SPRAY NOZZLE SYSTEMS FOR PRETREATMENT TUNNELS

Each component of the quick change system is discussed in the relevant "nozzle designs" section available through the black menu to the left.

Pre-treatment tunnels involve a series of stations that spray various chemicals. Some of these chemicals, such as phosphates used for anti-rust conversion coating, are specifically chosen for their ability to react with metals. The purpose of the phosphate spray is to induce a reaction on the surface of the metal being sprayed to form a corrosion-resistant film. Spraying phosphates through metal nozzles can be dangerous, as most metals are susceptible to the actions of phosphate. While there are metals that are resistant to phosphate, they tend to be more expensive, and as pre-treatment plants operate at temperatures below 100 degrees Celsius, plastics such as glass-filled polypropylene are usually the more cost-effective material choice.

The chemicals used in the pre-treatment process are often expensive, with their cost exceeding that of the nozzles used to spray them. An efficient spray system that delivers the correct amount of spray to the right area is crucial to a well-run pre-treatment line.

Designing the tunnel to spray only in the desired areas can be challenging, and achieving the optimal setup often involves trial and error. Numerous minor adjustments need to be made to the nozzle angles, spray direction, or individual nozzles, as well as the positioning of nozzles on the pipelines. This can be a time-consuming process, especially when different products are being treated in the same tunnel.

Over time, all nozzles will eventually wear out or become clogged. It is strongly recommended to regularly clean and check for wear, as worn nozzles are often the root cause of insufficient spraying. Given that the cost of chemicals and water usually exceeds that of the nozzle, it may not be cost-effective to avoid replacing worn nozzles. Although replacing nozzles for cleaning and inspection can cause downtime, particularly for a large pre-treatment line with 1,000 nozzles, there are solutions to speed up this process.

Even slight wear or blockage can alter the spray pattern, as nozzles work by forcing fluid through a precisely machined opening. The shape of the opening determines the spray pattern and angle of the liquid. Even a small amount of particle buildup can significantly alter the resulting pattern, which can lead to areas being missed or undertreated, over-treatment of certain areas, or chemicals being sprayed at an incorrect angle. All of these can adversely affect the quality of the process and ultimately cost money.

Designing the tunnel to spray only in the necessary areas can be challenging, and the optimal setup often requires trial and error. Minor adjustments to nozzle angles, spray points, individual nozzles, and nozzle positioning on pipelines are often necessary, and this can be a time-consuming process. The challenge is compounded when multiple items are being treated in the same tunnel.

Despite the compelling case for regular maintenance, why do nozzles often go uncleaned for extended periods? The answer lies in the significant downtime required to remove, clean, and reinstall the potentially thousands of nozzles in a pre-treatment line. This downtime carries a cost, and management often perceives the cost of downtime to be higher than the cost of poor spraying.

Furthermore, nozzle maintenance is an unpleasant task that nobody wants to do. Spending time removing hundreds of nozzles from a filthy and hazardous pre-treatment tunnel is never high on anyone's list of preferred activities. Some of the chemicals used are highly toxic, and there is a significant health and safety risk associated with pre-treatment nozzle maintenance.

When it comes to changing out nozzles in a pre-treatment line, the process can be quite time-consuming. Each individual nozzle needs to be removed, checked, cleaned, replaced, and then readjusted.

To streamline this process, SYNERGY recommends using the Uni-Spray nozzles for quick changeovers. These nozzles have tips that fix in place, so the system does not need to be touched. The tip snaps back in at the same point, which means that re-alignment is not necessary.

Since the tips are often the component that wears out, our recommended best practice is to keep two sets of complete tips on hand at all times. When cleaning is necessary, the old tips can be snapped out and replaced with the spare set. Since no re-alignment is required, this can be done quickly, and the pre-treatment line is ready to operate with the new set of tips. The old tips can then be checked, cleaned, and swapped out in preparation for the next cleaning cycle. By maintaining a full set of tips, downtime due to cleaning and maintenance can be minimized. Fortunately, replacement tips are only a fraction of the cost of the entire nozzle.