GB2367943A - Battery container - Google Patents

Abstract

A battery container 1 for sub-surface installation is provided with a domed removable lid 8 which is sealable to the container, the lid 8 being provided with a fluid venting outlet 14 at its apex, and a fluid inlet 18 spaced therefrom and also adapted to accommodate power cables 42, in use hydrogen generated by the charging of the batteries being dispersed through the outlet 14 for safe discharge at a remote location, <I>ie</I> the surface.

Description

BATTERY CONTAINER

This invention has reference to a battery container for accommodating batteries such as are used in cable network systems employed in urban and suburban conurbations for the supply of cable television and like communications.

The provision of batteries is required in order to ensure continuity of supply and necessarily the batteries have to be maintained in a fully charged condition in order to perform their designated function satisfactorily. It is conventional practice to house the batteries in appropriate cabinets on the surface adjacent the control equipment array which is also contained in a secure cabinet at the side of the thoroughfare, usually on or by the pavement, walkway or road.

There is generally a relatively small amount of space next to walkways which is often taken up by other communications boxes, for example telephone junction boxes, and furthermore there is a security aspect which dictates that relatively strong vandalproof and weatherproof constructions are adopted.

Moreover, as is well known, the charging of batteries occasions the generation of hydrogen gas which, although in relatively small amounts, represents a potential explosion hazard unless appropriate precautions are taken.

An object of the invention is therefore to provide a battery container which is adapted to afford a safe and secure protection for batteries being charged in situ.

A further object of the invention is to provide an installation of such a battery container.

According to a first aspect of the invention a battery container for subsurface installation includes a housing of sufficient internal volume to accommodate a number of batteries, the housing having a base and a side wall leading to an opening in the top of the housing, a releasable closure member for the opening provided with sealing means for sealing registration with the opening, the closure member being provided with a fluid venting aperture and an inlet aperture for cables and fluid, and the closure member being profiled internally thereof such as in use to assist the flow of fluid towards the venting aperture.

The housing may be cylindrical with a circular top defining the opening, which may be provided with a mating formation for positive registration with the sealing means on the releasable closure member. The sealing means is preferably of simple type to avoid the need for difficult closure and maintenance and accordingly may consist of an 0 ring seal, and a clamp may be provided for positively securing the closure member to the housing.

The closure member may be dome-shaped or of concave form and the fluid venting aperture may conveniently be disposed at or substantially at or adjacent its topmost point with the inlet aperture being formed at a position spaced from the venting aperture. The venting aperture is intended as an exhaust outlet for the gas produced in use upon charging the batteries, the exhausting gas usually being a mixture of hydrogen and

air. The inlet aperture may have associated therewith a tube which with the closure member in position sealing the opening of the housing extends

into the volume of the housing at a level below that of the venting aperture. The cabling for the batteries passes through the inlet aperture and through the tube when provided, and purge air will also pass through the inlet aperture into the chamber defined by the housing.

The housing may be provided internally thereof with a divider located at a distance from its base, the divider being adapted to support a platform which thus affords a two-tier arrangement for the batteries with some disposed on the base and others on the platform. In practice the batteries would be connected in series with only two cables extending through the inlet aperture.

The shape of the housing may be other than cylindrical, for example square or rectangular, in which case the closure member would be of hollow pyramidal shape thus providing an apex at or close to which the venting aperture would be located.

Pipes may be provided and form a releasable and renewable part of the battery container, the pipes being sealably connected to respective apertures for providing in use conduits between the container and a surface location.

According to a second aspect of the invention there is provided an installation for a bank of a batteries including a battery container according to the first aspect of the invention, a sub-surface well within which the container is adapted to be accommodated, a securable cap for the well, pipes for connection to the closure member of the container, and exit points provided in the well for the passage of the pipes therefrom to a surface location.

The surface location may be constituted by a cabinet into which in practice the pipes are led, with the final section of the pipe attached to the inlet aperture being preferably disposed horizontally and the pipe attached to the fluid venting aperture is conveniently orientated vertically with a protective cover to prevent the ingress of extraneous material.

