ELE

Design and Kinematics analysis of Underwater

Guillotine Saw for Oil&Gas Pipe

1 2

Gong haixia , Zhao jie , Meng qingxin2 , Li peng1,2 and Song Liang3

1,21

School of Mechatronics Engineering , Harbin Institute of Technology, 150001, China

College of Mechanical and Electrical Engineering, Harbin Engineering University, 150001, China 3

Harbin Huaxia Institute of Computer Technology, 150025, China

Abstract- Oil or gas was transferred to one place by pipeline

II. WORKING PRINCIPLE AND STRUCTURE DESIGN after exploitation of ocean oil&gas resources. When an old pipeline

The guillotine saw was always used in offshore pipeline was leaking, it must be repaired. The guillotine saw is a necessary

tool for repairing underwater oil&gas pipes, and is used to cut off projects, such as laying and maintenance of pipe in the seabed. damaged offshore pipeline. It was composed of sine cutting Sketch of underwater working of the guillotine saw was shown mechanism, eccentric cam mechanism and spiral feed in Figure 2.1.

Underwater working principle: divers carried out installation mechanism. According to its technique process of cutting pipe,

kinematics model of the guillotine saw was proposed. The rotation of the guillotine saw in sea. They linked the adjustable chain and center of principal axis acted as center of the coordinates, the then clasped it in the pipeline, then adjusted the tensional nut to whole kinematics model was deeply discussed and its simulation tighten the chain so that the saw body could be fixed in the analyses were finished, such as movement contrail and cutting pipeline to avoid the cutting process was unsteady. After that, state of the tool. Total resultant movement was validated by the divers jointed the source of hydraulic oil through quick simulation and underwater experiment. Analytical results showed connector and informed the operator on board to run the that there were optimized parameters: cutting velocity v=314 machine. The main motor droved the saw to move back and mm/s, feed velocity vj=12.5 mm/min, height of lifting the saw blade forth, and the feed motor droved the screw nut to move in backhaul e=8~10 mm, and e is determinated by synthetical downward. After fast-forward moving and working feed, the factors of movement. Synchronously, experiment shows that work special structure enabled the saw blade to be lifted upgrade of the guillotine saw is reliable under the influence of current in automatically after each cutting return, to extend the service life shallow sea. So the kinematics model is applicable for offshore of cutting tools. In the feed process, the guillotine saw could pipeline service. The guillotine saw can offer a service measure of adjust cutting speed and feed rate automatically through control

system. It first adjusted main cutting rate, and then the feed rate. underwater pipe for oil and gas transporting successfully.

I. INTRODUCTION

In recent years, in order to meet the needs of exploitation of

marine resources specially oil&gas, transportation, design, construction, operating processes and work technology of some devices have been get a long-term development. These devices will be used in various ocean engineering about exploration, exploitation, detecting and repairing of oil&gas or other mineral resources. But in comparison with foreign relevant technology there is still a gap. A specialized guillotine saw is developed in order to break the monopoly of foreign companies in the repairing pipes engineering. The purpose is to cut off the damaged pipe at the scene to replace the new pipe section.

The underwater guillotine saw belongs to the complex structure. Most of the equipments come from overseas company. There is still a lack of complete research in our country. The paper established the kinematical equation of the cutting process of the guillotine saw and achieved a better kinematics analysis, and simulated the results of analysis and validated the underwater experiment. The saw offered a repairing measure of offshore pipeline for oil and gas transporting successfully.

According to the data transmitted from the sensor we determined whether or not that cutting process was normal. We

also could adjust the two rates.

1. support vessel 2、3. controlling system 4. hydraulic system 5. the guillotine saw 6. seabed

7. sea level 8. benthonic oil & gas pipe 9. transport cable and hydraulic oil pipe Fig.2.1 Sketch of underwater working of guillotine saw