GB2539466A

GB2539466A - Centrifugal separator

Info

Publication number: GB2539466A
Application number: GB1510627.1A
Authority: GB
Inventors: William Fell Anthony; Rouse Angus; Madden Alfred; Nash Robin; Marques Tiago
Original assignee: Mann and Hummel GmbH
Current assignee: Mann and Hummel GmbH
Priority date: 2015-06-17
Filing date: 2015-06-17
Publication date: 2016-12-21
Anticipated expiration: 2035-06-17
Also published as: GB2539466B; CN106256440A; DE102016006277A1; GB201510627D0; CN106256440B

Abstract

A centrifugal separator 10 has a base 14, a substantially vertical spindle 16 which is upstanding from the base 12, two or more rotor assemblies 18A, 18B mounted one above the other in series on the spindle 16, a housing 12 comprising a cover 34 enclosing the rotor assemblies 18A, 18B, and a liquid supply duct for supplying the rotor assemblies 18A, 18B with liquid to be cleaned. This arrangement reduces the required head space, i.e. the free space above the separator 10, necessary to remove each of the rotor assemblies 18A, 18B to clean or otherwise service the separator 10 and is particularly applicable to removing contaminant particles from a lubricating oil circuit of an internal combustion engine.

Description

Centrifugal separator

TECHNICAL FIELD

The invention relates to a centrifugal separator.

BACKGROUND

Centrifugal separators, sometimes referred to as centrifuges, are well known for removing contaminant particles from a lubricating oil circuit of internal combustion engines. They are also known for separating particulate matter from liquids or to separating liquids of different densities in a variety of industrial processes. Typically, the principle of operation of a centrifuge is that a housing contains a rotor which is supported therein to spin about a substantially vertical axis, i.e. a spindle. Liquid is supplied to pass through the rotor (as the rotor spins about the axis) such that denser contaminant materials or particles are separated from the liquid centrifugally and are retained within the centrifuge.

As contaminants accumulate within a centrifuge, it is essential that it is routinely cleaned out in order to maintain effectiveness of operation. Cleaning requires that the rotor is removed from the housing by lifting the rotor above the top of the spindle.

Therefore, the size of the rotor determines a required head space, i.e. free space above the centrifuge necessary to clean or otherwise service the centrifuge. While it is often desirable to increase the capacity of a centrifuge by increasing the size of the rotor, larger rotor sizes typically require a larger head space. Consequently, where the available head space is limited, for example by the design of an engine of which the centrifuge is component part, the size of the centrifuge, and thus its capacity, may be undesirably restricted. It is an object of invention to address this problem.

SUMMARY OF THE INVENTION

According to an aspect of the invention, there is provided a centrifugal separator comprising a base, a substantially vertical spindle upstanding from the base, two or more rotor assemblies mounted one above the other in series on the spindle, a housing comprising a removable cover enclosing the rotor assemblies, and a liquid supply dud for supplying the rotor assemblies with liquid to be cleaned. This arrangement reduces the required head space, i.e. the free space above the separator, necessary to allow removal of each of the rotor assemblies to clean or otherwise service the separator.

In certain embodiments, the substantially vertical spindle may be a split spindle formed from two or more connectable spindle elements. A split spindle may help further reduce the required head space.

The centrifugal separator may advantageously include at least one fluid shield mounted between adjacent rotor assemblies. During operation of the separator, such a shield minimises the volume of liquid falling onto and flowing over the one or more rotor assemblies mounted lower in the series. The or each fluid shield may be an umbrellalike structure in that it suitably has a convex upper surface. In certain embodiments, the one or more fluid shields may be mounted on the vertical spindle. In alterative embodiments, the one or more fluid shields may be mounted on the housing.

The spindle may have an axial bore and one or more outlets therefrom positioned so as to correspond to each of the two or more rotor assemblies so that liquid is supplied to each of the two or more rotor assemblies via the axial bore and these outlets.

In certain embodiments the base may have an inlet duct which communicates with the axial bore of the spindle. An outlet port for discharging liquid from the separator may be provided as a passage through the base.

In preferred embodiments, the two or more rotor assemblies are substantially the same size and shape as each other. This allows cost-effective production of such a stacked arrangement of rotor assemblies.

