WO2007139324A1

WO2007139324A1 - Testing apparatus of water proof for sewer and method thereof

Info

Publication number: WO2007139324A1
Application number: PCT/KR2007/002562
Authority: WO
Inventors: Bok Soon Kim
Original assignee: Tap Environment
Priority date: 2006-05-26
Filing date: 2007-05-28
Publication date: 2007-12-06
Also published as: KR20070113847A

Abstract

A watertight test apparatus and method for a sewer pipe are disclosed. The apparatus includes: a vacuum pump for creating a vacuum in the sewer pipe, whose both ends are sealed by packers, through a vacuum pipe that extends through the packer to the interior of the sewer pipe; a compressor for creating compressed air and inflating the packers, so that the packers can seal the inner walls of the sewer pipe; and a sensor for sensing leakage of air in the sewer pipe. The method includes: installing watertight inflation members with packers, and installing vacuum valves for controlling a vacuum pressure of the sewer pipe; installing the packers with both ends of the sewer pipe, respectively, and placing an autonomous roving vehicle in the sewer pipe to which a watertight sensor is mounted; inflating the watertight inflation members, and operating the vacuum valves to create a vacuum in the sewer pipe; and reading watertight values based on variation in ultrasonic waves detected by the ultrasonic sensor or on variation in the vacuum pressure, applying the read watertight values to a computer through a control board, in real-time, and displaying the watertight state of the sewer pipe.

Description

[DESCRIPTION]

[Invention Title]

Testing apparatus of water proof for sewer and method thereof

[Technical Field]

The present invention relates to an apparatus and method for testing a sewer pipe. More particularly, this invention relates to a watertight test apparatus and method for sewer pipes that seal both ends of a sewer pipe using packers, create a vacuum in the sewer pipe, and detect ultrasonic waves generated when air or water leaks into the vacuum sewer pipe, taking into account atmospheric pressure variation, thereby performing watertightness test of the sewer pipe easily.

[Background Art]

Sewer pipe's watertightness is required to protect the environment and water resource. To this end, there have been a technique for testing watertightness of a sewer pipe using a thermal sensor, issued as Korean Utility Model Registration No. 20-0306071, a technique for testing watertightness of a sewer pipe using a laser beam, issued as Korean Patent No. 10-0335685, a technique for detecting water leakage using an infrared sensor, issued as Korean Utility Model Registration No. 20-0413585, and a technique for testing watertightness of a sewer pipe using air pressure, issued as Korean Patent No. 10-0568608.

In particular, one of the most frequently used techniques is disclosed in Korean Patent No. 10-0187798, where the sewer pipe is sealed on both sides, filled with water, and then undergoes a watertight test. Such a technique is described referring to Figure.

As shown in Figure 1, an irrigation pipe 11 is installed to extend in the widthwise direction through a tube-type downstream end plug 10 that seals the downstream end of an antecedent test section a. An irrigation valve 12 is installed to the end of the irrigation pipe 11. The irrigation valve 12 is installed at the end portion of a connection element, in which the connection element is connected to a connection hose 30 whose both ends have a well- known one touch connection mechanism that can perform coupling/locking in one stroke and an unlocking/separating in another stroke.

All upstream end plugs 20 of a posterior test section b install an irrigation valve 21 that is different from a water supply valve 3 mounted at the front end of a water supply pipe 4. A check valve 22 is installed at the front end of the irrigation valve 21. The irrigation valve 21 is closed or opened when antecedent test water c is irrigated to the posterior test section b. The check valve 22 is communicated with the rear end of the irrigation valve 12 through the connection hose 30 and prevents the posterior test water d in the posterior test section b from flowing into the antecedent test section a. The check valve 22 includes a connection element at its front end, in which the connection element is coupled to the rear end of a connection hose 30 having a one-touch connection mechanism as is described above.

An air supply tip 23 is installed to the front end of a vent valve 5 that is installed to the front end of a vent pipe 6. The air supply tip 23 serves to inject compressed air, produced by a compressor 50 on the ground, into a section that has undergone the watertight test, so that the test water can be enforcedly transferred to the posterior test section b. Also, the air supply tip 23 serves to evacuate air from the posterior test section b, so that posterior test water d can be irrigated to the posterior test section b.

