CA1064835A - Flushing air valve - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A flushing air valve for selectively subjecting a selected filter member or members to a flushing air impact to remove a dust deposit on the member. The valve member of the type of an axially movable plate closes a conduit between a flushing air chamber and a clean air plenum ad-jacent the respective filter disposed in a cleaning compart-ment of a dust removing filter apparatus. The opening and closing of the valve is governed by opening or closing of a pilot exhaust valve. As the pilot valve opens, the flush-ing air pressure acting on the side of the valve member fac-ing the exhaust is reduced so that the flushing air pressure acting on the opposite face of the valve member opens the valve. Means providing an air cushion for decelerating the opening stroke of the valve member is provided to prevent the valve member from striking against the chamber wall, to thus reduce the noise of operation of the valve. The required pres-sure of the flushing air is reduced as the operation is govern-ed solely by opening or closing the pilot valve, without any further requirements for the operation of the pilot valve, such as re-directing the flow of the flushing air etc.

Description

ti4~35 The invention relates to a flushing air valve for cleaning of at least one hollow filter member, said valve having a flat valve member whose one side Eorms with its inner portion the closure of the inlet of a flush:ing air conduit, peripheral portions of said one side being located adjacent a flushing air chamber, wherein khe valve member is arranged for movement in a holding chamber in a direction pexpendicular to said one side, under the influence of the flushing air, and wherein the holding chamber is arranged in a continous communication - on the one hand - with flushing air chamber, through at least one restric-tor means and - on the other hand - with a control air conduit adapted to be closed by a control valve. The term "holding chamber" implies that the main function of such chamber is to maintian the flat valve member in closed position during normal operation of the device.
In one flushing air valve of this type known for years the valve member is made from a rubber diaphragm which is clamped about its entire periphery between the housing of the holding chamber and ~
that of the flushing air chamber. The valve can be used in flush- ;
ing one or more filter members, ~.g. filter hoses or filter bags. ~-Air filters with this flushing system have enjoyed an exceptionally wide use as-they are capable of operating with a small pressure of the flushing air due to the overall structure of the device. An overpressure of the maximum of 0~5 atu (a~mospheric excess pressure ;
in kg/cm2) is sufficient for flushing ~ dividual hoses. Thus, simple air compressors can be used.
An increasingly undesired drawback is in the limitation of the field of application as the maximum temperature of QperatiOn is about 150C due to the use of the rubber diaphragm.
In another known embodiment, the diaphragm is not stretched but is arranged for free movement, On shutting off the flushing air opening, it sets free the filling of the flushing air chamber over the control valve. Therefore, the ~; .
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, , c~ntrol ~alve must be of a structure suitable for reversln~
the flow directlon, not merely for shutting off the exhaust air. Its structure is expensive and its speed o~ response is too small. As the holding chamber is not in a constant commun-ication with the ~lushing air chamber, the flushing cannot be interrupted at a given time by simply closing the control valve; insteadl pressurized air must be supplied via the control valve into theholding chamber in order to enable the re-closlng of the ~lushing alr openlng. In this case, too, the response speed is smaller so that the duration of the flushing pulse is difficult to control. In order to secure sufficient flushing, the duration o~ the flushing pulse must be selected to be greater than in the first mentioned embodiment, so that a considerable additional consumption of ~lushing air is necessaryL In this case the operational temperature is also llmited.
It is known ~rom the art of digital, pneumatic and hydraulic control means to employ valves whose valve members are of the type of a solid plate. They su~er from the same drawback as the structure described above, namely that they require a positive control pressure for closing the valve and oannot be controlled by simply shutting o~f the exhaust air.
Their use is primarily considered ~or h~draulic devices.
They are primarily intended to improve the sealing erfect and to reduce the oil leakage. Their transforming to the sizes and speed of pne~atic flushing air valves for air and gas filters is impossible due to the intolerable noise on the impact of the plate against the housing of the bu~er chamber.
The ~lushlng air valve according to the inventlon ls characterized in that the valve member is a plate which has a small clearanoe with respect to the walls o~ the ~olding chamber, the plate bein~ guided by a guide provided on the housin~ of the holdingchamberD the plate being provided .. . . .. .

6~35 ~t lts race ~dj~cent to the use~l air condu~t with at least one cyllnder arranged to enter into a hollow of the houslng.
It is then posslble to produce by simple means a temperature independent flushing nir valve which ls decele-rated at the end o~ its opening stroke wlthout the need for a separate part. Nevertheless, the l~ftins o~ the valve member is e~fected much ~aster th~n in the kno~rn diaphragm valve so that the pressure of the flushing air can be selected to be even smallerq Even ~hen flushing a plurality of hoses, the required pressure of the flushlng air is much smaller than in the known structures~ In a particularly advanta~eous embodi~
ment, a portion o~ the control air conduit adjacent the holding chamber is used as the recess to form with the cylindric member cutout means ~or cutting o~f the exhaust air flow.
In this case, the deceleration by cuttlng off the spent air conduit is effeoted b~ the valve member itsel~, while the air ramaining in the holdingchamber acts as a cushioning.
In further advanc1ng this conceptt the cylindric member can be permanently received in the exhaust air condult to thus form in cooperation with same a ~uide for the plate. It ~om-prises a conn~c~ion conduit arranged to commun1cate at its one end with the control air conduit and with the other, through a communication passage in the cylindrical member nea~ the plate, with the holdingchamber. It is possible to arbitrarily select the wldth o~ the communication passage along its axial length depending on the desired course of deceleratlon.
Furthermore, the housing of theholding chamber may be deslgned to comprise a cylindric s~de wall and a cover flxed-ly secured to same, with the cover comprisin~ the reoess ~or recelving the cyl~ndric member9 wherein the cover serves the purpose of a ~ixture on one wall of the flushing air chamber and the cyl~ndric wall extends lnto ~he flushlng alr chamber.

The valve can thus be mounted on the flushing air chamber as 4 _ - "
~06~183S

a unit. The overR11 height ls mlnlmum a~ th~holdingchamber ls lo¢~ted inslde the ~lushing air ohamber.
In general tPrms, the present invention provides a flushing air valve for use in a filtering apparatus comprising a plurality of hollow filter members, said flushing air valve : being of the type arranged in a housing for flushing at least one of said filter members, said flushing air valve including a flat valve member whose one face is arranged to close by its inner portion a flushing air conduit, the outside portion of said one face of the valve member being arranged to face the interior of a flushing air chamber of said apparatus, said ~:
valve member being movable in a holding chamber in a direction generally perpendicular to the said one face under the action of flushing air pressure, said holding chamber being arranged in a permanent communication with the flushing air chamber through at least one restrictor means, said holding chamber further communicating with one end of control air exhaust means arranged to be selectively opened or closed by a control valve; said valve member being a plate whose peripheral edge is closely spaced

2~ with respect to a wall of said holding chamber; said valve ~;~
member being provided with guide means secured to said housing for guiding the movement of said plate in said direction;
the surface of said valve member facing said exhaust means forming, together with a portion of said valve housing facing said surface of the valve member, a piston-cylinder arrangement whose piston is adapted to be slidably received in the cylinder of said arrangement. :
The present invention further provides a flushing air valve for use in a filtering apparatus comprising a plurality of hollow filter members, said flushing air valve being of the type arranged in a housing for flushing at least one of said filter members, said flushing air valve including a flat valve member whose one face is arranged to close by its inner portion ~; a flushing air conduit, the outside portion of said one face of ~k ~`, .

~a~4~3s the valve member being arranged to face the interior of a flushing air chamber of said apparatus, ~.aid valve me~er being movable in a holding chamber in ~ direction generally perpen-dicular to the said one face under the action of flushing air pressure, said holding chamber being arranged in a permanent communication with the flushing air chamber through at least one restrictor means, said holding chamber further communicating with one end of a control air exhaust means arranged to be selectively opened or closed by a control v~lve; said valve member being a plate whose peripheral edge is closely spaced with respect to a wall of said holding chamber, said valve member being provided with guide means secured to said housing for guiding the movement of said plate in said direction; the ~ace of said valve member facing said exhaust means being provided with a cylindric member arranged to be received in a recess provided in the valve housing.
The drawing shows, as an e~ample, four embod~ment~ o~
the ln~entlon.
Figure 1 ls a sectional vlew o~ a hose ~ er provided with a ~ir~t embod~ment Or the flushing air valve according to the lnventlon.
Flgure 2 ~hows, on an enlarged scale, a sectional ~iew ~;
: o~ one ~lushing air ~alve of Figure 1.
~igure 3 shows the same embodiment o~ the flushing alr valve ln sectlonal view correspond~ng to that o~ ~igure 2 Figure 4 shows the third embodlment o~ the ~lushlng air valve in a ectional vlew corresponaing to that o~ Figure 2.
Flgure 5 shows a sectional vle~ o~ a hose ~ er provided ~lth ~lushing air valves o~ the ~ourth embodiment.
Figure 6 shows, on an enlarged scale, a ~ectlonal view of ~lushing a~r v~lve o~ Flgure 5.

S~

1064~35 The houslng 11 of the hose .~ er according to Fl~ures 1 and 2 is dlvlded by partition ~a:lls 12, 13 lnto a cleaning compartment 14, a clean alr plenum 15 and 9nto a ~lushlng air chamber 16. In the cleanin6 compartment 14 are arran~ed filter hoses 1~ closed at thelr bottom en~s 20. They are ~l~ed, by clamps 21, to sleeves 22 arranged on the intermedlate partitlon 12, to ~orm a passage 23 between the inside o~ the filter hoses 19 and the clean alr plenum 15. An inlet tube 25 cvmmun-lcates into the cleanlnE compartmen~ 14. It ls provided with a discharge olo~ure 26 having a se~m~nt wheel 27, A dlscharge tube 29 ls ~rrang~d at the outlet o~ the clean air plenum 15, Into the flushing air chamber 16 communicates ~ pressurlzed : alr conduit 31. On the top wall 32 of the ~lu~hing a~r chamber 16 are secured by ~eeu~ing meanæ ~ot shown) flushin~ air val~es 34. To each ~ilter hose 19 is associated one flu~hing ~;
air valve 34. Communicating outwardly rrom the ~lushlng ~ir :

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~ 3 5 valve 34 ls a ~lushin~ air duct 35 rixedly secured to the ~artition 13 reRchin~ lnto the th~ clean ~ir plenum 1~. It communicates with same at a spacing ~rom and in the directlon of the correspondin~ passage 23. l'he houslng 33 forms the holdin~chRmber 37 for the valve member of the type o~ a plate 38. The bottom side 40 of plate 38 rorms with lts inner portion 42 a cloæure o~ an inlet 43 of the flushing air conduit 35. The bottom side 40 ls adjacent to th~ flushing ai~ chamber 16 ~ith its perlpheral zones 45.
The plate 38 is arranged for mo~ement ~n the holding chamber 37 in a directlon perpendicular to lts bottom slde 40. It has a small spacing 41 relative to the housln~ 33~
the spaeing thus forming a restrictor means of the type of a permanent communication between the ~lushing air chamber 16 ana the bu~rer chamber 37.
Theholding chamber 37 communicates with a co~trol air ~onduit 48, which has a oylindric~l recess 49 o~ the b~using 33. The control air conduit 48 is arranged to be closed by a control valve 51. It communi~ates wlth a chamber 53 of the control valve 51 whlch includes a ~alve member 54 shown in a dlagrammatic way. The valve member ls pressed by a spring 55 in the direction of lnlet 56 of an exhaust oonduit 57 whlch communic~tes wlth the atmosphere. An electrlc windln~
59 actuated by eleotrlcal current controllea by a ~ontrol de~ice (not shown), is used ln pullin~ back the v~lve member 54 to thus open the inlet 56 ~or communlcatlng the aontrol air conduit 4B with the exhaust conduit 57.
The plate 38 carrles on its upper side 61 a cylindric .
member 62 which is permanently received ln the cylindrical recess 49 to thus form the guide means ~or the plate 38. It ~ncludes a communlcation conduit 64 termlnating at one end with the recess 49 and with the other end through a communlcation openlng 6~ disposed on the cylindrlc body 62 in pro2imity to plate 38~ ~ith the holding~hamber 37.

