Patent US4097682A successfully refreshed from Google Patents.
US4097682A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Means for protecting underground electrical equipment from thermal runaway
Assignee: Electric Power Research Institute
•
Filing: 1976-08-27
•
Granted: 1978-06-27
•
Expires: 1996-08-27
Abstract
Abstract Underground electrical equipment such as a transformer or cable is prevented from thermal runaway by back-filling the trench in which it is laid with a soil which includes water entrapped in highly water-absorbent hydrophilic polymeric gel particles soaked with water. The water-soaked particles preferably are coated with a water-impermeable film. The water may also be entrapped in liquid form in small balloon-like containers. Also, a water impermeable sheath may be formed around the back-fill soil to minimize evaporation from the particles.
Inventors
- 👤 Elijah R. Perry
- 👤 Meredith J. Angwin
- 👤 Mario Rabinowitz
- 👤 John F. Shimshock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 17:26
CPC Classifications
H; H02; H02G; H02G9/00; H02G9/02
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
66 words
In a method for protecting underground heat-generating electrical equipment from thermal runaway, the steps of (a) laying the equipment in an open trench, (b) back-filling the trench with soil in which water-absorbent particles are dispersed, said particles comprising a water-swellable, hydrophilic polymer gel material capable of swelling to absorb at least ten times its own weight of water, and (c) soaking said absorbent particles with water.
Claim 2
Dependent Claim
66 words
In a method for protecting underground heat-generating electrical equipment from thermal runaway, the steps of (a) laying the equipment in an open trench, (b) back-filling the trench with soil in which water-absorbent particles are dispersed, said particles comprising a water-swellable, hydrophilic polymer gel material capable of swelling to absorb at least ten times its own weight of water, and (c) soaking said absorbent particles with water.
Claim 3
Dependent Claim
15 words
The method of claim 1 in which said soaking step is performed prior to back-filling.
Claim 4
Dependent Claim
20 words
The method of claim 1 in which said soaking step is performed by pouring water into the trench during back-filling.
Claim 5
Dependent Claim
21 words
The method of claim 1 in which said soaking step is performed by pouring water into the trench subsequent to back-filling.
Claim 6
Dependent Claim
40 words
The method of claim 1 in which after soaking, said absorbent particles are coated with a substantially water-impermeable film of sufficient strength to withstand mixing with soil and thereafter said coated particles are dispersed in said soil prior to back-filling.
Claim 7
Dependent Claim
18 words
The method of claim 1 in which said absorbent particles are dispersed into said soil prior to back-filling.
Claim 8
Dependent Claim
31 words
The method of claim 1 in which, after backfilling and swelling, a water impermeable sheet is placed over the back-filled trench to reduce evaporation of water from said soaked absorbent particles.
Claim 9
Dependent Claim
17 words
The method of claim 1 in which said absorbent particles and soil are premixed prior to back-filling.
Claim 10
Dependent Claim
26 words
The method of claim 1 in which said absorbent particles are deposited as a concentrated layer around the electric equipment without premixing with substantial back-fill soil.
Claim 11
Dependent Claim
94 words
In a method for protecting underground electrical equipment from thermal runaway, the steps of (a) digging a trench for the equipment, (b) depositing an elongated impermeable lower sheet with upwardly extending sidewalls and a bottom wall to conform to the trench, (c) laying the equipment in the interior of the lower sheet, (d) back-filling around the equipment with soil in which water-absorbent particles are dispersed comprising a water-swellable hydrophilic polymer gel material capable of swelling to absorb at least ten times its own weight of water, and (e) soaking said absorbent particles with water.
Claim 12
Dependent Claim
94 words
In a method for protecting underground electrical equipment from thermal runaway, the steps of (a) digging a trench for the equipment, (b) depositing an elongated impermeable lower sheet with upwardly extending sidewalls and a bottom wall to conform to the trench, (c) laying the equipment in the interior of the lower sheet, (d) back-filling around the equipment with soil in which water-absorbent particles are dispersed comprising a water-swellable hydrophilic polymer gel material capable of swelling to absorb at least ten times its own weight of water, and (e) soaking said absorbent particles with water.
Claim 13
Dependent Claim
31 words
The method of claim 10 in which an impermeable top sheet is placed over the upper surface of said back-filled soil to reduce evaporation of water from said soaked absorbent particles.
Claim 14
Dependent Claim
24 words
The method of claim 11 in which the upper edges of said bottom sheet are sealed with the side edges of said top sheet.
Claim 15
Dependent Claim
52 words
An underground electrical equipment structure protected from thermal runaway comprising, (a) the equipment, (b) back-fill soil around said electrical equipment, and (c) water-soaked absorbent particles dispersed in said soil, said particles comprising a water-swellable hydrophilic polymer gel material capable of swelling to absorb at least ten times its own weight of water.
Claim 16
Dependent Claim
52 words
An underground electrical equipment structure protected from thermal runaway comprising, (a) the equipment, (b) back-fill soil around said electrical equipment, and (c) water-soaked absorbent particles dispersed in said soil, said particles comprising a water-swellable hydrophilic polymer gel material capable of swelling to absorb at least ten times its own weight of water.
Claim 17
Dependent Claim
23 words
The structure of claim 13 together with an elongated impermeable top sheet disposed over the upper surface of said back-filled soil and equipment.
