Soot blower lance

Claim 2

In a lance for a boiler soot blower, said lance comprising: an outer casing including flow nozzles mounted about a head end thereof and a liner mounted therein, said outer casing including closure means about said head end, said liner including closure means at an end thereof proximate to the head end of said outer casing, said liner defining a central flow section within said lance, said liner and said outer casing cooperating to define an annular flow section within said lance, and cleaning medium supply means extending into said central flow section for introducing a cleaning medium to said lance, the improvement comprising: means formed in said liner for placing said central flow section in fluid communication with said annular flow section to maintain the velocity of said cleaning medium through said annular flow section substantially constant; and means for enabling said cleaning medium to pass through said flow nozzles.

Claim 3

The soot blower lance as claimed in claim 1 wherein said annular flow section varies in cross-sectional area along the length thereof.

Claim 4

The soot blower lance as claimed in claim 2 wherein said variation in cross-sectional area of said annular flow section is defined by variations of the wall thickness of said outer casing, and said means for maintaining said velocity constant are positioned in relation to said variation in said wall thickness.

Claim 5

The soot blower lance as claimed in claim 2 wherein said variations in the cross-sectional area of said annular flow section are defined by steps formed on the internal surface of said outer casing, and said means for maintaining said velocity constant are positioned substantially adjacent said steps.

Claim 6

The improvement as claimed in claim 1 wherein said means for maintaining said velocity constant comprise orifices formed in said liner.

Claim 7

The improvement as claimed in claim 5 wherein said orifices are sized such as to develop vena contracta in cleaning medium flowing therethrough.

Claim 8

In a lance for a boiler soot blower, said lance comprising: an outer casing including flow nozzles mounted about a head end thereof and a liner mounted therein, said outer casing including closure means about said head end, said liner including closure means at an end thereof proximate to the head end of said outer casing, said liner defining a central flow section within said lance, said liner and said outer casing cooperating to define an annular flow section within said lance, and cleaning medium supply means extending into said central flow section for introducing a cleaning medium to said lance, the improvement comprising: means formed in said liner for placing said central flow section in fluid communication with said annular flow section to minimize the build-up of a pressure differential between said cleaning medium in said central flow section and said cleaning medium in said annular flow section; aNd means for enabling said cleaning medium to pass through said flow nozzles.

Claim 9

In a lance for a boiler soot blower, said lance comprising: an outer casing including flow nozzles mounted about a head end thereof and a liner mounted therein, said outer casing including closure means about said head end, said liner including closure means at an end thereof proximate to the head end of said outer casing, said liner defining a central flow section within said lance, said liner and said outer casing cooperating to define an annular flow section within said lance, and cleaning medium supply means extending into said central flow section for introducing a cleaning medium to said lance, the improvement comprising: means formed in said liner for placing said central flow section in fluid communication with said annular flow section to minimize the build-up of a pressure differential between said cleaning medium in said central flow section and said cleaning medium in said annular flow section; aNd means for enabling said cleaning medium to pass through said flow nozzles.

Claim 10

The improvement as claimed in claim 7 wherein said means for precluding the build-up of a pressure differential are also for maintaining the velocity of said cleaning medium through said annular flow section substantially constant.

Claim 11

The improvement as claimed in claim 7 wherein said means for precluding the build-up of a pressure differential are orifices formed in said liner.

Claim 12

The improvement as claimed in claim 8 wherein said means for precluding the build-up of a pressure differential comprise a plurality of spaced orifices.

Claim 13

A lance for retractable soot blower comprising: a cylindrical outer casing, said cylindrical outer casing having a head end and a tail end, said cylindrical outer casing becoming progressively thinner from said tail end to said head end, said cylindrical outer casing being enclosed about said head end and provided with flow nozzle means proximate thereto; a cylindrical liner mounted cylindrically within said cylindrical outer casing, said cylindrical liner defining a central flow section within said lance and being enclosed about an end proximate to the head end of said casing; said cylindrical liner and said cylindrical outer casing cooperating to define an annular flow section within said lance, said annular flow section increasing in cross-sectional area from said tail end to said head end of said cylindrical outer casing; cleaning medium supply means extending coaxially within said liner, said supply means for introducing a cleaning medium to said lance; means for positioning said cylindrical liner coaxially within said cylindrical outer casing; means for positioning said cleaning medium supply line within said liner; means formed in said cylindrical liner for communicating said central flow section with said annular flow section; and means for enabling said cleaning means to pass through said flow nozzles.

Claim 14

A lance for retractable soot blower comprising: a cylindrical outer casing, said cylindrical outer casing having a head end and a tail end, said cylindrical outer casing becoming progressively thinner from said tail end to said head end, said cylindrical outer casing being enclosed about said head end and provided with flow nozzle means proximate thereto; a cylindrical liner mounted cylindrically within said cylindrical outer casing, said cylindrical liner defining a central flow section within said lance and being enclosed about an end proximate to the head end of said casing; said cylindrical liner and said cylindrical outer casing cooperating to define an annular flow section within said lance, said annular flow section increasing in cross-sectional area from said tail end to said head end of said cylindrical outer casing; cleaning medium supply means extending coaxially within said liner, said supply means for introducing a cleaning medium to said lance; means for positioning said cylindrical liner coaxially within said cylindrical outer casing; means for positioning said cleaning medium supply line within said liner; means formed in said cylindrical liner for communicating said central flow section with said annular flow section; and means for enabling said cleaning means to pass through said flow nozzles.

Claim 15

The lance as claimed in claim 11 wherein said means for communicating said central flow section and said annular flow section comprises orifices formed in said liner.

Claim 16

The lance as claimed in claim 12 wherein said orifices are disposed along said liner in relation to the variation in the cross-sectional area of said annular flow section.