Patent Application
20170144096
The present invention relates to vacuum filters. More specifically, the present invention relates to an improved vacuum filter which may be used to collect materials which may contain hot materials such as sparks or ash.
It is often desirable to use a vacuum to collect debris which may contain hot materials. For example, it is often convenient to use a vacuum to collect ash from fireplace. Many existing vacuum filters are not suitable for this use. It is desirable to have a vacuum bag which is better suited for collecting debris which may contain hot materials.
Non-limiting and non-exhaustive examples of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.
Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of various examples of the present invention. Also, common but well-understood elements that are useful or necessary in a commercially feasible embodiment are often not depicted in order to facilitate a less obstructed view of these various embodiments of the present invention.
It will be appreciated that the drawings are illustrative and not limiting of the scope of the invention which is defined by the appended claims. The examples shown each accomplish various different advantages. It is appreciated that it is not possible to clearly show each element or advantage in a single figure, and as such, multiple figures are presented to separately illustrate the various details of the examples in greater clarity. Similarly, not every example need accomplish all advantages of the present disclosure.
In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one having ordinary skill in the art that the specific detail need not be employed to practice the present invention. In other instances, well-known materials or methods have not been described in detail in order to avoid obscuring the present invention.
Reference throughout this specification to “one embodiment”, “an embodiment”, “one example” or “an example” means that a particular feature, structure or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment”, “in an embodiment”, “one example” or “an example” in various places throughout this specification are not necessarily all referring to the same embodiment or example. Furthermore, the particular features, structures or characteristics may be combined in any suitable combination and/or sub-combinations in one or more embodiments or examples. In addition, it is appreciated that the figures provided herewith are for explanation purposes to persons ordinarily skilled in the art and that the drawings are not necessarily drawn to scale.
The disclosure particularly describes a vacuum filter which is more resistant to hot materials. Particularly, the present disclosure describes a vacuum filter which is more resistant to damage from contact with hot materials and which will continue to function as a filter and to protect the vacuum motor from damage when the filter has been damaged by hot materials.
Vacuums are commonly used to collect debris. Portable canister vacuums, or shop vacuums, are increasingly common. Referring to
These vacuums are often used to collect debris which may damage the filter 34. As mentioned, canister vacuums are often used to clean ash from a fireplace. Even though the ash is collected after the fire is dead and the ash has cooled, it is not uncommon to find small pieces of hot ash or hot embers in the fireplace ash. The ash is quite insulating and allows an ember to maintain a high temperature for a long period of time. The ash also impedes contact between an ember and air and slows the burning of the ember. As a result, fireplace ash may contain hot embers days after the last fire. Particularly in cold seasons, a user may not be able to wait sufficiently long after a fire for the ash to completely cool because they may need to light another fire to heat their home.
The filter 34 has been designed to provide additional resistance to damage from hot sparks, ash, embers, etc. The filter 34 has also been designed to still provide filtration after the filter has been damaged so that the vacuum motor 22 and fan 26 are protected from damage and so that dust is not ejected from the vacuum. While the filter 34 may need to be replaced after contact with a quantity of hot material, the vacuum itself and the surrounding environment are protected from the effects of filter failure.
Turning now to
The core layer 66 is preferably made of fiberglass. By way of example, the core layer 66 may be made of a woven fiberglass cloth which is between about 0.02 and about 0.06 inches thick, and is preferably about 0.04 inches thick. The core layer 66 may be made of a fiberglass cloth or woven roving type cloth which is between 10 and 40 ounces per square yard, preferably between 18 and 30 ounces per square yard, and more preferably about 24 ounces per square yard. Typical 24 ounce per square yard fiberglass cloth has a thickness which is about 0.04 inches. The woven fiberglass core 66 is sufficiently tightly woven that there are not any significant openings or holes through the fiberglass. The woven fiberglass allows air flow and does not pose significant restriction to air flow, but will not allow large pieces of debris to pass through the fiberglass.
The filter 34 is assembled so that the outside surface of the filter (i.e. the side of the filter which is exposed to incoming ‘outside’ air and debris) is the fire resistant coating material 74 and the polyester filter material 62 to which the coating is attached. The core 66 is disposed against the outer layer 62 of filter material, and the inner layer 70 of filter material is disposed against the core 66. In some embodiments, it may not be necessary to use a fire resistant coating material on the inner layer 70 of filter material.
In use, dirty air and debris flow through the outer layer 62 of filter material (and fire resistant coating 74) and the outer layer 62 of filter material removes the debris which is entrained in the air. The cleaned air then flows through the woven fiberglass core 66 and through the inner layer 70 of filter material. In the sense of filtration, the inner layer 70 of filter media is redundant as the outer layer 62 of filter media removes the debris from the air. This is particularly true where the outer layer 62 and inner layer 70 of filter media are made from the same type of filter media. In the present example, the outer layer 62 and inner layer 70 of filter media are both made from a spun bonded polyester media which is approximately 0.06 inches thick. Preferably, the outer layer 62 and inner layer 70 are made with a filter material having sufficiently fine pores to collect the majority of fine particulates, such as when a person is vacuuming ash, sheetrock dust, fine dirt, etc. The vacuum bags may be made with a fine enough filter material to be HEPA rated in collecting fine particulates. For example, the filter material used for the outer layer 62 and inner layer 70 may retain particles with sizes down to about 0.5 micron. In an example filter, the downstream layer 70 of filter material has approximately the same filtration efficiency or pore size as the upstream layer 62 of filter material and thus does not capture significant amounts of debris while the upstream layer 62 of filter material is intact and functioning.
The core 66 of woven fiberglass provides a barrier against hot materials such as hot ash, embers, and sparks should the outer layer 62 of filter material fail. As an example, it is not uncommon when vacuuming ash from a fireplace to draw live embers into the vacuum. These hot embers will gradually damage the outer layer 62 of filter material. The air flow through the vacuum filter 34 will often hold embers or the like against the filter 34 and cause the hot ember to melt or burn a hole through the outer layer 62 of filter material. The fiberglass core 66, while not providing a significant amount of filtration, provides structural support to the filter 34 in the event that the outer layer 62 of filter material is damaged. Moreover, the core 66 is highly resistant to hot materials such as embers and will keep the ember from burning through the filter 34. The core 66 protects the inner layer 70 of filter material from the hot debris. Once a hole is melted through the outer layer 62 of filter material, unfiltered air passes through the hole in the outer layer 62 of filter material and passes through the core 66. The core 66 will stop large debris and protects the inner layer 70 of filter material from any hot debris such as embers. The inner layer 70 of filter material then begins filtering the remaining fine debris from the airstream.
As such, the inner layer 70 of filter material and the core 66 do not significantly participate in the filtration until the outer layer 62 of filter material is damaged. At this point, the core 66 becomes active in protecting the inner layer 70 of filter material and the inner layer 70 of filter material becomes active in filtering the dust from the air stream. Until the outer layer 62 of filter material is damaged, dust and debris is deposited on the outside surface of the filter 34 where is can be removed from the filter. Once the outer layer 62 of the filter material is damaged and breached, dust will deposit on the core 66 and inner layer 70 of the filter material where it is not easily cleaned. This dust and debris, however, is prevented from flowing through the impeller 26 and motor 22.
The filter 34 will thus protect the vacuum motor 22 and impeller 26 from damage even after the outer layer 62 of filter material is damaged. The core 66 and inner layer 70 of filter material will typically provide adequate filtration of the air stream until the vacuum canister needs emptying or the filter 34 needs cleaning. At this point, the user will be able to visually identify the damage to the outer layer 62 of filter material and can replace the filter 34.
The undamaged filter 34 is readily cleanable and reusable because the dust and debris is primarily deposited on the outer surface of the filter 34. The filter 34 can thus be shaken or blown off and reused. The filter 34 may be reused until damaged and thus provides an extended service life. Once damaged, the core 66 and inner layer 70 of filter material provide continuing filtration to protect the impeller 26 and motor 22 and prevent damage to the vacuum until the damaged outer layer 62 of filter material is discovered and the filter 34 is replaced.
The above description of illustrated examples of the present invention, including what is described in the Abstract, are not intended to be exhaustive or to be limitation to the precise forms disclosed. While specific examples of the invention are described herein for illustrative purposes, various equivalent modifications are possible without departing from the broader scope of the present claims. Indeed, it is appreciated that specific example dimensions, materials, etc., are provided for explanation purposes and that other values may also be employed in other examples in accordance with the teachings of the present invention.
