CN102696284A - Air filter - Google Patents

Abstract

An air filter unit (20) configured for attachment to an external wall of an enclosure, the air filter unit comprising an inlet (21 ) at a base of the unit; a filter (23) formed by a passageway extending from the inlet and lined with bristles extending across the passageway along at least a portion of the passageway length; an outlet (28); and a heat exchanger (24) disposed between the filter and the outlet such that air passing through the inlet and filter passes through the heat exchanger prior to exiting the unit through the outlet, wherein the air filter unit is configured for attachment such that the heat exchanger is disposed above the filter in use.

Description

air filter

technical field

The present invention relates to an air filter for ventilation and temperature control of, for example, electrical equipment cabinets.

Background technique

The enclosures of electrical equipment often require ventilation to allow the equipment to dissipate excess heat to the outside environment to avoid overheating. In applications where electrical equipment is used in remote locations such as mobile radio communication base stations, the equipment is often left unattended for long periods of time. Additional cooling and ventilation are often required to ensure that the temperature of the equipment remains within the preferred temperature range. Depending on their complexity, such cooling equipment consumes energy, is expensive and sometimes in limited supply, and also requires maintenance to avoid a high risk of failure.

Another approach for cooling electrical equipment is disclosed in published PCT application WO 2009/090405, which uses air conditioning or large fans to provide cooling. An exemplary embodiment of this application is shown in FIG. 1 and includes a chamber or box 110 having an air filter unit 70 mounted on an outer wall 120 for filtering air drawn into the box (indicated by arrow 75), the air is used to cool the electrical equipment in the box (for example, in the equipment cabinet 121). The air filter unit 70 comprises a plurality of plates 71 each having outwardly extending bristles, the plates 71 mounted within the unit and aligned vertically, i.e. substantially in the direction of air flow through the filter 70 align. Air outlet 73 extends into interior volume 115 of chamber 110 , allowing air to enter the chamber vertically downwards in the direction indicated by arrow 76 . The air flows vertically upwards through the filter unit 70 and then vertically downwards into the interior volume 115 of the chamber 110 . In some alternative embodiments, an evaporator unit may be connected to the air outlet 73 between the air outlet and the floor of the chamber 110 to provide additional cooling of the air entering the chamber.

Under normal operating conditions, a portion of the dust captured by the filter bristles will simply fall out due to gravity, as the use of larger air inlets reduces the velocity of the air entering the filter to such an extent that the particles are not continuously pushed upwards. The degree of attraction through the filter. Although the air filter arrangement described above is effective in removing suspended particles from the air entering the enclosure, it still requires occasional cleaning of the filter to ensure that the filter does not become clogged, which reduces the efficiency of the filter. Cleaning may eg include "flushing" of the filter material, which generally involves at least partial disassembly of the filter unit. This requires a field trip, which increases the cost of maintaining the equipment enclosure.

Another problem with the prior art air filter units described above is condensation inside the equipment cabinet. The air conditioner unit is installed in the enclosure to cool the air entering the enclosure when required, resulting in the formation of condensation in the enclosure, which affects adjacent electrical equipment and necessitates consideration of the drainage problems.

Another problem relates to the complexity of the installation, especially related to the number of individual items installed to form a working cooling system and the number of holes required in the wall in which the air filter is installed. Installing the air conditioning unit as an additional component requires additional holes through which the pipes from and to the condenser unit need to pass, potentially creating a point where condensation can collect.

Another problem relates to the volume available in the equipment enclosure, which is often very limited and may not be sufficient to accommodate bulky units including built-in air conditioning and air inlets.

Contents of the invention

It is an object of the present invention to address one or more of the above mentioned problems.

According to a first aspect of the present invention there is provided an air filter unit configured for attachment to an outer wall of a cabinet, the air filter unit comprising:

an inlet on the bottom of the unit;

a filter formed by a channel extending from the inlet and arranged with bristles extending transversely through the channel along at least a portion of the channel's length;

export; and

a heat exchanger positioned between the filter and the outlet such that air passing through the inlet and filter passes through the heat exchanger before exiting the unit through the outlet,

Wherein the air filter unit is configured for attachment such that in use the heat exchanger arrangement is located above the filter.

