Patent US4917142A successfully refreshed from Google Patents.
US4917142A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Secondary circulation unit
Assignee: Individual
•
Filing: 1989-09-29
•
Granted: 1990-04-17
•
Expires: 2009-09-29
Abstract
Abstract A device for effecting secondary circulation of water into a hot water tank not having a return opening. The arms of a T-fitting are place in series with the distribution line near the outlet port of the water tank. A return line, continuous at one end with the distal portion of the distribution line, is continuous at the other end with a relatively small internal line which lies within the leg of the T-fitting, one arm of the T-fitting, and extending through the outlet port into the water tank. A relatively low power pump and a sinking-ball valve are placed in series with the return line to cause the flow of water in the secondary circulation system to flow in one direction only.
Inventors
- 👤 Nikolaus L. Laing
- 👤 Ludwig Ludin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 10:08
CPC Classifications
F; F24; F24D; F24D17/00; F24D17/0078; F24H; F24H9/00; F24H9/12; F24H9/13; F24H9/133; Y; Y10; Y10T; Y10T137/00; Y10T137/6416; Y10T137/6497; Y10T137/8593; Y10T137/85954; Y10T137/85962; Y10T137/85978; Y10T137/86131
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
129 words
A water circulation system for a commercial or domestic building having a hot water distribution line and a hot water tank having a heat source, a cold water inlet port and a hot water outlet port in the water section of the tank, said system comprising: a T-connector having two arms and a leg; the two arms being placed in series with the distribution line near the outlet port; an internal line extending through the leg, past one arm of the T-connector, through the outlet port, and into the upper region of the water tank; a return line continuous at one end with the distal end of the distribution line, and at its other end with the internal line; and a pump placed in series with the return line.
Claim 2
Dependent Claim
129 words
A water circulation system for a commercial or domestic building having a hot water distribution line and a hot water tank having a heat source, a cold water inlet port and a hot water outlet port in the water section of the tank, said system comprising: a T-connector having two arms and a leg; the two arms being placed in series with the distribution line near the outlet port; an internal line extending through the leg, past one arm of the T-connector, through the outlet port, and into the upper region of the water tank; a return line continuous at one end with the distal end of the distribution line, and at its other end with the internal line; and a pump placed in series with the return line.
Claim 3
Dependent Claim
24 words
The system of claim 1 wherein the internal cross-section of the internal line is approximately 10% of the internal cross-section of the distribution line.
Claim 4
Dependent Claim
21 words
The system of claim 1 which further comprises a check valve in said return line between the pump and the T-connector.
Claim 5
Dependent Claim
14 words
The system of claim 3 wherein said check valve is integral with said T-connector.
Claim 6
Dependent Claim
12 words
The system of claim 4 wherein said check valve comprises a sinking-ball.
Claim 7
Dependent Claim
45 words
The system of claim 4 wherein said check valve further comprises: a non-concentric opening sized and dimensioned to seat the sinking-ball; a limiting wall dimensioned and positioned to maintain the sinking-ball within a close proximity of the non-concentric opening when said check valve is open.
References Cited (Backward Citations)
US1033588A
Cited
US1401523A
Cited
US2007872A
Cited
US2255460A
Cited
GB745262A
Cited
US2967666A
Cited
US2971532A
Cited
US2922469A
Cited
US4037567A
Cited
US4116379A
Cited
JPS5423236A
Cited
US4293093A
Cited
US4672990A
Cited
US4759382A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-16 | 1993-10-16 | 1994-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-16 | 1997-10-16 | 1998-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-16 | 2001-10-16 | 2002-04-17 | $7700.00 | Window Closed / Lapsed |