Baths – closets – sinks – and spittoons – Pool type – Accessory
Reexamination Certificate
2003-08-06
2004-11-16
Phillips, Charles E. (Department: 3751)
Baths, closets, sinks, and spittoons
Pool type
Accessory
Reexamination Certificate
active
06817042
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to pool drains for above ground swimming pool covers, and more particularly, to an automatic drain that is easy to install, and functions with minimal hardware to effectively remove collected rain water and accumulated debris without stretching, straining or otherwise damaging the pool cover.
2. Description of the Prior Art
Many approaches have been proposed by prior art workers for removing rainwater accumulated over covers to container vessels including swimming pools. Many of the swimming pool cover drains require electric motor driven pumps. Gasoline and other chemical storage vessels with closed tops drain the rainwater using gravity flow through the inside of a lattice of pipes to a common location from which the rainwater is drained.
U.S. Pat. No. 2,614,717 to Wiggins discloses a floating tank roof. This floating tank roof floats over the liquid in a tank and captures rainwater and snow without sinking. A central portion attached to rigid rings drains rainwater into the periphery of the roof surrounding the central rigid ring. A limber bottom as well as the weight of water collected in the central portion maintains the tapered bottom of the periphery. This taper allows the water to be gravity drained through a pipe connected to the periphery. Alternately, the central region may also have a drain connection. The floating tank roof disclosed by Wiggins does not drain all collected rainwater, and does not suggest features required for a pool cover drain.
U.S. Pat. No. 3,579,657 to Gurrieri discloses a swimming pool cover drain. The rainwater collected above the swimming pool cover is pumped through a filter with the same pump used to circulate the swimming pool water. A floating ball sensor determines when the swimming pool cover is pumped out. When the swimming pool cover is completely pumped a valve shuts the inlet allowing normal circulation of swimming pool water. The draining of collected rainwater requires the circulating pump to run. Separate valve hardware is required to prevent rainwater from entering the pool water.
U.S. Pat. No. 3,690,502 to Guber, Jr. discloses a pipe containing an annular pontoon floating roof, which has high enough buoyancy to float on a hydrocarbon liquid surface in a tank. The edges of the annular pontoon seal against the tank sidewalls prevent entry of rainwater into the hydrocarbon tank. A central box channel provides structural rigidity to the annular pontoon and also acts as a draining element for collected rainwater collected, which increases the density of the pontoon and may submerge it below the surface of the hydrocarbon liquid. The collected water is drained through a flexible hose, which passes through the hydrocarbon liquid into a drain outlet located on the sidewall of the tank. The central box channel is connected to a parallel array of chordal pipes to provide additional structural rigidity. The annular pontoon roof disclosed by the '502 patent does not suggest a drain for swimming pool covers. The sealed floating pontoon moves according to the amount of rainwater collected, thereby presenting an arrangement that does not apply to swimming pool covers.
U.S. Pat. No. 3,757,812 to Duncan discloses a roof standing water eliminator. It is installed in a low area in the roof A float sensor detects accumulation of water and activates a pump. When the accumulated water is exhausted, the same float sensor shuts off the pump. This drainage system proposed by the '812 patent is not suitable for draining swimming pool covers. It requires a pump driven by an electrical motor that is turned on when sufficient rainwater is collected.
U.S. Pat. No. 4,214,671 to McKibbin et al discloses a floating roof drainage system. A central drain connects a plurality of welded pipes on the roof to drain accumulated rainwater. Sleeve type couplings provide a hinge-like motion between welded segments, so that the floating roof can be moved. The edge of the floating roof is sealed against the tank to prevent rainwater from entering the product stored in the tank. U.S. Pat. No. 4,248,357 to Stafford discloses a floating roof drain. The floating roof edge is sealed against the tank wall by a seal strip. The floating roof collects rainwater and drains it through a central drain, which is connected to a coiled conduit connecting the central drain of the floating roof with a drain located in the bottom of the tank. When all the content of the tank is emptied, the floating roof essentially contacts the bottom of the tank and a frustoconical contour of the bottom, together with a cylindrical portion, accommodates the central drain and the coiled conduit. The '671 and '357 patents disclose floating roof rainwater draining systems having sealed edges. Such systems are not suitable for use as a swimming pool cover drain.
U.S. Pat. No. 4,318,421 to Ward discloses a float controlled siphon valve for a swimming pool cover. A hinged float is used to sense the water level and open a closure of a siphon inlet. The closure of the siphon is accomplished by a male opening and a female closure manufactured from a softer material, which moves away from the male member when the water level in the swimming pool cover rises. When the water level drops, the float moves downwards, forcing the female member over the male inlet creating a seal for the siphon system. The siphon system drains the accumulated rainwater over the pool cover by gravity without need of pumps, or the like. Drainage of water accumulated over the swimming pool cover is incomplete, since the float must remain primed at all times, and closes the valve before all the collected rainwater has been drained. Moreover, moving parts in the '421 patent system may become clogged with debris accumulated over the swimming pool cover.
U.S. Pat. No. 4,819,681 to Hodak discloses an apparatus and method for draining a swimming pool cover. A central drainage passage in a completely covered swimming pool cover is associated with upper and lower flanged members, which seal around a hole formed in the pool cover. The drain is connected to an elbow, which connects to a drain outlet located in a sidewall of the swimming pool. A flexible bellowed connection associated with the elbow accommodates the vertical motion of the water level or the swimming pool cover. A fixed rainwater liquid level is maintained above the pool cover to assure that the pool cover stays in place. This is accomplished by locating the drainage hole adjustably above the swimming pool cover. At all times, the level of rainwater is maintained above the swimming pool cover at a preset level by adjusting the position of the central drainage hole above the pool cover. A single central bole in the pool cover coupled with a large head of rainwater stresses the polymeric material of the swimming pool cover. This stress may enlarge the large central hole by tearing. Alternatively, the weight of rainwater above the swimming pool cover may tear the polymeric pool cover at the edges where it is attached. Excessive rainwater weight may also cause the swimming pool cover to become submerged beneath the water level in the pool.
U.S. Pat. No. 4,830,040 to Eng discloses an automatic swimming pool cover drainer. A float connected to a lever arm opens an inlet to a siphon valve and quickly closes when the water level reaches a preset value. Drainage of the water in the siphon exit line is thereby prevented so that the siphon action is not broken. The siphon discharge line is always filled with water. Electrical or mechanical means may be used to reset a latch mechanism assisting siphon valve closure. Water is always present on the swimming pool cover. Consequently, the plastic material of the swimming pool cover has to bear the weight of water, together with the sensing and activating mechanisms of the automatic drainer. Moreover the device disclosed by the patent does not empty out the accumulated rainwater completely. Accumulated debris on the swimming pool cover may int
Buff Ernest D.
Ernest D. Buff & Associates LLC
Narasimhau Dave
Phillips Charles E.
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