In numerous industries such as chemical, food, and pharmaceutical manufacturing, tank cleaning is a critical step in ensuring production safety and product quality. The spray nozzle, as the "heart" of the cleaning system, directly determines cleaning efficiency, energy consumption, and safety. Choosing the wrong nozzle can lead to a series of serious problems, such as incomplete cleaning resulting in residual substances affecting subsequent production, equipment corrosion shortening the lifespan of the tanks, and even potential safety accidents, causing significant economic losses and safety risks for businesses. Therefore, a thorough understanding of nozzle design, selection criteria, and future development trends is crucial for companies in these industries.
Nozzle Structure Design
Rotating Jet Nozzle
Rotating jet nozzles offer unique advantages, providing 360° coverage, making them ideal for cleaning large-volume tanks such as oil tanks and chemical storage tanks. In large tanks, ordinary nozzles may not be able to cover all corners, while rotating jet nozzles, through their rotation, can evenly spray the cleaning medium to every part of the tank, ensuring thorough cleaning without blind spots.
When selecting a rotating jet nozzle, several key points need attention. First is the rotation speed, which should be ≥200 rpm. If the rotation speed is too low, the nozzle may have blind spots during rotation, resulting in some areas not being effectively cleaned. Second is the sealing level; an IP68 sealing level should be chosen to effectively prevent leakage. In environments such as chemical storage tanks, leakage of the cleaning medium can lead to resource waste, environmental pollution, and even safety accidents.
Fixed Multi-Hole Nozzle
Fixed multi-hole nozzles have a simple structure and low cost, making them widely used in cost-sensitive applications, especially for regularly shaped tanks, such as square tanks. Their working principle involves simultaneously spraying the cleaning medium through multiple small holes to clean the tank.
However, fixed multi-hole nozzles also have some drawbacks. When the hole diameter is <2mm, the nozzle is prone to clogging. This is because the cleaning medium may contain small impurities that can easily clog the small holes, affecting the normal operation of the nozzle. Therefore, when using fixed multi-hole nozzles with small hole diameters, a 100-mesh filter should be used to filter the cleaning medium and reduce the possibility of impurities entering the nozzle. Additionally, in multi-nozzle systems, pressure equalization design is necessary to ensure that the pressure difference between each nozzle is ≤5%. Excessive pressure differences can lead to insufficient spray pressure in some nozzles, affecting the cleaning effect.
Intelligent Cleaning Robot
Intelligent cleaning robots are suitable for special scenarios, such as high-risk environments (flammable and explosive tanks) and complex structures (around agitator blades). In high-risk environments, manual cleaning poses significant safety risks, while intelligent cleaning robots can replace human operators to clean inside tanks, ensuring the safety of personnel. In complex structures, ordinary nozzles may not be able to reach some hidden areas for cleaning, but intelligent cleaning robots can effectively clean these areas through their flexible movement and intelligent control.
Intelligent cleaning robots have several technological highlights. They utilize magnetic adsorption or tracked movement methods, adapting to the cleaning of curved tank walls. The magnetic adsorption method allows the robot to firmly adhere to the tank wall, preventing it from falling off due to the impact of the cleaning medium; the tracked movement method allows for flexible movement on the tank wall, reaching all areas that need cleaning. In addition, the intelligent cleaning robot integrates a visual positioning system, which can adjust the cleaning path in real time. Through visual sensors, the robot can identify the internal structure of the tank and the distribution of stains, planning the optimal cleaning path according to the actual situation, thereby improving cleaning efficiency and quality.
Selection Pitfalls Guide
Material Misconceptions
In the nozzle selection process, the choice of material is crucial. Some companies blindly believe in expensive alloys, thinking that Hastelloy is a panacea, but this is not actually the case. For example, when cleaning water tanks, PVDF nozzles are more cost-effective. Although Hastelloy has excellent corrosion resistance, it is expensive. In the case of cleaning water, which has relatively low material requirements, using Hastelloy would result in wasted costs.
