Patent US4380091A successfully refreshed from Google Patents.
US4380091A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Control circuitry for water level control of pools
Assignee: Individual
•
Filing: 1980-12-05
•
Granted: 1983-04-19
•
Expires: 2000-12-05
Abstract
Abstract Circuitry for automatically controlling the water level of swimming pools with a multi-level detecting sensor for directly sensing the pool water. A low voltage oscillator in the input portion of the circuitry detects the presence of water above or below each level sensing electrical contact of the sensor by a change in oscillator amplitude in response to impedance from the contact to ground. Signal threshold circuitry changes in output signal in response to the amplitude of the oscillator signal. Delay circuitry integrates the output of the threshold signal to avoid responding to spurious changes in water level, such as wave action in the pool. Monitor circuitry disposed between the delay circuitry and the water fill, water dump, and pump control circuitry monitors signals received from the sensor or generated by the input circuitry to detect any malfunctions in the sensor or the control circuitry, such as improper sequence of the water level signals, to disable further filling of the pool. Bi-stable switch circuitry controls filling of the pool and is responsive to differing pool levels to cause filling of the pool to commence or to stop.
Inventors
- 👤 Olin A. Lively
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 18:43
CPC Classifications
E; E04; E04H; E04H4/00; E04H4/12; Y; Y10; Y10T; Y10T137/00; Y10T137/7287; Y10T137/7303; Y10T137/7306
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
194 words
A system for controlling the level of water in a swimming pool, said system being adapted to control a fill valve to add water to the pool as required, and comprising, in combination: first water level sensing means positioned in said pool for producing a first output signal indicative of the presence or absence of water at a predetermined latch level within the pool; second water level sensing means positioned in said pool for producing a second output signal indicative of the presence or absence of water at a predetermined normal level within the pool above said latch level; control circuit means for opening said fill valve in response to said output signal from said first water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said output signal from said second water level sensing means indicating said water level rising to said normal level; and monitor circuit means responsive to said first and second output signals for disabling operation of said fill valve upon the occurrence of sensing water at said normal level without also sensing water at said latch level.
Claim 2
Independent Claim
194 words
A system for controlling the level of water in a swimming pool, said system being adapted to control a fill valve to add water to the pool as required, and comprising, in combination: first water level sensing means positioned in said pool for producing a first output signal indicative of the presence or absence of water at a predetermined latch level within the pool; second water level sensing means positioned in said pool for producing a second output signal indicative of the presence or absence of water at a predetermined normal level within the pool above said latch level; control circuit means for opening said fill valve in response to said output signal from said first water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said output signal from said second water level sensing means indicating said water level rising to said normal level; and monitor circuit means responsive to said first and second output signals for disabling operation of said fill valve upon the occurrence of sensing water at said normal level without also sensing water at said latch level.
Claim 3
Dependent Claim
57 words
A control system as defined in claim 1 wherein said system is further adapted to control the operation of a pump for circulating water within the pool, and wherein said monitor circuit means disable operation of said circulating pump upon the occurrence of sensing water at said normal level without also sensing water at said latch level.
Claim 4
Independent Claim
236 words
A system for controlling the level of water in a swimming pool, said system being adapted to control a fill valve to add water to the pool as required, and a dump valve for draining water from the pool as required, and comprising, in combination: first water level sensing means positioned in said pool for producing a first output signal indicative of the presence or absence of water at a predetermined latch level within the pool; second water level sensing means positioned in said pool for producing a second output signal indicative of the presence or absence of water at a predetermined normal level within the pool above said latch level; third water level sensing means positioned in said pool for producing a third output signal indicative of the presence or absence of water at a predetermined high level within the pool above said normal level; control circuit means for opening said fill valve in response to said output signal from said first water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said output signal from said second water level sensing means indicating said water level rising to said normal level; and additional control circuit means for opening said dump valve in response to said output signal from said third water level sensing means indicating said water level rising to said high level.
Claim 5
Independent Claim
236 words
A system for controlling the level of water in a swimming pool, said system being adapted to control a fill valve to add water to the pool as required, and a dump valve for draining water from the pool as required, and comprising, in combination: first water level sensing means positioned in said pool for producing a first output signal indicative of the presence or absence of water at a predetermined latch level within the pool; second water level sensing means positioned in said pool for producing a second output signal indicative of the presence or absence of water at a predetermined normal level within the pool above said latch level; third water level sensing means positioned in said pool for producing a third output signal indicative of the presence or absence of water at a predetermined high level within the pool above said normal level; control circuit means for opening said fill valve in response to said output signal from said first water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said output signal from said second water level sensing means indicating said water level rising to said normal level; and additional control circuit means for opening said dump valve in response to said output signal from said third water level sensing means indicating said water level rising to said high level.
Claim 6
Dependent Claim
39 words
A control system as defined in claim 3 wherein said additional control means open said dump valve only in response to said second and third output signals indicating the presence of water at said normal and high levels, respectively.
Claim 7
Dependent Claim
41 words
A control system as defined in claim 4 wherein said additional control means open said dump valve only in response to said first, second and third output signals indicating the presence of water at said latch, normal and high levels, respectively.
Claim 8
Dependent Claim
51 words
A control system as defined in claim 3 including monitor circuit means responsive to said first, second and third output signals for disabling operation of said fill valve upon the occurrence of sensing water at said high level without also sensing water at said latch level and at said normal level.
Claim 9
Dependent Claim
62 words
A control system as defined in claim 3 wherein said system is further adapted to control the operation of a pump for circulating water within the pool, and including monitor circuit means for disabling operation of said circulating pump upon the occurrence of sensing water at said high level without also sensing water at said latch level and at said normal level.
Claim 10
Independent Claim
224 words
A system for controlling the level of water in a swimming pool, said system being adapted to control a fill valve to add water to the pool as required, and comprising, in combination: first water level sensing means positioned in said pool for producing a first output signal indicative of the presence or absence of water at a predetermined latch level within the pool; second water level sensing means positioned in said pool for producing a second output signal indicative of the presence or absence of water at a predetermined normal level within the pool above said latch level; third water level sensing means positioned in said pool for producing a third output signal indicative of the presence or absence of water at a predetermined low level within the pool below said normal level; control circuit means for opening said fill valve in response to said output signal from said first water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said output signal from said second water level sensing means indicating said water level rising to said normal level; and additional control circuit means for disabling said fill valve in response to said output signal from said third water level sensing means indicating said water level falling below said low level.
Claim 11
Independent Claim
224 words
A system for controlling the level of water in a swimming pool, said system being adapted to control a fill valve to add water to the pool as required, and comprising, in combination: first water level sensing means positioned in said pool for producing a first output signal indicative of the presence or absence of water at a predetermined latch level within the pool; second water level sensing means positioned in said pool for producing a second output signal indicative of the presence or absence of water at a predetermined normal level within the pool above said latch level; third water level sensing means positioned in said pool for producing a third output signal indicative of the presence or absence of water at a predetermined low level within the pool below said normal level; control circuit means for opening said fill valve in response to said output signal from said first water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said output signal from said second water level sensing means indicating said water level rising to said normal level; and additional control circuit means for disabling said fill valve in response to said output signal from said third water level sensing means indicating said water level falling below said low level.
Claim 12
Dependent Claim
61 words
A control system as defined in claim 8 wherein said system is further adapted to control the operation of a pump for circulating water within the pool, and wherein said monitor circuit means disable operation of said circulating pump in response to said output signal from said third water level sensing means indicating said water level falling below said low level.
Claim 13
Independent Claim
280 words
A system for controlling the level of water in a swimming pool, said system being adapted to control a fill valve to add water to the pool as required, and a dump valve for draining water from the pool as required, and comprising, in combination: first water level sensing means positioned in said pool for producing a first output signal indicative of the presence or absence of water at a predetermined latch level within the pool; second water level sensing means positioned in said pool for producing a second output signal indicative of the presence or absence of water at a predetermined normal level within the pool above said latch level; third water level sensing means positioned in said pool for producing a third output signal indicative of the presence or absence of water at a predetermined high level within the pool above said normal level; fourth water level sensing means positioned in said pool for producing a fourth output signal indicative of the presence or absence of water at a predetermined low level within the pool below said latch level; control circuit means for opening said fill valve in response to said output signal from said first water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said output signal from said second water level sensing means indicating said water level rising to said normal level; and additional control circuit means for opening said dump valve in response to said output signals from said first, second, third and fourth water level sensing means indicating said water level rising above said latch, normal, high and low levels, respectively.
