WO1993023729A1

WO1993023729A1 - Pipe testing and locating apparatus

Info

Publication number: WO1993023729A1
Application number: PCT/NZ1993/000036
Authority: WO
Inventors: Andrew Karl Dufresne
Original assignee: Andrew Karl Dufresne
Priority date: 1992-05-12
Filing date: 1993-05-12
Publication date: 1993-11-25
Also published as: AU4093993A

Abstract

An apparatus comprising a base unit (1) and a probe (2) connected to the base unit (1) by a cable (3). The base unit (1) and probe(2) can be towed along a main pipe (7) until the probe (2) is proximate a lateral pipe (10). The probe (2) may be launched into the lateral pipe (10) by launching means (26). Seals (4, 5) of the base unit (1) may then be inflated and fluid supplied via supply line (9) to the sealed zone to force the probe (2) along lateral pipe (10). A seal (54) about probe (2) may then be inflated to form a testing zone between the probe (2) and seals (4, 5). Tests may then be conducted above or below the probe (2) to test the integrity of the lateral pipe (10). The surface of the lateral pipe (10) may also be viewed via a CCTV camera (56) provided in the front of the probe (2). Methods of mapping the typography of the pipe and locating the position of the lateral pipe are also disclosed.

Description

PIPE TESTING AND LOCATING APPARATUS

TECHNICAL FIELD

This invention relates to an apparatus and method for investigating the condition, integrity or position of pipes. More particularly, but not exclusively, the invention relates to an apparatus for inspecting, testing and locating lateral pipes in a drainage system.

BACKGROUND OF THE INVENTION

Conventional drainage systems usually consist of a main pipe for each street or neighbourhood from which a number of lateral pipes project. The lateral pipes service individual properties or groups of properties. The main pipe usually has a minimum inner diameter of about 150mm and is fairly straight and readily accessible. Larger main pipes may have diameters exceeding 750mm. Access to the pipe is usually provided through manholes and the like in a street or private properties. The lateral pipes on the other hand are usually small (usually a minimum inner diameter of about 100mm) , quite often have bends in them, quite often extend at angles to the horizontal and are usually not accessible for testing or inspection without excavation. It is therefore very difficult and expensive to test for leaks in lateral pipes, to test if they are in use or not or to inspect them for structural damage or tree root intrusions. There is currently much concern with the problems caused by ex-filtration and infiltration. Ex- filtration is where sewage egresses from drainage pipes, polluting underground water supplies. Infiltration occurs when water Ingresses into the pipes of a drainage system. This may be a particular problem during and after heavy rainfall where ground water infiltrates into the sewage system, overloading the reticulation and sewage treatment facilities and causing raw sewage to overflow.

A. machine for testing lateral pipes of a drainage system (hereinafter referred to as the "hydrostatic testing machine") is disclosed in PCT/AU/91/00432. This specification discloses an apparatus suitable for performing a hydrostatic water test on a lateral pipe. The hydrostatic testing machine of that invention is similar to the base unit of the present invention. To conduct a hydrostatic test the machine is towed to a position in a main pipe where the seals are positioned on either side of a branch to a lateral pipe. The seals of the hydrostatic testing machine are then inflated to form a water tight seal in the section of pipe between the seals. Water is then admitted to this zone and the pressure in the zone is monitored. The amount of water which must be supplied to the zone to maintain a constant pressure is representative of the size of any leaks in the lateral pipe.

The hydrostatic testing machine has limitations. Firstly, the test pressure is limited to that which can be achieved hydrostatically. Secondly, the length of lateral pipe which can be tested is limited by the maximum allowable hydrostatic head. Thirdly, there is no provision for visual inspection of the lateral _ _

pipe. Fourthly there is no way of locating the position of the lateral pipe, and finally there is no way of transporting equipment and/or repair materials up the lateral pipe.

In this specification the term "fluid" is used to describe any liquid, gas or substance which can be transported through a pipe. It is to be appreciated that the present invention may find application in systems where the medium is gas, oil etc.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide an apparatus which overcomes or at least minimises some of the aforementioned disadvantages or at least provides the public with a useful choice.

According to a first aspect of the invention there is provided a pipe testing apparatus consisting of a base unit suitable for conveyance along a main pipe and a probe, the base unit comprising:

i) an elongate body

ii) a pair of sealing means spaced apart along said body capable of sealingly engaging the inner wall of a main pipe to form a sealed zone therebetween;

ϋi) winch means to wind and release a cable secured to said probe; iv) orienting and launching means to position said probe for conveyance along a lateral pipe; and v) fluid supply means which supplies fluid to the sealed zone;

said probe comprising;

i) a body suitable for conveyance along a lateral pipe branching from said main pipe; ii) viewing means provided in the end of said probe opposite the point of attachment to said cable; and iϋ) illumination means to illuminate the field of view of said viewing means.

In an alternate embodiment the viewing and illumination means may be provided on the base unit. The probe is preferably provided with a seal about its periphery and the base unit preferably includes a pressure transducer to test the pressure in the sealed zone. To enable pressure testing above the probe the probe may be provided with a pressure transducer at the front of the probe. A radio sonde transmitter may also be incorporated in the probe to enable the location of the lateral pipe to be determined.

According to a further aspect of the invention there is provided a method of inspecting a lateral pipe branching from a main pipe using the above apparatus comprising the steps of:

i) positioning the base unit within a main pipe so that the probe is proximate a junction to a lateral pipe. ii) positioning the probe in alignment with the lateral pipe using said orienting means; iii) actuating the launching means to advance the probe into the lateral pipe. iv) activating the sealing means to form a sealed zone in the section of the main pipe between the sealing means; v) introducing fluid via said fluid supply means to the sealed zone to propel the probe along the lateral pipe; and vi) viewing the condition of the lateral pipe via the viewing means.

According to another aspect of the invention there is provided a method of testing the integrity of a section of pipe according to the above method wherein the following steps replace step vi:

vi) at a desired point along said lateral pipe actuating the seal about said probe to form a testing zone between the seal of said probe and the seals of said base unit; vii) supplying fluid to the testing zone via said fluid supply means; and viii) monitoring the amount of fluid required to maintain a constant pressure in said testing zone.

According to a further aspect of the invention there is provided a method of testing the integrity of a section of pipe according to the above method wherein step (vi) is replaced by the steps: __g_

vi) at a desired point along said lateral pipe actuating the seal about said probe to form a fluid-tight seal between the probe and the lateral pipe; vii) supplying fluid into said lateral pipe at a point upstream of said probe; and viii) monitoring the pressure measured by said pressure transducer of said probe and the amount of fluid required to keep the pressure constant.

According to further aspects of the invention a method of locating pipes using a radio sonde, and methods of mapping the topography of pipes are disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example with reference to the accompanying drawings in which:

Figure 1: shows a simplified schematic view of the apparatus according to a preferred embodiment of the invention in use in a drainage system.

Figure 2: shows the drain testing apparatus of the invention according to a first embodiment. Figure 2a: shows a schematic view of the supply lines of the base unit shown in figure 2.

Figure 3: shows the drain testing apparatus of the invention according to a second embodiment.

Figure 4: shows the drain testing apparatus of the invention according to a third embodiment.

Figure 5: shows a cross-sectional view of the drain testing apparatus of figure 2.

Figure 6: shows a side view of the probe according to a preferred embodiment.

Figure 6a; shows a cross-sectional view of preferred seal assembly for the probe.

Figure 7: shows an orienting and launching means for launching the probe into a lateral pipe.

Figure 8: shows in perspective the cradle shown in figure 7.

Figure 9: shows a control unit for controlling the apparatus of figure 2,3 or 4.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring firstly to figure 1 the general operation of a preferred embodiment of the invention will be —b—

described. The pipe testing apparatus consists of a base unit 1 and a probe 2. The probe 2 is connected to the base unit 1 by a cable 3. The base unit is provided with sealing means at each end consisting of pairs of inflatable seals 4 and 5 which define a sealed zone 6 therebetween when inflated.

In use the probe 2 is initially retracted and is positioned within the cylindrical surface defined between sealing means 4 and 5. The base unit and probe are inserted in the main pipe 7 and towed along the main pipe by cable 8, attached to one end of the base unit. The base unit is towed along main pipe 7 until probe 2 is proximate the point of entry to the lateral pipe 10. This can be observed by a viewing means provided in the probe or on the base unit. Preferably this viewing means is a CCTV camera.

When the probe is proximate the point of entry to the lateral pipe it is positioned in line with and launched into the lateral pipe by an orienting and launching means (not shown in this drawing) . Sealing means 4 and 5 are preferably inflated by air supplied through a hose of supply line 9. This forms a sealed zone 6 between the seals 4, 5. Fluid is then supplied to the sealed zone 6 via another hose of supply line 9, which fluid is forced up the lateral pipe and forces the probe along the lateral pipe. Whilst the probe travels along the lateral pipe, or as it is retracted, the condition of the pipe may be observed via a CCTV camera mounted in the probe. ___

The probe 2 may be provided with sealing means to enable it to form a fluid tight seal against the walls of the lateral pipe. In a selected position fluid supply to the testing zone may be reduced and the sealing means of the probe 2 activated. In this way the pipe section consisting of the sealed zone 6 and the section of the lateral pipe up to the probe forms a closed testing zone. Fluid may be supplied to the testing zone via a fluid supply line in supply line 9. A pressure transducer in the base unit may monitor the pressure in the testing zone and supply a signal back to a control unit along supply line 9. At the control unit the amount of fluid required to be supplied to the testing zone to maintain a constant pressure in testing zone can be monitored. The amount of fluid required to maintain a constant pressure indicates the size of any leak in the lateral. Such tests may be conducted at various points along the lateral pipe to determine points of leakage. Once hydrostatic testing is completed the probe seal may be deflated and the probe returned to the base unit by winching in the probe via cable 3.

Referring now to figure 2 a first possible embodiment will be described. Skids 11 and 12 are provided at either end of elongate body 13. These skids ensure that the inflatable seals 14 to 17 do not impede the progress of the apparatus along a main pipe and ensure the seals are not exposed to abrasive surfaces along the pipe wall during towing. When inflated however, the seals 14 to 17 expand to a size extending below skids 11 and 12. Supply line 18 supplies fluid, air, electrical power and transmits and receives signals between the apparatus and a control unit. The various supply lines __IQ_

contained in supply line 18 are shown in more detail in figure 2a.

Pressure transducers 19 and 20 are provided between inflatable seals 14 and 15 and 16 and 17 respectively. This arrangement is the same as that employed in the hydrostatic testing machine. This arrangement is preferred as when a pair of seals, for example 14 and 15, are inflated the pressure between the seals can be measured by transducer 19. If a good seal has been formed the inflation of inflatable seals 14 and 15 reduces the volume between the seals and thus an increased pressure will be detected. If however a good seal has not been formed a pressure increase will not be detected. In this way it can be ensured that any detected leakage within the testing zone is not due to faulty sealing by seals 14, 15 and 16, 17. It is to be appreciated however that the use of two inflatable seals having a transducer therebetween is the preferred embodiment. A single seal could be used. Such a seal could use an alternative mechanism, such as the compression of a resilient ring to force it to expand to seal against the wall of a pipe.

An outlet 21 may be provided to supply fluid from supply line 18 to the sealed zone 22. Pressure transducer 23 measures the pressure in the sealed zone 22 and supplies signals indicative of the measured pressure to the control unit via supply line 18.

