GB2080914A - Sewer pipe stopper - Google Patents

Abstract

The device provides a means for connecting a temporary by-pass pipe to a sewage pipe to enable the normal gravity flow of sewage to be maintained whilst work is being performed on the sewage pipe-line. The use of pumps is thereby avoided. The device consists of a large diameter drainage tube (1) and an encircling inflatable tube (13) for sealing the drainage tube to a sewage pipe (2). A by-pass pipe is connected in use to the free end (1') of the drainage tube. Sewage flow is controlled by a gate valve (16) which in the open position leaves the bore of drainage tube (1) unobstructed. The by-pass pipe is conveniently led through a section of pipeline on which work, such as relaying of the pipeline, is being performed. <IMAGE>

Description

SPECIFICATION Sewer pipe stopper This invention relates to a sewer pipe stopper, and to methods of repairing and relaying sewers.

A well known form of stopper for a sewer pipe comprises a pair of circular metal plates between which is sandwiched a rubber disc, and a screw is arranged to draw the plates together so that the radially outer edge of the rubber disc is pressed into sealing engagement with the inner wall of a pipe. The resilience of the disc enables the stopper to be used with pipes of slightly differing diameters, but a large number of such stoppers of different sizes is needed to cover a useful range of pipe sizes.

Stoppers are known which are provided with a small-diameter fluid passage extending axially through the stopper to enable pressure testing of pipes to be performed, however the fluid passage is not intended or capable of being used to pass sewage.

The present invention stems from a realisation that it would be a considerable advantage to be able to maintain the flow of sewage in a sewer pipe line without the use of pumps whilst a length of the pipe line is being repaired, or whilst the existing pipes are being replaced by larger diameter ones. If the flow of sewage is stopped completely by a conventional stopper and no pumps are employed upstream of the stopper, then arresting the flow can lead to blockages which can be difficult to clear when the stopper is removed. Even when pumps are employed they often become blocked.

According to one aspect of the invention a sewer pipe stopper comprises a rigid, substantially fluid-tight body, an encircling inflatable sealing assembly for sealing the body to the inner wall of a sewage pipe, circumferentially spaced clamping means carried by the body and adapted to be engageable with the sewage pipe to prevent movement of the body relative to the pipe under pipeline fluid pressure forces, the body comprising a through-flow drainage passage of substantial diameter terminating in a by-pass connection, and valve means operative in a closed condition to close the drainage passage and in an open condition substantially to open the drainage passage to provide a substantially unobstructed flow path for sewage to the by-pass connection.

It will be appreciated that the diameter of the through-passage will be substantially greater than the pressure-test passages previously provided in some stoppers.

Preferably the diameter of the passage is at least 4 ins (100 mm) in order to provide an adequate flow of sewage under most conditions.

A particularly convenient diameter of the passage is 6 ins (150 mm), but a larger diameter may be employed for particularly large sewage pipes.

The valve means may be of any suitable kind, but preferably it comprises a gate valve.

Although the stopper will usually be intended for use with pipes of circular cross-section, the stopper may be adapted for use with pipes of non round cross-section. For'example, a'square- section culvert may be stopped by a stopper provided with a body of similar, but reduced, outline to that of the culvert.

The inflatable sealing assembly preferably comprise's a tube,#but if desired it might comprise a series of independently inflatable cushions located adjacent to one another.

When a tube is employed it may be a continuous tube or it may comprise a length of tubing with sealed ends which is wrapped around the body.

An advantage of using a length of tubing is that the effective size of the stopper may be varied by altering the amount of said length that is wrapped around the tube, or simply the amount by which the wrapped tube is inflated.

The body is preferably provided with an encircling recess in which the sealing member is seated to locate it in position.

A particularly lightweight construction may be achieved when the body comprises a plate for arrangement in a plane substantially normal to the axis of the pipe, and a depending rim which is shaped to define at least the base of said recess.

