The present invention relates to an oil filtration unit (1) for removal of solid contaminants from contaminated oil, the oil filtration unit (1) comprising a housing (2) which comprises a housing inlet (3) adapted to receive contaminated oil from the surroundings and to release the contaminated oil to an inner opening (4) of the housing (2) at a first pressure (p1) and a housing outlet (12) adapted to release filtered oil to the surroundings, and an oil filter (6) for filtering the contaminated oil, the oil filter (6) being arranged in the inner opening (4) of the housing (2) and comprising a filter inlet defined by an outer surface (7) of the oil filter (6), an inner filter volume (8) adapted to receive filtered oil at a second pressure (p2), where the second pressure (p2) is lower than the first pressure (p1), and a filter outlet inside the housing (2) providing fluid/liquid communication between the inner filter volume (8) and the housing outlet (12) in order to release the filtered oil from the inner filter volume (8), where the filter outlet comprises a hydraulic resistance providing a fluid/liquid flow restriction between the inner filter volume (8) and the housing outlet (12) in order to increase the second pressure (p2) inside the inner filter volume (8) and to release the filtered oil from the inner filter volume (8) to the housing outlet (12) at a third pressure (p3), where the third pressure (p3) is lower than the second pressure (p2).

The present invention provides a multi plate screw press sludge dewatering machine and a helical shaft thereof. The multi plate screw press sludge dewatering machine includes fixed rings, movable rings, the helical shaft, a sludge inlet tank and a sludge discharging tank; the helical shaft adopts a variable diameter variable pitch helical shaft, a lead angle arrangement sequence of a helical blade of the whole helical shaft is gradual reduction from the sludge discharging tank to the sludge inlet tank, and the lead angle arrangement sequence is gradually reduced from 16-22 to 6-14; a pitch of the helical shaft is gradually increased along a direction from the sludge inlet tank to the sludge discharging tank; a diameter of a shaft body of the helical shaft is gradually increased along with a direction of the sludge discharging tank from a position of a shaft length; and blockage prevention plates are arranged on two sides of the bottom of the helical blade. The helical shaft in the present invention is specially designed, so that the pitch is more reasonable, a helical angle is gentler, frictional resistance when sludge passes through the helical shaft may be effectively reduced, and phenomena of shaft blockage and shaft sticking of the sludge may be reduced.

The present invention provides a multi plate screw press sludge dewatering machine and a helical shaft thereof. The multi plate screw press sludge dewatering machine includes fixed rings, movable rings, the helical shaft, a sludge inlet tank and a sludge discharging tank; the helical shaft adopts a variable diameter variable pitch helical shaft, a lead angle arrangement sequence of a helical blade of the whole helical shaft is gradual reduction from the sludge discharging tank to the sludge inlet tank, and the lead angle arrangement sequence is gradually reduced from 16-22 to 6-14; a pitch of the helical shaft is gradually increased along a direction from the sludge inlet tank to the sludge discharging tank; a diameter of a shaft body of the helical shaft is gradually increased along with a direction of the sludge discharging tank from a position of a shaft length; and blockage prevention plates are arranged on two sides of the bottom of the helical blade. The helical shaft in the present invention is specially designed, so that the pitch is more reasonable, a helical angle is gentler, frictional resistance when sludge passes through the helical shaft may be effectively reduced, and phenomena of shaft blockage and shaft sticking of the sludge may be reduced.

Described is a stacked-plate apparatus having a plurality of plates stacked along an axis and having gaps between adjacent plates, each of which act as flow passageways for flow of fluid from a fluid inlet to a fluid outlet. Pairs of adjacent plates comprise one and optionally two lips, which extend axially into the flow passageway at the fluid inlet, thereby narrowing an inlet gap between the plates at the fluid inlet. The lips enhance the flow of fluid towards the fluid outlet of the flow passageway, for at least a working distance downstream thereof, as compared to a pair of adjacent plates that does not have the lips.

