Title of Invention	"AN IN LINE PERMANENT MAGNETIC FILTER FOR REMOVAL OF WEAKLY MAGNETIC IMPURITIES FROM SLURRY"
Abstract	The invention relates to an inline permanent magnetic filter for removal of weakly magnetic impurities from slurry comprising a non - magnetic stainless steel housing () with inlet (2) and outlet (10) pipes with flanges and 3-way valves (5), said housing () is provided with a top plate ( 3) to which plurality of brass tube wells (6) are fixed and said brass tubes (6) are packed with filter matrix (8) and forms a well for sliding and location of permanent magnetic elements (4) which are fixed to a moving lid (7), the said lid is actuated by an actuator (9).

Title of Invention

"AN IN LINE PERMANENT MAGNETIC FILTER FOR REMOVAL OF WEAKLY MAGNETIC IMPURITIES FROM SLURRY"

Abstract

The invention relates to an inline permanent magnetic filter for removal of weakly magnetic impurities from slurry comprising a non - magnetic stainless steel housing () with inlet (2) and outlet (10) pipes with flanges and 3-way valves (5), said housing () is provided with a top plate ( 3) to which plurality of brass tube wells (6) are fixed and said brass tubes (6) are packed with filter matrix (8) and forms a well for sliding and location of permanent magnetic elements (4) which are fixed to a moving lid (7), the said lid is actuated by an actuator (9).

Full Text	BACKGROUND OF THE INVENTION: This invention relates to an inline permanent magnetic filter for removal of weakly magnetic impurities from slurry such as ilmenite, iron oxide and similar substances from wet slurries. PRIOR ART It is very common to use normal permanent magnet based traps. Alnico magnet elements are used for such permanent magnet based traps. The low intensity separators are also being used for a very long time in many process industries. Electro magnetic high intensity separators are used when reliable and high efficiency is to be ensured. With the advent of raw earth permanent magnets, the application range of low intensity magnetic filters has dramatically improved. It has become an economic alternative in medium intensity range. The advantages of such permanent magnet based systems are that it does not require any maintenance and has no operating cost component. The system is also flexible so that it can be designed for wide range of flow conditions. However, there are 'several disadvantages associated with the present system of permanent magnet traps using Alnico magnet elements is that the trapping efficiency is limited due to the basic magnetic strength of 4000 gaus. The disadvantages associated with low intensity separator used in process industries is that their efficiency is very low. Further disadvantages with the present system of electro-magnetic high intensity separators is that they are very costly. Finally, the disadvantages associated with the present system of low intensity rare earth permanent magnet separators and all other existing system is that their utility is restricted to only ferrous impurities and not useful for weakly magnetic materials. SUMMARY OF THE INVENTION: Therefore, the main object of the present invention is to provide a simple and effective means of removal of weakly magnetic impurities from wet slurries. Another objective is to extend the range of applicability of permanent magnet filters from removal of ferrous impurities to weakly magnetic impurities. Yet another objective is to take advantage of economically flexible design over wide range of flow conditions. This ensures that number of systems can be installed in many flow lines instead of single bulky electro magnet high intensity separator. Further object of the present invention is to eliminate the high cost bulky electromagnets. According to the present invention there is provided an in line permanent magnetic filter - for removal of weakly magnetic impurities from slurry comprising a non-magnetic stainless steel housing with inlet and outlet pipes with flanges and 3-way valves said housing is provided with a top plate to which plurality of brass tube are fixed and said brass tubes are packed with filter matrix and forms a well for sliding and location of permanent magnetic elements which are fixed to a moving lid the 'said lid is actuated by an actuator. The nature of the invention, its objective and further advantages residing in the same, will be apparent from the following description made with reference to non-limiting exemplary embodiments of the invention represented in the accompanying drawing. Figure 1 : Sectional view of the arrangement of the permanent magnet filter; Figure 2 : View of the magnet element arrangement. DESCRIPTION OF THE PREFERRED EMBODIMENT The system consists of a non-magnetic housing SS 304 (1) with inlet and outlet pipes with flanges (2). This is for easy installation in a liquid flow line. Three way valve (5) is interfaced at the inlet and outlet ends for diverting the flow of slurry and water during filtration and flush cycle. The housing has a top plate (3) to which brass tubes (6) are fixed. These tubes are specifically arranged so as to ensure proper and uniform distribution of slurry around these wells. This will facilitate effective interaction of magnetic impurities with the magnet elements. These tubes form a well for sliding and location of permanent magnetic elements (A) which are fixed to a moving plate (7). The magnetic elements (4) are high strength rare earth magnets specifically arranged for effective magnetic interaction with slurry flow and to provide background field to the matrix as well as magnetize ferrous impurities in slurry. The magnetic elements are provided with a brass sleeve for protection and cleaning. The moving plate is for withdrawing the magnetic elements from the well so that the filter region is free from magnetic field during flush cycle. This is facilitated by guide bars and has a fixed stroke length which is in excess of magnetic element length. This ensures complete removal of magnetic element from the filter volume and hence absence of background magnetic field for the filter matrix (8) packed inside the filter volume. The matrix is SS430 steel wool of 40 um diameter and it is loosely packed to a density of 1-2% for providing localized field gradients which enable the weakly magnetic material to get polarized and cling to the matrix In the presence of permanent magnets(4), the steel wool of the filter matrix (8) gets magnetized and a field gradient is established in the gap between wool surfaces. When paramagnetic impurities pass through these gaps, they experience a magnetic polarization and cling to steel wool of the filter matrix (8) surface and hence trapping. On withdrawing the magnet element (4) full above the top plate (7), the wool looses back ground magnetic field and hence looses magnetism. Hence the field gradient in the gap is lost. The paramagnetic impurities are no longer held to the wool surface of the filter matrix (8) and hence easily flushed out. The permanent magnet filter device can easily be installed and operate unattended with low cost programmable logic controllers for sequentially operating slurry and water flow valves and actuators. The dimensions of the system developed for illustration is as follows Housing SS 304,130 mm outer diameter, 160 mm long Brass well : 28 mm ID, 0.7 mm wall thickness, 134 mm long 5 nos distributed at 75 mm pcd as shown in Figure Inlet/outlet pipes 2" Valve : 3 way SS Ball valve for slurry/water flow Magnet element: 25 mm dia,Nd Fe B magnets housed in a brass sleeve, 5 Nos Actuator: Stroke length : 150 mm Filter matrix : 2% packing, SS 430 steel wool. The separation performance of the system is illustrated by the typical result as given below. Typical Experimental trials : Test sample: Calcite ore sample with CaCO3 - 83% and traces of iron impurities, Fe 1.14% Test procedure:Calcite sample with an average particle size of 75 was prepared in the form of 10% slurry. This was pumped through the permanent magnetic filter using a peristaltic pump. The flow rate was maintained at 3.5 Ipm. The feed cycle was fixed at 10 minutes. This was followed by a rinse cycle with water at a flow rate of 3 Ipm for 10 minutes.Then the top plate with "magnet elements was with drawn from the filter housing to ensure no magnetic field present in the processing area. This was followed by a wash cycle with high pressure water where by the trapped magnetic materials were removed. The table shows the impurity levels of calcite before and after filtration. TABLE 1 (Table Removed) The iron oxide level could be substantially removed from 1.14% to 0.61% indicating that the present invention is capable of removing paramagnetic impurities. The foregoing description shows that the present invention is a simple and highly efficient method of removing paramagnetic impurities at medium intensity range. This allows for adaptation in automated mode by incorporating pneumatic actuator for the movement of magnet elements in and out of the well and solenoid valves for controlling the flow of slurryand water and the entire cycle sequentially operated using low cost programable controllers. The invention described herein above is a reation to a non-limiting embodiment and as described by the accompanying claims. WE CLAIM 1. An inline permanent magnetic filter for removal of weakly magnetic . impurities from slurry comprising a non-magnetic stainless steel housing (1) with inlet (2) and outlet (10) pipes with flanges and 3-way valves (5), said housing (1) is provided with a top plate (3) to which plurality of brass tube wells (6) are fixed and said brass tubes (6) are packed with filter matrix (8) and forms a well for sliding and location of permanent magnetic elements (4) which are fixed to a moving lid (7), the said lid is actuated by an actuator (9). 2. An inline permanent magnet filter as claimed in claim 1, wherein said magnetic elements are provided with a brass sleeve assembly for protection and cleaning. 3. An inline permanent magnet filter as claimed in claim 1, wherein said brass tubes (6) form a well for sliding and location of said magnetic elements fixed to said moving lid and said tubes are arranged to ensure uniform distribution of slurry around these wells. 4. An inline permanent magnet filter as claimed in claim 1, wherein said filter matrix (8) is SS 430 steel wool of 40 um diameter and it is loosely packed to a density of 1-2%. 5. An inline permanent magnet filter as claimed in claim 1 & 2, wherein said magnetic elements are of high strength rare earth magnets specifically arranged for effective magnetic interaction with slurry flow. 6. An inline permanent magnet filter as claimed in claim 1, wherein the said filter device can be operated unattended with P low cost programmable logic controllers for sequentially operating slurry and water flow valves (5) and actuators (9). 7. An inline permanent magnetic filter for removal of weakly magnetic impurities from slurry as herein described and illustrtated.

