Patent Description:
Compressed air is commonly used in factories to power pneumatic tools and to blow air onto various surfaces for cleaning, expanding bags, moving parts, etc. Typically, factories have a centralized compressed air system installed that feeds a network of compressed air piping that supplies numerous tools or stations with compressed air. Thus, one or more centralized air compressors may be used to supply an entire factory space with compressed air.

However, it is known that air compressors which draw air from the surrounding atmosphere also introduce moisture into the compressed air from the water vapor naturally contained in atmospheric air. Although it is common to use an air dryer in a compressed air system to remove moisture from the compressed air, corrosion can still occur within pipes conveying the compressed air from the compressor to the air dryer. As a result, corroded particles from the compressed air pipes may enter the air dryer and cause damage to the dryer. It is also possible that other foreign particles may be introduced into the compressed air pipes from the compressor or other sources. Thus, it is desirable to filter the compressed air before the air passes through the air dryer. However, with current compressed air filters, it can be difficult to remove and replace the filter element in the air filter. Thus, the inventors believe improved air filters would be desirable.

<CIT> discloses a separating module for a ventilation device, which has a housing that surrounds a separating element designed to separate liquid particles from a gas flow. <CIT>, <CIT> and <CIT> show other relevant documents.

According to the present invention there is provided a filter for compressed air as recited in claim <NUM>.

The invention may be more fully understood by reading the following description in conjunction with the drawings, in which:.

It should be understood that the embodiments shown in <FIG> and <FIG> do not form part of the present invention, but may aid in understanding the invention.

Referring now to the figures, and particularly <FIG>, one embodiment of a compressed air filter <NUM> is shown. In this arrangement, the air inlet <NUM> and the air outlet <NUM> are axially aligned with each other and are parallel to the tubular filter housing <NUM>. The air inlet <NUM> and the air outlet <NUM> are also both connected to the filter housing <NUM>. In use, the air inlet <NUM>, air outlet <NUM> and filter housing <NUM> are preferably oriented horizontally. The filter housing <NUM> is also enclosed by a base <NUM> at one end. The other end of the filter housing <NUM> may be enclosed by an end of the filter housing <NUM> itself. The base <NUM> may be a plate that is bolted to a flange <NUM> of the filter housing <NUM> with threaded screws <NUM>. The filter housing <NUM> and the base <NUM> form an enclosed space <NUM> therein which is capable of containing the compressed air, which typically has a pressure of between <NUM> psi and <NUM> psi but could be as high as <NUM>,<NUM> psi.

One or more filter elements <NUM> are located inside of the enclosed space <NUM> to filter the compressed air as it flows from the air inlet <NUM> to the air outlet <NUM>. That is, the air inlet <NUM> is in communication with one side of the filter elements <NUM>, and the air outlet <NUM> is in communication with the other side of the filter elements <NUM>. As a result, the compressed air must pass through the filter elements <NUM> as it flows from the air inlet <NUM> to the air outlet <NUM>. By passing through the filter elements <NUM>, which include a fine porous structure, foreign particles are trapped within the filter elements <NUM> and prevented from passing to the air outlet <NUM>. Over time, the filter elements <NUM> become clogged with foreign particles and may need to be removed and replaced. As described further below, the filter housing <NUM> and the base <NUM> are removably fastened together to allow the filter housing <NUM> and base <NUM> to be separated in order to remove and replace the filter elements <NUM>.

In the preferred embodiments, the filter elements <NUM> are tubular with an inner diameter and an outer diameter. Even more preferably, the inner diameter (i.e., the first side) is in communication with the air inlet <NUM>, and the outer diameter (i.e., the second side) is in communication with the air outlet <NUM>. Thus, air flows through the filter element <NUM> from the inside of the tubular filter <NUM> to the outside of the filter element <NUM>. In the embodiment of <FIG>, the filter housing <NUM> encloses a plurality of filter elements <NUM> (e.g., five filter elements <NUM>). One end of the filter elements <NUM> may be connected to a divider <NUM> with openings <NUM> aligned with the inner diameters of the filter elements <NUM>. The divider <NUM> prevents air from flowing directly between the air inlet <NUM> and the air outlet <NUM>, and instead, forces the air to flow through the filter elements <NUM> in order to reach the air outlet <NUM>. In this case, air flows through the openings <NUM> in the divider <NUM> to the inside of the filter elements <NUM>. The air then flows through the tubular wall of the respective filter element <NUM> to reach the air outlet <NUM>. The divider <NUM> and filter elements <NUM> may be restrained longitudinally within the filter housing <NUM> with a snap fit or with a longitudinal portion that abuts the base <NUM>.

