Patent Application
20190055024
The present invention concerns an apparatus and system for sensing air temperature within the cabin of an aircraft. More specifically, the present invention concerns a construction for an air duct assembly within an aircraft to facilitate accurate cabin air temperature measurement using a passive air flow through the ducting. A system also is provided.
As should be apparent to those skilled in the construction of aircraft, it is desirable to maintain the temperature of the air within the cabin of an aircraft within certain ranges for the comfort of passengers and crew.
The temperature of the air within the cabin of an aircraft typically is measured by one or more temperature sensors that are placed within a moving airstream within a duct of the heating, ventilation, and air conditioning (“HVAC”) system on board the aircraft.
To maintain an air flow that is sufficient to provide a reliable temperature measurement, it has been customary to install a temperature sensing enclosure into a dedicated air duct that interfaces with the cabin environment. The temperature sensing enclosure encompasses the temperature sensors and a fan to generate the air flow through the temperature sensing enclosure.
As should be apparent to those skilled in the art, the enclosure, fan, wiring, and any control systems associated with the temperature sensing enclosure all add weight to the aircraft. As also should be apparent to those skilled in the art, aircraft designers are motivated to reduce the overall weight of an aircraft.
In addition, the enclosure, fan, wiring, and control systems associated with the temperature sensing enclosure increase the complexity of the systems on board the aircraft. Increased complexity may, in some instances, translate into a greater probability of failure, thereby having a negative impact on cabin temperature control performance and overall reliability of the aircraft.
Additional system components also result in increased complexity for maintenance schedules and increased time invested in evaluating failure analysis scenarios.
As should be apparent, by simplifying the air duct assembly in an aircraft, considerable savings may be realized by the aircraft designer and manufacturer. Separately, the components on board an aircraft typically are subject to strict certification standards set forth by various aviation regulatory agencies worldwide. Accordingly, aircraft designers are motivated to eliminate components to reduce the regulatory burdens associated therewith.
In short, there are many reasons why eliminating one or more components on an aircraft is considered to be beneficial. However, with the temperature sensing enclosure known in the prior art, no solutions have been forthcoming.
Simply, the prior art does not provide a suitable solution to one or more of the difficulties enumerated above.
The present invention addresses one or more of the deficiencies with respect to the prior art.
The present invention provides for an air temperature sensing apparatus for an aircraft that includes an ejector with a first air duct for receiving a first air flow from an aircraft air distribution duct, the first air duct defining a first cross-sectional area, a second air duct for receiving a second air flow from a passenger compartment of the aircraft, the second air flow merging with the first air flow downstream of the second air duct, and a restrictor connected to the first air duct defining a minimal cross-sectional area. The apparatus also includes a temperature sensor in fluid communication with the second air flow. The minimal cross-sectional area of the restrictor is smaller than the first cross-sectional area of the first air duct so as to create a region of low pressure within the ejector, causing the second air flow to be suctioned over the temperature sensor and through the second air duct.
In one contemplated embodiment, the restrictor defines a restrictor length, the restrictor decreasing in cross-sectional area over at least a portion of the restrictor length to the minimal cross-sectional area.
In another embodiment, the minimal cross-sectional area is upstream of a location where the second air duct connects to the restrictor.
Still further, the minimal cross-sectional area may be at a location where the second air duct connects to the restrictor.
It is contemplated that the ejector may include a housing disposed around an end of the first air duct and the restrictor, where the second air duct connects to the housing, and where the minimal cross-sectional area is downstream of a location where the second air duct connects to the housing.
The restrictor may increase in cross-sectional area over at least a portion of the restrictor length downstream of the minimal cross-sectional area.
In an alternative embodiment, the minimal cross-sectional area may remain constant over at least a portion of the restrictor length.
In one or more embodiments, the temperature sensor may be located within the second air duct.
The present invention also may include a controller connected to the temperature sensor.
In some embodiments, the ejector may have a third air duct, connected to the restrictor.
Where a third air duct is provided, the third air duct may be connected to the housing.
In another embodiment, the apparatus may include a flow balancing device disposed in the second air duct altering the second air flow in proportion to the first air flow.
The apparatus also may have a piccolo extending from the first air duct to the flow balancing device, altering the second air flow in response to a pressure of the first air flow.
