GB2176565A

GB2176565A - Ice expansion buffer arrangement

Info

Publication number: GB2176565A
Application number: GB08613988A
Authority: GB
Inventors: Horace Ernest Ric Craig-Hallam
Original assignee: CRAIG HALLAM HORACE ERNEST RIC
Current assignee: CRAIG HALLAM HORACE ERNEST RIC
Priority date: 1985-06-15
Filing date: 1986-06-09
Publication date: 1986-12-31
Also published as: GB8613988D0; GB8515219D0

Abstract

A water pipe 1 contains a buffer comprising a resiliently compressible hollow pipe 2 made of polyesteracetal and held in position by means of end plugs 3 (providing water-tight seals) and radial arms 4. The buffer is arranged to absorb expansion pressure due to ice formation during freezing conditions. In the case of a tank or cistern the buffer may be a sphere 20 comprising a hollow resiliently flexible plastics globe or a solid "closed cell" foamed plastics ball with or without a resiliently flexible spherical outer case. <IMAGE>

Description

SPECIFICATION Ice expansion buffer arrangement This invention relates to an ice expansion buffer arrangement for use in pipes, tanks, cisterns and other water containers, situated inside and outside buildings.

Air temperatures in unheated buildings, even those which are well insulated will fall below freezing after only a few days of sustained freezing external temperatures.

As the temperature falls below freezing point, small ice crystals form on the surface of still water, a condition known as 'brash' ice.

Continued diminution of temperature causes the brash ice to congeal and to expand in volume. The volume of the ice is known to be about 8.3% greater than the volume of water from which it is formed. The first thin ice sheet which forms upon the water surface in supply pipes, storage cisterns and drainage traps inhibits the circulation of water and prevents warmer water reaching the surface.

The ice plug grows from the surface down expanding as the ice forms and imposing and increasing pressure on the inner face of the container which ruptures when its elastic limit is exceeded.

It is an object of this invention to mitigate the effects on the container of the expansion of the forming ice.

According to this invention there is provided a flexible buffer in a water container and occupying such a proportion of the volume or cross-sectional area of said water container that when the container contains water around said buffer, in the event of the water turning to ice, the expansion pressure of the newlyformed ice can be absorbed by the flexible buffer.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Fig. 1 and 2 are part-sectional diagrams of ice expansion buffer arrangements in respective first and second embodiments of the invention; and Figs. 3a to 3c are respectively side and end elevations and a plan view of an ice expansion buffer arrangement in a third embodiment of the invention.

Referring to Fig. 1 there is shown a pipe 1 of internal diameter A, in which an ice expansion buffer 2 is provided. In this embodiment the buffer is in the form of a hollow tube made of a material which is resiliently flexible over a predetermined temperature range and has low water absorption such as PEAT, polyesteracetal.

The wall thickness of the tube buffer is chosen to suit the water pressure to be experienced in the appliance, dependent on the head of water supplied in that location, and the diameter of the tube is chosen to allow a diminution in volume or cross-sectional area of the buffer which would be at least 8.3% and preferably at least 9% of the total volume or cross-sectional area of water in the relevant section of pipe. In many cases is may be sufficient if the buffer is capable of a diminution in volume or cross-sectional area of about 9%. It is expected that these restrictions on the dimensions of the buffer will in practice be achieved using a few standard sizes.

The length of the buffer used depends on the pipe (or appliance) being protected and the most severe conditions it is likely to be exposed to, so that the buffer could be measured and cut to length at the time of fitting.

The buffer shown in Fig. 1 is plugged at each end to make the hollow tube water-tight and at least one of the end plugs 3 is fitted with centering arms 4 whose length is such as to provide a snug fit within the bore of the pipe (or other appliance) which is being protected and thin enough to disturb flow as little as possible. In this case the arms have the effect of centering the buffer in the pipe, though this is not essential.

In an alternative form the buffer may comprise an elongate extrusion of resiliently flexible or compressible "closed-cell" foamed plastics material which could be used either on its own or within a resiliently flexible tube such as the tube 1. These forms of buffer would have the advantage of not requiring specially provided end plugs. Positioning arms similar to those shown in Fig. 1 could, however, be attached directly to the buffer and perform the same function as in the embodiment shown in Fig. 1.

