The present invention relates to a method for manufacturing a pipe for a pipeline, which pipe can provide information for the condition of the pipeline continuously or periodically, and to such a pipe providing this kind of monitoring option.

There is generally a great and increasing need for water pipeline rehabilitations, especially in western countries, where the pipelines are often over 60 years old. Nowadays these renovation decisions are made according to the age and material of the pipes, and not the actual condition of the pipework, since this condition infor- mation is not available.

Further, the costs for fixing broken pipelines are much greater, both economically and timewise, than planned and scheduled maintenance and upkeep of pipelines based on actual condition data.

Also, the water usage is presently typically measured only in the place of water consumption, which leads to that in a water distribution network there are only few measuring points, which is not sufficient for an effective water leakage detection.

Thus, there is a need for an implementation or a solution for measuring liquid amounts passing through the pipeline, which can be utilized for collecting condition data of pipelines. Further, since the pipelines are often located underground, the collected data should also be easily accessible.

The present invention provides a solution for collecting data from water or liquid amounts passing in the pipeline, which solution is integrated in a pipe itself and can thus be easily placed anywhere on the pipeline. Further, the solution of the invention can also provide the data for analysis substantially continuously. In the method of the invention for manufacturing a pipe for a pipeline, wherein at least part of the pipe is manufactured by additive manufacturing process, at least one space for an ultrasonic transducer is formed inside the material of the pipe dur ing the additive manufacturing process, the additive manufacturing process is inter rupted before the said space is closed, the ultrasonic transducer is inserted in the said open space, and the additive manufacturing process for manufacturing the pipe is continued, which continued additive manufacturing process covers the said space. This way the ultrasonic transducer can be placed inside the material of the pipe without causing it to be excessively heated, and the proper positioning of the ultra sonic transducer in relation to the inner area of the pipe can be guaranteed.

In an embodiment of the method of the invention the space for the ultrasonic trans ducer is covered with a lid after inserting to the ultrasonic transducer and before continuing the additive manufacturing process. The lid is preferably made of a metal material, and may be manufactured from the same material as the pipe and simul taneously with the pipe with the same additive manufacturing process.

In an embodiment of the method of the invention two longitudinally displaced spaces are formed along the length of the pipe for two ultrasonic transducers. Alternatively, in this embodiment, the space for a second ultrasonic transducer can be formed as an open space in the end of the pipe, in the area of a pipe connection, so that the second space is closed when a next pipe is connected to the pipe with the trans ducers.

In an embodiment of the method of the invention at least one acoustic reflector is formed in the inner surface of the pipe with the additive manufacturing process of the pipe. Preferably the at least one acoustic reflector is formed in a recess on the inner surface of the pipe.

In an embodiment of the method of the invention the material of the pipe is metal, preferably steel, and more preferably AISI 316L steel.

In an embodiment of the method of the invention the additive manufacturing process is powder bed fusion process, such as direct metal laser sintering (DMLS), selective laser melting (SLM) or selective laser sintering (SLS).

The present invention also provides a pipe for a pipeline comprising an inner surface and an outer surface, and at least one ultrasonic transducer embedded inside the material of the pipe during the additive manufacturing process.

In an embodiment of the pipe of the invention the pipe comprises two ultrasonic transducers embedded inside the material of the pipe.

In an embodiment of the pipe of the invention the pipe comprises at least one acous tic reflector formed from the material of the pipe on the inner surface of the pipe. In this embodiment the at least one acoustic reflector is preferably located at least partially in a recess of the inner surface of the pipe. In an embodiment of the pipe of the invention the pipe comprises suitable data trans mitting means, such as a radio and an antenna, for transmitting the measurement data from the at least one ultrasonic transducer, and/or controlling means, such as a microcontroller unit (MCU), for controlling the at least one ultrasonic transducer. Further, the required wiring and electronic connections for these means are prefer ably integrated in the pipe.

More precisely the features defining a method in accordance with the present inven tion are presented in claim 1 , and the features defining a pipe of the invention are more precisely presented in claim 7. Dependent claims present advantageous fea tures and embodiments of the invention.

Exemplifying embodiment of the invention and its advantages are explained in greater detail below in the sense of example and with reference to accompanying drawing, which

Figure 1 shows schematically a cross-section of an embodiment of a pipeline part in accordance with the present invention.

In figure 1 is shown a DN75 tube for socket joint 1 which is manufactured with pow der bed fusion additive manufacturing process starting from the plane A and pro ceeding upwards. The material of the socket joint 1 is AISI 316L stainless steel.

