Spray bar coverage width, pump rating and nozzle layout for road sprinkling and site damping — and how the duty cycle decides which configuration you order.
A spray bar's job is to lay an even film across a defined width in one pass. Two things decide whether it does.
Nozzle spacing and pattern. Nozzles are set so that adjacent fans overlap. Too little overlap and you get dry stripes that dust off first; too much and you use more water than the surface can absorb, which puddles and then makes the road slippery rather than damp.
Bar height and angle. The same nozzle set at a different height gives a different width and a different droplet arrival. Move the bar and the coverage changes, which is why the bar arrangement is specified rather than adjusted on site.
We do not publish a coverage width figure for this line. The bar, the pump and the nozzle set are configured per order, and quoting a width before the configuration exists would be a number without a vehicle behind it.
Pump rating is set by how fast you need to empty the tank, not by how big the tank is.
A vehicle laying water continuously along a haul road empties steadily and wants a pump matched to a sustained flow. A vehicle doing intermittent damping at a working face spends most of its time idle and needs pressure available on demand rather than sustained volume. A washing duty wants pressure above all, because there the water is doing mechanical work.
These are three different pump specifications on what looks like the same vehicle. The duty cycle has to come before the pump.
Street washing is a municipal duty on a made surface. It wants pressure, a nozzle arrangement aimed at the gutter line and the road edge, and usually a night shift because that is when traffic is light. Noise matters, because there are residents.
Haul road damping is an industrial duty on an unmade surface. It wants volume, wide coverage and a chassis that copes with the road it is treating. Nobody cares about noise; everybody cares about how many passes per hour the vehicle sustains.
A vehicle built for one will do the other badly. If your duty is actually both — municipalities with unpaved outskirts are the common case — say so at the start, so the compromise is made deliberately rather than by accident.
Four things get a sprinkling configuration specified: the surface you are treating, how many kilometres or square metres per shift, where the water comes from and how far away it is, and whether the work is on a public road or inside a site.
Those four settle the pump, the bar, the tank and the chassis between them.
