System comprising a discharge electrode assembly and an electrostatic precipitator unit comprising such a system
The invention relates to a system comprising a discharge electrode assembly, the system being for an electrostatic precipitator unit. The discharge electrode assembly comprises a discharge electrode to be electrically connected to an associated high voltage generator via an insulator. The connection is established via a connector pin and an insulator connector. The parts comprise a number of mutually engageable locking surfaces designed to prevent mutual translational and rotational movement of the parts. The invention also relates to an electrostatic precipitator unit comprising such a system. The discharge electrode assembly is designed so that it is easier to assemble and arrange correctly in a flow passage of a flue gas passageway than what is known from prior art. In particular, it is designed to provide a lower risk of misalignment of the discharge electrode with respect to the flue gas passage than what is known from prior art.
1 . A system for an electrostatic precipitator unit configured for insertion in a flue gas passageway, comprising:
a flue gas inlet configured to receive a flow of flue gas,
a flue gas outlet configured to vent the flow of flue gas,
a pipe forming a flow passage extending between the flue gas inlet and the flue gas outlet, and
a discharge electrode assembly,
wherein the discharge electrode assembly comprises:
a discharge electrode arranged in the flow passage and configured to be electrically connected to an associated high voltage generator, which provides an electric field in a region around the discharge electrode during use,
an insulator arranged between the associated high voltage generator and the discharge electrode during use, the insulator having a longitudinal axis fixedly arranged parallel to a central axis of the pipe forming the flow passage,
a connector pin connected to the discharge electrode at a first end, and
an insulator connector connecting the insulator and a second end of the connector pin,
wherein:
the connector pin comprises a first locking surface at the first end and a second locking surface at the second end,
the discharge electrode comprises a third locking surface at an upper end,
the insulator connector comprises a fourth locking surface, and a fifth locking surface, and
the insulator comprises a sixth locking surface,
wherein:
the first and the third locking surfaces are configured to form a fixed mutual engagement preventing translational and rotational movement of the discharge electrode in relation to the connector pin,
the second and the fourth locking surfaces are configured to form a fixed mutual engagement preventing translational and rotational movement of the connector pin in relation to the insulator connector, and
the fifth and the sixth locking surfaces are configured to form a fixed mutual engagement preventing translational and rotational movement of the insulator connector in relation to the insulator,
so that when all the locking surfaces are in their respective mutual engagements, a longitudinal axis of the discharge electrode is aligned with the central axis of the pipe.
2 . The system according to claim 1 , wherein:
the mutual engagement between the first and the third locking surfaces is releasable, and/or
the mutual engagement between the second and the fourth locking surfaces is releasable.
3 . The system according to claim 1 , wherein:
the first locking surface is a protrusion extending from the first end of the connector pin, and
the third locking surface is a locking hole matching the shape and dimensions of the protrusion.
4 . The system according to claim 1 , wherein:
the second locking surface is a recess in the connector pin, and
the fourth locking surface is a combination of:
a guiding hole in the insulator connector configured to receive the second end of the connector pin, and
a set screw configured to fixedly engage with the recess when the connector pin is at a predefined position in the guiding hole.
5 . The system according claim 4 , wherein:
the insulator connector comprises the guiding hole, and
the connector pin is configured to slide along the guiding hole in the insulator connector to allow for movement of the discharge electrode relative to the insulator.
6 . The system according to claim 1 , wherein the discharge electrode comprises a first discharge electrode part and a second discharge electrode part, wherein the first and second discharge electrode parts are aligned and releasably and fixedly connected to each other during use of the discharge electrode.
7 . An electrostatic precipitator unit for insertion in a flue gas passageway, comprising:
a system according to claim 1 ,
a high voltage generator connected to the discharge electrode configured to provide an electric field in a region around the discharge electrode, when the high voltage generator is turned on, and
a controller for controlling the operation of the high voltage generator and the discharge electrode.
8 . The electrostatic precipitator unit according to claim 7 , further comprising a casing extending laterally from the pipe, the casing comprising:
a first compartment adjacent to the pipe, and
a second compartment at a distance from the pipe and separated from the first compartment by a heat shield plate along at least a part of a height of the first compartment,
wherein the controller and the high voltage generator are arranged:
in the second compartment, or
in a third compartment adjacent to and at least partly separated from the second compartment by a mounting plate supporting the high voltage generator and the controller, and
wherein walls of the casing are provided with:
at least one lower hole at a lower region of the second compartment, and
at least one upper hole at an upper region of the second compartment,
the at least one lower hole being configured to allow air to be drawn into the second compartment from the surroundings and the at least one upper hole being configured to allow air to be vented out of the second compartment thereby causing a flow of air along the second compartment as a result of thermal convection caused by hot flue gas flowing in the flow passage during use of the electrostatic precipitator unit.
9 . The electrostatic precipitator unit according to claim 8 , wherein the heat shield plate is bent or curved so that a horizontal distance between the heat shield plate and both the controller and the high voltage generator is larger adjacent to the walls of the casing than midway between the walls of the casing.
10 . The electrostatic precipitator unit according to claim 7 , wherein both the at least one lower hole and the at least one upper hole are provided in two opposing walls of the casing.
11 . The electrostatic precipitator unit according to claim 7 , wherein the insulator is arranged in a fourth compartment of the casing, the fourth compartment being above and at least partly separated from the second or third compartment in which the controller and the high voltage generator are arranged.
12 . The electrostatic precipitator unit according to claim 7 , wherein the controller and the high voltage generator are arranged in a control box forming a unitary enclosure.
13 . The electrostatic precipitator unit according to claim 7 , further comprising a brush stop arranged at the flue gas outlet and extending across the flow passage, the brush stop being configured to prevent a sweeping brush from passing the brush stop when the electrostatic precipitator unit is inserted in the flue gas passageway.