DK148705B

DK148705B - REFILLABLE AIR FILTER

Info

Publication number: DK148705B
Application number: DK119279AA
Authority: DK
Inventors: Walter Muecke
Original assignee: Mann & Hummel Filter
Priority date: 1978-04-07
Filing date: 1979-03-23
Publication date: 1985-09-09
Also published as: DK148705C; DE2815081B2; FR2421664B3; DE2815081A1; DK119279A; FR2421664A1

Description

148705 i 5 Opfindelsen angår et tilbageskylleligt luftfilter af den i krav l's indledning angivne art.The invention relates to a back-flush air filter of the kind set forth in the preamble of claim 1.

Et sådant luftfilter er kendt fra beskrivelsen til tysk patent nr. 27 28 252, hvor der findes et omkob-10 lingsventil, der har to ventiltallerkener. Overtryk virker kun på den ene side af den ene ventiltallerken, hvorved der kræves en stor forskydningskraft. Til påvirkning af ventilen anvendes der derfor en tryk- luftcy linder, der med en forholdsvis lav pris kan 15 udvikle store kræfter under et stort slag. Denne trykluftcylinder har dog den betydelige ulempe, at der til drift kræves to forskellige energiarter, nemlig trykluft til cylinderen og elektrisk strøm til en magnetventil til styring af cylinderen.Such an air filter is known from the specification of German Patent No. 27 28 252, wherein there is a switching valve having two valve discs. Overpressure only works on one side of one valve plate, requiring a high shear force. Therefore, a pressure air cylinder is used to actuate the valve, which with a relatively low price can develop large forces under a large blow. However, this compressed air cylinder has the considerable disadvantage that two different types of energy are required for operation, namely compressed air for the cylinder and electric current for a solenoid valve for controlling the cylinder.

2020

Den foreliggende opfindelse tager sigte på at angive et tilbageskylleligt luftfilter af den omhandlede art, ved hvilken den nævnte ulempe er undgået, og dette opnås ifølge opfindelsen ved, at luftfiltret 25 er udformet som angivet i krav l's kendetegnende del.SUMMARY OF THE INVENTION The present invention aims to provide a retractable air filter of the kind in which the said drawback is avoided, and this is achieved according to the invention in that the air filter 25 is designed as defined in the characterizing part of claim 1.

Ved denne udformning opnår man, at der kun kræves forholdsvis små indstillingskræfter til påvirkning 30 af omkoblings ventilen, så at der kan anvendes en elektromagnet.In this embodiment, it is obtained that only relatively small adjusting forces are required to actuate the switching valve so that an electromagnet can be used.

Derved opnår man nødvendigheden af en anden slags energi.Thereby, one obtains the necessity of another kind of energy.

148705 2 1 En særlig enkel opbygning af omkoblingsventilen i luftfiltret kan man opnå ved, at luftfiltret er udformet som angivet i krav 2's kendetegnende del.A particularly simple construction of the switching valve in the air filter can be achieved by the air filter being designed as defined in the characterizing part of claim 2.

5 For at kunne anvende samme omkoblingsventil til blæsere af forskellig størrelse, kan luftfiltret hensigtsmæssigt også være udformet som angivet i krav 3's kendetegnende del. Overskydende luft bliver herved gennem en shuntledning befordret i kredsløb.5 In order to be able to use the same switching valve for different size fans, the air filter may conveniently also be designed as defined in the characterizing part of claim 3. Excess air is thereby conveyed in a circuit through a shunt line.

1010

Opfindelsen forklares nærmere under henvisning til tegningen, på hvilken fig. 1 viser en udførelsesform for det tilbage-15 skyllelige luftfilter i et aksialt snit og skematisk, fig. 2 den ved luftfiltret i fig. 1 anvendte omkoblingsventil i større målestok og 20 i et aksialt snit med to forskellige ventilstillinger, og fig. 3 omkoblings venti len i fig. 2 med to andre ventilstillinger.The invention is further explained with reference to the drawing, in which: FIG. 1 shows an embodiment of the flush-back air filter in axial section and schematically; FIG. 2 shows the air filter of FIG. 1 is used on a larger scale switching valve and 20 in an axial section with two different valve positions; and FIG. 3, the switching valve of FIG. 2 with two other valve positions.