The connection hose 30 couples an irrigation water pipe 11 of a downstream end plug 10 at the antecedent test section a to a check valve 22 of a upstream end plug 20 at the posterior test section b. The connection hose 30 has one-touch connection mechanisms at both its ends, thereby performing the coupling/separating operations easily.

After completing the watertight test in the antecedent test section a, whose upstream and downstream ends A and B are sealed by the upstream and downstream end plugs 20 and 10, respectively, the posterior test section b undergoes the following processes: a upstream end plug 20' is inserted into its upstream end A' ; and a downstream end plug 10' is fitted into its downstream end B' , not shown; and air is injected into the plugs to inflate such that the plugs can seal both the ends of the posterior test section b. Here, the upstream end plug 20' and the downstream end plug 10' are the same type as those of the antecedent test section a. The rear end of the irrigation water valve 12 of the downstream end plug 10 and the front end of a check valve 22' of the upstream end plug 20' are coupled to the connection hose 30.

After that, the vent valve 5', a test pipe valve 9', and irrigation water valves 12 and 21' are opened, and a water supply valve 3' is closed. The antecedent test water c flows into the posterior test section b via the opened irrigation water pipe 11 and a water supply pipe 4'.

When the water level of the antecedent test section a is lowered to the upper end of the test pipe hose 40, the test pipe valve 9 is closed and the vent valve 5 is opened such that the pressure in the interior of the antecedent test section a can return to atmospheric pressure by the inflow air.

When the water level of the antecedent test section a is equal to that of the posterior test section b, the test water becomes stagnant. On this occasion, the water supply tip 23 at the upstream end plug 20 of the antecedent test section a is connected to the compressor 50 via an additional hose. As well, the test pipe valve 9, the water supply valve 3, and the irrigation water valve 21 are closed, and compressed air is injected thereto. Since the compressed air has been injected thereto, the remaining antecedent test water c flows into the posterior test section b. When a portion of posterior test water flows into the vent valve 5' of the posterior test section b, the vent valve 5' is closed such that the antecedent test water c cannot be irrigated thereto.

When the antecedent test water c has been transferred to the posterior test section b, the irrigation water valve 21' is closed. An insufficient amount of posterior test water due to a shortage in supply, although approximately small, can be replenished from a reservoir tank or a supplementary tank 8' as the irrigation water valve 21' is closed and the water supply valve 3' is opened. This replenishing is continued until the vertical test pipe 7' is inundated with the posterior test water d. After that, the posterior test section b undergoes a watertight test. And, the remaining sections retain the same watertight test as the posterior test section b.

As such, the conventional watertight test for a sewer pipe is performed by: sealing both ends of the sewer using the plugs; filling the sewer pipe with water; and performing a watertight test whether water leaks from the sewer pipe after a certain period of time elapses. To this end, the test water must be transferred from one sewer pipe to be tested to another sewer pipe to be tested. To transfer the test water, relatively high pressure must be applied to the sewer pipes while each sewer pipe is repeatedly closed and opened. Particularly, all the sewer pipes were not installed horizontally, but are installed on a steep incline at the sites. If the sewer pipes were installed on a steep incline, a relatively high compression pressure is needed to transfer the test water. When such a high compression pressure is applied to the sewer pipes, the plugs sealing the sewer pipes may be separated from the sewer pipes. In that case, the plugs can become a dangerous weapon, such as a cannon ball, and can be shot out toward workers or surrounding machines, which can cause injury workers or industrial disasters.

[Disclosure]

[Technical Problem]

Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a watertight test apparatus and method that create a vacuum in a pipe and test watertightness of the vacuum pipe, thereby reducing test time, installation/removal time of the apparatus, and test costs, but enhancing test precision, in comparison to a conventional watertight test apparatus and method that fill the pipe with water or air with a high pressure and test watertightness of the pressured pipe.

