double walled construction. A motor is mounted on a motor arm with its drive shaft directed vertically downwardly towards the reaction vessel. An impeller is attached to the free end of the motor shaft. The motor arm is height adjustably connected to the substantially vertical support in order to displace it with respect to the reaction vessel. A linear actuator comprising a hydraulic actuator or a rack and pinion 2 gearing driven by a gear motor or a counter weight system is used to displace the motor with respect to the reaction vessel. The motor arm can also be rotatable with respect to the substantially vertical support or fixed or pivotable with respect to the substantially vertical support. The motor arm is provided with a protective shield configured to engage the upper rim of the reaction vessel. The substantially vertical support is positioned close to the furnace by supporting it in a bracket affixed to the furnace or mounted on wheels or on a stand. The motor position can be adjustable on the arm thereof. The protective shield can be resiliency mounted so that the motor arm can be maintained in multiple lowered positions with the protective shield biased towards engagement with the upper rim of the reaction vessel by compression springs. The impeller comprises a plurality of radially extending blades or a flat portion formed with a plurality of blades bent upwardly and downwardly. Because of the above blade configuration of the impeller, the entire mass of dross is not evenly and properly agitated and disintegrated into smaller particles so as to release the liquid metal entrapped therein effectively. Therefore, metal recovery is reduced. As the sidewall of the reaction vessel is substantially vertical, flow of liquid metal to the bottom thereof is not smooth and fast. Due to the discharge port being at the bottom centre of the reaction vessel and the bottom of the reaction vessel being concave, there is accelerated convergence of the liquid metal at the centre of the reaction vessel. Centrifugal forces at the centre of the reaction vessel also will be high. As a result, the discharge port is prone to clogging frequently. Besides, discharge of the liquid metal is also reduced as there is only one port. All this further reduces metal recovery. Arrangements such as linear actuator, rack and pinion gearing driven by gear motor or counter weight system 3 for displacement of the motor arm are expensive. Gear motor is also energy consuming. Gear motor and linear actuator also require maintenance . As the motor is vertically mounted with its arm directed downwardly, axial load on the motor during its operation is high. Besides, it will also be subjected to radial load. This increases energy consumption by the motor. Besides, the motor arm is subjected to excessive vibrations and should be structurally strong to bear the loads. The vibrations also lead to noise. In case the impeller is required to be dismantled for repair or replacement, the entire impeller has to be dismantled thereby rendering impeller repair or replacement difficult and cumbersome and also time consuming. OBJECTS OF INVENTION An object of the invention is to provide a portable dross processing apparatus, which improves metal recovery. Another object of the invention is to provide a portable dross processing apparatus, which prevents choking of discharge ports of the reaction vessel thereof Another object of the invention is to provide a portable dross processing apparatus, which is simple in construction, compact and is practically maintenance free. Another object of the invention is to provide a portable dross processing apparatus, which facilitates easy repair or replacement of the agitator thereof. 4 Another object of the invention is to provide a portable dross processing apparatus in which axial loads on the motor are eliminated thereby reducing vibrations and noise of the motor during operation thereof and also structural strength requirement of the motor. Another object of the invention is to provide a portable dross processing apparatus, which reduces energy consumption and cost and is economical. DETAILED DESCRIPTION OF THE INVENTION According to the invention there is provided a portable dross processing apparatus comprising a vertical frame provided with castor wheels at the bottom thereof and a platform at the top thereof, a semispherical reaction vessel pivotally mounted at an intermediate location in the vertical frame and provided with a handle and at least two diametrically opposite discharge ports at the curvature at the bottom thereof in the proximity of the center thereof, an electric motor mounted on the platform with its shaft directed horizontally, a speed reduction gear box mounted on the platform in the proximity of the electric motor with its input shaft and output shaft horizontally directed at right angle to each other, the input shaft of the gear box being coupled to the motor shaft, an agitator up and down movably held in the platform aligned with respect to the reaction vessel, drive transmitting means interconnecting the output shaft of the gear box and the agitator shaft to rotate the agitator in the vertical plane and a rope and pulley arrangement connected to the agitator for moving the agitator up and down. 5 The following is a detailed description of the invention with reference to the accompanying drawings, in which: Fig 1 is front side isometric view of a dross processing apparatus according to an embodiment of the invention; Fig 2 is back side isometric view of the dross processing apparatus of Fig 2; Fig 3 is top view of the reaction vessel of the dross processing apparatus of Fig 1; Fig 4 is an isometric view of the agitator of the dross processing apparatus of Fig 1; Fig 5 is a top end isometric view of the second bevel gear of the dross processing apparatus of Fig 1; Fig 6 is vertical cross section of the second bevel gear of the dross processing apparatus of Fig 1; Fig 7 is vertical cross section of the hollow support member of the dross processing apparatus of Fig 1 with the bush bearing located therein; and Fig 8 is an enlarged scrap view of the slider and corresponding end of the spool of the dross processing apparatus of Fig 1; 6 The dross processing apparatus 1 as illustrated in Figs 1 to 8 of the accompanying drawings comprises a vertical frame comprising a square shaped bottom frame portion 2 and a rectangular vertical frame portion 3 (Figs 1 an d 2). The bottom frame portion is provided with castor wheels 4. The lower end of the vertical frame portion is fixed to the bottom frame portion and the top of the vertical frame portion is provided with a platform 5. 