GB2539400A

GB2539400A - Fluid separator

Info

Publication number: GB2539400A
Application number: GB1510402.9A
Authority: GB
Inventors: Francis Garland Paul; Fairbairn Matthew
Original assignee: Delphi International Operations Luxembourg SARL
Current assignee: Delphi International Operations Luxembourg SARL
Priority date: 2015-06-15
Filing date: 2015-06-15
Publication date: 2016-12-21
Also published as: GB201510402D0

Abstract

A separation device (7, Fig 3) adapted to separate a fluid into at least a first and second outlet streams; said first stream being richer in particulate matter than said second outlet stream. The device comprises a container which forms a chamber 11 having a central longitudinal axis and being of generally circular cross-section. A fluid inlet means 12 is generally located towards one end of said container, and at least first and second fluid outlets 13, 14 are located towards the other end of said chamber. The fluid inlet is arranged to create a fluid cyclone/vortex within the chamber with a net general flow from the first (inlet) end to the opposite (outlets) end and the first outlet is located generally further away from the central axis compared to the second outlet. A diffuser or venturi may be located downstream of the second outlet. Preferably a fuel system including a fuel tank 2 fluidly connected to a pump (4, Fig 3) includes the separation device such as a hydro-cyclone, located downstream of the pump. The first outlet may be fluidly connected back to the tank. The separation device may be used to protect items such as pumps and injectors from debris damage.

Description

Fluid Separator

Field of the Invention

This disclosure relates to apparatus and methods of separating fluids and in particular a fluid into two separate components. It is applicable to both liquids and gases. It has particular suitability to separate out a fluid stream into two separate output streams, one of which is relatively low in particulate matter compared with the other. It has particular though not exclusive application in the filtration of contaminants in fuel systems.

Background to the Invention

Fuel cleanliness is paramount to the successful operation of all fuel injection equipment. Failure to ensure an adequate level of filtration results in deterioration of sensitive parts of the system, notably valve seats and guides in the high pressure parts of the pump and injectors. The sources or abrasive debris are (a) built-in (b) generated by wear (c) in suspension from the fuel in the tank (see figure 1). Respectively, these are traditionally minimised by (a) adequate washing and clean room assembly. (b) designing to minimise wear, and (c) providing 'paper filters as part of the system which are changed according to a maintenance schedule.

The first two of these sources of contamination may be improved by including a means of filtering fuel immediately prior to its usage in e.g. a high pressure system. However, an external 'paper' filter, which would imply additional maintenance, is an expensive solution. Some heavy duty FIE systems have a twin filter' layout where fuel is re-filtered after passing through a Transfer Pump (TP).

Hydro-cyclone devices are known in fuel systems. German Patent Application No. DE 10353367 describes a hydro-cyclone upstream of an external filter with re-circulation back to tank. German Patent Application No. DE 102004041768 describes a cyclone within an external filter and German Patent Application No. DE102004024542 describes a hydro-cyclone installed within an injector, but this device would not protect the high pressure components in the pump and rail.

However, in the prior art, as in conventional systems, fuel contaminated within the pump is not filtered. Any built-in contamination, or debris resulting from wear in the pump will not be dealt with unless it is flushed out of the pump back-leak and re-circulated through the inlet filter via the tank.

It is an object of the invention to overcome these problems.

Statement of the Invention

In one aspect is provided a filtration/separation device adapted to separate a fluid into at least a first and second outlet streams; said first stream being richer in particulate matter than said second outlet stream comprising: a container which forms a chamber having a central longitudinal axis and being of generally circular cross-section, a fluid inlet means generally located towards one end of said container, and at least first and second fluid outlets located towards the other end of said chamber, wherein said fluid inlet is arranged so as to create a fluid cyclone/vortex within said chamber with a net general flow from said first (inlet) end to said opposite (outlets) end, wherein said first outlet is located generally further away from said central axis compared to the second outlet.

The chamber is preferably conical, narrowing towards said outlet end.

The first outlet is preferably located at or adjacent to the circumference of said container. The inlet is preferably arranged to provide inlet flow which is tangential.

The second outlet is preferably located generally coincident with the central axis.

The first outlet is preferably separated from said second outlet by an edge.

The first outlet is preferably formed annular outlet port, surrounding said sccond outlet.

The first and second outlets are preferably separated by an annular edge or ridge.

The device may include a diffuser or Venturi located downstream of the second outlet In a further aspect is provided a fuel system including a Mel tank fluidly connected to a pump to supply fuel, and including a device as claimed in any preceding claim located downstream of the pump, and wherein said first outlet is fluidly connected back to said tank.

Brief Description of Drawings

The invention will now be described by way of example and with reference to the following figures of which: Figures 1 and 2 show schematically conventional FIE systems; Figure 3 shows a FIE system according to one example of the invention; Figure 4 shows a filtration/separation device according to one aspect of the invention; Figure 5 shows cross-sectional plan views of the top of the container/chamber of figure 4; and Figure 6 shows a filtration/separation device according to one aspect of the invention.

Detailed Description of the Invention

Figure 1 shows schematically a conventional FIE system 1. A fuel tank 2 supplies the system with fuel via a system filter 3 which supplies clean fuel to a transfer pump 4. This pump will generate debris contaminating the fluid, which is supplied to a high pressure pump 5 which provides high pressure fuel to fuel injection components.

Figure 2 shows schematically a conventional FIE system 1 which is the same as figure 1 but includes a second filter 6 to filter debris form the transfer pump.

Figure 3 shows a FIE system according to one example of the invention. Here the problem of dealing with debris from within the pump entering the high pressure system is solved by installing a hydro-cyclone separation device 7 in the filling circuit of the pump, which separates the inflow into two out flows, one which is leaner in contaminants and the other which is richer in contaminants, compared with each other. The outflow which is richer in contaminants, is fed back to the fuel tank via conduit 8.

