Atomizing Nozzles: Common Questions About Viscosity

As EXAIR Atomizing Nozzles become more popular with our customers, we are getting a lot of interesting questions that folks have regarding the nozzles themselves and the information that we provide so the customer can make an informed decision.

One set of questions has to do with the flow rate information presented in our technical data for the Atomizing Nozzles. The question is, “What is the fluid that is being used to derive your flow data given in the charts?”  That answer would be plain old water (H2O).  The next question that comes is, “What if my fluid has a higher viscosity? How do I figure out the flow rate that will apply to that?”

The answer is that you will not know until you actually perform a test with your specific material. However, if you apply some simple logic to the question, a higher viscosity fluid is going to flow less than water through an Atomizing Nozzle. So, to compensate, you can select an Atomizing Nozzle size which has a higher water flow rate in order to compensate for a thicker fluid. A chart for viscosity of common fluids can be accessed here.

You do have options in terms of which style of Atomizing Nozzle you choose for the application. For example, fluids that have viscosity up to 200 centipoise can work well with either a siphon type or an internal mix type Atomizing Nozzle (an internal mix type can work with viscosity up to 300 centipoise). The siphon nozzle option is for applications where the fluid is not pressurized but is available from a nearby container (this can also be set up to be gravity fed type depending on the height of the fluid in relation to the nozzle). The internal mix nozzle is used when the applied liquid can be pressurized by a pump or perhaps by a pressure pot.

For applications where the fluid is over 300 centipoise, an external mix Atomizing Nozzle is the suggested product to use. Because the air and the pressurized fluid mix out in front of the nozzle, the liquid is not subject to the back pressure present upon it in an internal mix nozzle configuration. Therefore, the liquid pressure and air pressure are completely independent. This means a much higher pressure can be used on the high viscosity fluid to push it through the nozzle and be atomized.

The variety of nozzles available with different configurations, flow rates, spray patterns and abilities can be a little difficult to navigate without some help. That is expressly why we are here.  To help customers determine what they need in this range of product.

If you have been considering an Atomizing Nozzle for an application, please let us know if you have any questions or just want to talk things over to make sure you are headed in the right direction. We are here to help make the decision an easy one.

Neal Raker, Application Engineer
nealraker@exair.com