GB2514329A - Improvements in and relating to oil and light liquid separators - Google Patents

Abstract

A water filtration apparatus (1, Fig. 1) includes a tank 2 having a contaminated water inlet pipe 3 and a purified water outlet pipe 4, wherein the tank is separated into first 6, second 7 and third (9, Fig. 1) chambers. The first and second chambers are separated by a hollow filter wall 5 having diagonally opposite openings at respective ends permitting contaminated water to flow from the first chamber into the opening 18 and along the inside of the filter wall to its other end to thereafter flow out of the other opening 19 into the second chamber. A coalescent filter 13 between the second chamber and the third chamber supplies purified water to the purified water outlet pipe. Suitably, the coalescent filter is an open-meshed filter mounted on a perforated tube 11 having an exit end in direct fluid communication with the third chamber. In one embodiment, the apparatus includes a floatable skimmer 20 within the first chamber to suck oil or light liquid from the surface of the water via a suction pump.

Description

This invention relates to the separation and removal of oil and light liquids from water, such as rainwater mixed with oil or light hquids in open bunds.

Various techniques are known to separate oil from water, includinq the S use of coalescent fillers which trap or entrain contaminants in water and can be very efficient if regularly maintained or replaced but become less efficient when clogged, whether by the gradual buila up of the contaminant oil or light liquid or where there is a sudden surge from a major spill.

The present invention is derived from the realisation that there is a need to address the foregoing oroblems by providing l9ltration apparatus capable of operating in all conditions and in which the foregoing disadvantages are obviated.

According to the invention there is provided contaminated water filtration apparatus incuding a water tank having a contaminated water inlet pipe and a purified water outlet pipe, the tank being separated into first, second and third chambers, the first and second chambers being separated by a hollow filter wall having diagonally opposite openings at respective ends permitting contaminated water to flow from the first chamber, into the opening and along the inside of the filler wall to its other end to thereafter flow out of the other opening into the 2.0 second chamber, and a coalescent filter between the second chamber and the third chamber for supplying purified water to the purified water outlet pipe, Preferably, the coalescent filter is an open-mesh filter mounted on a perforated tube having an exit end in direct fluid communication with the third chamber, within which perforated tube is slideably disposed a float below which is mounted a tube closure means, such as a plug, or stopper, the buoyancy of the float being arranged such that when floating in light liquid, such as oil, It sinks to the bottom of the tube, thereby dosIng It. With this arrangement the filtration apparatus can operat, to continuously provide filtered water through the use of the filter wall and the coalescent filler, but in the event of e.g. an oil spIllage'ovarwhelming the filtration apparatus or in the event of e.g. an unwanted build up of contaminated water downstream of the fitter wall the float and associated closure means act to automatically shut off the flow of contaminated liquid to th. third chamber and hence the ouSt It) Conveniently, the filtration apparatus also Indudes a floatable oil or light liquid skimmer and associated pipe thraugh which oil or light liquid may be sucked out from the surface of the reseivoir via a suction pump, which may Itself be automatically triggered in response to closure of' the San water' outlet, by the closure means of the float within the perforated tubs). to thereafter divert oil or light liquid to e.g. a large capacity holding tank.

The invention will now be described, by way of example only, with reference to the accompanyrng drawings, in which: Figure 1 Is a pact-cut away side elevation of filtration apparatus IncludIng a. lifter wall, Agure 2 Is a cmss-sectionai view of the filter wall of Figure 1 along the axis X' -X' of Figure 1, Figure 3' Is a plan view of the apparatus of Figure 1 but including an oil, or light liquid skimmer apparatus, and FIgure 4 is a side view of the skimmer apparatus shown in Figure 3.

Referring firstly to Agure 1, filtration apparatus shown generaUy at I comprises a filtration tank.2 having a contarnnated water inlet pipe 3 and a purified water outlet pipe 4, between which are disposed a rectangular hoflow filtration wall 5, typically made of dropstitch or other tibrousstrand inner material, which splits the tank 2 into first and second chambers 6, 7 as shown in Figure 3 and is mounted on a base plate 8 deflning the upper part of a third, pure water, exit chamber 9 and associated exit pipe 10 (shown in broken outline), although the shape of the third chamber may instead correspond to a pipe where eq. downward flow of pure water is required, Mounted centrally on the base plate 8 is a perforated tube 11 having an inwardly lipped outlet end 12 surrounded ny an annuar coalescent filter 13 of open4nesh material such as reticulated foam sponge materiaL Within the perforated tube 11 is disposed a slideable float 14 from which depends a plug or stopper 15 for, in use, closing the Upped end 12 of the perforated tube 11.

