WO2013008226A1

WO2013008226A1 - Carbon filter device and air filter apparatus

Info

Publication number: WO2013008226A1
Application number: PCT/IL2012/000239
Authority: WO
Inventors: Dani REITER
Original assignee: Yarok Bair Protection Industries Ltd.
Priority date: 2011-07-12
Filing date: 2012-06-17
Publication date: 2013-01-17
Also published as: IL214041A0

Abstract

An air filter apparatus may include a carbon filter device comprising an air-pervious pouch filled with granular carbon, condensed between two opposite air-pervious limiters and surrounded by an elastic band exerting a force towards a central axis of the carbon filter device so as to maintain the granular carbon tightly packed, allowing air driven through the granular carbon to be filtered.

Description

CARBON FILTER DEVICE AND AIR FILTER APPARATUS

BACKGROUND OF THE INVENTION

[001] The present invention relates to filters, and more particularly to a carbon filter device and an air-filter apparatus.

[002] Air filter devices are known. Such filters may typically include a granular activated carbon filter and a mechanical filter for filtering and purifying out chemical and biological substances. Such filters may be installed in communication with air supply systems providing clean air to a protected environment, even in case that the outside air is contaminated. The mechanical filter may capture contaminated particles or spray drops, while the activated carbon may adsorb chemical or biological molecules.

[003] A filter module that includes activated carbon filter and mechanical filter may include a filter module and casing. The filter module may be detachable from the casing to enable replacement. In addition, it is desirable that detaching and assembling the filter module be easy and quick to enable a non-professional person to replace the filter module when needed. Hermetical sealing between the filter module and the casing has to be ensured with high level of confidence, even after replacements of filter module, to prevent the possibility of contaminated air from entering into the protected environment.

[004] For example, DE2119856 describes an air purifying assembly in which when both the mechanical filter and the charcoal filter has to be replaced, a door should be fully opened by operating swiveling arms on sides of the assembly and both parts may be removed by sliding-off support bolts from the bracket fitted to the door inside surface.

[005] A filter module may typically include activated carbon in the form of powder or granules, or in the form of a block. Activated carbon in the form of a block is very sensitive to shocks and may crack or even disassemble in response to a physical shock caused by a jolt, vibration, blow or the like. Activated carbon in the form of a block also lacks efficiency due to a bonder used to hold carbon particles together as block form.

[006] Granular micro-pores activated carbon typically has a surface area in the range of 500-1 100 m² per gram, available for adsorption of significant quantities of poisonous chemical substances. The carbon granules may have average diameter of around 0.6 mm,12x30 mesh with density of at least 0.6 gr/cm3. The activated carbon may be impregnated with impregnators such as, silver, zinc, copper, molybdenum, and TEDA that may ensure carbon long life and may remove even the smallest molecules, as known in the art. Keeping the granulated activated carbon condensed within the filter module, to ensure that its carbon absorption capabilities will remain stable, is of critical importance. It is desirable that the activated carbon granules remains in a dense state for many years, under changing environmental conditions and under various mechanical loads and deformations, without forming cracks (in the case of a block) within the filter assembly, or without sinking (in the case of carbon granules) when in vertical position. Keeping the granular carbon free particles densely packed prevents internal deformations due to impacts or any other forces that may cause hidden channels to firm inside the carbon body letting contaminated air to flow through.

[007] In CH607933 an air filter is described, in which filter layers are held between two permeable walls through which the air to be filtered passes and which are placed in a support frame. The walls are subjected to the action of springs maintaining the pulverulent or granular material under pressure. Similarly, in DE 4115313 a reduced size filter with an active carbon filter bed that is compressed by spring elements that are subject to pressure from screws.

[008] GB2254017 discloses a respirator filter including an active carbon filter bed placed between two grid assemblies. The filter is made by applying compacting load to the bed through one of the grid assemblies and, while the load is applied, securing the grid assembly to a wall of a canister by injecting a continuous bead of hot melt adhesive into contact with both circumferential rim of the grid assembly and to the wall preventing any gases passing between the rim of the grid assembly and the wall. The solidified bead also maintains the desired compaction of the bed when the load is removed.

SUMMARY OF THE INVENTION

[009] According to some embodiments of the present invention, there is provided a carbon filter, the carbon filter may include an air-pervious pouch filled with granular carbon, condensed between two opposite air-pervious limiters and surrounded by an elastic band exerting a force towards a central axis of the carbon filter device so as to maintain the granular carbon tightly packed, allowing air driven through the granular carbon to be filtered.

