GB2245609A

GB2245609A - Grease trap

Info

Publication number: GB2245609A
Application number: GB9014741A
Authority: GB
Inventors: Anthony Patrick Richard Coates
Original assignee: ENTEC
Current assignee: ENTEC
Priority date: 1990-07-03
Filing date: 1990-07-03
Publication date: 1992-01-08
Also published as: GB9014741D0

Abstract

A grease trap comprises a water tank 1 having an inlet 3 for connection to the waste water outlet of the kitchen of a premises, and an outlet 5 for connection to the drainage system of the premises. A series of inclined parallel plates 11, formed by oil absorbent cloth stretched over a framework, is positioned in the tank 1. In use of the grease trap, the series of inclined plates 11 encourages laminar flow of waste water entering the tank through the inlet 3, globules of oil rising through the water between the plates to be absorbed by the oil absorbent cloth. <IMAGE>

Description

GREASE TRAP This invention relates to grease traps. In particular the invention relates to grease traps of the kind which are typically connected to the waste water outlet of the kitchens of premises such as restaurants or hotels, so as to intercept grease in the waste water and preventing the grease from entering the drainage system for the premises.

Known grease traps for use in such situations comprise a tank having an inlet for connection to the waste water outlet of a premises, and an outlet for connection to a drainage system for the premises. The tank contains a baffle means for directing the flow of waste water from the inlet, so as to reduce turbulence of the water in the tank. In use of such a grease trap, the waste water within the tank is allowed to cool such that grease and fats within the waste water separate out and rise to the surface of the water, the resultant scum being prevented from being washed out of the tank through the outlet by means of an outlet baffle connected to the outlet.

With the increased use of vegetable oils in cooking rather than lards and fats, such known grease traps become ineffective in that vegetable oils stay in suspension in the waste water for longer, and therefore can pass straight through the grease trap, thus causing problems in the drainage system down-line of the trap.

This is a particular problem where the premises are not on a mains drainage system, as the grease may severely impair the operation of a treatment plant or septic tank.

It is an object of the present invention to provide a grease trap which is suitable for use with vegetable oil.

According to the present invention a grease trap comprises a tank having a liquid inlet, a liquid outlet, and a series of parallel plates orientated within the tank between the inlet and the outlet such that liquid passing through the inlet into the tank is directed into a laminar flow pattern by the plates, with oil globules in the liquid rising upwardly between the plates towards the surface of the liquid in the tank, the parallel plates incorporating respective oil absorbent surfaces.

The series of parallel plates suitably comprises a framework over which an oil absorbent cloth is stretched.

A strainer basket is suitably arranged in the flow path of liquid from the inlet of the tank so as to strain out solid matter in the liquid, whilst an outlet baffle is suitably arranged in the flow path of liquid in the tank to the outlet, so as to prevent scum from being washed out of the outlet.

One embodiment of a grease trap in accordance with the invention will now be described, by way of example only, with reference to the accompanying figure which is a schematic cross-sectional view of the grease trap.

Referring to the drawing, the embodiment of the grease trap comprises a casing defining a water tank 1, the tank having an inlet 3 and an outlet 5. A galvanised strainer basket 7 is positioned in the tank adjacent to the inlet 3, an outlet baffle 9 being positioned adjacent to the outlet 5.

Within the tank 1, there is provided a framework over which is stretched an oil absorbent cloth, the framework and cloth being effective to constitute a series of parallel plates 11, the plates being inclined relative to the tank 1, as shown in the Figure.

In use the grease trap is installed in the ground with the inlet 3 connected to the waste water outlet of the kitchen of a premises, and the outlet 5 connected to the drainage system for the premises, prior to the point where other foul waste enters the drainage system. The tank 1 is normally covered by two manhole covers 13,15 mounted on a frame 17 at the top of the tank 1.

Thus, waste water from the kitchen will enter the tank 1 through the inlet 3, initially passing through the strainer basket 5 where solids within the waste water will be collected. The flow of water is then directed by the first plate within the series 11 and the shape of the casing, to the base of the tank. The series of inclined plates 11 encourages laminar flow of the waste water, globules of oil within the waste water being encouraged by this flow to rise in the water towards the next #plate within the series 11, where the globules of oil are absorbed on to the surface of the oil absorbent cloth. Any oil globules reaching the surface of the water in the tank are collected either by the last plate within the series 11 which is arranged to be proud of the water level of the tank, or by the outlet baffle 9.

Periodic inspection of the grease trap, typically at fortnightly intervals, may be made by removal of the manhole covers 13,15. The series of plates 11 may then be removed and the oil absorbent cloth replaced when necessary, and the strainer basket 7 emptied when necessary.

It will be appreciated that a grease trap in accordance with the present invention finds particular application in the interception of grease from kitchens of premises such as restaurants or hotels. The invention will, however, also find application in other situations where it is necessary to remove oil globules from a liquid which may be other than water, for example in the drainage systems of chemical laboratories.

Claims

1. A grease trap comprising a tank having a liquid inlet, a liquid outlet, and a series of parallel plates orientated within the tank between the inlet and the outlet such that liquid passing through the inlet into the tank is directed into a laminar flow pattern by the plates, with oil globules in the liquid rising upwardly between the plates towards the surface of the liquid in the tank, the parallel plates incorporating respective oil absorbent surfaces.

2. A grease trap according to claim 1 in which the series of parallel plates comprises a framework over which an oil absorbent cloth is stretched.

3. A grease trap according to claim 2 in which the cloth is replaceable on the framework.

4. A grease trap according to any one of the preceding claims in which a strainer basket is arranged in the flow path of liquid from the inlet of the tank, so as to strain out solid matter in the liquid entering the tank.

5. A grease trap according to any one of the preceding claims in which an outlet baffle is arranged in the flow path of liquid in the tank to the outlet, so as to prevent scum from being washed out of the outlet.

6. A grease trap, substantially as hereinbefore described with reference to the accompanying drawing.