2525

En udskiller 1 til tilførsel af pulverformet eller kornet transportgods til maskiner, der forarbejder formstof, har et hus 2, der ved sin øverste endeside er lukket af et husdæksel 3. I huset 2 udmunder 30 et transportrør 4 til tilførsel af transportgodset fra en ikke vist silo.A separator 1 for supplying powdered or grained transport goods to machines which process plastics has a housing 2 closed at its upper end side by a housing cover 3. In housing 2 30 a conveyor tube 4 for supplying the transport goods from a not shown silo.

Et tilbageskylleligt luftfilter 5 har et som en papirstjerne udformet ringformet filterorgan 10 3 148705 1 med et som skive udformet dæksel 13, der er fastgjort aftætnet til den nederste endeside, og en endeskive 12, der er indspændt af tætnet mellem randen på huset 2 og husets dæksel 3, og som er fastholdt af tætnet 5 ved den øverste endeside af filterorganet. Dette filterorgan 10 omslutter et som et hele med 15 betegnet renluftrum og er under filterdrift gennemstrømmet radialt udefra og indefter. Dækslet 3 og endeskiven 12 begrænser et dækselkammer 9.A retractable air filter 5 has a paper star shaped annular filter member 10 3 with a disc 13 which is fixedly sealed to the lower end side and an end disc 12 which is clamped by the seal between the rim of the housing 2 and the housing of the housing. cover 3, which is retained by seal 5 at the upper end side of the filter means. This filter means 10 encloses one as a whole, designated as clean air space 15 and, during filter operation, flows radially from the outside and inward. The cover 3 and the end disk 12 limit a cover chamber 9.

10 I renluftrummet 15 for filterorganet 10 er en dysevinge 16 lejret koaksialt drejeligt, hvilken vinge består af en central rørstuds 18 og et parallelt med denne anbragt dyserør 20, der er lukket ved 15 sin endeside og gennem et rør 19 står i forbindelse med rørstudsen 18. Dyserøret 20 har flere radialt udefter mod den indre omkreds af filterorganet 10 rettede åbninger 23 til udstrømning af tilbageskylningsluft. Dysevingen 16 omslutter et hulrum 17 20 og opdeler renluftrummet 15 i et med hulrummet 17 identisk første filterkammer 21 og et dysevingen omgivende andet filterkammer 22.10 In the clean air space 15 of the filter member 10, a nozzle vane 16 is mounted coaxially rotatable, which vane consists of a central pipe nozzle 18 and a parallel to this nozzle pipe 20, which is closed at its end side and through a pipe 19 communicates with the pipe nozzle 18. The nozzle tube 20 has a plurality of radially outwards toward the inner circumference of the filter means 10 directed openings 23 for outflow of backwashing air. The nozzle wing 16 encloses a cavity 17 20 and divides the clean air space 15 into a first filter chamber 21 identical to the cavity 17 and a second filter chamber 22 surrounding the nozzle wing.

I den centrale rørstuds 18 rager der ovenfra en 25 tilledning 25 ind, hvis munding danner en tilstrømningsåbning 26. Dysevingen 16 er med sin rørstuds 18 med et glideleje 24 lejret drejelig på tilledningen 25 og med et yderligere ikke vist leje på en til dækslet 13 fastgjort bolt 30. Mellem tilledningen 30 25 og endeskiven 12 er der dannet en ringformet afstrømningsåbning 28.In the central pipe nozzle 18, a lead 25 extends from above, the mouth of which forms an inlet opening 26. The nozzle wing 16 is pivotably mounted on the pipe 25 with a sliding bearing 24 with a sliding bearing 24 and with a further not shown bearing on a cover 13. bolt 30. Between the lead 30 25 and the end disc 12, an annular discharge opening 28 is formed.

En blæser 60 har en sugestuds 61 og en trykstuds 62. En omkoblings vent il 36, der ved hjælp af en 140705 4 1 mellemvæg 37 er opdelt i et første ventilkammer 38 og et andet ventilkammer 39. I det første ventilkammer 38 udmunder en af en indløbsåbning 42 i ventilhuset 36 omsluttet indløbsstuds 46, der er aftætnet 5 forbundet med trykstudsen 62 i blæseren 60 ved hjælp af en gummimuffe 47. Det første ventilkammer 38 har på den øverste endevæg 40 en første udløbsåbning 44, der over gennembrydninger 43 i ventilhuset 36 udmunder i det fri.A blower 60 has a suction nozzle 61 and a pressure nozzle 62. A switching valve 36 which is divided by means of a middle wall 37 into a first valve chamber 38 and a second valve chamber 39. In the first valve chamber 38, one of a inlet port 42 of valve housing 36 enclosed inlet nozzle 46 sealed 5 to pressure port 62 of blower 60 by means of a rubber sleeve 47. First valve chamber 38 has on first upper wall 40 a first outlet port 44 which opens through breakthroughs 43 in valve housing 36 in the open air.

1010

Den første udløbsåbning 44 er omgivet af det første ventilsæde 71. Aksialt heroverfor har mellemvæggen 37 en anden udløbsåbning 45, der er omgivet af et andet ventilsæde 73, og indmunder i det andet ventil-15 kammer 39. Med den nederste endevæg 41 er omkoblings-ventilen 35 fastgjort til husdækslet 3. En forbindelsesåbning 49 i den nederste endevæg 41 udmunder i tilledningerne 25. På denne måde er den anden udløbsåbning 45 forbundet med hulrummet 17 i dysevin-20 gen 16.The first outlet opening 44 is surrounded by the first valve seat 71. Axially opposite this, the intermediate wall 37 has a second outlet opening 45 which is surrounded by a second valve seat 73 and opens into the second valve chamber 39. With the lower end wall 41 the valve 35 attached to the housing cover 3. A connection opening 49 in the lower end wall 41 opens into the conduits 25. In this way, the second outlet opening 45 is connected to the cavity 17 in the nozzle housing 16.

En ventilstang 77 bliver indstillet ved hjælp af magnetiske kræfter fra en strømgennemstrømmmet spole, der er anbragt i en spolehætte 54. Ventilstangen 25 77 har tre modlejer 91, 92 og 93 i form af fjed rende ringe, der indgriber i tilsvarende noter i ventilstangen. Mod modlejet 91 støtter sig en første ventiltallerken 70, der er anbragt forskydeligt på ventilstangen 77, og som hører til den første 30 udløbsåbning 44. På modlejet 92 støtter sig en anden ventiltallerken 72, og som hører til den anden udløbsåbning 45 og har gennemstrømningsåbninger 74. Disse gennemstrømningsåbninger er på den side, der vender bort fra den anden udløbsåbning 45, omgivet af et 148705 5 1 tredie ventilsæde 78, der samarbejder med en tredie ventiltallerken 75, som ligeledes er forskydelig på ventilstangen 77.A valve rod 77 is adjusted by magnetic forces from a current flowing coil disposed in a coil cap 54. Valve rod 25 77 has three counter bearings 91, 92 and 93 in the form of resilient rings which engage corresponding grooves in the valve rod. Against the counter bearing 91 is a first valve disc 70, slidably disposed on the valve rod 77, which belongs to the first outlet port 44. On counter bed 92, a second valve plate 72 resides with the second outlet opening 45 and has flow openings 74. These flow openings are, on the side facing away from the second outlet opening 45, surrounded by a third valve seat 78 which cooperates with a third valve plate 75 which is also displaceable on the valve rod 77.

5 Mellem modlejet 93 og den nederste endevæg 41, gennem hvilken ventilstangen 77 er ført forskydelig, er der anbragt en som skruetrykfjeder udformet tilbagestillingsfjeder 76, der, når der ikke går strøm gennem spolen, trykker ventilstangen 77 tilbage 10 til udgangsstilling. Ved den anden endeside af modlejet 93 findes der en ligeledes som skruetrykfjeder udformet fjeder 79, gennem hvilken ventilstangen 77 er ført i sin længderetning, og som med sin anden endeside ligger an mod den tredie ventiltallerken, 15 så at den anden ventiltallerken 72 under de fleste bedriftsbetingelser med et tredie ventilsæde 78 er trykket mod den tredie ventiltallerken 75. Endelig findes der også en tredie skruetrykfjeder 90, gennem hvilken ventilstangen 77 ligeledes er ført, og som 20 med en endeside ligger an mod den første ventiltallerken 70 og med en anden endeside mod den tredie ventiltallerken 75.5 Between the backrest 93 and the lower end wall 41, through which the valve rod 77 is slidably inserted, is provided a reset spring 76, which, when there is no current flowing through the coil, pushes the valve rod 77 back to its initial position. At the other end side of the backrest 93 there is also a spring-shaped spring 79, through which the valve rod 77 is guided in its longitudinal direction and which with its other end side abuts the third valve plate 15, so that the second valve plate 72 under most operating conditions with a third valve seat 78 are pressed against the third valve plate 75. Finally, there is also a third screw spring 90, through which the valve rod 77 is also passed and which 20 with one end side abuts the first valve plate 70 and with a second end side against the third valve plate 75.

En væg 94 adskiller fra det andet ventilkammer 39 25 et tredie ventilkammer 95, der gennem overstrømningsåbninger 96 i den nederste endevæg 41 og gennem en åbning 6 i dækslet 3 er forbundet med dækselkammeret 9 og over afstrømningsåbningen 28 med det andet filterkammer 22 samt over en overtryksventil 102 30 har forbindelse med det andet ventilkammer 39. En kortslutningsåbning 101 er omgivet af et fjerde ventilsæde 97, mod hvilket der normalt er trykket et over en tap 98 i endevæggen 41 giidelig lejret ventillegeme 99 ved hjælp af en som skruetrykfjeder 148705 6 1 udformet ventilfjeder 100, gennem hvilken tappen 98 er ført.A wall 94 separates from the second valve chamber 39 25 a third valve chamber 95 which is connected through the overflow openings 96 in the lower end wall 41 and through an opening 6 in the cover 3 to the cover chamber 9 and over the flow opening 28 to the second filter chamber 22 as well as over a pressure valve. 102 30 is connected to the second valve chamber 39. A short-circuit opening 101 is surrounded by a fourth valve seat 97, against which a valve body 99 which is securely mounted over a pin 98 in the end wall 41 is normally pressed by means of a valve spring designed as a screw pressure spring. 100 through which pin 98 is passed.

Sugestudsen 61 på blæseren 60 er over en gummimuffe 5 64 forbundet med en udløbsstuds 65, der danner et udløb fra et kammer 67, som er adskilt fra det andet ventilkammer 39 ved hjælp af en væg 66 og er forbundet med dækselkammeret 9 over en åbning 69 i den nederste endevæg 41 og over åbningen 7 i dasks let 3.The suction nozzle 61 on the fan 60 is connected over a rubber sleeve 5 64 to an outlet nozzle 65 which forms an outlet from a chamber 67 which is separated from the second valve chamber 39 by a wall 66 and is connected to the cover chamber 9 over an opening 69 in the lower end wall 41 and above the opening 7 in the lightweight 3.

