US3686451A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid level control assembly
Assignee: Individual
•
Filing: 1971-02-01
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Granted: 1972-08-22
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Expires: 1991-02-01
Abstract
Abstract The liquid level control assembly disclosed includes a housing adapted for mounting in the wall of a vessel containing corrosive liquid or vapor. The housing has a control section and an opening connecting the inside of the vessel with the control section. An L-shaped shaft has one leg in the vessel upon which a float is mounted. The other leg extends through the opening in the housing into the control section. When a change in liquid level moves the float to a given level, the rotation of the shaft actuates a control element, such as an electrical switch, mounted in the control section of the housing. Two sealing elements made of a material, such as Teflon, that has a low coefficient of friction and is corrosion resistant support the shaft for rotation so that the switch assembly will operate for extended periods in the vessel with little, if any, increase in the force required to rotate the shaft.
Inventors
- 👤 John E Pottharst Jr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 17:06
CPC Classifications
H; H01; H01H; H01H35/00; H01H35/18
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
266 words
A liquid level control assembly especially adapted for use in a vessel containing a liquid or vapor that may be corrosive or tends to cause scale deposits, comprising a housing, adapted to be mounted on a vessel, having a control section and an opening connecting the inside of the vessel with the control section, a control mounted in the control section of the housing, a shaft extending through the opening in the housing such that the shaft extends into the vessel and into the housing control section, means mounted on the shaft in the control section to actuate the control upon rotation of the shaft and a float attached to the shaft inside the vessel to float on the surface of the liquid to rotate the shaft and actuate the control when the liquid in the vessel reaches a given level, first and second spaced apart sealing means located in the opening to respectively prevent flow from the vessel through the opening and from the opening into the control section of the housing, said first and second sealing means supporting the shaft for rotation within the housing opening substantially free from frictional contact of the shaft with the housing, said sealing means being of a material that has a coefficient of friction substantially that of polytetrafluoroethylene and that will not corrode when exposed to the liquid and vapor in the vessel so that the frIctional resistance of said sealing means to rotation of the shaft will remain substantially constant even though the shaft and sealing element are exposed to corrosive or scale forming liquids and vapors.
Claim 2
Dependent Claim
266 words
A liquid level control assembly especially adapted for use in a vessel containing a liquid or vapor that may be corrosive or tends to cause scale deposits, comprising a housing, adapted to be mounted on a vessel, having a control section and an opening connecting the inside of the vessel with the control section, a control mounted in the control section of the housing, a shaft extending through the opening in the housing such that the shaft extends into the vessel and into the housing control section, means mounted on the shaft in the control section to actuate the control upon rotation of the shaft and a float attached to the shaft inside the vessel to float on the surface of the liquid to rotate the shaft and actuate the control when the liquid in the vessel reaches a given level, first and second spaced apart sealing means located in the opening to respectively prevent flow from the vessel through the opening and from the opening into the control section of the housing, said first and second sealing means supporting the shaft for rotation within the housing opening substantially free from frictional contact of the shaft with the housing, said sealing means being of a material that has a coefficient of friction substantially that of polytetrafluoroethylene and that will not corrode when exposed to the liquid and vapor in the vessel so that the frIctional resistance of said sealing means to rotation of the shaft will remain substantially constant even though the shaft and sealing element are exposed to corrosive or scale forming liquids and vapors.
Claim 3
Dependent Claim
207 words
The liquid level control assembly of claim 1 in which the shaft is generally L-shaped and has first and second legs, the first leg of the shaft extends into the housing, and the float is attached to the second leg, the first leg of the shaft having a transverse groove with a flat bottom surface at a predetermined angular relationship with the longitudinal axis of the second leg of the shaft, and in which said actuating means includes a collar mounted on said shaft over the groove, the collar being radially split on one side, a tapped hole extending from one side of the split parallel to the flat surface on the shaft, a hole extending from the other side of the split with its longitudinal axis coinciding with the longitudinal axis of the tapped hole, a locking screw extending through the hole and threadedly engaging the tapped hole, said axes of the hole and tapped hole being spaced from the shaft such that the locking screw and the flat surface on the shaft will coact to hold the screw and the shaft in fixed angular relationship so that the locking screw will actuate the control each time the float rotates the shaft to a predetermined position.
Claim 4
Dependent Claim
92 words
The liquid level control assembly of claim 1 further provided with a thrust bushing of a corrosion-resistant material having a low coefficient of friction, such as polytetrafluoroethylene, mounted on the first leg of the shaft between the float and the housing and means holding the bushing against movement axially of the shaft and in position on the shaft to engage the inside portion of the housing and hold the shaft against axial movement toward the housing with a minimal increase in the frictional forces resisting rotation of the shaft by the float.
Claim 5
Dependent Claim
66 words
The liquid level control assembly of claim 1 further provided with a tattle-tale hole in the housing that connects the shaft opening between the first and second sealing elements with the outside of the housing so that corrosive liquid leaking through said first sealing element will flow out of the housing through the tattle-tale hole and indicate to an observer that the first seal is leaking.
Claim 6
Dependent Claim
16 words
The liquid level control assembly of claim 1 in which the control is an electrical switch.
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) | 1975-08-22 | 1976-02-21 | 1976-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-22 | 1980-02-21 | 1980-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-22 | 1984-02-21 | 1984-08-22 | $7700.00 | Window Closed / Lapsed |