US3787829A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Depleted liquid supply indicator
Assignee: MDT Corp
•
Filing: 1972-07-03
•
Granted: 1974-01-22
•
Expires: 1992-07-03
Abstract
Abstract Means for indicating when a liquid supply, such as a drum or like container, is depleted. The means includes a chamber which houses a level indicator, the chamber having an inlet and an outlet. The chamber is arranged so that its inlet communicates adjacent the bottom of the drum. Liquid is then pumped from the drum through this chamber, so as to maintain the chamber filled while the drum is being emptied. When the liquid supply in the drum is sufficiently depleted, continued pumping results in at least partial emptying of the chamber, which in turn activates the level sensor to indicate that the supply has been depleted.
Inventors
- 👤 M Schneier
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:23
CPC Classifications
G; G01; G01F; G01F23/00; G01F23/30; G01F23/64; G01F23/0007
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
225 words
A depleted liquid supply indicator comprising: a. an elongated upright tubular member having its lower end open, said member adapted to extend down into a liquid supply container so as to locate said lower end adjacent the bottom of said container; b. valve means in the upper end of said member permitting escape of air from said member as said member is inserted down into said liquid supply and liquid rises in said member, said valve means preventing entry of air into saId member as said liquid supply is depleted, so that a column of liquid is maintained in said tubular member; c. a level sensor in the lower portion of said tubular member for providing an indication of the existence of a low liquid level in said tubular member; d. a pump inlet pipe within said tubular member, said pipe having its intake located within said member adjacent said liquid level sensor and said pipe running up said tubular member through the top thereof for connection to a pump, the passage of said pipe through the top of said member being air tight; and e. said liquid column being slowly depleted when the level of said liquid supply falls below said open lower end and air enters said member, whereby said sensor gives a low level signal when said liquid column is substantially depleted.
Claim 2
Dependent Claim
225 words
A depleted liquid supply indicator comprising: a. an elongated upright tubular member having its lower end open, said member adapted to extend down into a liquid supply container so as to locate said lower end adjacent the bottom of said container; b. valve means in the upper end of said member permitting escape of air from said member as said member is inserted down into said liquid supply and liquid rises in said member, said valve means preventing entry of air into saId member as said liquid supply is depleted, so that a column of liquid is maintained in said tubular member; c. a level sensor in the lower portion of said tubular member for providing an indication of the existence of a low liquid level in said tubular member; d. a pump inlet pipe within said tubular member, said pipe having its intake located within said member adjacent said liquid level sensor and said pipe running up said tubular member through the top thereof for connection to a pump, the passage of said pipe through the top of said member being air tight; and e. said liquid column being slowly depleted when the level of said liquid supply falls below said open lower end and air enters said member, whereby said sensor gives a low level signal when said liquid column is substantially depleted.
Claim 3
Dependent Claim
28 words
A depleted liquid supply indicator as set forth in claim 1, in which said pipe intake is located in said tubular member below the level of said sensor.
Claim 4
Dependent Claim
43 words
A depleted liquid supply indicator as set forth in claim 1, in which the wall of said tubular member is provided with at least one liquid passage adjacent its lower end to facilitate passage of liquid into and out of said tubular member.
Claim 5
Dependent Claim
191 words
A depleted liquid supply indicator comprising: a. a housing defining a chamber; b. an intake tube communicating with said chamber through the bottom of said housing and adapted to extend into said liquid supply to a point adjacent the bottom thereof; c. an outlet tube communicating with said chamber through the bottom of said housing, said outlet tube extending downwardly and then upwardly above said housing to form a generally U-shaped, one end of said outlet tube being adapted to connect to a pump for pumping liquid from said liquid supply through said chamber; d. a priming tube having one end communicating with said chamber through the top of said housing and a second end communicating with said outlet tube at a point above said housing; e. valve means in said priming tube which is opened to connect the top and bottom of said chamber with said pump for priming said chamber and closed to establish flow through said chamber from said intake tube to said outlet tube; and f. a level sensor in said chamber for providing an indication of the existance of a low liquid level in said chamber.
Claim 6
Dependent Claim
191 words
A depleted liquid supply indicator comprising: a. a housing defining a chamber; b. an intake tube communicating with said chamber through the bottom of said housing and adapted to extend into said liquid supply to a point adjacent the bottom thereof; c. an outlet tube communicating with said chamber through the bottom of said housing, said outlet tube extending downwardly and then upwardly above said housing to form a generally U-shaped, one end of said outlet tube being adapted to connect to a pump for pumping liquid from said liquid supply through said chamber; d. a priming tube having one end communicating with said chamber through the top of said housing and a second end communicating with said outlet tube at a point above said housing; e. valve means in said priming tube which is opened to connect the top and bottom of said chamber with said pump for priming said chamber and closed to establish flow through said chamber from said intake tube to said outlet tube; and f. a level sensor in said chamber for providing an indication of the existance of a low liquid level in said chamber.
Claim 7
Dependent Claim
176 words
A depleted liquid supply indicator comprising: a. a housing enclosing a chamber: b. a liquid intake tube communicating with said chamber through the bottom of said housing, said intake tube being adapted to extend from said housing and down into a liquid supply container so as to locate the lower end of said intake tube adjacent the bottom of the liquid supply container; c. a generally U-shaped outlet tube having one leg communicating with said chamber through the bottom of said housing and a second leg adapted for connection to a pump, a portion of said second leg rising above the level of said housing; d. means communicating with said chamber through the top of said housing for priming said chamber so that said chamber remains filled with liquid until the liquid level in the supply container falls below the lower end of said intake tube; and e. a level sensor in said chamber; and f. indicating means acting responsive to said level sensor for indicating the existence of a low liquid level in said chamber.
Claim 8
Dependent Claim
176 words
A depleted liquid supply indicator comprising: a. a housing enclosing a chamber: b. a liquid intake tube communicating with said chamber through the bottom of said housing, said intake tube being adapted to extend from said housing and down into a liquid supply container so as to locate the lower end of said intake tube adjacent the bottom of the liquid supply container; c. a generally U-shaped outlet tube having one leg communicating with said chamber through the bottom of said housing and a second leg adapted for connection to a pump, a portion of said second leg rising above the level of said housing; d. means communicating with said chamber through the top of said housing for priming said chamber so that said chamber remains filled with liquid until the liquid level in the supply container falls below the lower end of said intake tube; and e. a level sensor in said chamber; and f. indicating means acting responsive to said level sensor for indicating the existence of a low liquid level in said chamber.
Claim 9
Dependent Claim
81 words
A depleted liquid supply indicator as set forth in claim 5, wherein said means comprises a priming tube having one end communicating with said chamber through the top of said housing and a second end communicating with said outlet tube at a point above said housing top; and valve means in said priming tube, said valve being open for completely filling said chamber with liquid and said valve thereafter being closed to maintain said prime until said liquid supply is depleted.
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) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |