Apparatus for backwashing filter
AssigneeMitsubishi Heavy Industries, Ltd.
InventorsYoshinori Koyama, Osamu Shinada, Yuichiro Kitagawa, Takao Hashimoto
Life of this patent
Estimating the term…
Abstract
The reliability of backwashing valves constituted of first backwashing valves and second backwashing valves is ensured. A first backwashing valve (backwashing-gas rear valve) (7) that controls gas for backwashing and a second backwashing valve (backwashing-gas front valve) (6) that operates at slower speed than the first backwashing valve (7) are disposed, in a series including two or more thereof, at backwashing-gas introducing pipes individually provided for each of the filter blocks.
Claims2
A method for backwashing filter in a dust removal device using porous material, the dust removal device having a plurality of filter blocks which are constituted by a plurality of filter elements accommodated in a pressure vessel and partitioning plates that partition or support these filter blocks, the pressure vessel being internally divided into a space for dust-containing gas, which includes a dust hopper, and a plurality of spaces for purified gas;
- the method comprising:
- periodically performing backwashing of the filter elements for each of the filter blocks, whereby a backwashing nozzle is directed toward the filter elements, the backwashing nozzle provided inside purified-gas lead-out pipes or inside spaces upstream thereof, each of which is connected to the plurality of spaces for the purified gas or a filter-element outlet, and
- controlling gas for backwashing with a first backwashing valve, and a second backwashing valve that operates at a slower speed than the first backwashing valve, the first backwashing valve and the second backwashing valve disposed, in a series including two or more thereof, at backwashing-gas introducing pipes individually provided for each of the filter blocks;
- wherein the second backwashing valve is moved slowly from a fully-closed position to a fully-open position in 2 to 10 seconds upon starting a backwashing cycle, with the first backwashing valve in a fully closed position;
- and
- wherein the first backwashing valve is rapidly moved from the fully-closed position to a fully-open position in 0.1 to 1 second once the second backwashing valve reaches the fully-open position so as to perform backwashing for 0.1 to 1 second.
A method for backwashing filter in a dust removal device using porous material, the dust removal device having a plurality of filter blocks which are constituted by a plurality of filter elements accommodated in a pressure vessel and partitioning plates that partition or support these filter blocks, the pressure vessel being internally divided into a space for dust-containing gas, which includes a dust hopper, and a plurality of spaced for purified gas;
- the method comprising:
- periodically performing backwashing of the filter elements for each of the filter blocks, whereby a backwashing nozzle is directed toward the filter elements, the backwashing nozzle provided inside purified-gas lead-out pipes or inside spaces upstream thereof, each of which is connected to the plurality of spaces for the purified gas or a filter-element outlet, and
- controlling gas for backwashing by a first backwashing valve alone, wherein the first backwashing valve and a second backwashing valve are disposed, in a series including two or more thereof, at the backwashing-gas introducing pipes individually provided for each of the filter blocks;
- and
- wherein the first backwashing valve is moved rapidly from a fully-closed position to a fully-open position in 0.1 to 1 second upon starting a backwashing cycle, with the second backwashing valve in a fully-open position, so as to perform backwashing for 0.1 to 1 second.
Dependencies are inferred from the claim text.