1010

Under filterdrift svarende til den i fig. 2 på højre side viste stilling af omkoblingsventilen 35 går der strøm gennem spolen i spolehætten 54, hvorved ventilstangen 77 med de til den fastgjorte dele 15 er trukket ned i den nederste endestilling. Den tredie ventiltallerken 75 ligger an mod det tredie ventilsæde 78, tillukker gennemstrømningsåbningerne 74 og virker som medbringer på den anden ventiltaller-ken 72, som den trykker mod det andet ventilsæde 20 73. Den første ventiltallerken 70 er løftet op fra det første ventilsæde 71 og har frigivet den første udløbsåbning 44. Blæseren 60 suger nu over sugestudsen 61, udløbstudsen 65, kammeret 67, åbningen 69 i den nederste endevæg 41 i ventilhuset 36, åbningen 25 7 i dækslet 3, dækselkammeret 9, afstrømningsåbningen 28, det andet filterkammer 22 og radialt udefra og indefter gennem filtermidlet 10 luft til fra huset 2 i udskilleren 1.During filter operation similar to that of FIG. 2 on the right-hand side of the switching valve 35, current flows through the coil in the coil cap 54, whereby the valve rod 77 with the parts 15 attached to it is pulled down into the lower end position. The third valve plate 75 abuts the third valve seat 78, closes the flow openings 74 and acts as a carrier on the second valve plate 72 as it presses against the second valve seat 20 73. The first valve plate 70 is lifted from the first valve seat 71 and has released the first outlet opening 44. The fan 60 now sucks over the suction nozzle 61, the outlet nozzle 65, the chamber 67, the opening 69 of the lower end wall 41 of the valve housing 36, the opening 25 7 of the cover 3, the cover chamber 9, the flow opening 28, the second filter chamber 22 and radially from the outside and enters through the filter means 10 air from the housing 2 in the separator 1.

30 Det undertryk, der således opstår, bevirker, at transportgods gennem transportrøret 4 suges ind i udskilleren. Derved vil fine partikler i transportgodset afsætte sig på den ydre omkreds af filterorganet 10. Den afsugede luft bliver over trykstudsen 7 148706 1 62 i blæseren 60, indløbsstudsen 46, det første ventilkammer 38, den første udløbsåbning 44 og gennem-brydninger 43 blæst ud i det fri.The negative pressure thus created causes the transport goods through the transport pipe 4 to be sucked into the separator. Thereby, fine particles in the cargo will settle on the outer circumference of the filter means 10. The suction air is blown out over the pressure nozzle 7 of the fan 60, the inlet nozzle 46, the first valve chamber 38, the first outlet opening 44 and the breakthroughs 43. the free.

5 Skal transporten afbrydes og filterorganet 10 renses, bliver den strøm, der går gennem magnetspolen, afbrudt, og tilbagestillingsfjederen 76 trykker ventilstangen 77 opefter. Derved indstiller der sig først den i fig. 3 til venstre viste tilstand af omkoblings-10 ventilen 35, ved hvilken den tredie ventiltallerken 75 imod det på den virkende differenstryk bliver løftet lidt op fra det tredie ventilsæde 78. Derefter kan luft fra det første ventilkammer 38 over gennemstrømningsåbningerne 74 nå ind i det andet ventilkam-15 mer 39 og udligne det der tilstedeværende undertryk.5 If the transport is to be interrupted and the filter means 10 is cleaned, the current passing through the magnetic coil is interrupted and the reset spring 76 pushes the valve rod 77 upwards. In this way, the arrangement shown in FIG. 3 to the left of the switching valve 35, at which the third valve plate 75 against it at the acting differential pressure is lifted slightly up from the third valve seat 78. Thereafter, air from the first valve chamber 38 above the flow openings 74 can enter the second valve chamber 15 and equalize the negative pressure present.