Probe 24 is supported by cradle 25, which is mounted to orienting means 26. Orienting means 26 includes first arm 27, second arm 28 and base 29. First arm 27 is rotatable with respect to second arm 28 as indicated by arrow B. Second arm 28 is rotatable about base 29 as indicated by arrow A. Cradle 25 is mounted to ram 48 of arm 27 by mounting bracket 48a.

A cable 30 is connected to probe 24. This cable supplies power and control signals to the probe and carries data from the probe to the base unit. Cable 30 is wound on to a drum 31. A slip ring assembly 32 at one end connects the conductors of cable 30 to conductors 44 (see figure 2a) of supply line 18. At the other end the drum is rotated by a motor and gear box assembly 33. Guide means 34 consists of a pulley which guides cable 30 onto the drum 31 as it is wound thereon. Guide 34 moves back and forward along shaft 35 to ensure that the cable is evenly wound thereon. An intelligent motor arrangement (not shown) drives guide means 34 back and forth in the directions indicated by arrow C to ensure that the cable is wound evenly. A double pulley guide 36 is provided on arm 27 to guide the cable as the probe moves along a lateral pipe. The two pulleys of double pulley guide 36 are spaced apart in the lateral direction of body 13 (in the position shown in figure 2). Cable 30 passes through the middle of the two pulleys which support cable 30 therebetween.

Referring now to figure 2a a schematic diagram showing the supply lines and cabling for the apparatus shown in figure 2 is shown. Supply line 18.includes a fluid supply line 37 which supplies fluid to outlet 21. Air supply line 38 supplies air to inflatable seals 14 to 17. Electrical supply line 39 contains power lines, control lines and data lines. Signals from pressure transducers 19, 20 and 23 are supplied to the control unit via lines 40, 42 and 41. Control signals to drive orienting means 26 are provided through cable bundle 42a and control signals to drive winch motor 33 are supplied via cables 43. Power, control and data lines connected to slip ring 32 are supplied by cable bundle 44.

This cable may include a co-axial cable to receive data from a CCTV camera, power cables for illumination, an internal pump and a radio sonde, and data lines from a pressure transducer in the probe. Although in this example individual control and data lines are shown it is to be appreciated that the electrical cables could consist merely of two power supply lines and a single data line upon which all information and control signals are transmitted and received. This data line could be a coaxial line carrying both CCTV, control and data signals. Alternatively, one separate data line could be provided in addition to a coaxial cable (and the two power lines) .

Referring now to figure 5 a cross-sectional view of body portion 13 is shown. It will be seen that two cavities 45 and 46 are provided within body section 13. These cavities enable the air supply line 38 and electric cables 42, 43, 44 and 42a to be ducted neatly through the unit. These cavities also allow cables to be ducted through the base unit to the other side (e.g. to allow cables to be ducted through the base unit to a winch on the other side) . Skids 11 and 12 upon which the base unit rides are also shown.

Referring now to figure 9 the control panel of a control unit for controlling the apparatus shown in figure 2 is shown. The control unit is connected to supply line 18 which supplies air, fluid, electrical power and control signals and receives data signals from the base unit. The control unit includes a CCTV display unit 100 to display the image received from a CCTV camera in the probe. Switch 101 enables air to be supplied to seals 14 to 17 for inflation. Displays 102 and 103 display the pressure values received from transducers 19 and 20. Meter 104 displays the angle of inclination of the probe where an inclinometer is included. Meter 105 displays the pressure measured by a pressure detector in the probe (60 in figure 6). Meter 106 displays the pressure measured by pressure transducer 23. It is to be appreciated that the analogue meters shown could be replaced by digital meters or other display means. The information displayed on meters 102 to 106 and displays 107 and 117 could all be displayed on CCTV 100 in defined display windows. Display 107 displays the value of a shaft encode connected to the winch. This represents the length of cable that has been released, and hence the distance the probe has travelled up the lateral pipe. Display 117 displays the fluid flow rate through line 37.

Joystick 108 is provided to control the orienting arm 26 of the base unit. Lateral movement causes rotation of the arm about base 29 in the direction indicated by arrow A. Vertical movement causes rotation in the direction indicated by arrow B.

Switch 109 enables the advance and retraction of ram 48 (see figure 7). Lever 110 controls the operation of the winch. Movement up or down causes the winch to wind or unwind the cable. Movement across into recess 111 places the winch in neutral. Lever 112 controls the fluid supply via line 37 to the testing zone. Switch 113 actuates and deactuates the clamps of the probe (58 and 59 in figure 6). Switch 114 operates the illumination means of the probe (55 in figure 6). Switch 115 actuates the radio sonde within the probe. Switch 116 actuates the pump of the probe to inflate its seal. When switched back the seal is deflated.

Referring now to figure 7 the operation of the orienting means will be described in more detail. Base section 29 of the orienting means includes a drive assembly which can rotate arm 28 about base section 29 as indicated by arrow A. A further drive assembly 47 is provided between arms 27 and 28 and rotates arms 27 and 28 relative to one another in the direction indicated by arrow B. Preferably the drive assemblies are electric motors with suitable gearing means, but may be hydraulically driven etc. Arm 27 further includes a ram 48 connected to cradle 25. The cable 30 connected to probe 24 passes under the "v" 49 of cradle 25\

When first placed in a main pipe probe 24 may be oriented longitudinally with respect to base 13 as shown in figure 2. At the control unit a user may manipulate joystick 108 to control the motor in base 29 to rotate arm 28 so that the probe faces towards the inner wall of the main pipe. In this position ram 48 is retracted and the probe is within the cylinder defined between the seals 15 and 16. As the base unit is towed through a main pipe an operator can view the pipe⁰as seen by a CCTV camera in the front of probe 24 through monitor 100. Preferably probe 24 includes illumination means and a CCTV camera (55 and 56 respectively in figure 6). When an operator sees via CCTV display 100 that the camera is proximate a desired lateral pipe 51 towing of the base unit ceases. Via joystick 108 the operator controls motor 47 so that arm 27 is rotated with respect to arm 28 to align the probe with lateral pipe 51. When an operator views on display 100 that the probe is aligned with lateral pipe 51 the operator actuates ram 48 via switch 109 to advance probe 24 into the lateral to the position shown in figure 7. The motor drive assembly 33 (see fig. 2) of the winch is then released so that drum 31 may freely rotate. Seals 14 to 17 of the base unit are then inflated by switching switch 101. The operator then operates lever 112 to supply fluid to testing zone 22 via supply line 37. As the water pressure builds up the escaping fluid forces probe 24 along lateral pipe 51.

