Classifying – separating – and assorting solids – Sifting – Plane sifters
Reexamination Certificate
1998-09-23
2001-01-09
Walsh, Donald P. (Department: 3653)
Classifying, separating, and assorting solids
Sifting
Plane sifters
C209S331000, C209S375000, C198S530000, C198S540000, C198S550010, C198S566000
Reexamination Certificate
active
06170670
ABSTRACT:
TECHNICAL FIELD
The present invention pertains to methods of and apparatus for feeding various kinds of granular material such as a granulated catalyst which may be globular, cylindrical or rectangular in shape, for instance, to a destination such as a reactor.
PRIOR ART
A known example of such granular material feeding apparatus is a catalyst charger which is disclosed in Japanese Unexamined Patent Publication No. 59-139923. As can be seen from a plan view of FIG.
5
A and an elevational view of
FIG. 5B
, the catalyst charger comprises hoppers
50
for holding a granular catalyst, electromagnetic feeders
51
disposed close to discharge openings of the individual hoppers
50
, each electromagnetic feeder
51
including an electromagnetic feeder drive
51
a
and a trough
51
b
, funnels
52
located at downstream ends of the individual electromagnetic feeders
51
, and pipes
53
connecting the individual funnels
52
to reaction tubes.
In the aforementioned construction, the granular catalyst discharged from the hoppers
1
is caused to move on the troughs
51
b
and drop into the individual funnels
52
by vibrating the individual electromagnetic feeders
51
, in which the feeding rate of the granular catalyst can be varied by adjusting a voltage applied to each electromagnetic feeder drive
51
a
. The electromagnetic feeders
51
are supported by springs
55
on a table
54
.
This construction serves to prevent a so-called bridging which would occur when a large amount of granular catalyst is supplied at a time, and this makes it possible to uniformly charge the granular catalyst and significantly reduce the time required for charging operation.
One problem encountered with such conventional catalyst chargers is that it is difficult to precisely control the feeding rate of a granular catalyst because the feeding rate depends primarily on the frequency of vibration of each electromagnetic feeder. Another problem of the conventional catalyst chargers is that their granular catalyst transfer mechanisms are rather complicated due to the need for employing a plurality of electromagnetic feeders. A yet another problem is that powdery waste of the granular catalyst could develop during operation and accumulates on troughs, making it difficult to smoothly feed the granular catalyst and causing variations in its feeding rate.
The invention is intended to overcome the foregoing problems of the conventional catalyst chargers. Accordingly, it is a major object of the invention to provide methods of and apparatus for feeding a granular material to a destination such as a reactor in a stable manner with the capability of adjusting its feeding rate by use of a simplified transfer mechanism.
SUMMARY OF THE INVENTION
According to the present invention, a method of feeding a granular material to a specific destination includes the steps of discharging the granular material loaded in a hopper onto a trough which is disposed approximately in a horizontal position and extends from the vicinity of a discharge port of the hopper, and conveying the granular material on the trough up to the destination by vibrating the trough, wherein the granular material is delivered to the destination at a constant feeding rate by controlling the frequency of vibration of the trough while regulating the rate at which the granular material is discharged from the hopper by adjusting the opening of a gate.
In this method of feeding the granular material, it is preferable to vibrate the trough in its obliquely upward direction.
In one form of the invention, an apparatus for feeding a granular material to a specific destination includes a hopper for storing a granular material, a trough which is disposed approximately in a horizontal position and extends from the vicinity of a discharge port of the hopper, and a vibrator for causing the trough to vibrate whereby the granular material discharged from a downstream end of the trough is delivered to the destination, wherein a gate is provided at the discharge port of the hopper for regulating the rate at which the granular material is discharged from the hopper.
In another form of the invention, a granular material feeding apparatus includes a hopper for storing a granular material, a trough which is disposed approximately in a horizontal position and extends from the vicinity of a discharge port of the hopper, and a vibrator for causing the trough to vibrate whereby the granular material discharged from a downstream end of the trough is delivered to the destination, wherein the hopper is provided with partitions for dividing its internal space into a plurality of storage compartments, wherein a gate is provided at the discharge port of the hopper for regulating the rate at which the granular material is discharged from the hopper, wherein the trough has in its interior the same number of parallel passages as the storage compartments, and wherein the parallel passages have guideways formed at their respective outlets for guiding masses of the granular material into pipes which communicate with a destination.
In either of the aforementioned granular material feeding apparatus of the invention, it is preferable that a sieve be formed slightly upstream of the outlet of the parallel passage for dropping powdery waste of the granular material produced during its feeding operation. It is also preferable to construct the apparatus such that the vibrator causes the trough to vibrate in its obliquely upward direction.
A granulated catalyst formed into a globular, cylindrical or rectangular shape is one example of the granular material to be handled by the methods and apparatus of the invention.
A typical example of a destination to which the granular material is supplied according to the present invention is a reactor such as those used for producing ethylene oxide, phthalic anhydrite, acrolein, acrylic acid, and so forth, where thousands or more of reaction tubes are provided in each reactor.
According to this invention, the feeding rate of a granular material can be controlled by raise/lower operation of the gate as well as by adjusting the vibration frequency of the vibrator. As a consequence, the granular material can be delivered or charged to a destination, such as a reactor, at a constant feeding rate.
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patent: 3083811 (1963-04-01), Musschoot
patent: 4276915 (1981-07-01), Argyll
patent: 4402643 (1983-09-01), Lytton et al.
patent: 4596327 (1986-06-01), Yamano
patent: 4651868 (1987-03-01), Sticht
patent: 5485963 (1996-01-01), Walto et al.
patent: 6032828 (2000-03-01), Gicza et al.
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Kato Yasuhiro
Kawajiri Tatsuya
Nakamura Daisuke
Martin Brett C.
Nippon Shokubai Co. , Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
Walsh Donald P.
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