It is another object of the present invention to provide a watertight test apparatus and method that test watertightness of a pipe without using water, thereby allowing the watertight test to be performed in an area with little or no water.

It is another object of the present invention to provide a watertight test apparatus and method that create a negative pressure in a sewer pipe and test watertightness of the sewer pipe, thereby preventing packers sealing both ends of the sewer pipe from shooting, in comparison to a conventional watertight test apparatus and method that apply a high compression pressure to the sewer pipe, which may cause the packers to explosively shoot away from the sewer pipe.

It is another object of the present invention to provide a watertight test apparatus and method that test watertightness of a pipe without using a commercial power supply or an electric generator, as is configured in such a way that a vacuum pump and a compressor for inflating a packer are driven by rotational force from an engine of a vehicle, thereby performing the watertight test in a desert area or an interior, etc. [Technical Solution!

In accordance with an aspect of the present invention, the above and other objects can be accomplished by the provision of a watertight test apparatus for testing a sewer pipe including: a vacuum pump and a compressor integrally installed to a vehicle, which are operates by power transmitted from the engine of the vehicle through a clutch; packers for inflating by compressed air from the compressor and for sealing both ends of the sewer pipe! a vacuum valve for maintaining a vacuum pressure of the sewer pipe to which an evacuation pipe extends through the packer, connecting the vacuum pump to the sewer pipe; and a ultrasonic sensor mounted on an autonomous roving vehicle, for sensing ultrasonic waves generated in the sewer pipe during the watertight test.

In accordance with another aspect of the present invention, there is provided a watertight test apparatus for testing a sewer pipe including: a vacuum pump that creates a vacuum in the sewer pipe whose both ends are sealed by packers; a compressor that creates compressed air to inflate the packers, so that the inflated packers can seal the inner walls of the sewer pipe; and a sensor for sensing leakage of air in the sewer pipe.

Preferably, the vacuum pump and the compressor are driven by a vehicle engine. The vacuum pump and the compressor receive power from the vehicle engine through pulleys. The pulleys receive the power through an engine shaft and a clutch associated with the vehicle engine.

In accordance with another aspect of the present invention, there is provided a watertight test method for testing a sewer pipe including: installing watertight inflation members with packers, and installing vacuum valves for controlling a vacuum pressure of the sewer pipe; installing the packers with both ends of the sewer pipe, respectively, and placing an autonomous roving vehicle in the sewer pipe to which a watertight sensor is mounted; inflating the watertight inflation members, and operating the vacuum valves to create a vacuum in the sewer pipe; and reading watertight values based on variation in ultrasonic waves detected by the ultrasonic sensor or on variation in the vacuum pressure, applying the read watertight values to a computer through a control board, in real-time, and displaying the watertight state of the sewer pipe. [Advantageous Effects]

As described above, the watertight test apparatus and method according to the present invention can reduce test time, installation/removal time of the apparatus, and test costs, but enhance test precision, in comparison to a conventional watertight test apparatus and method that fill the pipe with water or air with a high pressure and test watertightness of the pressured pipe.

Also, the watertight test apparatus and method allow the watertight test to be performed in an area with little or no water.

In addition, the watertight test apparatus and method prevent packers sealing both ends of the sewer pipe from shooting, in comparison to a conventional watertight test apparatus and method that apply a high compression pressure to the sewer pipe, which may cause the packers to explosively shoot away from the sewer pipe.

Furthermore, since the watertight test apparatus and method is configured to include a vacuum pump and a compressor that are driven by power from a vehicle engine, the apparatus can operate without a commercial power supply or an electric generator and perform the watertight test in a desert area or an interior, etc. [Description of Drawings]

The above and other objects, features, and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which-'

Figure 1 is a cross-sectional view depicting a conventional watertight test apparatus for sewer pipes;

Figure 2 is a schematic block diagram depicting a watertight test apparatus for sewer pipes that creates a vacuum in a sewer pipe and tests the vacuum sewer pipe, according to the present invention;

Figure 3 is a schematic block diagram depicting a control board of a watertight test apparatus for sewer pipes, according to the present invention; and

Figure 4 is a cross-sectional view depicting a sewer pipe to which a watertight test apparatus for sewer pipes according to the present invention is applied. [Best Mode]

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a schematic block diagram depicting a watertight test apparatus for sewer pipes that creates a vacuum in a sewer pipe and tests the vacuum sewer pipe, according to the present invention. The watertight test apparatus is installed such that it can be associated with an engine of a vehicle as fol lows.

When a switch SW is turned on, an engine driver 101 inputs electric power from a battery Bl and generates a high voltage. The high voltage serves to ignite the ignition plugs 103 and thus the engine 102 starts to operate.

The engine 102 outputs its power through an engine shaft 104. The engine shaft 104 is coupled to a pulley 105 to transmit a rotational force of the engine output. A clutch 106 is installed close to the engine shaft 104, such that the clutch 106 receive the engine output to transmit it to corresponding parts, as occasion demands. The clutch 106 is fixed to a frame 107 of the vehicle, for example. The clutch 106 is configured to include: a fixing unit 108; and clutch pulleys 109 fixed to the fixing unit 108, for selectively transmitting power from the engine shaft 104 to corresponding parts.

The clutch pulleys 109 are connected to pulleys 111 and 121 through power transmission means, such as belts, to drive the vacuum pump 110 and the compressor 120.

The compressor 120 creates compressed air. When an air pressure valve Vl is opened, the compressed air passes through an air injection pipe 82 and inflates packers 70 to seal the interior of a sewer pipe 60. When the vacuum pump 110 is operated to create a vacuum pressure, a vacuum valve V2 is opened by the vacuum pressure. That is, the vacuum pump 110 evacuates air from the interior of sewer pipe 60 through the evacuation pipe 74 and creates a vacuum in the interior of the sewer pipe 60.

Figure 3 is a schematic block diagram depicting a controlling device of a watertight test apparatus for sewer pipes, according to the present invention. The battery Bl supplies DC power to a voltage regulator IC 131 that drops the DC power and maintains a constant voltage level, and to an inverter 132 that converts the DC power to AC power. The output voltage B2 of the voltage regulator IC 131, used as drive power, is supplied to a control board 133.

The inverter 132 is connected to an autonomous roving vehicle 140 via power cables 135 that are wound around a take-up reel 143. The AC power of the inverter 132 is supplied to the autonomous roving vehicle via the power cables 135. The autonomous roving vehicle 140 includes a CCTV camera 141 and a ultrasonic sensor 142. The ultrasonic sensor 142 is connected to an input port Pl of the control board 133 via a sensor cable 137. The CCTV camera 141 is connected to a computer 150 via a image signal cable 136. The computer 150 includes an image processing card that receives moving images from the CCTV camera 141, coverts the moving images to digital data, and stores the digital data therein. The power cables 135, the image signal cable 136, and the sensor cable 147 are wound by take-up reels, respectively.

The control board 133 inputs a sensed signal from the vacuum sensor 112 through an input terminal P2 and allows its built-in analog-digital (AD) signal converter to convert the sensed signal to a digital signal, thereby determining the vacuum state. The control board 133 outputs the determination of the vacuum state to the computer 150 to store it. In the drawings, a monitor, keyboard, and printer are denoted by reference numbers 151, 152, and 153, respectively. Although the embodiment of the present invention is implemented in such a way that the ultrasonic sensor 142 is installed to the autonomous roving vehicle 140, it may be modified such that ultrasonic sensor 142 could be attached to the packers 70.

Figure 4 is a cross-sectional view depicting a sewer pipe to which a watertight test for sewer pipes apparatus according to the present invention is applied, which is configured as follows.

An air pressure valve Vl for controlling a compressed air to inflate packers 70 is installed to an air injection pipe 82 connected to the output end of the compressor 120.

A vacuum valve V2 for controlling vacuum pressure of the sewer pipe 60 is installed to the evacuation pipe 74 that extends to the interior of the sewer pipe 60 through the packer 70, in which the sewer pipe 60 is communicated with the output port of the vacuum pump 110.

