Design & Development of Underwater Load Cell for Deep Sea Applications

Load cells are the devices which can be used for different types of weighing applications. This paper presents the design of a pressure compensated strain gauge based load cell which can be operated for various deep sea applications. This load cell is a transducer that is used to convert a force or load into electrical signal. This conversion is indirect and happens in two stages. Through a mechanical arrangement, the force is sensed which deforms the strain gauge and the deformation (strain) is measured as an electrical signal, because the strain changes the effective electrical resistance of the wire. This load cell is designed with full Wheatstone bridge configuration for detecting both tension and compression load and also for ensuring better accuracy. The electrical signal output is typically of the order of a few mill volts and needs conditioning with necessary signal processing circuitry before it can be used further. Finally the device needs to be enclosed inside a pressure compensated enclosure which can withstand 600 bar outside pressure. The device is mainly designed considering the Indian Ocean parameters and it will work at a depth of 6000 meters under water.