6 is a semispherical reaction vessel provided with a pair of trunnions 7,7 (Figs 1, 2 and 3). Each of the trunnions is pivoted on a cross member 8 at each side of the vertical frame portion using clamp 9. The cross members are fixed to the vertical frame portion at an intermediate location thereof. The reaction vessel is also provided with two diametrically opposite discharge ports 10, 10 at the curvature at the bottom thereof in the proximity of the center thereof preferably at a distance of 40 to 55 cms from the center thereof. Each of the discharge ports is preferably 7-9 mm diameter in size. The reaction vessel is further provided with a handle 11 fixed to one of the trunnions. 12 is an electric motor mounted on an extension 5a of the platform with its shaft 13 directed horizontally. 14 is a speed reduction gear box mounted on the platform in the proximity of the electric motor with its input shaft 15 and output shaft 16 horizontally directed at right angle to each other . The input shaft 15 of the gear box is coupled to the motor shaft 13. 17 is an agitator up and down movably held aligned with respect to the reaction vessel (Figs 1, 2 and 4). The agitator shaft comprises an upper part 19 and lower part 20 provided with flanges 19a and 20a, respectively (Fig 4). The upper part and lower part of the agitator shaft are detachably fixed to each other by bolting (bolts not shown) the respective flanges. The agitator comprises a hollow semicircular member 21 fixed to 7 the lower end of the lower part of the agitator shaft and corresponding to the inner surface of the reaction vessel (Figs 1, 2 and 4). 22a, 22b and 22c are three spaced vertical ribs disposed within the semicircular member and fixed thereto (Fig 4). 23, 23 are a pair of horizontal projections projecting from the middle rib in opposite directions perpendicular to the plane of the semicircular member and corresponding to the inner surface of the reaction vessel (Fig 4), 24 is a first bevel gear mounted on the output shaft of the gear box (Fig 2). 25 is a second bevel gear horizontally disposed on the platform and provided with a hub 26 projecting downwardly therefrom (Figs 1,2,5 and 6). The first bevel gear is in mesh with the second bevel gear 25 whose hub 26 is vertically rotatably held in an upright hollow support member 27 formed with a pair of flanges 27a and 27b at the bottom and top thereof. The support member is mounted on the platform by bolting (bolts not shown) the bottom flange 27a to the platform. The second bevel gear is supported against the top flange 27b. The hub of the second bevel gear is rotatable in the hollow support member against a bush bearing 28 located in the support member (Fig 7). The agitator shaft is provided with an oblong groove 29 partially along the upper end thereof (Figs 1 and 2). The second bevel gear and the hub thereof are provided with an oblong protrusion 30 along the inner surface thereof (Figs 5 and 6). The protrusion 30 corresponds to the oblong groove on the agitator shaft upper end. The agitator shaft is disposed in the second bevel gear and hub with the oblong groove engaged over the oblong protrusion such that the agitator shaft is movable up and down in the second bevel gear with the agitator. The up and down movement of the agitator shaft is guided by the oblong protrusion in the second bevel gear and the hub thereof. The agitator shaft and agitator rotate with the second bevel gear as the oblong groove on the agitator shaft upper 8 end is engaged over the oblong protrusion in the second bevel gear and hub. A pair of spaced angular arms 32, 32 are vertically supported on the platform (Figs 1 and 2). 33 is a pulley rotatably held between the free ends of the arms and 34 is a wire rope running over the pulley and wound over a spool 35. One end of the wire is fixed to a clip 36 which in turn is fixed to the free end of the agitator shaft. The other end of the wire rope is fixed to the spool. The spool is rotatably held in a pair of brackets (not shown) laterally extending from either side of the top of the frame. The spool comprises a pair of circular end flanges 36a, 36b. The end flange 36a is provided with a handle 37 and a pair of diametrically opposite open slots 38, 38 at the circumference thereof (Fig 8). 39 is an oblong slider aligned with the circumference of the end flange 36a and horizontally slidably held to the vertical frame at the top thereof between oblong sections 40, 40 fixed to the vertical frame at the top thereof (Fig 8). One end of the oblong slider is adapted to engage in and disengage from the open slots at the circumference of the end flange 36a. The oblong slider is manually moved in and out of the open slots at the circumference of the end flange 36a sequentially. The other end of the oblong slider is provided with a tapered protruberance 41 for hand grip and manual operation thereof. The agitator is moved up and down in the second bevel gear and hub thereof with respect to the reaction vessel by rotating the spool holding the handle thereof and winding and unwinding the wire rope on the spool. The pulley rotates and facilitates the up and down travel of the agitator, which corresponds to the center to center circumferential distance between the open slots at the circumference of the end flange 36a. The rotation of the spool and winding and unwinding of the wire rope on the spool is arrested and the agitator is held at the