US3686693A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of conducting waste liquid by vacuum through long conduits of pneumatic sewage disposal systems
Assignee: Electrolux AB
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Filing: 1970-07-15
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Granted: 1972-08-29
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Expires: 1990-07-15
Abstract
Abstract A pneumatic sewage system has a long main conduit for conducting waste liquid to a receiving tank at a partial vacuum. Waste liquid from sanitary conveniences flows through branch conduits to the main conduit, intermittently a flow control valve in each branch conduit opening when waste liquid starts to flow and closing when flow of liquid stops. When all of the valves close at the same time a long column of liquid being propelled at a high velocity in the main conduit to the receiving tank will suddenly stop. When this occurs forces are developed which adversely affect the main conduit and equipment connected thereto. In accordance with my invention ambient air is mixed with waste liquid in each branch only during the intervals of time waste liquid is flowing therethrough and while it is open. The ambient air mixed with the waste liquid functions as a resilient damper that effectively absorbs the forces developed when the long column of liquid moving through the main conduit suddenly stops.
Inventors
- 👤 Sven Algot Joel Liljendahl
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 20:14
CPC Classifications
E; E03; E03F; E03F1/00; E03F1/006; E03F1/007; Y; Y10; Y10S; Y10S4/00; Y10S4/09; Y10T; Y10T137/00; Y10T137/2931; Y10T137/3109
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
83 words
In a method of conducting waste liquid in a pneumatic sewage disposal system through a relatively long primary pipe line or conduit to a receiving tank under vacuum from a plurality of sanitary conveniences communicating with said primary conduit, the improvement which comprises the steps of intermittently flowing waste liquid from a plurality of sanitary conveniences to said primary conduit, and mixing air with waste liquid only during the intervals of time such liquid flows from said sanitary conveniences to said primary conduit.
Claim 2
Dependent Claim
83 words
In a method of conducting waste liquid in a pneumatic sewage disposal system through a relatively long primary pipe line or conduit to a receiving tank under vacuum from a plurality of sanitary conveniences communicating with said primary conduit, the improvement which comprises the steps of intermittently flowing waste liquid from a plurality of sanitary conveniences to said primary conduit, and mixing air with waste liquid only during the intervals of time such liquid flows from said sanitary conveniences to said primary conduit.
Claim 3
Dependent Claim
79 words
The improvement set forth in claim 1 which comprises mixing a quantity of air with waste liquid from the sanitary conveniences which is dependent upon the volume of waste liquid flowing from the sanitary conveniences to said primary conduit and reducing the quantity of air mixed with waste liquid from the sanitary conveniences with an increase in the number of places of said primary conduit to which waste liquid is flowing at the same time from the sanitary conveniences.
Claim 4
Dependent Claim
144 words
In a pneumatic sewage disposal system having a relatively long primary path of flow for conducting waste liquid to a receiving place at a partial vacuum and a plurality of secondary paths of flow which are connected to said primary path of flow and can be closed and opened, each of said secondary paths of flow serving to conduct waste liquid intermittently from a sanitary convenience to a region of said primary path of flow, the improvement which comprises the steps of opening each secondary path of flow when waste liquid starts to flow therethrough from the sanitary convenience associated therewith and closing each secondary path of flow when such flow of waste liquid therethrough stops, and mixing air with waste liquid in each secondary path of flow only during the intervals of time waste liquid is flowing therethrough and while it is open.
Claim 5
Dependent Claim
144 words
In a pneumatic sewage disposal system having a relatively long primary path of flow for conducting waste liquid to a receiving place at a partial vacuum and a plurality of secondary paths of flow which are connected to said primary path of flow and can be closed and opened, each of said secondary paths of flow serving to conduct waste liquid intermittently from a sanitary convenience to a region of said primary path of flow, the improvement which comprises the steps of opening each secondary path of flow when waste liquid starts to flow therethrough from the sanitary convenience associated therewith and closing each secondary path of flow when such flow of waste liquid therethrough stops, and mixing air with waste liquid in each secondary path of flow only during the intervals of time waste liquid is flowing therethrough and while it is open.
Claim 6
Dependent Claim
62 words
The improvement set forth in claim 3 which comprises mixing air with waste liquid only while it is flowing in each secondary path of flow and while it is open at a rate which is dependent upon the partial vacuum in the system at the primary path of flow at which waste liquid flows thereto from each open secondary path of flow.
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) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |