US3876338A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid level control
Assignee: Whirlpool Corp
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Filing: 1973-03-15
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Granted: 1975-04-08
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Expires: 1993-03-15
Abstract
Abstract A control for preventing overflow of fill liquid in a liquid receiver such as a dishwasher tub. The control automatically effects an operation of drain means associated with the tub whenever the level rises above a preselected full level. The control utilizes a unidirectional pump system for both a recirculation and drain function by selectively air locking the drain pump during the recirculation operation to prevent draining of the tub at that time.
Inventors
- 👤 Jr Wilbur W Jarvis
- 👤 Leslie Toth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:03
CPC Classifications
A; A47; A47L; A47L15/00; A47L15/42; A47L15/4244
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
112 words
In a dishwasher, a liquid flow control comprising: a receptacle adapted to hold liquid; a pump; means for providing liquid to said receptacle; means connecting said pump to said receptacle in liquid transfer association therewith; and means for selectively operating said pump to pump said liquid from said receptacle including means sensing the liquid level in the receptacle and responsive thereto for selectively delivering gaseous fluid to the pump to cause an air lock thereof when the level of liquid in said receptacle is below a preselected level, and for preventing the delivery of said gaseous fluid to the pump to prevent said air lock when the level reaches said preselected level.
Claim 2
Dependent Claim
112 words
In a dishwasher, a liquid flow control comprising: a receptacle adapted to hold liquid; a pump; means for providing liquid to said receptacle; means connecting said pump to said receptacle in liquid transfer association therewith; and means for selectively operating said pump to pump said liquid from said receptacle including means sensing the liquid level in the receptacle and responsive thereto for selectively delivering gaseous fluid to the pump to cause an air lock thereof when the level of liquid in said receptacle is below a preselected level, and for preventing the delivery of said gaseous fluid to the pump to prevent said air lock when the level reaches said preselected level.
Claim 3
Dependent Claim
13 words
The dishwasher of claim 1 wherein said pump comprises a unidirectional, rotary pump.
Claim 4
Dependent Claim
24 words
The dishwasher of claim 1 wherein said air lock providing means includes a timer for effecting air lock of the pump at preselected times.
Claim 5
Dependent Claim
17 words
The dishwasher of claim 1 wherein said air lock providing means includes a bimetallic-transducer operated air valve.
Claim 6
Dependent Claim
17 words
The dishwasher of claim 1 wherein said air lock providing means includes an electrically driven air valve.
Claim 7
Dependent Claim
123 words
In a dishwasher having a tub for holding a quantity of washing liquid, and means for delivering washing liquid to the tub, a liquid level control means comprising: a unidirectionally driven pump having first pumping means for forcibly circulating the liquid for washing objects in the tub, and a second pumping means for pumping liquid from the tub for draining the tub; and air lock means including means sensing the liquid level in the tub and responsive thereto for selectively delivering gaseous fluid to said second pumping means to cause an air lock of said second pumping means for selectively preventing draining of the liquid from the tub when the level of washing liquid in the tub is below a preselected overfill level.
Claim 8
Dependent Claim
123 words
In a dishwasher having a tub for holding a quantity of washing liquid, and means for delivering washing liquid to the tub, a liquid level control means comprising: a unidirectionally driven pump having first pumping means for forcibly circulating the liquid for washing objects in the tub, and a second pumping means for pumping liquid from the tub for draining the tub; and air lock means including means sensing the liquid level in the tub and responsive thereto for selectively delivering gaseous fluid to said second pumping means to cause an air lock of said second pumping means for selectively preventing draining of the liquid from the tub when the level of washing liquid in the tub is below a preselected overfill level.
Claim 9
Dependent Claim
47 words
The dishwasher of claim 6 wherein said air lock means includes a timer and means operated by the timer for controlling the initiation and duration of operation of the pumping means for draining the tub at a preselected time during the operating cycle of the washing apparatus.
Claim 10
Dependent Claim
30 words
The dishwasher of claim 6 wherein said air lock means includes an air duct having an inlet disposed superjacent said overfill level, and an outlet to said second pumping means.
Claim 11
Dependent Claim
44 words
The dishwasher of claim 6 wherein said air lock means includes an air duct having an inlet disposed superjacent said overfill level, an outlet to said second pumping means, and an air valve for controlling passage of air from said inlet to said outlet.
Claim 12
Dependent Claim
51 words
The dishwasher of claim 6 wherein said air lock means includes an air duct having an inlet disposed superjacent said overfill level, an outlet to said second pumping means, an air valve for controlling passage of air from said inlet to said outlet, and means for cyclically closing said air valve.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-04-07 | 1978-10-07 | 1979-04-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-04-07 | 1982-10-07 | 1983-04-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-04-07 | 1986-10-07 | 1987-04-08 | $7700.00 | Window Closed / Lapsed |