Classifying – separating – and assorting solids – Sorting special items – and certain methods and apparatus for... – Separating means
Reexamination Certificate
2000-08-02
2001-10-23
Walsh, Donald P. (Department: 3653)
Classifying, separating, and assorting solids
Sorting special items, and certain methods and apparatus for...
Separating means
C209S606000, C209S617000, C209S618000, C209S659000, C209S660000, C209S667000
Reexamination Certificate
active
06305553
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to roller screens and, more particularly, to a system for adjusting the gap between adjacent rolls of the screen.
BACKGROUND OF THE INVENTION
The screens are used especially in the mining industry for classifying pellets as to size. A series of motor-driven parallel rolls are mounted on a bed frame with specific gaps between the individual rolls. The screen is inclined and can be made of a single roller deck or a double roller deck. The double roller deck is composed of an upper and a lower deck and its function is described below. The pellets are discharged onto the upper deck. All pellets having a larger size than the upper deck roll gap (oversized pellets) are transported to the end of the upper deck. All pellets having a smaller size than the upper deck roll gap are passing through these gaps onto the rolls of the lower deck. All pellets having a larger size than the lower deck roll gap (correct size pellets) are transported to the end of the lower deck. All pellets having a smaller size than the lower deck roll gap (undersized pellets or fines) are passing through these gaps. The roll surface becomes pitted and worn due to abrasion produced by the pellets and, therefore, the roll gap must be adjusted from time to time. The roll gaps may also need to be adjusted upon different pellet sizes required and specified by any specific end customer. This adjustment is conventionally a manual operation requiring bolting and unbolting of the individual rolls pillow blocks and adjustment of the gap by means of wedges or gauges inserted between the rolls at each end of the same. This is a time consuming operation.
OBJECTS OF THE INVENTION
The main object of the present invention is to provide a gapping system which is more convenient to operate and will considerably decrease the time necessary for roll gap adjustment and increase the precision of this adjustment.
Another object of the present invention is to provide a gapping system of the character described which can be remotely controlled and which can be either partially or fully automated.
Still another object of the present invention is to provide a gapping system that allows for adjusting either one, a plurality or all of the gaps between adjacent rolls at a time.
A further object of the present invention is to provide a method for rapidly and accurately adjusting the gaps between adjacent rolls of a roller screen apparatus.
SUMMARY OF THE INVENTION
According to one aspect of the present invention, there is provided a roller screen gapping system for a roller screen including a series of spaced parallel rolls mounted on pillow blocks at each end thereof, said pillow blocks slidable along respective bed plates transversely of the roll axes to adjust the gap between adjacent rolls, said system comprises biasing members to clamp said pillow blocks on said bed plates, unclamping cylinders carried by each pillow block and exerting an unclamping action on said bed plate to unclamp said pillow blocks for lateral sliding, gapping cylinders carried by each pillow block adapted to contact an adjacent pillow block to adjust the gap between adjacent rolls and a common push cylinder mounted on each of said bed plates and adapted to push all the pillow blocks against a fixed pillow block.
Preferably, each one of said pillow blocks supporting an end of a shaft of a respective one of said rolls and including a top section adapted to rotatably support the end of said shaft and a base section rigidly mounted onto said bed plate, said top section being slidably mounted onto said base section and frictionally retained thereon by a shoulder bolt with interposition of a biasing device, said top section being allowed to slightly slide along the axial direction of said shaft, thereby accounting for small axial displacement of said roll and said shaft caused by expansion and contraction of the latter under temperature changes.
Preferably, said biasing device being a belleville washer.
Preferably, said cylinders are hydraulic cylinders connected to a hydraulic control circuit, said biasing members being spring biased bolts.
Alternatively, said gapping cylinders are adapted to maximize the gap between adjacent of said rolls, said system further comprising a plurality of spacer members each of a specific thickness adapted to set the gap between said adjacent rolls.
Preferably, said biasing members being spring biased bolts.
Alternatively, each of said pillow blocks further carries an adjustment member adapted to be displaced to and from said respective pillow block to adjust a relative zero gap between adjacent of said pillow blocks corresponding to a zero gap between respective of said rolls.
Preferably, said biasing members being spring biased bolts and said adjustment member being adjustment screws.
Preferably, each of said adjustment members further include an adjustment lock to releasably lock said respective adjustment screw in position.
According to another aspect of the present invention, there is provided a method for adjusting a gap between respective adjacent rolls of a roller screen apparatus using a roller screen gapping system as defined above, said method comprises the steps of:
a) actuating said unclamping cylinders;
b) actuating said common push cylinders to push all of said pillow blocks against said fixed pillow block to set a zero gap condition of at least one of said rolls to be displaced, while said gapping cylinders of said at least one roll to be displaced being allowed to retract;
c) actuating said gapping cylinders of said at least one roll by a precise amount to obtain a required respective gap between the latter and the respective next of said rolls, while said common cylinders being allowed to partially retract; and
d) de-actuating said unclamping cylinders to allow for the clamping of said pillow blocks to respective of said bed plates.
Preferably, steps b) and c) being repeated before step d) for each of said respective gap to be adjusted.
Alternatively, the method comprises the steps of:
a) actuating said unclamping cylinders;
b) actuating said gapping cylinders to push all of said pillow blocks away from adjacent of said pillow blocks to maximize said gap between adjacent of aid rolls, while said common push cylinders being allowed to retract;
c) placing said spacer members between respective said adjacent rolls;
d) actuating said common push cylinders to displace all of said pillow blocks toward said fixed pillow block to ensure each of said spacer members being touched by two adjacent of said rolls, while said gapping cylinders being allowed to retract;
e) de-actuating said unclamping cylinders to allow for the clamping of said pillow blocks to respective of said bed plates; and
f) removing all of said spacer members.
Preferably, the method further comprises, after steps b) and c) the step of, respectively:
b′) de-actuating said unclamping cylinders to allow for the clamping of said pillow blocks to respective of said bed plates; and
c′) actuating said unclamping cylinders.
Alternatively, the method comprises the steps of:
a) actuating said unclamping cylinders;
b) actuating said gapping cylinders to push all of said pillow blocks away from adjacent of said pillow blocks to maximize said gap between adjacent of said rolls, while said common push cylinders being allowed to retract;
c) placing said spacer members between respective said adjacent pillow blocks next to said respective adjustment member;
d) actuating said common push cylinders to displace all of said pillow blocks toward said fixed pillow block to ensure each of said spacer members being touched by two adjacent of said pillow blocks, while said gapping cylinders being allowed to retract; and
e) de-actuating said unclamping cylinders to allow for the clamping of said pillow blocks to respective of said bed plates.
Preferably, the method further comprises, before the step a) the steps of:
i) actuating said unclamping cylinders;
ii) actuating said gapping cylinders to push all of said pillow block
Beauchaine Mark J.
Walsh Donald P.
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