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The operation ls as followss The contamlnated air is fed, by a blowing device (not shown) lnto the cleanlng chamber 14, via the inlet tube 25, either by compression or by suction. The air penetrates into the inside of the filter hoses 19 while a portion of the dust remains deposited on the outslde surface of the filter hoses 19, the maJor portion of the dust ~alling downwards and being removed by the permanently dr~ven discharge segment wheel 27 from the cleaning compartment 14~ The segment wheel 27 also serves the purpose of sealing the outlet o~ the compartment.
Clean air flows from the inside of the filter hoses 19 ; through the passages 23 into the clean air plenum 15 and leaves same through the clean air outlet tube 29.
Eventually, the layer o~ dust on the outside surface of the fllter hoses 19 incre~ses and the resistance to the air flow of contaminated air is increased accordingly. Therefore, it is necessary to clean the filter hoses 19 ~rom time to time.
This is effected ln a way ~nown per se so that the indivi~ual filter hoses 19 are subjectedg one after another, to an impact pulse, in a predetermined sequence9 the pulse being effected by a flushing air flow. The flushing air flow from the respective flushing air conduit passes through the passage 23 into the inside of the ~ er hose 19. The hose stretches outwardly and due to the impact acting on the filter material, a desired portion o~ the deposited layer of dust is removed and discharged at the bottom, Durlng the cleaning of one of the filter hoses 19, the other filter hoses 19 remain in filtering operation so that there is no interruption in the vperation of the overall device~
During the filtering operation of the respeoti~e filter hose 19~ the winding 59 (Figure 2j remains ~ree of electric current. Theholding chamber 37 re~ains in a constant communlcation with the flushing air chamber 16 th~ough the ~i' ~, ~

