Patent Publication Number: US-11029023-B2

Title: System and method for generating flame effect

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 14/258,981, entitled “SYSTEM AND METHOD FOR GENERATING FLAME EFFECT,” filed Apr. 22, 2014, which is hereby incorporated by reference in its entirety for all intents and purposes. 
    
    
     BACKGROUND 
     The present disclosure relates generally to flame effects and, more particularly, to a system and method for generating flame effects using a fuel nozzle system. 
     Flame effects (e.g., visible flame outputs) are used to provide an aesthetic display for patrons and others across a wide variety of applications and industries, including in the fireworks industry, the service industry (e.g., restaurants, movie theaters), and in amusement parks, among others. Flame effects generally include ignition and/or burning of one or more fuels. For example, a torch displayed in a restaurant may include a wick that is soaked in a fuel (e.g., kerosene) configured to burn upon ignition. The burning kerosene and wick may produce a flame effect that releases ambient light for patrons in the restaurant. 
     Flame effects may be more aesthetically appealing and impressive when they are large and colorful. For example, a flame effect with a large, orange flame may be more appealing and impressive than a flame effect with a small, light-yellow flame. Further, a small, light-yellow flame may not be visible, fully or partially, in outdoor applications on a bright afternoon. Indeed, in outdoor applications in particular, flame effects may be visibly different at different times of the day or year depending on environmental factors (e.g., sunlight, weather, pollution, wind conditions). Unfortunately, colorful flame effects generally coincide with incomplete combustion, and incomplete combustion generally results in pollution via residual materials (e.g., pollutants) commonly referred to as soot or ash. Thus, it is now recognized that there exists a need for improved systems and methods for generating flame effects that balance cleanliness, efficiency, and coloration, such that the flame effects are aesthetically appealing, clean burning, cost-effective, clearly visible at any given time during operation, and adaptable to environmental factors. 
     BRIEF DESCRIPTION 
     Certain embodiments commensurate in scope with the originally claimed subject matter are summarized below. These embodiments are not intended to limit the scope of the disclosure, but rather these embodiments are intended only to provide a brief summary of certain disclosed embodiments. Indeed, the present disclosure may encompass a variety of forms that may be similar to or different from the embodiments set forth below. 
     In accordance with one aspect of the present disclosure, a system includes a nozzle assembly with an outer nozzle and an inner nozzle. At least a portion of the inner nozzle is nested within at least a portion of the outer nozzle. The system also includes a fuel source with two or more separate types of fuel. 
     In accordance with another aspect of the present disclosure, a system includes an automation controller configured to regulate a fuel source to control a fluid flow from the fuel source to a first nozzle and to a second nozzle of a nozzle assembly based on environmental factors surrounding the system. 
     In accordance with another aspect of the present disclosure, a method of operating a system includes determining environmental factors around the system and fluidly coupling a first type of fuel from a fuel source that has two or more separate fuel types with a first nozzle and a second type of fuel from the fuel source with a second nozzle. The method of operation also includes passing the first type of fuel through the first nozzle at a first pressure, passing the second type of fuel through the second nozzle at a second pressure, and passing the first type of fuel and the second type of fuel over an ignition feature, such that the first type of fuel and the second type of fuel ignite to generate a flame effect. 
     Subsystems and components that make up the flame effect system include various features that individually or cooperatively enable efficient utilization of fuel, control and management of flame characteristics, relative positioning of flame elements, control of flame features based on environmental conditions, control of associated debris (e.g., soot and ash), and enhanced operational characteristics. These different features and their specific effects are described in detail below. 
    
    
     
       DRAWINGS 
       These and other features, aspects, and advantages of the present disclosure will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
         FIG. 1  is a schematic block diagram of an embodiment of a flame effect system including a nozzle assembly and controls system, in accordance with the present disclosure; 
         FIG. 2  is a perspective view of an embodiment including a portion of the flame effect system including a nested nozzle assembly and control system features integrated with a dragon model, in accordance with the present disclosure; 
         FIG. 3  is a perspective view of an embodiment of a nozzle assembly including nested nozzles, in accordance with the present disclosure; 
         FIG. 4  is a cross-sectional view of an embodiment of a nozzle assembly including nested convergent-divergent nozzles, in accordance with the present disclosure. 
         FIG. 5  is a front view of the nozzle assembly of  FIG. 4 , in accordance with the present disclosure; 
         FIG. 6  is a cross-sectional view of an embodiment of a nozzle assembly including three nozzles in a nested arrangement, in accordance with the present disclosure; 
         FIG. 7  is a front view of the nozzle assembly of  FIG. 6 , in accordance with the present disclosure; 
         FIG. 8  is a cross-sectional view of an embodiment of a nozzle assembly including two converging nozzles, in accordance with the present disclosure; 
         FIG. 9  is a cross-sectional view of an embodiment of a nozzle assembly including two substantially straight walled nozzles, in accordance with the present disclosure; 
         FIG. 10  is a cross-sectional view of an embodiment of a nozzle assembly including two nested nozzles, in accordance with the present disclosure; 
         FIG. 11  is a perspective view of an embodiment of a nozzle assembly including two nested nozzles, in accordance with the present disclosure; 
         FIG. 12  is a schematic block diagram of a nozzle assembly, in accordance with the present disclosure; and 
         FIG. 13  is a method of operating a system including a nozzle assembly, in accordance with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Presently disclosed embodiments are directed to systems and methods for generating and controlling flame effects that may be aesthetically appealing, clearly visible during operation, substantially clean burning, cost-effective, and adaptable to environmental factors (e.g., sunlight, weather, pollution, wind conditions). Presently disclosed embodiments include systems and methods that utilize nozzle assemblies with nested nozzles that facilitate providing desired flame characteristics. For example, present embodiments may control the quantities of fuel, pressures of fuel, types of fuel, and so forth that flow through the various nozzles of a nested nozzle assembly to achieve certain flame characteristics (e.g., projection distance, arrangement of gas envelopes, visibility, soot content, soot scattering patterns). Present embodiments may include or employ converging-diverging nozzles (e.g., de Laval nozzles) with nozzle assemblies for generating flame effects to encourage specific flame characteristics. For simplicity, the converging-diverging nozzles may be referred to herein as “Laval nozzles”. It should be noted, however, that embodiments of the present disclosure encompass any converging-diverging nozzles configured to accelerate gas through such nozzles. 