Described is a stacked-plate apparatus having a plurality of plates stacked along an axis and having gaps between adjacent plates, each of which act as flow passageways for flow of fluid from a fluid inlet to a fluid outlet. Pairs of adjacent plates comprise one and optionally two lips, which extend axially into the flow passageway at the fluid inlet, thereby narrowing an inlet gap between the plates at the fluid inlet. The lips enhance the flow of fluid towards the fluid outlet of the flow passageway, for at least a working distance downstream thereof, as compared to a pair of adjacent plates that does not have the lips.

A filter may include: a first member having a first surface provided with a channel; and a second member set with a second surface thereof covering the channel. The first member may include a first passable portion that allows a fluid to pass between the first surface and a first space, which is defined beside a surface of the first member opposite to the first surface, through a first area of the channel. The second member may include a second passable portion that allows the fluid to pass between the second surface and a second space, which is defined beside a surface of the second member opposite to the second surface, through a second area of the channel distanced from the first area.

A filter may include: a first member having a first surface provided with a channel; and a second member set with a second surface thereof covering the channel. The first member may include a first passable portion that allows a fluid to pass between the first surface and a first space, which is defined beside a surface of the first member opposite to the first surface, through a first area of the channel. The second member may include a second passable portion that allows the fluid to pass between the second surface and a second space, which is defined beside a surface of the second member opposite to the second surface, through a second area of the channel distanced from the first area.

A screen intake system has a body with an open end and a chamber. A flat screen is disposed at the open end of the body. To keep the screen clear of debris, an airburst system has pipes disposed in the chamber. The pipes dispose parallel to one another adjacent the flat screen, and each of the pipes has orifices in a side facing the flat screen. Directors are disposed along the backs of the pipes in a lattice, and each of the directors has a channel in which the pipe disposes. Compressed air released by valves from a tank dispersed from the pipe's orifices. Each of the directors directs the resulting water/airburst from the orifices toward the adjacent flat screen to clear it of debris.

A screen intake system has a body with an open end and a chamber. A flat screen is disposed at the open end of the body. To keep the screen clear of debris, an airburst system has pipes disposed in the chamber. The pipes dispose parallel to one another adjacent the flat screen, and each of the pipes has orifices in a side facing the flat screen. Directors are disposed along the backs of the pipes in a lattice, and each of the directors has a channel in which the pipe disposes. Compressed air released by valves from a tank dispersed from the pipe's orifices. Each of the directors directs the resulting water/airburst from the orifices toward the adjacent flat screen to clear it of debris.

The present invention relates to a ballast water treatment system. The ballast water treatment system comprises: a filter and electrolysis unit for receiving ballast water from the outside, and filtering and electrolyzing the ballast water; a first sensor unit for measuring seawater characteristics of the ballast water passing through the filter and electrolysis unit; a control unit for determining a contamination level of the ballast water according to the measured seawater characteristic values so as to generate control signals for determining the strength of electrolysis and the input amount of chlorine dioxide; a chlorine dioxide generation unit for generating the chlorine dioxide; a UV/TiO.sub.2 system which includes a TiO.sub.2-coated plate, generates an OH radical through an interaction between ultraviolet rays and TiO.sub.2 so as to enable the OH radical to sterilize residual microorganisms included in the ballast water passing through the filter and electrolysis unit; an automatic neutralization treatment device which includes a neutralizing agent, receives a neutralizing agent discharge signal from the control unit, and neutralizes the ballast water passing through the filter and the electrolysis unit; and a second sensor unit for measuring a TRO concentration of the ballast water neutralized in the automatic neutralization treatment device and transferring the measurement result to the control unit, wherein the control unit generates a control signal for controlling an amount of the neutralizing agent discharged from the automatic neutralization treatment device according to the measurement result received from the second sensor unit. Thus, the sterilization efficiency for the ballast water satisfies the USCG standards during the ballasting step for the ballast water.