GB2280701A - Retainer wall for liquid dispensing system - Google Patents

Abstract

A bund or retaining wall for a liquid dispensing system has a plan view of triangular form, preferably an equilateral triangle, and is moulded in one piece e.g. from a plastics material so as to comprise the three upstanding side panels and a base panel, and optional ledges for supporting a storage vessel above the base panel of the bund. <IMAGE>

Description

RETAINER WALL FOR LIOUID DISPENSING SYSTEM The present invention relates to a retainer wall or so-called bund for a liquid dispensing system, particularly one using aggressive chemicals which need to be contained in the event of leakage from the container vessel.

When handling aggressive chemicals, for example corrosive chemicals, it is considered advisable to avoid human contact with the chemicals, and it has therefore been proposed that such chemicals should be delivered by the manufacturer or distributor to a site of use (the consumer location), where the consumer's static storage vessel will be filled directly from a transport container on the transport vehicle so that the consumer may then use the chemical by drawing it from the storage vessel, as and when desired.

Such a system is, for example, proposed for use in an unmanned remote station, for example where water treatment plants are dosed with small proportions of chemicals which may have various desirable effects on the water. Thus, once the transport operatives have filled the storage vessel and left the site, there will be automatic delivery of the contained chemicals without human intervention.

Particularly in the case of unmanned sites, it is advisable to have some protection in the event of leakage from the storage vessel, for example as a result of failure of any connections to and from the storage vessel or in the event of deliberate damage to the connections or to the vessel itself.

Such secondary containing of the chemical may be by way of a retaining wall or bund effectively defining an open-topped tank in which the storage vessel stands and into which the entire contents of the storage vessel may be transferred in the event of damage to the storage vessel.

Advantageously the volume of the tank defined by the bund is at least 110% of the interior volume of the storage vessel.

It is an object of the present invention to pro vide a bund for a liquid storage system in which the structural strength of the bund is derived from the bending strength of a set of panels, preferably of rectilinear plan form, joined at their ends to other such panels forming corners of the bund. It is intended that the bending strength of the corner joints should not be relied upon to impart structural integrity to the bund.

It is an object of an embodiment of the invention to provide for enhanced bending strength of such bund-defining panels by suitable profiling of the bund panels.

It is a still further object of the present invention to provide for a bund plan form which enables particularly convenient mutual positioning of several such bunds to occupy a compact site, due to the interfitting of adjacent bunds.

It is a still further object of an embodiment of the invention to provide for a bund plan form which can be arranged in association with other similar bunds to allow for the services (for example electrical and hydraulic) to the bunds to be connected at one location of the array of bunds, and then distributed to other parts of the individual bunds by structure within the bund itself.

It is a further object of an embodiment of the present invention to provide for maintained priming of one or more dosing pumps associated with the bund, by mounting the dosing pump at a low location below the level of the floor of the storage vessel within the bund.

In accordance with the present invention we provide a bund for a liquid storage system, comprising a triangular base panel and three upstanding side panels integrally moulded with the base panel, the side panels being joined at their ends to define a triangular planform to the bund.

The appearance of the panels when viewed from above (in the plan view) is rectilinear. In vertical section, the "rectilinear" panels may be of other than recti linear form.

In one advantageous embodiment of the present invention the triangular planform is that of an equilateral triangle.

Preferably the upstanding panels defining the sidewalls of the bund are inclined with respect to an axis perpendicular to the base panel, in such a way that the area enclosed by the planform at the top of the bund wall is greater than the corresponding area at the bottom of the bund wall, thereby facilitating stacking of the bunds one within the other.

More preferably the bund includes integrally moulded ledges on which the storage vessel may stand so as to be clear of the base panel. This maintains the dosing pump(s), to deliver the chemical from the storage vessel, primed by virtue of the hydrostatic head of liquid between the base of the storage vessel and the inlet to the or each dosing pump.

Desirably the cross-section through each of the panels is such that the bund is stepped with at least two parallel panel portions arranged one above the other and joined by a horizontal web portion moulded into the bund.

In order that the present invention may more readily be understood the following description is given, merely by way of example, with reference to the accompanying drawings, in which: FIGURE 1 is a front elevational view of a bund in accordance with the present invention, and showing a liquid storage container positioned in the bund, with inlet and outlet piping and with feed and dispensing pumps; FIGURE 2 is a side elevational view taken from the right side of Figure 1; FIGURE 3 is a top plan view of the assembly of Figure 1; FIGURE 4 is a top plan view of three separate bund and storage vessel assemblies, each of the type shown in Figure 3; FIGURE 5 is a top plan view of the bund alone, after removal of the storage vessel; FIGURE 6 is a side elevational view, taken from the right of Figure 5, of the bund alone; FIGURE 7 is a front elevational view of the bund alone; and FIGURES 8, 9 and 10 are detailed sectional views of the bund alone, taken on the lines 8-8, 9-9 and 10-10 of Figure 5.

As shown in Figure 1, the bund 1 comprises three separate panels 3, 5 and 7 which are disposed one above the other and are joined by a first web portion 9 between panels 3 and 5, and a second web portion 11 between portions 5 and 7. The existence of the web portions 9 and 11 imparts structural rigidity to the panel structure 3-5-7-9-11 which will enable it to resist the bending stresses which may be exerted by liquid filling the bund in the event of a mishap.

Inside the bund is a storage vessel 13 in the form of an upright cylinder having at its top a vent cap 15 and provided with an inlet conduit 17 from a transfer pump 19 the inlet of which is supplied via a flexible transfer hose 21 having at its inlet end a quick release fitment 23 which is able to rest in position on a lug 25 at the top of the bund sidewall panel in such a way that any remaining liquid on the inlet side of the fitment 23 will drip down into the enclosure defined by the bund.

In practice, the fitment 23 may be a quick connect coupling to a lance similar to that disclosed in GB-A-2247451 so that the lance will remain connected to the roof of a transport container, such as a drum, to toe used to fill the storage vessel 13, and then operation of the transfer pump 19 will suck the chemical from that container, and transfer it into the storage vessel 13, by way of the lance and fitment 23 and the hose 21 and conduit 17.

The sidewall of the bund 1 also supports at least one dosing pump 27 which draws liquid from the bottom of the storage vessel 13 and pumps it to the exterior of the bund by way of an outlet conduit (not shown) from the storage vessel 13 to the dosing pump and then by way of another conduit (not shown) from the dosing pump to the exterior of the bund and onward to a consumer apparatus such as a recirculating water system.

Electric power supply to the motors 19 and 27 of the pumps is by way of a main conduit 29 to a junction box or local control panel from which one conduit extends on to the feed pump motor 19 and the other extends to the dosing pump motor 27.

As shown in Figure 1, the inlet conduit 17, in this case a flexible hose, to the storage vessel 13 discharges the incoming chemical horizontally into the vessel 13. The plan view of Figure 3 shows that this inlet hose 17 directs the incoming chemical from an inlet fitment 45 tangentially around the wall of the storage vessel 13 so that it will swirl along the internal wall of the storage vessel and avoid free fall and subsequent foaming in the vessel. Such a vessel is described and claimed in our co-pending application No. 9316338.4 (Folio N.66694). The fitment 45 where the transfer hose 47 from the transfer pump 28 connects to the top of the storage vessel is also within the confines of the bund to provide a degree of protection against leakage.

Although any triangular planform of bund can be used, the equiangular triangle arrangement of Figure 3 is considered to provide a particularly advantageous arrangement in that it is possible to arrange several of the bunds sideby-side such as is shown in Figure 4, with the power supply conduits 29 all coming from a common point adjacent three contiguous corners of the array of bunds. It would, for example, be possible to arrange for another set of three bunds in like array, back-to-back with the array shown in Figure 4 so that all six of the bunds have the power supplies coming from the same point. In such an arrangement the total array of six bunds presents a hexagonal perimeter with the access to each of the bunds on a respective external wall of the bund in question (where each bund has two internal walls and one external wall in the hexagonal array.

Another possibility is for two smaller bunds of equal side length to be arranged with their sides adjacent one side of a larger bund having a side length twice that of the small bunds, optionally with a third small bund interfitting with the first two (i.e. with one vertex adjacent the mid-point of the side of the large bund).

Figure 5 shows a plan view of the bund without the storage vessel in position, and illustrates that each bund has three ledges defined by parallelepiped shaped formations 31, 33, 35 each having a recess 32, 34, 36, respectively, for locating the storage vessel 23 in place. The interior of the parallelepiped-shaped formation 33 is shown in Figures 2 and 6. Likewise, the interior of the parallelepipedshaped formation 35 of Figure 5 is shown in Figures 1 and 7, and the interior of the parallelepiped-shaped formation 31 of Figure 5 is shown in Figure 10.

Figure 5 also shows a further parallelepipedshaped formation 37 which is also visible on the external view of Figure 7. This formation 37 is intended to accommodate, in the external part which is visible in Figure 7, the drive motors 19 and 27 of the feed and dosing pumps 20 and 28 (Figure 3), respectively.

Given that all three of the sidewall panel portions 3, 5 and 7 have the same vertical height, and that the tallest of the parallelepiped-shaped formations (formation 37 to accommodate the pump drive motors) only extends over the height of the bottom two panel portions 5 and 7, the bunds can be stacked for storage purposes with the base panel 2 of one bund resting on the top of the motor-receiving formation 37 of the next underneath bund. This will then allow two bunds to be stacked such that the total height of the stack of two is only the depth of one of the three panels 3, 5 or 7 greater than the height of the single bund, and this will provide a considerable saving when a larger number of bunds is stacked in this way.

Although the arrangement shown in Figures 5, 6 and 7 uses parallel sidewall portions 3, 5 and 7, and although the parallelepiped-shaped formation 31, 33, 35 and 37 are all given vertical sidewalls, it would alternatively be possible to enhance the nesting effect by giving each of the parallelepiped-shaped formations 31, 33, 35 and 37 an upwardly tapering form so that further nesting can result in having the formations 31, 33, 35 and 37 of one bund at least partially nesting over the corresponding formations of the next bund therebelow.