upper and lower positions thereof by engaging the oblong slider in the respective 9 open slot at the circumference of the end flange 36a. During operation of the apparatus of the invention, drosses formed on the surfaces of metal melts in furnaces and at around 800 to 950°C are loaded into the reaction vessel. Exothermic compounds such as salts of potassium and sodium chlorides are added to the reaction vessel in order to increase the temperature of the dross mass. The agitator is lowered down into the reaction vessel by rotating the spool and unwinding the wire rope in one direction and is held in the lowered position by engaging the oblong slider in the respective open slot in the circumference of the end flange 36a. The agitator is rotated by switching on the motor. The first bevel gear rotates in the horizontal plane with the output shaft of the gear box and drives the second bevel gear in the vertical plane. The agitator rotates with the second bevel gear in the vertical plane thereby churning and stirring the dross in the reaction vessel. The RPM of the motor, gear ratio of the gear box and teeth ratio of the first bevel gear and second bevel gear are selected to give a rotational speed of 70 to 100 per minute to the agitator. Due to the geometry and configuration of the agitator, the dross is agitated and churned in all the directions disintegrating the dross mass into smaller particles effectively thereby increasing the release of liquid metal entrapped in the dross. Because of the semispherical geometry of the reaction vessel, the liquid metal flows down to the bottom of the vessel smoothly rapidly. As there are two discharge ports located at the curvature of the reaction vessel diametrically opposite, the liquid metal flows out from the reaction vessel rapidly thereby increasing the metal recovery. The centrifugal forces at the curvature of the reaction vessel is less as compared to that at the center of the reaction vessel. Due to the reduced 10 centrifugal force and presence of the two discharge ports outflow of the liquid metal is further improved. Presence of two discharge ports also reduces the residence time of the liquid metal in the reaction vessel. Due to the rapid outflow of the liquid metal, choking of the discharge ports is prevented. The out flowing metal is collected in a pan (not shown) disposed below the discharge ports and processed further in known manner. On completion of the metal recovery, the motor is switched off and the agitator is raised from the reaction vessel by rotating the spool in the opposite direction and winding the rope on the spool. The agitator is held in the raised position by engaging the oblong slider in the respective oblong slot at the circumference of the end flange 36a. The spent dross or skull dross is emptied from the reaction vessel by tilting it about the pivot thereof by holding the respective handle. The agitator can be assembled to and dismantled from the upper part of the agitator shaft easily because of the bolt fit. Therefore, assembly and disassembly of the agitator for repairs or replacement thereof is easy and convenient and it is not necessary to dismantle the entire agitator from the vertical frame for such purpose. As the motor is mounted in the horizontal plane axial forces on the motor are reduced. Therefore, energy consumption by the motor is reduced. Vibration of the motor is also reduced thereby reducing the noise level of operation thereof. The strength requirement of the structural support of the motor is also reduced. The rope and pulley arrangement for raising and lowering the agitator is very simple in construction and operation and does not consume any energy. The construction of the dross processing apparatus as a whole is simplified and it is very convenient to operate it. Besides increasing metal recovery and preventing choking of the metal parts, the apparatus is also practically maintenance free. It consumes reduced energy and is cost effective and 11 economical. Due to its portability the apparatus can be positioned close or away from the furnace as per convenience of the operator. The vertical frame may be of a different construction/configuration. There can be more than two discharge ports in the reaction vessel. The rope and pulley arrangement can be of a different construction / configuration. The agitator can be of a different construction/configuration. The drive transmitting means can be of a different construction/configuration. Such constructional changes of the invention are obvious variations and are to be construed and understood to be within the scope of the invention. 12 We claim : 1. A portable dross processing apparatus comprising a vertical frame provided with castor wheels at the bottom thereof and a platform at the top thereof, a semispherical reaction vessel pivotally mounted at an intermediate location in the vertical frame and provided with a handle and at least two diametrically opposite discharge ports at the curvature at the bottom thereof in the proximity of the center thereof, an electric motor mounted on the platform with its shaft directed horizontally, a speed reduction gear box mounted on the platform in the proximity of the electric motor with its input shaft and output shaft horizontally directed at right angle to each other, the input shaft of the gear box being coupled to the motor shaft, an agitator up and down movably held in the platform aligned with respect to the reaction vessel, drive transmitting means interconnecting the output shaft of the gear box and the agitator shaft to rotate the agitator in the vertical plane and a rope and pulley arrangement connected to the agitator for moving the agitator up and down. 2. A portable apparatus as claimed in claim 1, wherein the discharge ports are at a distance of 40 to 55 cms from the center of the reaction vessel and each of the discharge ports is 7-9mm diameter. 