[0010] Furthermore, according to some embodiments of the present invention, the granular carbon may be activated impregnated microporous granulated carbon.

[0011] Furthermore, according to some embodiments of the present invention, the carbon may be impregnated with TED A. [0012] Furthermore, according to some embodiments of the present invention, the elastic band may define a narrow waist at a central portion of the elastic band and a perimeter near each the limiters which may be wider than the waist at the central portion of the elastic band

[0013] Furthermore, according to some embodiments of the present invention, the elastic band may define an internal annular space.

[001 ] Furthermore, according to some embodiments of the present invention, the elastic band may be annular.

[0015] Furthermore, according to some embodiments of the present invention, the air filter apparatus may further include a casing including an opening for an air inlet and an opposite opening for an air outlet, wherein the elastic band may be annularly positioned in the casing

[0016] Furthermore, according to some embodiments of the present invention, the elastic band may be supported by two opposite base slots in the casings and the upper shoulder of the elastic band may function as a sealant gasket.

[0017] Furthermore, according to some embodiments of the present invention, the casing dimensions may be between 300 and 500 mm diameter and between 100 and 300 mm height.

[0018] Furthermore, according to some embodiments of the present invention, the air filter apparatus may further include a particulate air filter including an air inlet and an air outlet, wherein the air inlet of the particulate air filter may be attached to the air inlet of the casing and the air outlet of the particulate air filter may be attached to one of the two opposite air- pervious limiters of the carbon filter device, and wherein the particulate air filter may be placed within the casing.

[0019] Furthermore, according to some embodiments of the present invention, the particulate air filter may be a high efficiency particulate air (HEP A) filter or an ultra high efficiency particulate air (UEPA) filter.

[0020] Furthermore, according to some embodiments of the present invention, the air filter apparatus may further include an air filter housing that may include a back cover and a front cover, each may have a opening and each may include a double gasket attached along the opening, wherein the back cover may include an anchoring mechanism, and the front cover may be movable with relation to the back cover, and wherein the front cover may be adapted to be secured to the back cover by locks, wherein the casing may be adapted to be placed within the air filter housing such that an air inlet of casing may be placed by the opening of the back cover such that air is prevented from entering the air filtering housing apart from entering through the air inlet of the casing, by the double gasket.

[0021] Furthermore, according to some embodiments of the present invention, the air filter apparatus may further include a pipe placed within the air filter housing, the pipe may have a side opening and a main opening, wherein the side opening may be connected to the air outlet of the casing, and the main opening may be connected to the opening in the front cover, and an electrical motor and a fan installed at a second end of the pipe, wherein activating the electrical motor may cause the fan to spin and suck air through the particulate air filter, the carbon filter device and out through the opening in the front cover.

[0022] Furthermore, according to some embodiments of the present invention, removing the front cover may expose the casing whereby the casing can be detached and assembled.

[0023] Finally, according to some embodiments of the invention, the granular carbon is in the form of a block. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The subject matter regarded as the invention is particularly pointed out and distinctly claimed in the concluding portion of the specification. The invention, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:

[0025] Fig. 1 is a schematic diagram illustrating a cross section view of an exemplary filter assembly according to embodiments of the invention;

[0026] Fig. 2 is a schematic diagram illustrating a perspective view of the cross section of exemplary filter assembly according to embodiments of the invention;

[0027] Fig. 3 is a schematic diagram illustrating a front view of exemplary filter assembly according to embodiments of the present invention;

[0028] Fig. 4 is a schematic diagram illustrating a cross section view of an exemplary air filter apparatus state according to embodiments of the present invention;

[0029] Fig. 5 is a schematic diagram illustrating a perspective view of the cross section of exemplary air filter apparatus state according to embodiments of the present invention; [0030] Fig. 6 is a schematic diagram illustrating filter apparatus in closed state according to embodiments of the present invention;

[0031] Fig. 7 is a schematic diagram illustrating a front view of an exemplary air filter apparatus in an opened state, according to embodiments of the present invention; and

[0032] Fig. 8 is a schematic diagram illustrating a side view of exemplary air filter apparatus in an opened state, according to embodiments of the present invention.

[0033] It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0034] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the present invention.

[0035] Reference is made to Fig. 1 which is a schematic diagram illustrating a cross section view of an exemplary filter assembly 26 according to embodiments of the present invention, and to Fig. 2 which is a schematic diagram illustrating a perspective view of the cross section of exemplary filter assembly 26. According to embodiments of the present invention, filter assembly 26 may include a casing 2 enclosing a particulate air mechanical filter 8 attached to a carbon filter device 25. Casing 2 may be, for example, substantially cylindrical.

