GB2103505A - Separator for separating a heavier and a lighter components from a carrier liquid - Google Patents

Abstract

A settling tank especially for separating oil and sand from water, contains a system of inclined plates to increase the separating capacity of the tank. The plates are arranged equally spaced and parallel to each other and to the general direction of the flow through the tank. To enable the use of such a plate system in standard tanks it is built-up from prefabricated plate stack modules (1). <IMAGE>

Description

SPECIFICATION Separator for separating a heavier and a lighter component from a carrier liquid The invention relates to a separator for separating a heavier and a lighter component, especially sand and oil, from a carrier liquid, such as water, the separator comprising a settling tank with an inlet, an outlet, and in the flow path between the inlet and outlet, a system of plates which are oblique in relation to vertical planes, interspaced and parallel to each other and to the general direction of the flow through the part of the tank in which the plate system is situated.

The separation in such a separator takes place by transverse sedimentation and transverse flotation, respectively.

Separators ofthe aforementioned kind are known both in the form of stationary installations below ground level and in the form of prefabricated tanks placed at ground level, and distinguish themselves by a significantly larger separating capacity as compared with clarification tanks, which are only equipped with various forms of vertical partition walls to retain separated media in the tank. This improved separating capacity by means of oblique plates is due to thefactthat lighter components of the liquid such as oil, may rise calmly to the surface, whereas heavier components, like sand, may sink undisturbedly to the bottom ofthe tank, as heights of rise and heights of fall respectively are reduced to the vertical distance between the oblique plates.

As a consequence of the oblique orientation of the plates rising oil droplets and falling sand grains, during their entire movement up towards the surface of the liquid, and down towards the bottom, respectively, are in a boundary layer and do not tend again to be caught and entained bythethroughflowing liquid.

It is common practice for ordinary surface rainwater from city areas to be directed to receiver systems after passage through sand-traps and oil separators in order to reduce the pollution of a receiver.

As the known, specially made settling tanks with plate systems are comparatively intricate and costly they have heretofore only been used for special tasks such as clarification of waste water from industrial plants etc. whereas they, despite their apparent advantages, have found no general application for instance for sedimentation tanks in purifying plants and for purifying rainwater.

It is therefore the object of the invention to devise a separator capable of fulfilling the growing demands on purification of sewage, discharge, surface and other waste water.

The object is achieved by providing the tank as a throughflowtank and constituting the plate system by one or more prefabricated modules of plate stacks.

In practice, the modules will be dimensional to fit into standard mass-produced tanks. Through a combination of a common type of tank and the erection of an oblique plate system by means of prefabricated modules capable of being passed down through the normal openings of the tank and mounted inside the tank by simple means there may be achieved a cheap and effective sand and oil separator, with the consequent environmental advantages. Thus the modules can be placed in existing tanks at insignificant costs and may any time be exchanged without labour consuming digging-ups.

According to one construction a module comprises one or more frames for mounting the plate stack, and the individual plates extend through the frame or frames and are fastened attheirtop and bottom edges to the frame or frames.

A module may be made from various materials like steel, metal, plastics etc. provided that the material proper or a coating thereon is resistant to the media to be treated.

The plates in the module may be plane, somewhat corrugated or have stiffened punchings. Such corrugations and stiffened punchings should be oriented transversely to the direction of the flow through the tank.

The invention will now be explained in more detail, in the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of one plate module; Figure 2 is a vertical section through a complete separator with two plate modules; Figure 3 is a section taken on the line Ill-Ill in Figure 2; Figure 4 is a section through another separator with three rows of plate modules; and, Figure 5 is a diagrammatic perspective view of another plate module.

In Figure 1, is a plate module consisting of two rectangular frames 2 in which and between which are arranged plates or lamellae 3 which are oblique in relation to the sides of the frames. The obliqueness may e.g. be approximately 450.

The plates are arranged in parallel with one another and are equally spaced.

