US3976728A
Expired / Lapsed
US
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Refractory heat insulating materials
Assignee: Foseco International Ltd
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Filing: 1975-04-24
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Granted: 1976-08-24
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Expires: 1995-04-24
Abstract
Abstract A shaped article of refractory heat insulating material is made by forming a mixture of inorganic refractory fibrous material and a binding agent which may be soluble or dispersible in a suitable liquid medium, forming the mixture to the desired shape, drying the shape in a first drying step, impregnating the so-dried shape in a second drying step, one of the drying steps being an homogeneous drying step and the other being a non-homogeneous drying step.
Inventors
- 👤 Peter Frederick Hawthorne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:00
CPC Classifications
C; C04; C04B; C04B35/00; C04B35/71; C04B35/74; C04B35/76; C04B28/00; C04B35/01; C04B35/14; C04B35/622; C04B35/62204; C04B35/62213; C04B35/626; C04B35/63; C04B35/6303; C04B35/6306; C04B35/6316; C04B35/632; C04B35/6325; C04B35/66; C04B35/78; C04B35/80; C04B35/82; C04B2235/00; C04B2235/02; C04B2235/30; C04B2235/32; C04B2235/3201; C04B2235/34; C04B2235/3409; C04B2235/3418; C04B2235/3427; C04B2235/50; C04B2235/52; C04B2235/5208; C04B2235/5216; C04B2235/522; C04B2235/5224; C04B2235/5228; C04B2235/5232; C04B2235/5236; C04B2235/524; C04B2235/5244; C04B2235/5248; C04B2235/60; C04B2235/606; C04B2235/616
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
147 words
A method of making a shaped article of refractory heat insulating material which comprises forming a homogeneous wet mixture of inorganic refractory fibrous material and binding agent which may be soluble or dispersible in a suitable liquid medium, forming the mixture to the desired shape, drying the shape in a first drying step, impregnating the so-dried shape with binding agent, and drying the shape in a second drying step, one of the drying steps being a drying step which when applied to a homogeneous wet mixture of said fibre and said binder gives a dry product having mechanical properties which are homogeneous between opposed surfaces of the product and the other being a drying step which, when applied to a homogeneous wet mixture of said fibre and said binder, gives a dried product the mechanical properties of which are not homogeneous between opposed surfaces of the product.
Claim 2
Independent Claim
147 words
A method of making a shaped article of refractory heat insulating material which comprises forming a homogeneous wet mixture of inorganic refractory fibrous material and binding agent which may be soluble or dispersible in a suitable liquid medium, forming the mixture to the desired shape, drying the shape in a first drying step, impregnating the so-dried shape with binding agent, and drying the shape in a second drying step, one of the drying steps being a drying step which when applied to a homogeneous wet mixture of said fibre and said binder gives a dry product having mechanical properties which are homogeneous between opposed surfaces of the product and the other being a drying step which, when applied to a homogeneous wet mixture of said fibre and said binder, gives a dried product the mechanical properties of which are not homogeneous between opposed surfaces of the product.
Claim 3
Dependent Claim
36 words
A method as in claim 1 wherein the homogeneous drying step is carried out by microwave heating or dielectric heating and wherein said non-homogeneous drying step is carried out by heating the article with hot air.
Claim 4
Dependent Claim
16 words
A method according to claim 1 wherein the first drying step is said one drying step.
Claim 5
Dependent Claim
17 words
A method according to claim 1 wherein the binder is colloidal alumina sol, or colloidal silica sol.
Claim 6
Dependent Claim
17 words
A method according to claim 1 wherein the binder is ethyl silicate, sodium silicate or potassium silicate.
Claim 7
Dependent Claim
15 words
A method according to claim 1 wherein the binder is a metallic phosphate or borate.
Claim 8
Dependent Claim
38 words
A method according to claim 1 wherein the inorganic fibre is selected from alumino silicate fibre, calcium silicate, asbestos, alumina, silica, zirconia, boron nitride, silicon carbide or carbon firbres or a mixture of one or more of these.
Claim 9
Dependent Claim
15 words
A method according to claim 7 wherein a proportion of the fibres are metal fibres.
Claim 10
Dependent Claim
14 words
A method according to claim 1 wherein the mixture comprises a particulate refractory filler.
Claim 11
Dependent Claim
31 words
A method according to claim 1 wherein after the two drying steps the articles are further improved by drying at a temperature between 300° - 900°C for 1/2 - 24 hours.
Claim 12
Dependent Claim
33 words
A method according to claim 1 wherein the ingredients of the mixture and the conditions of the method are selected to give a material of final density 0.30 to 0.9 gm/cm 3 .
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) | 1979-08-24 | 1980-02-23 | 1980-08-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-24 | 1984-02-23 | 1984-08-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-24 | 1988-02-23 | 1988-08-24 | $7700.00 | Window Closed / Lapsed |