GB2318858A - A method of drying glaze in a UCV drying apparatus - Google Patents
A method of drying glaze in a UCV drying apparatus Download PDFInfo
- Publication number
- GB2318858A GB2318858A GB9622674A GB9622674A GB2318858A GB 2318858 A GB2318858 A GB 2318858A GB 9622674 A GB9622674 A GB 9622674A GB 9622674 A GB9622674 A GB 9622674A GB 2318858 A GB2318858 A GB 2318858A
- Authority
- GB
- United Kingdom
- Prior art keywords
- glaze
- article
- infra
- heater
- red
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 238000001035 drying Methods 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 title claims abstract description 23
- 238000000576 coating method Methods 0.000 claims abstract description 22
- 230000005855 radiation Effects 0.000 claims abstract description 21
- 230000003197 catalytic effect Effects 0.000 claims abstract description 20
- 239000011248 coating agent Substances 0.000 claims abstract description 20
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 8
- 238000010521 absorption reaction Methods 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 2
- 230000000694 effects Effects 0.000 abstract description 4
- 238000004519 manufacturing process Methods 0.000 description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000001301 oxygen Substances 0.000 description 4
- 229910052760 oxygen Inorganic materials 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 3
- 239000000919 ceramic Substances 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- BASFCYQUMIYNBI-UHFFFAOYSA-N platinum Chemical compound [Pt] BASFCYQUMIYNBI-UHFFFAOYSA-N 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 239000001273 butane Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000009472 formulation Methods 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 239000000383 hazardous chemical Substances 0.000 description 1
- 231100000206 health hazard Toxicity 0.000 description 1
- 150000002611 lead compounds Chemical class 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- OFBQJSOFQDEBGM-UHFFFAOYSA-N n-pentane Natural products CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 238000006213 oxygenation reaction Methods 0.000 description 1
- 229910052697 platinum Inorganic materials 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B3/00—Drying solid materials or objects by processes involving the application of heat
- F26B3/28—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun
- F26B3/30—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun from infrared-emitting elements
- F26B3/305—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun from infrared-emitting elements the infrared radiation being generated by combustion or combustion gases
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F26—DRYING
- F26B—DRYING SOLID MATERIALS OR OBJECTS BY REMOVING LIQUID THEREFROM
- F26B3/00—Drying solid materials or objects by processes involving the application of heat
- F26B3/28—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun
- F26B3/283—Drying solid materials or objects by processes involving the application of heat by radiation, e.g. from the sun in combination with convection
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Life Sciences & Earth Sciences (AREA)
- Microbiology (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Drying Of Solid Materials (AREA)
Abstract
A method of drying a coating of glaze applied to an article 15 wherein the coating of glaze is exposed to long-wave infra-red radiation supplied by catalytic infra-red heaters 12. The apparatus putting the method into effect comprises an elongate chamber 10 in which the catalytic infra-red heaters 12 are located and supports 14 upon which the article 15 may be supported. Means 16, 17 provide a flow of heated dry air through the chamber 10 to assist the drying process.
Description
Method of drying glaze and apparatus therefor.
The present invention relates to the production of glazed objects, in particular glazed ceramics articles, and to a method of drying a glaze applied to such articles.
It is usual to apply a glaze to ceramics articles and clay-ware as a final stage in the manufacture of such articles in order to enhance the item's appearance and durability. Many glazes have been traditionally based on lead compounds, however these glazes are becoming less widely used because of perceived or actual health hazards associated with such materials. The ceramics industry is increasingly adopting water-based glaze formulations which are less hazardous than the traditional materials but which can be problematic to apply correctly. The main problems encountered with water-based glazes is that they do not "flow-out" particularly well to form a smooth and uniform coating and they also tend to take a long time to cure using conventional methods of drying such as passing the glazed articles through hot air ovens.
The problems of achieving good glaze flow can be alleviated by applying a relatively thin coating of glaze, drying it and then applying further thin coats of glaze to build up the desired thickness of glaze.
Each coating needs to be dried before applying the next and so the time taken to dry each coating becomes a very important factor in determining the total time taken to complete the application of a glaze. The timing of each production stage is a critical factor in determining the throughput of a mass-production operation for the manufacture of clay-ware and so it is highly desirable to reduce the time taken to apply and dry glaze.
It is an object of the present invention to provide an improved method of drying coatings of glaze.
According to the invention a method of drying a coating of glaze applied to an article comprises exposing said coating to long-wave infra-red radiation supplied by a catalytic infra-red heater. The wavelength of radiation emitted by catalytic heaters is very well matched to the absorption bands of water molecules and so it is especially suitable for drying water-based glazes. The preferential absorption of this type of radiation results in much shorter drying times compared with the use of more conventional heating methods such as hot air or radiant panels.
