ARRANGEMENT AND METHOD FOR FORMING A FOCUSED CLEAN AIR ZONE COLUMN

[0001] The present application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/370,683, filed on Aug. 4, 2010, which is incorporated herein by reference in its entirety.

[0002] There are many circumstances where it is absolutely essential to assure a clean or sterile environment. An obvious example is in hospitals, and especially in operating rooms of hospitals. In the operating room setting, it is the wound site of the patient where sterility is of most importance. Unfortunately, in current approaches, the most critical area of concern, the wound site, is not given primary attention. Rather, current approaches have been just the opposite by giving attention to the condition of the operating room in general in creating a “clean” room without paying special attention to the wound site. This can result in the wound site actually being the area of least cleanliness because it is at the wound site that the most activity occurs during a surgical procedure that both sets contaminants airborne and blocks clean air access to the wound site.

[0003] Contaminated particles can be made up of particulates from any substance, such as dirt and dust, and can include bacterial and virus nebular matter transported either through the air from multiple sources or by touch on surfaces. Neither source of transport can be ignored. The same contaminates can pass from air to surface many times over the course of existence. The present invention addresses the need for establishing a clean air environment at a targeted site, such as, for example, a surgically sterile wound site of a patient.

[0004] In one embodiment the invention provides an arrangement for establishing a focused clean air zone column comprising an ultra-high grade filter having an air intake and an air flow generator that forces air from the intake through the filter. The air flow generator is operable to force air from the filter at a velocity between 70 feet per minute to 200 feet per minute to form a focused clean air zone column of air extending from the filter.

[0005] The air flow generator may be a blower. The blower may be an impeller blower.

[0006] The ultra-high grade filter may be a HEPA filter or a ULPA filter, for example. The filter may be ceiling or wall mountable. To that end, the filter may be dimensioned to fit within T-bar ceiling supports.

[0007] The arrangement may further comprise a shroud extending from the filter in the direction of air flow from the filter unit to displace the focused clean air zone column. The filter has a perimeter defining a shape and a dimension and the shroud defines a shape and a dimension corresponding to the shape and dimension of the filter perimeter.

[0008] In another embodiment, the invention provides a method of establishing a focused clean air zone column. The method includes the steps of comprising providing a filter including a high grade filter and an air intake and forcing air from the filter at a velocity between 70 feet per minute to 200 feet per minute to form a focused clean air zone column of air extending from the filter.

[0009] In another embodiment, the invention provides an arrangement for establishing a surgical quality clean air environment at a target site. The arrangement comprises a filter unit including an ultra-high grade filter, an air intake and an air flow generator that forces air from the intake through the filter. The air flow generator is operable to force air from the filter at a velocity between 70 feet per minute to 200 feet per minute to form a focused clean air zone column of air extending from the filter. The arrangement further includes a support that places the target site within the focused clean air zone column.

[0010] The air flow generator may a blower. The blower may be an impeller blower.

[0011] The ultra-high grade filter may be a HEPA filter or a ULPA filter, for example. The filter unit may be ceiling or wall mountable. To that end, the filter unit may be dimensioned to fit within T-bar ceiling supports.

[0012] The arrangement may further comprise a shroud extending from the filter unit in the direction of air flow from the filter unit to displace the focused clean air zone column. The filter has a perimeter defining a shape and a dimension and the shroud defines a shape and a dimension corresponding to the shape and dimension of the filter perimeter.

[0013] In another embodiment, the invention provides a method of establishing a focused clean air zone column. The method includes the steps of comprising providing a filter including a high grade filter and an air intake and forcing air from the filter at a velocity between 70 feet per minute to 200 feet per minute to form a focused clean air zone column of air extending from the filter.

[0014] In a still further embodiment, the invention provides a method of establishing a surgical quality clean air environment at a target site. The method includes providing a filter unit including an ultra-high grade filter and an air intake, forcing air from the filter at a velocity between 70 feet per minute to 200 feet per minute to form a focused clean air zone column of air extending from the filter, and directing the focused clean air zone column onto the target site.

