GB2342418A - Inflatable bag for blocking flow in a slit drainage pipe - Google Patents

Abstract

The bag, in collapsed form, is insertable through the narrow slit in the upper part of the drainage pipe, the bag having an opening in an upper region thereof through which a fluid such as water can be forced as from a hosepipe, to inflate that part of the bag within the cross-section of the pipe and act as a bung and temporarily prevent the passage of liquid along the pipe. A lower edge region of the bag contains a rigid rod 28 which may be encapsulated or embedded therein or otherwise attached thereto, and insertion of the bag involves pushing one corner of the rod-containing end of the bag into the slit whilst gripping the other end of the rod through the bag and feeding the rod-containing end of the bag diagonally into the pipe until the rod and sufficient of the bag has been passed through the slit into the interior of the pipe. Such bags are used e.g. to prevent spread of liquid chemical after a spillage. After use, the bag can be punctured for removal.

Description

Title : Improvements in and relating to drainage bunas Field of invention This invention concerns bungs for drainage pipes, particularly surface water drainage pipes of the type having an elongate slit opening in their wall along their length through which surface water can drain into the pipe.

Background to the invention It has become conventional to drain water from gutters along the edges of roads by laying such pipes end to end and joined to form a continuous length, along the length of the gutter, parallel to the road with the slit in the wall through which water can drain exposed to the gutter, so that surface water collecting in the gutter can pass into the pipe through the slot and from thence into the surface water drainage system in the subsoil below.

It is a problem with such drainage systems that if there is a spillage of a liquid chemical this can just as easily enter the collecting pipe through the slit, as can surface water, and if steps are not taken to prevent the passage of the unwanted liquid through the pipe, this can find its way into the surface water drainage system with possible hazardous results and/or contamination.

The main difficulty with such drainage pipes is that access to the main cross-section of the pipe is not available. There are no grids and large apertures through which water and other liquids flow and which can be readily covered over in the event of such a spillage. The length of the slit is as long as the road and consequently to try and cover or block the slit is also a difficult task, particularly if time is limited, as is often the case where a chemical spillage has occurred, and it is necessary to prevent as much as possible of the spillage from entering the drainage system.

It is an object of the present invention to provide a device for use with such pipe drainage systems so as to reduce the contamination which a chemical or other liquid spillage can create.

Summary of the invention According to the present invention, a collapsible bag is provided adapted to be inserted through the narrow slit of a drainage pipe as aforesaid whilst in its flattened and collapsed condition with an opening in an upper region thereof through which a fluid such as water can be forced as from a hosepipe, to inflate the bag particularly that part located within the cross-section of the pipe, so as to cause the bag to swell and occupy the whole of the cross-section of the pipe and act as a bung and temporarily prevent the passage of liquid along the pipe.

According to a preferred feature of the invention a lower edge region of the bag contains a rigid rod which may be encapsulated or embedded therein or otherwise attached thereto, the crosssection of the rod being smaller than the width of the slit in the pipe into which the bag is to be inserted, and insertion of the bag involves pushing one corner of the rod containing end of the bag into the slit whilst gripping the other end of the rod through the bag and feeding the rod containing end of the bag diagonally into the pipe until the rod and therefore at least part of the bag has been passed through the slit into the interior of the pipe.

Since the rod is attached to the bag, the latter follows the rod into the pipe and it is then only necessary to start filling the bag with water or other liquid material, to cause that part of the bag outside the pipe to be drawn through the slit into the pipe until that part of the bag which is in the pipe and is full of water or other liquid, fully occupies the cross-section of the pipe. At this stage there is no tendency for a further drawing of the bag into the pipe, but that section of the bag which lies above the slit in the pipe will continue to fill with water and overlay the pipe on opposite sides of the slit.