The present invention also is directed to a system for sensing air temperature within an aircraft that includes an air distributor, an ejector with a first air duct for receiving a first air flow from an aircraft air distribution duct, the first air duct defining a first cross-sectional area, a second air duct for receiving a second air flow from a passenger compartment of the aircraft, the second air flow merging with the first air flow downstream of the second air duct, and a restrictor connected to the first air duct defining a minimal cross-sectional area. The system also may include a temperature sensor in fluid communication with the second air flow and a controller connected to the temperature sensor to receive temperature information from the temperature sensor. The minimal cross-sectional area of the restrictor is smaller than the first cross-sectional area of the first air duct so as to create a region of low pressure within the ejector, causing the second air flow to be suctioned over the temperature sensor and through the second air duct.
The system may be designed such that the restrictor defines a restrictor length, the restrictor decreasing in cross-sectional area over at least a portion of the restrictor length to the minimal cross-sectional area.
The system also may be constructed so that the restrictor increases in cross-sectional area over at least a portion of the restrictor length downstream of the minimal cross-sectional area.
Still further, the system may be arranged where the minimal cross-sectional area remains constant over at least a portion of the restrictor length.
In one embodiment of the system, the minimal cross-sectional area may be upstream of a location where the second air duct connects to the restrictor.
In another embodiment of the system, the minimal cross-sectional area may be at a location where the second air duct connects to the restrictor.
In the system, the ejector may include a housing disposed around an end of the first air duct and the restrictor, where the second air duct connects to the housing. In this embodiment, the minimal cross-sectional area may be downstream of a location where the second air duct connects to the housing.
In the system of the present invention, the temperature sensor may be located within the second air duct.
For the system, it is contemplated that the ejector may have a third air duct, connected to the restrictor. The third air duct may be connected to the housing.
The system also may include a flow balancing device disposed in the second air duct altering the second air flow in proportion to the first air flow.
In addition, the system may have a piccolo extending from the first air duct to the flow balancing device, altering the second air flow in response to a pressure of the first air flow.
Further aspects of the present invention will be made apparent from the paragraphs that follow.
The present invention will now be described in connection with the drawings appended hereto, in which:
The present invention will now be described in connection with one or more embodiments thereof. The discussion of the embodiments is not intended to be limiting of the present invention. To the contrary, any discussion of embodiments is intended to exemplify the breadth and scope of the present invention. As should be apparent to those skilled in the art, variations and equivalents of the embodiment(s) described herein may be employed without departing from the scope of the present invention. Those variations and equivalents are intended to be encompassed by the scope of the present patent application.
The inlet air 18 is drawn into the temperature sensing enclosure 12 by operation of a fan 20 that is positioned within the temperature sensing enclosure 12. The inlet air 18 is then discharged into an outlet section 22 connected to the temperature sensing enclosure 12. The flow of the air in the outlet section 22 is referred to as “outlet air” 24. The outlet air 24 is discharged from the outlet section 22 of the air duct assembly installation 10 through the outlet 26 back into the cabin or cockpit of the aircraft. Alternatively, the outlet 26 may be installed to discharge the outlet air 24 in another area of the aircraft as opposed to the cabin or cockpit (e.g., a zone between the interior liner and the fuselage of the aircraft). It is contemplated that the outlet air 24 may be discharged in any area or zone within the aircraft as required or as desired by the aircraft manufacturer.
With continued reference to
The control system 32 may be an Environment Control System controller (also known as an “ECS controller”) that is able to regulate the air temperature within the cabin through control of an air conditioning unit or heater, as needed. Separately, the control system 32 may be a separate system that feeds data to the ECS controller for the aircraft.
With respect to
Without limiting the scope of the present invention, the temperature sensing apparatus 44 is broadly characterized as a device that permits accurate air temperature readings by causing a flow of air from the cabin and/or the cockpit of the aircraft 38 to flow past the temperature sensor 45. The present invention relies on passive generation of air flow across the temperature sensor 45, as discussed in greater detail herein.
The temperature sensing apparatus 44 of the present invention operates according to Bernoulli's Law, which states generally that the speed of a fluid increases simultaneously with a decrease in the pressure of the fluid or a decrease in the fluid's potential energy. This principle is named after Daniel Bernoulli, who published the details of this principle in his book, entitled Hydrodynamica, in 1738.
As illustrated in
For reference, a first inlet 60 is provided into the first air duct 50. A second inlet 62 is provided into the second air duct 54. An air outlet 64 is provided at the outlet of the third air duct 58. As should be apparent, the inlets 60, 62 and the outlet 64 are merely illustrative of the embodiment depicted in
In operation, it is contemplated that the first air flow 48 passing through the first air duct 50 is air that is being supplied as part of the air supply of the air distribution system 40 in the interior of aircraft 38. The second air flow 52 entering the second inlet 62 is drawn directly from the cabin and/or cockpit of the aircraft 38. The second air flow 52 passes over the temperature sensor 45, which measures the temperature of the second air flow 52. As a result, the temperature sensor 45 measures the temperature of the air in the cabin and/or cockpit of the aircraft 38. The temperature sensor 45 is connected, via wiring 66, to an environmental control system 68.
It is contemplated that the environmental control system 68 will be associated with the cooling, heating, and ventilation controls provided on board the aircraft 38. However, the signal provided to the environmental control system 68 may be associated with a zone or region within the aircraft 38 and other temperature sensor signals associated with other zones may provide signals to the same master environmental control system on board the aircraft 38. For purposes of the present invention, therefore, the environmental control system 68 may be a stand-alone system or may be a system designed to interface with one or more other environmental controllers on board the aircraft 38. In other words, the environmental control system 68 should not be understood to refer only to a single component on the aircraft 38.
With continued reference to
With respect to the temperature sensor 45, the present invention contemplates reliance on a thermocouple. However, any suitable temperature sensor may be employed without departing from the scope of the present invention.
With continued reference to
In operation, as the first air flow 48 within first air duct 70 increases its velocity through the restrictor 78 due to the minimal cross-sectional area, a region of low pressure is created in and after the restrictor 78 and, therefore, also within the region 76 downstream of the restrictor 78. The low pressure generates a suction force that draws the second air flow 52 through the second air duct 54, into the second air duct 72 of the ejector 46. As illustrated, the second air flow 52 travels through the second air duct 72 and over the temperature sensor 45.
The geometry and shape of the ejector 46 and the restrictor 78 contribute to the efficiency of the second air flow 52 over the temperature sensor 45. The geometry and shape of the ejector 46 and the restrictor 78 also influence the sizing of the ejector 46. As should be apparent, the geometry and shape of the ejector 46 and the restrictor 78 are anticipated to be tailored for applications in different airplanes and for different air distribution architectures. Accordingly, specific dimensions are expected to vary from one installation to the next.
It is contemplated that the restrictor 78 may decrease the cross-sectional area of the first air duct 70 within a range of between about 10-70%. In other embodiments, the restriction is contemplated to be between 20-60%, 30-50%, or about 40%, as required or as desired. In selected embodiments, the restriction is contemplated to fall within a range of about 35-45%, with an average restriction being about 40%. Still other embodiments are contemplated to fall within the scope of the present invention.
The ejector 46 is contemplated to include at least the first air duct 70, the second air duct 72, and the restrictor 78. The first air duct 70, the second air duct 72, and the restrictor 78 are operationally connected to one another. The third air duct 74 also may be considered to be a part of the ejector 46 depending on the configuration of the ejector 46. Still further, the ejector 46 may include an additional housing. As detailed with respect to the embodiments illustrated in
The air temperature sensing apparatus 44 is contemplated to encompass at least the ejector 46 and the temperature sensor 45. The temperature sensor 45 is contemplated to be positioned in the second air duct 72.
As noted, the restrictor 78 defines a minimal cross-sectional area that is smaller than the first cross-sectional area of the first air duct 70. The minimal cross-sectional area creates a region of low pressure within the ejector 46, causing the second air flow 52 to be suctioned over the temperature sensor 45 and through the second air duct 72.
As discussed in connection with one or more of the embodiments described in connection with
The minimal cross-sectional area 144, 162, 194 may be upstream of a location where the second air duct 72 connects to the restrictor 78. Alternatively, the minimal cross-sectional area may be at the location where the second air duct 72 connects to the restrictor 78. Still further, the ejector 46 may include a housing 168 that is disposed around an end of the first air duct 70 and the restrictor 78. In this embodiment, the minimal cross-sectional area 194 is contemplated to be downstream of a location where the second air duct 72 connects to the housing 168.
In
As also illustrated in
As also should be apparent to those skilled in the art, the environmental air control system 68 on an aircraft 38 generates different flow rates for the first air flow 48 at different altitudes. The first air flow 48, therefore, is not a constant at all times. Instead, the first air flow 48 is a changing variable. For a number of reasons, as the altitude of the aircraft 38 changes, the control system 68 alters the first air flow 48. Cabin pressure differences and different air densities encompass some of the variables that the control system 68 takes into account to alter the first air flow 48.
While not considered limiting of the present invention, it is contemplated that the first air flow 48 will be at least five times (5×) the rate of the second air flow 52 (in scfm). This is considered to be a minimum magnitude for the first air flow 48 to allow an effective operation of the ejector 46. Under normal operating conditions, the first air flow 48 is contemplated to be controlled within a typical range of between about 40-180 scfm (0.0188-0.0850 m3/s). As should be apparent to those skilled in the art, the exact flow may vary for any number of reasons. For example, the sizes and shapes of the various ducts are expected to be factors contributing to the magnitude of the first air flow 48, the second air flow 52, and the third air flow 56.
In one contemplated embodiment, the environmental control system 68 may alter the first air flow 48 as a result of a temperature change in the cabin air. The temperature change may be the result of a change in environmental conditions. The temperature change also may result from a change in a thermostat setting to accommodate the comfort of the passengers and/or crew. As such, there are a number of factors that the control system 68 takes into account when adjusting the first air flow 48.
In addition, the number of air conditioning units operating will contribute to the magnitudes of the different air flows 48, 52, 56. Under normal operation, all of the air conditioning units should be available for operation in the aircraft 38. In an abnormal and/or a failure mode of operation, at least one air conditioning unit might be inoperative, causing reductions in the air flows 48, 52, 56 within the air distribution system 40. Here, the ejector 46 may be sized to meet at least the minimum air flow requirements when one air conditioning unit is inoperative. As should be apparent, reduced air flows might impact the operation of the ejector 46.
An aircraft 38 with a more sophisticated cabin air management systems (including the environmental control system 68) is contemplated to take into account other variables including, but not limited to, the number of passengers on board the aircraft 38. Passengers add heat to the environment within the cabin and, therefore, may be considered as a variable to define the optimized air flow required for the cabin.
It is contemplated that the shape, size, and position of the ejector 46 in the air distribution system 40 will be constructed to operate over a range of magnitudes for the first air flow 48. As such, the ejector 46 will generate different magnitudes for the second air flow 52 proportional to the magnitude of the first air flow 48.
The ejector 46 is contemplated to provide an internal shape, adjacent to the temperature sensor 45, to assure an accurate measurement of the temperature of the second air flow 52 and, therefore, of the temperature of the air in the cabin of the aircraft 38.
As discussed, the cross-sectional shapes of the first air duct 70, the second air duct 72, and the third air duct 74 are contemplated to play a role in the operation of the ejector 46. In the context of the present invention, the cross-sectional shapes are contemplated to be circular. However, the first air duct 70, the second air duct 72, and the third air duct 74 may be designed with any alternative cross-sectional shape without departing from the scope of the present invention.
In addition, the angles at which the three air ducts 70, 72, 74 intersect one another may play a role in the operation of the ejector 46. It is contemplated, for example, that the ejector 46 will have a generally Y-shape with the first and third air ducts 70, 74 being approximately parallel and collinear with one another. In this configuration, the second air duct 72 is contemplated to be disposed at an angle that may vary from about 30° to about 75° with respect to the first and third air ducts 70, 74. As should be apparent, this is merely an example and is not intended to be limiting of the present invention.
As may be apparent, the angle of the second air duct 72 with respect to the first and third air ducts 70, 74 is contemplated to be selected to promote the second air flow 52 through the second air duct 72 and, thereby, to contribute to the optimization of the installation of the temperature sensor 45, improving accuracy of the temperature readings generated thereby. While an angle of 45° is illustrated, any suitable angle may be employed. Angles of 40-50°, 35-55°, 30-60°, and 50-70° are contemplated to fall within (but not limit) the present invention. Ranges between about 30° to about 45° or about 50° to about 70° appear to be suitable for establishing acceptable operating conditions. Specific suitable angles include, but are not limited to 30°, 45°, and 60°.
As should be apparent from the foregoing, there are a number of advantages that are presented by the temperature sensing apparatus 44 of the present invention. First, by eliminating the temperature sensing enclosure 12 and fan 20, there is a reduction in the number of components installed on board the aircraft 38. This reduces the complexity and weight of the aircraft 38, along with providing other advantages. Second, by eliminating the fan 20, the electrical system on the aircraft 38 is simplified. Third, by simplifying the system on the aircraft 38, there are fewer components that may fail, and/or present dormant failure conditions. As a result, maintenance of the aircraft 38 may be simplified and the reliability of the aircraft 38 may be improved.
The second temperature sensing apparatus 84 differs from the first temperature sensing apparatus 44 in that the second temperature sensing apparatus 84 includes a flow balancer 86. The flow balancer 86 includes a piccolo 88 that extends from the first air duct 70 of the ejector 90 to the second air duct 72. The second air duct 72 of the ejector 90 include a flow balancing device 92 installed upstream of the temperature sensor 45.