Er luftudligningen sket indtil den forudbestemte størrelse, der afhænger af kræfterne i tilbagestillingsfjederen 76 og i fjederen 79 samt af det på 20 den anden ventiltallerken 72 virkende differenstryk, løfter fjederen 79 den anden ventiltallerken 72 op, indtil den med det tredie ventilsæde 78 ligger an mod den tredie ventiltallerken 75, hvorved gennemstrømningsåbningerne 74 er afspærret. Tilbagestil-25 lingsfjederen 76 kan nu trække ventilstangen 77 tilbage til den i fig. 1 og 2 til venstre viste udgangsstilling, ved hvilken den første udløbsåbning 44 er lukket ved hjælp af den første ventiltallerken 70, medens den anden udløbsåbning 45 er åben. Derefter 30 bliver luft fra blæseren 60 gennem trykstudsen 62, indløbsstudsen 46, det første ventilkammer 38, den anden udløbsåbning 45, det andet ventilkammer 39, forbindelsesåbningerne 49 og tilledningen 25 for trykket ind i hulrummet 17 i dysevingen 16. Luften 8 H070& 1 forlader dysevingen 16 gennem åbningerne 23 og går tværs gennem filterorganet 10 radialt indefra og udefter, idet partikler, der er afsat på den ydre omkreds, bliver løsgjort. Ved en passende anbringelse 5 af åbningerne 23 eller ved hjælp af ekstra åbninger, der peger i retning af omkredsen, er der sørget for, at dysevingen drejer sig efter et reaktionsprin-. cip. Den i -området for åbningerne 23 indefra og udefter gennem filterorganet 10 blæste luft passerer 10 filterorganet 10 på et andet sted radialt udefra og indefter og strømmer gennem afstrømningsåbningen 28, dækselkammeret 9, åbningerne 7 i dækslerne 3 og 69 i den nederste endeside 41 af ventilhuset 36 samt gennem kammeret 67, udløbsstudsen 65 og 15 sugestudsen 61 atter tilbage til blæseren 60. Luften transporteres således i kredsløb.If the air is equalized to the predetermined size, which depends on the forces in the reset spring 76 and in the spring 79 and on the differential pressure acting on the second valve plate 72, the spring 79 raises the second valve plate 72 until it is in contact with the third valve seat 78. the third valve plate 75, whereby the flow openings 74 are blocked. The reset spring 76 can now retract the valve rod 77 to the one shown in FIG. 1 and 2 to the left of the starting position at which the first outlet opening 44 is closed by the first valve plate 70, while the second outlet opening 45 is open. Thereafter 30, air from the fan 60 is passed through the pressure nozzle 62, the inlet nozzle 46, the first valve chamber 38, the second outlet opening 45, the second valve chamber 39, the connection openings 49 and the conduit 25 for pressure into the cavity 17 of the nozzle wing 16. The air 8 H070 & 1 leaves the nozzle wing 16 through the openings 23 and traverses the filter means 10 radially from the inside to the outside as particles deposited on the outer circumference are detached. By a suitable arrangement 5 of the openings 23 or by means of additional openings pointing in the direction of the circumference, the nozzle wing is arranged to rotate according to a reaction principle. CIP. The air blown in the region of the openings 23 inside and out through the filter means 10 passes the filter means 10 at a different location radially from the outside and inwards and flows through the discharge opening 28, the cover chamber 9, the openings 7 in the covers 3 and 69 in the lower end side 41 of the valve body. 36 and through chamber 67, outlet nozzle 65 and 15 suction nozzle 61 back again to fan 60. The air is thus transported in circulation.

