Abstract: A centraliser comprises longitudinally spaced collars connected by a plurality of springs, each of the springs comprising two or more bow sections.

Abstract: A drainage collection box device for automatically removing leaves and other debris from a collection box of a drainage system. The drainage collection box device includes a container having a base, an open upper end, one or more sidewalls, and one or more openings disposed on the sidewalls. Each opening of the container can be connected to a pipe of a drainage system, wherein water and debris travel into the container therefrom. The device further includes a lid pivotally secured to the upper end of the container and a pair of baffles disposed on the sides of the lid. As the water level rises to the top of the container, the pressure from the rising water and debris push the lid to an open configuration, wherein the baffles direct the water and debris to flow out of the front upper end of the container.

Abstract: A pressure relief bursting disc has a flange portion, a sloping portion interior of the flange portion and a dished portion interior of the sloping portion. The sloping portion has its wider end joined to the flange portion and slopes up from the flange portion in a first direction and is joined at its narrower end directly to the dished portion. The dished portion has its concave side facing in the first direction. In use pressure is applied to the concave side of the dished portion. The disc has a line of weakness, in the sloping portion. This shape achieves reliability of the burst strength, because the sloping portion buckles at the burst strength.

Abstract: A pressure relief bursting disc has a flange portion, a sloping portion interior of the flange portion and a dished portion interior of the sloping portion. The sloping portion has its wider end joined to the flange portion and slopes up from the flange portion in a first direction and is joined at its narrower end directly to the dished portion. The dished portion has its concave side facing in the first direction. In use pressure is applied to the concave side of the dished portion. The disc has a line of weakness, in the sloping portion. This shape achieves reliability of the burst strength, because the sloping portion buckles at the burst strength.