Preferably the bag is formed from thin sheet flexible material such as sheet plastics material, and this not only permits the bag to be drawn down through the slit in the pipe as the lower section of the bag begins to fill with water, thereby pulling the upper regions of the bag through the slit, but once the bag has fully occupied the cross-section of the pipe, the flexible nature of the sheet material is such that the water filled region of the bag above the slit will tend to conform to the shape of the pipe, or the immediate surroundings of the slit where the pipe has been embedded in a road surface such as a tarmacadam or concrete surface, so as to form an additional seal around the slit, to prevent the ingress of any liquid material for example from a spillage of a liquid chemical on the site, from passing into the slit around the sides of the bag, and thereby leave traces of the chemical spillage within the drainage pipe after the bag has been removed.

A method of containing a spillage of a liquid chemical therefore comprises the steps of inserting a bag as aforesaid into a region of the pipe downstream from the spillage and rapidly filling the bag with water or other liquid material by for example using a hosepipe, so that the bag completely fills the cross-section of the pipe, thereby preventing the flow of any spilled liquid chemical downstream of the bung so formed.

The bung can be removed quite simply by puncturing the bag after the spilled chemical has been neutralised or diluted or collected or otherwise disposed of. The liquid filling the bag simply flows away downstream of the drainage pipe, into the drainage system connected thereto.

The bag is most simply formed from an endless sleeve of sheet plastics material flattened so as to form a generally rectangular envelope having open ends, seam welding one end so as to close it and also form a pocket for an elongate rod which is to extend thereacross, and at the other end, arranging for two seam welds to extend from the two opposite folds incompletely across that end so as to leave an opening through which a hosepipe or the like can be inserted to fill the bag with water or other liquid.

Where the rod is not as long as the envelope is wide, the rod is conveniently located centrally of the envelope width, and opposite corners of the end of the envelope containing the rod are cut away at 45 degrees, and seam welded along the 45 degree cuts.

According to another preferred feature of the invention, the other end of the bag is similarly cut away so as to define two 45 degree corners instead of sharp rectangular corners, and seam welds are formed along the length of the two 45 degree corners, which merge with two further seam welds which extend from opposite sides of the opening.

The size of the bag is chosen to suit the diameter of the pipe which is to be blocked by the bag. In a typical arrangement, the bag is approximately lm wide from one folded edge to the other, and is approximately 1.2m long from the end containing the rod to the end containing the opening through which it is to be filled. Such a bag may be used to block a drainage pipe of the type described, which has an internal diameter of approximately 24 inches, that is approximately 600mm.

The invention is of particular application in conjunction with motorway and other highway drainage systems which incorporate such drainage pipes along the length of the roadway, or on industrial sites and on commercial premises where yards and other areas including roadways are drained in a similar way.

It is a feature of the invention that inflatable bags as aforesaid may be carried by emergency vehicles such as fire engines and fire tenders, police cars and the like, which regularly attend highway accidents, so that in the event of a chemical spillage, a bung can be inserted into the drainage system as quickly as possible after an accident has occurred so as to inhibit passage of the spillage into the drainage system.

A preferred material is polyethylene preferably with an acetate additive such as EVA so as to reduce the working temperature of the material and reduce creasing and make the sheet material more flexible to make insertion of the bag into the pipe easier and more reliable.

The rigid rod may be formed from wood or plastics material such as polythene.

The invention thus provides a method of preventing widespread contamination of a drainage system, supplied by a slit pipe which drains a site on which a liquid chemical spillage has occurred, comprising the steps of: (1) inserting an inflatable bag into a region of the slit pipe downstream from the spillage, and (2) rapidly filling the bag with water or other fluid material, so that the bag completely fills the cross-section of the pipe, thereby preventing the flow of any spillage liquid along the drainage pipe downstream of the bung so formed.