Based on respective predetermined setting values, the air pressrue valve Vl and vacuum valve V2 are automatically closed and opened according to the remote control of the control board 133 as shown in Figure 3.

The packer 70 is configured to include: an inflation member 80 shaped as a doughnut, for inflating and sealing the interior of the sewer pipe 60; a cylindrical inflation member fitting pipe 71 insertedly fitted into the inside diameter of the inflation member 80; an inside plate 72 that seals an inner end portion of the inflation member fitting pipe 71 and allows the evacuation pipe 74 to extend through the inside plate 72 and the inside diameter of the inflation member fixing pipe 71 to the interior of the sewer pipe 60; and an outside plate 73 that seals an outer end portion of the inflation member fitting pipe 71 and allows the evacuation pipe 74 to extend therethrough to the interior of the sewer pipe 60. The outside plate 73 has a diameter greater than the inside diameter of the sewer pipe 60. The outside plate 73 includes a fitting hole 77 into which an air injection nozzle 81 is fitted. The air injection nozzle 81 is coupled to an air injection pipe 82 such that air is injected into the inflation member 80.

The outside plate 73 includes a fastening bolt 75 at the center thereof through which the evacuation pipe 74 passes. As the fastening bolt 75 is coupled with a fastening nut 76, the evacuation pipe 74 is fixed to the outside plate 73. Although the present invention is embodied in the sewer pipe that allows water to flow in a gravity flow mode, it should be understood that it could be applied to a variety of pressure pipes, such as a water supply pipe. The outside plate 73 and inside plate 72 are fixedly or detachably coupled to the inflation member fitting plate 71 interposed therebetween, by welding or screw coupling.

After that, as shown in Figure 4, the packers 70 are installed to both ends of the sewer pipe 60, and then the air injection pipe 82 and the evacuation pipe 74 are installed thereto. It should be understood that the air injection pipe 82 and the evacuation pipe 74 may be previously assembled with packers 70, which is called an assembled product, such that the assembled product can be installed to the sewer pipe 60. On the other hand, before the packers 70 are installed to the sewer pipe 60, it is assumed that the autonomous roving vehicle 140, as shown in Figure 3, has been previously placed in the sewer pipe 60, and, at the same time, the take-up reel of the vehicle 140 has wound thereon the power cables 35, the image signal cable 136, and the sensor cable 137 whose other ends are outside of the pipe, while they are molded at the end of the sewer pipe 60.

Next, when the ignition switch SW of a user's vehicle is turned on, the engine 102 starts to operate through the spark plugs 103 of the engine driver 101 and transmits the output power to the engine shaft 104. The clutch 106 fixed to the vehicle frame 107 is operated manually or automatically to transmit the output power of the engine 102 to the compressor 120 and the vacuum pump 110 via the engine shaft 104. Here, the embodiment may be modified in such a way that the compressor 120 and the vacuum pump 110 are operated simultaneously or individually using an additional switch (not shown) .

When the compressor 120 creates compressed air, the air pressure valve Vl is opened (manually or automatically), so that the compressed air passes through the air injection pipe 82 and the air injection nozzle 81 and inflates the inflation member 80. The inflation member 80 is inflated to seal the sewer pipe 60 until the interior of the sewer pipe 60 is isolated from the external environment. The inflation pressure of the inflation member 80 can be set by the air pressure and time of supply the air, taking into account the diameter of the sewer pipe 60.

After the sewer pipe 60 has been sealed, the vacuum valve V2 is opened and the vacuum pump 11 evacuates air from the sewer pipe 60 until the vacuum sensor 112 senses a predetermined pressure in the sewer pipe 60. When receiving a vacuum pressure value (the degree of vacuum) sensed by the vacuum sensor 112, the control board 133 converts the vacuum pressure value to a digital value to output it to the computer 150 in real time. When the air is evacuated from the sewer pipe through the evacuation pipe 74 and thus the interior of the sewer pipe 60 becomes vacuum, the packer 70 is drawn into the interior of the sewer pipe 60 but the outside plate 73, whose diameter is greater than that of the sewer pipe 60, prevents the packer 70 from being drawn.