15. As can be Seer) more clearly with reference to Figure 3, on the inside of the tank 2 adjacent the contaminated water inlet 3 is an inlet box 16 and associated water outlet duct 17 for directinq incoming contaminated water (shown arrowed) radiafly within the first chamber 6 towards an inlet opening or vent 18 at one end of the filter wail 5, which filter waD 5 also includes an outlet opening or vent 19 at its diagonaDy opposite other end, between each of which openings 18, 19 can flaw water as it is being filtered.

Within the first chamber 6 is a floatable skimmer 20 in the form of a funnel connected to radially disposed floats 21 by which the upper surface at the skimmer 20 can float on top of water in the manner as shown in Figure 4 and into whidh contaminants such as cii or light liquIds may flow, to be thereafter sucked out via an outlet pipe 22 and associated suction pump (not shown) to safe storage.

In operation contaminated water shown arrowed enters the inlet box 16 via the inlet pipe 3 and exits through the opening 17 into the first chamber 6 whereafter any entrained oil or emulsified Water that has not been captured by the skimmer 20 flows through the water inlet 18. of the hollow fitter wall S and passes through strands or fibres which tend to entrain the oil or other Hght liquid contaminants untU they coalesce to the extent of eventually floating to the surface to be then captured by the skimmer 20. The flow of water proceeds through to the outlet opening 19 d the filter wall 5 to thereafter enter the second chamber. with its attendant coalescent filter 13. This further traps or entrains contaminants within the water, whereafter dean water leaves via the lipped end 12 of the perforated tube 11 in the manner as shown in Figure 1, to enter the third chamber 9 from which It exits via the exit tube 10 and exit pipe 4 In the manner as shown arrowed.

In the event that the fifter apparatus I becomes overwhelmed with a surge of e.g. oil from a major oil spill, or due to an accumulation of oil because of lack of maIntsnarue the float. 14 Stnks downwards towards the lipped end 12 of the perforated tube 11 as It loses buoyancy due to the presence of lighter than water liquids to the point where the plug or stopper 15 blocks the tipped end 12 of the perforated tube Il thus acting as an automatic closure device for the filtration, apparatus 1.

Claims (6)

1. SClaims 1. A contaminated water filtration apparatus including a water tank having a contaminated water rnlet pipe and a purified water outlet pipe, the tank berng separated into first, second and third chambeis, the first and second chambers being separated by a hollow filter waU having diagonafly opposite openings at respectiVe ends permittihg contaminated water to: flow from the first chamber, into the opening and along the inside of the filter wall to its other end to thereafter flow out of the other opening into the*cond chamber, and a coalescent filter between the second chamber and the third chamber for supplying purified, water to the purified * water outlet pipe.
2. 2. Apparatus according to claim 1 wherein the coale cent filter is an open C?) mesh filter mounted *on a perforated tube having an exit end in. direct fluid communication with the third chamber, within which perforated tube is shdeably disposed a float below which is mounted a tube closure means, such as a plug ci stopper, the buoyancy of the float being arranged such that when floatng in light liquid, such as oil, it sinks to the bottom of the tube, thereby closing it,
3. 3. Apparatus according to claim 1 or claim 2 wherein, the filtration pparatus also includes a floatable oil or fight Uquid skimmer and associated pipe through which oil or light liquid may be sucked out from the surtace of the reservoir vIa a.suction pump.
4. 4. Apparatus according to claim 3 wher&n the suction pump is automatically triggered in response to closure of the clean water outlet by the closure means of the float within the perforated tube, to thereafter divert oil or Ught liquid to eg.a large capacity holding tank.
5. 5. FVt.raton apparatus substanSy as. hereirthefore described with reference to Fiqures 1 to 3.
6. 6. Skimmer apparatus substantiaHy as hereinbefore described with reference to Figures 3. and 4.CO L() (4