Patent Application
20220061971
The present invention generally relates to a ventilation unit. More particularly, the present invention relates to a dental ventilation unit with an improved air intake and fan mount assembly.
Transmission of communicable diseases can be a concern in a dental operatory, especially the transmission of SARS-CoV-2, which may result in COVID-19. SARS-CoV-2 is transmissible in at least two ways in a dental operatory. First, it may be transmitted during procedures utilizing high speed handpieces and ultrasonics through the generation of aerosols. Theses aerosols consist of mainly water and saliva. Virus particles shed from the upper respiratory tract may be attached to droplets of water and saliva which are then expelled as aerosols through air forced out of the conventional air driven handpiece. The SARS-CoV-2 virus may then be inhaled into the upper respiratory tract by the dental staff and infect them.
In addition, SARS-CoV-2 may also be transmitted in non-aerosol generating procedures. Research has shown that prolonged exposure to a virus carrier in a poorly ventilated area is likely to lead to contracting SARS-CoV-2. This may occur as a result of what is known as airborne transmission. As respiratory droplets are expelled through normal speaking and breathing the water content begins to evaporate, resulting in an extremely light particle with attached virus particles that may be able to remain aloft for a considerably long period. Recent scientific studies were unable to find a biologic half-life of the SARS-CoV-2 artificially suspended in a rotating drum at 16 hours, which was the extent of the allotted experimental time. As a result, the virus may be transmitted from patient to patient, or patient to staff by inhaling virus particles that were generated from previous appointments and remain aloft in the dental operatory. Due to the hardiness of the SARS-CoV-2 virus, airborne suspended virus particles from a morning patient may potentially be transmitted to anyone having a subsequent appointment in the same room.
One or more of the embodiments of the present invention provide a dental ventilation system and method. The dental ventilation system includes an improved fan mount assembly and several embodiments of an air intake. The fan mount assembly receives a fan unit having a perimeter ring in a fan unit aperture so that the perimeter ring is positioned on top of and supported by the top surface of the fan mount assembly. A locking ring is then positioned over the perimeter ring and bolts are passed through bolt holes in the locking ring and fan mount assembly to secure the fan unit and locking ring to the fan mount assembly. A duct hose connects the fan mount assembly to an air intake and several embodiments of the air intake are provided. In one embodiment, the air intake includes a light receptacle positioning a removable light to illuminate a patient and a battery holder holding a removable battery that is electrically connected to and powers the removable light. The air intake also includes a plurality of barbs that engage the air intake with the duct hose.
One or more embodiments of the present dental ventilation system and method were designed with the intent of disease control. Specifically the present dental ventilation system is designed to reduce the transmission of SARS-CoV-2 in the dental operatory.
One or more embodiments of the present ventilation system are designed to provide an air intake as close as possible to the patient in order to evacuate aerosols generated by the patient to the outdoors where the aerosols are diluted or passed through a HEPA (High Efficiency Particulate Air) filter and subsequently into the return plenum of the HVAC (Heating, Ventilation and Air Conditioning) system.
As further described below, the air intake 1010 may be configured with a bellmouth design and may include handles and lights positioned to illuminate the patient, for example for operation. The filter box 1040 may include a HEPA filter and/or ultraviolet (UV) sanitation system. Additionally, as further described below, the inline fan 1060 may employ a clamshell mount that may provide additional stability and as tight an air-tight connection as possible. The fan output conduit 1080 may vent to a roof vent or an return plenum, for example with a HEPA filter. The pressure gauge 1-9—may be a magnahelic differential pressure gauge, for example if negative pressure in the operatory 1005 is desired.
In operation, the present ventilation system reduces the incidence of aerosols in the dental operatory by providing what is referred to as air changes per hour. Basically, air change is described as the time it takes to remove a room's entire volume of air. One or more embodiments of the present system are engineered to provide at least twelve air changes per hour per the ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) specifications for an airborne isolation room in a typical dental operatory. The typical dental operatory consists of approximately 1000 cubic feet. In one embodiment, the present system is designed to flow at least 200 cubic feet a minute, but can be adjusted to flow more or less based on the room size to a maximum of 1000 cubic feet per minute. At 200 cubic feet a minute, a typical 1000 cubic feet room will undergo an air change in 5 minutes, resulting in the isolation room specification of twelve air changes an hour. At this air exchange rate the CDC (Center for Disease Control) states the room to be 99% free of airborne contaminants in 23 minutes and 99.9% free in 35 minutes. This, the present system provides a safe environment in 30 minutes for subsequent patients and staff.