Referring now to figure 6 a preferred probe construction is shown. The probe body 52 is preferably of substantially cylindrical cross- section of a diameter suitable to pass through bends in lateral pipes. A plurality of evenly spaced wheels 53 may be provided about the periphery of the body 52 at either end. These minimise the contact of the body of the probe with the wall of a lateral pipe. At the rear the probe is connected to a cable 30. Preferably, the cable includes a co-axial cable to carry CCTV camera signals as well as electrical control lines and electrical data lines. At the front of the probe is provided a seal 54.

According to a preferred embodiment (see figure 6a) a small internal pump 123 may be provided in the probe which is driven electrically by an electrical supply line in cable 30. The pump 123 may be connected to a small fluid reservoir 125 via hose 124- Fluid from reservoir 125 may be pumped into inflatable tube 121 via hose 122 which on expansion forces resilient ring 120 against the lateral pipe. Thus a fluid-tight seal may be formed between the probe and the lateral pipe. Alternatively an air —lb-

supply line could be included in cable 30 to inflate seal 54 with air. This would however increase the thickness of cable 30, and so would not be preferred where the available space is limited. Illumination means 55 and viewing means 56 are preferably provided at the front of the probe behind a transparent dome 57. The viewing means is preferably a CCTV camera. It is to be appreciated that in other embodiments the viewing means 56 may consist of a lense with an optical fiber conveying visual information back to the control unit. A second CCTV camera 56a may be provided in the rear of the probe for positioning the probe and viewing the lateral pipe in case the front camera is obstructed.

Clamps 58 and 59 will preferably also be provided. Clamp 58 will work in combination with a clamp opposite to it on the other side of the probe. Likewise clamp 59 will have another clamp opposite it on the other end of the probe. These clamps may be driven by electromagnets to force feet against the side of a lateral pipe to hold the probe in position whilst allowing fluid to pass (when inflatable seal 54 is deflated) .

In case power supply to the probe fails a security mechanism may be provided to ensure that seal 54 can be deflated to enable the probe can be retracted. The probe may be provided with a mechanism which deflates probe seal 54 when cable 30 is pulled with a certain force. For example, when cable 30 is pulled with a certain force a release valve may be activated to allow seal 54 to be deflated. In this way it is ensured that the probe can be recovered by activating the winch should there be a failure in __ __

the electric cable to the probe. The probe may also include an inclinometer to measure the gradient of the pipe the probe is travelling through. Further, the probe may be provided with a radio sonde transmitter to enable the position of the lateral pipe to be located at the surface using a receiver.

In this embodiment a base unit has been described in which fluid, air, electrical power and control and data lines are connected to the base unit from a control unit via supply line 18. It is to be appreciated however that the base unit could have an internal power supply and control and data signals could be transmitted wirelessly. A battery supply could be included in the base unit with seals 14 to 17 being inflated by an internal pump. Fluid could be supplied to the test zone 22 from the left side of seal 14 via a pump also. Control and data signals could be transmitted to and from the base unit wirelessly. Further, rather than being towed by cable 8 or supply line 9 the base unit could be driven by a suitable traction unit. The arrangement previously described is however preferred for its simplicity of construction, reliability and performance.

The operation of the apparatus in conducting a pipe integrity test will now be described. The base unit with probe in the retracted position is initially placed within an opening to main pipe 1. An operator may manipulate joystick 108 to drive the motor in base 29 to rotate arm 27 so that the probe is rotated to view the side wall of the main pipe. The base unit may then be towed by cable 8 until the probe is proximate a junction to a lateral pipe. This is observed by an operator who views the scene ___ __

as seen by the CCTV camera 56 of probe 24, which transmits a video signal via cable 30 and supply line 18 to the control unit, where it is displayed on a monitor 100. The operator then controls drive means 47 via joystick 108 to move arm 27 relative to arm 28 so that the probe is aligned with the lateral pipe 51. The operator then actuates ram 48 via switch 109 to advance probe 24 into lateral pipe 51. The operator then actuates switch 101 to supply air via air supply line 38 to seals 14 to 17, which inflate to form fluid-tight seals with the main pipe. The operator monitors the pressure between seals 14 and 15 and 16 and 17 from pressure transducers 19 and 20 respectively on meters 102 and 103 to ensure that a fluid-tight seal has been achieved. Lever 110 is moved to position 111 to place winch motor 33 in neutral so that cable 30 may be easily released, to allow the probe to travel along the lateral pipe. The operator then introduces fluid to the sealed zone 22 via supply line 37 by shifting lever 112 to the open position. The sealed zone fills with the fluid and forces the fluid along lateral 51. This fluid forces probe 24 along lateral 51. If there is difficulty in forcing the probe along the lateral pipe the probe seal 54 may be partially inflated (by temporary actuation of switch 116) so that the amount of water that can flow between the seal and the lateral pipe wall is reduced. As the probe travels along lateral pipe 51 its condition may be monitored by an operator viewing the images received from CCTV camera 56 transmitted over the co-axial cable to CCTV monitor 100 at the control unit.