Overtryksventilen 102 åbner, når en forudbestemt størrelse af differenstrykket i et rum mellem tryk-20 studsen 62 og dysevingen 16 bliver overskredet i forhold til et rum mellem dysevæggen 16 og sugestudsen 61. Ved den viste udførelsesform for luftfiltret forbinder overtryksventilen 102 det andet ventilkammer 39 over et tredie ventilkammer 95, overstrømningsåb-25 ningen 96 i den nederste endevæg 41 i ventilhuset 36 og åbningen 6 i dækslet 3 med dæks elkammeret 9. Overskydende luft, der f.eks. kan være for hånden på grund af en blæser 60, der er dimensioneret for stor, bliver gennem kortslutningsventilen 102 uden 30 om dysevingen 16 fra sugestudsen 62 over indløbsstudsen 46, det første ventilkammer 38, det andet ventilkammer 39 og det tredie ventilkammer 95 fra dækselkammeret 9 gennem kammeret 67, udløbsstudsen 65 og sugestudsen 61 transporteret til blæseren 60. På 148705 9 1 denne måde er der sørget for, at der gennem udløbsåbningen 23 på trods af en tilslutning af forskellige blæsere 60 altid kan strømme luft med i det mindste tilnærmelsesvis samme mængde og hastighed ud. Desuden 5 forbliver trykforholdene inden i omkoblingsventilen 35 konstante, så at der kan anvendes samme omkoblingsventil med forskellige blæsere.The overpressure valve 102 opens when a predetermined amount of differential pressure in a space between the pressure nozzle 62 and the nozzle wing 16 is exceeded relative to a space between the nozzle wall 16 and the suction nozzle 61. In the illustrated embodiment of the air filter, the overpressure valve 102 connects the second valve chamber 39 over a third valve chamber 95, the overflow opening 96 in the lower end wall 41 of the valve housing 36 and the opening 6 of the cover 3 with the cover electric chamber 9. Excess air, e.g. may be handy due to a fan 60 which is sized too large, through the short-circuit valve 102 without 30 about the nozzle blade 16 from the suction nozzle 62 over the inlet nozzle 46, the first valve chamber 38, the second valve chamber 39, and the third valve chamber 95 from the cover chamber 9. through the chamber 67, the outlet nozzle 65 and the suction nozzle 61 conveyed to the fan 60. In this way, it is ensured that, through the outlet opening 23, despite a connection of different fans 60, air can always flow with at least approximately the same amount. and speed out. In addition, the pressure conditions within the switch valve 35 remain constant so that the same switch valve with different fans can be used.

Claims

1. Rinse-back air filter, in particular for the purification of waste air from pneumatic conveyors, with an annular filter means which, during filter operation, is radially flowed from the outside and inward and during the rinsing operation, sectionally from the inside and outside 10, which encloses a clean air space divided into a first filter chamber and another filter chamber and is connected to one end side and. the other end side is provided with inflow openings and discharge openings, and with a fan whose suction nozzle 15 is connected to a filter chamber and whose pressure nozzle during filter drift is connected to the surroundings, the first filter chamber being formed by a cavity in a coaxial bearing, the clean air space rotatable nozzle wing with multiple inserts directed towards the filter means 20 openings for outflow of flushing air, and the suction nozzle of the fan connected to the second filter chamber surrounding the nozzle blade, and with a switching valve for optional switching on filter operation or back flushing operation, which has a valve with a pressure valve the inlet opening connected to the fan, one opening outlet open in the open and one connected to the second outlet opening with the cavity in the nozzle wing, where there are venting elements which during filter operation only hold the second outlet opening and during back rinse operation only the first outlet opening closed, characterized; in that the shut-off valve (35) is designed as a lifting valve and as a valve element has a first valve disc (70) and a first valve seat (71) and a second valve plate (72) which is associated with the first outlet opening (44) and belongs to the second coaxial opposite outlet opening (45) and provided with flow openings (74) and a second valve seat (73), and between these valve counters (70, 72) a third valve plate (75) for closing the flow openings (74) and a common valve rod (77) movable from a back flush position against the force of a resilient spring (76) supported on rigid valve parts axially to a filter position, and on which the first valve plate (70) is fixed, the third valve plate (75) is secured as a carrier for the second valve plate (72), through which the valve rod (77) is slidably guided and which is loaded by a spring supported on the valve rod (77) there (79) on the third valve plate (75).

1. PATENT REQUIREMENTS

A back-flush air filter according to claim 1, characterized in that the first valve plate (70) and the third valve plate (75) are slidable on the valve rod (77) and passed on one of the valve rod (77) between the valve plates (75, 70). screw spring (90) is adapted to be pressed against counter bearings (91, 92) on the valve rod (77).

Refillable air filter according to claim 1 or 2, characterized in that a space flowed back between the pressure nozzle (62) and the nozzle wing (16) is connected to a space flowed between the nozzle wing (16) and the suction nozzle (61). a short circuit opening (101) controlled by a valve body (99) in an overpressure valve (102),