In regards to the airflow, in one embodiment the fans have a rheostat to control the speed, which may be controlled by a small dial in the wall like a light dimmer. One specific embodiment is the WC15 from Fantech. In one embodiment, the amount of air flowed may be dependent on the makeup air system, which preferably provides at least 200 cfm (cubic feet per minute) to be effective at aerosol removal, but may flow more to increase aerosol removal. Air removed from the operatory is replaced by the makeup air system to maintain proper building pressurization. The fan speed may be set using the rheostat by the mechanical contractor based on room size, desired air flow (at least 200 cfm), and make up air system.
In one embodiment, the present system is designed to utilize a sealed inline fan motor. This type of motor is less expensive and much quieter than the typical vacuum blower type motors. The prototype unit was built using the Fantech fg6x1 unit. In order for the fan to function properly six inch duct was chosen to keep the static pressure exerted on the fan within the manufacturer's specifications. However, different fans may be utilized and ductwork of other specifications may be utilized depending on the fan.
The exhaust portion of the system may include anything downstream of the fan. In a direct exhaust application the fan is connected to a roof duct directly with a flexible duct section secured on each end with a metal band type clamp typical of ductwork.
When direct exhaust system is not possible due to climate and make up air requirements the system may be connected to the return plenum of the HVAC system. Such an application will use the placement of a filter system between the intake duct and fan unit. Currently HEPA type filters are currently used to filter the 0.125 micron Sars-Cov-2 virus. HEPA filters were originally designed to filter radioactive dust and do a great job of filtering particles in 0.1-0.3 micron range.
In operation, the fan mount assembly 100 a fan ring 110 that rests on the upper surface of a fan mount 115. The fan mount 115 is shown in
In operation, once the fan unit 105 has been positioned in the fan mount 115 to that the fan ring 110 is resting on the top surface of the fan mount 115, the locking ring 120 is placed over the fan ring 110. In this position, the power box 125 is located in the fan mount power box keyhole aperture 140 and the locking ring power box keyhole aperture 165. Additionally, the locking ring bolt holes 160 and fan mount bolt holes 150 are aligned so that a bolt may be passed vertically through each of the aligned bolt holes in order to clamp the locking ring 120 to the fan mount 115 thereby fixing the fan unit 105 in place in the fan mount 115.
In another embodiment, to promote the air seal integrity of the Fantech fan unit a clamshell type mount is employed, as further described below. In this embodiment, the fan unit has a small ring or lip resulting from the joining and clamping of the two halves, upper and lower, of the galvanized steel fan housing. The fan is placed in the clamshell fan mount and rests on the ring. Then the securing piece with aligning geometry is placed over the fan housing on top of the ring on the fan. The securing piece is hinged at one end, allowing the securing piece to rotate up and down like a clamshell.
The securing piece is then bolted to the lower fan mount, which clamps the fan in place. The clamping mount is used in order to maintain the air sealed quality of the fan unit by eliminating the use of sheet metal screws placed into the housing in the typical mounting fashion. The clamping mount is mounted above the operatory. The fan has a lower intake ring designed to accommodate the appropriate size duct. In this application it is a 6″ duct.
As shown in
In operation, to assemble the fan mount 115, the first side flap 320 is bent along the first side flap fold line 321 so that the first side flap 320 is perpendicular to the main fan mount section 305. Similarly, the second side flap 325 is bent along the second side flap fold line 326 so that the second side flap 325 is perpendicular to the main fan mount section 305. Next, the first side flap rear segment 341 is bent along the first side flap bottom fold line 323 so that the first side flap rear segment 341 is perpendicular to the first side flap 320. Similarly, the second side flap rear segment 342 is bent along the second side flap bottom fold line 328 so that the second side flap rear segment 342 is perpendicular to the second side flap 325. Next, the rear flap 310 is bent along the rear flap fold line 311 so that the rear flap 310 is perpendicular to the main fan mount section 305. By bending the rear flap 310 into this configuration, the first side flap mounting holes 322 align with the first side rear flap mounting holes 324 and the second side flap mounting holes 327 align with the second side rear flap mounting holes 329.
As shown in
In operation the aligned first side flap mounting holes 322, first side rear flap mounting holes 324, second side flap mounting holes 327, and second side rear flap mounting holes 329 form the plurality of structural element mounting holes 145 shown in
Alternatively,
A self-supporting pliable duct material, for example that known by the brand name Pliaduct, may extend into the operatory. The duct fully when extended terminates roughly 6″ from the oral cavity of a reclined patient. The pliable duct material allows the intake to be adjusted by an operator in 3 dimensions to any desired position to accommodate the patient's position and the line of vision needs of the dentist while positioning the intake as close as possible to the oral workspace in order to collect the maximum of aerosols generated. The pliable duct maintains the intake position after each adjustment due to its internal rigid structure, which is rigid enough to support the weight of the duct as well as the intake to the duct.
In addition, the pliable duct allows the intake be positioned above the patient when sitting to collect virus particles shed in normal breathing and speaking. It also allows the patient to be reclined without interference from the intake position. In one embodiment, the intake may be an aerodynamic shape such as a Bellmouth, as are used in turbine engine intakes. The intake may alternatively take various forms such as rectangular or ovoid.
As further shown and describe below, the outer surface of the intake slides into the inner portion of the duct. Small tabs on the intake engage slots prepared in the duct in order to connect the intake to the duct and to preventing the intake from slipping out of the duct and contacting the patient. In addition, small bolts or screws may be placed through the material of the duct and intake preventing the intake from sliding off. The intake and duct may alternatively or in addition be secured together in a friction arrangement with a metal band clamp and worm gear typical for ductwork. The intake may also have provisions for handles and the placement of a small spot type LED (Light-Emitting Diode) light for vision when the chair light is blocked by the intake.
In one embodiment, the light is mounted on the edge of the intake. The positioning and direction of the light may be adjustable independent from the intake. The beam width may vary between 4 and 20 degrees. The color of the light is preferably between 5000-7000 kelvin.
The alternative embodiment of the air intake 1100 of
In operation, a generally cylindrical light is introduced into the light receptacle 1120 and slides downward into the light receptacle until the lowest edge of the light contacts the circular stop structure 1310. The light is electrically connected to a battery that is placed in the battery holder 1130 in order to power the light. The light may then be activated or deactivated by an operator so that light is emitted downward from the light receptacle and illuminates the patient.
In one embodiment, the present invention bridges the gap between mechanical contractor and dentist. The present dental ventilation system has been dentist designed, tested, and streamlined for quick installation. All kits are tested with a NIST (National Institute of Standards and Technology)-calibrated air velocity probe prior to shipping, reducing time required to balance the system. It typically takes a single mechanical contractor one day per operatory, yielding a cost of $800-1500 per unit for installation.
One or more embodiments of the present dental ventilation system may provide everything required to turn any closed door dentist operatory into a negative pressure isolation room with direct outdoor exhaust and may also provide excellent particle capture and ventilation for open operatories. The present dental ventilation system has the airflow capacity for an isolation room and the capture velocity necessary for extra-oral particle vacuum. One or more embodiments of the present dental ventilation system includes an extra-oral suction intake with light, flexible intake duct hose that holds its position, commercial exhaust fan, stainless steel attic mounts, roof vent, ceiling trim ring, and all hardware.
Additionally, one or more embodiments of the present dental ventilation system may include a make up air system to keep proper building pressurization. The make up air system includes a filter for incoming air, lighted intake, flexible intake hose, commercial fan, ceiling trim ring, and stainless steel attic mounts and may be pre-calibrated with a NIST certified probe. Additionally, an inline duct heater or dehumidifier can be added depending on climate and current HVAC system.
One or more embodiments of the present dental ventilation system may also include HEPA filter units which may be identical to the direct exhaust units with the addition of a high quality inline HEPA filter unit. Preferable, only medical grade DOP (Dispersed Oil Particulate) tested HEPA filters are employed. In addition, the filter housing may include gauges indicating the filter health and may include attic mounting hardware with ducts routing the floor in the most distant corner for particle settling.
One or more embodiments of the present ventilation system may alternatively be used in more general surgical environment such as a hospital or doctor's office. Additionally, one or more embodiments of the present ventilation system may be employed in other settings such as a restaurant.
While particular elements, embodiments, and applications of the present invention have been shown and described, it is understood that the invention is not limited thereto because modifications may be made by those skilled in the art, particularly in light of the foregoing teaching. It is therefore contemplated by the appended claims to cover such modifications and incorporate those features which come within the spirit and scope of the invention.
The present application claims the benefit of U.S. Provisional Application No. 63/073,498, filed Sep. 2, 2020, entitled “System and Method for Dental Ventilation”, which is hereby incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63073498 | Sep 2020 | US |
