Excavator height measurement, protects power supplies, protects drivers
In a change from their more usual applications controlling and measuring flow and level of all sorts of materials, Pulsar Process Measurement Ltd have supplied non-contacting ultrasonic level measurement to the North Level District Internal Drainage Board to measure the height of the arm of the jib arms mounted on hydraulic excavators used to keep the drainage channels clear.
As the excavators work along the drains, cutting weeds , there is a danger that they can hit or even pull down overhead power lines. This is clearly dangerous to the driver, but can also interrupt power supplies to homes and businesses or set fields of stubble alight. The Health and Safety Executive (HSE) have identified this as an issue and have a multitude of publications detailing safe working methods. At the North Level District Internal Drainage Board, the written procedures to avoid this issue include the instruction to drivers to maintain a 2m clearance below power cables at all times. The driver knows the height of the power cables from a set of tables, and can set a maximum height for the cutting arm.
In order to set the maximum height accurately, the driver needs to know the height of the jib arm above very variable ground levels. This is where the Pulsar unit comes in.
Pulsar supplied blackbox non-contacting ultrasonic equipment consisting of a dB10 transducer mounted on the cutter arm connecting to a blackbox unit with a level display in the cab. The transducer is mounted on bearings that allow it to rotate freely so the transducer continuously faces the ground. It emits ultrasonic pulses which reflect from the ground, the time taken for the echo to return to the transducer face being converted to a distance. The driver can then read off the measurement from the display in the cab and limit the jib arm height accordingly. The blackbox unit has provided reliable measurement on all sorts of surfaces, including ploughed fields, riverbanks and more, and has helped the North Level District Internal Drainage Board to work more safely.