GB1592929A

GB1592929A - Selfcleaning filter

Info

Publication number: GB1592929A
Application number: GB1995378A
Authority: GB
Original assignee: Interfiltre SA
Current assignee: Interfiltre SA
Priority date: 1977-05-23
Filing date: 1978-05-16
Publication date: 1981-07-15
Also published as: FR2391758B1; FR2391758A1; DE2821960A1

Description

(54) IMPROVEMENTS IN OR RELATING TO A SELF CLEANING FILTER (71) We, INTERFILTRE S.A., a French body corporate, of Hameau de Fervaques -14 140 Livarot. France, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: The present invention relates to a selfcleaning air filter and in partcular to a filter which can be of simplified -and cheap construction so that it is of particular interest for medium-size ventilation or air conditioning plants, devices, systems or like arrangements. By "self-cleaning" we mean that the filtering element or elements do not need to be detached for cleaning and that cleaning is accomplished without direct manual intervention.

In known mechanical filters the gas to be purified is passed by means of a forceddraught ventilation through one or several panels made from fibrous material. Such filters are very effective but they require periodical cleaning in order to remove the impurities which would otherwise gather or collect in the superficial layers of the fibrous material and which would significantly increase the resistance to the flow of gas therethrough after long periods of use. Therefore such filters are often fitted with sprinkling or spraying devices which wash the filtering panels on the spot. In large plants the sprinkling or spraying device may be in the form of a sprinkling or spraying piping which may be moved in a translatory motion, incorporated into the filter frame and moving back and forth along the filtering panels. Such a structure is however expensive to manufacture and is therefore not useful in small plants. Filters for small plants do not have any sprinkling or spraying arrangement but merely a filter element structure provided as a continuous strip, sheet or web of filtering material wound or stored as a roll or coil and adapted to be gradually unwound inside of a filtering box or casing as it becomes clogged, fouled or dirty. While such a construction is simpler and results accordingly in lower installation expenses, the maintenance costs are however relatively high since it is necessary periodically to change or replace the roll or coil of filtering material when the latter is fully clogged or fouled.

The present invention can provide a selfcleaning air filter structure with nondetachable filtering panels and with a sprinkling or spraying device of simple and advantageous design so that its manufacturing cost is comparable with those of filters provided with a strip, sheet or web of fibrous material while the main advantage of the filters fitted with a sprinkling or spraying device. namely that operating costs are very low, is retained.

This result can be achieved because instead of the translatory motion of the known sprinkling or spraying devices, there is provided a simple reciprocating rotary or pivoting motion of the sprinkling pipe nozzle.

Thus, according to the present invention, there is provided a self-cleaning air filter comprising at least one filtering panel and a sprinkling device mounted opposite said filtering panel, said sprinkling device including a pipeline provided wih a flexible portion and at least one pivoting tip fitted with at least one spray nozzle and mounted at the end of the flexible portion, said pivoting tip being connected to a transmission system for reciprocating motion, said transmission system being adapted for imparting a reciprocating pivoting motion to the tip thereby enabling a jet of liquid issuing from the spray nozzle to sweep at least one predetermined area of said filtering panel, said flexible portion enabling the pivoting motion of said tip. Preferably the pivoting tip is operatively coupled to a drive shaft of a control motor, so that the motor activates the pivoting tip.

To make the structure of the sprinkling device as simple as possible, the pivoting tip is mounted at the end g a flexible or yielding portion, which may be made for example from rubber, of a pipeline of the sprinkling device; said flexible or yielding portion thus constituting the pivotal con necting or swivel means of said pivoting tip. Moreover the spray-nozzle or nozzles is or are preferably shaped to as to supply a jet of liquid as wide as possible so that the number of pivoting tips required for sweeping the whole surface of the filtering panel or panels may be minimised.

Embodiment of the present invention will now be described by way of example, with reference to the accompanying drawing, in which: Figure 1 is a diagrammatic view of the filter in cross-section taken upon the line I-I of Figure 2, i.e. parallel to the direction of flow of the gas to be purified; and Figure 2 is a perspective view showing the same filter.

Referring to the drawing, the self-cleaning filter consists of a metal box or casing 11 of substantially rectangular parallelepipedic shape, two filtering panels 12, and a sprinkling device 13 mounted in front of these filtering panels. The box or casing 11 has two ppposite open faces 14 and 15 so that it forms a ventilation duct portion inside which the flowing gas is purified by passing through the filtering panels 12. The latter are mounted transversely relative to the direction of gas flow and they are inclined within the box 11 so as to increase the operative filtering surface area. The sprinkling device 13 comprises a safety or cut-off valve 16 and two flexible pipe or hose portions 17 and 18 made, for example, from rubber and each joined to a pivoting tip, 19 and 20, respectively. Each pivoting tip is fitted with a spray nozzle 21 directed or pointing towards the respective filtering panel 12. The pivoting tips 19 and 20 are mechanically operated by a transmission system 22, which is itself coupled to the drive shaf 23 of a control motor 24. Thus each pivoting tip 19 or 20 is secured to a cross-beam or like transverse member 19a or 20a extending across and inside the frame 11 with respect to the direction of flow of the gas to be purified. Each cross-member 19ai 20a (which preferably consists of a piece of L-shaped strucural section as shown in the figures) is adapted to turn or revolve about its longitudinal axis in end journal bearings 26 connecting the cross mcmbers to the side walls 27 and 28 of the frame 11. The transmission system 22 comprises a linkage consisting of a connecting rod 30 and of a crank 31 connecting the drive shaft 23 of the motor 24 to the transversely extending cross member 20a and to the transversely extending cross member l9a (and is connected to the latter by means of an intermediate connecting rod 32). Thus the transmission system comprises three pivotal connections 33,34,35.

The pivotal connecion 33 forms the linking means between the crank 31 and the connecting rod 30. The pivotal connection 34 provides the linking means between the connecting rod 30, the intermediate connecting rod 32 and a small connecing rod 36 secured to the transversely extending cross member 20 and forming a pivoting lever. Finally the pivotal connection 35 forms a link means between the intermediate connecting rod 32 and a small connecting rod 37 secured to the transversely extending cross-member 19a and also forming a pivoting lever.

The motor 24 may be an electric motor but alternatively it may be a hydraulic motor. In this case it is preferably mounted in series in the water feed circuit of the sprinkling device 13, for example between the valve 16 and the flexible hose sections 17 and 18 (according to an alternative embodiment not shown). In this manner all electric circuitry is omitted or may be dispensed with inside of the casing or box.

The operation of the filter according to the invention is very simple. Periodically, when the resistance to the gas ftow is growing excessively large in view of the collection or gathering of dirt in the filtering panels 12, the ventilation is discontinued for a short time and cleaning or washing liquid is fed into the sprinkling device 13.

The motor 24 is energized and the transmission system 22 drives the tips 19 and 20 according to a reciprocating pivoting motion enabling the jets of liquid flowing out of the spray nozzles 21 to sweep over substantially the whole surface of the filtering panels 12. The flexible pipe portions or yielding hose sections 17 and 18 do not interfere with the rotary or revolving motion of the transversely extending crossmembers so that these flexible pipe portions form a particularly simple means for pivotally connecting the pivoting tips to the remainder of the sprinkling device.

WHAT WE CLAIM IS:- 1. A self-cleaning air filter comprising at least one filtering panel and a sprinkling device mounted opposite said filtering panel, said sprinkling device including a pipeline provided with a flexible portion and at least one pivoting tip fitted with at least one spray nozzle and mounted at the end of the flexible portion, said ivoting tip being connected to a transmission system for reciprocating motion, said transmission system being adapted for imparting a reciprocating pivoting motion to the tip thereby enabling a jet of liquid lissuing from the spray nozzle to sweep at least one predetermined area of said filtering panel, said flexible portion enabling the pivoting motion of 4aid tip.

