Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
2000-11-06
2001-12-11
Walberg, Teresa (Department: 3742)
Pumps
Motor driven
Electric or magnetic motor
C417S046000, C222S383200
Reexamination Certificate
active
06328543
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to electrically powered fluid spray systems, and particularly to those spray systems needing non-pulsating sprays. Even more particularly, the present invention relates to fluid sprayers using gear pumps and replaceable fluid reservoirs.
BACKGROUND OF THE INVENTION
Sprayer pumps needing continuous fluid spraying are known to use miniature gear pumps to lift fluid from a reservoir and to develop the necessary pressure to enable a sprayer head to breakup the fluid sufficiently to generate a non-pulsating spray. Priming such pumps may take 10 seconds or more to replace air in a dip tube or delivery line with fluid. Expensive precision parts may be needed to lift a fluid more than a few inches. A check valve to prevent backflow to the reservoir may be needed to prevent losing the prime at the pump.
Fluids having surfactants therein are difficult to contain without leakage. Dribble at a sprayer head is especially undesirable. A check valve is often used immediately upstream of the sprayer head to minimize fluid volume available for dribble at the sprayer head outlet. The check valve typically has a cracking pressure or threshold pressure that has to be exceeded before fluid flow to the sprayer head may occur. The combination of suction needed for pump priming and fluid lifting, as well as the discharge cracking pressure, may be too much for an inexpensive gear pump to overcome.
What is needed is a simple gear pump and reservoir combination which minimizes the necessary suction for pump priming and fluid lifting so that a cracking pressure as high as 3.5 psig is exceeded by the pump. In addition, what is needed is a self-priming gear pump that is primed in one or two seconds. Furthermore, what is needed is a replaceable fluid reservoir that may be connected to a gear pump simply, yet in a leak-resistant manner.
SUMMARY OF THE INVENTION
In one preferred embodiment of the present invention, a gear pump and reservoir for a fluid sprayer comprise a motor driven gear pump having a mounting surface for attachment to a hand held appliance and a means for sealing the gear pump to a fluid reservoir. The fluid reservoir is located above the gear pump so that a static head of fluid in the reservoir maintains the gear pump in a primed state.
Also included is a fluid line leading from the gear pump to a sprayer head. The fluid line has a discharge check valve located therein, and the check valve has a cracking pressure higher than the static head of fluid so that fluid passes to the sprayer head only when the gear pump operates to increase pressure in the fluid line above the cracking pressure. The gear pump and reservoir further include means for powering and operating the motor driven gear pump such that the gear pump provides a continuous flow of fluid to the sprayer head upon demand by a user.
In another preferred embodiment of the present invention, a gear pump and reservoir for a fluid sprayer comprise a pump housing having a mounting surface for attachment to a hand held appliance and a recessed portion for receiving and sealing to a fluid reservoir. The pump housing also has a cavity for locating a drive motor and gears therein. The cavity has ribs therein forming pump passages including a pump inlet and a pump outlet. The recessed portion has a rigid conical projection centered therein which has an orifice extending into the pump inlet. The gear pump also includes an electric motor having a motor housing and a rotating shaft extending from the motor housing. The motor housing is connected to the pump housing via a resilient fluid sealing member. In addition, the gear pump includes a pinion gear mounted to the rotating shaft of the motor inside the cavity of the pump housing, and an idler gear rotatably connected within the cavity to engage the pinion gear. The gears, together with the pump passages in the cavity, substantially limit fluid backflow between mating gear teeth of the gears, and between gear teeth and pump walls, to form a gear pump. The pump outlet is in fluid communication with the gear pump and has a fluid line leading from the pump outlet to a sprayer head. The fluid line has a discharge check valve to minimize fluid dribbling at the sprayer head. The check valve has a cracking pressure. The gear pump further includes a fluid container mounted to the recessed portion of the pump housing to form a fluid reservoir. The container has an air vent valve to enable ambient air to replace fluid drawn from the reservoir and a fluid discharge valve. The fluid discharge valve is opened by engagement with the conical projection within the recessed portion to provide fluid communication to the pump inlet. The gear pump additionally includes means for powering and operating the motor such that the gear pump provides a continuous flow of fluid to the sprayer head upon demand by a user.
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Bamber Jeffrey V.
Fastovsky Leonid
Fayette Thibault
The Procter & Gamble & Company
Walberg Teresa
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