In this way, contaminated file' enters the hydro-cyclone but potentially damaging particles may be removed before the fuel enters the high pressure system. In fuel pumps with a transfer pump, the hydro-cyclone can be located between the transfer pressure regulator and an Inlet Metering Valve (11\4V). In fuel pumps which fill from the cam box, the hydro-cyclone can be placed between the cam box and IMV.

Figure 4 shows a novel design of hydro-cyclone which can be used to separate a fluid into two components; one component having less particulate matter (e.g. contaminants) than the other. Thus the hydro-cyclone device can be used as a filter and can be used to replace any of the filters used in figures 1 and 2.

The hydro-cyclone generally comprises a housing 10 which forms a chamber 11 with an inlet e.g. an inlet port or conduit 12 located towards one end of the container. The container has a longitudinal axis C and may be generally circular in cross section. Preferably the container is conical in form having a wider cross section at the inlet. The arrangement of the inlet is such that there is a component of flow which is tangential and causes the fluid to form a cyclone or vortex; the overall fluid flow having a net movement towards the opposite end of the container, in the directions of arrows A I and A2. The conical form of the hydro-cyclone causes the rotational motion of the fluid to be accelerated as it approaches the outlet nozzle. With sufficient rotational inertia, particles, (such as contaminants like metal particles), which have higher density than the fuel, are flung outwardly towards inner wall/chamber circumference and are separated from the main flow. The particle path is shown as P. At the other end of the chamber arc located two outlets 13 and 14. One outlet is formed as a relatively large orifice located centrally relative to said chamber axis, the other outlet is formed as an annular orifice, separated from the first outlet by an annular edge or groove 15.

In less refined examples the first outlet can still be located centrally and one or more second outlets are located towards the periphery of the chamber, further away from the central axis.

Figure 5 shows cross-sectional plan views of the top of the container/chamber of figure 4 and show that there may be one inlet 12 (figure 5a) two inlets 12 (figure 5b) or 4 inlets 12 (figure 5c) or indeed any number of inlets, arranged such that there is a component of flow which is tangential relative to the longitudinal axis A when viewed according to the figures; this causes rotational inertia of the fuel in the cyclonic chamber. A vortex is formed with a general net direction shown by arrow A in figure 4 towards the other end of the chamber.

In examples, an important feature is that one outlet (for particle rich outflow) is located further towards the periphery/circumference of the chamber than the other outlet. In other words the outlet for particle rich flow is located further away from the central longitudinal axis than the other outlet. Thereby, particles can be flung towards the periphery via the cyclone (vortex) are generally captured in the exit which is close to the periphery/away from the central axis. In such a way the device act to separate out the inlet into two exit streams, one relatively rich or and the other relatively poor in particles (contaminants). The overall fluid flow through the chamber under pressure means that there is no reliance on gravity.

A preferred example is shown in figure 6 which includes a Venturi /diffuser 16 which is located downstream of the main exit (second outlet) and which minimises energy loss in the nozzle.

When incorporated into a fuel system of figures 3, fuel from the transfer pump or cam box enters the inlet of the hydro-cyclone and whirls around the cyclonic chamber whilst flowing towards the nozzle. Any heavy particles suspended in the fluid have sufficient time to reach the outer wall and are separated by the annular edge/groove. The annular edge/groove is connected to the back leak and returned to tank. in this way, particles are transported away from the device to prevent. re-contamination during periods of low flow. An optional orifice in the return path may be required to restrict flow as excessive flow would cause a significant drop in filling/transfer pressure. Meanwhile relatively clean fuel in the centre of the cyclonic chamber passes through the nozzle and through the optional Venturi (where energy which would otherwise be lost via sudden expansion can be recovered) and on to the 1MV for filling the high pressure pump.

The advantage is that the high pressure components within the pump e. hydraulic head valves and plunger clearance) and all downstream components including the injector, can be protected from debris damage without incurring maintenance costs.

Claims

Claims 1. A filtration/separation device adapted to separate a fluid into at least a first and second outlet streams; said first stream being richer in particulate matter than said second outlet stream comprising: a container which forms a chamber having a central longitudinal axis and being of generally circular cross-section, a fluid inlet means generally located towards one end of said container, and at least first and second fluid outlets located towards the other end of said chamber, wherein said fluid inlet is arranged so as to create a fluid cyclone/vortex within said chamber with a net general flow from said first (inlet) end to said opposite (outlets) end, wherein said first outlet is located generally further away from said central axis compared to the second outlet.
2. A device as claimed in claim 1 wherein said chamber s conical, narrowing towards said outlet end.
3. A device as claimed in claims 1 or 2 wherein said first outlet is located at or adjacent to the circumference of said container.
4. A device as claimed in claims 1 to 3 where said inlet is arranged to provide inlet flow which is tangential
5. A device as claimed in claims I to 4 wherein said second outlet is located generally coincident with the central axis.
6. A device as claimed in claims I to 5 wherein the first outlet is separated from said second outlet by an edge.
7. A device as claimed in claims 1 to 6 wherein said first outlet is formed annular outlet port, surrounding said second outlet.R. A device as claimed in claim 6 wherein said first and second outlets are separated by an annular edge or ridge.9. A device as claimed in claims 1 to 8 which includes a diffuser or Venturi located downstream of the second outlet.10. A fuel system including a fuel tank fluidly connected to a pump to supply fuel, and including a device as claimed in any preceding claim located downstream of the pump, and wherein said first outlet is fluidly connected back to said tank.