The driving head prevents damage to the top of the female thread and solid copper earth rod when driving into the ground. These reusable Wallis screw heads are suitable for driving earth rods manually or with an electric hammer. The driving head is screwed into a threaded joint to allow the rod to be pushed deeper.
A common misconception among designers of stormwater treatment plants is to use the driving head of rise (Δz), which is the physical descent between the inlet and outlet pipes, as the total driving head, rather than hydraulic descent between upstream and downstream water levels. . Complete and direct the head (Δh).
This relationship between the elevation driving head (Δz) and the driving head (Δh) can be further explained in Figure 1 below. The physical pressure difference (Δz) between the inlet and outlet pipe slabs is shown as 240mm and the drive head (Δh) at maximum handling peak flow is shown as 750mm between the exit slab and the outsole of the diversion. In this configuration, the minimum position where the inlet pipe can overflow the raw water upwards is 510 mm (Δh – Δz).