A catalytic infra-red heater in this specification means a heating device which emits long-wave infra-red radiation as a result of reacting an organic gas with oxygen at a catalyst surface to produce water vapour and carbon dioxide. The catalyst, usually platinum-based, is usually carried on a mesh or other porous support and arranged to form a panel to which the gas, commonly butane or natural gas, is fed. The preferred type of catalytic infra-red heater is naturally oxygenated, i.e. it operates using oxygen present in the surrounding air. An example of this type is produced by BRUEST INDUSTRIES INC. The advantage of this type of heater is that the catalysed gas reaction which produces the infra-red radiation proceeds at a relatively low temperature, compared with catalysts requiring forced oxygenation, and the reaction is flameless.
It is preferred to provide a flow of dry air around the glazed article to remove water vapour produced during drying. It is important to ensure that the catalytic heater is ventilated both to replenish the oxygen in the surrounding air and to remove the reaction products. Normally the article to which glaze has been applied would be placed relatively close to the heater (a distance of, perhaps, 0.5m or less) and so a circulation of air in the vicinity of the heater and glazed article may serve both purposes.
More than one catalytic infra-red heater may be used, for example to provide radiation from more than one direction or over a large area.
The infra-red radiation may be used alone to effect drying of a glaze but it may be preferred to provide another source of heat in addition to the infra-red radiation. For example, warm or hot air may be used to further enhance the drying of glazed articles which may be particularly advantageous for drying glaze on certain articles which have surfaces which are more difficult for the infra-red radiation to reach such as cups or vases for example.
Preferably the article upon which glaze is to be dried is moved relative to the infra-red heater to optimise the absorption of radiation over the entire surface to be dried. For example the glazed article may be rotated relative to the heater.
A preferred form of apparatus for putting the method into effect comprises a chamber, at least one catalytic infra-red heater located within said chamber, support means upon which an article which has been coated with a glaze which is to be dried may be supported such that it is exposed to radiation from said heater(s) and means for providing a flow of dry air through said chamber. Preferably the support means are rotatable. The support means are preferably mounted upon a conveyor, which may be indexed, so that a number of articles carrying a coating of glaze to be dried may be moved in turn into a position in which they are exposed to radiation from the heater(s) so that the glaze may be dried.
In one, particularly preferred form, the apparatus comprises a conveyor upon which support means are mounted and which is arranged to convey an article to be glazed sufficiently close to a series of catalytic infra-red heaters so that a coating of glaze upon said article may be exposed to radiation emitted from each heater. Preferably the apparatus comprises glaze application means located in the path of the conveyor before each catalytic heater. Using such apparatus, which is especially suitable in the mass production of glazed clay articles, a coating of glaze may be applied, e.g. by spraying, before the article is conveyed past each catalytic heater and so the entire process of building up a glaze finish from several coats of glaze may be automated. Preferably such apparatus also includes loading, unloading and cooling zones through which the conveyor passes.
Apparatus suitable for putting the method of drying a glaze into effect will now be described, by way of example only and with reference to the accompanying drawings, which are:
Fig.l, a cross-section through a
glaze drying apparatus and
Fig.2, a schematic plan of a two
stage glazing line.
The apparatus comprises an elongate chamber 10 made of stainless steel with part 11 of the walls of the enclosure being made of perforated stainless steel sheet. Four catalytic infra-red heaters 12 are supported within the chamber and connected to a supply of gas and also a source of electricity to supply pre-heating elements in each heater to bring it up to a working temperature of about 15OOC , The number of heaters 12 supplied and their location and positioning depend on the type of product being dried or cured. A conveyor 13 extends along and through the chamber. Supports 14 are mounted spaced apart from each other on the conveyor and each is driven to rotate about a vertical axis relative to the conveyor. Glaze-coated pottery articles 15 are conveyed through the chamber 10 each supported upon a support 14 to be rotated whilst being exposed to long-wave infra-red radiation from the heaters 12.
Hot dry air is introduced into the chamber through the perforated walls 11 via ducts 16, 17. The air, which would normally have become hot and wet is extracted from the top of the chamber by an extractor fan 18. Some of the air is recirculated via dryers 19 back into the chamber. The air flows in the ducting are controlled by dampers 20. In a pottery factory the hot air may be heated by waste heat from kilns or ovens employed in a different manufacturing process or by heat exchanger. The flow of air through the chamber assists drying of the glaze by removing the products of drying or curing from the vicinity of the articles 15 and also provides oxygen for the catalytic heaters 12.
