Centrifuge

Abstract

The centrifuge has a two-part rotor provided with two sets of outlets. One set ejects fluid in the form of jets so as to drive the centrifuge. The second set ejects fluid which has been cleaned. Outlets are also provided for the contaminants removed from the cleaned fluid. The liquid flow rate for the drive is high while the flow rate for centrifuging can be low or medium. The liquid flows can be delivered from different sources.

Description

This invention relates to a centrifuge. More particularly, this invention relates to a centrifuge for cleaning a fluid, such as cooling water employed in the operation of an internal combustion engine.

Briefly, the invention provides a centrifuge which has a hollow rotor forming a separating chamber with an inlet for liquid to be cleaned and an outlet for cleaned liquid. In addition, the rotor has another liquid outlet which is arranged to produce a jet so that the reaction of the jet is used to impart a rotary force on the rotor.

Generally, the drive function for a cleaning centrifuge requires a high rate of flow whereas optimum centrifuge action for cleaning requires a low to medium rate of flow. However, by having two separate outlets in the rotor, one of which at least primarily serves to produce the drive jet and the other of which at least primarily serves as an outlet for the cleaned liquid, it is possible to design these outlets to serve their own functions without the compromise which would be necessary if a single outlet served both functions.

The rotor may comprise two separate chambers, namely the separating chamber and a drive chamber with the second liquid outlet leading out of the drive chamber. With a construction of this kind, the flow of liquid for cleaning and for driving can be kept apart from one another. The drive chamber and the separating chamber are connected to input ducts in the rotor which are independent of one another. In such cases, the liquids fed to the centrifuge may be taken from different sources. This may be of advantage in certain cases, as will be apparent from the following description.

The outlet for the cleaned liquid is also arranged to produce a jet, the reaction of which imparts a rotary force on the rotor. Thus, the emerging cleaned liquid assists the liquid emerging from the other liquid outlet in driving the rotor. Further, these outlets can lead into a common discharge chamber. This greatly simplifies the centrifuge, since there is no need for separate discharge conduits for the liquids emerging from the different outlets.

These and other objects and advantages of the invention will become more apparent from the following detailed description and appended claims taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates an axial section through a centrifuge according to the invention; and

FIG. 2 diagrammatically illustrates the centrifuge of FIG. 1 incorporated in a system for cleaning the cooling water of a large Diesel engine.

Referring to FIG. 1, the centrifuge 10 includes a base 11 to which a cover 12 is secured in a suitable manner. The base 11 supports a stationary spindle 13 in a fixed manner while a two-part rotor 14 is mounted on the spindle 13 by means of bearing bushes 15, 16, 17, 35 for rotation about a vertical axis. The parts of the rotor 14 are secured together in sealed relation as shown. The rotor 14 contains a partition 18 which separates the interior of the rotor 14 into a drive chamber 20 and a separating chamber 21. The drive chamber 20 is connected by a passage 22 formed in the spindle 13 and in a central part of the rotor 14 to an input duct 23 for an operating medium used for the drive, e.g. in this case, cooling water. The separating chamber 21 is connected by a duct 24 in the spindle 13 and rotor 14 to a second input duct 25 for an operating medium which is to be cleaned. As shown, the duct 24 in the rotor 14 is formed by means of a shaped member which sealingly engages the partition 18 at one end and is sealed, such as by an O-ring, relative to the rotor 14. As will be apparent from FIG. 1, the bottom part of the spindle 13 contains a hollow tube 26 which is sealed off from the spindle 13 and which separates the ducts 22 and 24 from one another in this zone. As is also apparent from FIG. 1, the drive chamber 20 is provided with outlets in the form of tangential drive nozzles 27 for expelling drive jets of water while the separating chamber 21 is provided with outlets 28 in the top zone of the rotor 14. In order to simplify the drawing the outlets 28 are shown as being disposed radially but preferably the outlets 28 extend tangentially in the same way as the drive nozzles 27. In the construction of the centrifuge illustrated, the nozzles 27 and the outlets 28 lead into a common discharge chamber 30 formed within the cover 12 and base 11. This chamber 30 connects with a tank (not shown) so that the cleaned cooling water can flow out.

As shown, that part of the discharge chamber 30 which is situated above the ducts 23 and 25, is connected to the part situated therebeneath via apertures (not shown). The ducts 23 and 25 may, for example, be formed in a diametral tubular part 31, semi-circular apertures being provided between the part 21 and the part of the base 11 having the form of a body of revolution.

During operation, the input duct 23 can be connected to the delivery pipe of a pump which delivers the operating medium, in this case cooling water, which is used for the drive. The flow per unit of time of cooling water fed to the drive chamber 20 through the duct 23 and emerging through the nozzles 27 can be so selected that the rotor 14 of the centrifuge 10 rotates at the required speed.

The operating medium to be cleaned, again cooling water, is taken through the input duct 25 and through the duct 24 into the separating chamber 21 and after cleaning passes out to the discharge chamber 30 via the outlets 28. In order to prevent the exit flow from disturbing the centrifuge movement, the cover 12 is provided with a baffle plate 32, which ensures that the cleaned water flows down along the inner wall of the cover 12. As shown, the baffle plate 32 is positioned below the outlets 28 so as to be disposed under the exit flow.

The matter which is removed from the cooling water, for example, lubricating oil or liquid fuel, which is lighter than water, is fed through a duct 33 to an exit duct 34 in the spindle 13 and is discharged therefrom. As shown, the duct 33 is sealed from the duct 24 and a baffle is arranged to maintain the matter to be removed near the duct 33. Heavier particles contained in the cooling water are deposited on the interior surface of the wall of the rotor 14 and can be removed therefrom from time to time.

The flow to the separating chamber 21 per unit of time can be adjusted substantially independently of the drive requirements. For example, it has been found that the cleaning of the operating medium is better with small flows per unit of time.

Referring to FIG. 2, the centrifuge 10 is incorporated in a cleaning system for the cooling water of a large Diesel engine E, for example for marine propulsion. The cleaning system comprises two tanks 40, 41 which are interconnected by a pipe 42 near the bottom of the tanks 40, 41 with one tank 41 receiving polluted cooling water from the engine E via a pipe 43. The two tanks 40 and 41 have a common venting pipe 44. Cooling water to be fed to the engine E is drawn from the tank 40 by a cooling water pump 45 and fed to a cooling water pipe 46. A branch pipe 47 leads from the cooling water pipe 46 to the centrifuge 10 which is situated above the tank 41. The pipe 47 is connected to the input duct 23 (FIG. 1) which leads into the drive chamber. The pipe 47 contains a valve 48 by means of which the system can be switched on and off.

A pipe 50 branches from the pipe 47 and contains an ejector 51. The intake aperture of the ejector 51 is connected by a suction line 52 including a hose 52' to a float 53 bearing an intake cup 54 which is connected to the suction line 52 and the top edge of which is a small distance above the level of water in the tank 41. Since the pollutant to be separated in this case is mainly oil, this ensures that the top layer containing most of the oil is drawn from the tank 41.

The pipe 50 is connected to the intake pipe 25 of the centrifuge 10 (FIG. 1) which leads into the separating chamber 21. As will be apparent from FIG. 2, the pipe 50 is provided with a spill valve 55 by means of which the pressure in the line 52 is controlled.

The water used for the drive together with the purified water flows back into the tank 41 from the discharge chamber 30 through a pipe 56. The separated oil is discharged from the discharge duct 34 (FIG. 1) through a pipe 57 to a reservoir 58.

During operation, the polluted cooling water is fed to the tank 41 through the pipe 43. A top layer having a high oil concentration forms in the tank 41 and is shown by cross-hatching in the drawing. The cooling water to be cleaned is drawn from this layer through the suction line 52 by means of the float 53 so that full use is made of the available centrifuge action. The clean cooling water in the bottom of the tank 41 can flow through the pipe 42 into the clean water tank 40. The water is drawn from the tank 40 by the cooling pump 45 for cooling the engine E while some of this water is also used to drive the centrifuge 10 and to draw in the polluted cooling water by the ejector 51 as is known. Since clean water from the tank 40 is used to drive the centrifuge, the two output flows passing through the nozzles 27 and the outlets 28 can be combined since the cooling water in both cases is clean. This greatly simplifies the centrifuge and the entire cleaning system.

Of course, the centrifuge described by way of example can be modified in various ways. In particular the rotor need not have two completely separate chambers 20 and 21. The operating medium to be cleaned can be introduced into the rotor through a common pipe, whereupon part of the medium passes out through the drive nozzles and part of the flow is centrifuged and taken out through the other outlets.

Claims

What is claimed is:

1. The combination of a centrifuge having a hollow rotor including a separating chamber having an inlet for liquid to be cleaned and a first outlet for expelling cleaned liquid outwardly of said rotor, and a drive chamber having a second outlet for expelling a jet of liquid outwardly of said rotor to impart a rotary force on said rotor; a tank connected to said first outlet to receive cleaned liquid therefrom; and a pump having a suction line connected to said tank and a delivery line connected to said drive chamber to deliver cleaned liquid from said tank to said drive chamber.

2. The combination as set forth in claim 1 which further includes a branch line connected to said delivery line and to said separating chamber, and an ejector in said branch line for drawing liquid to be cleaned from said tank into said branch line.

3. The combination as set forth in claim 1 which further includes a float in said tank having an inlet connected to said ejector to draw liquid from adjacent the surface of liquid in said tank.

4. The combination as set forth in claim 1 wherein said tank and said pump connected to an internal combustion engine with said centrifuge being connected to clean a cooling liquid of said engine.

5. The combination as set forth in claim 1 which further includes a second tank connected to said first tank to receive clean liquid therefrom and to said suction line of said pump to deliver clean liquid thereto, and a reservoir connected to said centrifuge to receive separated oil therefrom.