GB2372039A - Method for removing surface coatings - Google Patents
Method for removing surface coatings Download PDFInfo
- Publication number
- GB2372039A GB2372039A GB0210490A GB0210490A GB2372039A GB 2372039 A GB2372039 A GB 2372039A GB 0210490 A GB0210490 A GB 0210490A GB 0210490 A GB0210490 A GB 0210490A GB 2372039 A GB2372039 A GB 2372039A
- Authority
- GB
- United Kingdom
- Prior art keywords
- coating
- particulate solid
- spray
- fluid
- jet
- 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.)
- Granted
Links
- 238000000576 coating method Methods 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 title claims abstract description 27
- 239000011248 coating agent Substances 0.000 claims abstract description 26
- 239000007921 spray Substances 0.000 claims abstract description 25
- 239000007787 solid Substances 0.000 claims abstract description 24
- 239000000203 mixture Substances 0.000 claims abstract description 23
- 239000012530 fluid Substances 0.000 claims abstract description 16
- 239000003973 paint Substances 0.000 claims abstract description 4
- 239000002966 varnish Substances 0.000 claims abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 21
- 239000007788 liquid Substances 0.000 claims description 11
- 239000002245 particle Substances 0.000 claims description 8
- 239000010450 olivine Substances 0.000 claims description 5
- 229910052609 olivine Inorganic materials 0.000 claims description 5
- 230000003116 impacting effect Effects 0.000 claims description 3
- 238000005422 blasting Methods 0.000 abstract description 8
- 238000010438 heat treatment Methods 0.000 abstract description 5
- 238000005507 spraying Methods 0.000 abstract description 4
- 239000000463 material Substances 0.000 description 4
- 101100298222 Caenorhabditis elegans pot-1 gene Proteins 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- DNIAPMSPPWPWGF-UHFFFAOYSA-N Propylene glycol Chemical compound CC(O)CO DNIAPMSPPWPWGF-UHFFFAOYSA-N 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- ZWEHNKRNPOVVGH-UHFFFAOYSA-N 2-Butanone Chemical compound CCC(C)=O ZWEHNKRNPOVVGH-UHFFFAOYSA-N 0.000 description 2
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- 230000004075 alteration Effects 0.000 description 2
- 239000011152 fibreglass Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 239000013535 sea water Substances 0.000 description 2
- XYQHCDPZBXIAGW-UHFFFAOYSA-N Andesine Natural products COC(=O)C1=Cc2ccc3c(CCN(C)C)cc(OC)c(O)c3c2C(=O)O1 XYQHCDPZBXIAGW-UHFFFAOYSA-N 0.000 description 1
- 239000003082 abrasive agent Substances 0.000 description 1
- 230000001154 acute effect Effects 0.000 description 1
- 125000005233 alkylalcohol group Chemical group 0.000 description 1
- CNLWCVNCHLKFHK-UHFFFAOYSA-N aluminum;lithium;dioxido(oxo)silane Chemical compound [Li+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O CNLWCVNCHLKFHK-UHFFFAOYSA-N 0.000 description 1
- 229910052849 andalusite Inorganic materials 0.000 description 1
- 229910052658 andesine Inorganic materials 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- -1 congolite Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910001648 diaspore Inorganic materials 0.000 description 1
- 229910052839 forsterite Inorganic materials 0.000 description 1
- 239000013505 freshwater Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 229910001867 inorganic solvent Inorganic materials 0.000 description 1
- 239000003049 inorganic solvent Substances 0.000 description 1
- 229960004592 isopropanol Drugs 0.000 description 1
- HCWCAKKEBCNQJP-UHFFFAOYSA-N magnesium orthosilicate Chemical compound [Mg+2].[Mg+2].[O-][Si]([O-])([O-])[O-] HCWCAKKEBCNQJP-UHFFFAOYSA-N 0.000 description 1
- 239000004579 marble Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
- 238000009877 rendering Methods 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000005488 sandblasting Methods 0.000 description 1
- 239000007779 soft material Substances 0.000 description 1
- 229910052834 spessartine Inorganic materials 0.000 description 1
- 229910052642 spodumene Inorganic materials 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 description 1
- 239000008400 supply water Substances 0.000 description 1
- 238000010408 sweeping Methods 0.000 description 1
- 230000002522 swelling effect Effects 0.000 description 1
- 239000002023 wood Substances 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C1/00—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods
- B24C1/08—Methods for use of abrasive blasting for producing particular effects; Use of auxiliary equipment in connection with such methods for polishing surfaces, e.g. smoothing a surface by making use of liquid-borne abrasives
- B24C1/086—Descaling; Removing coating films
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B24—GRINDING; POLISHING
- B24C—ABRASIVE OR RELATED BLASTING WITH PARTICULATE MATERIAL
- B24C7/00—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts
- B24C7/0007—Equipment for feeding abrasive material; Controlling the flowability, constitution, or other physical characteristics of abrasive blasts the abrasive material being fed in a liquid carrier
Landscapes
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
Abstract
A method of removing a coating, such as paint, varnish, biological growth or grime, from a surface, the method comprising selecting a suitable particulate solid having a particular size of from 150-250 mm and a fluid carrier to form a spray mixture and spraying the mixture as a jet spray so as to impact and at least partially remove the coating. The hardness of the particulate solid is preferably less than 8.0 on the Moh scale. The pressure applied to the spray mixture to generate the spray is from 3x10<SP>5</SP> to 1.5x10<SP>6</SP> Nm<SP>-2</SP>. An apparatus comprising a blasting pot (1) and a compressor (2) to generate the spray mixture and propel it from a nozzle (5) is also disclosed. Heating may be applied to the carrier, either prior to or when mixing with the particulate solid.
