A SYSTEM AND METHOD FOR CLEANING A BOILER

Abstract

The invention relates to a system (1) connectable to a boiler, the system comprising housing (2) connectable to the boiler defining a shock wave chamber (3). An electrically conducting wire (4) is provided in the shock wave chamber, and electrical means (5) are provided for generating an electrical discharge pulse through the wire such that to evaporate the wire. Thereby a shock wave for is generated for cleaning of dust deposit from surfaces in the boiler. Further to this, a method for cleaning a boiler is disclosed.

Claims

1. A system (1) connectable to a boiler, the system comprising a housing (2) connectable to the boiler defining a shock wave chamber (3), an electrically conducting wire (4) provided in the shock wave chamber, and electrical means (5) for generating an electrical discharge pulse through the wire such that to evaporate the wire and generate a shock wave for cleaning of dust deposit from surfaces in the boiler.

2. The system according to claim 1 wherein the system comprises or is connectable to a pipe (6) for guiding the shock wave into the boiler.

3. The system according to claim 1 or 2 wherein the electrical means comprises a capacitor (7) for generating the discharge pulse.

4. The system according to any one of the preceding claims comprising a wire feeding arrangement (8) configured to feed electrically conducting wire into the shock wave chamber to replace the wire after a discharge.

5. The system according to claim 4 wherein the wire feeding arrangement is connected to the electrical means (5) for generating an electrical discharge pulse through the wire.

6. The system according to claim 4 or 5 wherein the system comprises electrical contact means (9) in the shock wave chamber, and wherein the wire feeding arrangement is configured to feed wire towards the electrical contact means and to detect that the wire is in electrical contact with the electrical contact means for discharge.

7. The system according to any one of the preceding claims wherein the wire is a metal wire having dimensions in the range of 0.1-0.9 mm, preferably in the range of 0.15-0.5 mm.

8. The system according to any one of the preceding claims in the form of a movable unit for convenient transportation to and from a boiler, preferably comprising a set of wheels.

9. The system according to any one of the preceding claims further comprising a purge-air system configured to provide a controllable atmosphere in the housing, preferably comprising a pumping means for pumping air into the housing.

10. A method for cleaning a boiler comprising the steps of connecting a system according to any one of claims 1 to 9 to the boiler, providing an electrical current through the electrically conducting wire, to discharge the wire in order to generate a shock wave, guiding the shock wave into the boiler for cleaning of dust deposit from surfaces in the boiler.

11. The method according to claim 10 comprising feeding electrically conducting wire into the shock wave chamber for discharge.

12. The method according to claim 11 comprising detecting that the electrically conducting wire is in electrical contact for discharge.

13. The method according to any one of claims 10 to 12 wherein the boiler is a water-tube boiler.

14. The method according to any one of claims 10 to 13 wherein the boiler is a fire-tube boiler.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0026] The invention is now described, by way of example, with reference to the accompanying drawings, in which:

[0027] FIG. 1 shows a schematic view of a system for cleaning of dust deposit from surfaces in the boiler.

[0028] FIG. 2 shows a perspective view of a system for cleaning of dust deposit from surfaces in the boiler.

[0029] FIG. 3 shows a perspective view of the system with doors removed.

[0030] FIG. 4 shows a wire feeding arrangement for the system.

DESCRIPTION OF EMBODIMENTS

[0031] In the following, a detailed description of various embodiments of the system and method under the claims are disclosed.

[0032] In FIG. 1 a schematic view of a system 1 for cleaning of dust deposit from surfaces in the boiler is shown. FIGS. 2 and 3 show two perspective views of a system 1 for cleaning of dust deposit from surfaces in the boiler, one with open doors and one with doors closed for operation. Similar features are given the corresponding reference numerals in the various figures.

[0033] The boiler may be a water-tube boiler wherein water circulates in tubes heated by hot gas from a furnace. In these types of boilers dust (soot etc.) is deposited on the outside of the tubes. Alternatively the boiler may be a fire-tube boiler wherein water circulates around tubes conducting hot gas from a furnace. In these types of boilers dust is deposited on the inside of the tubes conducting the hot gas.

[0034] The cleaning system comprises a housing 2 which is connectable to a pipe 6 leading into the boiler, by means of a pipe flange 10. The housing defines a shock wave chamber 3 formed by a T-shaped portion of the pipe. The housing is configured such that the shock wave chamber is connectable to the boiler.

[0035] Within the shock wave chamber an electrically conducting wire 4 is provided, extending from one side of the chamber to the other. The wire is of a electrically conducting metallic material and has a diameter of e.g. 0.15 mm, 0.20 mm, 0.30 mm, 0.40 mm or 0.50 mm. At one end portion, the wire is brought in contact with a first electrical contact means 9. At another portion the wire is in contact with a second electrical contact means 11, such that the wire may be subjected to an electrical current applied to a portion of the wire between the first and second electrical contact means. The first and second electrical contact means are connected to an electrical means 5 for generating an electrical discharge pulse through the wire. The electrical means comprises two capacitors 7 (250 F, 10 kV) which are connectable to the electric wire through controllable electric switching means.

[0036] The electric switching means comprises a manually controlled electrical switch 12 for the operation of the system.

[0037] The system comprises a wire feeding arrangement 8 configured to feed electrically conducting wire into the shock wave chamber to replace the wire after a discharge. The wire feeding arrangement is further shown in FIG. 4. The wire feeding arrangement comprises a roll 13 of wire and a wire drive system 14 with at least one wire drive roll. The wire feeding arrangement comprises the second electrical contact means 11 and is thereby connected to the electrical means 5 for generating an electrical discharge pulse through the wire.

[0038] The wire feeding arrangement is further configured to feed wire towards the first electrical contact means 9 arranged in the shock wave chamber. When it is detected that the wire is in electrical contact with the electrical contact means for discharge, wire feeding is interrupted. This may simply be detected as the closing of an electric circuit. Thereby the regeneration of the wire in the shock wave chamber may be automatic or semi-automatic, and the system may comprise a diagnostic function to ensure that the wire is connected for discharge.

[0039] A purge-air system comprising a pumping means 15 is configured to provide a controllable atmosphere in the housing. The pumping means is in the form of a fan for pumping air into the housing. Thereby gases generated during operation of the device may be pumped by the purge-air system and transported into the boiler. Thus the any leakage of gases to the ambient surrounding of the system, may be minimized.

[0040] The system is provided with a set of wheels 16 in order to be provided as a movable unit for convenient transportation to and from a boiler. Further to this, the housing of the system is provided with handles for easy maneuvering of the wheeled assembly.

[0041] During operation of the system, the capacitors are charged with an energy of up to 1.25*10.sup.4 J. The system is connectable to mains power 17 for charging the capacitors. The energy is released through the portion of the wire between the first and second electrical contact means. Thereby the wire is rapidly heated by the resistance in the wire material and evaporated. A plasma is created whereby the electrical current is conducted between the first and second electrical contact means through the plasma. As an effect of the evaporation and ignition of a plasma in the shock wave chamber, a shock wave is generated. The shock wave is guided through the pipe 6 connected to the boiler and into the boiler for cleaning of dust deposit from surfaces in the boiler.