US4234330A
Expired / Lapsed
US
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Process of making cellulated glass beads
Assignee: BFG Glassgroup GIE
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Filing: 1979-08-15
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Granted: 1980-11-18
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Expires: 1999-08-15
Abstract
Abstract A process of making cellulated glass beads by forming a mixture comprising glass particles and cellulating agent into nodules, heat treating the nodules to cause fusion of glass and evolution of gas from the cellulating agent to form cellulated glass beads, and cooling the cellulated glass beads to a rigid condition. The cellulating agent utilized has the characteristic of creating expansion forces due to the evolution of gas during heat treatment which are generated wholly or mainly while the glass viscosity is within the range 10 6 .5 to 10 8 .5 poises. The heat treatment is carried out with a quantity of cellulating agent at a maximum cellulation temperature which is not above the temperature corresponding with a glass viscosity of 10 5 .5 poises and for a time such that the beads immediately following the heat treatment are populated with cells, and after cooling have a bulk density of not more than 0.5 g/cm 3 and a water-permeability of less than 15% by volume determined by the immersion test herein specified.
Inventors
- 👤 Pierre Taupin
- 👤 Michel Glineur
- 👤 Jean Florean
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 23:01
CPC Classifications
C; C03; C03B; C03B19/00; C03B19/10; C03B19/108; C03B19/1085; C03C; C03C11/00; C03C11/002; C03C11/007
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
196 words
A process of making cellulated glass beads of fully cellulated structure by forming a mixture comprising glass particles and cellulating agent into nodules, heat treating the nodules to cause fusion of glass and evolution of gas from the cellulating agent to form cellulated glass beads, and cooling the cellulated glass beads to a rigid condition, the improvement which comprises the steps of utilizing as the cellulating agent an agent having the characteristic of creating expansion forces due to the evolution of gas during heat treatment which are generated wholly or mainly while the glass viscosity is within the range 10 6 .5 to 10 8 .5 poises, and carrying out the heat treatment with a quantity of cellulating agent at a maximum cellulation temperature which is not above the temperature corresponding with a glass viscosity of 10 5 .5 poises and for a time such that the beads immediately following the heat treatment are populated with cells throughout the volume thereof including the exterior surface thereof, and after cooling have a bulk density of not more than 0.5 g/cm 3 and a water-permeability of less than 15% by volume determined by the immersion test herein specified.
Claim 2
Dependent Claim
196 words
A process of making cellulated glass beads of fully cellulated structure by forming a mixture comprising glass particles and cellulating agent into nodules, heat treating the nodules to cause fusion of glass and evolution of gas from the cellulating agent to form cellulated glass beads, and cooling the cellulated glass beads to a rigid condition, the improvement which comprises the steps of utilizing as the cellulating agent an agent having the characteristic of creating expansion forces due to the evolution of gas during heat treatment which are generated wholly or mainly while the glass viscosity is within the range 10 6 .5 to 10 8 .5 poises, and carrying out the heat treatment with a quantity of cellulating agent at a maximum cellulation temperature which is not above the temperature corresponding with a glass viscosity of 10 5 .5 poises and for a time such that the beads immediately following the heat treatment are populated with cells throughout the volume thereof including the exterior surface thereof, and after cooling have a bulk density of not more than 0.5 g/cm 3 and a water-permeability of less than 15% by volume determined by the immersion test herein specified.
Claim 3
Dependent Claim
35 words
A process as defined in claim 1 wherein the cellulating agent is selected so that the evolution of gas therefrom occurs wholly or mainly while the glass has a viscosity below 10 7 .65 poises.
Claim 4
Dependent Claim
41 words
A process as defined in claim 1 or 2 wherein the cellulating agent is selected so that the evolution of gas therefrom occurs wholly or mainly after all or substantially all of the glass particles mixed therewith have reached sintering temperature.
Claim 5
Dependent Claim
36 words
A process as defined in claim 1 or 2 wherein the cellulating temperature of the heat treatment is within the range which corresponds to a glass viscosity of 10 5 .5 to 10 7 .5 poises.
Claim 6
Dependent Claim
19 words
A process as defined in claim 1 wherein the cellulating agent is initially in particle form in the nodules.
Claim 7
Dependent Claim
29 words
A process as defined in claim 5 wherein the mean size of the particles of cellulating agent is approximately the same as the mean size of the glass particles.