Description
METHOD FOR REMOVING SURFACE COATINGS Field of the Invention The invention relates to removing coatings from a surface and more particularly to I'p removing paint, varnish or biological growth from the outer hull of a boat.
Background to the Invention
The application is a divisional application of UK patent application number GB 99287260.
The removal of a layer or layers from a surface by impacting an abrasive material
against the layer or layers is well known. For example, grit or sand-blasting has p t, I been used for many years to clean stone buildings, painted metal surfaces such as railings and superstructures including oil rigs. The particles of grit or sand are mobilised by means of a carrier fluid, normally air or water
The commonly used methods suffer from the drawback that damage is often caused to the material beneath those layers being removed This is especially true where the methods are employed to remove surfaces from a relatively soft material such as wood or fibre glass. In particular, where fibre glass is being cleared, damage can be caused to the gel coat layer The problem of damage caused is particularly acute where, for example, antique wooden objects are being cleaned or where the surface is part of a boat.
German patent application DE 19522001 (MINERALIEN WERKE) discloses the use of a mixture of solids, one of the solids having a higher density than the other, in order to clean and treat sensitive or polished surfaces such as brick or marble
Where water is used as the carrier fluid, then its consumption using conventional methods is often quite high Where there is a ready supply of water high consumption may not be a problem but where, due to the remoteness of a source, the water needs to be transported to the object to be cleaned, minimisation of water consumption would be advantageous
It is an object of the present invention to provide a method which alleviates the above disadvantages It is a further object of the present invention to minimise the usage of the carrier fluid when said fluid is a liquid
Summary of the Invention
In accordance with the invention there is provided a method of removing a coating such as paint o : arnish from a surface, the method comprising (i) selecting a particulate solid suitable for removing the coating from
the surface, the particulate solid having a particle size from 150 to 250 urn, (ii) selecting a fluid as a carrier for the particulate solid, (iii) distributing the particulate solid in the fluid to form a spray mixture, (iv) generating a pressurised jet of the spray mixture, (v) impacting onto a coating, the pressurised jet of spray mixture to remove the coating
Preferably, the particle size is from 170 to 190 urn
The hardness of the particulate solid is preferably less than 8. 0 on the Moh scale. It is particularly preferable for the hardness to be 6 0 to 7 0 on the Moh scale. The preferred particulate solid is olivine
In one arrangement, the method includes heating the carrier fluid
The fluid is preferably a liquid It is particularly preferable that the liquid used is water
The temperature of the liquid is preferably maintained below 50C It is particularly preferable that the liquid is heated to a temperature between 25 and 40C
The solid to liquid ratio in the jet spray is preferably approximately 2 to I volume for volume
The jet advantageously is directed to impact the coating at an angle of
approximately 45 .
