US4077227A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of freezing liquid material in which agglomeration is inhibited
Assignee: University of Minnesota System
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Filing: 1976-11-12
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Granted: 1978-03-07
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Expires: 1996-11-12
Abstract
Abstract The liquid material to be frozen is separated into successive drops, each of which is subjected to an electric field of sufficient strength so as to induce on each drop an electric charge, the charges all being of the same polarity. The charged drops are sequentially directed at a controlled rate onto the surface of a cryogenic liquid where they momentarily float while being changed to a solid frozen state. During this interval the electric charges, being of like polarity, produce repulsive forces in accordance with Coulomb's Law which keep the drops apart so that they freeze and sink as individual pellets. The lack of agglomeration enables the pellets to be more rapidly and uniformly frozen and more rapidly and uniformly thawed for use at a later time. In this way, substances vulnerable to deterioration can be preserved for prolonged periods.
Inventors
- 👤 E. Virgil Larson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 23:01
CPC Classifications
A; A01; A01N; A01N1/00; A01N1/10; A01N1/16; A01N1/168; A01N1/14; A01N1/142; A01N1/144; A01N1/145; F; F25; F25C; F25C1/00; F25D; F25D3/00; F25D3/10
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
38 words
A method of freezing a quantity of liquid material comprising the steps of separating said quantity of material into individual drops, applying an electric charge of one polarity to said drops, and freezing said drops while still charged.
Claim 2
Independent Claim
38 words
A method of freezing a quantity of liquid material comprising the steps of separating said quantity of material into individual drops, applying an electric charge of one polarity to said drops, and freezing said drops while still charged.
Claim 3
Dependent Claim
16 words
The method of claim 1 in which said material is a biological substance to be preserved.
Claim 4
Dependent Claim
14 words
The method of claim 2 in which the biological substance is blood or semen.
Claim 5
Dependent Claim
17 words
The method of claim 1 in which said charging and freezing steps are performed at spaced locations.
Claim 6
Dependent Claim
24 words
The method of claim 4 in which said charging location is at one elevation and said freezing location is at a lower elevation therebeneath.
Claim 7
Dependent Claim
35 words
The method of claim 5 in which said charging step is performed with an electric field and said freezing step is performed with a cryogenic liquid so as to freeze said drops into solid pellets.
Claim 8
Dependent Claim
19 words
The method of claim 6 in which said drops are delivered to said cryogenic liquid at a controlled rate.
Claim 9
Dependent Claim
26 words
The method of claim 7 in which said drops are permitted to fall gravitationally from said one elevation to said lower elevation at said controlled rate.
Claim 10
Dependent Claim
19 words
The method of claim 8 in which said rate is selected in accordance with the size of said drops.
Claim 11
Dependent Claim
30 words
The method of claim 9 in which the strength of the electric field utilized in charging said drops is increased for larger size drops when being delivered at given rate.
Claim 12
Dependent Claim
33 words
The method of claim 9 in which the strength of the electric field utilized in charging said drops is increased for a greater delivery rate when the size of drop remains the same.
Claim 13
Dependent Claim
29 words
The method of claim 9 in which the strength of the electric field utilized in charging said drops is increased as the drop size and delivery rate is increased.
Claim 14
Dependent Claim
32 words
The method of claim 9 in which the strength of the electric field utilized in charging said drops is increased when either the size of drops or their delivery rate is increased.
Claim 15
Dependent Claim
60 words
The method of claim 9 in which the strength of the electric field utilized in charging said drops is selected so that the charges applied to the drops maintain the charged drops, when floating on the surface of the cryogenic liquid, separated and which does not cause the floating drops to bounce upwardly from the surface of the cryogenic liquid.
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US3162019A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-03-06 | 1981-09-05 | 1982-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-03-06 | 1985-09-05 | 1986-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-03-06 | 1989-09-05 | 1990-03-07 | $7700.00 | Window Closed / Lapsed |