As shown in
In the illustrated embodiment, the inner diameter of the orifice 96 is the same as the inner diameter of the second air duct 72. Accordingly, when the cylinder 94 is in the fully opened position such that the cylinder 94 compresses the spring 102 at least partially (
Motive power for the operation of the cylinder 94 is provided by air in the piccolo 88. In particular, air pressure 106 in the piccolo 88 is contemplated to be equivalent to (or nearly equivalent to) the pressure of the first air flow 48 in the first air duct 50. The pressure of the first air flow 48 also is contemplated to be the same in the first air duct 70, immediately upstream of the restrictor 78. The piccolo 88 connects the first air duct 70 to the cylinder 94, thereby applying that pressure to the end of the cylinder 94. The cylinder 94 acts like a piston and moves linearly in the housing 98, as biased by the spring 102, in proportion to the pressure 106 of the first air flow 48.
When in the closed condition, the cylinder 94 is biased by the spring 102 such that the inner diameter 108 of the opening 96 is not in register with the inner diameter 110 of the second air duct 72. Here, the inner diameter 108 of the opening 96 is nearly non-overlapping with the inner diameter 110 of the second air duct 72. In this closed position, it is contemplated that there will remain a small opening 112 to avoid the creation of any back pressure in the second air duct 72 and, thereby, avoid locking the cylinder 94 in the housing 98 as a result of the back pressure.
The operation of the cylinder 94 as illustrated in
The opening and partial occlusion of the opening 112 in
As should be apparent from the discussion above, the opening 112 is contemplated to decrease in overall area as the second air flow progresses from the minimum value (
Consistent with the embodiments of temperature sensing apparatuses 44, 84, the temperature sensing apparatus 114 includes an ejector 116. The ejector 116 comprises a first air duct 118 for receiving a first air flow 120 from an aircraft air distribution duct, a second air duct 122 for receiving a second air flow 124 from a passenger compartment of the aircraft, and a third air duct 126 comprising third air flow 128. The ejector 116 includes a restrictor 130 that is defined, in part, by a restrictor length 132 extending between the first air duct 118 and the third air duct 126.
With respect to this embodiment and the remaining contemplated embodiments, it is noted that the third air duct 126 is not contemplated to be needed for all configurations of the present invention. It is contemplated that, after the first air flow 120 and the second air flow 124 are combined, the combined air flow may be discharged directly into the environment rather than being conducted by the third air duct 126 to another location.
As shown in
While the first air duct 118, the second air duct 122, and the third air duct 126 are illustrated as being cylindrical in cross-section for the embodiment of the temperature sensing apparatus 114, the present invention is not intended to be limited solely to such a construction. In alternate contemplated embodiments, one or more of the first air duct 118, the second air duct 122, and third air duct 126 may have cross-sectional shapes that are elliptical, oval, semi-circular, rectangular, square, triangular, polygonal, and/or amorphously shaped, among others. In these alternative embodiments, the first cross-sectional area 134, the second cross-sectional area 136, and the third cross-sectional area 138 will not be circular in shape, as should be apparent to those skilled in the art.
Consistent with the embodiments of temperature sensing apparatuses 44, 84, the temperature sensor 140 is disposed within the second air duct 122.
As should be apparent from
In the embodiment illustrated in
The restrictor 130 defines a minimal cross-sectional area 144 at approximately a midpoint of the restrictor length 132. As a result, the restrictor 130 is constructed with a decreasing cross-sectional area over at least a portion of the restrictor length 132 to the minimal cross-sectional area 144. Still further, the restrictor 130 is constructed with an increasing cross-sectional area over at least a portion of the restrictor length 132 downstream of the minimal cross-sectional area 144. In a further contemplated embodiment, the minimal cross-sectional area 144 may remain constant over at least a portion of the restrictor length 132.
As discussed in connection with
Concerning the embodiment illustrated in
As discussed above, the restrictor 130 defines a minimal cross-sectional area 144 that is less than the first cross-sectional area 134 of the first duct 118 and, in some contemplated embodiments, also less than the third cross-sectional area 138 of the third duct 126. As a result of the Venturi effect, the speed of the air passing through the restrictor 130 is increased. This increase in the air speed creates a suction that draws the second air flow 124 into the second air duct 122.