An advantage of the arrangement described above is that the heat exchanger (usually comprising the evaporative unit of the air conditioning system) cools the air that has passed through the filter before it exits through the outlet. Any condensation formed will thus fall back and through the filter, eventually falling out at the bottom out of the outlet of the unit. An additional advantage of this arrangement is that this condensed water provides a cleaning action on the air filter burrs, thereby reducing the need for maintenance surveys. In some embodiments, the heat exchanger may also be configured to, if desired, heat the air passing therethrough.

The evaporator is preferably configured to allow air to pass through the evaporator from the first surface to the opposite second surface. This arrangement ensures maximum usable area for air to pass through the filter unit, reducing the evaporator's blocking effect on the air flow.

The evaporator preferably includes a plurality of fins extending between the first and second opposing surfaces to maximize the surface area available for exchanging heat as air passes through the unit.

The evaporator is preferably arranged directly above the filter to allow condensation forming on the evaporator to fall and pass through the filter.

The air filter unit optionally includes a fan arranged between the outlet and the heat exchanger for drawing air through the filter and heat exchanger and exiting the unit through the outlet . Incorporating the fan into the unit reduces the number of components that need to be installed when installing the air filtration unit, thereby reducing installation costs. In order to reduce the size of the unit, the fan is preferably a centrifugal fan configured to draw air up through the filter and heat exchanger and expel air laterally towards the outlet and into the cabinet.

According to a second aspect of the present invention, there is provided an electrical equipment enclosure comprising an outer wall on which is mounted an air filter unit according to the first aspect of the present invention, said air filter unit being oriented such that said heat An exchanger is arranged above the filter. The heat exchanger is placed above the filter to allow condensation to fall onto and pass through the air filter to provide a cleaning action while solving the previously mentioned problem of condensation inside the box.

According to a third aspect of the present invention, there is provided a method of operating the air filter unit according to the first aspect of the present invention, the air filter unit is attached to the outer wall of the box, the method comprising: sucking air through the An inlet goes inside the unit; air is drawn upwardly from the inlet through the filter and heat exchanger; and air is expelled from the unit through the outlet into the tank. The method preferably includes condensing water vapor from air drawn into said unit over said heat exchanger to form condensation which falls from said heat exchanger through said air filter and through and out of the unit through the inlet. The air filter can thus be cleaned as condensation passes down the unit.

Description of drawings

The invention is now exemplarily described with reference to the accompanying drawings, in which:

Figure 1 shows a known embodiment of an air filter unit installed on an equipment cabinet;

Figure 2a is a first perspective view of an exemplary air filter unit according to the present invention;

Figure 2b is a second perspective view of the exemplary air filter unit of Figure 2a;

Figure 3 is a front view of an exemplary air filter unit according to the present invention;

4 is a cutaway perspective view of an exemplary air filter unit in a mounted configuration.

Detailed ways

The air filter unit and associated equipment housing shown in FIG. 1 have been described above with reference to the background of the invention.

Figures 2a and 2b show an air filter unit 20 according to the invention, with Figure 2a showing an external view of the unit 20 and Figure 2b showing the internal components of the unit 20, which are not visible in use . The unit comprises an air inlet 21 in the form of a grid which allows air to pass freely (indicated by arrow 25a ) and into the inlet plenum (indicated by arrow 25b ) before entering the air filter 23 . The larger air inlet 21 allows air to enter the unit unimpeded at a lower velocity, which reduces the likelihood of inhaling larger dust particles and allows particles captured by the filter 23 to eventually fall out when the unit is operating. out of the unit. The plenum 22 separates the filter 23 from the air inlet 21 to provide a space for material falling from the filter 23 to collect and thus not interfere with the air flow through the unit 20 .

The air filter 23 comprises vertically oriented stacked panels, each panel having bristles extending from one or both sides of the panel. The plate may, for example, be mounted in a slot defined on the interior wall of the filter unit body, or be provided as a separate pre-assembled module for ease of assembly and replacement. A particularly preferred type of air filter is assembled in a plate with turf covering one or both sides of the plate.