33~
ann~llar s~all clearance 41, so th~t there is the sa~e pressure in both chambers, the pressure correspondin,~ to that ln the pressurized air conduit 31.
The pressurized flushin air enters through the commun-ication opening 65 into ~he communication conduit 64, into the recess 49 and the spent alr condu~t 48 up to the chamber 530 Its action is such tha.t it tends to close the valve member 54. As the upper side 61 of plate 38 has a greater area than the peripheral zone 45 of its bottom side 40, the plate 38 is pressed by a. ~reater force against the inlet 43 o~ flushing air conduit 35, the inlet thus bein~ securely closedO
l~hen the respective filter hose 1.9 is to be cleaned, the control device (not sho~) of the winding 59 subjects the win~ing to an electric current action pulling back the valve member 54 against the force of the spring 55 and against the pressure of the pressurized air p~esent ln the chamber 53.
The pr~sEurized air in theholding chamber 37 can thus ~low in a pulse manner through the communicatlon opening 65, the commlmicat~on conduit 64, the recess 49, the control air ~onduit :.
49 and out through the exhaust conault 57. Thus, the pressure ~;
in the holdingchamber 37 is reduced and the pressure of the flushing air acting at the peripheral zones 45 of the bottom side 40 o~ plate 38 moves the plate 38 in a stroke motion until the communication opening 65 enters the recess 49. Due to the thus effecte* closing o~ the communication opening 65t the air remaining in the holdingchamber 37 is prevented from ~-ente~in~ the spent air condult 48 so that it now acts on the plate 48 by way of deceleratlng effeck, thus preventlng the plate from striking with a great noise a.gainst the housing 33.
The type of the communication opening 65 can be selected so as to achieve the requlred course of the slowing down o~ the plate 38.
- The M ushlng air flows by way o~ an impact wa~e from the ~ 8 -;,~; '~'' ' ~ ; ' ' . . -3L0~ 3S
flushin~ air chamber 1.6 to the pl~te 38, through the inlet 43 into the flushln~ air con~1uit 35 and from there ~nto the inside of the filter hose 19, as cLescribed above~
After a short time, the control dev~ce opens the circuit of the wlnding 59~ The spring 59 presses the valve nember 54 against the inlet ~6 of the exhaust conduit 57 so that the control air conduit is closed. Due to the inflow o~ ~lushin~
air from cha~ber 16 through the annular clearance 41, the pressure in the holdingchamber 37 increases again so that the plate 38 ls now pressed do~nnwardly to again close the inlet 43.
I~ will be observed that in case of a long duratlon of the flushing, ~hich in itself is not desirable due to an increased consumptlon of pressurized air, the pressure in the.buf~er -~:
chamber 37 is again increased due to the closing of the communication opening 65, to press the plate dotnnwardly. As . .
soon as this communication opening 65 is again opened, the air from the ~oldingchamber 37 is reduced in pressure due to the renewed communicat~on with the exhaust conduit 57, thus bringing the plat0 38 into the state of equilibrium~
In the embodiment of ~ig 3, the plate 38 ca~ries a simple ~ :
short cylinder which, with the plate 38 in closed position, i :
does not reach lnto the recess 49~ Pins 72 fi~ed to the housin~
33 are used in guiding the plate 38.
On the opening movement of plate 38, the oyllnder 71 and the recess 49 form an interruption means for the ~low o~
air into the control air conduit 48.
In the embodiment o~ Fig, 4, the portion of the contr air conduit 48 ad~acent the ~u~er chamber 37 is not used as a recess. Separate recesses 82 are provided which are d0signed in the form o~ gas pockets.
The plate 38 carries cylinders 81 which, at the end of the openlng stroke, enter into the recesses 82. Due to the air arrested ~n the closed recesses 82, the cylinders 81 ~ , ~s ., ,~, .. . . . .

~3641~35 co-operæte ~ith recesses 82 to fo~m a stroke bu~fer.
In the embodlment of Flgs. 5 and 6t the housing 11 does not have any flushlng alr chamber. A separake flushlng air chamber ~1 is disposed to the ~side of the filter housing on a support 92. A ~lushing air conduit 9~ communicates into a header 96 extending into the cle~n air plenum 1~ and provided ~ith ~ets 97, ~or slmultaneous cleanlng of an entire row o~ hose fllters 19~ Obviously, a plurality o~ rows of filter hoses 19 is disposed in ~he cleaning compart~ent 14, one after another, so that the flushing air chamber 91 e~tends in a direction perpendicul~r to the plane of the figure, along a deslred length.
The structure and operation of the flushing air vs.lve lol generally corresponds to thàt of ~he embodiment ac&ording to Figures 1 and 2, t.he control valve for closing the control air conduit 48 not belng shown, similar to the representation in Figs. 3 and 4. A major portion of the housin~ 1.03 of the buffer chs.mber 37 is formed by a cylindric wall 104 and bg a cover 105 ~ixedly secured to same, the cover 105 havin~ the recess 49 for receiving the ¢yllndric member 62. The cover 105 ls arranged to be secured by threaded bolts 1.07 to the upper wall 106 of the flushing air chamber 91, so that the ~.
cylindrlc wall 104 protrudes into the flushing air chamber 91.
Such arrangement enables a simple assembly and reduce~ the overall height o~ the device as a ma~or portion of the bu~er chamber 37 is located inside the ~lushing air chamber 91.
Those skilled in the art will readily conceive further embodiments utillzing the present invention. Such embodiments may be more or less different from the embodiments disclosed hereinbefore but would nevertheless fall within the scope of the present invention as defined in the accompanying claims.