In addition, the selection of seals is also easily overlooked. Fluorocarbon rubber (FKM) O-rings are prone to swelling in high-temperature oil tanks, leading to seal failure. This is because high-temperature oil chemically reacts with fluorocarbon rubber, changing its properties. In this case, perfluoroelastomer (FFKM) should be used instead. Perfluoroelastomer has better high-temperature and chemical corrosion resistance, making it suitable for high-temperature oil tank environments.
Structural Misconceptions
Some companies blindly pursue complete coverage when selecting nozzles, excessively increasing the number of nozzles. However, this can lead to insufficient system pressure, because each nozzle requires a certain pressure to function properly. Too many nozzles will disperse the pressure, resulting in suboptimal spray performance for each nozzle. A reasonable solution is to adopt a combination of "high-pressure spot spraying + wide-area coverage." High-pressure spot spraying is used for deep cleaning of key stained areas, while wide-area coverage nozzles are used for preliminary cleaning of the entire tank, improving cleaning efficiency and quality.
Furthermore, fluid characteristics need to be considered. For high-viscosity media, such as crude oil, the nozzle flow rate will drop sharply if no preheating treatment is performed. This is because high-viscosity media have poor fluidity at low temperatures and cannot easily pass through the small holes of the nozzle. Preheating the high-viscosity medium to 40-60℃ can reduce its viscosity, improve fluidity, and ensure that the nozzle can spray normally.
Maintenance Misconceptions
In terms of nozzle maintenance, some companies have the problem of only replacing instead of repairing. In fact, 90% of clogged nozzles can be regenerated through ultrasonic cleaning, at a cost of only 20% of a new nozzle. Ultrasonic cleaning utilizes the cavitation, acceleration, and direct flow effects of ultrasound in liquid to directly and indirectly act on the liquid and dirt, causing the dirt layer to be dispersed, emulsified, and peeled off to achieve the cleaning purpose. Through ultrasonic cleaning, impurities inside the nozzle can be removed, restoring the normal function of the nozzle and extending its service life.
In addition, the lack of data monitoring is also a common problem. If pressure/flow sensors are not installed, it is impossible to warn of the gradual failure of the nozzles. As the usage time increases, the nozzles may experience wear and clogging, leading to changes in pressure and flow. By installing sensors, the pressure and flow of the nozzles can be monitored in real time, and warnings can be issued in time when abnormalities occur, allowing for timely maintenance and replacement, avoiding affecting the cleaning effect and production schedule.
Future Trends
IoT Integration
In the future, nozzles will feature IoT integration. Nozzles will have built-in sensors that transmit wear data in real time. Through IoT technology, this data can be transmitted to a monitoring center, allowing staff to analyze and interpret the data, predict nozzle wear in advance, and implement predictive maintenance. This will prevent sudden nozzle failures during cleaning, reduce downtime, and improve production efficiency.
Water-Saving Design
Water-saving design is also a key trend in future nozzle development. Using a circulating water system combined with intelligent variable frequency control can save more than 50% of water compared to traditional methods. The circulating water system recycles, filters, and reuses used cleaning water, reducing water waste. Intelligent variable frequency control automatically adjusts the pump speed and flow rate based on actual cleaning needs, avoiding unnecessary energy consumption and water waste.
Green Materials
In terms of materials, bio-based plastic nozzles (such as PA11) will gradually replace petroleum-based materials. Bio-based plastic nozzles offer excellent performance while reducing the carbon footprint by 30%. Using bio-based plastic nozzles reduces reliance on petroleum resources, lowers carbon emissions, and aligns with the requirements of sustainable development.
When selecting and using tank cleaning nozzles, several factors need to be considered, including structural design, material selection, and maintenance. Furthermore, with continuous technological advancements, nozzles will evolve towards intelligence and sustainability. Companies should closely monitor these development trends, choose nozzles that suit their production needs, improve cleaning efficiency and quality, reduce production costs, and achieve sustainable development.