A valve system may also be provided to allow the filter elements <NUM> to be removed and replaced without shutting down air flow between the air inlet <NUM> and the air outlet <NUM>. For example, a first valve <NUM> may be located between the air inlet <NUM> and the air outlet <NUM>. A second valve <NUM> and a third valve <NUM> may be located, respectively, between the air inlet <NUM> and the filter housing <NUM> and between the air outlet <NUM> and the filter housing <NUM>. In normal operation, the first valve <NUM> will be closed and the second and third valve <NUM>, <NUM> will be opened. This prevents direct flow between the air inlet <NUM> and the air outlet <NUM>, and forces air to flow from the air inlet <NUM> to the filter housing <NUM> and from the filter housing <NUM> to the air outlet <NUM>. However, when it is desired to remove and replace the filter elements <NUM>, the first valve <NUM> may be opened and the second and third valves <NUM>, <NUM> may be closed. This allows unfiltered compressed air to flow directly from the air inlet <NUM> to the air outlet <NUM> and prevents air from flowing to the enclosed space <NUM> in the filter housing <NUM>. The filter elements <NUM> may then be removed and replaced by removing the threaded screws <NUM> and the base plate <NUM> to access the enclosed space <NUM>. Once new filter elements <NUM> have been installed, the base plate <NUM> can be re-fastened and the valves <NUM>, <NUM>, <NUM> changed to normal operation. Thus, the advantage of this arrangement is that it is not necessary to shut off compressed air flow through the system in order to change the filter elements <NUM>.

The embodiment of <FIG> shares numerous features with the previous embodiment, and thus, only additional or different features need to be described for an understanding of <FIG>. In this embodiment of the filter <NUM>, the tubular housing <NUM> is oriented transversely to the air inlet <NUM> and the air outlet <NUM>. In use, the tubular housing <NUM> is preferably oriented vertically, with the air inlet <NUM> and air outlet <NUM> being oriented horizontally. The air inlet <NUM> and the air outlet <NUM> may be axially aligned with each other on opposite sides of the filter housing <NUM>. The base <NUM> may be located at the bottom of the filter housing <NUM>.

The base <NUM> may be connected to the filter housing <NUM> with a hinge <NUM> so that when the threaded screws <NUM> are removed, the base <NUM> rotates away from the filter housing <NUM> to separate therefrom to allow the filter elements <NUM> to be removed and replaced, while still retaining the base <NUM>. The threaded fasteners <NUM> may also be rotatably connected to the filter housing <NUM>, and slotted retainers <NUM> may be provided on the base <NUM> (or vice versa) to allow the threaded screws <NUM> to be loosened and rotated away from the slotted retainers <NUM> to separate the filter housing <NUM> and the base <NUM>.

Like the embodiment of <FIG>, the divider <NUM> may have openings <NUM> which are connected to individual filter elements <NUM> to allow air flow into the center of the tubular filter elements <NUM>. The portion <NUM> of the divider <NUM> with the openings <NUM> is oriented transversely within the filter housing <NUM> with the circular side of the transverse portion <NUM> sealing against the inside of the filter housing <NUM>. The divider <NUM> may also have another portion <NUM> that is oriented longitudinally within the filter housing <NUM>. The sides of the longitudinal portion <NUM> also seal against the inside of the filter housing <NUM>. The longitudinal portion <NUM> is useful to block air flow directly between the air inlet <NUM> and the air outlet <NUM> where the inlet <NUM> and the outlet <NUM> are both connected to the filter housing <NUM> on opposite sides thereof. Also, the longitudinal portion <NUM> may abut against an end of the filter housing <NUM> to position the transverse portion <NUM> and filter elements <NUM> at the desired location.

The embodiment of <FIG> also shares numerous features with the previous embodiments, and thus, only additional or different features need to be described. The compressed air filter <NUM> of <FIG> is shown in relation to an air dryer <NUM> in <FIG>. That is, the filter <NUM> is preferably located in the compressed air system immediately before the air dryer <NUM>, and preferably within the air dryer system housing <NUM>. The air dryer <NUM> may be a conventional air dryer <NUM> which is known in the art to remove moisture from the compressed air. In order to prevent damage to the air dryer <NUM>, the filter <NUM> is located on the inlet side of the air dryer <NUM> to filter the compressed air before it flows through the air dryer <NUM>. It is understood that this same arrangement preferably applies to all of the embodiments herein.

