US1764861A - Apparatus for separating dust or fume from air - Google Patents

Description

June 17, 1930.

Filed Nov. 15, 1926 Patented June 17,1930

- UNITED sTATEsPATENT orncs J'OHAHNEB PIETEB VAI' GELDEB, OI GRANVILLE, NEW SOUTH WALE B, AUSTRALIA APPARATUS FOR BEPABATING DUST OBJ'UME FROM Application fled'liovember 15, 1888, Serial No. 148,568, and in Australia June 88, 1828. v

Itis common practice to eflect the removal of accumulated dust or fume from fabric tube filters by mechanically shaking or rapping the suspension frames by which they are sup orted, and in certain cases pro- VlSlOIl is ma e for stopping the air-flow during the shaking or rapping operation in order to allow settling of the dust which is thereby liberated in the casings. The tubes are subjected to considerable mechanical stress, par ticularly near their top ends, when they are thus forcibly shaken or vibrated, and their useful life is consequently abridged, and delays and inconveniences result from the closing'down of sections of the apparatus to effect replacements.

The present invention consists in means whereby the tubes are discharged of accumulated dust by collapsing them automaticalgo ly at intervals without shocking them or vibratin them. By these meansthelife of the tu as is conserved and stoppages to effect replacements become necessary only when the tubes have been used out, and have as become too frail to maintain their integrity in service.

The collapsing of the tubes to liberate accumulated dust is efiected by closin the suction orifice of the casin chamber %or a few moments at intervals 0 anything from say one minute to thirty minutes and simultaneously opening and closing another orifice in it to atmosphere several times at short intervals. These actions are performed at pre- 88 arranged times by constantly runnin mechanism. The tube clearing is there ore effected automatically, and when (as would almost invariably be the case in practice) two or more tube chambers are operated in 4 parallel without interrupting the continuity of the dust collectin operation. Dislodgement of the accumu ation of dust han to the tube walls is effected in the relatively gentle shaking which is caused-in the suc- 5 cessive equalization and breaking of themetime, is increased very substantially, so that the cubic dimensions of the casings, and the number or size of the fabric tubes may be correspondingly reduced for a given de: mand.

In the accompanying draw Fig. 1 is a frontal elevation 0% portion of an apparatus for'extracting dust-from air;

Fig. 2 is a broken transverse sectional elevation through the machine; and

Fig. 3 is an enlarged fragmentary view of the valve operating mechanism.

The machine is constituted of a-pluralit of casings 10 usually constructed of woo and all built on a tunnel box 11 and all connected to a suction pipe through which air is educted. One or more entr vents 12 are provided in the upper part 0 the tunnel box 11, and a worm conveyor 13 is fitted inthe bottom portion of it to move the dust which is deposited in it towards one end of it where provlsion is made for a cleaning door through which the accumulated dust may be removed. The inlets 12 are piped up to a artments or machines having a dust atmosp ere with the object of drawing the dusty air through the machine and extracting the dust from it.

The floor 15 of the chambers 10 which separates these chambers from the tunnel box 11 below them is apertured and the apertures The upper part of each chamber 10 is fitted with two neck pieces 18 and 19. One vof these neck pieces 19 is connected up to a main suction pi e (not shown). A condition ofsubatmos 8110- pressure is maintained in that pipe ymeans of an exhaust fan. In the neck plece 19 a butterfly valve 20 is fitted, carried on a spindle 21, and the spindle 21 is armed with a crank lever 22 by which the valve may be moved to open and close it.

The operating movements are effected by a link 23, one end of which is ivotall connected to the lever 22; the ot er en of it slides in a bearing 24. The link 23 is moved by means of an arm 25 to which reci rocating motion is applied by the means e'reinafter described. The top end of this arm is slotted, and a cross head 26 pinned on the link 23 carries an offset pin which engages the slotted end of the arm 25. Consequently, when the arm 25 is reciprocated, the link 23 is reciprocated, and the valve 20 is o ened or closed accordingly. 27 is a helica spring sleeved over the link 23 betweenthe cross head 26 and the stop 24.

The other neck piece 18 is also fitted with a butterfly valve 28 on a spindle 29, and this s indle is fitted with a crank arm 30 to which t e top end of a link 31 is pivotally connected. The bottom end of this link is attachedto a tappet 32 and the tappet is rotatably fixed on a slide bar 33. At one end of it th1s slide bar works freely through a fixed slide bearing 34. The other end of it is pivotally connected at 35 to the bottom end of a lever 36 which works on a fixed fulcrum 37. An adjustable screw 38 is carried in a lug on the lever 36 in the path of movement of the arm 25. When the arm 25 is moved to its extreme position it engages the screw end 38 and moves the lever 36, thereby moving the slide member 33 and bringing the tappet 32 into operative relation to the striker finger 39 on the shaft 40. I

The rod 31 is thus reciprocated and the valve 28 is opened and closed re eatedly beigre the valve 20 is again opened by the cam The bottom end of the arm 25 is carried on a fixed fulcrum pivot 41, and above the pivot it is fitted with an offset roller pin 42 which works in a groove cam 43 which is cut in the side of a worm wheel 45. The worm wheel- 45 meshes with a worm 46 which is keyed on the shaft 40; the shaft 40 extends the full length of the assembly of casings 10 and is driven at one end of it through gearing 47 from a belt pulley 48. The dr1ve to the conveyor 13 is conveniently taken from the jackshaft which carries the-pulley 48, by means of the belt or chain 49. The outer end of the neck 18 opens to atmosphere.

It is important to note that the fabric tubes 16 are held fixed at their ends and that their supports are not subjected to rapping or other vibration. Consequently there is no mechanical force applied to the tubes 16 which would operate to do them mechanical injury, as happens in dust extractor a paratus which includes shakers or stri ers which are arranged to apply bodily movement or vibratory movement to the fabric tubes.

In operation, the valve 20 is normally open and the valve 28 closed and the shaft 40 is in continuous rotation. Once in each rotation of the wheel 45, the arm 25 is reciprocated by the groove cam 43 and the roller pin 42 on the arm 25, this movement being a gradual one. It' is communicated through the link 23 and crank 22 to the valve 20 and that valve is brought slow] to the closed position. When the valve is t us closed, the casin 10 is no longer subjected to vacuum throng the suction pipe line. As the tunnel 11 underlies two or more of the casings 10, each of which is separately fitted with valve mechanism as shown in Fig. 1, a condition of partial vacuum is maintained in the tunnel box 11 through one or more of the casin s which for the time bein are connected to t e exhaust, notwithstan ing that the exhaust valve 20 on one of the casin s 10 is closed. The gearing is set so that tie exhaust valves 20 on the several casings 10 which are associated with the one tunnel box 11 are not opened simultaneosly. Consequent upon the condition of partial vacuum existing in the tunnel box 11 and the breaking of the vacuum in the easing surrounding the tubes 16 on one of the casings by the closing of the exhaust valve 20 of that casing the tubes 16 in that casing slowly collapse and in this collapsing movement they suffer a very gentle agitation throughout their entire length; this agitation is not sufiicient to dislod c all the accumulated dust within the tu es. During the time that the exhaust valve 20 is closed, that is for the short period whilst the cam 43 holds the offset pin 42 in the out position and so forces the arm 25 over, the lever 36 is moved through the contact of the arm 25 with the screw 38 and is held over so that it pushes the slider 33 and brings the tappet 32 into operative relation to the striker 39 on the shaft 40. In the rotation of the shaft 40 the Ill tappet 32 is struck once in each rotation, and

tion is re-established in the casing 10 surrounding the tubes 16. As the pressure becomes equalized within the tubes and outside of them owing to the porosity of the tubes, the tubes are unconstrained and fall back into their normal tubular shape. The result is that whilst suction is cut off by the valve the tubes 16 are several times gently flapped by collapsing them by means only of variation in atmospheric pressure and allowing them to distend again; these repeatedmovements of the tubes result in dislodgment of nearly the whole of the accumulated dust, which when liberated falls down through them into the tunnel box 11.

lhe clearing of the accumulated dust is effected periodically and automatically and in a manner which ensures maximum life to the tubes, inasmuch as they are not subjected to destructive mechanical stresses or rough treatment during the clearing operations.

What I claim as my invention and desire to secure by'Letters'Patent is 1. In filter apparatus for extracting dust or fume from air, enclosed filter tubes, means for interrupting the air suction periodically and for repeatedly closing and breaking the atmospheric depression in the space surrounding the filter tubes while the suction is interrupted, said means comprising a valve for controlling the air suction connection, a valve for controlling a vent to atmosphere, a shaft, a striker on said shaft, a cam, a slow gear between said shaft and said cam, an arm link-connected to the valve in the outgoing air suction pipe and adapted to be reciprocated b atmospheric valve and adapted to be reciprocated by said striker to operate said atmospheric valve, and means operable by said arm for moving said tappet into register with said striker to repeatedly operate said atmospheric valve while the valve-in the air suction pipe is held closed, and for moving said tappet out of register with said striker when the valve in the air suction pipe is held open.

2. In a tubular filter for extracting dust from air, a casing, fabric tubes arranged in spaced relation within the casing, the casing having a dusty air inlet below the tubes, a filtered air suction connection from the space in said casing which surrounds the tubes, a valve for controllin the air suction connection, means for closin said valve periodically, a vent to atmosp ere from said casing space, a valve controlling said atmosphere vent, means for repeatedly opening and closing said vent valve at short intervals while the suction valve remains closed including a shaft, a striker on said shaft, a cam, a slow gear between said-shaft and said cam, an arm connected to the valve controlling the N suction connection and reciprocated by it cam to operate said valve, 3 tappet consaid cam to operate said valve, a tapl pet lin r-connected to the

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