2. A filter according to claim 1 wherein the flexible portion is made of rubber.

3. A filter according to claim I or claim

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. necting or swivel means of said pivoting tip. Moreover the spray-nozzle or nozzles is or are preferably shaped to as to supply a jet of liquid as wide as possible so that the number of pivoting tips required for sweeping the whole surface of the filtering panel or panels may be minimised. Embodiment of the present invention will now be described by way of example, with reference to the accompanying drawing, in which: Figure 1 is a diagrammatic view of the filter in cross-section taken upon the line I-I of Figure 2, i.e. parallel to the direction of flow of the gas to be purified; and Figure 2 is a perspective view showing the same filter. Referring to the drawing, the self-cleaning filter consists of a metal box or casing 11 of substantially rectangular parallelepipedic shape, two filtering panels 12, and a sprinkling device 13 mounted in front of these filtering panels. The box or casing 11 has two ppposite open faces 14 and 15 so that it forms a ventilation duct portion inside which the flowing gas is purified by passing through the filtering panels 12. The latter are mounted transversely relative to the direction of gas flow and they are inclined within the box 11 so as to increase the operative filtering surface area. The sprinkling device 13 comprises a safety or cut-off valve 16 and two flexible pipe or hose portions 17 and 18 made, for example, from rubber and each joined to a pivoting tip, 19 and 20, respectively. Each pivoting tip is fitted with a spray nozzle 21 directed or pointing towards the respective filtering panel 12. The pivoting tips 19 and 20 are mechanically operated by a transmission system 22, which is itself coupled to the drive shaf 23 of a control motor 24. Thus each pivoting tip 19 or 20 is secured to a cross-beam or like transverse member 19a or 20a extending across and inside the frame 11 with respect to the direction of flow of the gas to be purified. Each cross-member 19ai 20a (which preferably consists of a piece of L-shaped strucural section as shown in the figures) is adapted to turn or revolve about its longitudinal axis in end journal bearings 26 connecting the cross mcmbers to the side walls 27 and 28 of the frame 11. The transmission system 22 comprises a linkage consisting of a connecting rod 30 and of a crank 31 connecting the drive shaft 23 of the motor 24 to the transversely extending cross member 20a and to the transversely extending cross member l9a (and is connected to the latter by means of an intermediate connecting rod 32). Thus the transmission system comprises three pivotal connections 33,34,35. The pivotal connecion 33 forms the linking means between the crank 31 and the connecting rod 30. The pivotal connection 34 provides the linking means between the connecting rod 30, the intermediate connecting rod 32 and a small connecing rod 36 secured to the transversely extending cross member 20 and forming a pivoting lever. Finally the pivotal connection 35 forms a link means between the intermediate connecting rod 32 and a small connecting rod 37 secured to the transversely extending cross-member 19a and also forming a pivoting lever. The motor 24 may be an electric motor but alternatively it may be a hydraulic motor. In this case it is preferably mounted in series in the water feed circuit of the sprinkling device 13, for example between the valve 16 and the flexible hose sections 17 and 18 (according to an alternative embodiment not shown). In this manner all electric circuitry is omitted or may be dispensed with inside of the casing or box. The operation of the filter according to the invention is very simple. Periodically, when the resistance to the gas ftow is growing excessively large in view of the collection or gathering of dirt in the filtering panels 12, the ventilation is discontinued for a short time and cleaning or washing liquid is fed into the sprinkling device 13. The motor 24 is energized and the transmission system 22 drives the tips 19 and 20 according to a reciprocating pivoting motion enabling the jets of liquid flowing out of the spray nozzles 21 to sweep over substantially the whole surface of the filtering panels 12. The flexible pipe portions or yielding hose sections 17 and 18 do not interfere with the rotary or revolving motion of the transversely extending crossmembers so that these flexible pipe portions form a particularly simple means for pivotally connecting the pivoting tips to the remainder of the sprinkling device. WHAT WE CLAIM IS:-

1. A self-cleaning air filter comprising at least one filtering panel and a sprinkling device mounted opposite said filtering panel, said sprinkling device including a pipeline provided with a flexible portion and at least one pivoting tip fitted with at least one spray nozzle and mounted at the end of the flexible portion, said ivoting tip being connected to a transmission system for reciprocating motion, said transmission system being adapted for imparting a reciprocating pivoting motion to the tip thereby enabling a jet of liquid lissuing from the spray nozzle to sweep at least one predetermined area of said filtering panel, said flexible portion enabling the pivoting motion of 4aid tip.

3. A filter according to claim I or claim

2 wherein the pivoting tip is operatively coupled to a drive shaft of a control motor to be actuated thereby.

4. A filter according to any one of the preceding claims including a supporting frame forming a ventilation duct portion, wherein said pivoting tip is secured to a cross-member extending substantially transversely to the direction of gas flow within said frame and adapted to turn or revolve about its longitudinal axis owing to the provision of a pair of end journal bearings connecting said cross-member to said supporting frame.

5. A filter according to claim 4 characterized in that said transversely extending cross-member exhibits the general shape of an angle-shaped structural section.

6. A filter according to claim 5 when dependent on claim 3 wherein said transmission system comprises a linkage with a connecting rod and a crank connecting the drive shaft of said control motor to said transversely extending cross-member.

7. A filter according to claim 5, when dependent on claim 3, or claim 6 wherein said control motor is a hydraulic motor mounted in series in the liquid feed circuit of said sprinkling device.

8. A filter substantially as described herein with reference to and as shown in the accompanying drawings.