Automatic temperature and humidity regulation – Distance-adjusted
Reexamination Certificate
2001-08-06
2004-04-27
Wayner, William (Department: 3744)
Automatic temperature and humidity regulation
Distance-adjusted
C236S049300, C062S175000
Reexamination Certificate
active
06726111
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to air control systems. More specifically, the present invention relates to a system capable of maintaining constant environmental characteristics in more than one air control system through the use of a single controller that receives and processes detailed input from each of the air control systems and interfaced appliances.
BACKGROUND OF THE INVENTION
The need for air control systems first became apparent in the 16
th
century with the advent of chimneys in Europe. Despite improvements since then, most chimneys still operate on a natural draft system. A natural draft chimney operates by force of gravity. That is, the hot flue gases in the chimney are lighter than the surrounding ambient air. Being lighter, flue gases are displaced by cooler, heavier air and rise buoyantly through the chimney flue creating a natural draft.
This natural drafting is affected by a host of environmental factors. Ambient air temperature and atmospheric pressure affect the density of the ambient air mass. If the density of the ambient air mass is reduced, the efficiency of the natural drafting is reduced as well. For example, wind can either increase draft by blowing across the intake portion of a naturally drafting system creating a venturi effect, or reduce draft if turbulent. In addition, wind can cause a back draft, a reverse flow through a system. In the case of a chimney, this can cause flue gases to be vented within a building.
Over the years, systems have been developed where appliances are designed to operate in modular or modulated fashion. Boilers, heaters, water heaters, and other appliances operate in groups. Each unit may fire or power up at different times in response to specific demands. As a result of this modular configuration, the demand upon the pressure, temperature, and the like, within the enclosed building can vary greatly depending on the operation of these appliances.
These factors create the potential for insufficient draft and overdraft which may cause undesirable, and even unsafe conditions within the enclosed air system. In addition, failure to control the quality of air within an enclosed environment, or the flues connected to the appliances for exhausting air, may drastically impede the efficiency and general operation of the appliances since an appliance or group of appliances require specific air flow rates for optimal performance.
With regard to draft systems, power venting systems have increased in popularity. The conventional power draft systems fall into two basic classes. The traditional mechanical draft system is a so-called constant volume system in which a fan provides a constant volume gas flow through a flue to carry exhaust gases to the exterior. Likewise, the mechanical draft system could also be set up to provide an intake air flow for bringing air into an enclosed environment or air system. This constant flow of air thorough an air system is inefficient and costly. Three to five thousand cubic feet per minute of air may be expelled by these systems causing loss of heat in the winter and loss of cooled air in the summer. In the case of intake flows, the mechanically drawn air brought into an air system could provide an undesirable pressure within the system. In addition, this inflexible flow of air in or out of the air system can again impede the efficiency and general operation of any appliances.
In recent years, power venting systems have been implemented in HVAC, kitchen, and other systems to deal with the inherent drawbacks of a mechanical draft system. Namely, controller devices have been advanced which connect to intake and outtake fans for controlling air system characteristics in a single system. Generally, these systems are most often utilized in detecting and controlling the pressure characteristic within a vent flue. Two sensors are placed within the venting system to sense pressure changes. These sensors are in communication with one electronic controller for processing data and controlling input and output devices, such as the sensors and fan. Typically, these two switch sensors are used with one sensor defining the low pressure point and the other defining the high pressure point. Each pressure setting is defined by inputted parameters. These two pressure points define a window of acceptable pressure within the venting flue. If the pressure in the flue falls outside this window, the relevant sensor is triggered and provides a closed circuit for sending a signal to power the fan up or down, depending on which sensor is triggered. In such a system, the fan adjusts the pressure by fully powering up or down, or in the alternative, by switching to predetermined limited speeds such as high, medium, low, or some other variation. While an improvement over more traditional mechanical draft systems, this method of adjustment is costly and inefficient, and fails to make the precise system-wide adjustments needed to maintain a truly “continuous” pressure system. While such systems may be referred to as “constant” pressure systems, such a designation is not a true characterization of their operation.
The innate drawback of such an “on-off” air control system is that it is incapable of providing and maintaining a constant pressure within the system. The pressure window may be so large as to permit a great range of pressure deviation before any adjustments are made by the turning on of a fan. Similarly, if the pressure window is made small in an attempt to maintain pressure, the fan is frequently turned on and off to adjust for fluctuations in pressure. On-off switches and non-variable fan motors may continuously jump through pressure levels in an attempt to maintain pressure, but they are incapable of keeping pressure at precise levels, especially when an air system is dynamically effected by the demands of multiple appliances and changing environmental factors such as wind.
Even those systems that have attempted to implement a single sensor to measure and maintain a characteristic such as pressure do so using these “on-off” techniques, and inevitably jump the fan speed to predetermined and limited levels. In addition, conventional systems fail to maximize the efficiency and effectiveness, and reduce the cost, associated with controlling their systems since they implement an independent controller for each system, and fail to arm the controllers they do use with effective appliance interfacing and adaptive technology.
Those conventional systems attempting to monitor and maintain an environmental characteristic, unfortunately, do assign one controller to each air control system. For example, one controller would receive sensor input and provide control over a venting system, and a separate controller would be assigned to a combustion intake system. Consequently, repetitive circuitry and control structures are required for each system, even when numerous air systems (i.e., venting, combustion, and heating) are contained within one building. This presents a significant cost problem, as well as a training and standardization problem. The cost problem is significant at the production level, and at the purchasing level. A purchaser would obviously prefer not to expend monies on a controller for each individual air control system contained within a particular enclosed environment. In addition, the training and standardization problem likely increases over time. As time passes, it is quite possible that vastly different controllers will be purchased and implemented for the different air control systems within one enclosed environment. Each controller will operate differently, varying in operating parameters, inputting methods, and other functions. Training, usage, and maintenance costs will also increase with the employment of an individual controller at each air control system. The standardization benefits and cost savings would be substantial if only one controller was used to monitor and control a plurality of air control systems.
In addition, the conventional wisdom is to collectively deal with applian
Hoyez Timothy G.
Weimer John R.
Patterson Thuente Skaar & Christensen P.A.
Tjernlund Products, Inc.
Wayner William
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