3. A portable apparatus as claimed in claim 1 or 2, wherein the agitator comprises a hollow semicircular member fixed to the lower end of the agitator shaft and corresponding to the inner surface of the reaction vessel, at least three spaced 13 vertical ribs disposed within the semicircular member and fixed thereto and at least one pair of horizontal projections projecting from at least the middle rib in opposite directions perpendicular to the plane of the semicircular member and corresponding to the inner surface of the reaction vessel. 4. A portable apparatus as claimed in anyone of claims 1 to 3, wherein the agitator shaft is of two piece construction comprising an upper part and a lower part adapted to be detachably fitted to each other, the agitator being fixed to the lower end of the agitator shaft. 5. A portable apparatus as claimed in anyone of claims 1 to 4, wherein the vertical frame comprises a square shaped bottom frame portion provided with castor wheels and a rectangular vertical frame portion whose lower end is fixed to the bottom frame portion and upper end is provided with the platform. 6. A portable apparatus as claimed in anyone of claims 1 to 5, wherein the reaction vessel is provided with a paid of trunnions, each of the trunnions being pivoted on a cross member fixed to the vertical frame portion at an intermediate location at each side thereof, the handle of the reaction vessel being fixed to one of the trunnions 7. A portable apparatus as claimed in any one of claims 1 to 6, wherein the drive 14 transmission means comprises a first bevel gear mounted on the output shaft of the gear box in mesh with a second bevel gear which is horizontally disposed and vertically rotatably supported on the platform, the agitator shaft being up and down movably held in the second bevel gear and being rotatable with the second bevel gear. 8. A portable apparatus as claimed in claim 7, wherein the second bevel gear is provided with a hub projecting downwardly therefrom, the hub being vertically rotatably held in an upright hollow support member formed with a pair of flanges one at the bottom and the other at the top thereof, the support member being mounted on the platform by bolting the bottom flange thereof to the platform and the second bevel gear being supported against the top flange of the support member, the agitator shaft being provided with an oblong groove partially along the upper end thereof and engaged over a correspondingly profiled oblong protrusion provided in the second bevel gear and the hub along the inner surface thereof, the up and down movement of the agitator shaft being guided by the oblong protrusion. 9. A portable apparatus as claimed in claim 8, wherein the second bevel gear is rotatably held in the support member over a bush bearing. 10. A portable apparatus as claimed in any one of claims 1 to 9, wherein the rope and pulley arrangement comprises a pair of spaced angular arms vertically supported 15 on the platform, a pulley rotatably held between the free ends of the arms and a wire rope running over the pulley and wound over a spool, one end of the wire rope being fixed to the free end of the agitator shaft and the other end of the wire rope being fixed to the spool, the spool being rotatably held to the frame at the top thereof and comprising a pair of circular end flanges one of which is provided with a handle, said one end flange being further provided with a pair of diametrically opposite open slots at the circumference thereof and an oblong slider aligned with the circumference of the said one end flange and horizontally slidably held to the vertical frame at the top thereof, one end of the oblong slider being adapted to be engaged in and disengaged from the open slots in the said one end flange sequentially and the other end of the oblong slider being provided with a tapered protruberance for hand grip. Dated this 13th day of December 2005. 16 ABSTRACT A portable dross processing apparatus (1). A vertical frame comprising a bottom portion (2) and a vertical portion (3) is provided with castor wheels (4) at the bottom thereof and a platform (5) at the top thereof. A semispherical reaction vessel (6) is pivotally mounted at an intermediate location in the vertical frame and provided with a handle (11) and at least two diametrically opposite discharge ports (10,10) at the curvature at the bottom thereof in the proximity of the center thereof. An electric motor (12) is mounted on the platform with its shaft (13) directed horizontally. A speed reduction gear box (14) is mounted on the platform in the proximity of the electric motor with its input shaft (15) and output shaft (16) horizontally directed at right angle to each other. The input shaft of the gear box is coupled to the motor shaft. An agitator (17) is up and down movably held in the platform aligned with respect to the reaction vessel. Drive transmitting means comprising a first bevel gear (24) in mesh with a second bevel gear (25) is provided to interconnect the output shaft of the gear box and the agitator shaft so as to rotate the agitator in the vertical plane. A rope and pulley arrangement comprising a wire rope (34) connected to the agitator and running over a pulley (33) and wound over a spool (35) is provided to move the agitator up and down (Fig 2).

Full Text

FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION
(See section 10 and rule 13)
TITLE OF THE INVENTION
Portable dross processing apparatus
INVENTORS
Nikam Murlidhar Narayan, Rajan Suresh and More Sachin, all Indian nationals and all of Crompton Greaves Limited, Material and Process Center, Kanjur Marg (East),
Mumbai 400042, Maharashtra, India
APPLICANTS
Name : CROMPTON GREAVES LIMITED
Nationality: Indian Company
Address : CG House, Dr Annie Besant Road,
Prabhadevi, Mumbai 400025, Maharashtra, India
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

FIELD OF INVENTION
This invention relates to a portable dross processing apparatus.
During melting of metals and holding of metal melts in furnaces, drosses are formed on the surfaces of the metal melts. In order to reduce metal losses, metals entrapped in the drosses are reclaimed or recovered.