When the probe reaches a desired position in the lateral pipe fluid supplied to the testing zone via fluid supply line 37 may be reduced or stopped by moving lever 112 in the opposite direction. The _. _g_

operator may then actuate inflation switch 116 on the control unit which supplies power via supply line 18 and cable 30 to the pump of probe 24. This causes the pump to inflate seal 54 with fluid from an internal reservoir. The seal 54 forms a fluid- tight seal between the probe and the lateral pipe 51. The supply of fluid to the testing zone via fluid supply line 37 may then recommence or increase by moving lever 112 towards the open position. The pressure within the testing zone may be monitored by an operator by monitoring the signal received from pressure transducer 23 displayed on meter 106. The amount of fluid required to be supplied to maintain a constant pressure in the testing zone indicates the size of any leak in the lateral pipe (assuming no leakage in the main pipe) . The fluid flow rate in supply line 37 may be displayed on display 117. Once a test has been completed the seal 54 of the probe may be deflated and the probe may be advanced further along the lateral pipe by supplying more fluid to the testing zone via fluid supply line 37. Probe seal 54 may then be reinflated and a further test conducted as described previously. If a number of such tests are conducted along the length of the pipe a region of leakage can be identified (i.e. a transition where a greater supply of fluid is required to maintain a constant pressure in the testing zone) . The control unit may include microprocessor control means as well as means to record the results of tests conducted and video recording means to record the information received from the CCTV camera of the probe.

It will be appreciated that a test carried out in the manner described above enables tests at greater than the available hydrostatic pressure to be ___ __

conducted. Furthermore, by conducting tests at various points along the pipe enables the precise region of failure to be located. Where a fault is located in a pipe, either by testing or by visual inspection,^"the invention also provides a method of physically locating the position of a pipe. Once a fault is located an operator may actuate switch 115 to send a control signal along supply line 18 and line 30 to probe 24 to drive a radio sonde. The signal transmitted from the radio sonde may be detected at ground level with a receiver. The position of a fault may be located by finding the point where the signal from the radio sonde is received most strongly.

Where the maximum length of cable 30 has been deployed or the maximum permissible hydrostatic head has been reached the invention also allows hydrostatic tests to be conducted above the probe. When the probe is positioned at such a point seal 54 may be inflated. Fluid may then be supplied to the lateral pipe at a point of access above the probe, for example an opening to the lateral pipe on a residential property. The pressure above the probe may be monitored by pressure transducer 60 in the front of the probe, which may supply pressure information data to the control unit via cable 30 and supply line 18 for display on meter 105. An operator can monitor the amount of fluid required to be supplied to the point of access above the probe to maintain a constant pressure, and thus obtain an indication of the amount of fluid escaping from the lateral pipe above the probe. The test can be conducted for different pressure heads to more precisely locate the area of failure. ___ _ _

The steps required to return the probe after conducting such a test will now be described. Firstly, clamps 58 and 59 are activated via switch 113 to secure the probe to the walls of the lateral pipe. Seals 14 to 17 of the base unit are then deflated by switching switch 101 in the opposite direction to release fluid below the probe. Fluid above the probe is then released by deflating probe seal 54. The probe is kept in place by clamps 58, 59. Seals 14 to 17 are then reinflated and fluid is supplied to the testing zone via supply line 37 to bring the water level back up to the level of the probe. Clamps 58 and 59 are then released and winch motor 33 is activated by shifting lever 110 to tow the probe back to the base unit. The rear end of the probe is guided back into the cradle via flared portions 25a of cradle 25. A microswitch may be provided on the cradle to indicate when the probe has been returned to the cradle. Driving of the winch motor 33 may then be deactivated. Ram 48 then withdraws the probe back to the base unit. Seals 14 to 17 are deflated and the apparatus may be towed to a recovery site.

Although semi-automated operation has been described above it is to be appreciated that the apparatus of the present invention may be controlled by a highly automated control unit. The control unit may be computer controlled with suitable input/output cards of the computer controlling electronic controls or valves which may control fluid or air supply to the base unit. Preferably, operation of the device can be controlled by macro programs. For example, a user may initiate a test macro. The computer may then control the valve which controls the supply of fluid via line 37 to the testing zone. The computer _₂__

may control the amount of fluid supplied to the testing zone to maintain a constant pressure (pressure information from transducer 23 being supplied to the computer) . The computer may automatically conduct a number of such tests for a number of test pressures. Likewise, the computer may control inflation of the seals of the base unit. An initial volume of air may be rapidly supplied to the seals for rapid inflation. The last volume of air may be supplied slowly to control inflation over the last portion. Thus tests may be conducted more rapidly. All of the controls 101 and 108 to 116 may be replaced by a computer keyboard and/or mouse and/ or joystick in a fully automated embodiment. Control actions may be initiated by pointing to the desired function using a mouse and actuating that function by depressing a button of the mouse. It should be appreciated that the apparatus of the invention may be controlled via purely manual controls, by a highly automated computer controlled control unit or by a semi-automated control unit falling somewhere between the two.

Four types of uses of the apparatus have been described above. In a first application a testing zone is formed between the probe and the seals of the base unit to allow pressure testing of the section of lateral pipe below the probe. In the second application hydrostatic testing of the lateral pipe above the probe may be performed by supplying fluid to the lateral pipe above the probe and monitoring the pressure as measured at the probe. Thirdly, the apparatus allows for visual inspection of lateral pipes. Finally, there is disclosed a use of the apparatus to locate^'lateral pipes using a radio sonde and a receiving unit. __ __

Further to these uses the apparatus may be used for mapping typography of the lateral pipe. A rotary encoder may be provided on the winch so that the length of cable 30 released can be measured. In this way the distance of the probe along the lateral pipe can be monitored. If an inclinometer is included in the probe then the gradient of the pipe at various stages can be recorded with the value from the rotary encoder representative of the distance travelled by the probe along the lateral pipe.