[0036] Casing 2 may include a handle 24, an air inlet 6 and an air outlet 7. When not in use, air inlet 6 and air outlet 7 may be hermetically sealed with plugs 21 and 20, respectively. Casing 2 may be made of any durable and substantially humidity diffusion free packaging material such as, for example, Polypropylene enforced with glass fiber. According to some embodiments of the present invention, the dimensions of casing 2 may typically range from 300 to 500 mm in diameter, and from 100-200 mm in height, for holding both particulate air mechanical filter 8 and carbon filter device 25. Casing 2 may also include additional 2 layers of dust protective filter fabric, e.g. anti-fractured PET (polyester) organic synthetic fiber, placed on top of particulate air mechanical filter 8 and the other on top of carbon filter device 25.

[0037] Particulate air mechanical filter 8 may be a High Efficiency Particulate Air (HEP A) filter or Ultra high Efficiency Particulate Air (UEPA). Particulate air mechanical filter 8 may include an air inlet and an air outlet. The air outlet of particulate air mechanical filter 8 may be attached to the air inlet of carbon filter device 25. Particulate air mechanical filter 8 may be placed within casing 2, for example, in a square frame. Alternatively, other shapes of frames may be used.

[0038] Carbon filter device 25 may include an air-pervious pouch 28 filled with carbon 1, condensed between two opposite air-pervious limiters 4 and 5, and surrounded by an elastic band 3, wherein elastic band 3 exerts force on the pouched carbon granules of carbon of filter device 25, directed substantially inwardly towards a central axis LI and towards air- pervious limiters 4 and 5, so as to maintain the granular carbon tightly packed. Carbon 1 is arranged between air-pervious limiters 4 and 5 and elastic band 3 such that air driven through carbon 1 may be filtered. The pouched carbon granules may typically include activated impregnated microporous granulated carbon. Alternatively, carbon 1 may be formed as a block.. The activated carbon may be impregnated with impregnators such as, silver, zinc, copper, molybdenum, and TEDA.

[0039] Air-pervious pouch 28 may hold the granules of carbon 1. Air-pervious pouch 28 may be made, for example, of air pervious and flexible material such as Nylon Spandex, for example 20% Spandex known also as Lycra and 80% Nylon Fiber,, with mass per unit area in the range of 170 - 280 gr/SqMeter. Air-pervious pouch 28 may include a mesh with pores whose diameter is smaller than the diameter of the granules of carbon 1 but big enough to enable free air flow through air-pervious pouch 28. Air-pervious pouch 28 may be provided in the form of a cylinder sewed with small zipper (not shown) on one edge to allow filling it or discharging it as necessary. Once air-pervious pouch 28 is filled with the desired quantity of carbon 1, it may stretch extending in one or more directions, owing to its elasticity. The zipper may be then closed and air-pervious pouch 28 placed in position within filter device 25.

[0040] Air-pervious limiters 4 and 5 may be, for example, rounded nets, made of stainless steel or strong plastics, and may be strong enough so as avoid deforming, cracking or braking under the pressure applied on it by the condensed carbon during the tightening of casing 2. The diameter of air-pervious limiters 4 and 5 may be designed to match the inner diameter of casing 2. Air-pervious limiters 4 and 5 may be placed within casing 2, next to edges 3b and 3c of elastic band 3. Air-pervious limiters 4 and 5 and elastic band 3 may define an hourglass shaped chamber 31 (shown in Fig 2) having a narrow waist at a central portion of elastic band 3 and a perimeter near each of air-pervious limiters 4 and 5 which is wider than the waist at the central portion of elastic band 3. For example, elastic band 3 may be annular and may define an internal annular space such as chamber 31. In some embodiments of the present invention, the dimensions of chamber 31 may range from 300 to 500 mm in diameter, and from 60-90 mm in height. The weight of carbon 1 may vary depending on the available space within chamber 31.