, In use, the jet is moved-preferably in a circular motion-back and forth across the coating to be removed The pressure of the jet is advantageously from 3x105 to 1.5x106 Nm-2 and preferably from 4xI05 to lxlO6 Nm-2 Brief Description of the Drawings
The present invention will now be described more particularly with reference to the accompanying drawing which shows, by way of example only, apparatus for removing a coating from a surface in accordance with the method of the invention In the drawing
Figure I is a diagrammatical view of the apparatus C7
Description of the Preferred Embodiments Referring initially to Figure 1, an apparatus, suitable for use in the method detailed below, comprises a blasting pot I and a compressor 2 Compressed air is passed from the compressor 2, via an inlet valve 3 to the blasting pot I Water is supplied to the blasting pot via an inlet pipe 6 The blasting pot I also comprises an outlet pipe 7 The outlet pipe 7 has at its distal end a nozzle 5 Flow of material to the nozzle 5 is controlled by means of outlet valve 4
In the method according to the invention a spray mixture of olivine and water from the domestic supply, at ambient temperature, is charged to the blasting pot I Compressed air at a pressure of approximately 7J Nm-2 from the compressor 2 is then passed through the inlet valve 3 and pressurises the blasting pot I up to approximately 1210 Nm-2 When a suitable pressure has been reached in the pot 1, the pressure can be released when required by opening the outlet valve 4 which is attached to the nozzle 5 The nozzle 5 is approximately 15 cm long with an outlet diameter of approximately 1 9 cm The excess pressure forces the spray mixture of olivine and water out of the pot 1 and through the nozzle 5 at a pressure, often called the blast pressure, of approximately 6105 Nm-2 When the spray mixture is ejected through nozzle 5 and directed against the surface coating as described hereinbelow, it acts to abrade the coating and remove it whilst leaving the surface beneath the coating relatively undamaged and ready to be treated or for a new coating to be applied Where necessary, a constant water feed may be introduced via the inlet pipe 6
The nozzle 5 can either be directed by hand or remotely When directed by hand, the nozzle is held such as to deliver the abrading spray mixture at an angle to the coated surface The angle is usually approximately 45 The distance the nozzle is held from the surface will vary according to the conditions under which spraying is being carried out, the mixture being sprayed
and the coating being removed. A distance of approximately 50 cm has been found to give good results for a variety of coatings Although a coating can be removed by simply passing the nozzle across the surface in a single sweeping action, a number of passes could be carried out, each
subtending the same angle to the surface, or subtending a different angle C, 9 z In addition, a circular motion may also be imparted to the jet spray to improve coating removal. The circular motion can be imparted manually, by the action of a jet spray or by mechanical means For example, the action of the spray leaving the nozzle is used to induce motion in the nozzle, by giving the direction of the spray a radial component relative to the longitudinal axis of the nozzle
Alternatively, a small motor is used to move the nozzle in a circular motion.
For ease of operation, the outlet valve 4 is conveniently situated adjacent to the nozzle but can be remote from it. The nozzle can have different forms to deliver particular jet sprays where required The width of the outlet of the nozzle should be wide enough to prevent clogging, and narrow enough to allow concentration of the force delivered by the spray onto a small enough area to be effective For hand-held nozzles the outlet is typically 1 V4 to 2 1/2 cm in diameter
The inlet air pressure admitted through value 3 is typically 6x105 to 10x105 Nm-2.
Although compressed air supplied by an on-site compressor will usually be most convenient, air or other gases supplied in pressurised cylinders can also be used, for example, where no power source for a compressor is available The pressure built up inside the pot 1, prior to spraying is typically less than 20x10 Nom-2 and is
normally less than 14xl05 Nm-2 The blast pressure can be up to 12x10 Nm', but can be as low as 4x105 Nm-2. The pressure used will depend very much on the coating being removed, and on the nature of the surface which is coated.
During use, the initial pressure built up in the pot will drop back from its initial value, perhaps down to approximately 3x105 Nm-2 The composition of the jet spray delivered can be varied by alteration of the rate of water addition to the pot, but can also be varied by changing the operating
pressures The composition can thus be adjusted to suit the nature of the coating material being removed, and the surface which it coats A typical composition will be between approximately I I and 3 1 of particulate solid to liquid
As alternatives or in addition to olivine (also known as forsterite)-which depending on its composition has a Moh hardness of between 6 5 to 7-other minerals such as andalusite, spodumene, diaspore, congolite, spessartine and andesine may also be used In addition, man-made materials in the form of a particulate solid of the requisite hardness range may also be used
The particulate solid can have a particle size of 60 to 100 mesh It has been found that if the particles are too large, then they can cause damage to the surface itself,
rather than simply removing the coating A mixture of particles having differing mesh sizes could also be used
The water used can, in addition to coming from the domestic supply, also be fresh water or sea water If sea water is used then the surface should preferably be rinsed off with domestic supply water, prior to its being re-coated As alternatives to or in addition to water, certain organic or inorganic solvents may also be employed Examples of solvents which can be employed are alkyl alcohols, such as ethanol, propanol, iso-propanol, ethylene glycol or propylene glycol Other solvents which may be contemplated include acetone, butanone and sulpholane
Especially suitable are those which may have a solublising or swelling effect on the surface coating being removed, thus rendering it more easily removable
When necessary, suitable measures will need to be taken to protect the operator and the environment from these solvents
In addition to liquids as described above, other fluids may be employed, either partially or fully in their place Suitable examples of fluids which may be used
include air or nitrogen Z7 The water supplied from a domestic or external source is normally provided at a temperature of below 20C Where necessary however it may be heated up to about 50C Heating the water to a temperature of between 25 to 40C has been found to
reduce water consumption The heating may be accomplished by means of an z
independent heating element mounted within the blasting pot or alternatively to the water inlet supply. As an alternative, where a petrol or diesel powered generator is used to operate for example a compressor to produce compressed air, then the exhaust pipe can pass through the water, on its way to the gases being vented, and the heat from the exhaust can be utilised to raise the temperature of the water
The apparatus used can conveniently be bolted to a trailer or other suitable transporting vehicle to enable it to be taken more easily to where it is required.
This will also allow for example, a supply of water for spraying to be taken, where it would otherwise be difficult to obtain
It will of course be understood that the invention is not limited to the specific details described herein, which are given by way of example only, and that various modifications and alterations are possible with the scope of the appended claims
Claims (6)
- CLAIMS A method of removing a coating, such as paint, varnish, biological growth or grime, from a surface, the method comprising (i) selecting a particulate solid suitable for removing the coating from the surface, the particulate solid having a particle size from 150 to250 urn, (ii) selecting a fluid as a carrier for the particulate solid, (iii) distributing the particulate solid in the fluid to form a spray mixture, (iv) generating a pressurised jet of the spray mixture, the pressure of5
- 2 the jet being from 30 to 1 5 JO" m'\ (v) impacting onto a coating the pressurised jet of spray mixture to remove the coating 2 A method according to claim !, wherein the particulate solid has a particle size of from 170 to 190 m
- 3 A method according to either claim i or claim 2, wherein the hardness of the particulate solid is less than 8 0 on the Moh scale
- 4 A method according to claim 3, wherein the hardness of the particulate solid is from 6 0 to 7 0 on the Moh scale
- 5 A method according to any preceding claim, wherein the particulate solid is olivine
- 6. A method according to any preceding claim, wherein the temperature of the fluid is maintained below 50C 7 A method according to claim 6 wherein the temperature of the fluid is heated to a temperature of from 25 to 40C 8 A method according to any preceding claim, wherein the fluid is a liquid 9 A method according to claim 8, wherein the liquid is water 10 A method according to either of claims 8 or 9, wherein the solid to liquid volumetric ratio in the spray mixture is approximately 21.I I A method according to any preceding claim, wherein the mixture is directed so as to impact the coating at an angle of approximately 45 12 A method according to any preceding claim, wherein the jet spray is moved, in use, in a circular motion back and forth across the coating 13 A method according to any preceding claim, wherein the pressure is from4x105 JOtolJONm'.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB9826683.6A GB9826683D0 (en) | 1998-12-04 | 1998-12-04 | Compositions for removing surface coatings |
| GBGB9827214.9A GB9827214D0 (en) | 1998-12-11 | 1998-12-11 | Methods and compositions for removing surface coatings |
| GB9928726A GB2344348B (en) | 1998-12-04 | 1999-12-06 | Method for removing surface coatings |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0210490D0 GB0210490D0 (en) | 2002-06-12 |
| GB2372039A true GB2372039A (en) | 2002-08-14 |
| GB2372039B GB2372039B (en) | 2002-10-30 |
Family
ID=27269572
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0210490A Expired - Lifetime GB2372039B (en) | 1998-12-04 | 1999-12-06 | Method for removing surface coatings |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2372039B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8353741B2 (en) | 2009-09-02 | 2013-01-15 | All Coatings Elimination System Corporation | System and method for removing a coating from a substrate |
| US11780051B2 (en) | 2019-12-31 | 2023-10-10 | Cold Jet, Llc | Method and apparatus for enhanced blast stream |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3446541A1 (en) * | 1984-12-20 | 1986-06-26 | Horst 4600 Dortmund Bertulies | Process and device for cleaning masonry, in particular for cleaning hot coke ovens |
-
1999
- 1999-12-06 GB GB0210490A patent/GB2372039B/en not_active Expired - Lifetime
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3446541A1 (en) * | 1984-12-20 | 1986-06-26 | Horst 4600 Dortmund Bertulies | Process and device for cleaning masonry, in particular for cleaning hot coke ovens |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8353741B2 (en) | 2009-09-02 | 2013-01-15 | All Coatings Elimination System Corporation | System and method for removing a coating from a substrate |
| US8500520B2 (en) | 2009-09-02 | 2013-08-06 | All Coatings Elimination System Corporation | System and method for removing a coating from a substrate |
| US11780051B2 (en) | 2019-12-31 | 2023-10-10 | Cold Jet, Llc | Method and apparatus for enhanced blast stream |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2372039B (en) | 2002-10-30 |
| GB0210490D0 (en) | 2002-06-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 732E | Amendments to the register in respect of changes of name or changes affecting rights (sect. 32/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20071206 |
|
| S28 | Restoration of ceased patents (sect. 28/pat. act 1977) |
Free format text: RESTORATION ALLOWED Effective date: 20110301 |