As should be apparent from
While the angle α is illustrated as being 60° for this embodiment and any other embodiment, it should be understood that the present invention is not limited solely to this construction. Other suitable angles include, but are not limited to 30°±10°, 45°±10°, 60°±10°. Still other suitable angles include 30°±5°, 45°±5°, 60°±5°.
In embodiments where the minimal cross-sectional area 144 remains constant for a portion of the length 132 of the restrictor 130, it is contemplated that the second air duct 122 may connect at a position along the length of the minimal cross-sectional area 144, consistent with the illustrations in
It is noted that the restrictor length 132, 154 is not intended to be limiting of the scope of the present invention. The restrictor length 132, 154 may be varied to accommodate any number of configurations and environmental constraints, as should be apparent to those skilled in the art.
As should be apparent from a comparison of
It is noted that the second air duct 122 need not connect to the restrictor 130, 152, 158 to practice the present invention. Instead, the second air duct 122 may connect to the third air duct 126, downstream of the minimal cross-sectional area 144, 162, without departing from the scope of the present invention.
This embodiment of the temperature sensing apparatus 164 differs from the prior embodiments. However, the principle of operation, i.e., by the Venturi effect, remains the same.
The temperature sensing apparatus 164 includes a first air duct 166 that extends into a housing 168. The first air duct 166 terminates in a restrictor 170. In this embodiment, the restrictor 170 is a necked-down element that is attached to or integrally formed with the end of the first air duct 166. As before, the restrictor 170 defines a restrictor length 200 and a minimal cross-sectional area 194, discussed in greater detail below.
The restrictor 170 is interior to the housing 168. The housing 168 encloses both a portion of the first air duct 166 and the restrictor 170. The housing 168 has a closed end 172 through which the first air duct 166 passes into the interior of the housing 168. The housing also includes a main housing section 174 extending from the closed end 172 and a conical housing section 176 connected to the main housing section 174.
A second air duct 178 connects to the main housing section 174 at a periphery thereof, upstream of the restrictor 170. A third air duct 180 attaches to the end of the conical housing section 176.
As in the prior embodiments, a first air flow 182 is received in the first air duct 166. As discussed above, the first air flow 182 is contemplated to be supplied as a part of the air supply of the air distribution system 40 on board the aircraft 38. The second air duct 178 receives a second air flow 184 from a passenger compartment of the aircraft. The third air duct 180 receives a third air flow 186, which is a combination of the first air flow 182 and the second air flow 184. The first air duct 166 defines a first cross-sectional area 188. The second air duct 178 defines a second cross-sectional area 190. The third air duct 180 defines a third cross-sectional area 192. The end of the restrictor 170 defines a minimal cross-sectional area 194.
As in prior embodiments, the first air duct 166 and the third air duct 180 are collinear, sharing the same common axis 196. The second air duct 178 connects to the main housing section 174 at an angle α of 60°, as in prior embodiments. However, the angle α of attachment may differ from the illustrated embodiment without departing from the scope of the present invention. While not limiting of the present invention, it is contemplated that the angle α of attachment of the second air duct 178 to the main housing section 174 may fall within the ranges discussed in connection with other embodiments.
As in prior embodiments, the temperature sensor 198 is disposed in the second air duct 178.
In the embodiments depicted in
So as not to be construed as limiting of the present invention, the restrictor length 202 may have any suitable magnitude as required or as desired. Furthermore, the shape of the restrictor 170 should not be understood as being limited to a conical shape. The restrictor 170 may have any suitable cross-sectional shape between the first cross-sectional area 188 to the smaller, minimal cross-sectional area 194 without departing from the scope of the present invention.
This embodiment is similar to the temperature sensing apparatus 164, except that the restrictor 170 further includes an additional section 206. The additional section 206 defines a length 208 where the minimal cross-sectional area 194 remains constant over a portion of the restrictor length 200. The outlet 210 of the restrictor 170 lies within the conical housing section 176, but does not extend as far as the transition point 212 between the conical housing section 176 and the third air duct 180.
This embodiment is similar to the embodiment illustrated in
This embodiment is similar to the embodiment illustrated in
As should be apparent from the embodiments illustrated in
As noted above, the embodiment(s) described herein are intended to be exemplary of the wide breadth of the present invention. Variations and equivalents of the described embodiment(s) are intended to be encompassed by the present invention, as if described herein.
This patent application relies for priority on U.S. Provisional Patent Application Ser. No. 62/239,002, filed on Oct. 8, 2015, the entire contents of which are incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2016/056027 | 10/7/2016 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62239002 | Oct 2015 | US |
