Galvanizing furnace

Abstract

A galvanizing furnace (1) with a galvanizing vat (6) and a furnace housing (2) surrounding the galvanizing vat (6), which furnace housing has a rectangular cross-section. The furnace housing (2) has two opposite longitudinal sidewalls (4) and two opposite end walls (5) and further comprises burners for heating molten zinc in the galvanizing vat (6). In the areas of two diagonally opposite corners of the furnace housing (2), at least one first receptacle (15) is provided for a burner. In the areas of the other two diagonally opposite corners of the furnace housing (2), a second receptacle (16) is provided for a burner. The burners are arranged optionally either in the first receptacles (15) or in the second receptacles (16). Flames produced by the burners are conducted in the area between a longitudinal sidewall (4) of the furnace housing (2) and the opposite wall of the galvanizing vat (6).

Claims

1. A method for operating a galvanizing furnace (1); said furnace comprising: a galvanizing vat (6) and a furnace housing (2) surrounding the galvanizing vat (6), which furnace housing has a rectangular cross-section, wherein the furnace housing (2) has two opposite longitudinal sidewalls (4) and two opposite end walls (5), and with a burner for heating molten zinc in the galvanizing vat (6), characterized in that in areas of two diagonally opposite corners of the furnace housing (2) in each case one first receptacle (15) for the burner is provided, in areas of other two diagonally opposite corners of the furnace housing (2) in each case a second receptacle (16) for the burner is provided, and that the burner is arranged in a choice of either the first receptacle (15) or, alternatively, in the second receptacle (16), wherein flames produced by the burner are conducted in an area between a longitudinal sidewall (4) of the furnace housing (2) and an opposite sidewall of the galvanizing vat (6), comprised of the following method steps: operation of the galvanizing vat during a first operating phase with the burner in the first receptacle, detection of a current wall thickness of the galvanizing vat in proximity of flame ejection of the burner, removal of the burner from the first receptacle and installation in the second receptacle when the current wall thickness goes below a specified limit value, operation of the galvanizing vat during a second operating phase with the burner in the second receptacle.

2. The method according to claim 1, characterized in that, in addition to the first receptacle and the second receptacle, a plurality of further receptacles and a plurality of further burners are provided.

3. The method according to claim 1, characterized in that an ultrasonic transducer is provided for measuring the wall thickness of the galvanizing vat (6).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the invention is explained with the aid of drawings, showing:

(2) FIG. 1: A longitudinal sectional view of an embodiment of the galvanizing furnace according to the invention.

(3) FIG. 2: A cross-sectional view of the galvanizing furnace according to FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(4) FIGS. 1 and 2 illustrate an embodiment of the galvanizing furnace 1 according to the invention. The galvanizing furnace 1 has a furnace housing 2 with a floor 3 having a rectangular contour and in each case two longitudinal sidewalls 4 and two end walls 5 protruding perpendicularly from the floor 3, wherein the two end walls 5 are arranged opposite each other and the longitudinal sidewalls 4 are arranged opposite each other. The furnace housing 2 therefore has a constant rectangular cross-section over its entire height.

(5) In the interior of the furnace housing 2, a galvanizing vat 6 is located which serves for holding molten zinc to be heated. The galvanizing vat 6 has an essentially rectangular cross-section adapted to the cross-section of the furnace housing 2, so that the sidewalls 7 of the galvanizing vat 6 are arranged at a constant distance to the longitudinal sidewalls 4 and end walls 5 of the furnace housing 2. The galvanizing vat 6 has a planar floor 8, which rests on the floor 3 of the furnace housing 2.

(6) The upper edge of the galvanizing vat 6 is accommodated in an edge segment 9 of the furnace housing 2, which edge segment extends on the top sides of the longitudinal sidewalls 4 and of the end walls 5. The open top side of the galvanizing vat 6 can be closed with a cover [not illustrated].

(7) The galvanizing vat 6 is supported with braces 10 against the inner sides of the longitudinal sidewalls 4 of the furnace housing 2. The braces 10 thus form a clamping frame for fixing the position of the galvanizing vat 6 in the furnace housing 2.

(8) One end wall 5 has a flue gas discharge orifice, which is designed in the form of a flange 11 with an exhaust gas flap 11a. The spatial pressure of the furnace atmosphere is controlled via the exhaust gas flap 11a, in order to obtain an effective temperature transition to the galvanizing vat 6.

(9) First temperature sensors 12 for measuring the temperatures in the braces 10 themselves are provided in or on the braces 10. Overheating of the braces 10 can be monitored in this way.

(10) Furthermore, second temperature sensors 13 are located in the area of the inner sides of the sidewalls 7, for measuring the temperature in the interior of the furnace housing 2.

(11) The first and second temperature sensors 12, 13 are advantageously in the form of thermocouples. Depending upon the measured values generated with the temperature sensors 12, 13, the heat output of the galvanizing furnace 1, and thus the temperature in the interior of the furnace housing 2, can be controlled.

(12) The interior of the furnace housing 2 is heated by means of burners. The burners are designed as gas burners, namely in the present case as high-speed burners 14.

(13) To support the high-speed burners 14, according to the invention first receptacles 15 are incorporated into the respective end wall 5 in two diagonally opposite corner areas of the furnace housing 2. Furthermore, second receptacles 16 are incorporated into the respective end wall 5 in the two other diagonally opposite corner areas of the furnace housing 2.

(14) The first and second receptacles 15, 16 are designed identically and are matched to the physical size of the high-speed burners 14, so that the high-speed burners 14 can optionally be installed in first or second receptacles 15, 16.