     Turning first to  FIG. 1 , a schematic block diagram is shown that includes an embodiment of a flame effect system  10  in accordance with the present disclosure. The system  10  may include, among other things, a nozzle assembly  12 . In the illustrated embodiment, the nozzle assembly  12  includes an inner nozzle  14  and an outer nozzle  16 , where at least a portion of the inner nozzle  14  is nested within and generally concentric with at least a portion of the outer nozzle  16 . In one embodiment, the inner and outer nozzles  14 ,  16  may include portions that are axially symmetric and/or planar symmetric, but are not entirely concentric. In embodiments in accordance with the present disclosure, the nozzle assembly  12  is configured to produce a flame effect  17  (e.g., plume of fire) that is clearly visible and adaptable to environmental factors. 
     The nozzle assembly  12  in the illustrated embodiment is configured to produce the flame effect  17  by accelerating or passing fuels (e.g., gaseous or substantially gaseous fuels) through the inner nozzle  14  and the outer nozzle  16 . In some embodiments, a regulation device may regulate pressure (and, thus, flow rate) and/or temperature of the fuels (e.g., prior to reaching the nozzles  14 ,  16 ), such that the fuels are delivered to the nozzles  14 ,  16  at a high enough flow rate to enable the fuels to accelerate or pass through and, in some embodiments, mix within the nozzle assembly  12 . For example, in one embodiment, the inner nozzle  14  and the outer nozzle  16  may each include a converging portion and a diverging portion. The converging and diverging portions may be configured to accelerate the gases through the nozzles  14 ,  16 . In another embodiment, the nozzles  14 ,  16  may only include a converging portion or the nozzles  14 ,  16  may only include a diverging portion. In either embodiment, the nozzles  14 ,  16  are each configured to restrict a path through which fuel gas or gases flow, such that operational pressures of the flame effect system  10  (e.g., pressures supplied by the regulation device) may be minimized while still passing the gases through, and mixing the gases within, each of the nozzles  14 ,  16 . Further, the inner nozzle  14  may terminate within the outer nozzle  16 , such that gas flowing through the enter nozzle enters into a central portion of the outer nozzle  16 . Depending on the embodiment, the gases may remain substantially separate within the outer nozzle  16 , or the gases may mix within the outer nozzle  16 . Such embodiments will be discussed in detail below with reference to later figures. It should be noted that in some embodiments, fluid (e.g., gases) other than fuel may be used to produce different effects (e.g., a fog related effect). Also, some embodiments may use both fuel and non-fuel fluids. Fuel gas is often used as a specific example in the present disclosure, but it should be understood that other fluids may be employed. 
     After passing through the nozzles  14 ,  16  (or before acceleration in some embodiments), the gaseous fuels are ignited to produce the flame effect  17 . In the illustrated embodiment of  FIG. 1 , the gaseous fuels pass through the nozzles  14 ,  16 , exit the nozzle assembly  12  at high speeds and pass over an ignition feature  18  (e.g., an igniter), which includes a pilot light that lights or ignites the gaseous fuels as they pass the pilot light to produce the flame effect  17 . The flame effect  17  is carried a distance away from the nozzle assembly  12  due to the speed at which the hot gaseous fuels exit the nozzle assembly  12 . Further, the flame effect  17  may include specific characteristics based on various factors. For example, the contours of the flow paths in the nozzles  14 ,  16  of the nozzle assembly  12 , the type of fuel used, which nozzle  14 ,  16  the different types of fuel are supplied through, the pressure of the fuel, and so forth define characteristics of the flame effect  17 , as will be discussed in detail below. 
     In the illustrated embodiment of  FIG. 1 , the system  10  includes a fuel source  20  which includes gaseous fuels that are accelerated through the nozzle assembly  12 , as described above. The fuel source  20  may include multiple compartments or tanks (e.g., a first tank  22 , a second tank  24 , and a third tank  26 ), and each tank may include a different type of fuel. One or more (or all) of the tanks may include combustible fuel and one or more of the tanks may include non-combustible material or some other fluid (e.g., oxidant, inert gas, or diluents). For example, the first tank  22  in the illustrated embodiment may include propane, the second tank  24  may include natural gas, and the third tank  26  may include nitrogen or some other inert gas. However, in another embodiment, one or more of the tanks may include some other type of fuel or fluid not listed above, such as oxygen. 
     Further, an automation controller  28 , which includes a processor  30  and a memory  32 , may provide outputs that initiate fluidly coupling of one of the tanks  22 ,  24 ,  26  with a fluid passageway for either one of the inner or outer nozzles  14 ,  16 , as described above. In the illustrated embodiment, one of the tanks  22 ,  24 ,  26  may be placed in fluid communication with a fluid passageway  34  of the inner nozzle  14  and another one of the tanks may be placed in fluid communication with a fluid passageway  36  of the outer nozzle  16 . For example, the automation controller  28  may operate to place the first tank  22  having a propane supply in fluid communication with the fluid passageway  36  of the outer nozzle  16  and to place the second tank  24  having natural gas supply in fluid communication with the fluid passageway  34  of the inner nozzle  14 . The automation controller  28  may provide outputs based on one or more control algorithms that take into account one or more input values (e.g., manual inputs, sensor measurement values, data feeds). For example, in the illustrated embodiment, the automation controller  28  receives input from an Internet system  37 , which is merely one example of a communication network, a sensor  38  disposed in an environment  40  proximate the flame effect  17 , or both. Further, the inputs into the automation controller  28  may be analog, digital, or both. The Internet system  37  (or a different communication network) and the sensor  38 , or some other device or input to the automation controller  28 , provide the automation controller  28  with information relating to environmental factors in the environment  40 . For example, the environmental factors may include brightness, pollution, sunlight, weather, time of day, humidity, wind conditions, soot levels from the flame effect  17  or some other environmental factor. In some embodiments, each of the inner nozzle  14  and the outer nozzle  16  may include its own corresponding fuel source, automation controller, sensors, Internet system, program, and/or memory. Further, in some embodiments, more than two nested nozzles or sets of nested nozzles may be employed. 