It is a feature of the invention that the bung can be removed after the liquid chemical spillage has been diluted, collected or otherwise disposed of, by puncturing the bag whilst preventing the bag from fully entering the pipe through the slit, so that the water or other fluid contained therein flows away into the drainage system and the now empty bag is thereafter retrieved by pulling it back through the slit. Where the chemical spilled may attack the bag material a plurality of bags as aforesaid may be inserted into the slit drainage pipe draining the site, so as to form a series of separate bungs downstream of the spillage, so that if the bag material is chemically reactive with the spilled liquid and will be destroyed by chemical attack, and when so damaged will cease to block the pipe, the next bag in the series is available to prevent further downstream flow of the spilled liquid further along the pipe.

The liquid for filling at least some of the bags may be chosen for its chemically reactive properties when combined with the spilled chemical so as to neutralise the latter and/or render it less harmful. Alternatively a particulate or liquid reagent may be added to the bag before or during filling to mix with the liquid which is being used to fill the bag, to form a compound or mixture which will likewise react with the spilled chemical.

The selected filling material or added particulate or liquid reagent may be chosen to reduce the tendency for the spilled chemical material to attack the bag material. This selected material or additive may be employed in the first of the bags in the said series.

A reagent material in particulate or liquid form may be located in the bag either during manufacture or prior to filling.

The invention will now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a cross-section through an end of a drainage pipe of the type described; Figure 2 is a plan view of a bag in a deflated condition incorporating the invention; and Figure 3 is a cross-section through the pipe of Figure 1 after the bag has been inserted into the pipe and filled with water.

Detailed description of drawings In Figure 1 a drainage pipe 10 is shown with a drainage slit or slot 12 in its upper region. The slot 12 extends along the whole length of the pipe and which may be continuous or comprised of pipes joined end to end along the length of the highway gutter in which water can collect, so that water can pass through the slot 12 and into the interior of the pipe 10. By laying the pipes with a slight fall, the water in the pipe will then drain away to the lowest point in the pipe system from which it is collected, typically into a sump.

It will be seen that any liquid can pass through the slot 12 and therefore if there is a chemical spillage on the highway or in a yard or other area drained by the pipe, it will also enter the pipe, and therefore the drainage system.

It is an object of the present invention to restrict the passage of such unwanted chemical spillage into the drainage system.

The invention provides an inflatable bag 14 shown in Figure 2 formed from a continuous sleeve of sheet plastics material such as polyethylene with an appropriate acetate additive to make the material flexible, crease resistant and capable of operating over a useful range of temperatures. Each bag is formed by cutting the four corners of the generally rectangular envelope which is formed when the sleeve is flattened as shown in Figure 2, and each of the corners is then seam welded by seam welds 16 and 18 at the lower end, and 20 and 22 at the upper end, of the bag.

In addition to the two 45 seam welds 16 and 18 at the lower end of the bag, two further seam welds 24 and 26 extend across the lower end of the bag between the two corner welds 16 and 18, the two seam welds 24 and 26 being parallel and spaced apart so as to provide a narrow sleeve within which a rod designated 28 can be contained. The welds 16 and 18 retain the rod within the sleeve formed by the two welds 24 and 26.

Centrally of the opposite end of the bag 14 is formed an opening 30 formed by two semi-circular cuts through an otherwise seam welded end. The seam weld 32 which extends between the two corner welds 20 and 22 is thus interrupted by virtue of the cuts at either side of the opening 30 and if the upper end of the bag is crushed so that the material forming the wall of the opening 30, separate, a generally circular opening is revealed into which the nozzle of a fireman's hose or the like can be pushed for filling the bag with water.

In practice, the bag is inserted into the hollow interior 34 of the pipe 10 shown in Figure 1 by poking one end (for example the left hand end as shown in Figure 2) of the rod 28 (albeit within the sheet plastics bag) into the slot 12 in the general direction of the arrow 36 in Figure 1, and continually pushing the rod 28 in that general sense into the pipe through the slot until most of the rod is now inside the pipe. Water introduced into the upper part of the bag will flow into that part of the bag below the slot which will begin to fill with water and become heavier, causing the unfilled bag above the slot to be pulled through the slot under gravity.