(15) FIG. 2 illustrates a receptacle 15, 16 in each corner area. In principle, multiple identical first receptacles 15 or second receptacles 16 can be arranged spaced apart above each other in each corner area, so that a high-speed burner 14 can be supported in each of these receptacles 15, 16 of a corner area.

(16) According to the invention, the high-speed burners 14 are inserted either only in the first receptacles 15 or in the second receptacles 16, in order to heat the interior of the furnace housing 2 in this way.

(17) Because the high-speed burners 14 can be installed in every corner area of the furnace housing 2, as shown in FIGS. 1 and 2, the outside walls of the galvanizing vat 6 are clad in all corner areas with flame deflector plates 17, in order to protect the walls of the galvanizing vat 6 against the flames emerging from the high-speed burners 14. The identically designed flame deflector plates 17 extend across the entire height of the galvanizing vat 6.

(18) In the configuration illustrated in FIG. 2, the high-speed burners 14 are arranged in the first receptacles 15. The second receptacles 16, in which no high-speed burners 14 exist, are tightly sealed with sealing means 18, so that the furnace walls are tightly encapsulated. The sealing means 18 can in each case be formed from furnace insulation material and a cover plate.

(19) If the galvanizing furnace 1 is operated with the burner configuration according to FIG. 2, the flames of the high-speed burner 14 are in each case conducted in the interspaces between a longitudinal sidewall 4 of the furnace housing 2 and a wall of the galvanizing vat 6, and as a result the molten zinc in the vat is heated.

(20) According to the type of installation of the high-speed burners 14 in the first receptacles 15, the flame temperature is highest in the discharge area of the high-speed burner 14 (designated A in FIG. 2) and then decreases continuously towards the area at the other end of the furnace housing 2 (designated B in FIG. 2).

(21) Accordingly, during the operation of the galvanizing furnace 1 with the burner configuration according to FIG. 2, the highest wear of the galvanizing vat 6 occurs in area A, which wear consists of a reduction of the wall thickness of the galvanizing vat 6. The reduction of the wall thickness then decreases continuously from area A to area B.

(22) During the operation of the galvanizing furnace 1, the reduction of the wall thickness due to wear is preferably recorded metrologically at regular time intervals.

(23) For this purpose, identical configurations of inspection openings 19 are incorporated into the longitudinal sidewalls 4 of the furnace housing 2, which inspection openings can be closed with covers (not illustrated separately).

(24) Ultrasonic transducers (not shown) are provided for carrying out non-contact measurement of the wall thickness of the galvanizing vat 6 during the operation of the galvanizing furnace 1. To carry out such measurement, the cover is removed from an inspection opening 19, and the ultrasonic transducer is then inserted through the inspection opening 19 to the wall of the galvanizing vat 6, where the ultrasonic transducer preferably adheres by means of an integrated magnet in a defined measuring position on the wall of the galvanizing vat 6.

(25) As can be seen from FIG. 1, four rows of inspection openings 19 are provided, with in each case three inspection openings 19 arranged one above the other. The two outer rows are arranged directly following the flame deflector plates 17. Furthermore, two central rows of inspection openings 19 are provided.

(26) By inserting ultrasonic transducers through the inspection openings 19, the wall thickness of the galvanizing vat 6 can be detected and spatially resolved, while the galvanizing furnace 1 is being operated. In particular, by inserting the ultrasonic transducers through the left-hand row of inspection openings 19, the wall thickness of the galvanizing vat 6 can be measured in area A, where the greatest wear of the galvanizing vat 6 is encountered.

(27) In particular, when it is determined in this critical area A that the wall thickness of the galvanizing vat 6 has dropped below a critical value, the mounting locations of the high-speed burners 14 are preferably exchanged during the next maintenance period of the galvanizing furnace 1 such that the high-speed burners 14 are dismantled from the first receptacles 15 and are then installed in the second receptacles 16. The first receptacles 15 are then appropriately sealed with the sealing means 18.

(28) Because in the subsequent operation of the galvanizing furnace 1 the high-speed burners 14 are now installed in the second receptacles 16, the areas B are then subjected to the greatest wear. The areas A, which were still subjected to heavy wear during the first operating phase are protected, however, since the flame temperatures of the high-speed burners 14 are now lower at those points. Therefore, in spite of the heavy wear that occurred in the galvanizing vat 6 in the areas A during the first phase, the galvanizing furnace 1 can continue to be operated without risk of damage, because in the second phase only slight wear still occurs in the areas A with the high-speed burners 14 being arranged in the second receptacles 16. The galvanizing furnace 1 can therefore continue to be operated without risk of damaging the galvanizing vat 6, until a reduction in the wall thickness in the areas B of the galvanizing vat 6 also occurs up to the limit value. In this context, the wall thickness of the galvanizing vat 6 is checked again by the measurements carried out with the ultrasonic transducers. This significantly increases the service life of the galvanizing furnace 1 with the galvanizing vat 6, compared with an operation in which the high-speed burners 14 are permanently arranged only in the first receptacles 15.

LIST OF REFERENCE NUMERALS

(29) (1) Galvanizing furnace (2) Furnace housing (3) Floor (4) Longitudinal sidewall (5) End wall (6) Galvanizing vat (7) Sidewall (8) Vat floor (9) Edge segment (10) Brace (11) Flanges (11a) Exhaust gas flap (12) First temperature sensor (13) Second temperature sensor (14) High-speed burner (15) First receptacle (16) Second receptacle (17) Flame deflector plate (18) Sealing means (19) Inspection opening