BACKGROUND OF INVENTION
US Patent No 6464929 describes a dross processing system comprising a reaction vessel pivotably or fixedly mounted with respect to a reaction vessel support which in turn is rotatably or fixedly mounted to a substantially vertical support. The reaction vessel comprises a substantially vertical sidewall terminated in an upper rim and a lower rim. A concave bottom member is attached to the lower rim of the reaction vessel and is provided with a discharge port at the center thereof. The discharge port is sealable with a plug fabricated from a refractory fiber material such as alumino silicate. A removable plug support plate is positioned below the discharge port and is maintained in position by a plate support rack attached to the bottom of the reaction vessel. The reaction vessel can also be double walled construction. A motor is mounted on a motor arm with its drive shaft directed vertically downwardly towards the reaction vessel. An impeller is attached to the free end of the motor shaft. The motor arm is height adjustably connected to the substantially vertical support in order to displace it with respect to the reaction vessel. A linear actuator comprising a hydraulic actuator or a rack and pinion
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gearing driven by a gear motor or a counter weight system is used to displace the motor with respect to the reaction vessel. The motor arm can also be rotatable with respect to the substantially vertical support or fixed or pivotable with respect to the substantially vertical support. The motor arm is provided with a protective shield configured to engage the upper rim of the reaction vessel. The substantially vertical support is positioned close to the furnace by supporting it in a bracket affixed to the furnace or mounted on wheels or on a stand. The motor position can be adjustable on the arm thereof. The protective shield can be resiliency mounted so that the motor arm can be maintained in multiple lowered positions with the protective shield biased towards engagement with the upper rim of the reaction vessel by compression springs. The impeller comprises a plurality of radially extending blades or a flat portion formed with a plurality of blades bent upwardly and downwardly. Because of the above blade configuration of the impeller, the entire mass of dross is not evenly and properly agitated and disintegrated into smaller particles so as to release the liquid metal entrapped therein effectively. Therefore, metal recovery is reduced. As the sidewall of the reaction vessel is substantially vertical, flow of liquid metal to the bottom thereof is not smooth and fast. Due to the discharge port being at the bottom centre of the reaction vessel and the bottom of the reaction vessel being concave, there is accelerated convergence of the liquid metal at the centre of the reaction vessel. Centrifugal forces at the centre of the reaction vessel also will be high. As a result, the discharge port is prone to clogging frequently. Besides, discharge of the liquid metal is also reduced as there is only one port. All this further reduces metal recovery. Arrangements such as linear actuator, rack and pinion gearing driven by gear motor or counter weight system
3

for displacement of the motor arm are expensive. Gear motor is also energy consuming. Gear motor and linear actuator also require maintenance . As the motor is vertically mounted with its arm directed downwardly, axial load on the motor during its operation is high. Besides, it will also be subjected to radial load. This increases energy consumption by the motor. Besides, the motor arm is subjected to excessive vibrations and should be structurally strong to bear the loads. The vibrations also lead to noise. In case the impeller is required to be dismantled for repair or replacement, the entire impeller has to be dismantled thereby rendering impeller repair or replacement difficult and cumbersome and also time consuming.
OBJECTS OF INVENTION
An object of the invention is to provide a portable dross processing apparatus, which
improves metal recovery.
Another object of the invention is to provide a portable dross processing apparatus, which prevents choking of discharge ports of the reaction vessel thereof
Another object of the invention is to provide a portable dross processing apparatus, which is simple in construction, compact and is practically maintenance free.
Another object of the invention is to provide a portable dross processing apparatus, which facilitates easy repair or replacement of the agitator thereof.
4

Another object of the invention is to provide a portable dross processing apparatus in which axial loads on the motor are eliminated thereby reducing vibrations and noise of the motor during operation thereof and also structural strength requirement of the motor.
Another object of the invention is to provide a portable dross processing apparatus, which reduces energy consumption and cost and is economical.
DETAILED DESCRIPTION OF THE INVENTION
According to the invention there is provided a portable dross processing apparatus comprising a vertical frame provided with castor wheels at the bottom thereof and a platform at the top thereof, a semispherical reaction vessel pivotally mounted at an intermediate location in the vertical frame and provided with a handle and at least two diametrically opposite discharge ports at the curvature at the bottom thereof in the proximity of the center thereof, an electric motor mounted on the platform with its shaft directed horizontally, a speed reduction gear box mounted on the platform in the proximity of the electric motor with its input shaft and output shaft horizontally directed at right angle to each other, the input shaft of the gear box being coupled to the motor shaft, an agitator up and down movably held in the platform aligned with respect to the reaction vessel, drive transmitting means interconnecting the output shaft of the gear box and the agitator shaft to rotate the agitator in the vertical plane and a rope and pulley arrangement connected to the agitator for moving the agitator up and down.
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The following is a detailed description of the invention with reference to the accompanying drawings, in which:
Fig 1 is front side isometric view of a dross processing apparatus according to an embodiment of the invention;
Fig 2 is back side isometric view of the dross processing apparatus of Fig 2;
Fig 3 is top view of the reaction vessel of the dross processing apparatus of Fig 1;
Fig 4 is an isometric view of the agitator of the dross processing apparatus of Fig 1;
Fig 5 is a top end isometric view of the second bevel gear of the dross processing apparatus of Fig 1;
Fig 6 is vertical cross section of the second bevel gear of the dross processing apparatus of Fig 1;
Fig 7 is vertical cross section of the hollow support member of the dross processing apparatus of Fig 1 with the bush bearing located therein; and
Fig 8 is an enlarged scrap view of the slider and corresponding end of the spool of the dross processing apparatus of Fig 1;
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The dross processing apparatus 1 as illustrated in Figs 1 to 8 of the accompanying drawings comprises a vertical frame comprising a square shaped bottom frame portion 2 and a rectangular vertical frame portion 3 (Figs 1 an d 2). The bottom frame portion is provided with castor wheels 4. The lower end of the vertical frame portion is fixed to the bottom frame portion and the top of the vertical frame portion is provided with a platform 5. 6 is a semispherical reaction vessel provided with a pair of trunnions 7,7 (Figs 1, 2 and 3). Each of the trunnions is pivoted on a cross member 8 at each side of the vertical frame portion using clamp 9. The cross members are fixed to the vertical frame portion at an intermediate location thereof. The reaction vessel is also provided with two diametrically opposite discharge ports 10, 10 at the curvature at the bottom thereof in the proximity of the center thereof preferably at a distance of 40 to 55 cms from the center thereof. Each of the discharge ports is preferably 7-9 mm diameter in size. The reaction vessel is further provided with a handle 11 fixed to one of the trunnions. 12 is an electric motor mounted on an extension 5a of the platform with its shaft 13 directed horizontally. 14 is a speed reduction gear box mounted on the platform in the proximity of the electric motor with its input shaft 15 and output shaft 16 horizontally directed at right angle to each other . The input shaft 15 of the gear box is coupled to the motor shaft 13. 17 is an agitator up and down movably held aligned with respect to the reaction vessel (Figs 1, 2 and 4). The agitator shaft comprises an upper part 19 and lower part 20 provided with flanges 19a and 20a, respectively (Fig 4). The upper part and lower part of the agitator shaft are detachably fixed to each other by bolting (bolts not shown) the respective flanges. The agitator comprises a hollow semicircular member 21 fixed to
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the lower end of the lower part of the agitator shaft and corresponding to the inner surface of the reaction vessel (Figs 1, 2 and 4). 22a, 22b and 22c are three spaced vertical ribs disposed within the semicircular member and fixed thereto (Fig 4). 23, 23 are a pair of horizontal projections projecting from the middle rib in opposite directions perpendicular to the plane of the semicircular member and corresponding to the inner surface of the reaction vessel (Fig 4), 24 is a first bevel gear mounted on the output shaft of the gear box (Fig 2). 25 is a second bevel gear horizontally disposed on the platform and provided with a hub 26 projecting downwardly therefrom (Figs 1,2,5 and 6). The first bevel gear is in mesh with the second bevel gear 25 whose hub 26 is vertically rotatably held in an upright hollow support member 27 formed with a pair of flanges 27a and 27b at the bottom and top thereof. The support member is mounted on the platform by bolting (bolts not shown) the bottom flange 27a to the platform. The second bevel gear is supported against the top flange 27b. The hub of the second bevel gear is rotatable in the hollow support member against a bush bearing 28 located in the support member (Fig 7). The agitator shaft is provided with an oblong groove 29 partially along the upper end thereof (Figs 1 and 2). The second bevel gear and the hub thereof are provided with an oblong protrusion 30 along the inner surface thereof (Figs 5 and 6). The protrusion 30 corresponds to the oblong groove on the agitator shaft upper end. The agitator shaft is disposed in the second bevel gear and hub with the oblong groove engaged over the oblong protrusion such that the agitator shaft is movable up and down in the second bevel gear with the agitator. The up and down movement of the agitator shaft is guided by the oblong protrusion in the second bevel gear and the hub thereof. The agitator shaft and agitator rotate with the second bevel gear as the oblong groove on the agitator shaft upper
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end is engaged over the oblong protrusion in the second bevel gear and hub. A pair of spaced angular arms 32, 32 are vertically supported on the platform (Figs 1 and 2). 33 is a pulley rotatably held between the free ends of the arms and 34 is a wire rope running over the pulley and wound over a spool 35. One end of the wire is fixed to a clip 36 which in turn is fixed to the free end of the agitator shaft. The other end of the wire rope is fixed to the spool. The spool is rotatably held in a pair of brackets (not shown) laterally extending from either side of the top of the frame. The spool comprises a pair of circular end flanges 36a, 36b. The end flange 36a is provided with a handle 37 and a pair of diametrically opposite open slots 38, 38 at the circumference thereof (Fig 8). 39 is an oblong slider aligned with the circumference of the end flange 36a and horizontally slidably held to the vertical frame at the top thereof between oblong sections 40, 40 fixed to the vertical frame at the top thereof (Fig 8). One end of the oblong slider is adapted to engage in and disengage from the open slots at the circumference of the end flange 36a. The oblong slider is manually moved in and out of the open slots at the circumference of the end flange 36a sequentially. The other end of the oblong slider is provided with a tapered protruberance 41 for hand grip and manual operation thereof. The agitator is moved up and down in the second bevel gear and hub thereof with respect to the reaction vessel by rotating the spool holding the handle thereof and winding and unwinding the wire rope on the spool. The pulley rotates and facilitates the up and down travel of the agitator, which corresponds to the center to center circumferential distance between the open slots at the circumference of the end flange 36a. The rotation of the spool and winding and unwinding of the wire rope on the spool is arrested and the agitator is held at the upper and lower positions thereof by engaging the oblong slider in the respective
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open slot at the circumference of the end flange 36a.
During operation of the apparatus of the invention, drosses formed on the surfaces of metal melts in furnaces and at around 800 to 950°C are loaded into the reaction vessel. Exothermic compounds such as salts of potassium and sodium chlorides are added to the reaction vessel in order to increase the temperature of the dross mass. The agitator is lowered down into the reaction vessel by rotating the spool and unwinding the wire rope in one direction and is held in the lowered position by engaging the oblong slider in the respective open slot in the circumference of the end flange 36a. The agitator is rotated by switching on the motor. The first bevel gear rotates in the horizontal plane with the output shaft of the gear box and drives the second bevel gear in the vertical plane. The agitator rotates with the second bevel gear in the vertical plane thereby churning and stirring the dross in the reaction vessel. The RPM of the motor, gear ratio of the gear box and teeth ratio of the first bevel gear and second bevel gear are selected to give a rotational speed of 70 to 100 per minute to the agitator. Due to the geometry and configuration of the agitator, the dross is agitated and churned in all the directions disintegrating the dross mass into smaller particles effectively thereby increasing the release of liquid metal entrapped in the dross. Because of the semispherical geometry of the reaction vessel, the liquid metal flows down to the bottom of the vessel smoothly rapidly. As there are two discharge ports located at the curvature of the reaction vessel diametrically opposite, the liquid metal flows out from the reaction vessel rapidly thereby increasing the metal recovery. The centrifugal forces at the curvature of the reaction vessel is less as compared to that at the center of the reaction vessel. Due to the reduced
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centrifugal force and presence of the two discharge ports outflow of the liquid metal is further improved. Presence of two discharge ports also reduces the residence time of the liquid metal in the reaction vessel. Due to the rapid outflow of the liquid metal, choking of the discharge ports is prevented. The out flowing metal is collected in a pan (not shown) disposed below the discharge ports and processed further in known manner. On completion of the metal recovery, the motor is switched off and the agitator is raised from the reaction vessel by rotating the spool in the opposite direction and winding the rope on the spool. The agitator is held in the raised position by engaging the oblong slider in the respective oblong slot at the circumference of the end flange 36a. The spent dross or skull dross is emptied from the reaction vessel by tilting it about the pivot thereof by holding the respective handle. The agitator can be assembled to and dismantled from the upper part of the agitator shaft easily because of the bolt fit. Therefore, assembly and disassembly of the agitator for repairs or replacement thereof is easy and convenient and it is not necessary to dismantle the entire agitator from the vertical frame for such purpose. As the motor is mounted in the horizontal plane axial forces on the motor are reduced. Therefore, energy consumption by the motor is reduced. Vibration of the motor is also reduced thereby reducing the noise level of operation thereof. The strength requirement of the structural support of the motor is also reduced. The rope and pulley arrangement for raising and lowering the agitator is very simple in construction and operation and does not consume any energy. The construction of the dross processing apparatus as a whole is simplified and it is very convenient to operate it. Besides increasing metal recovery and preventing choking of the metal parts, the apparatus is also practically maintenance free. It consumes reduced energy and is cost effective and
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economical. Due to its portability the apparatus can be positioned close or away from the furnace as per convenience of the operator.
The vertical frame may be of a different construction/configuration. There can be more than two discharge ports in the reaction vessel. The rope and pulley arrangement can be of a different construction / configuration. The agitator can be of a different construction/configuration. The drive transmitting means can be of a different construction/configuration. Such constructional changes of the invention are obvious variations and are to be construed and understood to be within the scope of the invention.
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We claim :
1. A portable dross processing apparatus comprising a vertical frame provided with castor wheels at the bottom thereof and a platform at the top thereof, a semispherical reaction vessel pivotally mounted at an intermediate location in the vertical frame and provided with a handle and at least two diametrically opposite discharge ports at the curvature at the bottom thereof in the proximity of the center thereof, an electric motor mounted on the platform with its shaft directed horizontally, a speed reduction gear box mounted on the platform in the proximity of the electric motor with its input shaft and output shaft horizontally directed at right angle to each other, the input shaft of the gear box being coupled to the motor shaft, an agitator up and down movably held in the platform aligned with respect to the reaction vessel, drive transmitting means interconnecting the output shaft of the gear box and the agitator shaft to rotate the agitator in the vertical plane and a rope and pulley arrangement connected to the agitator for moving the agitator up and down.