Claim 18
Dependent Claim
29 words
The structure of claim 13 together with an elongate impermeable lower sheet with upwardly extending sidewalls and a bottom wall disposed below and to the sides of said equipment.
Claim 19
Dependent Claim
25 words
The structure of claim 13 in which the upper side edges of said upper sheet are sealed to the side edges of said top sheet.
Claim 20
Dependent Claim
17 words
The structure of claim 13 in which said absorbent particles form a concentrated layer around said equipment.
Claim 21
Dependent Claim
35 words
The structure of claim 13 in which said absorbent particles are present in a gradation of sizes sufficient for void spaces among the larger particles to be filled to a significant extent with smaller particles.
Claim 22
Dependent Claim
12 words
The structure of claim 13 in which said equipment comprises electrical cable.
Claim 23
Dependent Claim
66 words
In a method for forming particles of high thermal conductivity suitable for dispersion in soil to increase its thermal conductivity, the steps of (a) soaking absorbent particles with water said particles comprising a material capable of absorbing at least 10 times its own weight of water, and (b) coating said soaked absorbent particles with a substantially water-impermeable film of sufficient strength to withstand mixing with soil.
Claim 24
Dependent Claim
66 words
In a method for forming particles of high thermal conductivity suitable for dispersion in soil to increase its thermal conductivity, the steps of (a) soaking absorbent particles with water said particles comprising a material capable of absorbing at least 10 times its own weight of water, and (b) coating said soaked absorbent particles with a substantially water-impermeable film of sufficient strength to withstand mixing with soil.
Claim 25
Dependent Claim
31 words
The method of using the particles formed in claim 20 to increase the thermal conductivity of soil comprising the step of (c) mixing said coated particles with a volume of soil.
Claim 26
Dependent Claim
37 words
The method of claim 20 in which an underfilm compatible with said absorbent particles is coated onto said particles prior to coating of said soaked absorbent particles, said water-impermeable film and underfilm being formed of different materials.
Claim 27
Dependent Claim
59 words
A product of high thermal conductivity suitable for dispersion in soil to increase its thermal conductivity comprising, (a) absorbent particles soaked with water, said particles comprising a material capable of absorbing at least 10 times its own weight of water, and (b) a substantially water-impermeable film surrounding each of said particles of sufficient strength to withstand mixing with soil.
Claim 28
Dependent Claim
59 words
A product of high thermal conductivity suitable for dispersion in soil to increase its thermal conductivity comprising, (a) absorbent particles soaked with water, said particles comprising a material capable of absorbing at least 10 times its own weight of water, and (b) a substantially water-impermeable film surrounding each of said particles of sufficient strength to withstand mixing with soil.
Claim 29
Dependent Claim
16 words
The product of claim 23 in which said soaked particle material comprises a hydrophilic polymeric gel.
Claim 30
Dependent Claim
16 words
The product of claim 23 in which said water-impermeable film is formed of a polymeric material.
Claim 31
Dependent Claim
27 words
The product of claim 23 in which an intermediate underfilm is present between said water impermeable film and absorbent particles, said films being formed of different materials.
Claim 32
Dependent Claim
43 words
In a method for protecting underground electrical equipment from thermal runaway, the steps of (a) laying the equipment in an open trench, (b) back-filling the trench with soil and (c) placing a plurality of water-filled bags into the back-fill soil around the equipment.
Claim 33
Dependent Claim
43 words
In a method for protecting underground electrical equipment from thermal runaway, the steps of (a) laying the equipment in an open trench, (b) back-filling the trench with soil and (c) placing a plurality of water-filled bags into the back-fill soil around the equipment.
Claim 34
Dependent Claim
22 words
The method of claim 27 in which at least 20% of said bags have an effective diameter of at least 0.5 cm.
Claim 35
Dependent Claim
17 words
The method of claim 27 in which said bags are formed of a flexible substantially water-impermeable material.
Claim 36
Dependent Claim
33 words
An underground electrical equipment structure protected from thermal runaway comprising, (a) the equipment, (b) back-fill soil around said equipment, and (c) a plurality of water-filled bags in said back-fill soil around the equipment.
Claim 37
Dependent Claim
33 words
An underground electrical equipment structure protected from thermal runaway comprising, (a) the equipment, (b) back-fill soil around said equipment, and (c) a plurality of water-filled bags in said back-fill soil around the equipment.
Claim 38
Dependent Claim
23 words
The structure of claim 30 together with an elongated impermeable top sheet disposed over the upper surface of said back-filled soil and equipment.
Claim 39
Dependent Claim
29 words
The structure of claim 31 together with an elongate impermeable lower sheet with upwardly extending sidewalls and a bottom wall disposed below and to the sides of said equipment.
Claim 40
Dependent Claim
25 words
The structure of claim 32 in which the upper side edges of said upper sheet are sealed to the side edges of said top sheet.
References Cited (Backward Citations)
GB272189A
Cited
US2066323A
Cited
US3082111A
Cited
GB1116175A
Cited
FR1453592A
Cited
FR90088E
Cited
US3582533A
Cited
US3869562A
Cited
US3890613A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-06-26 | 1981-12-26 | 1982-06-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-26 | 1985-12-26 | 1986-06-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-26 | 1989-12-26 | 1990-06-27 | $7700.00 | Window Closed / Lapsed |