[0025] Referring now to FIG. 1, it shows an operating room 20 having a ceiling 22 and a floor 24. Also shown is a patient 26 in need of a surgical procedure disposed in a supine position on an operating table 28.

[0026] Above the patient and mounted within the ceiling 22 is a ceiling mounted filter unit 30 embodying the present invention. The filter unit includes an ultra-high grade filter 32 and a blower 34. Air enters the filter unit 30 through an intake 36.

[0027] The ultra-grade filter may be a high efficiency particle arrestor (HEPA) filter, an ultimate level particle arrester (ULPA) filter, or any other filter having filter characteristics the same as or better than a HEPA filter efficiency grade. HEPA filters are 99.99 percent or greater efficient for particles at 0.3 microns in size and larger. ULPA filters are 99.999 percent or greater efficient for particles at 0.1 microns in size and larger.

[0028] The air provided to intake 36 may be from the building regular air supply directly or indirectly connected. Alternatively, the air supplied to intake 36 may to some degree be pre-filtered.

[0029] The blower 34 forms an air flow generator that pulls air from the intake 36 and forces the air through the filter 32. It may be an impeller blower, for example. Alternatively the blower may be an axial blower or a housed blower.

[0030] In accordance with the present invention, the blower is operable to force air 37 from the filter face 38 at a velocity between 70 feet per minute to 200 feet per minute. The ultra-clean air exiting the filter 32 within that velocity range will form a focused clean air zone column 40 extending from the filter face 38. The focused clean air zone column 40 has a profile comprising a plurality of zones 42, 44, 46, and 48. Each zone represents a minimum number of airborne particles per cubic foot of air. The profile of the focused clean air zone column will be described more completely subsequently.

[0031] The operating table 28 is arranged to place the patient 26 into a position whereby the critical surgical wound site of the patient 26 will be within zone 48 of the focused clean air zone column 40. This assures that the surgical wound site will be within surgically clean air.

[0032] The focused clean air column 40 commences at the point the airflow projection expels into a surrounding air from the rigid enclosure and filter. Here, the focused clean air column 40 commences at the filter exhaust side face 38. The air flows as a nearly single mass with the air across the column flowing at nearly the same velocity, thereby creating laminar flow. The air that is constantly being expelled is pushing the air mass in front until all of the energy is expended.

[0033] FIG. 2 shows the profile of the focused clean air zone column 40 of FIG. 1 for an initial air flow velocity at the filter face 38 of 90 feet per minute. As the air flows out from the filter, air outside of the column 40 will begin to mix with the air within the column along the corresponding edges 40. However, by virtue of the laminar flow of the air and the initial cleanliness of the air at the filter face 38, the air within the column 40 remains extremely clean throughout the length of the column 40. To that end, the first zone 42 extends out to about 1.5 feet and contains less than 100 particles per cubic foot of air. The second zone 44 extends out to about 2.5 feet and contains less than 150 particles per cubic foot of air. The third zone 46 extends out to about just over 4 feet and contains less than 200 particles per cubic foot of air. Lastly, the fourth zone 46 extends out to over 6 feet and contains less than 300 particles per cubic foot of air. As shown in FIG. 1, the patient is disposed within the fourth zone 48. Any one of these zones would provide sufficiently clean air to support a surgical procedure within a surgically clean air environment at the serial field target.

[0034] FIG. 2 also shows the air velocity for air flow out from the filter 32. At 4 feet out, for example, the air flow velocity is about 50 feet per minute. It is important that the air velocity not be so high as to cause rapid drying of tissue at the surgical wound site or create turbulence within the zone thereby reducing its effectiveness. All of the air velocities shown in FIG. 2 are well below such an air velocity. However, all of the air flow velocities illustrated are sufficient to provide an additional important function. That is to force any contaminants 54 (FIG. 1) created during the surgery and other undesirable airborne side products from the surgery, such as cauterization smoke, to be forced downward gently towards the floor and away and down below the surgical wound site and the operating room personnel upper portion of their bodies without any bounce back of the contaminated smoke filled air into critical areas off nearby objects or the floor.

[0035] Referring now to FIG. 3, it shows another operating room 120 having a focused clean air zone column 140 extending therein formed by an initial air velocity of 120 feet per minute. The operating room 120 has a ceiling 122 and a floor 124. Also shown is a patient 126 in need of a surgical procedure disposed in a supine position on an operating table 128.

[0036] Above the patient and mounted within the ceiling 122 is a ceiling mounted filter unit 130 embodying the present invention. The filter unit includes an ultra-high grade filter 132 and a blower 134. Air enters the filter unit 130 through an intake 136.

[0037] As in the previous embodiment, the ultra-grade filter may be a high efficiency particle arrestor (HEPA) filter, an ultimate level particle arrester (ULPA) filter, or any other filter having filter characteristics the same as or better than a HEPA filter. HEPA filters are 99.99 percent efficient for particles at 0.3 microns in size or larger.

[0038] The air provided to intake 136 may be from the building regular air supply. Alternatively, the air supplied to intake 136 may to some degree be pre-filtered.

[0039] The blower 134 forms an air flow generator. As in the previous embodiment, it may be an impeller blower, for example. Alternatively the blower may be an axial blower or a housed blower.

[0040] In accordance with this embodiment of the present invention, the blower is operable to force air 137 from the filter face 138 at a velocity of 120 feet per minute, within the 70 feet per minute to 200 feet per minute velocity range previously mentioned. The ultra-clean air exiting the filter 132 at those velocities will thus form the focused clean air zone column 140 extending from the filter face 138. The focused clean air zone column 140 has a profile comprising a plurality of zones 142, 144, 146, and 148. Again, each zone represents a minimum number of airborne particles per cubic foot of air.

[0041] The operating table 128 is arranged to place the patient 126 into a position whereby the surgical wound site of the patient 126 will be within zone 146 of the focused clean air zone column 140. This assures that the surgical wound site will be within surgical quality clean air.

[0042] The focused clean air zone column 140 commences at the filter face 38. Because the initial flow velocity is within the 70 to 200 foot per minute velocity range, the air flows as a nearly single mass with the air across the column flowing at nearly uniform velocity in laminar flow.

[0043] FIG. 4 shows the profile of the focused clean air zone column 140 of FIG. 3. As the air flows out from the filter, air outside of the column 140 will begin to mix with the air within the column 140. However, by virtue of the laminar flow of the air and the initial cleanliness of the air at the filter face 138, the air within the column 140 remains extremely clean throughout the length of the column 140. To that end, the first zone 142 extends out to just over 2 feet and contains less than 100 particles per cubic foot of air. The second zone 144 extends out to just over 3.5 feet and contains less than 150 particles per cubic foot of air. The third zone 146 extends out to about just over 5.5 feet and contains less than 200 particles per cubic foot of air. Lastly, the fourth zone 148 extends out to over 7 feet and contains less than 300 particles per cubic foot of air. Any one of these zones would provide sufficiently clean air to support a surgical procedure within a surgically clean air environment. As may be realized from the profile of FIG. 2 representing an initial air flow velocity of 90 feet per minute and the profile of FIG. 4 representing an initial air flow velocity 120 feet per minute, the focused clean air zone columns are similar except that the column formed with an initial velocity of 120 feet per minute extends out farther than the column formed with an initial velocity of 90 feet per minute.

[0044] FIG. 4 also shows the air velocity for air flow out from the filter 132. While the air flow velocities represented in the profile of FIG. 4 are higher than in the profile of FIG. 2, the air flow velocities shown in FIG. 4 are still not so high as to cause rapid drying of tissue at the surgical open wound site. All of the air velocities shown in FIG. 4 are well below such an air velocity.