A user can view the degree of vacuum of the sewer pipe 60, on the monitor of the computer 150, through a search screen implemented by an application program. At the same time, the monitor displays the images shot by the CCTV camera 141 of the autonomous roving vehicle 140. That is, when the CCTV camera 141 shoots the images of the interior of the sewer pipe 60 and outputs the image signals to the computer, the image processing board of the computer converts the image signals into digital signals to store them and displays the images on the monitor 151. Therefore, the user can control the forward and backward movement of the autonomous roving vehicle 140 while viewing the images and the degree of vacuum of the interior of the sewer pipe 60.

A receiving unit of the ultrasonic sensor 142 detects ultrasonic waves periodically generated as the autonomous roving vehicle is traveling in the sewer pipe, and outputs the detected ultrasonic signals to an input port Pl of the control board 133.

For example, if the control board 133 receives an abnormal ultrasonic signal due to damage of the interior of the sewer pipe from the ultrasonic sensor 142 and determines whether exterior air enters the sewer pipe 60. In particular, the location of the damage can be checked through the CCTV camera 141. Therefore, the watertight test apparatus and method of the present invention can shorten test time of the sewer pipe since it does not need preparation of test water. Also, the watertight test apparatus and method of the present invention can check the watertightness of the sewer pipe based on change in the degree of vacuum or ultrasonic signals. Particularly, since the CCTV camera shows the location of the damage, the watertight test can be performed with high precision.

Embodiment

1. Specification

2. Evacuation Time Measurement: Vacuum Test based on Pipe Diameters To measure evacuation time of a pipe, the pipe to be tested is manufactured to have a variety of diameters. The pipe is prepared to be in a state where it allows a water head of Im to leak according to a conventional water head test, and then undergoes a vacuum test. After that, the evacuation time for each pipe is measured in a range of the conventional water head test. The measurement is shown in the following table. [Table 1]

* Dia: diameter; Dis: distance; VoI: volume; WT: watertight; Msmt measurement

Table 1 shows measurement results of watertight tests for vacuum sewer pipes

In the preferred embodiment of the present invention, the pipes in the range of 150-1,000mm are sealed by packers, based on the described above specification. But, if the sewer pipe 60 has an exceedingly high degree of vacuum (or a low vacuum pressure), the packers 70 sealing both ends of the sewer pipe 60 may be drawn into the interior of the sewer pipe 60. To prevent this, the outside plate 73 of each packer 70 is tightly coupled to the inflation member fitting plate 71 using a fastening bolt (or a supporting part) or welded to the inflation member fitting plate 71. A sewer pipe operating in a gravity flow mode must be maintained such that its vacuum pressure can be less than 380 torr, or a vacuum state of 50%. That is, since the lower the higher the degree of vacuum, the vacuum pressure cannot be less than 380 torr. It is preferable that pressure pipes, such as a water supply pipe, have a vacuum pressure of 1-379 torr. Since the gravity flow sewer pipe does not need such a high degree of vacuum, it has a vacuum pressure of 380-600 torr. Also, the pressure pipes have a vacuum pressure of 1-379 torr. Since the packers of each pipe undergo various pressures as described in the following table, they must be properly selected to endure a corresponding vacuum pressure. [Table 2]

[Industrial Applicability]

Since the watertight test apparatus and method according to the present invention create a vacuum in a pipe and test the watertightness of the vacuum pipe, test time, installation/removal time of the apparatus, test costs can be reduced, but test precision can be improved, in comparison to a conventional watertight test apparatus and method that fill a pipe with water or air, apply a high compression pressure to the pipe, and test the watertightness of the pipe. In addition, the test apparatus and method according to the present invention can test the watertightness of a variety of sewer pipes. Furthermore, the watertight test apparatus and method according to the present invention can test the watertightness of a pipe without using a commercial power supply or an electric generator, as is configured in such way that a vacuum pump and a compressor for inflating packers are driven by a rotational force from an engine of a vehicle, thereby performing the watertight test in a desert area or an interior.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[CLAIMS] [Claim 1]

A watertight test apparatus for testing a sewer pipe comprising: a vacuum pump for creating a vacuum in the sewer pipe, whose both ends are sealed by packers (70), through a vacuum pipe that extends through the packer (70) to the interior of the sewer pipe; a compressor for creating compressed air and inflating the packers, so that the packers can seal the inner walls of the sewer pipe; and a sensor for sensing leakage of air in the sewer pipe. [Claim 2]

The apparatus according to claim 1, wherein: the vacuum pump and the compressor are driven by a vehicle engine as the vacuum pump and the compressor receive power of the vehicle engine through pulleys; and the pulleys receive the power through an engine shaft and a clutch associated with the vehicle engine. [Claim 3]

The apparatus according to claim 1, wherein the sensor is installed to an autonomous roving vehicle traveling in the sewer pipe and generating a ultrasonic wave, and received the ultrasonic wave to read the leakage based on change in the ultrasonic wave. [Claim 4]

The apparatus according to claim 2, wherein: the compressor installs an air pressure valve (Vl) to its output side, the air pressure valve (Vl) controlling the compressed air flowing into the packers; and the vacuum pump installs a vacuum vale (V2) to its output side, the vacuum valve (V2) closing and opening a vacuum pressure pipe to control a vacuum pressure of the interior of the sewer pipe, and the vacuum pressure pipe extending through the packers to the interior of the sewer pipe, wherein the apparatus further comprises: a control board for automatically closing or opening the air pressure valve (Vl) and the vacuum valve (V2) based on predetermined values. [Claim 5]

The apparatus according to claim 4, wherein the control board outputs sensed values to an input/output unit of a computer through an output unit thereof, in real time. [Claim 6]

The apparatus according to claim 3, wherein: the autonomous roving vehicle receives output power to which an inverter converts AC power from a vehicle battery (Bl); and the autonomous roving vehicle is integrally installed with a take-up reel that winds or unwinds a power line of the inverter, and sense lines and image signal lines of the ultrasonic sensor. [Claim 7]

The apparatus according to claim 1, wherein the packer (70) comprises: an inflation member (80) shaped as a doughnut, for inflating and sealing the inside diameter of the sewer pipe 60; a cylindrical inflation member fitting pipe (71) insertedly fitted into the inside diameter of the inflation member (80); an inside plate (72) that seals an inner end portion of the inflation member fitting pipe (71) and allows the evacuation pipe (74) to extend through the inside plate (72) and the inside diameter of the inflation member fitting pipe (71) to the interior of the sewer pipe 60; and an outside plate (73) that seals an outer end portion of the inflation member fitting pipe (71) and allows the evacuation pipe (74) to extend through the outside plate (73) to the interior of the sewer pipe, wherein the outside plate (73) has a diameter greater than the inside diameter of the sewer pipe (60). [Claim 8]

A watertight test method for testing a sewer pipe comprising: sealing both ends of the sewer pipe and evacuating air to create a vacuum in the sewer pipe through a vacuum system; measuring time of evacuation, and closing a vacuum valve when the sewer pipe is reduced to a certain vacuum pressure; and monitoring variation in the vacuum pressure of the sewer pipe, and determining a watertight state of the sewer pipe based on the variation. [Claim 9]

A watertight test method for testing a sewer pipe comprising: installing watertight inflation members with packers, and installing vacuum valves for controlling a vacuum pressure of the sewer pipe; installing the packers with both ends of the sewer pipe, respectively, and placing an autonomous roving vehicle in the sewer pipe to which a watertight sensor is mounted; inflating the watertight inflation members, and operating the vacuum valves to create a vacuum in the sewer pipe; and reading watertight values based on variation in ultrasonic waves detected by the ultrasonic sensor or on variation in the vacuum pressure, applying the read watertight values to a computer through a control board, in real-time, and displaying the watertight state of the sewer pipe. [Claim 10]

The method according to claim 8 or 9, further comprising a vacuum sensor installed in the vicinity of the vacuum valve, wherein the control board controls the operations of the vacuum pump, based on a predetermined vacuum pressure, to prevent the sewer pipe from deforming.