Abstract: A duct coupling system includes a first duct with a perimeter attached to a compliant sealing gasket and a second duct with a perimeter attached to an annular component sized to interface with a seat of the compliant sealing gasket. The compliant sealing gasket can be selectively tightened around the perimeter of the first duct by engaging a tightening mechanism of a clamp to selectively tension a cable with opposing first and second end portions attached to the clamp and a longitudinal central portion encircling a perimeter of the compliant sealing gasket. Tensioning of the cable causes circumferential compression of the compliant sealing gasket and forms a seal between the first duct and the second duct.

Abstract: Gas monitoring apparatus comprises a sensor module and an associated display module which can be physically connected together or separated. The sensor module contains gas sensors and is used to detect the concentration of gas, for example in a mine working. The sensor module transmits readings wirelessly to the display module, which includes a display to show the reading. Each sensor unit can communicate with multiple display units and vice versa.