Development of Gas Detection Device for Riser Inspection

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1 Development of Gas Detection Device for Riser Inspection WONG Kam-Kuen, Theo Hong Kong and China Gas Company Limited

2 Abstract The Hong Kong and China Gas Company Limited (Towngas) currently has over 1.86 million residential and commercial customers. We provide gas production, distribution and utilization services in Hong Kong. In order to maintain a reliable and safe supply of energy, we provide our customers with regular safety inspection on the gas service pipe system. Gas service pipe system usually consists of a main service riser erected outside the building with horizontal laterals pass through the façade of building, which feed Towngas to the flats of individual customers. In order to perform a full inspection on the service riser, we have developed a Quadcopter for inspecting the riser along external wall. This device is initially set on a landing base then it goes up along the service riser to perform the full inspection. Some constraints on the equipment set up, however, are identified when the Quadcopter goes into operation. To tackle such problem, a special gas detection device is developed. This device consists of a laser methane gun (Gas Detector) and camera, which can inspect the service riser along the external wall. With the development of this gas detection device, it simplifies the inspection flow as well as improves the inspection rate of gas service riser. 2

3 Contents 0. List of Figures Introduction Objectives Research Approach Plan-Phase Do-Phase Devices Serves for Gas Service Riser Inspection Devices Serves for Equipment Support Devices Serves for Safety Enhancement Check-Phase Act-Phase Project Benefits Conclusion References

4 0. List of Figures Figure 1 Building with Platform p.5 Figure 2 Building with Narrow Lightwell p.5 Figure 3 Fishing p.6 Figure 4 Screw Clamp p.7 Figure 5 Pulley System p.7 Figure 6 Flat Antenna p.8 Figure 7 Position for the 2 Flat Antennas p.8 Figure 8 Point Antenna p.8 Figure 9 New Position for the Antenna p.8 Figure 10 Extra Weight p.9 Figure 11 Newly Developed Gas Detection Device p.10 4

1. Introduction In order to perform a full inspection to the gas service risers, Towngas has developed a Quadcopter for inspecting the riser along external wall.

However, it is found that there are buildings with podiums, where the landing base cannot be set for the Quadcopter. Also, some buildings with special architecture feature (e.g. narrow lightwell) cause insufficient light to deploy Quadcopter for capturing the riser image.

5 1. Introduction In order to perform a full inspection to the gas service risers, Towngas has developed a Quadcopter for inspecting the riser along external wall. This device is initially set on a landing base then it goes up along the gas service risers and checks its condition. However, it is found that there are buildings with podiums, where the landing base cannot be set for the Quadcopter. Also, some buildings with special architecture feature (e.g. narrow lightwell) cause insufficient light to deploy Quadcopter for capturing the riser image. Figure1 Building with Platform Figure2 Building with Narrow Lightwell 2. Objectives The objective of this project is to develop a device, which enable us to conduct gas service riser inspection with a Simplified equipment setting Minimal disturbance to customer Reduced risk of working at height on scaffolding 5

3. Research Approach To tackle the identified problem, the plan-do-check-act (PDCA) model (Tague, 2004) is adopted. 4. To implement the newly developed solution 1.

Plan-Phase To plan for the solution, concept design and factors consideration are the critical parts to concern.

6 3. Research Approach To tackle the identified problem, the plan-do-check-act (PDCA) model (Tague, 2004) is adopted. 4. To implement the newly developed solution 1. To come up with the design concept and considerations 3. To conduct field test and evaluate the solution performance 2. To prototype and manufacture the designed solution 4. Plan-Phase To plan for the solution, concept design and factors consideration are the critical parts to concern. With reference to fishing (please see Figure 3), rope and pulley are used for hanging and transporting materials. Figure3 Fishing By modifying this concept, gas service riser inspection can actually be conducted by hanging an inspection device and lowering it from the building top to check the risers condition. In this sense, a landing-base is no longer needed in the equipment setting but a fixed-support has to be designed for holding the inspection device. Added to that, the designed device should be equipped with the functions of Methane Detection and Image Capture, which ensure the gas service risers are neither in gas leakage condition nor serious corrosion. On the other hand, safety is the most concerned factor in this solution so Proximity Detection and Emergency Control should also be embedded in the design. 6

5. Do-Phase After coming up with the design concept and considerations, the prototyping approach is to integrate several devices into one total solution, where these devices are used for Gas Service

1 Devices Serves for Gas Service Riser Inspection Firstly, a laser methane gun is set as the main body, where its principle is to emit a laser at particular wavelengths and analyse the reflected

7 5. Do-Phase After coming up with the design concept and considerations, the prototyping approach is to integrate several devices into one total solution, where these devices are used for Gas Service Riser Inspection, Equipment Support and Safety Enhancement. 5.1 Devices Serves for Gas Service Riser Inspection Firstly, a laser methane gun is set as the main body, where its principle is to emit a laser at particular wavelengths and analyse the reflected light to determine the amount of methane in the exposed environment (Tokyo Gas Engineering Co., 2013). On top of the laser methane gun, a high-digital camera with LED panel is located to capture the real-time image of gas service risers and the reading from laser methane gun. This visualizes the riser s corrosion status and gas leakage condition. 5.2 Devices Serves for Equipment Support Since the integrated device has to be hanged from building top, a fixture with pulley system is deployed. For the fixture, a screw clamp (please see figure 4), which can withstand a 20 kg object, is mounted on the rooftop wall. Then, a system with 5 pulleys (please see figure 5) is designed to convey the gas detection device, where a 7x7 Grade 304 stainless steel rope (Ben-Mor, 2017) is connected. Since the minimum breaking strength (MBS) of the Grade 304 stainless steel is 120 lb. (Ben-Mor, 2017), which is equivalent to 54.4 kg, it is believed that the pulley system and screw clamp are sufficient in withstanding the weight of the newly developed device (i.e. 6 kg). On the other hand, as the newly developed device may shake under wind blows, a stabilizer is used for retaining the camera s position. Should a wide angle image needed, the stabilizer can rotate for 360 o with the use of remote control. Figure 4 Screw Clamp Figure 5 Pulley System 7

This allows the user to pause the gas service riser inspection when encountering any foreseeable risks.

8 5.3 Devices Serves for Safety Enhancement To reinforce the safe use of the gas detection device, a proximity sensor is placed. Hence, the inspector would stop its motion, when it detects any obstacles beneath 1 meter from the sensor. For the case of manual re-set and control, the device is equipped with an emergency stop. This allows the user to pause the gas service riser inspection when encountering any foreseeable risks. Most importantly, the newly developed gas detection device has to be certified by a competence person. This is because the device is regarded as a lifting appliance so the Hong Kong law of factories and industrial undertakings (lifting appliances and lifting gear) regulations (Cap. 59, section 7) is applicable in this case. 6. Check-Phase To evaluate if the device fulfils the design purpose, 5 times of field test have been carried. During the field test, it is found that the service riser image may not be able to obtain sometimes. The reason may be contributed from the position that the antenna is located. Originally, two flat antennas (please see Figure 6) are put into two distinct positions, where the signal emitter cannot reach its receiver (please see figure 7). Figure 6 Flat Antenna Figure 7 Position for the 2 Flat Antennas To resolve the identified problem, one of the flat antennas is replaced with a point antenna (please see Figure 8) so the signal emitted is more disperse. Also, the two antennas are put into a near position. Hence, these two modifications may increase the chance for signal transmission. Figure 8 Point Antenna Figure 9 New Position for the Antennas 8

Apart from that, an extra weight of 4 kg (please see Figure 10) is added, where the purpose is to coincide the centre of gravity and centre of rotation and this stabilize the movement (N.A.S.

9 Apart from that, an extra weight of 4 kg (please see Figure 10) is added, where the purpose is to coincide the centre of gravity and centre of rotation and this stabilize the movement (N.A.S.A, 2015) of the device. Extra Weight Figure 10 Extra Weight 7. Act-Phase After improving the equipment set up, the image transmission problem is tackled. Therefore, an implementation plan has been set to put the gas detection device into field application. In general, the implementation plan has been divided into 3 phases including field test, on-site training and full deployment. For the 1 st phase & 2 nd phase, it has been carried in Quarter 3 and Quarter 4 of Year 2017 respectively, while the 3 rd phase is currently in progress. 8. Project Benefits Upon the completion of this project, it is believed that the newly developed gas detection device can further enhance occupational safety to front-line staff since it minimizes the chance of working at height on scaffolding. In second place, the risk of gas leakage in public should be reduced. This is because the device enables Towngas to conduct more inspections, especially to those buildings with inaccessible podium and narrow lightwell. With the use of newly developed device, the gas service riser inspection can be conducted without accessing every household. In this sense, the disturbance to customer can be minimized, which further enhances customer satisfaction. 9

10 Lastly, the development of this device promotes the corporate image on safety awareness and technological advancement because it tells the public that Towngas does put an effort in manifesting the corporate mission of providing our customers with a safe, reliable supply of energy and the caring, competent and efficient service they expect, while working to preserve, protect and improve our environment. 9. Conclusion To sum up, the development gas detection device for riser inspection replenishes the constraints of using Smart Quadcopter, where a landing base is no longer needed and the gas service riser inspection can be conducted in narrow lighwell. More than the that, the Plan-Do-Check-Act (PDCA) approach has be adopted, while 5 times of field test have been conducted to evaluate if the device fulfils the design purposes. After modifying the antenna for a better image signal transmission, the newly developed gas detection device is now at the stage of full implementation. Upon the full implementation, it is expected that more inspection can be carried without the use of scaffolding in high ground. Hence, the safety to front-line staff can be reinforced, while the public risk of encountering gas leakage from gas service riser can also be minimized. Figure 11 Newly Developed Gas Detection Device 10

11 10. References N. R. Tague, (2004), The Quality Toolbox ASQ Quality Press, 2 nd Edition, p Ben-mor, (2017), Stainless Steel 304 Cable, 7x7, Product Catalogue, Retrieved February 18, 2018 from HKSAR Government, (1974), Factories and Industrial Undertakings (Lifting Appliances and Lifting Gear) Regulations, Cap. 59, Section 7, Hong Kong Laws N.A.S.A (2015) Centre of Gravity cg, Retrieved February 18, 2018 from Tokyo Gas Engineering Solutions Co. Ltd, (2013), SA3C50A Laser Methane Mini-G Operation Manual, Tokyo Gas Engineering Solutions Co. Ltd, 2 nd Edition, p.2 11

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