Claim 14
Independent Claim
280 words
A system for controlling the level of water in a swimming pool, said system being adapted to control a fill valve to add water to the pool as required, and a dump valve for draining water from the pool as required, and comprising, in combination: first water level sensing means positioned in said pool for producing a first output signal indicative of the presence or absence of water at a predetermined latch level within the pool; second water level sensing means positioned in said pool for producing a second output signal indicative of the presence or absence of water at a predetermined normal level within the pool above said latch level; third water level sensing means positioned in said pool for producing a third output signal indicative of the presence or absence of water at a predetermined high level within the pool above said normal level; fourth water level sensing means positioned in said pool for producing a fourth output signal indicative of the presence or absence of water at a predetermined low level within the pool below said latch level; control circuit means for opening said fill valve in response to said output signal from said first water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said output signal from said second water level sensing means indicating said water level rising to said normal level; and additional control circuit means for opening said dump valve in response to said output signals from said first, second, third and fourth water level sensing means indicating said water level rising above said latch, normal, high and low levels, respectively.
Claim 15
Dependent Claim
45 words
A control system as defined in claim 10 including alarm means for alerting an attendant, and wherein said additional control means include actuate said alarm means upon said water level rising above said latch, normal, high and low levels for a predetermined period of time.
Claim 16
Independent Claim
300 words
A system for controlling the level of water in a swimming pool, wherein the surface of the water is subject to repeated disturbances, said system being adapted to control a fill valve to add water to the pool as required, and comprising, in combination: first water level sensing means positioned in said pool and responsive to the disturbed surface thereof for producing a first output signal indicative of the instantaneous presence or absence of water at a predetermined normal water level within the pool; first delay circuit means associated with said first water level sensor means and responsive to said first output signal therefrom for producing a first delayed output signal only upon the duration of said first sensor output signal exceeding a first predetermined period of time; second water level sensing means positioned in said pool and responsive to the disturbed surface thereof for producing a second output signal indicative of the instantaneous presence or absence of water at a predetermined latch water level within the pool below said normal water level; second delay circuit means associated with said second water level sensor means and responsive to said second output signal therefrom for producing a second delayed output signal only upon the duration of said second sensor output signal exceeding a second predetermined period of time; said first and second predetermined periods of time being each greater than the average duration of the water surface disturbances; and control circuit means for opening said fill valve in response to said second delayed output signal from said second water level sensor means indicating said water level falling below said latch level, and for closing said fill valve in response to said first delayed output signal from said first water level sensor means indicating said water level rising to said normal level.
Claim 17
Independent Claim
300 words
A system for controlling the level of water in a swimming pool, wherein the surface of the water is subject to repeated disturbances, said system being adapted to control a fill valve to add water to the pool as required, and comprising, in combination: first water level sensing means positioned in said pool and responsive to the disturbed surface thereof for producing a first output signal indicative of the instantaneous presence or absence of water at a predetermined normal water level within the pool; first delay circuit means associated with said first water level sensor means and responsive to said first output signal therefrom for producing a first delayed output signal only upon the duration of said first sensor output signal exceeding a first predetermined period of time; second water level sensing means positioned in said pool and responsive to the disturbed surface thereof for producing a second output signal indicative of the instantaneous presence or absence of water at a predetermined latch water level within the pool below said normal water level; second delay circuit means associated with said second water level sensor means and responsive to said second output signal therefrom for producing a second delayed output signal only upon the duration of said second sensor output signal exceeding a second predetermined period of time; said first and second predetermined periods of time being each greater than the average duration of the water surface disturbances; and control circuit means for opening said fill valve in response to said second delayed output signal from said second water level sensor means indicating said water level falling below said latch level, and for closing said fill valve in response to said first delayed output signal from said first water level sensor means indicating said water level rising to said normal level.
Claim 18
Dependent Claim
33 words
A control system as defined in claim 12 wherein said first and second water level sensing means each include at least one exposed water sensing electrode mounted on the sidewall of the pool.
Claim 19
Dependent Claim
48 words
A control system as defined in claim 12 including system monitoring means for rendering said fill valve inoperative upon said delayed first output signal indicating the presence of water at said normal level and said delayed second output signal indicating the absence of water at said latch level.
Claim 20
Independent Claim
262 words
A system for controlling the level of water in a swimming pool, wherein the surface of the water is subject to repeated disturbances, said system being adapted to control a fill valve to add water to the pool, and a dump valve to empty water from the pool, and comprising, in combination: first, second and third water level sensing means positioned in said pool and responsive to the disturbed surface thereof for producing first, second and third output signals indicative of the instantaneous presence or absence of water within the pool at predetermined high, normal and low water levels, respectively; first, second and third delay circuit means associated with said first, second and third water level sensing means and responsive to said first, second and third output signals therefrom, respectively, for producing first, second and third delayed output signals only upon the duration of said output signals exceeding respective first, second and third predetermined periods of time each greater than the average duration of said water surface disturbances; and control circuit means for opening said fill valve in response to said delayed output signal from said third water level sensor means indicating said water level falling below said latch level, and for closing said fill valve in response to said delayed output signal from said second water level sensor means indicating said water level rising to said normal level, and for opening said dump valve in response to said delayed output signal from said first, second and third water level sensing means indicating said water level having risen to said high level.
Claim 21
Independent Claim
262 words
A system for controlling the level of water in a swimming pool, wherein the surface of the water is subject to repeated disturbances, said system being adapted to control a fill valve to add water to the pool, and a dump valve to empty water from the pool, and comprising, in combination: first, second and third water level sensing means positioned in said pool and responsive to the disturbed surface thereof for producing first, second and third output signals indicative of the instantaneous presence or absence of water within the pool at predetermined high, normal and low water levels, respectively; first, second and third delay circuit means associated with said first, second and third water level sensing means and responsive to said first, second and third output signals therefrom, respectively, for producing first, second and third delayed output signals only upon the duration of said output signals exceeding respective first, second and third predetermined periods of time each greater than the average duration of said water surface disturbances; and control circuit means for opening said fill valve in response to said delayed output signal from said third water level sensor means indicating said water level falling below said latch level, and for closing said fill valve in response to said delayed output signal from said second water level sensor means indicating said water level rising to said normal level, and for opening said dump valve in response to said delayed output signal from said first, second and third water level sensing means indicating said water level having risen to said high level.
Claim 22
Dependent Claim
34 words
A control system as defined in claim 15 wherein said first, second and third water level sensing means each include at least one exposed water sensing electrode mounted on the sidewall of the pool.
Claim 23
Independent Claim
253 words
A system for controlling the level of water in a swimming pool, wherein the surface of the water is subject to repeated disturbances, said system being adapted to control a water circulation pump, a fill valve to add water to the pool, and comprising, in combination: first, second and third water level sensing means positioned in said pool and responsive to the disturbed surface thereof for producing first, second and third output signals indicative of the instantaneous presence or absence of water within the pool at predetermined normal, latch and low water levels, respectively; first, second and third delay circuit means associated with said first, second and third water level sensing means and responsive to said first, second and third output signals therefrom, respectively, for producing first, second and third delayed output signals only upon the duration of said output signals exceeding respective first, second and third predetermined periods of time each greater than the average duration of said water surface disturbances; and control circuit means for opening said fill valve in response to said delayed output signal from said second water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said delayed output signal from said first water level sensing means indicating said water level rising to said normal level, and for interrupting operation of said pump in response to said delayed output signal from said third level sensing means indicating said water level having fallen below said low level.
Claim 24
Independent Claim
253 words
A system for controlling the level of water in a swimming pool, wherein the surface of the water is subject to repeated disturbances, said system being adapted to control a water circulation pump, a fill valve to add water to the pool, and comprising, in combination: first, second and third water level sensing means positioned in said pool and responsive to the disturbed surface thereof for producing first, second and third output signals indicative of the instantaneous presence or absence of water within the pool at predetermined normal, latch and low water levels, respectively; first, second and third delay circuit means associated with said first, second and third water level sensing means and responsive to said first, second and third output signals therefrom, respectively, for producing first, second and third delayed output signals only upon the duration of said output signals exceeding respective first, second and third predetermined periods of time each greater than the average duration of said water surface disturbances; and control circuit means for opening said fill valve in response to said delayed output signal from said second water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said delayed output signal from said first water level sensing means indicating said water level rising to said normal level, and for interrupting operation of said pump in response to said delayed output signal from said third level sensing means indicating said water level having fallen below said low level.
Claim 25
Dependent Claim
34 words
A control system as defined in claim 17 wherein said first, second and third water level sensing means each include at least one exposed water sensing electrode mounted on the sidewall of the pool.
Claim 26
Independent Claim
301 words
A system for controlling the level of water in a swimming pool, wherein the surface of the water is subject to repeated disturbances, said system being adapted to control a water circulation pump, a fill valve to add water to the pool, and a dump valve to empty water from the pool, and comprising, in combination: first, second, third and fourth water level sensing means positioned in said pool and responsive to the disturbed surface thereof for producing first, second, third and fourth output signals indicative of the instantaneous presence or absence of water within the pool at predetermined high, normal, latch and low water levels, respectively; first, second, third and fourth delay circuit means associated with said first, second, third and fourth water level sensing means and responsive to said first, second, third and fourth output signals therefrom, respectively, for producing first, second, third and fourth delayed output signals only upon the duration of said output signals exceeding respective first, second, third and fourth predetermined periods of time each greater than the average duration of said water surface disturbances; and control circuit means for opening said fill valve in response to said delayed output signal from said third water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said delayed output signal from said second water level sensing means indicating said water level rising to said normal level, and for opening said dump valve in response to said delayed output signal from said first water level sensing means indicating said water level having risen to said high level, and for interrupting operation of said pump in response to said delayed output signal from said fourth level sensing means indicating said water level having fallen below said low level.
Claim 27
Independent Claim
301 words
A system for controlling the level of water in a swimming pool, wherein the surface of the water is subject to repeated disturbances, said system being adapted to control a water circulation pump, a fill valve to add water to the pool, and a dump valve to empty water from the pool, and comprising, in combination: first, second, third and fourth water level sensing means positioned in said pool and responsive to the disturbed surface thereof for producing first, second, third and fourth output signals indicative of the instantaneous presence or absence of water within the pool at predetermined high, normal, latch and low water levels, respectively; first, second, third and fourth delay circuit means associated with said first, second, third and fourth water level sensing means and responsive to said first, second, third and fourth output signals therefrom, respectively, for producing first, second, third and fourth delayed output signals only upon the duration of said output signals exceeding respective first, second, third and fourth predetermined periods of time each greater than the average duration of said water surface disturbances; and control circuit means for opening said fill valve in response to said delayed output signal from said third water level sensing means indicating said water level falling below said latch level, and for closing said fill valve in response to said delayed output signal from said second water level sensing means indicating said water level rising to said normal level, and for opening said dump valve in response to said delayed output signal from said first water level sensing means indicating said water level having risen to said high level, and for interrupting operation of said pump in response to said delayed output signal from said fourth level sensing means indicating said water level having fallen below said low level.
Claim 28
Dependent Claim
35 words
A control system as defined in claim 19 wherein said first, second, third and fourth water level sensing means each include at least one exposed water sensing electrode mounted on the sidewall of the pool.
Claim 29
Dependent Claim
300 words
Control circuitry for controlling the level of water in a swimming pool, said control circuitry adapted for electrical connection to a water level sensor having four vertically spaced apart water level sensing positions, including in order of increasing elevation, a low position, a latch position, a normal position, and a high position, said sensor being adapted for placement in the swimming pool to directly sense the water level therein, said control circuitry being further adapted to control an electrically actuated water fill valve to add water to the pool and an electrically actuated water dump valve to empty water from the pool, said control circuitry comprising: input circuitry means for each of said four sensing positions, each of said input circuitry means being responsive to the level of water in the swimming pool at the respective sensing position to produce a change in output state responsive to the presence or absence of water in the pool at the respective sensing position; delay circuitry means in series with the output of each of said four input circuitry means to provide individual output signals delayed in time from a change in output state of the associated input circuitry means, at least some of said delay circuitry means being adapted to control the electrically actuated water fill or dump valves, whereby said control circuitry is responsive to the water level in the pool, but is not responsive to wave action in said pool; and monitor circuitry means for said latch, normal and high sensing positions to monitor the sequencing of said latch, normal and high levels, said monitor circuitry means being adapted to disable said water fill valve upon the occurrence of sensing water at the high sensing position without sensing water at either the normal sensing position or the latch sensing position.
Claim 30
Dependent Claim
300 words
Control circuitry for controlling the level of water in a swimming pool, said control circuitry adapted for electrical connection to a water level sensor having four vertically spaced apart water level sensing positions, including in order of increasing elevation, a low position, a latch position, a normal position, and a high position, said sensor being adapted for placement in the swimming pool to directly sense the water level therein, said control circuitry being further adapted to control an electrically actuated water fill valve to add water to the pool and an electrically actuated water dump valve to empty water from the pool, said control circuitry comprising: input circuitry means for each of said four sensing positions, each of said input circuitry means being responsive to the level of water in the swimming pool at the respective sensing position to produce a change in output state responsive to the presence or absence of water in the pool at the respective sensing position; delay circuitry means in series with the output of each of said four input circuitry means to provide individual output signals delayed in time from a change in output state of the associated input circuitry means, at least some of said delay circuitry means being adapted to control the electrically actuated water fill or dump valves, whereby said control circuitry is responsive to the water level in the pool, but is not responsive to wave action in said pool; and monitor circuitry means for said latch, normal and high sensing positions to monitor the sequencing of said latch, normal and high levels, said monitor circuitry means being adapted to disable said water fill valve upon the occurrence of sensing water at the high sensing position without sensing water at either the normal sensing position or the latch sensing position.
Claim 31
Dependent Claim
294 words
Control circuitry for controlling the level of water in a swimming pool, said control circuitry adapted for electrical connection to a water level sensor having four vertically spaced apart water level sensing positions, including in order of increasing elevation, a low position, a latch position, a normal position, and a high position, said sensor being adapted for placement in the swimming pool to directly sense the water level therein, said control circuitry being further adapted to control an electrically actuated water fill valve to add water to the pool and an electrically actuated water dump valve to empty water from the pool, said control circuitry comprising: input circuitry means for each of said four sensing positions, each of said input circuitry means being responsive to the level of water in the swimming pool at the respective sensing position to produce a change in output state responsive to the presence or absence of water in the pool at the respective sensing position: delay circuitry means in series with the output of each of said four input circuitry means to provide individual output signals delayed in time from a change in output state of the associated input circuitry means, at least some of said delay circuitry means being adapted to control the electrically actuated water fill or dump valves, whereby said control circuitry is responsive to the water level in the pool, but is not responsive to wave action in said pool; and monitor circuitry means for said latch, normal and high sensing positions to monitor the sequencing of said latch, normal and high levels, said monitor circuitry means being adapted to disable said water fill valve upon the occurrence of sensing water at the normal sensing position without sensing water at the latch sensing position.
Claim 32
Dependent Claim
294 words
Control circuitry for controlling the level of water in a swimming pool, said control circuitry adapted for electrical connection to a water level sensor having four vertically spaced apart water level sensing positions, including in order of increasing elevation, a low position, a latch position, a normal position, and a high position, said sensor being adapted for placement in the swimming pool to directly sense the water level therein, said control circuitry being further adapted to control an electrically actuated water fill valve to add water to the pool and an electrically actuated water dump valve to empty water from the pool, said control circuitry comprising: input circuitry means for each of said four sensing positions, each of said input circuitry means being responsive to the level of water in the swimming pool at the respective sensing position to produce a change in output state responsive to the presence or absence of water in the pool at the respective sensing position: delay circuitry means in series with the output of each of said four input circuitry means to provide individual output signals delayed in time from a change in output state of the associated input circuitry means, at least some of said delay circuitry means being adapted to control the electrically actuated water fill or dump valves, whereby said control circuitry is responsive to the water level in the pool, but is not responsive to wave action in said pool; and monitor circuitry means for said latch, normal and high sensing positions to monitor the sequencing of said latch, normal and high levels, said monitor circuitry means being adapted to disable said water fill valve upon the occurrence of sensing water at the normal sensing position without sensing water at the latch sensing position.
References Cited (Backward Citations)
US2793653A
Cited
US2885118A
Cited
US3020924A
Cited
US3291149A
Cited
US3386107A
Cited
US3537111A
Cited
US3605798A
Cited
US3668713A
Cited
US3732556A
Cited
US3757317A
Cited
US3882967A
Cited
US3759286A
Cited
US3848627A
Cited
US3739405A
Cited
US3837015A
Cited
US3916961A
Cited
US3939360A
Cited
US3953843A
Cited
US3942247A
Cited
US4061442A
Cited
US4133059A
Cited
US4135548A
Cited
US4165509A
Cited
US4265598A
Cited
US4211249A
Cited
US4342125A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-04-18 | 1986-10-18 | 1987-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-04-18 | 1990-10-18 | 1991-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-04-18 | 1994-10-18 | 1995-04-19 | $7700.00 | Window Closed / Lapsed |