During the additive manufacture process, when the process proceeds to plane B, the manufacturing process is interrupted, and an ultrasonic transducer 2 is inserted in a space formed inside the material wall of the manufactured socket joint 1 . After inserting and proper positioning of the ultrasonic transducer 2, which in this embod iment is a transmitter, the open place for the transducer is closed with a lid, and the additive manufacturing process is continued until plane C is reached.

At the plane C the additive manufacturing process in interrupted again, and second ultrasonic transducer 3, which in this embodiment in a receiver, is inserted in a space formed inside the material wall of the manufactured socket joint 1 . After inserting and proper positioning of the second ultrasonic transducer 3, which in this embodi ment is a transmitter, the open place for the transducer is closed with a lid, and the additive manufacturing process is continued until the whole socket joint 1 in ready.

The lids used for closing the formed open spaces within the walls of the socket joint 1 can be made from suitable metal plates, for example. The lids may also be man ufactured simultaneously with the socket joint 1 and with the same manufacturing process, and then added to the socket joint during the interruption of the manufac turing process. The function of the lids is to provide suitable surface for the contin ued powder bed fusion process, so the material of the lids needs to be able to with stand the required temperatures for this process. Further insulation material may be inserted into the formed spaces together with the ultrasonic transducers for protect ing and/or properly positioning the transducers within the formed space, for exam ple.

During the additive manufacturing process of the socket join 1 , three acoustic re flectors 4a-4c are formed in the inner surface of the socket joint. These reflectors 4a-4c are in this embodiment located in recesses formed in the inner surface of the socket joint 1 . This way the reflectors do not significantly hinder the fluid flow inside the socket joint.

Further, the acoustic reflectors 4a-4c do not require any further finishing actions after the additive manufacturing process, since the surface quality achieved during this manufacturing process is sufficient. Also, at their simplest form the acoustic reflectors can be suitably directed and positioned surfaces, even though they are shown in the figures as separate structural entities.

With the acoustic reflectors 4a-4c the length of the ultrasonic measurement beam 5 from the transmitter 2 to the receiver 3 is extended so that the accuracy of the ultra sonic measurement is improved.

In relation to the embodiment shown in figure 1 and the measurement beam 5, it is to be noted, that the places of the ultrasonic transmitter 2 and receiver 3 can be changed so that the measurement beam 5 proceeds to opposite direction. Further, the ultrasonic transmitter 2 and receiver 3 can both be replaced with ultrasonic trans ceivers, wherein both transceivers operate both as a transmitter and as a receiver, so that the measurement beam 5 is bounced between the transceivers, for example.

In the present invention ultrasonic technology is applied for the measurement of fluid, such as gas, liquid or combination of these, flowing through the socket joint 1 . The basic principle of the measurement is always the same, i.e. the propagation of ultrasonic through fluid in motion. The measurement can be realized in many differ ent ways, which in particular are based on: Doppler effect, ultrasonic propagation velocity differences, ultrasonic beam drift and cross correlation technics. The transit time flowmeters can be divided into two different groups: direct transit time and dif ferential transit time meters. For example, the flow velocity in time of flight method is where c = sound velocity in medium, At = time of flight time difference in flow against downstream and upstream ultrasonic pulse, and L = length of ultrasonic pulse path. In the ultrasonic measurement the scattering can be used to define turbidity of the measured fluid, the attenuation can be used to define possible accumulation of dirt and other contaminants on the inner surface of the measurement area over time, and absolute travel time can be used to define the temperature of the fluid, for ex ample. The finished socket joint 1 also preferably comprises an antenna 6 for transmitting the collected measurement results for further analysis. The antenna 6 is preferably connected to the socket joint 1 with wiring 7, so that it can be located at a distance from the actual pipeline, such as on ground surface in cases where the pipeline is dug underground for example, so that the data can be forwarded efficiently. Further, the required power source (not shown) for the ultrasonic transducers 2 and 3 is also connected to the socket join 1 via wiring, so that it is easily accessible and replace able without actual access to the pipeline itself.

The other required electronics for carrying out the measurements and connected to the ultrasonic transducers 2 and 3, such as the measurement electronics and mi- crocontroller unit (MCU) are not shown in the embodiment of figure 1 , but these can be integrated in the socket joint 1 itself (with suitably formed channel and spaces), on the outer surface of the socket joint, close to the socket joint 1 , or in with the antenna 6, for example. The cable length in between the socket joint and other re quired electronics should be short enough (approximately under 2 meters), so that this distance does not affect the actual measurement and the related processing phase negatively.

The specific exemplifying embodiments of the invention shown in figures and dis cussed above should not be construed as limiting. A person skilled in the art can amend and modify the embodiments described in many evident ways within the scope of the attached claims. Thus, the invention is not limited merely to the em bodiments described above.