GB2341340A

GB2341340A - Moulding containers with baffles

Info

Publication number: GB2341340A
Application number: GB9819659A
Authority: GB
Inventors: James Marshall; Stephen Smith
Original assignee: OASIS WATER GARDEN PRODUCTS LI
Current assignee: OASIS WATER GARDEN PRODUCTS LI
Priority date: 1998-09-09
Filing date: 1998-09-09
Publication date: 2000-03-15
Also published as: GB9819659D0

Abstract

A method of manufacturing by rotary moulding an open top container (see figure 4) having an upright baffle which does not extend down to the bottom wall of the container comprises inserting through an aperture (160), in a side wall of a hollow mould (170) used for the rotary moulding, a former (140) for the baffle, coating inner surfaces of the hollow mould (170) and the surface of the former (140) with plastics material by rotary moulding, removing the former (140) from the hollow mould (170) and removing the moulded container from the hollow mould (170). The container may be use as a water filtration tank for filtering water for a fish pond, the baffles acting as weirs.

Description

2341340 A MIETHOD OF MANUFACTURING CONTAINERS WITH BAFFLES This invention

relates to methods of manufacturing containers with baffles.

Baffles, consisting of barriers which incompletely divide two compartments in a moulded container, some leaving a gap between the top of the baffle and the top of the compartments and some leaving a gap between the bottom of the baffle and the bottom of the compartments, are commonly known. One application for these baffles is as weirs in water filtration systems where successive compartments contain different types of filter media, but the water must flow through each compartment and under and over the weirs in order to be fully cleaned.

Currently baffles extending to the bottom of the container can be moulded with the container but baffles which must have a gap beneath them cannot be so moulded and these baffles are inserted after the outer part of the container has been moulded, being bolted to the outer part using metal bolts and sealing washers.

This task can take a skilled mechanic a considerable time and the resulting baffles may be the least reliable part of the resulting system they may suffer from leaks at the washers and the bolts may rust.

This invention provides a method for manufacturing containers having interior baffles by rotary moulding, the method comprising the steps of.

positioning a former through an aperture in the wall of a mould; coating of the interior surfaces of the mould, including the outer surfaces of the former, with a plastics container material; by heating and rotating the mould; removing the former through the aperture in the mould wall; and removing the moulded container from the mould.

In this invention the baffles are moulded as an integral part of the main container. At least one removable former strip is placed in the main container mould such that plastics material placed in the mould coats all of the surfaces including the former strip, as the mould is rotated and heated during moulding. A tubular or hollow baffle is thus formed which is lighter and more reliable than Ihe standard baffle. The former strip is then removed, the mould is opened and the container parted from the mould. This method is particularly convenient to accomplish when the former is placed through holes in the walls of the mould, 2 which are substantially opposite each other. Advantageously two open top containers are moulded as one with one container inverted and abutting the other, the containers being subsequently separated.

This invention also provides a container comprising an outer wall with interior moulded baffles extending across and forming an integral part of the container, such baffles being substantially hollow.

This invention also provides an integral vortex, moulded to one end of the container having integral baffles in which the moulded joint between the vortex and the container forms a weir over which the water must flow from the vortex to reach the container.

An embodiment of the invention comprising a water filtration tank, particularly suitable for filtering water for a fish pond, will now be described with reference to the accompanying drawings, throughout which parts are referred to by like references and in which:

Figure 1 is a schematic top view of a water filtration tank and vortex containing baffles; Figure 2 is a schematic cross section corresponding to Figure 1; Figure 3 is a schematic view of a mould for the tank and a former to form a baffle; and Figure 4 shows in schematic form the finished tank complete with vortex and container with moulded baffle.

Figures 1 and 2 illustrates the filtering action of a water filtration system.

Ile water enters a vortex 20 through an inlet 10. The vortex consists of a circular chamber of plastics material 30. The water is caused to circle around the vortex, leaving by flooding over a weir 40 while entrained solids fall to the bottom. The water flowing over the weir 40 enters a filter tank 25 and then flows down through a first filter medium 40, which is separated from a second filter medium 50 by a first baffle 30, which is spaced from the bottom of the container and under which the water must flow. Each filter medium rests on supports 80. A second baffle 60, arranged in the opposite sense from the first baffle 30 separates the second filter medium 50 from a third filter medium 70 and so on. In this way it is possible to filter the water through many different types of media conveniently arranged in the 3 one tank. Having been filtered the water flows down in the last compartment and out through an outlet 80.

Figure 3 shows the first step in this method of manufacturing moulded baffles in a container of the general form shown in Figure 1. A mould 170 for the container 20 and 25 is designed so as to manufacture two containers at one time and so has at least two slots 160 in each side in which are placed former strips 140.

Plastics material powder precursor is placed in the mould 170 and it is sealed shut. When the former strips are in place the mould 170 is heated and rotated causing the plastics material to cover all interior surfaces of the mould, forming a hard shell on the surfaces as it cools.

In order to remove the containers the former strips are first slid out of their slots. The mould is then unclamped and the two halves separated at plane 150 as indicated in Figure 3 by moving the two halves in opposite directions. The containers are then conveniently separated from each other by bandsawing along the plane 150 as indicated in Figure 3. A finished container made by this method is illustrated in Figure 4.

If

Claims

1. A method for manufacturing by rotary moulding a container having an interior baffle moulded as an integral part of the container, the method comprising the steps of positioning a former through an aperture in the wall of a mould; coating the interior surfaces of the mould, including the outer surfaces of the former, with a plastics container material by loading plastics material into the mould and heating and rotating the mould; removing the former through the aperture in the mould wall; and removing the moulded container from the mould.

A method according to Claim 1, in which two open topped containers are moulded simultaneously with the open tops abutting and the method includes the step of separating the two containers after moulding.

3. A container moulded by the method of Claim 1 or Claim 2, comprising an outer wall with at least one interior moulded baffle extending across and forming an integral part of the container, such baftle being substantially hollow and spaced from a bottom wall of the container.

4. A container according to Claim 3, formed as a generally parallelipipedal tank.

5. A container according to Claim 4, including an integral vortex bowl moulded to one end of the tank with a moulded joint between the bowl and the tank forming a weir over which water must flow from the bowl to reach the tank.

6. A container according to any one of Claims 3 to 5, formed as a water filtration tank particularly suitable for filtering water for a fish pond.

7. A method as claimed in Claim 1 and substantially as hereinbefore described.

Ir

8. A container substantially as hereinbefore described and illustrated with reference to the accompanying drawings.