[0045] FIG. 5 is a partial perspective view of a ceiling 222 having a filter unit 230 mounted within the T-bar supports of the ceiling. In the arrangement of FIG. 5, intake air may most readily be obtained from the building HVAC system. However, the intake air may be obtained from other sources as well and may even be pre-filtered to some extent. While hospitals and hospital operating rooms would not generally use T-bar ceiling supports, such a ceiling is shown herein to emphasize the point that a surgically clean air targeted air environment may be obtain in most any room or space by practicing the embodiments of the invention.

[0046] FIG. 6 is a side view of the filter unit 232 embodying aspects of the present invention which may be mounted within the ceiling of FIG. 5 or used in most any application according to the invention, including within hospitals and operating rooms. The filter unit includes a filter housing 231 and a blower housing 233. The filter housing contains an ultra-high grade filter (not shown) and the blower housing 233 contains an impeller blower 234. Air enters the filter unit 230 through an intake 236. The interior 235 of the blower housing 233 forms a plenum chamber which, along with the back pressure provided by the ultra-high grade filter, causes the air flow 237 from the blower 234 to be evenly distributed across the filter face 238. The blower 234 is operable to force the air through the filter at initial air flow velocities from 70 feet per minute to 200 feet per minute. This causes a focused clean air zone column 240 of air to extend form the filter face 238.

[0047] FIG. 7 is a side view of the filter unit 230 of FIG. 6 but further including a shroud 252 to displace the focused clean air zone column according to further aspects of the invention. In some applications, it may be necessary to displace the focused clean air zone column to accommodate very high ceilings or other obstacles to placing the target area within the focused clean air zone column. The shroud may be employed to confine the air before it is released to free space. To that end the shroud has a length L and a perimeter that matches the perimeter of the filter face 238. By matching the perimeter (shape and dimension) of the filter face 238, it is assured that there will be no leakage of area from the shroud. When the laminar air flow exits the shroud, the focused clean air zone column profile will be displaced in the direction of air flow 237 by a distance L equal to the length of the shroud. The shroud may be formed of any material which provides a barrier between the air within the shroud and the surrounding contaminated air. Hence, the shroud may be formed of plastic, metal, or even cloth.

[0048] FIG. 8 is a simplified view of an operating room with a patient on an operating table and placed within a focused clean air zone column displaced by the shroud of FIG. 7 according to further aspects of the present invention. The arrangement of FIG. 8 is based upon an initial air flow velocity to form the focused clean air zone column of 90 feet per minute. This allows the arrangement of FIG. 8 to be directly compared to the arrangement of FIG. 1. In FIG. 1, the patient was disposed within the fourth zone 248. However, by virtue of the shroud 252 extending from the filter face 238, the focused clean air zone has been displaced in FIG. 8 so that the patient is now disposed within the third zone 246. As a result, the surgical wound site of the patient 226 of FIG. 8 will now be in a cleaner level air zone than the surgical wound site of the patient 26 of FIG. 1.

[0049] FIG. 9 is a side view of a mobile or portable unit capable of providing a focused clean air zone column according to still further aspects of the invention. The unit 300 of FIG. 9 includes a base 310 that may be rolled about in casters 312 over a floor 302. The unit 300 further includes a column 314 extending from the base 310. The column includes an air intake 336 which communicates with a blower chamber 334. The blower chamber may include an impeller blower, for example. The blower forces air from intake 336 up the column 314 though a flexible join 316 to a filter housing 318. Within the filter housing 318 is an ultra-high grade filter having a filter face 338. In accordance with this embodiment of the invention, the blower within blower chamber 334 is capable of pulling air from the intake and pushing out the filter face at a velocity between 70 and 200 feet per minute. As may be seen in FIG. 9, this establishes a focused clean air zone column 340—that may be aimed by the flexible joint 316 onto a target area of interest. Hence, as may be seen from the foregoing, the invention is not limited to stationary implementation but may be employed to advantage in portable implementations as well.

[0050] While particular embodiments of the present invention have been shown and described, modifications may be made, and it is therefore intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the invention as defined by those claims.