"Brush & Flush" spray headers, designed decades ago for pulp and paper mills. In paper mills the push towards recycling resulted in mills trying to spray reclaimed "industrial" and "white" water. As we know, particles and spray nozzles don't mix - the potential for plugging nozzles and getting growth inside the headers is enormous. It used to be that the only solution was to strain the fluid prior to re-spraying it by installing sophisticated strainer systems.

There is nothing wrong with strainers, But when one takes a systems approach and chooses the right nozzle header it minimizes the amount of straining required. Strainers with larger mesh openings do not need to be maintained as often.

So how do they work? To begin with the nozzles themselves are very different for a typical flat spray nozzle. Most flat sprays have a "V" milled across a hole and it's the "V" that creates the flat spray pattern. The resulting hole is elliptical in shape and is usually described as being in the shape of a "cats eye".

Here's how a nozzle usually plugs-up, even when the fluid is filtered:

Particles in the fluid stream tend to settle in-between nozzle ports because these are areas of lower velocity and turbulence. Eventually even small particles that would pass through an orifice will clump together until they gain enough mass to "roll" into the orifice. Since the free passage is less towards the slit ends of the elliptically shaped orifice, that's usually were a clog begins. From there the clog grows, eventually blocking the entire nozzle. And the process continues, as each nozzle plugs, the solids in the fluid become concentrated and the other nozzles plug-up even faster in succession. Straining or filtering the fluid helps matters, but that's often not practical for mills that require large volumes of fluid.

Our nozzles have a "reverse orifice", which means that the elliptically shaped orifice protrudes into the header itself. Located inside the spray header is a stainless steel brush rod assembly, which runs the full length of the header (covering both the nozzles and low-velocity areas between nozzle ports). The brush rod assembly is attached to a valve and hand wheel (which can be motor driven as an option). When the hand wheel is rotated the stainless steel brushes scrape against the interior walls of the shower pipe and across the orifices themselves, dislodging any material inside. It takes about 3 turns of the hand wheel to completely unseat the internal valve in the shower pipe. When fully opened about 20% of the total header flow rate bypasses through the valve (the path of least resistance), and all the particles inside are also "flushed" through the valve.

By observing the spray header one can usually see if the nozzles are totally or partially plugged. A quick and simple rotation of the hand wheel cleans the pipe and nozzles, flushing the particles through the discharge valve. This is a safe, efficient and effective way to clean your nozzles while you keep spraying. Special "reverse orifice nozzle" allows the internal brush to sweep through the orifice and dislodge foreign material that may be impeding the spray. The spray tips are self-aligning to ensure proper overlap and coverage every time.