Full Text

BACKGROUND OF THE INVENTION:
This invention relates to an inline permanent magnetic filter for
removal of weakly magnetic impurities from slurry such as
ilmenite, iron oxide and similar substances from wet slurries.
PRIOR ART
It is very common to use normal permanent magnet based traps.
Alnico magnet elements are used for such permanent magnet based
traps.
The low intensity separators are also being used for a very long
time in many process industries.
Electro magnetic high intensity separators are used when reliable
and high efficiency is to be ensured.
With the advent of raw earth permanent magnets, the application
range of low intensity magnetic filters has dramatically improved. It has become an economic alternative in medium
intensity range. The advantages of such permanent magnet based systems are that it does not require any maintenance and has no operating cost component. The system is also flexible so that it can be designed for wide range of flow conditions.
However, there are 'several disadvantages associated with the present system of permanent magnet traps using Alnico magnet elements is that the trapping efficiency is limited due to the basic magnetic strength of 4000 gaus.
The disadvantages associated with low intensity separator used in process industries is that their efficiency is very low. Further disadvantages with the present system of electro-magnetic high intensity separators is that they are very costly.
Finally, the disadvantages associated with the present system of low intensity rare earth permanent magnet separators and all other existing system is that their utility is restricted to only ferrous impurities and not useful for weakly magnetic materials.
SUMMARY OF THE INVENTION:
Therefore, the main object of the present invention is to provide a simple and effective means of removal of weakly magnetic impurities from wet slurries.
Another objective is to extend the range of applicability of permanent magnet filters from removal of ferrous impurities to weakly magnetic impurities.
Yet another objective is to take advantage of economically flexible design over wide range of flow conditions. This ensures that number of systems can be installed in many flow lines instead of single bulky electro magnet high intensity separator.
Further object of the present invention is to eliminate the high cost bulky electromagnets.
According to the present invention there is provided an in line permanent magnetic filter - for removal of weakly magnetic impurities from slurry comprising a non-magnetic stainless steel housing with inlet and outlet pipes with flanges and 3-way valves said housing is provided with a top plate to which plurality of brass tube are fixed and said brass tubes are packed with filter matrix and forms a well for sliding and location of permanent magnetic elements which are fixed to a moving lid the 'said lid is actuated by an actuator.
The nature of the invention, its objective and further advantages residing in the same, will be apparent from the following
description made with reference to non-limiting exemplary embodiments of the invention represented in the accompanying drawing.
Figure 1 : Sectional view of the arrangement of
the permanent magnet filter; Figure 2 : View of the magnet element arrangement.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The system consists of a non-magnetic housing SS 304 (1) with inlet and outlet pipes with flanges (2). This is for easy installation in a liquid flow line. Three way valve (5) is interfaced at the inlet and outlet ends for diverting the flow of slurry and water during filtration and flush cycle. The housing has a top plate (3) to which brass tubes (6) are fixed. These tubes are specifically arranged so as to ensure proper and uniform distribution of slurry around these wells. This will facilitate effective interaction of magnetic impurities with the magnet elements. These tubes form a well for sliding and location of permanent magnetic elements (A) which are fixed to a moving plate (7). The magnetic elements (4) are high strength rare earth magnets specifically arranged for effective magnetic interaction with slurry flow and to provide background field to the matrix as well as magnetize ferrous impurities in slurry. The magnetic elements are provided with a brass sleeve for protection and cleaning. The moving plate is for withdrawing the magnetic elements from the well so that the filter region is free from magnetic field during flush cycle. This is facilitated by guide bars and has a fixed stroke length which is in excess of magnetic element length. This ensures complete removal of magnetic element from the filter volume and hence absence of background magnetic field for the filter matrix (8) packed inside the filter volume. The matrix is SS430 steel wool of 40 um diameter and it is loosely packed to a density of 1-2% for providing localized field gradients which enable the weakly magnetic material to get polarized and cling to the matrix
In the presence of permanent magnets(4), the steel wool of the filter matrix (8) gets magnetized and a field gradient is established in the gap between wool surfaces. When paramagnetic impurities pass through these gaps, they experience a magnetic polarization and cling to steel wool of the filter matrix (8) surface and hence trapping. On withdrawing the magnet element (4) full above the top plate (7), the wool looses back ground magnetic field and hence looses magnetism. Hence the field gradient in the gap is lost. The paramagnetic impurities are no longer held to the wool surface of the filter matrix (8) and hence easily flushed out. The permanent magnet filter device can easily be installed and operate unattended with low cost programmable logic controllers for sequentially operating slurry and water flow valves and actuators.
The dimensions of the system developed for illustration is as
follows
Housing SS 304,130 mm outer diameter, 160 mm long
Brass well : 28 mm ID, 0.7 mm wall thickness, 134 mm long
5 nos distributed at 75 mm pcd as shown in Figure
Inlet/outlet pipes 2"
Valve : 3 way SS Ball valve for slurry/water flow
Magnet element: 25 mm dia,Nd Fe B magnets housed in a brass
sleeve, 5 Nos
Actuator: Stroke length : 150 mm Filter matrix : 2% packing, SS 430 steel wool.
The separation performance of the system is illustrated by the
typical result as given below.
Typical Experimental trials :
Test sample: Calcite ore sample with CaCO3 - 83% and traces
of iron impurities, Fe 1.14%
Test procedure:Calcite sample with an average particle size of 75 was prepared in the form of 10% slurry. This was pumped through the permanent magnetic filter using a peristaltic pump. The flow rate was maintained at 3.5 Ipm. The feed cycle was fixed at 10 minutes. This was followed by a rinse cycle with water at a flow rate of 3 Ipm for 10 minutes.Then the top plate
with "magnet elements was with drawn from the filter housing to ensure no magnetic field present in the processing area. This was followed by a wash cycle with high pressure water where by the trapped magnetic materials were removed. The table shows the impurity levels of calcite before and after filtration.
TABLE 1 (Table Removed)
The iron oxide level could be substantially removed from 1.14% to 0.61% indicating that the present invention is capable of removing paramagnetic impurities.
The foregoing description shows that the present invention is a simple and highly efficient method of removing paramagnetic impurities at medium intensity range. This allows for adaptation in automated mode by incorporating pneumatic actuator for the movement of magnet elements in and out of the well and solenoid valves for controlling the flow of slurryand water and the entire cycle sequentially operated using low cost programable controllers.
The invention described herein above is a reation to a non-limiting embodiment and as described by the accompanying claims.