A recess 39 in Figure 5 to receive the power supply conductor 29 of Figure 3 can be seen in Figure 10 as being formed by a right angled corner in the moulding crosssection.

The bunds must be capable of withstanding the same aggressive chemicals as the storage vessel 13 itself, so it is preferable for the bund to be made of the same material as the storage vessel 13. Indeed, it is conceivable for the bunds to be injection moulded from recycled polypropylene, or medium or high density polyethylene previously used for moulding the storage vessels 13 or similar containers.

An advantageous detail of the design of the bund resides in the fact that the dosing pump 28 is positioned low down on the bund wall so that there will always be a head of liquid above the pump 28 to maintain the pump primed. Likewise, the lug 25 with its recess to hold the inlet fitment 23 of the transfer hose 21 is higher than the location of transfer pump 28 (see the position of its drive motor 19 in the front elevation of Figure 1) to maintain the transfer pump 19 primed at all times.

Likewise, it is considered advantageous that the two pumps 20 and 28, constituting the wet end of the pumping system, are located within the bund perimeter as also are all of the connections to the hoses 17 and 21, and the wet end of the inlet fitment 23, so that there will be no spillage of the aggressive chemical outside the bund and hence no danger to operatives moving around outside the bund.

Equally, the electric power supply conduit 29 and the entire assembly of the feed pump motor 19 and the dosing pump motor 27 are located outside the bund, but within the parallelepiped-shaped formation 37 providing a safe recess for it, with the result that the motors with their electric supplies (which might possibly give rise to a fire risk if they came into contact with any flammable chemicals being handled) are all on the dry side of the bund wall, and by being mounted in the formation 37 they do not impede the ability to arrange bunds side-by-side as shown in Figure 4.

Equally, the mounting of the motors and lateral connections on the outside of the bund enables maintenance of those components to be carried out without the operator needing to come into contact with any leakage or spillage on the (wet) inside of the bund. Such an arrangement of bund assembly is described and claimed in our co-pending application No.

9316339.2 (Folio N.66693).

Although Figure 4 shows three bunds of equilateral triangle formation and identical size arranged together, it is of course possible for various different sizes of equilateral triangular-shaped bunds to be arranged together, for example by having two sizes with the side length of one size half that of the other size.

Where a triangle other than an equilateral triangle is used it may be advantageous to use a right angled triangle so that the right angle in question may be aligned with the corner of a building where the bund 1 and its associated storage vessel 23 are to be located.

Although the bund illustrated in the drawings uses hoses 17 and 21, at least the fluid conduit 17 could instead be a substantially rigid pipe.

Claims (11)

1. A bund for a liquid storage system, comprising a triangular base panel and three upstanding side panels integrally moulded with the base panel, the side panels being joined at their ends to define a triangular planform to the bund.

2. A bund according to claim 1, wherein the side panels have a cross-section including portions extending generally parallel to said base panel of the bund, for enhancing the bending strength of the side panel.

3. A bund according to claim 2, wherein each of the side panels comprises three generally parallel side panel portions of substantially identical length and mounted one above the other and joined by respective said portions parallel to said base panel.

4. A bund according to any one of the preceding claims, wherein the triangular planform of the bund is that of an equilateral triangle.

5. A bund according to any one of the preceding claims, and including integrally moulded ledges providing for mounting of a storage vessel in the bund above the floor level of the bund.

6. A bund according to any one of the preceding claims, wherein the side panels are formed so as to permit nesting of one bund within an identical bund therebelow.

7. A bund according to any one of the preceding claims, and further including an inwardly extending formation to house a drive motor of at least a dosing pump controlling withdrawal of liquid from a storage vessel to be enclosed by the bund, whereby the drive motor may be entirely located within said formation so as to lie within the perimeter of the upstanding wall panels of the bund.

8. A bund according to either of the preceding claims, and including at least two pumps, namely a transfer pump for transferring liquid into a storage vessel to be confined by the bund and at least one dosing pump for delivering liquid from a said storage vessel to the exterior of the bund, each said pump including a drive motor and a pumping section, with the pumping section mounted on the inside of the bund sidewall and the drive motor on the outside of the bund sidewall, the pumping section being sealed to the bund and joined to the drive motor by a drive shaft for the pumping section.

9. A bund according to claim 8, including (a) a storage vessel mounted within the bund; (b) a transfer hose connected at one end to the transfer pump and having at the other end a fitment for attachment to a transport container; (c) a feed conduit connected at one end to said transfer pump and at the other end to said storage vessel at a point near its top; and (d) a delivery conduit connected at one end to the bottom of said storage vessel and at the other end to said at least one dosing pump, wherein said connections of the delivery conduit to the or each dosing pump and to the storage vessel and of the feed conduit to the transfer pump and to the storage vessel, and of the transfer conduit to the transfer pump are all located directly above the base panel of said bund.

10. A bund according to claim 9, and further including a lug to support the other end of said transfer hose remote from the transfer pump, when transfer of liquid to said storage vessel from a transport container has been completed.

11. A bund for a liquid dispensing system, substantially as hereinbefore described with reference to, and as illustrated in, the accompanying drawings.