Title of Invention	"AN IMPROVED SCREEN FOR UNIFORMLY FEEDING RELATIVELY LARGE COKE LUMPS INTO A CRUSHING MACHINE"
Abstract	An improved screen for uniformly feeding relatively large coke lumps into a crushing machine, the screen (1") comprising a number of metallic rods (1"A) lying along the length and a number of parallelly disposed metallic rods (1"B) lying across the width of the screen, characterised in that the said rods (1"A) lying along the length are divergent with respect to the central longitudinal line (1"B) from the receiving end (1"C) to the delivery end (1"D) of the screen, and that all joints of the rods (1"A and 1"B) forming the screen are made by voiding. Reference: Figure 2 of the accompanying drawings.

Title of Invention

"AN IMPROVED SCREEN FOR UNIFORMLY FEEDING RELATIVELY LARGE COKE LUMPS INTO A CRUSHING MACHINE"

Abstract

An improved screen for uniformly feeding relatively large coke lumps into a crushing machine, the screen (1") comprising a number of metallic rods (1"A) lying along the length and a number of parallelly disposed metallic rods (1"B) lying across the width of the screen, characterised in that the said rods (1"A) lying along the length are divergent with respect to the central longitudinal line (1"B) from the receiving end (1"C) to the delivery end (1"D) of the screen, and that all joints of the rods (1"A and 1"B) forming the screen are made by voiding. Reference: Figure 2 of the accompanying drawings.

Full Text	The present invention relates to an improved screen for uniformly feeding relatively large coke lumps into a crushing machine. The invention relates more particularly to a screen in which the metallic rods disposed parallelly along the length of an existing screen are arranged diverging with respect to the central longitudinal line from the receiving end to the delivery end thereof. Wharf cokes obtained from a coke oven contain coke lumps of various sizes, are carried over conveyor belts and allowed to drop from the delivery end of the belts onto the receiving end of an inclined screen via a chute. A conventional screen is formed of a number of parallelly disposed metallic rods of typical diameter 40 mm along the length of the same having a typical gap of 80 mm between the adjacent rods, so that the coke lumps of size smaller than 80 mm fall underneath the screen and those of size larger than 80 mm move downward over the inclined screen and fall from the delivery end of the screen into the gap between the two toothed rolls of a crushing machine which is disposed parallelly to the width of the screen below the delivery end thereof for crushing the same into coke lumps of size smaller than 80 mm. The chute used for transferring the coke lumps from the delivery end of the conveyor belts to the receiving end of the screen being of width converging towards the screen, the distribution of coke lumps across the screen width is non-uniform, being concentrated at the central part thereof before the coke lumps are delivered onto the crushing machine. The said rods being parallelly disposed along the length of the existing screen the non-uniformity in the distribution of coke lumps is maintained at the delivery end of the screen. As a result most of the crushing action on coke lumps is performed at the central part only of the two toothed rolls of the crushing machine, causing thereby a rapid wearing of the teeth there and much reduced wearing of the teeth lying at the two end parts of the toothed rolls, requiring replacement of the toothed rolls of the crushing machine after a relatively short period and hence increasing the cost of maintenance of the crushing machine appreciably. The objective of the present invention is to provide a screen by using which the non-uniformity of coke lump distribution across the width of the screen is removed to a large extent before delivery of the same into the crushing machine and thereby the working life of the toothed rolls of the crushing machine is extended appreciably because of uniform wearing of teeth of the rolls over almost the entire length thereof. Thus the invention provides an improved screen for uniformly feeding relatively large coke lumps into the gap between the two toothed rolls of a crushing machine, the screen comprising a number of metallic rods lying along the length and a number of parallelly disposed metallic rods lying across the width of the screen, characterised in that the said rods lying along the length are divergent With respect to the central longitudinal line from the receiving end to the delivery end of the screen, and that all joints of the rods forming the screen are made by welding. The invention is described fully and particularly without restricting its scope in any manner with reference to the accompanying drawings in which - Figure 1 shows a sketch of a device having an existing screen for crushing relatively large coke lumps; Figure 2 shows a plan view of the invented screen for use in the device shown in Fig. 1 in replacement of the existing screen. Referring to Fig. 1, the existing screen (1) comprises parallelly disposed rods (1A) lying along the length and parallelly disposed rods (1B) lying across the width of the screen, and is mounted with its receiving end (1C) lying below the delivery end (2B) of chute (2) and its delivery end (1D) lying above the gap (4A) between the two toothed rolls (4) of a crushing machine. The receiving end (2A) of chute (2) is placed below the delivery end (3A) of the conveyor belt (3) carrying coke lumps (5) from a coke oven (not shown). The directions of the movement of coke lumps in the system are indicated by arrows. The width of chute (2) is convergent from its receiving end (2A) to its delivery end (2B). Referring to Fig. 2 the invented screen (1’) comprises a number of rods (1'A) lying along its length, which are divergent with respect to the central longitudinal line (1'B) from the receiving end (1'C) to the delivery end (1'D) of the screen and a number of rods (1'B) lying along the width of the screen, which are parallel to one another like those of the existing screen. The constructional parameters of the particular embodiment of the invented screen (11) shown in Fig. 2 are presented in Table I. The rods used may be of circular, rectangular or square cross section. In the case of rods of rectangular or square cross section, the sharp corners are rounded off. Comparative performance of the existing and the invented screens has been studied in a steel plant over a period. It has been observed that the working life of the toothed rolls of the crushing machine is extended from 3-4 months as obtained by using the existing screen to 5-6 months by using the invented screen. The proportion by weight of coke lumps of size larger than 100 ram has been found to be around 70% after crushing by using the invented screen as against around 35% by using the existing screen, showing thereby an appreciable increase in the crushing efficiency of the machine attained by using the invented screen. Table,, I : Typical constructional Parameters of the Invented Screen. (i) Length 2000 mm (ii) Width 1480 mm (iii) number of longitudinal rods d'A) 10 (iv) number of transverse rods (1 'B) 2 (v) diameter of each of rods (1'A and 1'B) 40 mm (vi) gap between adjacent longitudinal rods (a) at the receiving end (1*0) 90 mm (b) at the delivery end (1'D) 115 mm (vii) gap between the transverse rods (1'B) 650 mm (viii) gap between the receiving end d'C) and adjacent transverse rod (1'B) 650mm (ix) gap between the delivery end (1'D) and adjacent transverse rod d'B) 650mm (x) all joints are made by welding. We Claim :- 1. An Improved screen for uniformly feeding relatively large coke lumps into a crushing machine, the screen (1') comprising a number of metallic rods (1'A) lying along the length and a number of pa rail ally disposed metallic rods (1'B) lying across the width of the screen, characterised in that the said rods (1'A) lying along the length are divergent with respect to the central longitudinal line (1'B) from the receiving end (1'C) to the delivery end (1'D) of the screen, and that all joints of the rods (1'A and 1'B) forming the screen are made by welding. 2. The screen as claimed in claim 1, which is 2000 mm in length and 1480 ma in width. 3. The screen as claimed in claim 1, wherein the rods (1'A) are each of diameter 40 4. The screen as claimed in claims 1 to 3, wherein the number of rods (1'A) lying along the length of the screen is 10. 5. The screen as claimed in claim 4, wherein the rods (1'A) lying along the length of the screen are disposed with a gap between adjacent rods of 90 mm at receiving end (1'C) and 115 mm at the delivery end (1'D) of the screen. 6. An improved screen for uniformly feeding relatively large coke lumps into a crushing machine, substantially as herein described and illustrated in the accompanying drawings.

Full Text

The present invention relates to an improved screen for uniformly feeding relatively large coke lumps into a crushing machine.
The invention relates more particularly to a screen in which the metallic rods disposed parallelly along the length of an existing screen are arranged diverging with respect to the central longitudinal line from the receiving end to the delivery end thereof.
Wharf cokes obtained from a coke oven contain coke lumps of various sizes, are carried over conveyor belts and allowed to drop from the delivery end of the belts onto the receiving end of an inclined screen via a chute. A conventional screen is formed of a number of parallelly disposed metallic rods of typical diameter 40 mm along the length of the same having a typical gap of 80 mm between the adjacent rods, so that the coke lumps of size smaller than 80 mm fall underneath the screen and those of size larger than 80 mm move downward over the inclined screen and fall from the delivery end of the screen into the gap between the two toothed rolls of a crushing machine which is disposed parallelly to the width of the screen below the delivery end thereof for crushing the same into coke lumps of size smaller than 80 mm.
The chute used for transferring the coke lumps from the delivery end of the conveyor belts to the receiving end of the screen being of width converging towards the screen, the distribution of coke lumps across the screen width is non-uniform, being concentrated at the central part thereof before

the coke lumps are delivered onto the crushing machine. The said rods being parallelly disposed along the length of the existing screen the non-uniformity in the distribution of coke lumps is maintained at the delivery end of the screen. As a result most of the crushing action on coke lumps is performed at the central part only of the two toothed rolls of the crushing machine, causing thereby a rapid wearing of the teeth there and much reduced wearing of the teeth lying at the two end parts of the toothed rolls, requiring replacement of the toothed rolls of the crushing machine after a relatively short period and hence increasing the cost of maintenance of the crushing machine appreciably.
The objective of the present invention is to provide a screen by using which the non-uniformity of coke lump distribution across the width of the screen is removed to a large extent before delivery of the same into the crushing machine and thereby the working life of the toothed rolls of the crushing machine is extended appreciably because of uniform wearing of teeth of the rolls over almost the entire length thereof.
Thus the invention provides an improved screen for uniformly feeding relatively large coke lumps into the gap between the two toothed rolls of a crushing machine, the screen comprising a number of metallic rods lying along the length and a number of parallelly disposed metallic rods lying across the width of the screen, characterised in that the said rods lying along the length are divergent With respect to the central longitudinal line from the receiving end to the delivery end of the screen, and that all

joints of the rods forming the screen are made by welding.
The invention is described fully and particularly without restricting its scope in any manner with reference to the accompanying drawings in which -
Figure 1 shows a sketch of a device having an existing screen for crushing relatively large coke lumps;
Figure 2 shows a plan view of the invented screen for use in the device shown in Fig. 1 in replacement of the existing screen.
Referring to Fig. 1, the existing screen (1) comprises parallelly disposed rods (1A) lying along the length and parallelly disposed rods (1B) lying across the width of the screen, and is mounted with its receiving end (1C) lying below the delivery end (2B) of chute (2) and its delivery end (1D) lying above the gap (4A) between the two toothed rolls (4) of a crushing machine. The receiving end (2A) of chute (2) is placed below the delivery end (3A) of the conveyor belt (3) carrying coke lumps (5) from a coke oven (not shown). The directions of the movement of coke lumps in the system are indicated by arrows. The width of chute (2) is convergent from its receiving end (2A) to its delivery end (2B).
Referring to Fig. 2 the invented screen (1’) comprises a number of rods (1'A) lying along its length, which are divergent with respect to the central longitudinal line (1'B) from the receiving end (1'C) to the delivery end (1'D) of the screen and a number of rods (1'B) lying along the width of the

screen, which are parallel to one another like those of the existing screen. The constructional parameters of the particular embodiment of the invented screen (11) shown in Fig. 2 are presented in Table I. The rods used may be of circular, rectangular or square cross section. In the case of rods of rectangular or square cross section, the sharp corners are rounded off.
Comparative performance of the existing and the invented screens has been studied in a steel plant over a period. It has been observed that the working life of the toothed rolls of the crushing machine is extended from 3-4 months as obtained by using the existing screen to 5-6 months by using the invented screen.
The proportion by weight of coke lumps of size larger than 100 ram has been found to be around 70% after crushing by using the invented screen as against around 35% by using the existing screen, showing thereby an appreciable increase in the crushing efficiency of the machine attained by using the invented screen.

Table,, I : Typical constructional Parameters
of the Invented Screen.
(i) Length 2000 mm
(ii) Width 1480 mm
(iii) number of longitudinal rods d'A) 10
(iv) number of transverse rods (1 'B) 2
(v) diameter of each of rods (1'A and 1'B) 40 mm
(vi) gap between adjacent longitudinal rods
(a) at the receiving end (1*0) 90 mm
(b) at the delivery end (1'D) 115 mm
(vii) gap between the transverse rods (1'B) 650 mm
(viii) gap between the receiving end d'C) and
adjacent transverse rod (1'B) 650mm
(ix) gap between the delivery end (1'D) and
adjacent transverse rod d'B) 650mm
(x) all joints are made by welding.

We Claim :-
1. An Improved screen for uniformly feeding relatively
large coke lumps into a crushing machine, the screen (1')
comprising a number of metallic rods (1'A) lying along the
length and a number of pa rail ally disposed metallic rods (1'B)
lying across the width of the screen, characterised in that
the said rods (1'A) lying along the length are divergent with
respect to the central longitudinal line (1'B) from the
receiving end (1'C) to the delivery end (1'D) of the screen,
and that all joints of the rods (1'A and 1'B) forming the
screen are made by welding.
2. The screen as claimed in claim 1, which is 2000 mm
in length and 1480 ma in width.
3. The screen as claimed in claim 1, wherein the rods
(1'A) are each of diameter 40

4. The screen as claimed in claims 1 to 3, wherein the
number of rods (1'A) lying along the length of the screen is
10.
5. The screen as claimed in claim 4, wherein the rods
(1'A) lying along the length of the screen are disposed with
a gap between adjacent rods of 90 mm at receiving end (1'C)
and 115 mm at the delivery end (1'D) of the screen.

6. An improved screen for uniformly feeding relatively large coke lumps into a crushing machine, substantially as herein described and illustrated in the accompanying drawings.

Documents:

3064-del-1998-abstract.pdf

3064-del-1998-claims.pdf

3064-del-1998-correspondence-others.pdf

3064-del-1998-correspondence-po.pdf

3064-del-1998-description (complete).pdf

3064-del-1998-drawings.pdf

3064-del-1998-form-1.pdf

3064-del-1998-form-13.pdf

3064-del-1998-form-19.pdf

3064-del-1998-form-2.pdf

3064-del-1998-gpa.pdf

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Patent Number

215627

Indian Patent Application Number

3064/DEL/1998

PG Journal Number

11/2008

Publication Date

14-Mar-2008

Grant Date

28-Feb-2008

Date of Filing

20-Oct-1998

Name of Patentee

STEEL AUTHORITY OF INDIA LIMITED

Applicant Address

RESEARCH & DEVELOPEMENT CENTRE, FOR IRON & STEEL, ISPAT BHAWAN, LODI ROAD, NEW DELHI-110003, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	ASIM KUMAR DAS	RDCIS, SAIL, RANCHI - 834 002, INDIA
2	LAKSHMANAN PARTHSARATHY	RDCIS, SAIL, RANCHI - 834 002, INDIA
3	MITHILESH KUMAR SHARMA	RDCIS, SAIL, RANCHI - 834 002, INDIA
4	BISWAJIT ROY	RDCIS, SAIL, RANCHI - 834 002, INDIA

PCT International Classification Number

B02C 23/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA