US2733398A

US2733398A - Bruckner

Info

Publication number: US2733398A
Authority: US
Publication date: 1956-01-31
Anticipated expiration: 1973-01-31

Description

Jan. 31, 1956 w. BRUCKNER MOTOR CONTROL FOR ACTUATING A DUST COLLECTOR 2 Sheets-Sheet 1 Original Filed Oct. 12, 1950 cnecorr FIG. 12

INVENTOR g g/A4 use Dwc/rA/EE W42: flwx fi HT7OBNYJ Jan. 31, 1956 w. BRUCKNER MOTOR CONTROL FOR ACTUATING A DUST COLLECTOR 2 Sheets-Sheet 2 Original Filed Oct. 12, 1950 TIMER OPERATINQ Cnewn' FIG. 4

HOLDING Cnecmr INVENTOR. WAL ree Ema v 3 x 9 Tram/E) r Mfi'lllil QONTROL FUR ACTUATING A DUST CSLLECTOR application October 12, .d and this application 276,225

1950, Serial No. 189,755. February 4, 1952, erial 1 Claim. (Cl. 318-470) This application is a division of my co-pending applica tion Serial No. 189,755, filed on October 12, 1950, for

the invention relates to a system of the type having a number of compartments each containing fabric bags with means for directing dust-laden air into the bags and for drawing the air out of the compartment from the exterior of the bags, with the result that the dust is deposited on the interior of the bags. In such systems it is necessary to shake the bags from time to time to clear the dust clinging to the interior and deposit the same in a suitable receptacle for ultimate discharge.

The invention is concerned with automatically actuated means for shaking the bags of the different compartments as such operation may be required. I determine the time of initiating the shaking operation by the relation of the air pressure within the bag to that outside of the bag. As the dust builds up in the bag the diiferential between internal and external pressure increases, and in my invention I avail myself of this increase of differential pressure to actuate mechanism to set in operation power means which shakes the bags. The same actuation also operates valve mechanism to reverse the direction of flow of the air, so that it may now pass from the exterior of the bags into the interior and assist in loosening the dust in the bags.

My invention includes such a method of controlling the shaking of the bags in any compartment, and, as it is desirable that the shaking occur in only one compartment at a time, my invention includes also provision for preventing at that time the operation of the shaking means for the other compartments The invention also includes suitable apparatus for use in carrying out the above-outlined method. The drawings disclose two forms of such apparatus, each of which is included within my invention and which will be hereinafter described in detail.

in the drawings, Fig. l is a vertical section of a controlling device operated by the ditferential pressure at the bags; Fig. 2 is a sectional plan of such controlling device, the plane of the section being indicated by the line Z-2 on Fig. 1; Fig. 3 is a diagram illustrating by heavy lines, the particular circuit brought into action by the existence of a predetermined pressure differential in one unit which will result a few seconds later in the shaking of that unit; Fig. 4 is a diagram similar to Fig. 3, the position of the parts being the same as that of Fig. 3, but illustrating in heavy lines the circuit for holding the controlling circuit in its position; Fig. 5 is a diagram illustrating the shaking circuit as established by the timer a few seconds after the establishment by the relay circuits of the timing circuit of Fig. 3.

The general dust collecting and shaking system is shown and described in greater detail in the above-noted parent application and this description will be hereinafter limited to the arrangement including a pressure responsive device for removing accumulated dust from the bags.

automatically nited States Patent Heretofore it has been customary to operate manually the valves which control the shaking mechanisms and the reversals of the air. However, with such cleaning system, or any system, controlled according to my invention, the

valves WhlCh control the shaking mechanisms are operpressure within the bags and that on the exterior thereof.

In the embodiment shown particularly in Figs. 1 to 5 there is one pressure-operated control unit for each compartment. It comprises an air-tight casing 40 containing an extensible bellows 41, a micro-switch 42 operated by the bellows and a pair or

relays

43 and 44, the first relay 43 being controlled by the micro-switch and the second relay 44 controlled by the first. Two air conduits 46 and 4-7 are provided, the first of which (46) leads to the interior of the bellows and the second (47) to the space in the casing 45) outside of the bellows. One of these conduits is connected with the space within the bags and the other with an air space outside of the bags.

The normally expanded bellows holds the switch operating lever 45 in idle position to leave the microswitch contacts open. As the external pressure on the bellows increases the top of the bellows gradually sinks, so that the lever 45 which operates the micro-switch and bears against the top of the bellows is pushed down by the internal spring pressure in the micro-switch. This does not immediately close the switch but does close it as soon as the bellows has descended farther to allow the spring to push the lever still farther down.

The micro-switch 42 within the pressure unit suitable construction. it is shown as carried parallel arms of a standard 56 and pivoted thereto at 51, Figs. 1 and 2. As stated, it has an operating member 45 hearing against the upper end of the bellows and spring pressed downwardly. When the bellows contracts due to the pressure within the bags (conveniently called the hopper pressure) exceeding the pressure on the bags exterior (called the compartiiwnt pressure) such movement lowers the upper end of the bellows and thereby operates to close the circuit within the micro-switch.

Rigidly connected to the micro-switch body is an arm 55 pivoted at 51 and shiftable up-and-down at its free end 55, and locked in set position by a clamping screw 57. The raising of this arm carries the operating member 45 farther from the bellows so that a less contraction of the bellows will operate the switch; while a lowering of the arm end 56 will require a greater contraction. Thus I am able to vary the effective operating differential pressure as desired.

While I have shown the conduit 26 from within the bellows connected to the compartment space and the conduit 47 connected to the hopper space these connections might, if desired, be reversed. Then an increase in the is of any within the diiferential pressure would cause an expansion of the bellows. In that case the lever 45 would have to move upwardly to close the micro-switch, and the control arm would be swung downwardly to reduce the amount of difierential pressure requ red to operate the lever In the embodiment of l to: 5, one of the contacts of the micro-switch is permanently connected to a power line while from. the other contact a conductor e'z'i leads to the relay Each relay 43 and id has an armature with two switches operated as a unit. Suitable springs tend to maintain the switches in one extreme position while the energization of the relay magnets will bring them into the other position.

The circuit lines from the relay i4 and from the two double arm switches are preferably all grouped into a single cable and pass outwardly from the casing 46 to the exterior as indicated at $9, Figs. 1 and 2. This same cable may contain the conductor leading permanently to the first terminal of the micro-switch. This consolidation of all the conductors leading from the box 40 simplifies the maintenance of the casing 40 in an air-tight condition, by the use of proper packing about the cable where it passes through the wall of the casing.

It will be seen that whether I employ a selective system for controlling the shaking in each compartment according to the conditions therein, or a successive system to operate the whole set one after another according to the general pressure conditions, I employ in either case the differential pressure control actuated by the difierence in pressure between the interior and the exterior of the bags.

When the pressure differential in any compartment reaches a predetermined amount, the resulting contraction of the bellows in the corresponding control unit operates the associated micro-switch and thereby this through the conductor 43, Fig. 5, closes the circuit through the relay 43, and thereby initiates the electric operation which results eventually in the energization of the shaking mecha nism.

We will now refer to Fig. 3 which shows by heavy lines the circuits which become operative upon the energization of the relay 43. This relay operates two switches 66 and 67 to swing them from the normal idle position to the position of Fig. 3. Current now flows as follows:

Tracing the circuit via the heavy lines in Fig. 3, this circuit passes from the alternating current power line instantaneously designated plus via the line 70, thence to the line 71 to the micro-switch. The micro-switch being closed, the current passes by the connection through the relay 43 to the line 49, thence via the switch 6% to the line '72, to the line 75, passing out at the power line instantaneously designated minus. This results in the energization of the relay 43 which brings its two switches 66 and 67 into the position shown in Pig. 3. This causes the circuit through the line 48 to divide with part passing via the line 7 6 and the switch 67 to the line 81 to the line 30 and thence through the synchronous motor of the timer and thence to the minus terminal.

When the synchronous motor 62 begins to operate it rotates the two

cams

63 and 64 which will first close the switch 65. This operation brings into action the holding circuit illustrated in Fig. 4 to maintain the motor 62 energized irrespective of the condition of the pressure operated micro-switch. This is an important feature because when the shaking operation and air reversal, which the differential pressure controller initiated, start operation pressure conditions immediately change in that compartment and the bellows would soon return to idle position, opening the micro switch, and such opening would stop the operation. This is prevented by the holding circuit.

Tracing the holding circuit, as indicated in Fig. 4, it passes from the line instantaneously designated plus via the switch 65 to the line 530, thence to the line 81, through the closed relay switch 67, through the relay 43 to line 49, through the switch 6%; to the line 72, to the line 75, and back to the power source. It is seen that the operation is initiated by the difference in pressure on the inside and the outside of the bags which in turn causes the shaking of the bags and air reversal of one compartment at a time.

it results from the above described holding circuit that the micro switch is rendered idle and its condition is immaterial, but the timing motor continues to rotate its cams 63 and The condition at this time of the timer cams renders the electrical system ready for the application of paralyzing circuits which prevent shaking and air reversal in any compartment except the one being shaken, and the paralyzing circuits are provided to prevent the pressure control of any other compartment from acting while one compartment is acting. These circuits and their operation are described in greater detail in my parent application as cutting out all of the pressure controlled switches 42 so that, for example, the condition in compartment No. 1 cannot be effected by changing pressures in it or in any of the other compartments.

This situation brings into action the shaking of the circuit for compartment No. 1, shown in Fig. 5. Trac ing the circuits in Fig. 5 the circuit from the line instantaneously designated plus divides as before, one part continuing through the motor 62 and the other part passing via the line 70 to the line 71 to the line 95, thence through the solenoid 96 operating the valve 32, thence via the line 97 through the switch 69 of the relay 44 to the line 98, to the line 8'5, through the switch 66 now closed by the cam 64 and back to the power source.

The circuit just described causes the shaking operation in compartment No. 1 and the reversal of the air current therein so long as the switch so continues closed. That is to say, air is admitted to the shaking cylinder 31) and also the cylinder 25 operating the air reversing valves 22, 24, with the result that the bags are shaken and the direction of the air current reversed in the compartment which has caused the actuation of the differential pressure controlling device.

When the synchronous motor 62 has rotated for a few seconds the cam 64 will have opened the switch 66, stop ping the shaking operation. The cam 63 then opens the switch and stops the motor and the normal or idle condition of all the compartments is restored.

I claim:

in a dust collecting apparatus having a confined air flow path adapted to develop a differential air pressure between its ends corresponding to a predetermined accumulation of collected dust therein, a pressure responsive device for removing the accumulated dust comprising in combination, a closed casing, a bellows within the easing having one end free and the other end fixed, conduit means for independently coupling one end of the air path to the interior of the bellows and the other end of the air path to the interior of the casing and exterior of the bellows, an electro-magnetic dust removal mechanism adapted to be selectively energized for a predetermined interval of time sufiicient to remove accumulated dust from the confined air path, an energizing circuit for said mechanism including a switch, a motor-driven timer cam adapted to selectively engage and hold said switch in position to activate the electromagnetic energizing circuit for the predetermined time interval, an energizing circuit for the motor-driven timer cam, a second switch for activating the timer cam energizing circuit, means responsive to operation of the timer cam for independently maintaining the timer cam energizing circuit active during said predetermined time interval, said second switch operatively disposed in the casing and having an operating member engaging the free end of the bellows for operative position ing thereby in response to a predetermined differential in air pressure on opposite sides of the bellows.

References Cited in the file of this patent UNITED STATES PATENTS 1,444,403 Varley Feb. 6, 1923 1,750,336 Terry Mar. 11, 1930 2,176,817 Jacobson et al Oct. 17, 1939 2,304,802 Crew Dec. 15, 1942 2,432,312 Hasselhorn Dec. 9, 1947 2,454,423 Baak Nov. 23, 1948 2,493,190 Fuchs Ian. 3, 1950