The process continues until the whole of the section of the pipe has become occupied by the water filled bag as shown in Figure 3. Here the rod 28 can be seen at the bottom of the pipe. The remainder of the bag 38 above the slot cannot be pulled into the pipe, but remains above the slot 12.

There is no need to discontinue filling the bag with water since there is an advantage in continuing to fill the region 38 of the bag above the slot. By doing so, a seal is formed between the underside of the bag region 38 and the slot and the region 38 will in fact splay over in the way shown in Figure 3 until its underside overlays the surface of the highway or the surface of the pipe whichever is exposed, on either side of the slot.

As shown in Figure 3, highway material 40 and 42 is shown on either side of the slot, inclined down towards the slot, so as to form a water collection region such as a gutter or gulley, and the bag region 38 has settled so as to fully seal against the surfaces of the regions 40 and 42 which further seals the pipe 10 from the ingress of the spillage which can otherwise occur between the surface of the bag and the slot. Should this occur, liquid can become trapped between the outside surface of the bag and the inside surface of the pipe 10 and remain there to become exposed to the drainage pipe once the bung formed by the bag has been removed as by bursting the bag and allowing the water to flow away.

It will be appreciated that once the bag has been punctured in this way, and the water has flowed away out of the bag, the bag can be retrieved by pulling it back through the slot 12. The bag can then be discarded.

The water occupying the interior of the bag in the region which occupies the cross-section of the pipe is denoted by reference numeral 44, and by reference numeral 46 in the case of the region of the bag overlying the upper region of the slot and sealing the slot against ingress of liquid from the road surface 40,42.

Depending on the nature of the chemical spillage, the bung formed by the bag may only have a limited life of some few minutes. In this event, in accordance with the invention, a second or more bags may be inserted downstream of the first, so as to provide a number of barriers, each of which has to be attacked by the chemical spillage before the spillage can finally enter the drainage system. In accordance with the invention, a sufficient number of bags are located. into the drainage pipe and inflated with water or other liquid, as to provide a sufficient length of time to enable the emergency services to deal with a spillage that has been contained to the region of the pipe.

Claims (20)

1. CLAIMS 1. A method of blocking a drainage pipe having an elongate drainage slit extending along the length thereof comprising the steps of inserting a collapsible bag through the elongate slit whilst in a flattened condition, so that an opening in an upper region of the bag remains outside the pipe, and inflating the bag by pouring or otherwise forcing a liquid such as water into the bag through the said opening, so as to cause the bag to swell and occupy the whole of the cross-section of the pipe and act as a bung thereby to prevent the passage of liquid along the pipe.
2. 2. A method as claimed in claim 1, wherein a lower edge region of the bag contains a rigid rod to facilitate the introduction of the bag into the pipe through the slit.
3. 3. A method as claimed in claim 2, wherein the insertion of the bag into the pipe involves pushing one corner of the end of the bag containing the rod into the slit whilst gripping the rod through the other corner of the same end of the bag and feeding the rod-containing end of the bag down into the pipe until the rod and therefore at least part of the rod-containing end of the bag has been passed through the slit into the interior of the pipe.
4. 4. A method as claimed in claim 3, further comprising the step of filling the bag with water and permitting part of the remainder of the bag which has not entered the slit to be drawn down through the slit into the interior of the pipe under the weight of the water collecting in the lower part of the bag, until the water filled part of the bag which has been drawn into the pipe fully occupies the cross-section of the pipe.
5. 5. A method as claimed in claim 4, comprising the further step of continuing to pour or otherwise force water into the bag so that that section of the bag which lies above the slit in the pipe also fills with water and overlays the pipe on opposite sides of the slit.
6. 6. A bag adapted for use in the method of any of claims 2 to 5, which is formed from thin flexible sheet material such as sheet plastics material, and which has a rigid rod embedded or encapsulated in, or otherwise attached to the sheet material across the closed end of the bag, and which not only permits the flattened bag to be pushed down through the slit in the pipe, but as the lower section of the bag fills with liquid and fully occupies the internal cross-section of the pipe, the flexible nature of the sheet material is such that with continued filling of the bag with liquid above the level of the pipe, the liquid filled region of the bag above the slit will tend to spread out and form a seal.
7. 7. A bag as claimed in claim 6, formed from an endless sleeve of sheet plastics material flattened so as to form a generally rectangular envelope having open ends which are seam welded so as to form at one end a pocket for the elongate rod which is to extend thereacross and at the other end, an opening between a pair of seam welds extending from opposite folds to the opening, through which a hosepipe or nozzle or the like can be inserted to fill the bag with water.
8. 8. A bag as claimed in claim 7, wherein the rod is not as long as the envelope is wide and the rod is located centrally of the envelope width and opposite corners of the end of the envelope containing the rod are cut away at 45 degrees, and seam welded along the 45 degree cuts.
9. 9. A bag as claimed in claim 8, wherein the other end of the bag is similarly cut away so as also to define two 45 degree corners and seam welds are formed along the length of the two 45 degree corners, and the 45 degree seam welds merge with two further seam welds which extend across the end containing the opening between the opening and the 45 degree corner welds.
10. 10. A bag as claimed in any of claims 6 to 9, wherein the bag is formed from polyethylene.
11. 11. A bag as claimed in claim 10, wherein the polyethylene includes an acetate additive such as EVA so as to reduce the working temperature of the material, reduce creasing, and make the sheet material more flexible to further facilitate its insertion into the pipe.
12. 12. A bag as claimed in any of claims 6 to 11, wherein the rigid rod is formed from wood or plastics material such as polythene.
13. 13. A method of preventing widespread contamination of a drainage system supplied by a slit pipe which drains a site on which a liquid chemical spillage has occurred, comprising the steps of: (1) inserting an inflatable bag into a region of the slit pipe downstream from the spillage; and (2) rapidly filling the bag with water or other fluid material, so that the bag completely fills the cross-section of the pipe, thereby preventing the flow of any spillage liquid along the drainage pipe downstream of the bung so formed.
14. 14. A method as claimed in claim 13, wherein the bung is removed after the liquid chemical spillage has been diluted, collected or otherwise disposed of, by puncturing the bag whilst preventing the bag from fully entering the pipe through the slit, so that the water of other fluid contained therein flows away into the drainage system and the now empty bag is thereafter retrieved by pulling it back through the slit.
15. 15. A method as claimed in claim 13, wherein a plurality of bags of the type claimed in any of claims 6 to 12 are inserted into the slit drainage pipe draining the site, so as to form a series of separate bungs downstream of the spillage, so that if the bag material is chemically reactive with the spilled liquid and will be destroyed by chemical attack, and when so damaged will cease to block the pipe, the next bag in the series is available to prevent further downstream flow of the spilled liquid further along the pipe.
16. 16. A method of containing a liquid chemical spillage as claimed in claim 15, wherein a liquid is selected for filling at least some of the bags which will react with the spilled chemical to neutralise it and render it less harmful, or a particulate or liquid reagent is added to the bag before or during filling to mix with the liquid which is being used to fill the bag, to form a compound or mixture which will likewise react with the spilled chemical.
17. 17. A method as claimed in claim 16, wherein the selected filling material or added particulate or liquid reagent is chosen to reduce the tendency for the spilled chemical material to attack the bag material, and this selected material or additive is employed in at least the first of the bags in the said series.
18. 18. A bag as claimed in any of claims 6 to 12, wherein a reagent material in particulate or liquid form is located in the bag either during manufacture or prior to filling.
19. 19. A bag for use in containing a liquid spillage on a site drained by a slit drainage pipe, constructed and arranged substantially as herein described, with reference to and as illustrated in the accompanying drawings.
20. 20. A method of preventing a liquid spillage from contaminating a drainage system downstream of a slit drainage pipe draining the site of the spillage, substantially as herein described, or as illustrated in, the accompanying drawings.