It may also be appropriate in some circumstances to have a plurality of buffers distributed about the pipe system and possibly over the cross-sections of the pipes.

It will be appreciated that for any of the forms of buffer described above the flexibility of the buffer would allow it to follow bends in any pipes into which it is to be fitted.

In areas of low head pressure or as required by the Water Authority it may be necessary not to impede a specified rate of water flow in the rising main. This could be achieved by means of the embodiment shown in Fig. 2. A buffer similar to the one shown in Fig. 1 is fitted into a pipe 10 which is one size larger than the existing rising main, and terminated by suitable compression couplings 11 and 12.

Such a standard section of pipe could be substituted for a corresponding section of the rising main in vulnerable places.

When a tank or cistern is to be protected the surface area may be large compared to the total volume and in this case buffer shapes other than those described for the previous embodiments may be appropriate. Referring to Figs. 3a to 3c a buffer is in the shape of a sphere 20 and is protecting a cistern 21 having a ballcock 22. The sphere may com prise a hollow resiliently flexible plastics globe or a solid 'closed-cell' foamed plastics ball with or without a resiliently flexible spherical outer case.

The buffer would preferably be immersed to its maximum girth and anchored in that position, and the internal area of the globe at the water surface should be equal to at least 9% of the water surface of the cistern.

The shape of the buffer shown in Fig. 3 may be varied, for example, alternative shapes may comprise cylindrical or sausage shapes which would also make large expansion volumes available as water turned to ice.

A plurality of buffers may be distributed over the area of the water surface. Any shape used, however, must avoid disturbing the ballcock arrangement 22 within the cistern and must not cause blocking of the entrance pipe 24 or the exit pipe 25.

The anchoring of the buffer should be strong enough to withstand any water movement expected in the cistern so that the buffer cannot move sufficiently to obstruct free movement of the ballcock arrangement.

The anchor may take various forms and in the case where the cistern is made of a ferromagnetic material the anchor may be magnetic.

Claims

1. A flexible buffer in a water container and occupying such a proportion of the volume or cross-sectional area of said water container that when the container contains water around said buffer, in the event of the water turning to ice, the expansion pressure of the newly-formed ice can be absorbed by the flexible buffer.

2. A flexible buffer according to claim 1, wherein the buffer is capable of a diminution in volume of about 9%.

3. A flexible buffer according to claim 1 or claim 2, wherein the buffer is capable of a diminution in volume of at least 9%.

4. A flexible buffer according to any one of the preceding claims, wherein the buffer comprises a hollow member.

5. A flexible buffer according to claim 4, wherein the hollow member is filled with a resiliently compressible foamed synthetic plastics material.

6. A flexible buffer according to any one of the preceding claims wherein the buffer comprises a closed cell resiliently compressible foamed synthetic plastics material.

7. A flexible buffer according to any one of the preceding claims, wherein the buffer is made of a material which is resiliently flexible over the anticipated ambient temperature range and has low water absorption.

8. A flexible buffer according to claim 4, wherein said material is polyesteracetal.

9. A flexible buffer according to any one of the preceding claims, wherein the buffer is elongate and held in position in the water container by means extending transversely to the longitudinal axis of the buffer.

10. A flexible buffer according to claim 9, wherein the buffer comprises a hollow pipe, both ends of which are sealed in water-tight manner.

11. A flexible buffer according to any one of claims 1 to 8 and shaped as a ball, cylinder or sausage.

12. A flexible buffer according to any one of the preceding claims and provided with an anchor to hold the buffer in position in the water container.

13. A flexible buffer substantially as described herein with reference to Fig. 1 or Fig.

2 or Figs. 3(a) to 3(c) of the accompanying drawings.

14. A plumbing component incorporating a flexible buffer occupying such a proportion of the volume or cross-sectional area of said component that when the component contains water, in the event of the water turning to ice, the expansion pressure of the ice can be absorbed by the flexible buffer.

15. A plumbing component according to claim 14 and incorporating a flexible buffer according to any one of claims 2 to 13.

16. A plumbing component according to claim 14 or claim 15, incorporating a plurality of said buffers.

17. A plumbing component substantially as described herein with reference to Fig. 1 or Fig. 2 or Figs. 3(a) to 3(c) of the accompanying drawings.

18. A plumbing system including one or more plumbing components according to any one of claims 14 to 17.