Alternatively, the typography of the lateral pipe may be determined by clamping the probe at a test position along the lateral pipe with seal 54 being deflated. Fluid may be released from the testing zone until the water level is level with the front of the probe, as seen through the CCTV monitor by an operator controlling the apparatus. The pressure measured in the testing zone by pressure transducer 23 will then give a figure representative of the height of the lateral pipe at the test point relative to the test zone.

Using measurements made by either method the typography of the lateral pipe may be mapped. This allows the elevation of the lateral pipe to be mapped at a variety of longitudinal test points. To map the lateral position of the pipe the radio sonde in the probe may be used in conjunction with a receiver. This data may be recorded by recording means in the control unit.

Referring now to figure 3 an alternate embodiment is shown in which the cable attaching the probe to the _₂₄__

base unit is fed via a capstan rather than a winch drum. The base unit shown in figure 3 is substantially the same as the base unit shown in figure 2 except for the difference in the winching means. Instead of a winching drum a capstan 61 driven by motor and gearing means 62 releases and winds in cable 30. In this case cable 30 must be separate from and move with respect to supply line 18 to enable cable to be moved to and from the control unit as cable is released or wound in. This arrangement has the advantage of avoiding the need for the slip rings of the apparatus shown in figure 2. It does however require slack cable to be wound onto a reel at the control unit or released as the probe is advanced. Further, capstan 61 will need to be driven to release cable to allow the probe to advance along a lateral pipe. Otherwise operation is the same as for the apparatus shown in figure 2.

Referring now to figure 4 a further embodiment is shown. This embodiment may be used where the apparatus must fit within a very small main pipe. The winch arrangement is similar to that shown in figure 2. Where space is particularly confined it may not be possible to guide the cable around pulleys. In such situations it may be necessary to employ the configuration shown in figure 4.

In this case winch drum 63 is mounted on axis 64 which allows the drum to move to and fro in the directions indicated by arrow D. This may be achieved by shaft 64 having a non-circular cross section which is of constant cross-section along its length, with the portion of drum 63 engaging the shaft being of the same cross section. In this way the drum is rotated by rotation of shaft 64 but _ _

moveable axially therealong. Shaft 64 may be driven by motor and gearbox 65 and slip rings 66 may connect the conductors of cable 30 to conductors of supply line 18. In this case a certain amount of loose cable may be provided between slip rings 66 and mount 67 to enable the drum to move as indicated by arrow D. This loose cable may be wound loosely in a helix about shaft 64. Alternatively, a spring loaded drum may supply and retract cable to slip rings 66 as they move to and fro. An alternative arrangement for the winch is to have a central stationary shaft which is fixed to the body of the base unit and along which the winch drum can move axially. The method of moving the winch drum axially as it rotates is preferably by means of continuous left-hand and right-hand screw threads on the stationary shaft which are engaged by a protrusion at the end of the winch drum. At the centre point of the axial span of travel of the winch drum, a motor is fixed to the stationary shaft. The motor drives a toothed gear wheel which engages an axially aligned internal spline cut into the interior circumference of the winch drum. The motor affixed to the stationary shaft, when activated, rotates the toothed gear wheel, which in turn rotates the winch drum. The continuous spline cut into the inner circumference of the winch drum allows the winch drum to move axially along the shaft whilst rotating without disengaging the driving gear on the motor.

Operation of the apparatus shown in figure 4 is generally the same as for the apparatus shown in figures 2 and 3. The method of launching and releasing the probe is however slightly different due to the different construction. The probe is launched to the position shown in figure 7, as previously described. Once launched to the position shown in figure 7 inflatable seal 54 is however inflated to hold the probe in place. Alternatively the probe may be held in place by activating clamps 58 and 59. Ram 48 is then retracted to retract the cradle from the probe. When the cradle is free of the probe the base unit is towed further along the main pipe by supply line 18 until the probe is just to be right of rim 68 of drum 63. The seals of the base unit are then inflated, winch drum 63 is allowed to freely rotate and fluid is introduced to the test zone. Inflatable seal 54 is then deflated and the probe is propelled along the lateral pipe.

As cable is released from drum 63 it moves to the left to ensure that the point of unwinding of the cable remains opposite the junction to the lateral pipe. Winch drum 63 is thus driven back and forth to ensure the point of unwinding is opposite the lateral pipe. Likewise, when cable is rewound the drum is driven back and forth to evenly wind cable 30 along drum 63.

Tests may be conducted in the same manner as previously described. When returning the probe to the base the probe is wound in until part of the back of the probe extends into the main pipe. In this embodiment a CCTV camera may be provided in the rear of the probe to enable positioning of the apparatus for recovery of the probe. When an operator can see from the rear CCTV camera that the probe has entered the main pipe the driving of the winch may be stopped. Inflatable seal 54 is then inflated. Drum 63 is again allowed to freely rotate. The base unit is then towed by line 8 along the main pipe until the cradle can be seen opposite the probe through the rear CCTV camera of the probe. Ram 48 is then actuated and the probe is guided into the cradle via flanged portions 25a. Once the probe is within the cradle 25 seal 54 may be deflated and ram 48 driven to retract the probe. The base unit may then be towed out and recovered in the usual way.

As well as being useful for inspection, testing the integrity of pipes, locating pipes and mapping the typography of pipes the apparatus of the invention may be useful in transporting materials and equipment to repair pipes. The probe of the invention could be used to carry repair materials to a faulty section of pipe and apply the repair materials to the pipe.

The invention thus provides a method and apparatus which can locate points of leakage in a lateral pipe extending from a main pipe. The invention also provides means for locating the point of leakage using a radio sonde. The apparatus also allows visual inspection of lateral pipes as well as mapping of the typography of lateral pipes.