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Claims (8)

The embodiments of the present invention in which an exclusive property or privilege is claimed are defined as follows:

1. A flushing air valve for use in a filtering apparatus comprising a plurality of hollow filter members, said flushing air valve being of the type arranged in a housing for flushing at least one of said filter members, said flushing air valve including a flat valve member whose one face is arranged to close by its inner portion a flushing air conduit, the outside portion of said one face of the valve member being arranged to face the interior of a flushing air chamber of said apparatus, said valve member being movable in a holding chamber in a direction generally perpendicular to the said one face under the action of flushing air pressure, said holding chamber being arranged in a permanent communication with the flushing air chamber through at least one restrictor means, said holding chamber further communi-cating with one end of control air exhaust means arranged to be selectively opened or closed by a control valve; said valve mem-ber being a plate whose peripheral edge is closely spaced with respect to a wall of said holding chamber; said valve member being provided with guide means secured to said housing for guiding the movement of said plate in said direction; the surface of said valve member facing said exhaust means forming, together with a portion of said valve housing facing said surface of the valve member, a piston-cylinder arrangement whose piston is adapted to be slidably received in the cylinder of said arrangement

2. A flushing air valve for use in a filtering apparatus comprising a plurality of hollow filter members, said flushing air valve being of the type arranged in a housing for flushing at least one of said filter members, said flushing air valve including a flat valve member whose one face is arranged to close by its inner portion a flushing air conduit, the outside portion of said one face of the valve member being arranged to face the interior of a flusing air chamber of said apparatus, said valve member being movable in a holding chamber in a direction generally perpendicular to the said one face under the action of flushing air pressure, said holding chamber being arranged in a permanent communication with the flushing air chamber through at least one restrictor means, said holding chamber further communi-cating with one end of a control air exhaust means arranged to be selectively opened or closed by a control valve; said valve member being a plate whose peripheral edge is closely spaced with respect to a wall of said holding chamber; said valve member being provided with guide means secured to said housing for guiding the movement of said plate in said direction; the face of said valve member facing said exhaust means being provided with a cylindric member arranged to be received in a recess provided in the valve housing.

3. A valve as claimed in claim 2 wherein the recess in the valve housing is of the type of a blind pocket arranged to co-operate with said cylindric member to form a pneuma-tic stroke buffer means.

4. A valve as claimed in claim 2 wherein the recess forms a portion of said exhaust conduit means near said holding chamber, said recess being arranged to co-operate with said cylindric member to form shut-off means for shutting off the communication between said holding chamber and said exhaust means.

5. A valve as claimed in claims 2 or 4 wherein said cylindric member is permanently received in said exhaust conduit means to form, with the associated portion of said exhaust conduit means, said guide means.

6. A valve as claimed in claims 2 or 4 wherein said cylindric member is permanently received in said exhaust conduit means to form, with the associated portion of said exhaust conduit means, said guide means; said cylindric member including a con-necting conduit whose one end communicates with said exhaust means and whose other end forms an opening in said cylindric member in proximity to said plate, said opening communicating with he holding chamber.

7. A valve as claimed in claims 2 or 4 wherein said holding chamber has a cylindric wall and a cover fixedly secured to same; said cover including said recess for receiving the cylindric member, said recess being provided in a portion of said cover protruding into the interior of said holding chamber, whereby the overall height of said valve is reduced.

8. A valve as claimed in claims 2 or 4, wherein said cylindric member is permanently received in said exhaust conduit means to form, with the associated portion of said exhaust conduit means, said guide means; said cylindric member including a connecting conduit whose one end communicates with said exhaust means and whose other end forms an opening in said cylindric mem-ber in proximity to said plate, said holding chamber having a cylindric wall and a cover fixedly secured to same; said cover including said recess for receiving the cylindric member, said recess being provided in a portion of said cover protruding into the interior of said holding chamber, whereby the overall height of said valve is reduced.