Claim 8
Dependent Claim
25 words
A process as defined in claim 1 or 5 wherein the cellulating agent comprises a compound which decomposes to give rise to evolution of gas.
Claim 9
Dependent Claim
16 words
A process as defined in claim 7 wherein calcium carbonate is used as the cellulating agent.
Claim 10
Dependent Claim
28 words
A process as defined in claim 8 wherein the quantity of calcium carbonate present is from 1.7 to 2.7% by weight based on the weight of the glass.
Claim 11
Dependent Claim
36 words
A process as defined in claim 5 wherein the initial nodules contain glass particles and particulate cellulating agent and water is used as the sold medium for causing such particulate ingredients to cohere in nodule form.
Claim 12
Dependent Claim
27 words
A process as defined in claim 10 wherein the initial mixture contains 10 to 20% by weight of water based on the total weight of the mixture.
Claim 13
Dependent Claim
22 words
A process as defined in claim 1 wherein the beads are kept in rolling contact with each other during their heat treatment.
Claim 14
Dependent Claim
17 words
A process as defined in claim 12 wherein the heat treatment is performed in a rotating furnace.
Claim 15
Dependent Claim
20 words
A process as defined in claim 1 wherein the beads are heated in loose condition in a hot gas stream.
Claim 16
Dependent Claim
116 words
A process as defined in claim 1 wherein the heat treatment of the mixture is performed in two stages in the first of which nodules of such mixture, while free from rubbing contact with each other, are heated sufficiently to cause sintering of glass particles but insufficiently to cause expansion of such nodules, and in the second of which stages nodules of the mixture which has been heated in said first stage are heated in a cellulating furnace, while in free relative movement, to a higher temperature to allow cellulation to take place, the cellulating furnace having a maximum temperature which does not exceed a temperature corresponding with a glass viscosity of 10 5 .5 poises.
Claim 17
Dependent Claim
33 words
A process as defined in claim 15 wherein the temperature of the cellulating furnace is within the range corresponding to a glass viscosity range of 10 5 .5 to 10 7 .5 poises.
Claim 18
Dependent Claim
42 words
A process as defined in claim 15 or 16 wherein the heating of nodules in said first stage is performed in a furnace maintained at substantially constant temperature and so that the heating curve is substantially the same for all the nodules.
Claim 19
Dependent Claim
46 words
A process as defined in claim 17 wherein said first stage heat treatment is performed by transporting said nodules on a conveyor through a tunnel furnace at a temperature in a range corresponding with a glass viscosity range of 10 7 .65 to 10 11 poises.
Claim 20
Dependent Claim
32 words
A process as defined in claim 18 wherein the tunnel furnace is at a temperature in the range corresponding to a glass viscosity range of 10 8 .5 to 10 11 poises.
Claim 21
Dependent Claim
19 words
A process as defined in claim 1 or 15 wherein the beads are annealed after leaving the cellulating furnace.
Claim 22
Dependent Claim
22 words
A process as defined in claim 20 wherein the beads are annealed during transportation thereof through a tunnel furnace by a conveyor.
Claim 23
Dependent Claim
25 words
A process as defined in claim 1 or 15 wherein the beads are cooled or allowed to cool rapidly following cellulation in the cellulation furnace.
Claim 24
Dependent Claim
19 words
A process as defined in claim 15 wherein prior to the heat treatment the nodules are subjected to crushing.
Claim 25
Dependent Claim
34 words
A process as defined in claim 15 wherein the nodules are crushed between sintering and cellulation stages of the heat treatment and while the nodules are in the temperature range 250° to 300° C.
Claim 26
Dependent Claim
41 words
A process as defined in claim 24 wherein following a sintering stage of the heat treatment the nodules are rapidly cooled to induce fracturing or fissuring thereof and they are then crushed before undergoing the cellulation stage of the heat treatment.
Claim 27
Dependent Claim
33 words
A process as defined in claim 1 or 15 wherein the nodules before undergoing the cellulation stage of the heat treatment are wholly or mainly in the size range 1.5 to 15 mm.
Claim 28
Dependent Claim
28 words
A process as defined in claim 1 or 15 wherein the glass particles in the initial mixture have a specific surface of at least 3000 cm 2 /g.
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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) | 1983-11-18 | 1984-05-19 | 1984-11-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1987-11-18 | 1988-05-19 | 1988-11-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1991-11-18 | 1992-05-19 | 1992-11-18 | $7700.00 | Window Closed / Lapsed |