2. A portable apparatus as claimed in claim 1, wherein the discharge ports are at a distance of 40 to 55 cms from the center of the reaction vessel and each of the discharge ports is 7-9mm diameter.
3. A portable apparatus as claimed in claim 1 or 2, wherein the agitator comprises a hollow semicircular member fixed to the lower end of the agitator shaft and corresponding to the inner surface of the reaction vessel, at least three spaced
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vertical ribs disposed within the semicircular member and fixed thereto and at least one pair of horizontal projections projecting from at least the middle rib in opposite directions perpendicular to the plane of the semicircular member and corresponding to the inner surface of the reaction vessel.
4. A portable apparatus as claimed in anyone of claims 1 to 3, wherein the agitator shaft is of two piece construction comprising an upper part and a lower part adapted to be detachably fitted to each other, the agitator being fixed to the lower end of the agitator shaft.
5. A portable apparatus as claimed in anyone of claims 1 to 4, wherein the vertical frame comprises a square shaped bottom frame portion provided with castor wheels and a rectangular vertical frame portion whose lower end is fixed to the bottom frame portion and upper end is provided with the platform.
6. A portable apparatus as claimed in anyone of claims 1 to 5, wherein the reaction vessel is provided with a paid of trunnions, each of the trunnions being pivoted on a cross member fixed to the vertical frame portion at an intermediate location at each side thereof, the handle of the reaction vessel being fixed to one of the trunnions
7. A portable apparatus as claimed in any one of claims 1 to 6, wherein the drive
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transmission means comprises a first bevel gear mounted on the output shaft of the gear box in mesh with a second bevel gear which is horizontally disposed and vertically rotatably supported on the platform, the agitator shaft being up and down movably held in the second bevel gear and being rotatable with the second bevel gear.
8. A portable apparatus as claimed in claim 7, wherein the second bevel gear is provided with a hub projecting downwardly therefrom, the hub being vertically rotatably held in an upright hollow support member formed with a pair of flanges one at the bottom and the other at the top thereof, the support member being mounted on the platform by bolting the bottom flange thereof to the platform and the second bevel gear being supported against the top flange of the support member, the agitator shaft being provided with an oblong groove partially along the upper end thereof and engaged over a correspondingly profiled oblong protrusion provided in the second bevel gear and the hub along the inner surface thereof, the up and down movement of the agitator shaft being guided by the oblong protrusion.
9. A portable apparatus as claimed in claim 8, wherein the second bevel gear is rotatably held in the support member over a bush bearing.
10. A portable apparatus as claimed in any one of claims 1 to 9, wherein the rope and pulley arrangement comprises a pair of spaced angular arms vertically supported
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on the platform, a pulley rotatably held between the free ends of the arms and a wire rope running over the pulley and wound over a spool, one end of the wire rope being fixed to the free end of the agitator shaft and the other end of the wire rope being fixed to the spool, the spool being rotatably held to the frame at the top thereof and comprising a pair of circular end flanges one of which is provided with a handle, said one end flange being further provided with a pair of diametrically opposite open slots at the circumference thereof and an oblong slider aligned with the circumference of the said one end flange and horizontally slidably held to the vertical frame at the top thereof, one end of the oblong slider being adapted to be engaged in and disengaged from the open slots in the said one end flange sequentially and the other end of the oblong slider being provided with a tapered protruberance for hand grip.
Dated this 13th day of December 2005.

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ABSTRACT
A portable dross processing apparatus (1). A vertical frame comprising a bottom portion (2) and a vertical portion (3) is provided with castor wheels (4) at the bottom thereof and a platform (5) at the top thereof. A semispherical reaction vessel (6) is pivotally mounted at an intermediate location in the vertical frame and provided with a handle (11) and at least two diametrically opposite discharge ports (10,10) at the curvature at the bottom thereof in the proximity of the center thereof. An electric motor (12) is mounted on the platform with its shaft (13) directed horizontally. A speed reduction gear box (14) is mounted on the platform in the proximity of the electric motor with its input shaft (15) and output shaft (16) horizontally directed at right angle to each other. The input shaft of the gear box is coupled to the motor shaft. An agitator (17) is up and down movably held in the platform aligned with respect to the reaction vessel. Drive transmitting means comprising a first bevel gear (24) in mesh with a second bevel gear (25) is provided to interconnect the output shaft of the gear box and the agitator shaft so as to rotate the agitator in the vertical plane. A rope and pulley arrangement comprising a wire rope (34) connected to the agitator and running over a pulley (33) and wound over a spool (35) is provided to move the agitator up and down (Fig 2).

PORTABLE DROSS PROCESSING APPARATUS

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