Gas separation: apparatus – With timing or changeable programming means – Of cleaning mechanism for separating media
Reexamination Certificate
1999-10-19
2001-11-27
Smith, Duane (Department: 1724)
Gas separation: apparatus
With timing or changeable programming means
Of cleaning mechanism for separating media
C055S294000, C055S302000, C055S490000, C055S283000, C095S026000, C095S279000
Reexamination Certificate
active
06322618
ABSTRACT:
FIELD OF INVENTION
This invention relates to the collection and removal of fumes, dust and similar material, and particularly, to a removal apparatus which is controllably movable. The invention further relates to a filter assembly with a backwash cleaning modality.
BACKGROUND OF THE INVENTION
The collection and removal of unwanted material, such as noxious fumes, dust and the like, can be obtained by the use of ducting having a collecting valve capable of being positioned adjacent to a source of unwanted material, the ducting connected to an abstraction system. Some of the uses of such removal devices include welding operations, grinding machines, laboratory operations which can produce fumes from chemical reactions, and surgical operations. Such devices typically comprise a duct assembly having a collecting mouth or inlet at one end, and a connection to an abstraction fan at the other. The assembly has some flexibility so that the collecting mouth or inlet can be stationed at any desired position. The assembly usually needs to be periodically repositioned and some form of support arrangement is required to retain the assembly in any given orientation and to permit easy movement and repositioning. Once repositioned the assembly should retain the new orientation and not be subject to undesirable movement. The mouth or inlet is normally movable in any direction in a plane and also movable in and out of such plane.
Various arrangements exist providing an adjustable assembly, including the provision of internal or external jointed frames which support the duct. Various devices such as lifting or position-balancing means, such as springs and other devices can be used, together with frictional means at joints.
Canadian Patent number 973,012 (Nederman) discloses a folding duct assembly having an internal duct support extending substantially the length of the duct. The duct support comprises a jointed arm having spring counterbalances to counter the weight of the duct. The joints of the duct support incorporate friction pads to retain the duct in a desired position. Jointed duct support structures are also shown in U.S. Pat. No. 5,527,217 (Engstrom) and U.S. Pat. No. 4,860,644 (Kohl et al). In the Kohl et al device, the joints incorporate friction pads to restrict their mobility, while the joints in Engstrom are linked to a retainer wire that in turn is held in place by a friction fit.
It is desirable, and in most cases essential, that there is provided means for holding the duct assembly in position during use, while still permitting easy movement to a new position. These conflicting requirements are difficult to satisfy with friction type joints. Wear at the joints will interfere with acceptable operation and regular adjustment will be required. If the support structure or frame is housed within the ducts of the assembly, such adjustment becomes very difficult. Also, the action of the friction joints can be adversely affected by the material being extracted through the ducts.
In a further aspect, the typical dust or contaminant removal apparatus includes a filter arrangement, whereby the contaminated air is purified before discharge from the apparatus. A typical filter comprises a hollow cylindrical structure having a folded paper filter element. This type of filter is characterized by inconsistent spacing between the filter pleats, resulting in difficulty in removing dust and dirt lodged within the filter. This reduces the life-span and efficiency of the filter. Accordingly, the use of a planar filter element is desirable. Further, it is desirable to provide a means whereby the filter may be automatically cleaned, without removal of the filter from the apparatus. A typical filter-cleaning arrangement is disclosed within U.S. Pat. No. 5,322,535 (Simms), relating to an apparatus for cleaning a hollow cylindrical air filter. The arrangement comprises a travelling nozzle, which both rotates and travels axially relative to the filter, thereby backwashing the filter with a narrowly directed stream of air moving in a countervailing direction to the normal direction of flow. This arrangement is limited for use with a hollow cylindrical filter, and is not capable of use with a planar filter arrangement. In general, it is desirable to provide a moving nozzle arrangement for directing a narrow air stream against the filter for backwash cleaning, rather than an air stream which covers the entire filter simultaneously, as a more efficient backwash cleaning means.
SUMMARY OF THE INVENTION
The present invention provides a ducting assembly for collection and removal of material, comprising an assembly comprising a plurality of duct sections and a duct support. A first duct has a collection inlet at an inlet end, an outlet end connected to an inlet end of a second duct. The outlet end of the first duct is connected to the inlet end of the second duct by the duct support. The duct support comprises at least two elongate arms, pivotally connected, a first arm attached to the first duct at the outlet end and the second arm attached to the second duct at the inlet end. Extending from the first arm beyond the pivot connection is a counterbalance arm weighted such as to counterbalance the first duct and any associated inlet device, such as a hood or the like. The adjacent ends of the ducts are connected in an air-tight manner by flexible ducting. The outlet end of the second duct is movably mounted by duct support means, which again can comprise two pivotally connected elongate arms. Counterbalancing of the duct assembly can be by an air piston or air spring assembly.
In a further aspect, the invention comprises a filter assembly having filter cleaning means. The assembly comprises a filter housing, at least one generally planar filter element, and a cleaning means for directing a gas flow against the filter element for backwash cleaning. In order to provide complete or substantially complete coverage of the filter, while still permitting a relatively forceful air blast, the cleaning means comprises a nozzle, linked to a compressed gas supply, directed at the filter. The nozzle is mounted for movement relative to the filter, along two axes within a plane parallel to the filter. First and second drive means propel the nozzle along the two axes.
Preferably, the filter is vertical, and the nozzle includes drive means to move the nozzle along vertical and horizontal axes, whereby the nozzle describes a generally zig-zag pattern as it shuttles simultaneously or sequentially along the horizontal and vertical axes. The drive means may alternatively move the nozzle in a spiral pattern. The nozzle maintains a constant distance from the filter throughout.
Preferably, dual spaced-apart parallel filter elements are provided, with the cleaning means comprising dual oppositely-facing nozzles mounted to a traveller. The traveller shuttles on a horizontal support, with the support in turn being mounted to and travelling vertically on one or more pillars. Drive means propel the traveller and horizontal support respectively, in reciprocating movement.
A controller controls the reciprocating movement of the traveller and permits an operator to activate the cleaning means on a periodic basis.
REFERENCES:
patent: 807480 (1905-12-01), Mathis
patent: 3147098 (1964-09-01), Honan et al.
patent: 3303635 (1967-02-01), Sherrill
patent: 3339348 (1967-09-01), Bratton
patent: 3555785 (1971-01-01), Wooldridge et al.
patent: 4240809 (1980-12-01), Elsbernd et al.
patent: 4860644 (1989-08-01), Kohl et al.
patent: 5281246 (1994-01-01), Ray et al.
patent: 5322535 (1994-06-01), Simms et al.
patent: 5336130 (1994-08-01), Ray
patent: 5482505 (1996-01-01), Hedlund
patent: 5527217 (1996-06-01), Engström
patent: 5536206 (1996-07-01), Bodmer et al.
patent: 973012 (1975-08-01), None
Boudreault Robin
Finauri Marco
Simms Maury
Greene Jason M.
Smith Duane
Texas Electroniques Canada Inc.
Zahl Adrian
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