US3581895A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic backwashing filter system for swimming pools
Assignee: Marine Swimming Pool Equipment Co
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Filing: 1969-02-28
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Granted: 1971-06-01
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Expires: 1989-02-28
Abstract
Abstract A pressure-responsive switch senses the rising back pressure in a sand filter caused by debris collected in the filter, and at a predetermined pressure indicating the need for cleaning the filter, it triggers the reversal of valve means which reverses the flow in the filter and backwashes the debris into a separating tank where the debris is collected from the backwash flow which is then returned to the swimming pool. A timer controls the backwashing interval, at the end of which the valve is again reversed by a reversing mechanism, returning the system to normal filtering operation.
Inventors
- 👤 Herbert H Howard
- 👤 Henry R Young
- 👤 Jack A Berg
- 👤 Bernard Bellinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 15:10
CPC Classifications
B; B01; B01D; B01D24/00; B01D24/02; B01D24/10; B01D24/14; B01D24/38; B01D24/44; B01D24/46; B01D24/4631; B01D24/4642; B01D24/48; B01D24/4884; B01D29/00; B01D29/11; B01D29/13; B01D29/23; B01D29/27
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
313 words
In a swimming pool filtering system, in combination: a filter comprising a housing and a filtering bed therein, said housing having an inlet and an outlet for normal filtering flow therethrough; a separating tank for receiving and collecting foreign material backwashed out of said filter by reverse flow therethrough, said tank having an inlet and an outlet; a circulating system including a unidirectional flow pump for normally circulating a filtering flow of water from said pool to said filter inlet and from said filter outlet to a return to said pool; a reversing valve having connections to said pump, said filter, said return and said separating tank such that in a normal filtering position of said valve it will direct said filtering flOw through said filter, and in a reversed position of said valve it will direct a backwash flow through said filter and through said separating tank for backwashing foreign material from said filter and collecting it in said tank; valve operating means for shifting said valve from its normal filtering position to its reversed position and back to its normal filtering position; and control means including: 1. a device sensing the pressure in said filter and initiating the shifting of said valve to said reversed position when said pressure rises to a predetermined upper limit due to accumulation of foreign material in said filter; 2. a timer operable to start a timing operation in response to said valve-shifting to reversed position and, at the end of said timing operation to initiate return shifting of said valve from its backwash position to its normal position; and 3. limiting means for arresting operations of said valveoperating means at the ends of respective half-cycles of its operation so as to leave the valve in its respective backwash and normal filtering positions; said pump operating continuously during operation of said control means and independently thereof.
Claim 2
Dependent Claim
313 words
In a swimming pool filtering system, in combination: a filter comprising a housing and a filtering bed therein, said housing having an inlet and an outlet for normal filtering flow therethrough; a separating tank for receiving and collecting foreign material backwashed out of said filter by reverse flow therethrough, said tank having an inlet and an outlet; a circulating system including a unidirectional flow pump for normally circulating a filtering flow of water from said pool to said filter inlet and from said filter outlet to a return to said pool; a reversing valve having connections to said pump, said filter, said return and said separating tank such that in a normal filtering position of said valve it will direct said filtering flOw through said filter, and in a reversed position of said valve it will direct a backwash flow through said filter and through said separating tank for backwashing foreign material from said filter and collecting it in said tank; valve operating means for shifting said valve from its normal filtering position to its reversed position and back to its normal filtering position; and control means including: 1. a device sensing the pressure in said filter and initiating the shifting of said valve to said reversed position when said pressure rises to a predetermined upper limit due to accumulation of foreign material in said filter; 2. a timer operable to start a timing operation in response to said valve-shifting to reversed position and, at the end of said timing operation to initiate return shifting of said valve from its backwash position to its normal position; and 3. limiting means for arresting operations of said valveoperating means at the ends of respective half-cycles of its operation so as to leave the valve in its respective backwash and normal filtering positions; said pump operating continuously during operation of said control means and independently thereof.
Claim 3
Dependent Claim
40 words
a timer operable to start a timing operation in response to said valve-shifting to reversed position and, at the end of said timing operation to initiate return shifting of said valve from its backwash position to its normal position; and
Claim 4
Dependent Claim
40 words
a timer operable to start a timing operation in response to said valve-shifting to reversed position and, at the end of said timing operation to initiate return shifting of said valve from its backwash position to its normal position; and
Claim 5
Dependent Claim
45 words
A filtering system as defined in claim 1, said valve-operating means including an electric servomotor; and said limiting means including respective limit switches mechanically operated by said valve-operating means to deenergize said motor when said valve arrives at its backwash and normal filtering positions respectively.
Claim 6
Dependent Claim
208 words
A filtering system as defined in claim 1, wherein said valve comprises: a cylindrical casing having an intermediate inlet receiving the discharge of said pump, a first outlet at one end of said casing directing the flow to said separating tank inlet, a first port, between said inlet and said first outlet, connected to said filter inlet, a second outlet at the other end of said casing, for directing flow to said pool return, a second port, between said inlet and said second outlet, connected to said filter outlet; and a piston valve, including axially spaced first and second pistons, slidable axially in said casing between normal positions wherein said first piston blocks flow between said first port and said first outlet while directing flow from said inlet to said first port and said second piston directs flow from said second port to said second outlet while blocking flow between said inlet and said second port, and backwash positions wherein said first piston directs backwash flow from said first port to said first outlet while blocking flow between said inlet and said first port, and said second piston blocks flow between said second port and said second outlet while directing flow from said inlet to said second port.
Claim 7
Dependent Claim
45 words
limiting means for arresting operations of said valve-operating means at the ends of respective half-cycles of its operation so as to leave the valve in its respective backwash and normal filtering positions; said pump operating continuously during operation of said control means and independently thereof.
Claim 8
Dependent Claim
45 words
limiting means for arresting operations of said valve-operating means at the ends of respective half-cycles of its operation so as to leave the valve in its respective backwash and normal filtering positions; said pump operating continuously during operation of said control means and independently thereof.
Claim 9
Dependent Claim
20 words
A filtering system as defined in claim 1, wherein said separating tank outlet is connected directly to said pool return.
Claim 10
Dependent Claim
22 words
A filtering system as defined in claim 1, wherein said separating tank outlet is directly connected to the inlet of said pump.
Claim 11
Dependent Claim
31 words
A filtering system as defined in claim 1, wherein said separating tank has its inlet connected to said valve so as to receive its sole inlet flow directly from said valve.
Claim 12
Dependent Claim
49 words
A filtering system as defined in claim 1, wherein said separating tank has its inlet connected to said valve so as to receive its sole inlet flow directly from said valve; and its outlet connected directly to said pool return so as to deliver its discharge into the pool.
Claim 13
Dependent Claim
72 words
A filtering system as defined in claim 1, including: a timer switch operable under the control of said pressure sensing means to start the timing operation of said timer during said valve-shifting to reversed position; and a return-starting switch actuated by said timer at the end of said timing operation, to initiate the operation of said valve-operating means for shifting said valve from said reversed position back to said normal filtering position.
Claim 14
Dependent Claim
97 words
A filtering system as dEfined in claim 1: said sensing device including a pressure-sensitive starting switch; said valve operating means including an electric motor started in response to closing of said starting switch; a holding switch actuated by initial operation of said motor to continue the operation of said motor to the point where said valve is reversed, whereby said starting switch may open in response to pressure drop without arresting the operation of said motor; and a timer switch operable in response to said actuation of said holding switch, to start the operation of said timer.
Claim 15
Dependent Claim
45 words
A filtering system as defined in claim 9: and a return-starting switch actuated by said timer at the end of said timing operation, to initiate the operation of said valve-operating means for shifting said valve from said reversed position back to said normal filtering position.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-31 | 1974-11-30 | 1975-06-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-31 | 1978-11-30 | 1979-06-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-31 | 1982-11-30 | 1983-06-01 | $7700.00 | Window Closed / Lapsed |