The housing preferably includes an upstanding annular wall in addition to the removable cover. In this respect, the height of the removable cover also affects the headspace requirement, so in conjunction with having two or more rotor assemblies mounted one above the other, the removable cover should beneficially also be less than the height of the housing which encloses those assemblies. The upstanding annular wall may be formed as an integral part of the base.

In certain embodiments, the removable cover may have a height substantially equal to or less than the height of one of at least one of the two or more rotor assemblies.

The separator will typically be a self-powered separator in which case the two or more rotor assemblies are each provided with one or more drive nozzles configured for emitting liquid from the rotor assemblies so as to cause rotation of the rotor assemblies by virtue of a reactive force. However, the invention could also be applicable to centrifugal separators with separate drive means.

According to a further aspect of the invention, there is provided a method for separating solid contaminants from a liquid comprising: providing a centrifugal separator comprising a base, a substantially vertical spindle upstanding from the base, two or more rotor assemblies mounted one above the other in series on the spindle, a housing comprising a removable cover enclosing the rotor assemblies, and a liquid supply dud for supplying the rotor assemblies with liquid to be cleaned; supplying the rotor to assemblies with the liquid to be cleaned; and rotating the rotor assemblies so that the solid contaminates are separated from the liquid by centrifugal force. This method utilises an apparatus requiring a reduced the head space, i.e. the free space above the separator, necessary to clean or otherwise service the separator, as noted above.

The method may be used for removing contaminants from a lubricating oil circuit of an internal combustion engine. In that case, the rotor assemblies will typically be self-powered by flow of the lubricating oil through the separator. The method could also be used to separate abrasive contaminants from liquid used in an industrial process, for example from honing oil, grinding machine coolant, electrode discharge machining zo fluid, or oil quench fluid from furnaces, and in water purification processes. In that case, the rotor assemblies may have separate drive means.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described further, by way of example only, with reference to the accompanying figure, which is a cross-sectional side view of an embodiment of a centrifugal separator according to the invention.

DETAILED DESCRIPTION

As illustrated, an exemplary embodiment of a self-powered centrifugal separator 10 according to the invention has a housing 12, a base 14 and a substantially vertical spindle 16 upstanding from the base 14. The base 14 locates and supports a lower end of the spindle 16. Upper and lower rotor assemblies 18A, 18B are mounted in series upon the spindle 16, such that the rotor assemblies 18A, 18B are mounted one above the other. Further, the two rotor assemblies 18A, 18B are mounted on the spindle 16 such that each assembly 18A, 18B can rotate about the vertical axis of the spindle 16.

A fluid shield 20 is mounted between the upper and lower rotor assemblies 18A, 18B. The fluid shield 20 is a circular umbrella-like structure having a convex upper surface and spans above the lower rotor assembly 18B. The diameter of the fluid shield 20 is at least equal to or greater than that of the lower rotor assembly 18B.

An axial bore 22 extends through the length of the spindle 16 as a liquid supply duct for supplying the rotor assemblies 18A, 18B with liquid, i.e. working fluid to be cleaned/filtered. In the illustrated embodiment, the axial bore 22 communicates with upper and lower through bores 24A, 24B. The through bores 24A, 24B are formed through the spindle 16 at right angles to the axial bore 22 so as to provide outlets therefrom. The upper and lower rotor assemblies 18A, 18B are mounted at positions overlying the upper and lower through bores 24A, 24B, respectively. Owing to this arrangement, the through bores 24A, 24B communicate with an interior of each of the rotor assemblies 18A, 18B such that working fluid supplied to the rotor assemblies 18A, 18B enters the assemblies 18A, 18B via the through bores 24A, 24B. In the illustrated embodiment, the rotor assemblies 18A, 18B are provided with dividers 26A, 26B which separate the interior of each rotor assembly 18A, 18B to form respective outer chambers 28A, 28B and inner chambers 30A, 30B. As illustrated, the dividers 26A, 26B may be tubular structures each having a radially extending skirt at their lower end. In operation, working fluid enters each of the rotary assemblies 18A, 18B and flows through an upper opening in each of the respective dividers 26A, 26B, from the inner zo chambers 30A, 30B, into the outer chambers 28A, 28B, and then back via a lower opening in each of the dividers 26A, 26B from the outer chambers 28A, 28B into the inner chambers 30A, 30B.