Where in the foregoing description reference has been made to integers or components having known equivalents then such equivalents are herein incorporated as if individually set forth.

Although this invention has been described by way of example it is to be appreciated that modifications may be made thereto without departing from the scope of the invention as defined in the appended claims.

INDUSTRIAL APPLICABILITY

Although the method and apparatus of the invention may find application in a wide variety of systems, the invention is considered particularly suitable for use in testing locating and inspecting lateral pipes of a drainage system.

Claims

1. A pipe testing apparatus consisting of a base unit suitable for conveyance along a main pipe and a probe, the base unit comprising:

i) an elongate body ii) a pair of sealing means spaced apart along said body capable of sealingly engaging the inner wall of a main pipe to form a sealed zone therebetween; iii) winch means to wind and release a cable secured to said probe; iv) orienting and launching means to position said probe for conveyance along a lateral pipe; and v) fluid supply means which supplies fluid to the sealed zone;

said probe comprising;

i) a body suitable for conveyance along a lateral pipe branching from said main pipe; ii) viewing means provided in the end of said probe opposite the point of attachment to said cable; and iii) illumination means to illuminate the field of view of said viewing means.

2. An apparatus as claimed in claim 1 wherein the testing apparatus is connected to a control unit by a supply line which includes a fluid supply line which supplies fluid to said fluid supply means, air supply means to inflate said sealing means and electrical cables. ___g_

3. An apparatus as claimed in claim 1 or claim 2 wherein the probe is provided with a seal about its periphery which can be activated to form a fluid tight seal with the wall of a lateral pipe and said base unit includes a pressure transducer mounted to enable the pressure in the sealed zone to be measured.

4. An apparatus as claimed in any one of the preceding claims wherein the probe includes a pressure transducer positioned at the end of said probe opposite the point of attachment of said probe to said cable.

5. An apparatus as claimed in any one of the preceding claims wherein the sealing means each consist of a pair of inflatable seals and a pressure transducer is provided between each pair of inflatable seals to test the integrity of the seal formed by each pair of seals.

6. An apparatus as claimed in any one of the preceding means wherein a viewing means is provided in the end of the probe connected to the cable.

7. An apparatus as claimed in any one of the preceding claims wherein the cable between said winch means and said probe includes electrical conductors to supply control signals and to receive data from said probe.

8. An apparatus as claimed in the any one of the preceding claims wherein the probe includes electrically driven pump means to inflate the seal about said probe.

9. An apparatus as claimed in any one of the preceding claims wherein the viewing means is a television camera.

10. An apparatus as claimed in any one of the preceding claims wherein said orienting means comprises an arm rotatable at its base about a transverse axis of said base unit, said arm consisting of two sections being rotatable relative to one another about an axis transverse to the axis of rotation about the base.

11. An apparatus as claimed in claim 10 wherein the launching means comprises a ram connected between the distal end of said arm and said cradle which can advance the probe into a lateral pipe.

12. An apparatus as claimed in any one of the preceding claims wherein the probe includes clamps to secure the probe at a given position along a lateral pipe.

13. An apparatus as claimed in any one of the preceding claims wherein a plurality of wheels are provided evenly spaced about the periphery of either end of said probe.

14. An apparatus as claimed in any one of the preceding claims wherein an inclinometer is incorporated in the probe.

15. An apparatus as claimed in any one of the preceding claims wherein said winch includes means which monitors the length of cable released.

16. An apparatus as claimed in any one of the preceding claims wherein a radio sonde transmitter is provided in the probe. __{3 ι}_

17. An apparatus as claimed in any one of the preceding claims including a towing cable connected to one end of the base unit to tow it along a main pipe.

18. An apparatus as claimed in claim 2, said control unit including display means to display data received from the base unit and probe and actuation means to control the base unit and probe.

19. A pipe testing apparatus consisting of a base unit suitable for conveyance along a main pipe and a probe, the base unit comprising:

i) an elongate body ii) a pair of sealing means spaced apart along said body capable of sealingly engaging the inner wall of a main pipe to form a sealed zone therebetween; iii) winch means to wind and release a cable secured to said probe; iv) orienting and launching means to position said probe for conveyance along a lateral pipe; and v) fluid supply means which supplies fluid to the sealed zone; vi) viewing means having a field of view enabling an operator to view the operation of the orienting and launching means; vii) illumination means to illuminate the field of view of the viewing means; and __₂_

viii) a pressure transducer mounted to enable the pressure in the sealed zone to be measured; and said probe comprising: i) a body suitable for conveyance along a lateral pipe branching from said main pipe; and ii) a seal about the periphery of the probe which can be activated to form a fluid- tight seal with the wall of a lateral pipe.

20. A method of inspecting a lateral pipe branching from a main pipe using the apparatus of claim 1 comprising the steps of:

i) positioning the base unit within a main pipe so that the probe is proximate a junction to a lateral pipe. ii) aligning the probe with the lateral pipe using said orienting means; iii) actuating the launching means to advance the probe into the lateral pipe. iv) activating the sealing means to form a sealed zone in the section of the main pipe between the sealing means; v) introducing fluid via said fluid supply means to the sealed zone to propel the probe along the lateral pipe; and vi) viewing the condition of the lateral pipe via the viewing means. _ _

21. A method as claimed in claim 20 wherein image data from the viewing means is transmitted via cable from the probe to a control unit where the image data is displayed and recorded.

22. A method as claimed in claim 20 or 21 wherein the probe is returned to the base unit by activating the winch means to tow the probe back to the launching means and then retracting the launching means.

23. A method of testing the integrity of a section of pipe using the apparatus of claim 3 comprising the steps of:

i) positioning the base unit so that the probe is proximate the branch of said main pipe with said lateral pipe; ii) aligning said probe with said lateral pipe via said orienting means; iϋ) actuating said launching means to advance said probe into said lateral pipe; iv) actuating said sealing means of said base unit to form a sealed zone therebetween in said main pipe; v) supplying fluid into the sealed zone to advance said probe along said lateral pipe; vi) at a desired point along said lateral pipe actuating the seal about said probe to form a testing zone between the seal of said probe and the seals of said base unit; __₄_

vii) supplying fluid to the testing zone via said fluid to supply means; and viii) monitoring the amount of fluid required to maintain a constant pressure in said testing zone;

24. A method as claimed in claim 23 wherein a further test is conducted at another point along the lateral pipe by deflating the probe seal and repeating steps (v) to (viii) of claim 23.

25. A method as claimed in claim 23 or claim 24 wherein the probe is retracted by deactuating the probe seal and winching the probe back to the base unit by the winching means, and then retracting said launching means.

26. A method as claimed in any one of claims 23 to 25 wherein the sealing means each consist of a pair of inflatable seals having a pressure detector therebetween, the output of the pressure detector being monitored as the seals are inflated to ensure a fluid-tight seal is achieved.

27. A method as claimed in any one of the claims 23 to 26 wherein the apparatus is connected via a supply line to a base unit and data received from the probe and base unit is recorded at the control unit.

28. A method of testing the integrity of a section of pipe using the apparatus of claim 4 comprising the steps of: ____

i) positioning the base unit so that the probe is proximate the branch of said main pipe with said lateral pipe; ii) aligning said probe with said lateral pipe via said orienting means; iii) actuating said launching means to advance said probe into said lateral pipe; iv) actuating said sealing means of said base unit to form a sealed zone therebetween in said main pipe; v) supplying fluid into the sealed zone to advance said probe along said lateral pipe; vi) at a desired point along said lateral pipe actuating the seal about said probe to form a fluid- tight seal between the probe and the lateral pipe; vii) supplying fluid into said lateral pipe at a point upstream of said probe; and viii) monitoring the pressure measured by said pressure transducer of said probe and the amount of fluid required to keep the pressure constant.

29. A method as claimed in claim 28 wherein a further test is conducted comprising the steps:

ix) activating clamps of the probe to secure the probe to walls of the lateral pipe; x) deactuating the seals of the base unit to allow fluid in the lateral pipe to be released; xi) deflating the seal about the probe to allow fluid above the probe to be released; xii) actuating the sealing means of the base unit; xiii) supplying fluid to the sealed zone to raise the fluid level to the level of the probe; xiv) releasing the clamps of the probe and continuing to supply fluid to advance the probe along the lateral pipe; xv) at a desired point along the lateral pipe actuating the seal about the probe to form a fluid-tight seal between the probe seal and the wall of the lateral pipe; xvi) supplying fluid into the lateral pipe at a point upstream of the probe; and xvii) monitoring the pressure measured by the pressure transducer of said probe and the amount of fluid required to keep the pressure constant.

30. A method as claimed in claim 28 or claim 29 wherein the probe is recovered by conducting the steps:

a) activating clamps of the probe to secure the probe to walls of the lateral pipe; _ __

b) deactuating the seals of the base unit to allow fluid in the lateral pipe to be released; c) deflating the seal about the probe to allow fluid above the probe to be released; d) actuating the sealing means of the base unit; e) supplying fluid to the testing zone to raise the fluid level to the level of the probe; f) deactivating the clamps; g) winching the cable connecting the probe to the base means via the winching means to return the probe to the base unit; and h) retracting the launching means.

31. A method of locating a pipe using the apparatus of claim 16 comprising the steps

i) positioning the base unit within a main pipe so that the probe is proximate a junction to a lateral pipe, ii) aligning the probe with the lateral pipe using said orienting means; iii) actuating the launching means to advance the probe into the lateral pipe, iv) activating the sealing means to form a sealed zone in the section of the main pipe between the sealing means; v) introducing fluid via said fluid supply means to the sealed zone to —-Jo-

propel the probe along the lateral pipe; vi) at a selected position along the lateral pipe activating the radio sonde to transmit; and vii) using a receiver, on the surface to locate the position of the probe.

32. A method of mapping the typography of a lateral pipe using the apparatus of claim 3, wherein said winching means includes means to measure the length of cable released and said probe includes clamping means, said method comprising:

i) positioning the base unit within a main pipe so that the probe is proximate a junction to a lateral pipe, ii) aligning the probe with the lateral pipe using said orienting means; ϋ ) actuating the launching means to advance the probe into the lateral pipe, iv) activating the sealing means to form a sealed zone in the section of the main pipe between the sealing means; v) introducing fluid via said fluid supply means to the sealed zone to propel the probe along the lateral pipe; and vi) activating said clamps to secure said probe to the lateral pipe; vii) adjusting the fluid level in the lateral pipe so that it is proximate the level of said viewing means; _ _

viii) monitoring the pressure transducer of said base unit and recording the measured pressure value against the output of said means to measure the length of cable released; ix) releasing the clamps; and x) repeating steps (v) to (ix) to obtain a required number of samples.

33. A method of mapping the typography of a lateral pipe using the apparatus of claim 3, wherein said winching means includes means to measure the length of cable released and said probe includes an inclinometer, said method comprising:

i) positioning the base unit within a main pipe so that the probe is proximate a junction to a lateral pipe, ii) aligning the probe with the lateral pipe using said orienting means; iii) actuating the launching means to advance the probe into the lateral pipe, iv) activating the sealing means to form a sealed zone in the section of the main pipe between the sealing means; v) introducing fluid via said fluid supply means to the testing zone to propel the probe along the lateral pipe; and vi) for a number of positions along the lateral pipe recording the value output by the inclinometer against the value output by the means to measure the length of cable released.