Abstract:
A crawl space ventilation system includes an intake fan assemby (10) having a housing with an 8×15 inch tubular mounting portion (b 16), a jet-stream directing portion (30) which is substantially smaller than the mounting portion, and an electric fan mounted in the housing for driving air toward the jet-stream directing portion. The mounting portion is mounted in a crawl-space vent hole with the jet portion directed into the crawl-space toward a particular area to be ventilated. The crawl-space ventilation system also includes an outlet fan assembly (44) with an approximately 8×15 inch housing (46) and a jet-catching end (51). The outlet fan assembly also is mounted in a crawl space vent and is positioned to capture the air jet driven into the crawl space by the inlet fan assembly. Intermediate booster fan assemblies (70, 72) are also included to be mounted in the crawl space between vents for capturing and transmitting the jet stream between the inlet and outlet fan assemblies. Humidistats control the various fan assemblies.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to ventilation systems for crawl spaces under houses and more specifically to such ventilation systems for preventing rot and corrosion due to moisture. 
     Many house, especially those in areas with high water tables, are built with crawl spaces thereunder. Nicer homes, such as brick homes, as well as other homes, often have walls extending to the ground around the crawl spaces for aesthetic purposes. A difficulty with crawl spaces which are thusly walled in is that they create a stagnant environment therein which is often filled with moist air. This moist air tends to cause mold, mildew, rot and general corrosion under a house. To avoid such corrosion most builders install 8×15 inch side vents in the house walls about the crawl spaces. These vents allow air to pass through the crawl spaces, thereby reducing the stagnation therein, and periodically flushing out moist air. However, such vents tend to create air flows along certain lines only, still leaving pockets of stagnant, moist, air where rotting and corrosion takes place. It is an object of this invention to provide a crawl-space ventilation system which does not leave undesirable pockets of stagnant air in that it allows one to target such pockets for eradication. 
     It is a further object of this invention to provide a ventilation system for a house crawl space which can be relatively easily installed without damaging or changing the house. 
     Further still, it is an object of this invention to provide such a ventilation system which is relatively inexpensive to manufacture, install and operate, but yet is extremely effective in eliminating rotting in the crawl space of a house. 
     SUMMARY 
     According to principles of this invention, a house crawl space ventilation system includes an inlet fan assembly having a tubular housing with an 8×15 inch mounting portion and a jet-creating portion with an electric fan mounted therein. The inlet fan assembly is mounted in an 8×15 inch ventilation hole of a house crawl space with the jet portion pointing into the crawl space and directing an air jet toward a stagnant space therein to ventilate the space. The ventilation system also includes an outlet fan assembly having a tubular housing with an 8×15 inch housing and a jet-catching end with an electric fan therein for receiving the jet ventilation stream created by the inlet fan assembly and exhausting it from the crawl space. The ventilation system also includes intermediate booster fan assemblies having tubular housings with jet catching ends and jet-creating ends for being positioned intermediate the inlet and outlet fan assemblies. A system of humidistats located at stagnant areas to be ventilated controls power to the fan assemblies simultaneously. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of a preferred embodiment of the invention, as illustrated in the accompanying drawings in which reference characters refer to the same parts throughout the different views 
     The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the invention in a clear manner. 
     FIG. 1 is an isometric view of an inlet fan assembly of the crawl-space ventilation system of this invention; 
     FIG. 2 is a top view of the inlet fan assembly of FIG. 1 with an additional aiming member mounted thereon; 
     FIG. 3 is a cross-sectional view taken on line 3--3 in FIG. 2; 
     FIG. 4 is a side, partially cutaway, view of the inlet fan assembly of FIG. 1; 
     FIG. 5 is a front view of the inlet fan assembly of FIG. 1; 
     FIG. 6 is a top view of a jet-creating portion of the fan assembly of FIG. 2; 
     FIG. 7 is a top view of a mounting portion of the fan assembly of FIG. 1; 
     FIG. 8 is an isometric, and partially schematic, view of a crawl space having a crawl-space jet ventilation system of this invention mounted therein; 
     FIG. 9 is an isometric, partially-cutaway, view of an exhaust-fan assembly of the ventilation system of FIG. 8; 
     FIG. 10 is a top, partially-segmented, view of the exhaust-fan assembly of FIG. 9 mounted in a crawl space ventilation hole; 
     FIG. 11 is an inner-end view of the exhaust fan assembly of FIGS. 9 and 10; and 
     FIG. 12 is a top view of an intermediate-fan assembly of this invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An inlet fan assembly 10 for a crawl space jet ventilation system of this invention, as shown in FIG. 1, comprises a housing 12 and an electric motor driven fan 14 (FIGS. 3 and 4). The housing 12 comprises a vent-mounting portion 16 and a jet-creating portion 18, and each of these elements is respectively depicted separately in FIGS. 6 and 7. The housing-mounting portion 16 comprises mainly an 8×15 inch rectangular tube 20 with a flange 22 and louver slats 24 mounted at an outer mouth 25 thereof. The rectangular tube 20 can be constructed of metal, however, in the preferred embodiment, it is constructed of a hard, flame resistant, plastic. The flange 22 extends outwardly from an outer surface 26 of the rectangular tube 20 and its rear surface 22a is designed to abut against the front surface of a house when the housing mounting portion 16 is mounted in a crawl space vent opening. The louver slats 24 are hung on pivots located at opposite ends thereof near the top edges so that an inward air flow from outside atmosphere into the rectangular tube 20 through the louver slats tends to open them automatically, but when there is no wind their weight closes them. 
     The jet-creating portion 18 comprises an inwardly tapered portion 28 and a jet-stream directing portion 30. The inwardly tapered portion 28, as can be seen by comparing FIGS. 2 and 4 tapers inwardly at the sides, but the height dimension, between the top and bottom, remains a constant 8 inches. Again, the jet-creating portion can be made of a metal or a hard, flame-resistant, plastic. 
     The electric fan 14 is mounted in the round jet-stream directing portion 30 of the housing 12. In this respect, the jet-stream directing portion 30 has a diameter of 8 inches and blades 32 of the electric fan 14 extend from a motor 34 almost to the wall of the jet-stream directing portion 30. When the fan 14 is energized via a switch 36 it rotates in a direction to suck air through the louvers, thereby opening the louvers, and to drive this air out of an end 38 of the jet-stream directing portion 30. 
     In the preferred embodiment, the jet-creating portion 18 with its inwardly tapered portion 28 and its jet-stream directing portion 30 is separate from the housing-mounting portion 16, these elements being fitted together by a female tab 40 (FIG. 6) on the jet-creating portion 18. Although the female tab 40 maybe held to the rectangular tube 20 by means of friction between an inner surface of the rectangular tube 20 and an outer surface of the female tab 40, if necessary, fasteners, such as screws, could be driven between these two members to ensure that they stay together. 
     In FIG. 2 is shown an adjunct jet-stream directing, or aiming, member 42 which can be manually maneuvered to direct a stream of air exiting from the end 38 of the jet-stream directing portion 30 in a particular direction. In this regard, the jet-stream aiming member 42 is a corrugated tube of a type used for clothes dryers and the like which can be snapped into any desired position for directing air in a desired direction. 
     Looking next at an outlet exhaust fan assembly 44 of this invention which is depicted in FIG. 9, this assembly includes a housing 46 having baffles 47 and an electric fan 38 mounted therein. The housing 46 has an approximately 8×15 inch rectangular outer surface 49 and a flange 52 at an outer end thereof directed away from the outer surface 49 of the housing 46. A jet-catching end portion 50 includes baffles 47a which guide air entering the jet-catching end 51 to the fan 48. The fan 48 has a diameter of almost 8 inches. The housing 46 is approximately 12 inches long. The outlet exhaust fan assembly 44 is mounted in a standard crawl-space 8×15 inch vent 53 by inserting it therein through the vent from the outside of a house 54 until the flange 52 contacts the outer surface of the house 54. The flange 52 can be positively attached to the house to hold it in the vent hole. 
     FIG. 8 depicts an overall crawl-space jet-ventilation system of this invention in which are shown an inlet fan assembly 10 and an outlet exhaust fan assembly 44, both mounted in 8×15 inch vents 53 defined by house walls 66 enclosing a crawl space 68. Also disclosed in FIG. 8 are intermediate booster fan assemblies 70 and 72, each of which includes an 8 inch diameter tube having a jet catching end 74 and a jet exhausting end 76. Electric fans 78 (FIG. 12) in the intermediate fan assemblies 70 and 72 catch the ventilation jet streams from upstream fan assemblies and drive them through the 8 inch exhausting ends 76. The jet-exhausting ends 76 blow these jet-streams to the next fan assemblies. 
     Also depicted schematically in FIG. 8 is an electrical energizing circuit which includes an energy source 82 (house current), a rain switch 84 controlled by a rain monitor 86, and humidity switches 88 controlled by humidistats 90. 
     The rain switch 84 and the humidity switches 88 are connected in series between the energy source 82 and the fan assemblies while the humidity switches 88 and the fan assemblies are connected in parallel with each other. In this respect, the rain switch 84 provides power to the upstream sides of all of the humidity switches 88 and all of the downstream ends of the humidity switches 88 are connected to all of the fan assemblies, 10, 44, 70, and 72. Thus, when the rain switch 84 is opened, the system is deactivated and cannot be activated by the humidity switches 88. However, when the rain switch 84 is in a closed position, any one of the humidity switches 88 can operate all of the fan assemblies 10, 44, 70 and 72 simultaneously. The rain switch 84 is automatically placed in a closed position when the monitor 86, which is positioned outside house wall 66, determines that it is not raining and is automatically placed in an open position when the rain monitor 86 determines that it is raining. Humidity switches 88 are each automatically placed in an open position when its corresponding humidistat 90 detects humidity below a set level and in a closed position when the humidity is above a set level. 
     FIG. 12 depicts the intermediate fan assembly 70 in more detail, showing that the fan 80 is mounted in an elbow portion 94 thereof. Straight portions 96 can be selectively coupled to the elbow portion 94 and to each other, by interlocking the ends together. With such a construction the intermediate fan assemblies 70, 72 and others can be assembled to be various shapes and lengths. 
     Describing now operation of the crawl-space jet- ventilation system of this invention, before the system is installed it is determined where in a crawl space stagnant air pockets exist. This can be determined by moisture meters or, over a period of time, by watching the deterioration of wood located in the crawl space. In areas where wood appears to be corroding or rotting, one ca assume the air is stagnant and that its humidity is too high. Further, those with experience in ventilating crawl spaces can estimate where stagnant-air locations are. Thereafter, vent holes in the house wall 66 are chosen for mounting the inlet fan assembly 10 and the outlet exhaust fan assembly 44 for creating a jet of air passing through the stagnant air locations. In this regard, it might be possible to locate the inlet fan assembly 10 directly across from the outlet fan assembly 44 so that the jet-creating portion 18 of the inlet fan assembly 10 blows a jet-stream directly into the jet-catching ends 51 of the outlet exhaust fan assembly 44. When this is possible, no intermediated booster fan assemblies are required. However, it might also be necessary to use intermediate fan assemblies 70 and 72 for catching the jet-stream exhausting from the jet-creating portion 18 of the inlet fan assembly 10 with the jet-catching end 74 of the intermediate fan assembly 70 and further directing it into the intermediate fan assembly 72. The intermediate fan assembly 72 boosts and refocuses the jet-stream and directs it into the jet-catching end 51 of the outlet exhaust fan assembly 44. This system is designed so that the rotting, or stagnant-air, areas are located between the jet-creating portions and the jet-catching portions of the fan assemblies so that a jet of air which is directed from outside the house wall 66 passes therethrough or near thereto. If it is necessary to locate a fan assembly 10, 44, 70 and/or 72 at a stagnant air area, it is also possible to place a cutout with a baffle 92 in the wall of the intermediate fan assembly for diverting a small amount of fresh jet-air to the rotting area. 
     The humidistats 90 are placed at the stagnant air, or rotting, areas so that when the humidity in one of these areas rises above a certain amount, a humidity switch 88 is closed, thereby activating fans in all the fan assemblies to create the jets for ventilating the stagnant air areas as described above. However, when it is raining and the humidity rises above the certain amount, although the humidity switches 88 will close, they will not operate the fans because the rain switch 84 will be open. This prevents the system from sucking rain into the crawl space. 
     It can be appreciated by those skilled in the art that the crawl-space jet-ventilation system described herein can be used for particularly targeting hard to ventilate stagnant areas of crawl spaces. The system can be easily mounted in existing crawl spaces with existing vent holes without changing the house in which they are mounted. 
     While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. For example, the jet-stream aiming member 42 could be used for aiming the initial jet-stream coming into a house crawl space in a particular direction. Other mechanisms could also be used as aiming devices. Further, the system could be used without the intermediate or outlet exhaust fan assemblies where it is not necessary to retain a jet-stream composed of air coming from outside the house for long distances and around turns. It is possible to construct the fan assemblies with structures other than those depicted herein.