Unlike the previous embodiments, the air inlet <NUM> and the air outlet <NUM> are preferably formed into the base <NUM> in the present embodiment. Also, it is preferable for two filter housings <NUM> to be provided located side-by-side on opposite lateral sides of the air inlet <NUM> and the air outlet <NUM>. Each of the filter housings <NUM> are separately fastened to the base <NUM> (e.g., with a threaded connection <NUM> between each filter housing <NUM> and the base <NUM>) to form two separate enclosed spaces <NUM>. A separate filter element <NUM> is also located in each filter housing <NUM>. In use, the filter housings <NUM> extend downward (that is, transversely) with respect to the air inlet <NUM> and the air outlet <NUM> which are at the top.

Turning to <FIG>, a divider <NUM> may be provided within the tubular section <NUM> defining the air inlet <NUM> and the air outlet <NUM> to prevent direct air flow therebetween. A side opening <NUM> on each opposite side of the air inlet <NUM> allows air to pass to a respective vertical opening <NUM> that is in communication with the interior of the respective filter element <NUM>. Thus, the side openings <NUM> and vertical openings <NUM> form first passages between the air inlet <NUM> and the filter elements <NUM>. After passing through the side wall of the respective filter element <NUM>, the compressed air flows up through the annular space between the outer surface of the filter element <NUM> and the inner surface of the filter housing <NUM>. The air then passes to a vertical opening <NUM> in the annular space <NUM> of the base <NUM>. From there, the air passes through respective side openings <NUM> on opposite sides of the central tubular section <NUM> to the air outlet <NUM>. Thus, the vertical openings <NUM> and side openings <NUM> form second passages between the air outlet <NUM> and the filter elements <NUM>.

Preferably, the base <NUM> is an integral molded component (e.g., a casting) made of metal (e.g., aluminum). Thus, the air inlet <NUM>, air outlet <NUM>, divider <NUM>, first passages <NUM>, <NUM>, and second passages <NUM>, <NUM> are all integrally molded together in a singular, undivided component. In order to allow the side openings <NUM> to be machined after molding, the side openings <NUM> are formed all the way through the base <NUM> from side to side, and threaded plugs <NUM> are fastened into the ends of the side openings <NUM> after machining to close the openings <NUM>. It may also be desirable to provide two pressure sensors <NUM> threaded into the base <NUM>, with one being in communication with the air inlet <NUM> and the other being in communication with the air outlet <NUM> in order to measure the air pressure drop across the filter elements <NUM> and determine when the filter elements <NUM> need to be removed and replaced. Threaded fasteners <NUM> may also be threaded into the top of the base <NUM> in order to mount the filter <NUM> in the air dryer assembly <NUM> and fix the angular position of the filter <NUM>.

Claim 1:
A filter for compressed air, comprising:
an air inlet (<NUM>) and an air outlet (<NUM>);
a filter housing (<NUM>) and a singular base component (<NUM>) enclosing one end of the filter housing (<NUM>), the filter housing (<NUM>) and singular base component (<NUM>) defining an enclosed space (<NUM>) therein;
a filter element (<NUM>) disposed within the enclosed space (<NUM>) of the filter housing (<NUM>) and the singular base component (<NUM>);
wherein the air inlet (<NUM>) is in communication with a first side of the filter element (<NUM>) and the air outlet (<NUM>) is in communication with a second side of the filter element such that air flow from the air inlet to the air outlet passes through the filter element;
wherein the singular base component (<NUM>) and the filter housing (<NUM>) are removably fastened together such that the singular base component (<NUM>) and the filter housing (<NUM>) may be separated from each other to permit the filter element (<NUM>) to be removed and replaced;
wherein the filter further comprises at least two of the filter housings (<NUM>), each of the filter housings (<NUM>) being removably fastened to the singular base component (<NUM>) and defining separate ones of the enclosed space (<NUM>);
wherein at least one of the filter elements (<NUM>) is disposed within each enclosed space (<NUM>);
wherein the singular base component (<NUM>) comprises a divider (<NUM>) between the air inlet (<NUM>) and the air outlet (<NUM>) to prevent direct flow therebetween, first passages between the air inlet (<NUM>) and each of the first sides of the filter elements (<NUM>), and second passages between the air outlet (<NUM>) and each of the second sides of the filter elements; and
wherein the air inlet (<NUM>), the air outlet (<NUM>), the divider (<NUM>), the first passages and the second passages are integrally molded into the singular base component (<NUM>).