[0041] Elastic band 3 may be made for example, of strong rubber such as EPDM rubber (e.g. with strength of, for example, 60-80 Shore), and may present an hourglass outline, with smaller diameter at mid height 3a with relation to its edges 3b and 3c. The height of elastic band 3 may be designed to match the height of chamber 31 and the diameter of elastic band 3 at edges 3b and 3c may match the inner diameter of chamber 31. The diameter of elastic band 3 may be typically reduced by some 15 - 30 mm at middle height 3a. When placing pervious pouch 28 filled with carbon 1 within casing 2 between air-pervious limiters 4 and 5, the tightening of casing 2 together, may create a force that may push carbon 1 body against pervious pouch 28 and against shaped elastic band 3, creating a desired internal force that may keep carbon 1 particles substantially permanently in a dense state. Elastic band 3 may be supported by two opposite base slots 2a and 2b in casing 2. Elastic band 3 may include a flat shoulder 3d at its upper edge. Elastic band 3, and specifically flat shoulder 3d, may also function as a sealing gasket between the parts of casing 2 with flat shoulder 3d placed between the surfaces to seal. Tightening casing 2 together as described hereinabove may provide a secured mechanical closure and air sealing for many years with no need for welding or gluing which are less secure because of existing internal forces and humidity diffusion.

[0042] Pervious pouch 28 may be filled with carbon 1 and placed within casing 2 of carbon filter device 25 between two opposite air-pervious limiters 4 and 5 and be surrounded by elastic band 3, such that when filter device 25 is fully assembled, carbon 1 placed within pervious pouch 28 is condensed to the required density of at least 0.6 gr/cm³' and pervious pouch 28 is isolated from casing 2. Isolating pervious pouch 28 from casing 2 may isolate carbon 1 from outside forces. When filter device 25 is fully assembled, Elastic band 3 may exert a substantially radial force towards a central axis of carbon filter device 25 so as to maintain tight density of carbon 1.

[0043] Securing carbon 1 between two opposite air-pervious lirniters 4 and 5 and elastic band 3 with significant controlled force may keep carbon 1 in a condensed state for many years, under varying environmental conditions and under different mechanical loads and deformations, without forming cracks within carbon 1. Keeping carbon 1 under substantially constant pressure from all directions may prevent carbon 1 from sinking when in vertical position.

[0044] Reference is made to Fig. 3 which is a schematic diagram illustrating a front view of exemplary filter assembly 26 according to embodiments of the present invention. Filter assembly 26 is presented in an assembled state, with air outlet 7 hermetically sealed with plug 20.

[0045] Reference is made to Fig. 4, which is a schematic diagram illustrating a cross section view of an exemplary air filter apparatus 27, to Fig. 5, which is a schematic diagram illustrating a perspective view of the cross section of exemplary air filter apparatus 27, and to Fig. 6, which is a schematic diagram illustrating filter apparatus 27 in a closed state according to embodiments of the present invention.

[0046] Air filter apparatus 27 may include air filter housing 23 for holding filter assembly 26. Air filter apparatus 27 may further include blower 32 attached to filter assembly 26.

[0047] Air filter housing 23 may include back cover 11 and a front cover 12. Back cover 11 and a front cover 12 may each have a round opening with a double gasket 15 attached along the round opening. Back cover 1 1 may be connected to front cover 12 by, for example, hinges 13. Back cover 11 may be adapted to be secured to an air inlet of a protected area, for example by anchoring mechanism 35, and front cover 12 may be movable with relation to back cover 11, for example, about hinges 13. Alternatively, front cover 12 may be detachable from back cover 1 1. Front cover 11 may be adapted to be secured to back cover 11 by, for example, secured locks 16, or by any other applicable method.

[0048] Filter assembly 26 may be placed within air filter housing 23, for example, by clicking it into place. Handle 24 may be used to pull filter assembly 26out for replacement. An air inlet 6 of filter assembly 26 may be placed by the opening of back cover 1 1. Air may be prevented from entering the air filtering housing 23 apart from entering through air inlet 6 of filter assembly 26 by double gasket 15 placed around the opening of back cover 11. [0049] Blower 32 may include a pipe 14 placed within air filter housing 23. Pipe 14 may have a side opening 29, a main opening 33 at one end and a secondary opening 19 at the other end (with removable cover 34). Side opening 29 may be connected to air outlet 7 of filter assembly 26, and main opening 33 and secondary opening 19 may be connected to openings in front cover 12. An electrical motor 17, for example, a 12 VDC 0.2 Amp electrical motor, and fan 18 may be installed at the second end of the pipe. Activating electrical motor 17 may cause fan 18 to spin and blow air in required air rate flow of , for example, between 36 to 50 cubic/ meter per hour, through particulate air filter 8, carbon filter device 25 and out through main opening 33 and the opening in front cover 12. However, in case of electrical power interruption or shut-down, or in case motor 17 and fan 18 are malfunctioning, a stand alone pump or blower (not shown) may be connected to secondary opening 19 for sucking air through filter assembly 26.

