Method for replacing a swirler

1. A method for replacing a swirler of a premixing or main burner of a burner arrangement, wherein the swirler is connected to a distributor flange plate of the burner arrangement via a fuel gas feed pipe and a fuel oil feed line accommodated in the fuel gas feed pipe, the method comprising:

a) separating the swirler by a first severing of both the fuel gas feed pipe and the fuel oil feed line close to the swirler;

b) removing the separated swirler;

c) separating an end portion of the remaining fuel gas feed pipe by a second severing of the remaining fuel gas feed pipe, without also severing the fuel oil feed line;

d) removing the separated end portion of the fuel gas feed pipe;

e) providing a sleeve which is configured to replace the end portion of the fuel gas feed pipe that was separated in step c), and the sleeve is configured to be pushed at least partially onto or into the remaining fuel gas feed pipe;

f) arranging the sleeve respectively on or in the remaining fuel gas feed pipe;

g) providing a second swirler, from which a second fuel gas feed pipe end portion and a second fuel oil feed line end portion protrude axially;

h) integrally connecting a remaining un-severed part of the fuel oil feed line to the second fuel oil feed line end portion protruding from the second swirler;

i) arranging the sleeve between a remaining un-severed part of the fuel gas feed pipe and the second fuel gas feed pipe end portion protruding from the second swirler; and

j) integrally connecting the sleeve to a remaining un-severed part of the fuel gas feed pipe on the one hand and to the second fuel gas feed pipe end portion protruding axially from the second swirler on the other hand.

2. The method as claimed in claim 1 , wherein the end portion of the remaining fuel gas feed pipe separated in step c) and the sleeve which replaces the end portion of the remaining fuel gas feed pipe have the same length.

3. The method as claimed in claim 1 , wherein the end portion of the remaining fuel gas feed pipe separated in step c) and the sleeve which replaces the end portion of the remaining fuel gas feed pipe have a conical form.

4. The method as claimed in claim 1 , further comprising welding to produce the integral connections in steps h) and j).

5. The method as claimed in claim 4 , further comprising, before the weld seams are produced in steps h) and j), subjecting those weld seams to weld seam preparation.

6. The method as claimed in claim 1 , wherein the second fuel oil feed line end portion is configured to protrude from the second swirler further than the fuel oil feed line end portion protrudes from the separated swirler.

7. The method as claimed in claim 1 , wherein the separating of the swirler is along a first parting plane and the separating of the end portion is along a second parting plane.