Placed above and adjacent to the air filter 23 is a heat exchanger 24 through which the filtered air passes before leaving the unit 20 . The heat exchanger 24 is preferably in the form of an evaporator unit, in particular it is configured to fit in an air filter unit so that air flows vertically upwards through the heat exchanger 24 (indicated by arrow 25c). The air leaving the heat exchanger 24 flows through a centrifugal fan 26 which causes the air to exit the unit laterally through an outlet 28 (indicated by arrow 25d) and into the case to which the unit 20 is attached (see Fig. 4, as described below). Outlet 28 is generally smaller than inlet 21 in practice.

FIG. 3 shows another interior front view of the air filter unit 20 showing the relative position of each component of the unit 20 . The unit 20 includes a flange 27 extending around the outer boundary which allows the unit to be mounted to the flat outer wall of the box.

Fig. 4 shows a cutaway perspective view of an air filter unit 20 according to the invention, the unit 20 being attached to an external support wall 41, for example an external support wall of an equipment cabinet. In this embodiment, the air inlet 21 comprises a grid extending across the bottom surface of the unit 20 which allows dust and condensation to leave the unit while allowing air to enter the unit. The centrifugal fan 26 is installed on the support frame 44 in the air outlet plenum 45 , and the air is blown out by the fan 26 and enters the box through the hole 42 provided in the support wall 41 . The hole 42 can be made substantially smaller than the inlet 21 of the air filter unit 20 since there is no need to slow down the air velocity once the air has passed through the filter 23 and heat exchanger 24 . The filter 23 within the unit 20 is formed by a stack of filter sheets oriented parallel to the support wall 41 .

Other embodiments are intended to be within the scope of the invention as defined by the appended claims.

Claims (10)

1. air filter unit is configured to be used to be attached to the outer wall of casing, and said air filter unit comprises:

Inlet on the bottom of said unit;

Filter is formed by the passage from entrance extension, and is placed with the seta that extends laterally across said passage along at least a portion of said passage length;

Outlet; And

Heat exchanger is placed between said filter and the said outlet, thereby makes the air that passes said inlet and filter leave said unit through said outlet before, pass said heat exchanger,

Wherein said air filter unit is configured to be used for attachment makes in use said heat exchanger layout be positioned at said filter top.

2. air filter unit according to claim 1, wherein said heat exchanger unit comprises the evaporator of air handling system.

3. air filter unit according to claim 2, wherein said evaporator are configured to allow air to pass evaporator from first surface to reach opposing second surface.

4. air filter unit according to claim 3, wherein said evaporator comprise a plurality of fins that between first and second apparent surfaces, extend.

5. according to the described air filter unit of arbitrary claim in the claim 2 to 4, wherein said evaporator directly is arranged in said filter top, falls and pass said filter with the dewfall that allows to be formed on the said evaporator.

6. according to the described air filter unit of aforementioned arbitrary claim, comprise the fan that is arranged between said outlet and the said heat exchanger, be used to attract air to pass said filter and heat exchanger and filtered air is discharged said outlet.

7. air filter unit according to claim 6, wherein said fan are centrifugal fan.

8. an electric equipment casing comprises outer wall, is equipped with on this outer wall according to the described air filter unit of aforementioned arbitrary claim, and being oriented to of said air filter unit makes said heat exchanger be arranged in said filter top.

9. method of operation according to the described air filter unit of arbitrary claim among the claim 1-7, wherein said air filter unit is attached at the outer wall of casing, and this method comprises:

Attract air to pass said inlet and arrive inside, said unit;

Upwards attract air to pass said filter and heat exchanger from said inlet; And

Air is discharged to the said casing through said outlet from said unit.

10. method according to claim 9; Comprise that condensation is from the airborne steam in the said unit that sucks on the said heat exchanger; To form dewfall, this dewfall falls to pass said air cleaner and pass said inlet from said heat exchanger and drops out outside the said unit.

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