A dust collector, comprising: - a Venturi negative pressure generating part configured to generate negative pressure through a Venturi effect; - a dust collection part configured to collect dust through the negative pressure generated by said Venturi negative pressure generating part; - a filter part constituting a device to be flushed, said filter part being arranged between said dust collection part and said Venturi negative pressure generating part; and - a flush valve comprising: o a valve body; and o a valve spool, wherein the valve body is internally provided with a fluid passageway, and the valve body is provided with an inlet, a first outlet and a second outlet, wherein said fluid passageway fluidly connects said inlet to said first and second outlets (413 and 412), and whereby said first outlet is adapted to be fluidly connected with a device to be flushed; said valve spool comprising a movable part, a fixed part and an elastic part; wherein the fixed part is provided in the valve body; wherein the elastic part is elastically connected between the fixed part and the movable part; wherein one end of the movable part is provided with a first spool land for blocking said first outlet; said first spool land being configured to be pushed away from said first outlet by a fluid in said fluid passageway to enable flushing said device to be flushed when the pressure of said device to be flushed drops due to blockage; characterized in that the second outlet of said flush valve is fluidly connected to said Venturi negative pressure generating part, and said first outlet of the flush valve is fluidly connected with said filter part. - a Venturi negative pressure generating part configured to generate negative pressure through a Venturi effect; - a dust collection part configured to collect dust through the negative pressure generated by said Venturi negative pressure generating part; - a filter part constituting a device to be flushed, said filter part being arranged between said dust collection part and said Venturi negative pressure generating part; and - a flush valve comprising: o a valve body; and o a valve spool, wherein the valve body is internally provided with a fluid passageway, and the valve body is provided with an inlet, a first outlet and a second outlet, wherein said fluid passageway fluidly connects said inlet to said first and second outlets (413 and 412), and whereby said first outlet is adapted to be fluidly connected with a device to be flushed; said valve spool comprising a movable part, a fixed part and an elastic part; wherein the fixed part is provided in the valve body; wherein the elastic part is elastically connected between the fixed part and the movable part; wherein one end of the movable part is provided with a first spool land for blocking said first outlet; said first spool land being configured to be pushed away from said first outlet by a fluid in said fluid passageway to enable flushing said device to be flushed when the pressure of said device to be flushed drops due to blockage; characterized in that the second outlet of said flush valve is fluidly connected to said Venturi negative pressure generating part, and said first outlet of the flush valve is fluidly connected with said filter part. o a valve body; and o a valve spool, wherein the valve body is internally provided with a fluid passageway, and the valve body is provided with an inlet, a first outlet and a second outlet, wherein said fluid passageway fluidly connects said inlet to said first and second outlets (413 and 412), and whereby said first outlet is adapted to be fluidly connected with a device to be flushed; said valve spool comprising a movable part, a fixed part and an elastic part; wherein the fixed part is provided in the valve body; wherein the elastic part is elastically connected between the fixed part and the movable part; wherein one end of the movable part is provided with a first spool land for blocking said first outlet; said first spool land being configured to be pushed away from said first outlet by a fluid in said fluid passageway to enable flushing said device to be flushed when the pressure of said device to be flushed drops due to blockage; characterized in that the second outlet of said flush valve is fluidly connected to said Venturi negative pressure generating part, and said first outlet of the flush valve is fluidly connected with said filter part.