The rim is conveniently of L-shape in transverse cross-section, and the free end of one limb of the L is connected to the plate to extend at substantially 900 thereto, with the other limb of the L extending substantially parallel to the plate, so that the first limb defines one side of the recess, the radially outer part of the plate defines the opposite side of the recess, and the other limb defines the base of the recess.

The plate is preferably reinforced against bending by circumferentially spaced, radially extending webs which conveniently comprise elongate plates each having one of its longer sides welded to or otherwise secured to one face of the main plate, the elongate plates extending in planes normal to the'plane of the main plate.

Conveniently, the radially outer edge of each elongate plate is secured to said one limb of the rim.

The body preferably comprises a central hub provided with the fluid passage and valve means, and a plurality of detachable annular body discs of different sizes is provided for selective connection to the hub. Each of the body discs preferably comprises an annular main plate with radially extending webs as previously described.

Mechanism for operating the valve means, mechanism for operating the clamping means and access to inflation means for the seal are conveniently provided on the side of the device provided with the by-pass connection to enable the operator to make all adjustments from that side of the device.

According to a second aspect of the invention a method of performing work on a length of sewage pipeline comprises inserting into the pipeline at a location upstream of said length a stopper in accordance with the first aspect of the invention, arranging a temporary by-pass pipe to extend from the by-pass connection of the stopper to a location of the pipe-line downstream of said length and substantially carrying out said work whilst the flow is by-passed through the by-pass pipe.

The work may comprise the laying of a branch pipe to the pipeline or any kind of work which would be facilitated by diverting the normal flow.

It will be understood that the flow will usually need to be stopped by closing the valve means of the stopper during laying out and subsequent removal of the by-pass pipe, but this need not take long, so that the flow can be maintained for most of the time.

When the work comprises replacement of a length of pipe, usually it will be possible to lay the by-pass pipe through the length of pipe that is to be replaced, and the use of a flexible by-pass pipe facilitates this method.

When a new, larger diameter sewer is being laid along the line of an old sewer, the stopper and by-pass pipe enable the old pipes to be replaced one by one by the new pipes, with gravity flow being maintained for most of the time between the end of the old pipeline and the beginning of the new through the by-pass pipe.

A pair of stoppers is preferably used for this, one stopper being inserted into the pipeline upstream of the next section to be replaced, conveniently at an upstream manhole, and its valve is closed whilst the second stopper is transferred from the downstream to the upstream end of said next section, and the by-pass pipe is relaid from the second stopper to extend through said next section to the end of the new line.,The first stopper may then be opened, and said next section broken up and removed.

The invention will now be further described, by way of example only, with reference to the accompanying drawings in which:~ Figure 1 is a longitudinal cross-section of a stopper in accordance with the invention assembled in the end of a sewer pipe of relatively small diameter; Figure 2 is an end view of the stopper of Figure 1 looking from the left in Figure 1; Figure 3 is a view similar to Figure 1 but showing the use of an auxiliary conventional, stopper in conjunction with the stopper of Figure 1 for pressure testing purposes; Figure 4 is a longitudinal cross-section similar to Figure 1 but showing the stopper of Figure 1 adapted to fit a larger diameter pipe by the attachment of a disc assembly, the radially outer part of a larger disc assembly also being shown;; Figure 5 is a section on the line 5-5 of Figure 4, but with the clamping screws omitted; Figure 6 is a view similar to Figure 1 of a modified stopper in accordance with the invention; Figure 7 is a schematic plan view of a manhole with various pipe connections and two stoppers being used to by-pass flow through the manhole; and Figure 8 is a schematic vertical cross-section along a pipeline during re-laying with larger diameter pipes.

Referring to Figures 1 and 2, the stopper comprises a drainage tube 1 of intemal diameter 150 mm (6 ins) coaxial with pipe end 2 of internal diameter 300 mm (12 ins) and having welded thereto axially spaced abutment rings 3 and 4 to which respective annular plate assemblies 5 and 6 are secured by respective series of circumferentially spaced screws 7 passing through holes in the assemblies 5,6 and threadedly engaging the rings 3, 4. As shown in Figure 2, plate assembly 5 consists of two semi-circular plate segments 5 for assembly purposes.

The left-hand end 1' of the tube 1 provides a by-pass connection to which a by-pass pipe is connected in use.

An annular radially outwardly facing recess 8 is defined between the plates 5, 6, between the rings 3 and 4 and by the radially outer surface 9 of the tube 1, and an annular rubber tube 13, which may conveniently be a wheel-barrow inner-tube, is seated in the recess 9 with a valved inflation tube 10 extending through aligned holes 11 and 12 in ring 3 and plate 5 respectively to an accessible position. Tube 13 has been inflated to a predetermined pressure to seal against the inner wall 14 of pipe end 2. As shown in Figure 1, the rings 3 and 4 are provided with rounded comers 15 to prevent damage to the tube 13.

Tube 1 carries adjacent to its left hand end 1', that end which in use is accessible to the operator, a gate valve assembly 16 which comprises a guide 17 welded to the tube 1 and a vertically slidable gate 18 in the form of a flat metal plate of oblong rectangular outline apart from its lower end 18' which is of semi-circular outline. Guide 17 is formed from a flat backing plate 20 provided with a substantially semi-circular cut-out at its lower end to fit the outer wall of tube 1, and two opposed guide slots 19 are defined by elongate edging strips 21 and by respective retaining strips 22, all welded together. Gate 18 extends through a semi-circular slot 23 in the pipe and is shown in its closed position in Figures 1 and 2 locked by a retaining pin' 24 which is inserted into aligned holes in the gate 18 and backing plate 20. A loop handle 25 with forwardly cranked arms 26 is attached to the gate 18 to enable it to be raised ,substantially clear of slot 23 where it may be retained by reinserting pin 24 through' afurther hole 27 in plate 20, as shown in Figure 3. An angle piece 28 welded to the top of plate 20.

It will be appreciated that when the gate 18 is fully raised the bore of tube 1 is substantially unobstructed and thereby provides free passage to sewage.

Figure 3 shows that a conventional pipe stopper 29 may be inserted into tube 1, inwardly of slot 23 to seal tubeI:#against high pressures when it is desired to pressure test the pipe 1. The conventional stopper comprises a rubber disc 30 compressed between metal plates 31 and 32 and provided with an t;w33 which communicates with an inlet port, whose position is indicated at 34. To pressure test pipe 2, a source of pressure is connected to tube 33.

Figures 4 and 5 shows an assembly for use with a sewer pipe of internal diameter approximately 24 ins which has been produced from that of Figure 1 by removal of plate assembly 5 and tube 13, and by replacing plate 6 by an annular disc assembly. Thus the adapted stopper uses the existing tube 1 and rings 3 and 4 as the-hub of the new body. Disc assembly 35 comprises a flat annular disc 36 with a depending rim 37 of L ~ shape in transverse cross-section. A first limb 38 of the rim extends parallel to disc 36, and a second limb 39 extends perpendicularly to disc 36 to define the base of an annular recess 37' of which the sidewalls are defined by limb 38 and the radially outer margin 39 of disc 36.As shown in Figure 5, a length of rubber tubing 40 with sealed ends 41 and 42 is wrapped twice around the disc assembly 35 and inflated by means of tube 10' extending through a hole 11' in limb 39.

Plate 36 is reinforced against bending by circumferentially equally spaced, radially extending webs in the form of elongate plates 43 which are welded along one longitudinal edge to plate 36 and at one end to limb 39. At their radially inner ends 44 the plates 43 abut the abutment rings 3 and 4.

Six circumferentially spaced lugs 45 in the form of square plates are welded to the rim 37 to support respective radially directed clamping screws 46 for clamping the stopper to the inner wall of the pipe thereby to relieve the tube 40 from sideways forces. Each screw 46 is provided with a hexagonal head 47 at its inner end and with a rotatable button head 48 at its outer end.

Further lugs 45' in the form of threaded bosses are shown in Figure 5 welded to the tube 1 to enable the tube 1 to be clamped to a pipe of small diameter by suitable clamping screws when the device is assembled as shown in Figure 1.

In the upper part of Figure 4 is shown part of a further disc assembly 35' of larger diameter than that of the assembly 35 which can be secured to" the tube 1 by bolts 7 for use-with pipes of approximately 36 ins diameter. It will be appreciated that several such disc assemblies may be provided for use with the same-hub assembly 1,3, 4, but since each disc assembly is capable of being used with a wider range of pipes than a conventional stopper, fewer devices will be required than with conventional stoppers.

In Figure 6 corresponding reference numerals have been applied to parts corresponding to those of Figure 1. In this modification of the Figure 1 construction a relatively thin-walled pneumatic tube 13 is employed, and the radially outer surface of the tube is protected against abrasion with the sewer pipe by a flexible skirt 13' of thick rubber which has an inturned waist 49 sealing clamped between plate 6 and abutment ring 4. The sealing of gate 18 to tube 1 is improved by the provision of a rectangular rubber sheet 50 of which the upstream end is secured by suitable means to the inner wall of tube 1 8, the sheet extending circumferentially through the upper half-circle of the tube 1. Several holes 27 are provided to enable the gate 18 to be held at different heights for flow-control purposes.

Figure 7 shows the use of a pair of stoppers 51 of the kind shown in Figure 1 being used to bypass a man-hole 52 during the laying of a third man-hole inlet pipe-line 53, and a larger diameter outlet pipe-line 54. As originally constructed, the manhole 52 provided a fluid connection from inlet pipes 55 and 56 to an outlet pipe 57 of similar diameter. In order to accommodate the flow from the new inlet pipe 57 a larger diameter outlet-pipe 54 is required. New pipe-line 54 has been laid to the position shown in full outline by the method to be described hereafter with reference to Figure 8.

Stoppers 51 are then inserted from the manhole opening 58 into the pipes 55 and 56, the clamping screws are tightened to secure the stoppers in position, and sealing tubes 13 are inflated. The gate valve assemblies 16 are then closed to enable 6" diameter rubber by-pass hoses 59 to be laid through the manhole opening 58, the remaining portion 57 of the old outlet pipe, and into the end of the new pipe-line 54. The hoses 59 are firmly secured over the tube ends 1', and the gate valve assemblies 16 are then opened to allow sewage to flow under gravity forces through hoses 59 into new pipe line 54. It is then possible for the necessary work to be carried out on the manhole 52 to introduce the new pipe line 53, and the remainder of the old outlet pipe 57 can be exposed, broken up and removed from around the hoses 59.All preparatory work for installing the last section of new outlet pipe can be made before the valve assemblies 16 need be closed to allow removal of hoses 57 for the actual installation.

Thus, flow of sewage is maintained without the use of pumps for the majority of the time that the work is being carried out, and there is little chance of sewage accumulating upstream of the manhole to cause blockages or other problems.

It will be appreciated that a similar procedure could be adopted if the manhole 52 were merely being adapted to receive pipe 53, without any alteration being made to the pipe 57.

With reference to Figure 8, this shows an existing sewage pipe-line 60 being replaced by a larger-diameter pipe-line 61. A first stopper 62 has been secured in position at a manhole 63 upstream of the section being relaid, to enable the flow to be cut-off for brief periods. Excavation is carried out to expose the next length 64, indicated in dotted outline, of existing pipe to be replaced.

At this stage a second stopper 65 is in the downstream end of pipe length 64, with flow passing therethrough. Stopper 62 is then closed briefly to allow a hole to be made at 66 in pipe 64.

Stopper 65 is then extracted from its present position and inserted through the hole at 66 where it is secured in position, and a by-pass hose 67 is laid from the by-pass connection 1' of stopper 65 through old pipe 64 into the end of pipe-line 61. Stopper 62 is then opened to allow flow to resume, the flow passing from line 60 to line 61 through hose 67. Pipe 64 may then be broken up, the pieces removed, and the trench bottom prepared to receive a new length 68 of pipe, all whilst the flow continues through hose 67.

When all is ready for installation of the new length 68 stopper 62 is closed, hose 67 rolled up, and the new length 68 brought into place. The hose 67 is then led into the new length 68, and stopper 62 opened to allow resumption of flow.

Excavation is then made again and the sequence of operations described is repeated to replace further lengths until the manhole 63 is reached.

The stopper 62 is then, of course, removed to the preceding upstream manhole, not shown, and the section of pipeline between the two manholes is replaced in the same manner.

Since sewage flow is interrupted only for brief periods no substantial build-up of sewage occurs and, again, no pumps will usually be required;

Claims (17)

1. A sewer pipe stopper comprising a rigid, substantially fluid-tight body, an encircling inflatable sealing assembly for sealing the body to the inner wall of a sewage pipe, circumforentially spaced clamping means carried by the body and adapted to be engageable with the sewage pipe to prevent movement of the body relative to the pipe under pipeline fluid pressure forces, the body comprising a through-flow drainage passage of substantial diameter terminating in a by-pass connection, and valve means operative in a closed condition substantially to close the drainage passage and in an open condition substantially to open the drainage passage to provide a substantially unobstructed flow path for sewage to the bypass connection.

2. A pipe stopper as claimed in claim I in which the diameter of the passage is at least 100-mm.

3. A pipe stopper as claimed in claim 1 in which said diameter is substantially 150 mm.

4. A pipe stopper as claimed in any of the preceding claims in which the valve means is a gate valve. ss ..

5. A pipe stopper as claimed in any of the preceding claims in which the inflatable sealing member comprises a tube.

6. A pipe stopper as claimed in Claim Sin which the tube is a continuous tube.

7. A pipe stopper as claimed in Claim 5 in which the tube comprises a length of tubing with sealed ends which is wrapped around the body.

8. A pipe stopper as claimed in any of the preceding claims in which the body is provided with an encircling'recess in which the sealing member is seated to locate it in position: ~

9. A pipe stopper as'claimed in Claim 8 in which the body'comprises a plate for arrangement in a plane extending substantially normal to the axis of the pipe, and a depending rim which is shaped to define at least the base of said recess.

10. A pipe stopper as claimed in Claim 9 in which the plate is reinforced against bending by circumferentially spaced, radially extending webs.

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11. A sewer pipe stoppersubstantially as described with reference to Figures 1 and 2 of the accompanying drawings. "' - -

12. A sewer pipe stopper substantially as' claimed in claim 11 Sand adapted to fit larger diameter pipes substantially as described with reference to Figures 4 and 5 of the accompanying drawings.

13. sewer pipe stopper as claimed in claim 11 but modified substantially as described with reference to Figure 6 of the accompanying drawings. ' r

14. A method of performing work on a length of sewage pipeline comprising inserting into the pipeline at a location upstream of said lerigth a stopper in accordance with any of the'preceding ~ > claims, arranging a temporary by-passtpipe to extend from the by-pass connection'of the stopper to a location of the pipe-line downstream of said length, and substantially carrying out said work whilst the flow is by-passed through the by-pass pipe. ' - ':4'--.- -

1 5. The method of claim 14 in which the work comprises replacement of said length, and the bypass pipe is arranged to extend through said length prior to breaking up of said length. s

16. The method of claim 15 in which a further such stopper is employed at a position'further 'upstream of said length to shut off the flow whilst the first stopper is moved upstream, during relaying of a'pipe-line.

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17. A method of performing work on a length of sewage pipeline substantially as described with reference to Figure 7 or 8 of the accompanying drawings;