High Pressure Isn't Always as Effective

High pressure isn't always as effective

Multiple decisions play a role in maximizing efficiency during the process of cleaning commercial tanks and equipment. Choosing to use spray nozzles instead of manual cleaning is important. Selecting the ideal tank cleaning device for your application is equally critical. Rotating or static? Efficiency class one or two? How many nozzles should I use, and which nozzle is best for a tank of my size?

However, once you’ve determined the very best option for your company, maximizing cleaning efficiency is not over. Specific details, such as pressure and impact, are equally important for optimal efficiency, accuracy, and consistency. Below, we explore one seemingly small, yet important aspect in tank and equipment cleaning: operating pressure.

Mechanical Cleaning with Rotating Nozzles

When cleaning the surface area of a tank, rotating cleaning nozzles deliver the greatest impact. This is accomplished when large droplets strike the sides of the tank at high speeds. Optimal impact is achieved when two dynamic factors work simultaneously: distance between the nozzle and the wall and operating pressure.

As counterintuitive as it may seem, high pressure is not always the most effective option, because higher pressure does equate to higher impact. In fact, if operating pressure or distance between nozzle and wall aretoo great, the fluid will break down into smaller droplets.

What is Impact?

The impact of a liquid jet against a surface plays a crucial role in the cleaning process. What is impact, exactly? Impact is simply the ratio of force to the surface. Impact surface and spray angle, flow rate, and pressure function to control impact.

Impact Surface and Spray Angle

Simply put, impact surface is the area of the tank where the droplet strikes. Impact value directly correlates with the size of the surface area. For example, a large surface area devalues impact. As surface area decreases, impact value increases. Nozzles classified as “high impact,” such as solid stream nozzles or flat fan nozzles, have a narrow spray angle (i.e. small surface area) and high impact value.

Flow Rate

Flow rate is determined by the gal/min utilized during cleaning. As long as spray angle, pressure, and medium remain the same, increasing the flow rate by using larger spray nozzles will increase impact.


For rotating nozzles, pressure and impact have no linear relationship. Supply pressure simply influences rotation speed. Increased pressure equates to increased rotation speed. Higher supply pressure is not always effective. In fact, extremely high rotation speeds will atomize droplets into smaller droplets, reducing impact.

Examining Recommended Pressure and Maximum Impact

Lechler nozzles are designed to operate with optimum impact at the right operating pressures. Some function under high pressure, others operate under lower pressures. Below, we discuss a few specific nozzles, along with their ideal operating pressures to demonstrate the unique relationship between pressure and impact.

Free-Spinning Nozzles

Free-spinning nozzles are powered by the cleaning fluid. The spray head rotates as the fluid sprays, producing rapid-repetition impact, excellent for washing dirt from tank surfaces. This effect is best achieved at low pressures. A small selection of free-spinning nozzles that operate with incredible impact at low pressures include:

  • Series 566 “MicroWhirly:” the MicroWhirly functions from a recommended operating pressure of 30 psi. It can be run in every possible direction and can withstand temperatures of up to 266 °F. This compact nozzle is excellent for cleaning in confined spaces.
  • Series 594 “Hygienic Whirly:” the HygienicWhirly functions from 45 psi operating pressure. Once more, this nozzle can operate in any direction, withstand high temperatures, and is excellent for hygienic requirements and for applying foam.
  • Series 5MC “MicroSpinner:” like the MicroWhirly, the MicroSpinner functions best at 30 psi. Utilized in tanks with a max diameter of 6 ft, the nozzle is reliable, durable, and built for tanks with smaller openings.

Controlled-Rotation Nozzles

Controlled-rotation nozzles are also driven by fluid flow. However, unlike free-spinning nozzles, a turbine wheel with an internal gear is used to control the pattern of rotation. Even at higher pressures, the spray impact is not compromised because larger droplets can still be achieved. Two excellent examples of controlled-rotation nozzles are listed below:

  • Series 5S2/5S3 “XactClean HP+:” The XactClean HP+ operates at a pressure of 75psi.  As odd as this fact sounds, it confirms our prior claims that higher pressures are not always as effect and high pressure does not equate to high impact.
  • Series 515 “ACCUClean:” ACCUClean operates best at 45 psi. With precise efficiency, this nozzle cleans tanks of up to 26 ft in diameter at max temperatures of 284 °F.

Gear Controlled Nozzles

Built for battling persistent soiling, gear-controlled nozzles function at the extremely high impact under extremely high pressures. High-grade gear units work with measurably controlled rotation and run on two axes. These powerful jets sweep the entire tank surface by utilizing a specific pattern. Due to their extraordinary impact, they are often utilized in the food and beverage, chemical, petrochemical, and paper industries.

  • Series 5TB “IntenseClean Hygienic:” Efficiency and effectiveness convene in the “IntenseClean Hygienic.” This nozzle operates at a recommended pressure of 75 psi and is utilized in tanks up to 49 ft diameter. Operational in every direction possible, the 5TB contains ball bearings and is sensor compatible.
  • Series 5TM: The Series 5TM is a high impact tank cleaning nozzle and relatively easy to maintain and repair. Like the Series 5TB, the 5TM operates at 75 psi; however, this nozzle operates in tanks of up to 79 ft in diameter.

Lechler: Engineering Your Spray Solution

For over a century,Lechler has been engineering evolutionary spray solutions for a wide variety of industries, serving markets from food and beverage, chemical, steel, and power generation. We are more than just a nozzle manufacturer, however. We provide custom engineered spray solutions. We offer extensive resources to expand your spray application knowledge. We are here to guide your business into the most efficient and effective organization it can be.

Get in touch with us today at (800) 777-2926 or via our online contact form to begin a conversation. We look forward to offering more information!