     The automation controller  28  may include a burner controller  41  in addition to the processor  30 . The burner controller  41  is configured to initiate an ignition sequence upon receiving a trigger signal from the processor  30 . The burner controller  41  ignites the ignition features  18  (e.g., an igniter), confirms ignition of the ignition feature  18 , and then proceeds to release the fuel from the fuel source  20  to the nozzles  14 ,  16 , which consequently ignites the fuels to generate the flame effect  17 . The processor  30  may then analyze all incoming information (e.g., digital or analog signals from the sensor  38 , the Internet system  37 , or some other input) and determine whether to signal the burner controller  41  to begin the ignition sequence again. 
     The processor  30  (e.g., of the automation controller  28 ), which may represent multiple processors that coordinate to provide certain functions, may execute computer readable instructions (e.g., a computer program) on the memory  32 , which represents a tangible (non-transitory), machine-readable medium. The computer program may include logic that considers measurements from the sensor  38 , which may represent multiple different sensors, and/or Internet system  37  and determines which tank or tanks of the fuel source  20  to place in fluid communication with the fluid passageways  34 ,  36 , of the system  10  to generate the most desirable flame effect  17 . The most desirable flame effect  17  may include flame effect factors related to color of the flame effect  17 , brightness of the flame effect  17 , cleanliness of the flame effect  17 , cost-effectiveness of the flame effect  17 , length of the flame effect  17 , and/or safety of the flame effect  17 , among other factors. The computer program executed by the processor  30  may take into account all, more, or a subset of the flame effect  17  factors described above. Additionally, the automation controller  28  may cooperate with different features of the system  10  (e.g., a pump, a compressor, a bank of different or backup nozzles and nozzle arrangements) to control different aspects of the flame. For example, if the automation controller  28  determines that more pressure is needed, a compressor may be activated or an ignition source prior to the entry of the nozzles  14 ,  16  may be activated. As another example, if the controller determines that the nozzles  14 ,  16  are likely not functioning properly (e.g., due to accumulation of soot), a valve may close off access to the nozzles  14 ,  16  and direct the fuels to a set of backup nozzles. In yet another embodiment, a bank of different nozzles that provide different flame characteristics may be selected for operation by the automation controller  28  based on sensor date (e.g., certain nozzles may be preferred for windy conditions). 
     Continuing with the illustrated embodiment, the automation controller  28  is configured to open and/or close control valves  42 ,  44 , one for each of the inner nozzle  14  and the outer nozzle  16 , respectively, to enable or block fluid flow through the fuel passageways  34 ,  36  to the inner nozzle  14  and the outer nozzle  16 , respectively. The automation controller  28  may open and/or close the control valves  42 ,  44  based on measurements and/or information from the sensor  38  and Internet system  37  in the same manner as described above. In some embodiments, the automation controller  28  may open or close one or both of the control valves  42 ,  44  to a certain finite extent to regulate pressure of the fuel sent to either of the fuel passageways  34 ,  36  from the fuel source  20 . Alternatively or in combination with the above described controls aspect, the control valves  42 ,  44  may each include a regulator, or a regulator may be included in the fuel source  20 , to regulate pressure. The automation controller  28  may be instructed via the processor  30  to control the regulator or the control valves  42 ,  44  in the manner described above. In other words, in general, the automation controller  28  may regulate pressure of the fuel being supplied to the fuel passageways  34 ,  36  (and, eventually, to the inner nozzle  14  and outer nozzle  16 ) based on environmental factors supplied by the sensor  38  and/or the Internet system  37 . Further, pressure of the fuels delivered to the inner nozzle  14  and outer nozzle  16 , respectively, may be different for each of the inner nozzle  14  and outer nozzle  16 , depending on the desired flame effect. For example, to achieve approximately a 30 to 40 foot (9.1 to 12.2 meter) flame, pressure (e.g., measured in pounds per square inch (psi) and kilopascals (kPa)) of natural gas delivered to the inner nozzle  14  may, for example, range from 10 to 40 psi (69 to 276 kPa), 20 to 30 psi (138 to 207 kPa), or 22 to 28 psi (152 to 193 kPa), and pressure of propane delivered to the outer nozzle  16 , for example, may range from 1 to 20 psi (7 to 138 kPa), 5 to 15 psi (34 to 103 kPa), or 7 to 11 psi (48 to 76 kPa). It should be noted that, in some embodiments, a pulsed flame effect  17  may be achieved by delivering fuels at the above pressures or otherwise to the inner and outer nozzles  14 ,  16  in pulses. For example, the automation controller  28  may instruct the fuel source  20  (e.g., via regulators or via the control valves  42 ,  44 ) to supply propane to the outer nozzle  16  and natural gas to the inner nozzle  14  at a constant pressure in five second intervals, separated by three second intervals of cutting off the fuel source (e.g., via regulators or via the control valves  42 ,  44 ). This may result in the flame effect  17  being visible in repeated five second intervals, each separated by three second intervals. Between intervals, the automation controller  28  may cause an inert gas to pass through both nozzles  14 ,  16  to rapidly extinguish residual flame. The inert gas, in some embodiments, may also be used to discharge debris, including soot and ash, away from the nozzle assembly  12  to prevent building up within the nozzles  14 ,  16  and surrounding equipment or objects. In other words, the inert gas would not only extinguish residual flame, but may also be used to clear soot and ash already within the nozzles  14 ,  16  away from the flame effect system  10  in general. 
     Further to the discussion above, the sensor  38  disposed in the environment  40  and the Internet system  37  or other devices or communication systems may be configured to detect and/or supply data regarding a number of various environmental factors of the environment  40  to the automation controller  28 , including environmental brightness (e.g., sunlight), brightness of the flame effect  17 , pollution, temperature, wind conditions, and weather, among others. For example, the sensor  38  may detect that the environment  40  is relatively bright, and may provide information related to the brightness of the environment  40  to the automation controller  28 . The automation controller  28  may perform logic based on the information received from the sensor  38  provide output to place the first tank  22  (having propane) of the fuel source  30  in fluid communication with the second fluid passageway  36  and the second fuel tank  24  (having natural gas) of the fuel source  30  in fluid communication with the first fluid passageway  34 . The automation controller  28  may also instruct the control valves  42 ,  44  to open fully, such that the first fuel tank  22  is fluidly coupled to the outer nozzle  16  and the second fuel tank  24  is fluidly coupled to the inner nozzle  14 , where the propane is supplied to the outer nozzle  16  with the same or different pressure and flow rate as the natural gas being supplied to the inner nozzle  14 , depending on information received by the processor  30  from the sensor  38 , Internet system  37 , or some other input to the processor  30 , and depending on the desired flame effect  17 . The propane may be accelerated through the outer nozzle  16 , and the natural gas may be accelerated through the inner nozzle  14 . The gases may exit the nozzle assembly  12 , pass over the pilot light of the igniter  18 , and produce the visible flame effect  17 , where the flame effect  17  achieves an optimal combination of brightness, cost-effectiveness, and cleanliness based on the environmental factors originally supplied to the processor  30 , as described above. 
     It should be noted that, as indicated above, the processor  30  may execute a computer program (e.g., control logic) that takes into account inputs based on such factors as brightness, cost-effectiveness, and cleanliness of the flame effect  17 . Further, the computer program may weight each of these factors, and other factors, based on a desired importance of such factors. Further, the automation controller  28  may control a type of fuel supplied to each fuel passageway  24 ,  26  (and, thus to either nozzle  14 ,  16 ), and/or a flow rate (and, thus pressure) of the types of fuel supplied to either fuel passageway  24 ,  26  (and, thus, to either nozzle  14 ,  16 ). For example, in one embodiment, on a bright day, the controller  28  may instruct the above actions to ensure that the flame effect  17  burns a clearly visible color during daylight, but still cost-effectively and cleanly. Alternatively, in another embodiment, on a dark day, the controller  28  may instruct the above actions to ensure that the flame effect  17  is clean and cost-effective, but still visible. Details regarding types of fuels supplied to the inner and outer nozzles  14 ,  16  and flow rate of said fuels, with respect to achieving a desirable flame effect  17 , will be described in further detail below. 
     Turning now to  FIG. 2 , a perspective view of a portion of an embodiment of the system  10  and accompanying nozzle assembly  12  is shown disposed within a dragon model  60  (e.g., a statue or animatronic system). The system  10  may be at least partially hidden within the dragon model  60  (e.g., within a mouth  62  of the dragon  60 ), such that the flame effect  17  produced by the system  10  and the accompanying nozzle assembly  12  exits the mouth  62  of the dragon statue  60 . In other words, the system  10  in combination with the dragon statue  60  may result in the intentional illusion of a fire-breathing (e.g., exhaling) dragon  60  for entertainment value. 
     In the illustrated embodiment, components of the system  10  are generally hidden within the mouth  62  of the dragon  60 . For example, with reference to components described in  FIG. 1 , the fuel source  20 , the controller  28 , the control valves  42 ,  44 , the interne system  37 , the processor and memory  30 ,  32 , and other components may be entirely hidden from view from a location external to the mouth  62  of the dragon  60 . Certain components within the mouth  62  may be mounted onto an inner surface of the dragon  60  for positioning the system  10 . For example, the fuel source  20  of the fuel may be mounted to a component of the dragon  60 , such that the components directly and indirectly coupled (e.g., structurally coupled) to the fuel source  20  are also supported. Further, the nozzles  14 ,  16  may hang from a top of the mouth  62  of the dragon  60 , or may be propped up by a component extending upwards from a bottom of the mouth  52  of the dragon  60  to the nozzles  14 ,  16 . Further, the igniter  18  may include a pilot light  64 , where the igniter  18  (e.g., blast pilot) extends upwards (e.g., in direction  66 ) from a bottom surface just inside the mouth  62  of the dragon  60  and, upon instruction from the burner controller  41  (as described above), releases the pilot light  64 . In this way, the gaseous fuels accelerating out of the nozzles  14 ,  16  may pass over the pilot light  64  of the igniter  18  and continue out of the mouth  62  as the flame effect  17 , generally in direction  68 . In some embodiments, the flame effect  17  may measure, from the pilot light  64  in the mouth of the dragon  62  in direction  68 , between approximately 10-60 feet (3-18 meters), 20-50 feet (6-15 meters), or 30-40 feet (9-12 meters). The distance of the flame effect  17  from the mouth  52  of the dragon  60  may be at least partially determined by the flow rate of the fuels being supplied to the fuel passageways  34 ,  36  (and, thus, the flow rate of the fuels being supplied to the inner nozzle  14  and outer nozzle  16 ), among other factors, where the flow rate and said other factors are controlled via the controller  28 , as described above. 
     Turning now to  FIG. 3 , a perspective view of the nozzle assembly  12  is shown with the inner nozzle  14  and the outer nozzle  16 . The inner nozzle  14  may include a threaded portion  70  at an inlet  72  of the inner nozzle  14  for coupling the inner nozzle  14  to the corresponding control valve  42  or to a passageway (e.g., the passageway  34 ) extending between the inner nozzle  14  and the control valve  42 . The outer nozzle  14  may also include a threaded portion  74  at an inlet  76  of the outer nozzle  16  for coupling the outer nozzle  16  to the corresponding control valve  44  or to a passageway (e.g., the passageway  36 ) extending between the outer nozzle  16  and the control valve  44 . 
     In the illustrated embodiment, the inner nozzle  14  extends into a side  78  of the outer nozzle  16  and curves into a substantially concentric orientation (e.g., relative to the outer nozzle  16 ) within the outer nozzle  16 . In other words, at least an outlet  80  of the inner nozzle  14 , in the illustrated embodiment, is substantially concentric with an outlet  81  of the outer nozzle  16  about a longitudinal axis  82  extending generally in direction  68  within the nozzle assembly  12 . In another embodiment, the outlet  81  and the outlet  80  may not be substantially concentric, but the cross sectional profile of the outlets  80 ,  81  may be substantially parallel to a single plane (e.g., a plane perpendicular to direction  68 ). In other words, in some embodiments, the outlet  81  and the outlet  80  may be nested (e.g., for at least a portion) but may not be substantially concentric. For example, the outlets  80 ,  81  may be axially symmetric and/or planar symmetric. Further, in the illustrated embodiment, the outlet  80  of the inner nozzle  14  is offset from the outlet  81  of the outer nozzle  16  along the longitudinal axis  82  by an offset distance  84 . Technical effects of the substantial concentricity and offset distance  84  of the nozzle assembly  12  are described below. 
     As previously described, gaseous fuels or other fluids (e.g., non-combustible fluids or inert gases) are accelerated through both the inner nozzle  14  and the outer nozzle  16 . For example, fuel enters the outer nozzle  16  at the inlet  76  of the outer nozzle  16 . The fuel accelerates through the outer nozzle  16  and approaches an outer surface  86  of the inner nozzle  14 , which may partially disrupt the flow of the fuel (e.g., fluid) through the outer nozzle  16 . However, the outlet  80  of the inner nozzle  14  is offset the offset distance  84  from the outlet  81  of the outer nozzle  16 . Accordingly, the flow of the fuel within the outer nozzle  16  may at least partially recover and/or accelerate in the nozzle assembly  12  before exiting the outlet  81  of the outer nozzle  16 . In other words, when the flow of the fuel within the outer nozzle  16  passes over the inner nozzle  14 , the flow may be disrupted and may become more turbulent. After passing the outlet  80  of the inner nozzle  14 , the flow of the fuel from the outer nozzle  16  passing the outlet  80  of the inner nozzle  14  may partially recover (e.g., become less turbulent) due to (a) radially outward pressure against the fuel (e.g., the fuel supplied to the outer nozzle  16 ) by the flow of fuel exiting the outlet  80  of the inner nozzle  14  (e.g., the fuel supplied to the inner nozzle  14 ) and (b) radially inward pressure against the fuel (e.g., the fuel supplied to the outer nozzle  16 ) by the structure of the outer nozzle  16  itself. 
     Further, as indicated above, fluid enters the inner nozzle  14  through the inlet  72  of the inner nozzle  14  and curves into, for example, the substantially concentric portion of the inner nozzle  14  within the outer nozzle  16  or a least a portion that substantially shares a flow path direction with the outer nozzle  16 . The fuel accelerates through the inner nozzle  14  and exits at the outlet  80  of the inner nozzle  14  into a portion of the outer nozzle  16 . Accordingly, the fuel accelerating through the outer nozzle  16  may form a substantially annular layer  88  about the fuel flowing out of the inner nozzle  14  and into the outer nozzle  16 . As described above, the fuel in the annular layer  88  may at least partially recover after being disrupted by the obstacle presented by the inner nozzle  14  due to inward pressure from the outer nozzle  16  itself and outward pressure via a cylindrical flow body  90  of fuel exiting the inner nozzle  14 . In other words, the annular layer  88  may surround or envelop the substantially cylindrical flow body  90  (e.g., in volumetric terms). The cylindrical flow body  90  and the annular layer  88  may actually be warped or curvilinear due to the convergence and divergence of the outer nozzle  16 . Further, in some embodiments, the cylindrical flow body  90  and the annular layer  88  may mix fully or to a finite extent due to the configuration of the outer nozzle  16  through which the annular layer  88  flows and through which the cylindrical flow body  90  flows after exiting the inner nozzle  14 . Accordingly, it should be understand that the annular layer  88  and the cylindrical flow body  90  within the outer nozzle  16  downstream of the outlet  80  of the inner nozzle  14  may generally conform to the shape of the outer nozzle  16  downstream of the outlet  80  of the inner nozzle  14  or, in some embodiments, may mix due to the shape of the outer nozzle  16  downstream the outlet  80  of the inner nozzle  14 . Thus, it should be recognized that variations of a “annular layer” and/or “cylindrical flow body” geometry (e.g., relative to the flow of the fluids through the nozzle assembly  12 ) may occur, but that said terms “annular layer” and/or “cylindrical flow body” are indicative of the general shape of the flow of fluid in one embodiment coming from the outer nozzle  16  and the inner nozzle  14 , respectively. The various embodiments pertaining to the configuration of and effect of fluid flowing through the nozzles  14 ,  16  will be discussed in greater detail below. 
     Continuing with the illustrated embodiment, the annular layer  88  may include a first type of fuel (or other fluid) and the cylindrical flow body  90  may include a second, different type of fuel (or other fluid), as previously described. It should be noted that the fluid flowing through the outer nozzle  16  before reaching the inner nozzle  14  at the point where the inner nozzle  14  enters the outer nozzle  16  may actually flow through the entirety of the outer nozzle  16  and, thus, would not be an “annular film” until the inner nozzle  14  intersects into the outer nozzle  16 . The fuel or fluid that makes up the annular layer  88  and the fuel or fluid that makes up the cylindrical flow body  90  may be determined based on environmental factors, as previously described, measured by the sensor  38  and relayed through the processor  30  to instruct the automation controller  28  to, for example, adjust fuel sources  22  and  24  and control valves  42  and  44  accordingly (e.g., as illustrated in  FIGS. 1 and 2 ). For example, in one embodiment, the annular layer  88  (e.g., of the outer nozzle  16 ) includes propane, which generally burns more visibly in daylight than other combustible fuels (e.g., natural gas). The cylindrical flow body  90  (e.g., originating in the inner nozzle  14 ), for example, may include natural gas, which generally burns less visibly during daylight but is cleaner and less expensive than other combustible fuels (e.g., propane). In this way, on a bright day, the flame effect  17  produced by the nozzle assembly  12  may include a clearly visible, burning annular layer  88  around a cleaner burning, less expensive, cylindrical flow body  90 . In another embodiment, the annular layer  88  and the cylindrical flow body  90  may actually mix within the outer nozzle  16  downstream the outlet  80  of the inner nozzle  14 . Accordingly, the flame effect  17  may be bright and clean burning, but may not necessarily include a bright burning outer layer (e.g., sheath) and a clean burning inner portion, but may rather be substantially mixed such the entire flame effect  17  is bright and colorful while also maintaining cleanliness. 
     In another embodiment, the annular layer  88  may include the natural gas and the cylindrical flow body  90  may include the propane, which results in a clearly visible burning cylindrical flow body  90  and a cleaner burning, less expensive, annular layer  88 . Alternatively, the two portions of fluids may mix thoroughly, as described above. Further, in any of the embodiments described above, natural gas is generally more buoyant than propane, which may enable the cleaner burning natural gas to “carry” the combusted or burned propane pollutants a distance such that the propane pollutants may be distributed and/or dissipated over the distance as it mixes with air, as opposed to the propane pollutant being concentrated (e.g., deposited) in a particular area. As previously described, the type of fuel chosen for each nozzle  14 ,  16 , may be instructed via the automation controller  28  based on environmental factors measured by, and relayed from, the sensor  38  and/or the Internet system  37 . Further, respective pressures (and, thus, respective flow rates) of the fuel in the annular layers  88  and the fuel in the cylindrical flow body  90  may be enabled via instruction of the automation controller  28 , as previously described, to optimize the flame effect  17  based on the computer program executed by the processor  30 . 
     Turning now to  FIG. 4 , an embodiment of the nozzle assembly  12  is illustrated in a cross-sectional side view. Specifically, in the embodiment illustrated by  FIG. 4 , the nozzles  14 ,  16  are Laval nozzles. In the illustrated embodiment, the inner nozzle  14  enters into the side  78  of the outer nozzle  16  at an angle  100 , where the angle  100  is measured between a longitudinal axis  102  of an entry portion  104  of the inner nozzle  14  and the longitudinal axis  82  of the nozzle assembly  12 . The angle  100  may be between approximately 20 and 70 degrees, 30 and 60 degrees, 40 and 50 degrees, or 43 and 47 degrees. The angle  100  may be determined during design based on a number of factors. For example, the angle  100  may be obtuse to enable a better flow through the inner nozzle  14 . In other words, with an obtuse angle  100 , the inner nozzle  14  includes a more gradual curve  102  within the outer nozzle  16 , which may enable improved flow through the inner nozzle  14 . However, by including the obtuse angle  100 , the entry portion  104  of the inner nozzle  14  may be longer and present a larger obstacle for the flow within the outer nozzle  16  to overcome. Alternatively, with an acute angle  100 , the entry portion  104  is shorter and presents a smaller obstacle for the flow within the outer nozzle  16  to overcome, but the flow within the inner nozzle  14  may experience increased turbulent flow due to the abrupt directional flow change. Further, the offset distance  84  may affect the optimal angle  100 , because with a greater offset distance  84 , the annular film  88  has a greater distance to recover from the flow obstacle presented by the entry portion  104  of the inner nozzle  14 . Thus, in some embodiments, the offset distance  84  may be longer and the angle  100  more acute, which enables improved flow through the inner nozzle  14  and a greater distance for the flow through the outer nozzle  16  (e.g., the annular film  88 ) to recover. 
     Continuing with  FIG. 4 , both the inner nozzle  14  and the outer nozzle  16 , as previously described, converge in one portion and diverge in another portion. For example, the inner nozzle  14  includes a converging portion  106  and a diverging portion  108  and the outer nozzle  16  includes a converging portion  110  and a diverging portion  112 . Between the converging and diverging portions  106 ,  108  of the inner nozzle  14  is a throat  114  of the inner nozzle  14 . Between the converging and diverging portions  110 ,  112  of the outer nozzle  16  is a throat  116  of the outer nozzle  16 . In the illustrated embodiment, the outlet  80  of the inner nozzle  14  is disposed adjacent the beginning of the converging portion  110  of the outer nozzle  16 . In other words, in some embodiments, the offset distance  84  may substantially correspond with a length of the converging portion  110  and the diverging portion  112  of the outer nozzle combined. This may enable at least partial recovery of the annular layer  88  in the outer nozzle  16  within the converging and diverging portions  110 ,  112  of the outer nozzle  16 . Alternatively, in some embodiments, this may provide a larger distance within the outer nozzle  16  (e.g., measured from the outlet  80  of the inner nozzle  14  to the outlet  81  of the outer nozzle  16 ) through which the gases (e.g., the annular layer  88  and the cylindrical flow body  90 ) may mix. 
     An embodiment of the nozzle assembly  12  is shown in a front view illustration in  FIG. 5 . In the illustrated embodiment, the outlet  80  of the inner nozzle  14  is substantially concentric with the outlet  81  of the outer nozzle  16  about the longitudinal axis  82 . During operation, the annular layer  88  will be between the outer nozzle  16  and the inner nozzle  14 , and the cylindrical flow body  90  exits the inner nozzle  14  and includes a cross-section within the outer nozzle  16  substantially equal to the cross-section of the outlet  80  of the inner nozzle  14 . However, it should be noted that cross sections of the annular layer  88  and the cylindrical flow body  90  taken at one point within the outer nozzle  16  along the longitudinal axis  82  may not be exactly the same as cross sections of the annular layer  88  and the cylindrical flow body  90 , respectively, at another point within the outer nozzle  16  along the longitudinal axis  82 . Differences between the cross-sections may occur due to the convergence and divergence of the outer nozzle  16 , which decreases and increases the cross-sectional area, respectively, of the outer nozzle  16 . Differences between the cross-sections may also occur due to the inner nozzle  14  interrupting flow in the outer nozzle  16  downstream the converging and diverging portions  110 ,  112  (as shown in  FIG. 4 ) of the outer nozzle  16 . Further, as described above, the annular layer  88  and the cylindrical flow body  90  may mix in some embodiments due to the contour of the outer nozzle  16  downstream the inlet  80  of the inner nozzle  14 . 
     Although embodiments of the nozzle assembly  12  described above include the inner nozzle  14  and the outer nozzle  16 , some embodiments may include more than two nozzles. For example, an embodiment of the nozzle assembly  12  having three nozzles is illustrated in a cross-sectional side view in  FIG. 6  and a front view in  FIG. 7 . In the illustrated embodiments, the inner nozzle  14  and the outer nozzle  16  are both disposed within a third nozzle  120 . The inner nozzle  14  may enter into a side  122  of the third nozzle  120  in the same way the inner nozzle enters the side  78  of the outer nozzle  16 . The outer nozzle  120  may be coupled to the same fuel source (e.g., the fuel source  20 ) as the inner nozzle  14  and the outer nozzle  16 . In the illustrated embodiment, each nozzle  14 ,  16 ,  120  may include a different type of fuel. For example, the inner nozzle  14  may include natural gas, the outer nozzle  16  may include propane, and the third nozzle  120  may include nitrogen, which may serve to “carry” pollutants from, for example, burned propane a distance from the nozzle assembly  12  after exiting the nozzle assembly  12 , as similarly described above with reference to the natural gas. In this way, the fuel exiting an outlet  124  of the third nozzle  120  (e.g., after passing through a converging portion  126  and diverging portion  128  of the third nozzle  120 ) may include the cylindrical flow body  90 , the annular layer  88 , and a second annular layer  130  radially adjacent to and surrounding the annular film  88 . As previously described, the cylindrical flow body  90 , the annular layer  88 , and the second annular layer  130  may each include a different type of fuel relative to one another. For example, the cylindrical flow body  90  may include natural gas, the annular layer  88  may include propane, and the second annular layer  130  may include nitrogen. In another embodiment, the cylindrical flow body  90  may include nitrogen, the annular layer  88  may include natural gas, and the second annular layer  130  may include propane. Any fuel or fluid may be used for any of the three nozzles depending on the desired flame effect  17 . 
     It should be noted that while certain embodiments of the nozzles are illustrated as including converging-diverging nozzles, in other embodiments variations of the nozzle types might be employed. For example, some may be simply converging or include substantially consistent (parallel) walls. In  FIG. 8 , an embodiment of the nozzle assembly  12  is shown having the inner nozzle  14  and the outer nozzle  16 , where the inner nozzle  14  and the outer nozzle  16  are converging nozzles. In other words, the inner nozzle  14  includes the converging portion  106  and the outer nozzle  16  includes the converging portion  110 . Neither nozzle  14 ,  16 , in the illustrated embodiment, includes a diverging portion. The converging portions  106 ,  110  may accelerate fuel through each respective nozzle  14 ,  16 , and the fuels exit the nozzle assembly  12  through the outlet  81  of the outer nozzle  16 . In  FIG. 9 , an embodiment of the nozzle assembly  12  is shown having the inner nozzle  14  and the outer nozzle  16 , where the inner nozzle  14  and the outer nozzle  16  are substantially consistent (parallel) straight walled nozzles. In other words, an inner portion  140  of the inner nozzle  14  is substantially cylindrical, where an inner surface  142  of the inner portion  140  of the inner nozzle  14  extends substantially in direction  68 , parallel with the longitudinal axis  90 . Additionally, an inner portion  144  of the outer nozzle  16  is substantially cylindrical, where an inner surface  146  of the inner portion  144  of the outer nozzle  16  extends substantially in direction  68 , parallel with the longitudinal axis  90 . In general, the contours of the various nozzles  14 ,  16 , as well as the offset or offsets (e.g., offset distance  84 ) between the outlets  80 ,  81  of the nozzles  14 ,  16 , respectively, may be selected depending on the desired flame effect  17 . For example, if the desired flame effect  17  requires that the gases from the inner nozzle  14  and the outer nozzle  16  mix within the nozzle assembly  12 , appropriate contours of the inner and outer nozzles  16  and an appropriate offset distance  84  may be selected accordingly. If the desired flame effect  17  requires that the gases from the inner nozzle  14  and the outer nozzle  16  remain separate (e.g., by maintaining substantially the annular film  88  and cylindrical body flow  90  through the nozzle assembly  12 ), the appropriate contours of the inner and outer nozzles  16  and the offset distance  84  may be selected accordingly. 
     It should also be noted that, in other embodiments, the fluid passageways of the nozzles may be coupled together or attached in some other manner. One such embodiment is illustrated in  FIG. 10 , which is a cross-sectional representation of the inner and outer nozzles  14 ,  16  in a particular geometry. In the illustrated embodiment, one or more fuel passageways (e.g., passageways  146 ), which are coupled to the fuel source  20  (not shown), may each carry a different type of fuel or fluid to the outer nozzle  16 . Or, each of the passageways  146  may carry the same fuel or fluid to the outer nozzle  16 . In the illustrated embodiment, an inner passageway  147  is coupled to the inner nozzle  14 , and supplies fuel or fluid from the fuel source  20  (not shown) to the inner nozzle  14 . The nozzle assembly  12  may then pass the fuels through each of the nozzles  14 ,  16  such that the fuels exit at the outlet  81  of the outer nozzle  16  and pass over the pilot light  64  of the igniter  18  for generating the flame effect  17 .  FIG. 11  shows a perspective cross-sectional view of inner and outer nozzles  14 ,  16  with similar features. 
     Other embodiments may also exist. For example, in one embodiment, the nozzle assembly  12  may only include a single nozzle, where a fuel or fluid passageway is coupled to the back of the nozzle and a series of smaller fuel passageways may enter into a sidewall of the nozzle and terminate at the sidewall. As such, fuel or fluid passing through the smaller fuel passageways may inject directly into the nozzle from the sidewall into the stream of the fuel or fluid being routed through the nozzle from the back of the nozzle. 
     As described above, any combustible or non combustible gas may be used for any one of the nozzles  14 ,  16 ,  120  described heretofore, and said combustible or non combustible gas selected for each nozzle  14 ,  16 ,  120  from the fuel source may be determined based on measurements taken by the sensor  38  or provided to the processor  30  by the Internet system  37  relating to environmental factors. The particular type of gas (e.g., fuel) accelerated through each nozzle  14 ,  16 ,  120  may include desirable characteristics based on the measurements taken by or provided by the sensor  36  and/or Internet systems  38 ,  40 . For example, as previously described, propane may be selected for one of the nozzles  14 ,  16 ,  120  to provide a visible flame effect  17  that can be seen during daylight. Natural gas may be selected for one of the nozzles  14 ,  16 ,  120  for cleanliness and/or cost related concerns. In particular, natural gas may be selected at night, because burning natural gas is generally visible in the dark and is more cost-effective and clean than propane, which is generally visible during the day and night. Additionally, as previously described, a mass flow rate (and, thus pressure) of any one of the fuels traveling through any one of the nozzles  14 ,  16 ,  120  may be increased or decreased via action resulting from output from controller  28  to one or more system actuators (e.g., control valves). 
     It should be noted that certain elements in the previously illustrated embodiments may include some variations not already described. For example, a schematic diagram is shown in  FIG. 12  to provide a basic illustration of the system  10  and the nozzle assembly  12 . In the illustrated embodiment, a number of configurations  148  of the nozzle assembly  12  are shown having nested nozzles with respective gas flow paths indicated by arrows  149 . In some embodiments, as indicated by a first configuration  150 , two nozzles may be in a substantially concentric orientation  150  and an exit of the outer nozzle may be farther along the gas flow path  149  than the exit of the inner nozzle. In other embodiments, as generally represented by a second orientation  152 , three or more nozzles may be in a substantially concentric orientation and each respective nozzle from the second innermost to the outermost may have an exit that extends farther along the gas flow path  149  than that of the nozzle or nozzles nested therein. In still other embodiments, as generally represented by a third orientation  154 , a number of nozzles may be nested within one another and certain nozzles may have exits that are aligned. In yet other embodiments, nozzles that are nested within a nozzle may have an exit that extends further along the gas flow path  149  than the nozzle in which they are nested. In accordance with the present disclosure, any orientation and number of nested nozzles may be used for the nozzle assembly  12 . 
     In some embodiments, each nozzle may include converging and diverging portions, as previously discussed, to facilitate acceleration of the hot gasses passing through the particular nozzle. However, other embodiments may include nozzles with only a converging portion, only a diverging portion, only a straight walled (e.g., substantially cylindrical) portion, or some other combination of the described portions. Also, while there is an offset between outlets of nested nozzles in the illustrated embodiments, in some embodiments, nozzle outlets may be substantially aligned. For example, two inner nozzles may have aligned outlets but remain offset relative to an outermost nozzle that has an outlet extending past the outlet of the innermost nozzles. 
     Further, the nozzles may be configured to receive inserts, such that an insert may be manually inserted into either of the nozzles to redefine the nozzles. For example, a nozzle with a converging portion and a diverging portion may, based on the desired flame effect  17 , receive an insert with only a converging portion to temporarily redefine the nozzle as a nozzle with only a converging portion. The nozzle with the insert may be utilized until it is determined that the desired flame effect  17  may benefit from a nozzle with both a converging and diverging, at which point the insert may be removed. It should be noted that the initial configuration of the nozzle may include only a converging portion or both a converging and diverging portion, and that the insert may include only a converging portion or both a converging and diverging portion. Further, the insert may include the same types of portions (e.g., converging and/or diverging) as the initial nozzle, but the dimensions (e.g., cross-sectional area, slope) of the various portions may be different for the insert and may enhance the flame effect  17  in some way in certain conditions (e.g., based on environmental factors). Further still, the initial nozzle, the insert, or both may include a straight walled (e.g., substantially cylindrical) portion, as previously described. Also, various different nozzles and/or nozzle inserts may be provided as nozzle banks that can be alternated in and out of use by redirecting fuel flow or maneuvering the bank of nozzles. In other words, the different nozzles and/or nozzle inserts may be automatically placed into the nozzle assembly  12  via regulation by the automation controller  28 , which may determine the appropriate nozzle and/or insert based on environmental factors received by the automation controller  28  in addition to determining the appropriate fuel source for each nozzle and the appropriate pressure for each fuel source, as previously described. In some embodiments, multiple controllers may be used, where each controller controls one or more of the components described above, and each controller may receive instructions for the same or different processors, where each processor receives measurements from the same or different sensors and/or Internet systems. 
     Continuing with  FIG. 12 , the automation controller  28  may include or be coupled to one or more inputs  156 . The inputs  156  may include measurements of the environmental factors measured by the sensor  38  and values of the environmental factors provided as provided by the Internet system  37 . The environmental factors may include environmental brightness, flame brightness, environmental pollution, flame soot levels, weather, wind conditions, time of day, and/or humidity. Further, the inputs  156  may be analog and/or digital inputs. 
     The automation controller  28  may also include or be coupled to one or more actuators  158 , where the automated controller  28  provides instructions to the actuators  158  for regulating the actuators  158 . The actuators  158  may include valves, regulators, pumps, igniters, or other features for actuating various features of the system  10 . The actuators  158  may include actuators  158  upstream of the nozzle assembly  12  and actuators  158  downstream of the nozzle assembly  12 . For example, upstream of the nozzle assembly  12 , the actuators  158  may include a rotator configured to rotate the fuel source  20  about a bearing, where the bearing is physically coupled to two or more fuel tanks of the fuel source  20 . By rotating the fuel source  20  about the bearing, one of the two or more fuel tanks of the fuel source  20  may be fluidly coupled to a conduit leading to one of the nozzles. In other embodiments, a different type of actuator  158  may be used to couple the appropriate fuel type to the appropriate nozzle. Further, upstream of the nozzle assembly  12 , the actuators  158  may include a regulatory device for regulating pressures (e.g., supply pressures) of the fuel types as they are delivered to the appropriate nozzles. For example, the actuators  158  may include a pump configured to pump fuel to the nozzles at a certain pressure. Other actuators  158  may be included for actuating other portions of the system  10  upstream the nozzle assembly  12 , in accordance with the present disclosure. 
     Downstream of the nozzle assembly  12 , one of the actuators  158  may be a fan configured to blow upwardly and/or at an angle on the flame effect  17 , such that the soot generated by the flame effect  17  is blown away from the system  10  and dispersed over a distance as opposed to concentrated in one place near the system  10 . In some embodiments, the ignition feature  18  may be considered as one of the actuators  158 , and the automation controller  28  may control the ignition feature  18  to determine when to use the ignition feature  18 . For example, in one embodiment, the ignition feature  18  is a flame, where the fuels passing through the nozzle assembly  12  pass over the flame. The automation controller  28  may control when the ignition feature  18  has a lit flame and when the ignition feature  18  does not have a lit flame. Further, one of the actuators  158  downstream the nozzle assembly  12  may include a rotator configured to rotate a bank of nozzles or nozzle inserts about a bearing, such that the appropriate nozzle or nozzle insert may be placed into the nozzle assembly  12 , as previously described. Other actuators  158  may be included for actuating other portions of the system  10  downstream the nozzle assembly  12 , in accordance with the present disclosure. 
     Turning now to  FIG. 13 , a process flow diagram illustrating a method  160  of operating the system  10  is shown. The method  160  includes determining (block  162 ) environmental factors around the nozzle assembly  12 . As previously described, determining environmental factors around the nozzle assembly  12  may include measuring the environmental factors via the sensor  38  and providing the measurements to the automation controller  28 . Further, the Internet system  37  may be used to provide values of the environmental factors to the automation controller  28 . The method  160  also includes fluidly coupling (block  164 ) an appropriate fuel type or types from the fuel source  20  with each of the inner nozzle  14  and the outer nozzle  16 , based on the environmental factors received by the automation controller  28 . Further, the method  160  includes accelerating or passing (block  166 ) the fuel through the nozzles  14 ,  16  of the nozzle assembly  12  at appropriate respective pressures, which are determined and regulated by the automation controller  28  (e.g., via automated control of control valves, regulators, pumps) based on the environmental factors. Further still, the method  160  includes passing (block  168 ) the fuel over the ignition feature  18  (e.g., the flame) to generate the flame effect  17 . 
     While only certain features have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the disclosure.