WE CLAIM
1. An inline permanent magnetic filter for removal of weakly magnetic . impurities from slurry comprising a non-magnetic stainless steel housing (1) with inlet (2) and outlet (10) pipes with flanges and 3-way valves (5), said housing (1) is provided with a top plate (3) to which plurality of brass tube wells (6) are fixed and said brass tubes (6) are packed with filter matrix (8) and forms a well for sliding and location of permanent magnetic elements (4) which are fixed to a moving lid (7), the said lid is actuated by an actuator (9).
2. An inline permanent magnet filter as claimed in claim 1,
wherein said magnetic elements are provided with a brass sleeve
assembly for protection and cleaning.
3. An inline permanent magnet filter as claimed in claim
1, wherein said brass tubes (6) form a well for sliding and
location of said magnetic elements fixed to said moving lid
and said tubes are arranged to ensure uniform distribution of
slurry around these wells.

4. An inline permanent magnet filter as claimed in claim 1,
wherein said filter matrix (8) is SS 430 steel wool of 40 um
diameter and it is loosely packed to a density of 1-2%.
5. An inline permanent magnet filter as claimed in claim 1
& 2, wherein said magnetic elements are of high strength rare
earth magnets specifically arranged for effective magnetic
interaction with slurry flow.
6. An inline permanent magnet filter as claimed in claim 1,
wherein the said filter device can be operated unattended
with P low cost programmable logic controllers for sequentially
operating slurry and water flow valves (5) and actuators (9).
7. An inline permanent magnetic filter for removal of weakly magnetic impurities from slurry as herein described and illustrtated.

Documents:

3459-del-1998-abstract.pdf

3459-del-1998-claims.pdf

3459-del-1998-correspondence-others.pdf

3459-del-1998-correspondence-po.pdf

3459-del-1998-description (complete).pdf

3459-del-1998-drawings.pdf

3459-del-1998-form-1.pdf

3459-del-1998-form-13.pdf

3459-del-1998-form-19.pdf

3459-del-1998-form-2.pdf

3459-del-1998-form-4.pdf

3459-del-1998-gpa.pdf

« Previous Patent

Next Patent »

Patent Number

215307

Indian Patent Application Number

3459/DEL/1998

PG Journal Number

11/2008

Publication Date

14-Mar-2008

Grant Date

25-Feb-2008

Date of Filing

19-Nov-1998

Name of Patentee

BHARAT HEAVY ELECTRICALS LTD.

Applicant Address

BHEL HOUSE, SIRI FORT, NEW DELHI-110049, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	GOPALAN SWAMINATHAN	BHARAT HEAVY ELECTRICALS LIMITED, (A GOVT. OF INDIA UNDERTAKING), CORPORATE RESEARCH AND DEVELOPMENT, VIKASNAGAR, HYDERABAD 500 593, INDIA.

PCT International Classification Number

B01D 35/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA