Ventilation – Having inlet airway – Including specific air distributor
Reexamination Certificate
1999-08-17
2001-09-18
Joyce, Harold (Department: 3749)
Ventilation
Having inlet airway
Including specific air distributor
C454S290000, C454S308000
Reexamination Certificate
active
06290596
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to an air diffuser designed for underfloor air distribution systems, and to a mold and method for making the diffuser. The diffuser is mounted, with a specially designed mounting system, in the floor that separates the plenum of the air distribution system from the room or other enclosure to be heated, cooled or ventilated.
BACKGROUND
Underfloor air distribution has gained popularity in work environments due to its design flexibility and reconfiguration capabilities. While early underfloor air distribution systems were designed for spaces housing large computer systems, the increased use of local area networks and telecommunication systems are requiring entire buildings to be designed with underfloor air distribution systems that provide large quantities of cooling air. Also, with the trend to more frequent office reorganization, flexible offices with electrical and mechanical systems that can be easily reconfigured at minimum cost to accommodate personnel and hardware requirements are in increased demand.
Bottom source or underfloor air distribution systems typically include a number of small diffusers that can be moved to accommodate frequent changes in space usage and the resulting changes in ventilation requirements. The diffusers are typically mounted in a raised floor that defines the top surface of a plenum chamber. In other words, the space beneath the floor panels constitutes an enclosed plenum chamber or air space in which the air pressure is greater than in the room or other enclosure to be heated, cooled or ventilated. Air flows from the plenum chamber through the diffusers into the room or other enclosure. For optimal performance, diffusers should expel air in a swirling air pattern with little or no turbulence and, to prevent drafts, relatively low jet velocities. This pattern promotes high induction or entrainment rates that mix unconditioned air within the room with the air being supplied through the diffusers, thereby providing comfortable air movement and eliminating or reducing air stagnation and stuffiness.
One known underfloor air distribution system, produced by Krantz, is an injection molded device consisting of a diffuser grille, a damper, a basket, a trim frame and a retaining frame. The damper is placed within the basket, and the diffuser is placed on top of the basket. The basket is inserted into the trim frame, which is inserted into the retaining frame. The retaining frame, in turn, can be affixed to flooring panels for access to the underfloor air plenum supply. The grille is designed with a circular configuration and has air slots which extend radially from the center of the grille to the outside edge of the grille. The slots can vary in length and width, but have a uniform slope.
Typical underfloor air distribution systems, such as those produced by Krantz, are difficult to manufacture due to the intricate nature of the grilles. Currently, grilles manufactured from a composite material are produced in injection-type molds with retractable core pins that form the intricate pattern of slots in the grille. After molding, each core pin must be retracted from the grille so that the grille can be removed from the mold. This adds a significant increment of time, perhaps 50 to 100%, to the time that would be required to produce the grille if it could be produced on a solid mold with fixed core pins. The retractable core pins also multiply the costs to produce and maintain the equipment. The costs for molds for previous diffuser grilles, with retractable core pins, has been estimated to be at least $500,000, whereas a solid mold for producing the same grille, if this could be done, might cost less than $100,000. The retractable core pins also increase the maintenance costs substantially. With all off these costs and disadvantages, molds with retractable core pins would normally be considered cost prohibitive for this type of diffuser. Thus, to reduce equipment cost, manufacturing time and the costs of the molded grilles, there is a need for grille designs, and production equipment and methods, whereby the grille is readily and easily removed from a solid mold with fixed core pins.
SUMMARY OF THE INVENTION
The present invention provides a diffuser for underfloor air distribution with a grille having generally helical slots with substantially straight sides along arcuate sections through said slots. These slots produce a swirling air flow pattern with high induction. Unlike previous diffusers for this type of flow pattern, however, the helical air slots of this invention allow the grille to be rotated or spun off a solid mold core. The ability to quickly remove the grille from the mold core is a dramatic improvement over current manufacturing techniques in which each individual mold insertion must be separately retracted from the respective air slot in order to remove the grille. Since the grille of this invention can be produced with a solid mold, the costs of the mold and molding time are both significantly lower than with prior art molds with retractable core pins.
In the preferred embodiment, the diffuser grille sets on a dust receptacle or basket-shaped housing that is supported by a mounting assembly in the floor. A flow regulator or damper nests inside the housing. Both the housing and the flow regulator have vertically extending air slots extending through their side walls. Air from the underfloor air plenum passes through these slots into the diffuser and is forced through the helical slots in the grille into the room above the diffuser. The air flow rate can be adjusted by rotating the flow regulator within the housing so that the slots in the flow regulator are either in or out of registry with the slots in the housing.
The preferred grille for this diffuser rests on top of the rim of the housing, and the flow regulator has a series of pins that project into grille slots. The rim of the housing and the outer surface of the grille have mating rings of shallow, generally V-shaped teeth. The slopes of the sides of these teeth are designed to allow the grille to be rotated, thereby adjusting the air flow rate, with gentle manual pressure. The grilles will not rotate, however, if a heavier weight such as a person or a piece of furniture is on the diffuser.
The invention also provides a mounting system for securing the diffusers in floors above underfloor air distribution systems. The mounting system includes a trim ring that extends through a hole in the floor and a retaining ring. The trim ring has a rim that rests on the floor. The retainer ring is shaped so that it can be dropped through the hole in the floor and then pulled up onto the trim ring, with the floor gripped between the retaining ring and the rim of the trim ring. The preferred retainer ring is movably fixed to the trim ring by a ratchet-like latching mechanism that allows the retainer ring to be rotated about and onto the trim ring. This accommodates various thicknesses of flooring panels. Once the trim ring is properly positioned, the retainer ring is ratcheted onto the trim ring to securely attach the diffuser to the floor.
The diffuser can be rapidly converted to an electrical power/data port by removing the grille, flow regulator and housing, and replacing them with a power/data port cover with one or more openings for electrical cables. The power/data port cover is supported by the trim ring that also supports the housing, flow regulator and grille of the air diffuser. This further improves the flexibility of the system by allowing a fixture that had been an air diffuser to be quickly converted into an electrical power/data port, or vice versa. Other features and advantages of this invention will be apparent from the following description.
REFERENCES:
patent: 2381345 (1945-08-01), Greenlaw
patent: 2505394 (1950-04-01), Goettl
patent: 3837612 (1974-09-01), Deters
patent: 4145961 (1979-03-01), Lolli
patent: 4259898 (1981-04-01), Finkelstein et al.
patent: 4291615 (1981-09-01), Sodec
patent: 4303007 (1981-12-01), Riegel et al.
patent:
Birdsong John R.
Porter Kennon B.
Calfee Halter & Griswold LLP
Joyce Harold
Tomkins Industries Inc.
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