The objective of the installation and more particularly the battery container is to allow the safe discharge of hydrogen gas from the chamber defined by the container venting to atmosphere remote from the primary source of ignition.

By way of example only, one form of battery container and installation thereof is described below with reference to the accompanying drawings in which: Figure 1 is a front elevation of the battery container; Figure 2 is a schematic view of the battery container; Figure 3 is a schematic view of an installation; and Figure 4 is a schematic view of a further part of the installation of Figure 3.

Referring to the drawings, there is shown a battery container 1 of hollow cylindrical form with a defining wall 2 having a base 4 and an upper open end 6, a chamber 7 being formed therewithin. The base 4 is of sufficient strength to support internally of the container a number of batteries which may be arrayed in any appropriate manner. In another embodiment (not shown) of the invention the batteries may be arranged in tiers with one or more suitable intervening platforms for the upper echelon (s) of batteries, a corresponding number of supports being provided within the container at appropriate levels.

A closure member in the form of a lid 8 having a lip 9 which fits over the outer top margin of the wall 2 of the container 1 for releasably closing and sealing the open end 6 thereof. An 0-ring seal (not shown) is provided for sealing relationship between the lid 8 and the outer top margin of the wall 2 of the container and a clamp 10 is reeved around the lip 9 such that in use the 0-ring seal affords a substantially air-tight fit between the lid 8 and the container 1.

The lid 8 is dome-shaped and rises from the lip 9 to its apex 12 whereat is formed an outlet 14 having a gland (not shown) for connection to a pipe 16 for the egress, in use, of fluid from the chamber 7 of the container 1.

An inlet 18 is disposed in the lid 8 at a location spaced apart from the outlet 14 and also has a gland (not shown) for connecting an external pipe 20 and an internal tube 22 which terminates at some distance below the lid 8 and within the volume of the chamber 7.

In use the container 1 is disposed within a well 30 of a manhole located at a sub-surface level and being closable by a lockable man-hole cover 32, the well preferably being defined as a casing of protective material, for example concrete which is sunk into the ground 34. The defining wall of the well 30 has at least two apertures 36,38 for the passage of the pipes 16,20 extending from the outlet 14 and the inlet 18 in the lid 8 of the container 1. Sand bags (not shown) may be provided around the container in any unoccupied space for added protection, particularly in an area noted for flooding, as they will assist in preventing the container 1 from floating within the well 30.

Batteries 40 are placed in the bottom of the container 1 and power cables 42, which may be armoured, are passed through the pipe 20 and the tube 22 and connected to the terminals (not shown). The battery terminal bolts should preferably be fitted with shake proof washers and two lock

nuts. Furthermore, as a preference a duplicate connection should be made so that arcing does not occur if one connection fails. The pipes 16,20 are led to the surface 50 and emerge within a cabinet 52 diagrammatically shown in chain link outline in Figure 4 where they are attached to a mounting plate 54 with the outlet pipe 16 being orientated vertically and terminating in a perforated end 60 with a protective cowl 61 arranged over the open end to prevent the ingress of solid or liquid contaminants. The inlet pipe 20 emerges vertically within the cabinet 52 and then assumes a horizontal orientation from which the cables 42 extend and are connected to a power supply 56.

In practice the charging of the batteries 40 generates hydrogen gas which becomes part of the atmosphere within the chamber 7 and which mixes with the air. As hydrogen is lighter than air, the mixture tends to rise within the chamber eventually to exhaust through the outlet 14 at the apex of the lid 8 and into the pipe 16 whence it flows upwardly to be discharged safely in a diluted state to atmosphere through its open and perforated end 60 within the cabinet 52.

Consequent upon the flow of the air/hydrogen mixture through the pipe 16, air is induced into the chamber 7 through the pipe 20 and thus through the inlet in the lid 8, thus contributing to the purging of the chamber of a potentially explosive gaseous mixture.

The hydrogen thus generated within the chamber 7 is confined within the container 1 and exhausts safely through the pipe 16 from where it is dispersed to the atmosphere at the surface level. Additionally, in view of the provision of an inlet to the chamber 7 an air purge is established which further enhances the safety attaching to the invention.