The rotor assemblies 18A, 18B further include respective outlet nozzles 32A, 32B, which in the illustrated embodiment communicate with the respective inner chambers 30A, 30B. The outlet nozzles 32A, 32B are each provided at a radial distance from the vertical axis of the spindle 16 and are configured such that working fluid exits the rotor assemblies 18A, 18B via the outlet nozzles 32A, 32B in a direction generally tangential to the rotor assemblies 18A, 18B.

In the illustrated embodiment, the housing 12 includes an upstanding annular wall 36 formed as part of the base 14 and a removable cover 34. An uppermost edge of the annual wall 36 is approximately level with the top of lower rotor assembly 18B. The cover 24 is mounted over the upper rotor assembly 18A and is secured to the base 14 about the upper edge of the annual wall 36 by any suitable means, for example a clamp, such as a ring clamp. The housing 12, namely the upstanding wall 36 and the cover 34 together, encloses the rotor assemblies 18A, 18B. The provision of the annular wall 36 means that the height of the removable cover 34 is less than the overall height of the housing 12 (the height of the housing 12 being equal to the height of the wall 36 and the cover 34 combined). The cover 34 may have a height substantially equal to or less than the height of the upper rotor assembly 18A. As illustrated, the cover 34 locates and support an upper end of the spindle 16 by a fitment 38.

An inlet duct 40 extends through the base 14 to enable supply of working fluid from an inlet port 42 to the axial bore of the spindle 16. Working fluid flows from the inlet port 42 to the through bores 24A, 24B via the inlet duct 40 and the axial bore 22. Arrows provided in accompanying figure indicate a preferred path of fluid flow within the to separator 10.

The separator 10 is typically used to clean oil. Working fluid, such as oil containing a contaminant, is supplied to the separator 10 under elevated pressure via the inlet port 42. Working fluid flows to the through bores 24A, 24B, as described above, where a portion of the working fluid passes into the interior of the upper rotor assembly 18A and a further portion of the fluid passes into the interior of lower rotor assembly 18B. The fluid flows through each of the rotor assemblies 18A, 18B and exits therefrom via the outlet nozzles 32A, 32B, as described above. The tangential emission of fluid from the rotor assemblies 18A, 18B, via the nozzles 32A, 32B, causes rotation of the rotor assemblies 18A, 18B thereby generating a centrifugal force which separates the contaminant from the working fluid in the outer chambers 28A, 28B. Separated contaminant accumulates within the outer chambers 28A, 28B, primarily as a cake adhering to an interior surface of each of the rotor assemblies 18A, 18B or a liner provided therein. Fluid exiting the rotor assemblies 18A, 18B drains to the base 14 and exits the separator 10 via an outlet port 44.

Working fluid exiting the upper rotor assembly 18A is deflected by the fluid shield 20 so that it does not flow directly over the lower rotor assembly 18B. Specifically, fluid is directed radially outwardly by the fluid shield 20 to flow down an inner surface of the annular wall 36. The fluid shield 20 prevents working fluid exiting the upper rotor assembly 18A from adversely affecting the speed or balance of the lower rotor assembly 18B.

As contaminant within rotor assemblies 18A, 18B accumulates, the separator 10 must be periodically cleaned/emptied. To clean the separator 10, a service operative removes the cover 34, including the fitment 38, and lifts the upper rotor assembly 18A off the spindle 16, followed by the fluid shield 20, followed by the lower rotor assembly 18B. The rotor assemblies 18A, 18B are then cleaned out before they are remounted, along with intervening fluid shield 20, onto the spindle 16. The head space, i.e. the free space above the separator 10, necessary to clean or otherwise service the centrifuge 10, need only be large enough to accommodate lifting off any one of the cover 34 or the rotor assemblies 18A, 18B as the operative disassembles or reassembles the separator 10. Consequently, the arrangement of the separator 10, specifically having the two rotor assemblies 18A, 18B mounted to the spindle in series, provides overall a large capacity separator having a relatively small head space requirement. The head space requirement necessary for servicing the separator 10 can be less than that required for servicing a separator with equal capacity but only a single rotor.

The invention is not restricted to the details of any foregoing embodiments and many variations in design detail are possible within the scope of the appended claims. It will be understood that while the illustrated embodiment comprises two rotor assemblies, any number of multiple rotor assemblies may be provided on top of one another in series in alternative embodiments. Therefore, alternative embodiments should preferably also include more than one fluid shield to avoid fluid impacting the performance of rotors mounted lower in the separator.