[0050] Reference is made to Fig. 7 which is a schematic diagram illustrating a front view of an exemplary air filter apparatus 27 in an opened state, and to Fig. 8 which is a schematic diagram illustrating a side view of exemplary air filter apparatus 27 in an opened state, according to embodiments of the present invention.

[0051] In the embodiment of the present invention presented in Figs. 7 and 8 front cover 12 is movable with relation to back cover 11, about hinges 13. Opening of front cover 12 may expose filter assembly 26 enabling detaching and assembling of filter assembly 26. Filter assembly 26 may be detached by pulling filter assembly 26 away from back cover 11, for example by pulling handle 24, and assembled by inserting it to its place on back cover 1 1. Detaching and assembling of filter assembly 26 may be quick and easy. No tools, nor special knowledge or training may be required, thus unprofessional people may replace filter assembly 26 when needed.

[0052] Air filter apparatus 27 may also include an electrical cord 30 for connecting the electrical motor to the electrical network.

[0053] Embodiments of the present invention may be used for various applications such as wall mounted instrumentation for filtering and purifying air with use of any granular material placed in vertical position that should stay in fixed position from sinking or collapsing or cracking or changing shape.

[0054] While certain features of the invention have been illustrated and described herein, many modifications, substitutions, changes, and equivalents will now occur to those of ordinary skill in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.

Claims

CLAIMS claimed is: An air filter apparatus comprising: a carbon filter device comprising an air-pervious pouch filled with granular carbon, condensed between two opposite air-pervious limiters and surrounded by an elastic band exerting a force towards a central axis of the carbon filter device so as to maintain the granular carbon tightly packed, allowing air driven through the granular carbon to be filtered.

The air filter apparatus of claim 1, wherein the granular carbon is activated impregnated microporous granulated carbon.

The air filter apparatus of claim 2, wherein the carbon is impregnated with TEDA.

The air filter apparatus of claim 1 , wherein the elastic band defmes a narrow waist at a central portion of the elastic band and a perimeter near each the limiters which is wider than the waist at the central portion of the elastic band.

The air filter apparatus of claim 1, wherein the elastic band defines an internal annular space.

The air filter apparatus of claim 1 , wherein the elastic band is annular.

The air filter apparatus of claim 1, further comprising a casing comprising an opening for an air inlet and an opposite opening for an air outlet, wherein the elastic band is annularly positioned in the casing.

The air filter apparatus of claim 7, wherein the elastic band is supported by two opposite base slots in the casings and wherein the upper shoulder of the elastic band functions as sealant gasket.

The air filter apparatus of claim 7, wherein the casing dimensions are between 300 and 500 mm diameter and between 100 and 300 mm height.

The air filter apparatus of claim 7, further comprising:

a particulate air filter comprising an air inlet and an air outlet, wherein the air inlet of the particulate air filter is attached to the air inlet of the casing and the air outlet of the particulate air filter is attached to one of the two opposite air-pervious limiters of the carbon filter device, and wherein the particulate air filter is placed within the casing.

11. The air filter apparatus of claim 10, wherein the particulate air filter is selectable from a list comprising: a high efficiency particulate air (HEP A) filter and an ultra high efficiency particulate air (UEPA) filter.

12. An air filter apparatus of claim 10, further comprising: an air filter housing comprising: a back cover and a front cover, each having a opening and each comprising a double gasket attached along the opening, wherein the back cover comprising an anchoring mechanism, and the front cover is movable with relation to the back cover and wherein the front cover is adapted to be secured to the back cover by locks, wherein the casing is adapted to be placed within the air filter housing such that an air inlet of casing is placed by the opening of the back cover such that air is prevented from entering the air filtering housing apart from entering through the air inlet of the casing, by the double gasket.

13. The air filter apparatus of claim 12, further comprising: a pipe placed within the air filter housing having a side opening and a main opening, wherein the side opening is connected to the air outlet of the casing, and the main opening is connected to the opening in the front cover; and

an electrical motor and a fan installed at a second end of the pipe, wherein activating the electrical motor causes the fan to spin and suck air through the particulate air filter, the carbon filter device and out through the opening in the front cover.

14. The air filter apparatus of claim 10, wherein removing the front cover exposes the casing whereby the casing can be detached and assembled.

15. The air filter apparatus of claim 1, wherein the granular carbon is formed as a block.