There is thus established a convection current within the chamber 7 which will also serve to extract any moisture that is formed during the process or otherwise. In addition diffusion occurs whereby as the random movement of hydrogen molecules inside the container 1 brings them underneath the outlet 14, a finite probability exists that the molecule will drift up into the pipe 16 and will flow therethrough ultimately to discharge to atmosphere, even if one of the pipes is blocked.

The inventors have prepared a mathematical model relating to dimensions and the performance of the container. This model (hereinafter being referred to as'the model as defined herein') is set out below and addresses the convection and diffusion mechanisms associated with gaseous fluid behaviour.

The Model

Where: e is the equilibrium hydrogen concentration, as a percentage H is the hydrogen generation rate, in cc/min A is the area of the pipe 16 in mm2 H is the height of the exit end 60 in m J is the'Diffusion Constant'Typical Value = 0.00645 cr is the'Convection Constant'Typical Value = 0.0024

It has been found by experimentation that the correlation between the model and the measured results is high, in excess of 0. 68 and generally being in the region of 0.90 and above.

The present invention therefore provides in the first aspect a container for safely housing batteries at sub-surface level and in the second aspect an installation incorporating the container whereby any hydrogen generated as a result of the charging process is dispersed without risk and in an efficient manner.

It will be understood that the container may be produced from any suitable corrosion-resistant material, for example plastics material, having a degree of rigidity and of reasonable strength.

Whilst the container has been described specifically in relation to its installation within a well constituted by a standard manhole, it will be understood that the container may be merely inserted in a hollow formed in the ground and subsequently covered with earth rather than a manhole cover.

The pipes connected to the inlet and the outlet are equally of sufficient strength to withstand ground pressure without rupture.

Claims (14)

1. A battery container for sub-surface installation includes a housing of sufficient internal volume to accommodate a number of batteries, the housing having a base and a side wall leading to an opening in the top of the housing, a releasable closure member for the opening provided with sealing means for sealing registration with the opening, the closure member being provided with a fluid venting aperture and an inlet aperture for cables and fluid, and the closure member being profiled internally thereof such as in use to assist the flow of fluid towards the venting aperture.

2. A container according to Claim 1 in which the housing is of hollow cylindrical form with a circular top defining the opening.

3. A container according to Claim 1 in which the housing is of rectilinear form with a rectilinear opening.

4. A container according to any one of the preceding claims in which the housing is provided with a mating formation for positive registration with the sealing means on the releasable closure member.

5. A container according to any one of the preceding claims in which the sealing means consists of an 0 ring seal, and a clamp is provided for positively securing the closure member to the housing.

6. A container according to any one of the preceding claims in which the closure member is dome-shaped or of concave form or of hollow pyramidal form and the fluid venting aperture is disposed at or substantially at or adjacent its topmost point with the inlet aperture being formed at a position spaced from the venting aperture.

7. A container according to any one of the preceding claims in which the inlet aperture has associated therewith a tube which, with the closure member in position sealing the opening of the housing, extends into the volume of the housing at a level below that of the venting aperture.

8. A container according to any one of the preceding claims in which the housing is provided internally thereof with a divider located at a distance from its base, the divider being adapted to support a platform affording a two-tier arrangement for the batteries with some batteries disposed on the base and others on the platform.

9. A container according to any one of the preceding claims in which the container is designed in accordance with the model as defined herein.

IO. A battery container for sub-surface installation substantially as herein described with reference to the drawings.

11. An installation for a bank of a batteries including a battery container according to any one of the preceding claims, a sub-surface well within which the container is adapted to be accommodated, a securable cap for the well, pipes for connection to the closure member of the container, and exit points provided in the well for the passage of the pipes therefrom to a surface location.

12. An installation according to Claim 11 in which the surface location is constituted by a cabinet into which in practice the pipes are led, with the final section of the pipe attached to the inlet aperture being disposed horizontally and the pipe attached to the fluid venting aperture being orientated vertically.

13. An installation according to Claim 12 in which the pipe attached to the fluid venting aperture is provided with a protective cover to prevent the ingress of extraneous material.

14. An installation for a bank of a batteries substantially as hereinbefore described with reference to the accompanying drawings.