Design and Development of a Battery Powered Electrofusion Welding System for Optical Fiber Microducts

Abstract

At present, optical fiber microducts are coupled together by mechanical types of joints. Mechanical joints are thick, require a large space, and reduce the installation distance in multi-microduct installation. They may leak or explode in the blown fiber installation process. Mechanical joints are subjected to time dependent deterioration under long service times beneath the earth's surface. It may start with a small leakage, followed by damage due to water freezing inside the optical fiber microduct. Optical fiber microducts are made up of high-density polyethylene, which is considered most suitable for thermoelectric welding. For thermoelectric welding of two optical fiber microducts, the welding time should be one second, and should not cause any damage to the inner structure of the microducts that are being coupled. To fulfill these requirements, an LTspice simulation model for the welding system was developed and validated. The developed LTspice model has two parts. The first part models the power input to joule heating wire and the second part models the heat propagation inside the different layers of the optical fiber microduct and surrounding joint by using electro-thermal analogy. In order to validate the simulation results, a battery powered prototype welding system was developed and tested. The prototype welding system consists of a custom-built electrofusion joint and a controller board. A 40 volt 4 ampere-hour Li-Ion battery was used to power the complete system. The power drawn from the battery was controlled by charging and discharging of a capacitor bank, which makes sure that the battery is not overloaded. After successful welding, a pull strength test and an air pressure leakage test were performed to ensure that the welded joints met the requirements set by the mechanical joints. The results show that this new kind of joint and welding system can effectively replace mechanical joints in future optical fiber duct installations.

Battery Powered Inductive Welding System for Electrofusion Joints in Optical Fiber Microducts

“…The calculated thermal parameters were connected in a Cauer thermal model configuration, where each RC node represents the temperature at the corresponding outer layer of the LDPE shell [15]. The developed LTspice electrothermal model was utilized to develop a battery powered electrofusion welding system with a resistive type optical fiber electrofusion joint (ROFEF) joint [3]. In Akram et al [3], it was shown that the battery powered electrofusion welding of two optical fiber microducts could be achieved with a power input of 167.74 joules, and it could withstand 300 newtons pull strength and 10 bars of air pressure, showing no signs of air leakage and water seepage.…”

“…The developed LTspice electrothermal model was utilized to develop a battery powered electrofusion welding system with a resistive type optical fiber electrofusion joint (ROFEF) joint [3]. In Akram et al [3], it was shown that the battery powered electrofusion welding of two optical fiber microducts could be achieved with a power input of 167.74 joules, and it could withstand 300 newtons pull strength and 10 bars of air pressure, showing no signs of air leakage and water seepage. The developed LTspice welding model [3] is reproduced here in Figure 3a.…”

“…In Akram et al [3], it was shown that the battery powered electrofusion welding of two optical fiber microducts could be achieved with a power input of 167.74 joules, and it could withstand 300 newtons pull strength and 10 bars of air pressure, showing no signs of air leakage and water seepage. The developed LTspice welding model [3] is reproduced here in Figure 3a. The model utilized a capacitor bank of 0.056 farads and a PWM charge-discharge cycle to power the ROFEF joint.…”

“…The air pressure sustaining capability of mechanical joints is principally dependent upon O-rings. Experience has shown that the mechanical joints leak at air pressures lower than 1 bar [3]. The normal installation air pressure in blown optical fiber is 15 bars for a 14.0 mm microduct.…”

Advances in Tapered Optical Fiber Sensor Structures: From Conventional to Novel and Emerging

“…Subsequently, fiber-optic sensing came into being. Compared with traditional electrical sensors, fiber-optic sensing uses optical signals as the modulation and transmission carrier, which allows it to have many unique advantages [ 1 , 2 , 3 , 4 ], such as strong resistance to electromagnetic interference in the transmission process, thus allowing it to play a very significant role in the power system [ 5 , 6 ], and strong corrosion resistance, which can be measured for highly corrosive analytes [ 7 ], as it has a compact structure that can be fabricated according to the needs of the size of very small fiber optic sensors [ 8 ]. Simultaneously, several studies have highlighted the advantages of simple fiber optic materials, cost-effectiveness, and broad scale utilization [ 9 , 10 ].…”