The frames 2 and the plates 3 may be made from plastics, metal or steel, and may either themselves be corrosion resistant towards the liquid composition to be treated or be coated with a material having the desired corrosion resistance.

Dependant upon the material used for the plates and frames the plates may be secured to the frames bygluing,soldering orwelding and if desired the plate edges may fit into small notches in the inner most frame edges, as indicated at 4.

Figures 2 and 3 show an arrangement of two plate modules 1 in a settling tank.

The tank is of a common type, mainly constructed from standard elements, like well-rings 5, a bottom 6, a top cone 7, all in concrete, and with an inlet 8 and an outlet 9.

In the bottom of the tank is a sump 10 for accumu lation of heavier components of the medium such as The drawing(s) originally filed were informal and the print here reproduced is taken from a later filed formal copy.

sewage water to be purified.

The two plastic modules 1 having dimensions enabling them to pass down through the top opening of the tank are mounted above the top edge of the sump, the plates being parallel to the direction of throughflow. The modules may be placed on rods arranged in the direction ofthroughflow and secured to the tank wall, or to partition walls 11, or merely on the top edge of the sump 10 as shown in Figures 2 and 3.

Projections 23 (Figure 1) on the frames 2 are made for retaining the module 1 in a position on two rods mounted at the lowermost corners of the module frames.

In the tank are, at each side of the module sets 1, a partition wall 11 extending all along the interior of the tank down to the top edge of the sump and having rectangular openings 12 corresponding to the circumference of the modules as shown in Figure 3.

The partition walls 11 divide the tank into three chambers, an inlet chamber 13, a separation chamber 14 and an outlet chamber 15.

The settling tank operates in the following way:~ Waste or sewage water is passed to the tank through the inlet 8 and is forced by the first partition wall 11 downwards through the inlet chamber 13, through the opening 12 in the first partition wall 11, through the module plate stacks 3, out through the openings 12 in the second partition wall 11, upwards through the outlet chamber 15 and out through the outlet 9.

During the passage through the plate modules 1 efficient separation takes place partly of lighter, partly of heavier, components such as oil and sand respectively from the sewage water. The lighter components rise along the oblique plates in the modules and gather at the top of the separation chamber 14, whereas the heavier ones sink along the plates and collect in the sump 10.

Figure 4 shows an arrangement of plate modules in a standard tank of a larger type and constructed of rings 16 and having a plane deck 17 with an opening 18. This tank differs from the tank in Figures 2 and 3 in that three rows of plate modules 1 are arranged interspaced side by side. Each row may consist of three single modules 1.

In each ofthe partition walls 11 are openings 12 corresponding to the three rows of modules.

The partition walls 11 in Figures 2, 3 and 4 may be made from plate sections which can also pass the opening 18 for assembling in the tank proper and fastening on its walls.

Figure 5 shows an embodiment of a plate module 19 entirely made from steel.

Each frame consists of two profile irons 20 con nected by bars 21, which bars extend through the corresponding edges of the steel plates 22 and are welded on same, whereas the opposite plate edges are welded on the profile irons. The top and bottom edges of the plates 22 may be bent suitably as shown. The entire module of this embodiment is three ated or coated so as to be corrosion resistant to the medium to be purified.

Claims (3)

1. Aseparatorforseparating a heavier and a lighter component from a carrier liquid, the separator comprising a settling tank with an inlet, an outlet, and, in the flow path between the inlet and outlet, a system of plates which are oblique in relation to vertical planes, interspaced and parallel to each other and to the general direction of the flow through the part of the tank in which the plate system is situated; characterised in that the tank is constructed as a throughflowtank and that the plate system is constituted by one or more prefabricated modules of plate stacks.

2. A separator accordingto claim, characterised in that a module comprises one or more frames for mounting the plate stack and thatthe individual plates extend through the frame or frames and are fastened attheirtop and bottom edges to the frame or frames.

3. A separator substantially as described with reference to any one of the examples illustrated in the accompanying drawings.