Patent US4313830A successfully refreshed from Google Patents.
US4313830A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for increasing the cross-flow microfiltration fluxes of waste waters containing suspended solids and/or emulsified oil
Assignee: T-HYDRONAUTICS Inc A CORP OF TX
•
Filing: 1980-05-23
•
Granted: 1982-02-02
•
Expires: 2000-05-23
Abstract
Abstract A method for increasing the cross-flow microfiltration fluxes of waste waters containing suspended solids and/or emulsified oil through microporous thermoplastic tubes by including therein a calcium compound selected from Ca(OH)2 or CaSO4. The calcium compound is present in the waste waters in an amount ranging from above the solubility limit of the compound to about forty (40) percent by weight of the waste waters. The Ca(OH)2 can be added directly to the waste water. The CaSO4 can be included by reacting H2SO4 and Ca(OH)2 in the waste waters to form CaSO4 in situ. Alternatively, wet CaSO4 can be formed by reacting H2SO4 with Ca(OH)2 outside the water and then added to to the waste waters in the required amount.
Inventors
- 👤 Marshall P. Tulin
- 👤 John E. Santo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:48
CPC Classifications
B; B01; B01D; B01D17/00; B01D17/08; B01D17/085; B01D61/00; B01D61/14; B01D61/147; B01D2315/00; B01D2315/10
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
160 words
A method for increasing the cross-flow microfiltration fluxes of waste waters containing suspended solids and/or emulsified oil comprising the steps of: (a) adding sulfuric acid to waste waters in an amount sufficient to lower the pH of said waste waters to an acidic value, (b) adding calcium hydroxide to said acidified waste waters in an amount sufficient to form calcium sulfate in situ in the waste water in an amount ranging from above the solubility limit of said calcium sulfate to about forty (40) percent by weight of said waste waters and, filtering said waste waters containing said calcium sulfate by cross-flow microfiltration through microporous thermoplastic tubes, wherein said microporous tubes: (i) are made of an extrudable thermoplastic composition selected from the group consisting of nylon and polyethylene; (ii) have walls about one (1) millimeter in thickness; (iii) have a dominant pore size ranging from one (1) to ten (10) microns; and (iv) having a porosity of about 65 percent.
Claim 2
Independent Claim
160 words
A method for increasing the cross-flow microfiltration fluxes of waste waters containing suspended solids and/or emulsified oil comprising the steps of: (a) adding sulfuric acid to waste waters in an amount sufficient to lower the pH of said waste waters to an acidic value, (b) adding calcium hydroxide to said acidified waste waters in an amount sufficient to form calcium sulfate in situ in the waste water in an amount ranging from above the solubility limit of said calcium sulfate to about forty (40) percent by weight of said waste waters and, filtering said waste waters containing said calcium sulfate by cross-flow microfiltration through microporous thermoplastic tubes, wherein said microporous tubes: (i) are made of an extrudable thermoplastic composition selected from the group consisting of nylon and polyethylene; (ii) have walls about one (1) millimeter in thickness; (iii) have a dominant pore size ranging from one (1) to ten (10) microns; and (iv) having a porosity of about 65 percent.
Claim 3
Dependent Claim
36 words
The method of claim 1 wherein said sulfuric acid is added in an amount sufficient to lower the pH of said waste waters to about 1 and the calcium hydroxide raises the pH to approximately 9.
Claim 4
Dependent Claim
29 words
The method of claim 1 wherein said amount of calcium sulfate ranges from above the solubility limit thereof to about ten (10) percent by weight of said waste waters.
Claim 5
Dependent Claim
29 words
The method of claim 3 wherein said amount of calcium sulfate ranges from above the solubility limit thereof to about three (3) percent by weight of said waste waters.
Claim 6
Independent Claim
135 words
A method for increasing the cross-flow microfiltration fluxes of waste waters containing suspended solids and/or emulsified oil comprising the steps of: (a) forming wet calcium sulfate by reacting sulfuric acid with calcium hydroxide; (b) adding said wet calcium sulfate to waste waters in an amount ranging from above the solubility limit of said calcium sulfate to about forty (40) percent by weight of said waste waters and, filtering said waste waters containing said calcium sulfate by cross-flow microfiltration through microporous thermoplastic tubes, wherein said microporous tubes: (i) are made of an extrudable thermoplastic composition selected from the group consisting of nylon and polyethylene; (ii) have walls about one (1) millimeter in thickness; (iii) have a dominant pore size ranging from one (1) to ten (10) microns; and (iv) having a porosity of about 65 percent.
Claim 7
Independent Claim
135 words
A method for increasing the cross-flow microfiltration fluxes of waste waters containing suspended solids and/or emulsified oil comprising the steps of: (a) forming wet calcium sulfate by reacting sulfuric acid with calcium hydroxide; (b) adding said wet calcium sulfate to waste waters in an amount ranging from above the solubility limit of said calcium sulfate to about forty (40) percent by weight of said waste waters and, filtering said waste waters containing said calcium sulfate by cross-flow microfiltration through microporous thermoplastic tubes, wherein said microporous tubes: (i) are made of an extrudable thermoplastic composition selected from the group consisting of nylon and polyethylene; (ii) have walls about one (1) millimeter in thickness; (iii) have a dominant pore size ranging from one (1) to ten (10) microns; and (iv) having a porosity of about 65 percent.
Claim 8
Dependent Claim
30 words
The method of claim 5 wherein said amount of wet calcium sulfate ranges from about the solubility limit thereof to about ten (10) percent by weight of said waste waters.
Claim 9
Dependent Claim
30 words
The method of claim 6 wherein said amount of wet calcium sulfate ranges from above the solubility limit thereof to about three (3) percent by weight of said waste waters.
Claim 10
Dependent Claim
15 words
The method of claim 1 or 5 wherein said waste waters are laundry waste waters.
Claim 11
Dependent Claim
19 words
The method of claim 1 or 5 where said waste waters are oily waste waters from a metal-cutting operation.
Claim 12
Dependent Claim
27 words
The method of claim 1 or 5 wherein said calcium hydroxide is selected from the group consisting of calcium hydrate, hydrated lime, caustic lime and slaked lime.
References Cited (Backward Citations)
US3445000A
Cited
US3236768A
Cited
US3310175A
Cited
US3259567A
Cited
US3398088A
Cited
US3556992A
Cited
US3996131A
Cited
US3733265A
Cited
US3799806A
Cited
US3856569A
Cited
US4081369A
Cited
US4014787A
Cited
JPS5145450A
Cited
US3976569A
Cited
US4155845A
Cited
US4207183A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-02-01 | 1985-08-03 | 1986-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-02-01 | 1989-08-03 | 1990-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-02-01 | 1993-08-03 | 1994-02-02 | $7700.00 | Window Closed / Lapsed |