The spindle may not be formed as a single elongate element as illustrated in the accompanying figure. In certain embodiments, the spindle may be formed as a split spindle comprising two or more elongate pieces connectable at their respective ends so as to form the spindle. A split spindle may help further reduce the head space requirement in arrangements where the spindle is also removed during servicing of the separator.

In alternative embodiments, the fluid shield may have a modified shape, such as a frusto-conical shape. Further, the fluid shield may not be mounted to the axial spindle and may be alternatively mounted to the housing. In certain embodiments, the fluid shield may be clamped between the housing and the removable cover.

Further, the invention is not limited to self-powered centrifugal separators, such as that which is described above. In altemative embodiments, a centrifugal separator having two or more rotor assemblies mounted in series upon a spindle may be provided where rotation of the rotor assemblies is by other drive means, for example an electric motor.

In the illustrated embodiment, the rotor assemblies are identical to each other. In other embodiments, the rotor assemblies may be only approximately similar to each other. While this may be preferable, for reasons of manufacturing components and to permit modular design/assembly of a multi-rotor centrifugal separator, it is not essential. In other embodiments, the rotor assemblies may differ in size and/or shape.

The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims and drawings). Each feature disclosed in this specification (including any accompanying claims and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Claims

CLAIMS1. A centrifugal separator comprising a base, a substantially vertical spindle upstanding from the base, two or more rotor assemblies mounted one above the other in series on the spindle, a housing comprising a removable cover enclosing the rotor assemblies, and a liquid supply duct for supplying the rotor assemblies with liquid to be cleaned.
2. A centrifugal separator according to claim 1, wherein the substantially vertical spindle is a split spindle formed from two or more connectable spindle elements.
3. A centrifugal separator according to claim 1 or 2, further comprising at least one fluid shield mounted between adjacent rotor assemblies.
4. A centrifugal separator according to claim 3, wherein the at least one fluid shield has a convex upper surface.
5. A centrifugal separator according to any preceding claim, wherein the spindle has an axial bore and one or more outlets therefrom positioned so as to correspond to each of the two or more rotor assemblies, and liquid is supplied to each of the two or more rotor assemblies via the axial bore and the outlets.
6. A centrifugal separator according to any preceding claim, wherein the base has an inlet duct which communicates with the axial bore of the spindle, and liquid is supplied to each of the two or more rotor assemblies via the inlet duct.
7. A centrifugal separator according to any preceding claim, further comprising an outlet port for discharging liquid from the separator, the outlet port provided as a passage through the base.
8. A centrifugal separator according to any preceding claim, wherein the two or more rotor assemblies are substantially the same size and shape as each other.
9. A centrifugal separator according to any preceding claim, wherein the housing includes an upstanding annular wall and the cover is connected to the wall.
1 0. A centrifugal separator according to claim 9, wherein the upstanding annular wall is formed as an integral part of the base.
11. A centrifugal separator according to any preceding claim, wherein the base is configured to locate and/or support a lower end of the spindle.
12. A centrifugal separator according to any preceding claim, wherein the cover is configured to locate and/or support an upper end of the spindle.
13. A centrifugal separator according to any preceding claim, wherein the cover has a height substantially equal to or less than the height of the upper one of the two or more rotor assemblies.
14. A centrifugal separator according to any preceding claim, wherein the separator is a self-powered separator in that the two or more rotor assemblies are each provided with one or more drive nozzles configured for emitting liquid from the rotor assemblies so as to cause rotation of the rotor assemblies by virtue of a reactive force.
15. A method for separating solid contaminants from a liquid comprising: providing a centrifugal separator comprising a base, a substantially vertical spindle upstanding from the base, two or more rotor assemblies mounted one above the other in series on the spindle, a housing comprising a removable cover enclosing the rotor assemblies, and a liquid supply duct for supplying the rotor assemblies with liquid to be cleaned; supplying the rotor assemblies with the liquid to be cleaned; and rotating the rotor assemblies so that the solid contaminates are separated from the liquid by centrifugal force.
16. A method according to claim 15, wherein the spindle has an axial bore and one or more outlets therefrom corresponding to each of the two or more rotor assemblies, and liquid to be cleaned is supplied to the two or more rotor assemblies from via the axial bore and the outlets.
17. A self-powered centrifugal separator substantially as hereinbefore described with reference to and as illustrated in the accompanying drawing.