A dredging device for dredging a pipe is provided including: a carrying frame, adapted to connected to a pipe; a shaking dredging unit including a first shaking plate and a second shaking plate, and the first shaking plate and the second shaking plate are arranged within the pipe; and a driving unit, connected to the carrying frame. The driving unit is connected to the first shaking plate and the second shaking plate for driving the first shaking plate and the second shaking plate to reciprocate to approach or move away from each other.

A mass-flow hopper that stores solid particulates and provides gas assistance to readily discharge the particulate matter. The mass flow hopper has an upper conical section connected via an intermediate section to a lower conical section having a lower discharge orifice. The lower conical section has a frustoconical configured gas impermeable wall lined with a gas permeable fluidizing plate spaced therefrom to define a lower space. The upper conical section slope is steeper than the lower frusto-conically configured gas permeable wall slope. Gas injected into the lower space passes from the lower space through the gas permeable fluidizing plate into the hopper to form a fluidized layer of gas between the solid particulates in the hopper and the gas permeable fluidizing plate. The fluidized layer of gas reduces wall friction within the lower conical section to facilitate discharging the particulates from the hopper.

A dredging device for dredging a pipe is provided including: a carrying frame, adapted to connected to a pipe; a shaking dredging unit including a first shaking plate and a second shaking plate, and the first shaking plate and the second shaking plate are arranged within the pipe; and a driving unit, connected to the carrying frame. The driving unit is connected to the first shaking plate and the second shaking plate for driving the first shaking plate and the second shaking plate to reciprocate to approach or move away from each other.

A doser apparatus includes a throttle device on a doser mechanism. The throttle device includes a vibratory hopper and a vibration device. The vibratory hopper is configured to hold a granular material within a vibratory hopper conduit that tapers towards a bottom opening and is configured to induce bridging of the granular material at the bottom opening. The vibration device is configured to break the bridging of the granular material at the bottom opening to induce flow of the granular material through the bottom opening to a doser reservoir of the doser mechanism, based on inducing vibration of the vibratory hopper. The throttle device is configured to control a head pressure of the granular material at a portion of a conveyor device of the doser mechanism extending into the doser reservoir based on operating the vibration device to adjustably control the flow of granular material through the bottom opening.