US1806780A - A ssigngr to egberts and schaefeb com - Google Patents

Description

M y 9 1 R. w. ARMS I 1,806,730

DUST COLLECTING SYSTEM FOR COAL CLEANERS Filed May 25, 1927 Patented May 26 1931 UNITED STATES PATENT OFFICE JRAY W. ARMS, OF CHICAGO, ILLINOIS; ASSIGNOR 'I'O ROBERTS AND SCHAEFER COM- I PANY, OF CHICAGO, ILLINOIS, -A CORPORATION OF ILLINOIS i DUST COLLECTING SYSTEM FOR COAL CLEANERS Application filed May 23, 1927. Serial No. 193,468.

I time to time throughout the specification and claims.

My invention is illustrated moreor less diagrammatically in the accompanying drawings, wherein .Figure 1 is a side elevation of an apparatus embodying my invention;

Figure 2 is an end elevation;

vLike parts are indicated by like characters throughout the specification and drawings.

VA is an air pervious. material separating deck. It is reciprocated by a pulley A driving a crank A; and a link A A is a feed shelf reciprocating with the deck adapted to receive coal or other material to be treated which is discharged thereupon through a' spout A from a hopper A. A A A are material discharge chutes which collect, and

discharge the separated material from the 5 table or deck.

B is a blower driven by a motor 13 and discharging air under pressure] through the chimney B to the underside of the pervious 13 is a dust'hoodlocated, above'the deck.

deck. B is a bellows of flexible or other suitable fabric extending down from the lower edge of the hood to the deck. This bellows extends down to the deck throughout the major portion of its periphery only so much of the space betweenthe hooda'nd the deckbeing open as is necessary to permit the atten-dantto inspect the operationof the machine. B isfla funnel formingpar't of the hood B discharging into a pipe B which pipe leads to any suitable dust collecting and separating apparatus; This funnel is located over the feed corner- 0f the table or deck, that is-,that part of the table or deck where the major portion of the dust originates. The dust separator since its'details form no part of the invention is onlyshown diagrammatically as at B Extending from the dust hood B is an air recirculation pipe C. It discharges into a dusttrap C and .a pipe C leads therefrom to the intake side of the fan B. C is a conveyor adapted to carry off the dust brought down from the air by the dust trap or settling chamber C C3 is an adjustable make up air supplyleading to theintake of the fan The necessity of this is caused by the fact that part of the air taken fromthe hood B is carried off to the dust separator and part of .it

I comes backto the fan or blower. Some of the 7 make up a1r comes in between the hood l3 and the deck and the adjustable make up' opening will be so set and controlled either manually or automatically that. there will always be an inflow of air between the hood.

"and the deck and never an outflow. The re sult of this is that no dust laden air gets out into the room or house in which the table is operating. The tendency of air flow is al- Ways inward in the entire system except that partof. it leading from the blower to the underside deck which is above atmospheric pressure. Thus there is no tendency for dust to escape anywhere fromthe system into the room.

Except in connection with the Very finest screens the presence of dust in the recirculated air and therefore in the air blown up through the screen or pervious deck to float and assist in separating the material, is not a detriment but an advantage because it is understood that in connection with dust separating the flowing stream of finely divide-d material travels along a separating table under the influence of gravity, the reciprocation of the table and the floating effect of the air. Experience shows that if anything can bedone to increase the specific gravity of the air orgas stream the material can be floated "with a decreased velocity, pressureand volume of air. The presence of dust then in the it does the specific gravity of the air, helps rather than hinders in the separating operation.

Experience shows that there is a satura tion point at which the air stream will carry no further dust. Beyond that point dust may be deposited out in the dust trap or may be screened out by the bed of traveling material to be treated.

Only that relatively small proportion of the air having the maximum amount of dust is drawn out through the funnel and discharged to a separate dustcollector. Thus a relatively small dust collector can be used and a high degree of elliciency in dust collection can be obtained. It will not be suiiicient, of course, to try to recirculate all the air because under these conditions pressure variations would set up and it would be quite impossible to keep a suction on the system and on the space between the hood and the deck and under such conditions air and dust would escape in undesirable quantities into the room and al o heavy particles which are frequently entrained by the air to the dust separator might if they were allowed to work back th 'ough the screening system clog the system.

Vhile I have shown part of the air taken from the hood and discharged through a dust separator, it is obydous that suchair may be discharged into any suitable system and the dust separator needs not to be of any particular type and might take any number of different forms and in fact it is conceivable that many things might be done to the air before it reaches the dust separator or it might merely be discharged away from the system. 7

One of the important reasons for taking some of the air from the hood. and discharging it either to a separator or hood is that by doing this it becomes possible to keep all the air except that portion below the deck under sub-atmospheric pressure so that all leaks except in that relatively small part of the system which is under a pressure above atmospheric will be in, instead of out, and there will be no tendency for dust laden air to escape from the system into the room or house where the system is located.

I claim:

1. In an air cleaning system, a pneumatic stratifying table, a blower adapted to discharge air under pressure therethrough, a hood overlying the entire working area of the table, means for withdrawing air from the hood, and discharging it to the intake side of the blower for recirculation through the system, meansfor withdrawing from the system some of the air from the hood, the system being closed except between the hood and the table whereby air to replace that withdrawn from the system must enter the system inwardly across the sides of the table.

2. In an air cleaning system, a pneumatic stratifying table, a blower adapted to discharge air under pressure therethrough, a dust separator and means for conducting to the separator and withdrawing from the system that portion of the spent air containing the largest proportion of dust and means for conducting the remainder of the spent air back to the intake side of the blower for recirculation through the system.

3. In an air cleaning system, a pneumatic stratifying table, a blower adapted to discharge air under pressure therethrough, a dust separator and means for conducting to the separator and withdrawing from the system that portion of the spent air containing the largest proportion of dust and means for conducting the remainder of the spent air back to the intake side of the blower for recirculation through the system, and means for discharging into the system across the sides of the table a current of make-up air.

4. In an air cleaning system, a pneumatic stratifying table, a blower adapted to discharge air under pressure therethrough, a dust separator and means for conducting to the separator and withdrawing from the system that portion of the spent air containing the largest proportion of dust and means for conducting the remainder of the spent air back to the intake side of the blower for recirculation through the system, and means for discharging into the system across the sides of the table a current of make-up air, and controllable means associated with the blower for adding additionalmake-upair thereto.

'5. In an air cleaning system, a pneumatic stratifying table, a blower adapted to discharge air under pressure therethrough, a dust separator and means for conducting to the separator and withdrawing from the system that port-ion of the spent air containing the largest proportion of dust and means for conducting the remainder of the spent air back to the intake side of the blower for recirculation through the system, and a dust trap through which the air passeson its return to the blower.

6. In an air cleaning system, a pneumatic stratifying table, a blower adapted to discharge air under pressure therethrough, a dust separator and means for conducting to the separator and withdrawing from the system that portion of the spent air containing the largest proportion of dust and means for conductingthe remainder of the spent air back to the intake side of the blower for recirculation through the system, and means for discharging into the system across the sides of the table a current of make up air, and a dust trap through which the air passes on its return to the blower.

7. In an air cleaningsystem, a pneumatic stratifying table, a blower adapted'to discharge air under pressure therethrough, a

dust separator and means for conducting'to Signed at Chicago, county of Cook and State of Illinois, this 20th day of May, 1927.

RAY W. ARMS.

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