The arrangement of infra-red heaters and the flow of air may be different for different shapes of article on which glaze is to be dried. For example, deep articles, such as cups or vases may require hot air to be directed into the article to assist drying in those parts of the article which are least accessible to the infra-red radiation and, possibly, furthest from the heaters.
A schematic plan of a two-stage glazing line is shown in Fig.2. Each glaze drying or curing stage 23, 25 comprises an apparatus as shown in Fig.l. In the scheme shown, unglazed pottery or clay-ware articles are loaded onto a conveyor at stage 21. It is then conveyed to a first glazing stage 22 where a coating of glaze is applied to each article in turn, e.g. by spraying or dipping. The articles then pass through a first glaze drying or curing stage 23 where the coating applied at 22 is dried using catalytic infra-red heaters for example as shown in Fig.l. A further coating of glaze is applied at 24 and that second coating dried at 25 in a similar apparatus to that used at 23. The articles are then conveyed to a final curing stage 26 before being cooled down at stage 27 and unloaded at 28. Of course further coating and drying steps may be added after stage 25 if a thicker glaze is required.
Whilst the reduction in glaze-drying times achieved by using the method and apparatus of the invention are especially significant for drying water-based glaze coatings, they can also be used to cure traditional lead-based glazes.
Claims (14)
1. A method of drying a coating of glaze applied to an article, the method comprising exposing said coating to longwave infra-red radiation supplied by a catalytic infra-red heater.
2. A method according to Claim 1, further comprising providing a flow of dry air around the glazed article to remove water vapour produced during drying.
3. A method according to Claim 1 or 2, wherein more than one catalytic infra-red heater is used.
4. A method according to any one of the preceding claims, further comprising the step of providing another source of heat in addition to the infra-red radiation.
5. A method according to Claim 4, wherein said other source of heat comprises warm or hot air.
6. A method according to any one of the preceding claims, wherein the article upon which glaze is to be dried is moved relative to the infra-red heater to optimise the absorption of radiation over the entire surface to be dried.
7. A method according to Claim 6, wherein the glazed article is rotated relative to the heater.
8. A method of drying a coating of glaze applied to an article, the method substantially as hereinbefore described with reference to the accompanying drawings.
9. An apparatus for use in a method according to any one of the preceding claims, the apparatus comprising a chamber, at least one catalytic infra-red heater located within said chamber, support means upon which an article which has been coated with the glaze which is to be dried may be supported such that it is exposed to radiation from the or each said heater, and means for providing a flow of dry air through said chamber.
10. An apparatus according to Claim 9, wherein the support means is rotatable.
11. An apparatus according to Claim 9 or 10, wherein the support means are mounted upon a conveyor.
12. An apparatus according to any one of Claims 9 to 11, further comprising a conveyor upon which support means is mounted and which is arranged to convey an article to be glazed sufficiently close to a series of catalytic infra-red heaters so that a coating of glaze upon said article may be exposed to radiation emitted from each heater.
13. An apparatus according to Claim 12, further comprising glaze application means located in the path of the conveyor before each catalytic heater.
14. An apparatus according to Claim 12 or 13, further comprising loading, unloading and cooling zones through which the conveyor passes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9622674A GB2318858A (en) | 1996-10-31 | 1996-10-31 | A method of drying glaze in a UCV drying apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9622674A GB2318858A (en) | 1996-10-31 | 1996-10-31 | A method of drying glaze in a UCV drying apparatus |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB9622674D0 GB9622674D0 (en) | 1997-01-08 |
| GB2318858A true GB2318858A (en) | 1998-05-06 |
Family
ID=10802219
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9622674A Withdrawn GB2318858A (en) | 1996-10-31 | 1996-10-31 | A method of drying glaze in a UCV drying apparatus |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2318858A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113028787A (en) * | 2021-03-12 | 2021-06-25 | 广西职业技术学院 | Red pottery high efficiency energy saving drying device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2292106A (en) * | 1994-08-11 | 1996-02-14 | Donald Richard Mcgee | Method of releasing a moulded clay product from a mould |
-
1996
- 1996-10-31 GB GB9622674A patent/GB2318858A/en not_active Withdrawn
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2292106A (en) * | 1994-08-11 | 1996-02-14 | Donald Richard Mcgee | Method of releasing a moulded clay product from a mould |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113028787A (en) * | 2021-03-12 | 2021-06-25 | 广西职业技术学院 | Red pottery high efficiency energy saving drying device |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9622674D0 (en) | 1997-01-08 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |