Food and Beverage Industry

Increasing Demands Require Innovative Designs

The food and beverage industry is facing enormous challenges as consumers demand more choices. Along with these demands, planning, production processes and reliability must work perfectly together to reduce costs and ensure quality. Production equipment must also meet the requirements of the new laws and regulations for this industry. Lechler offers nozzles that meet hygienic standards and our innovative designs help automate processes. Learn more.

Spray nozzles for applications in the food and beverage industry

What You Should Keep in Mind When Planning

  1. The Fundamentals of Cleaning Technology
  2. Mechanical Cleaning with Lechler Rotating Cleaning Nozzles
  3. Chemical Cleaning
  4. Impact
  5. Spray Angle and Spraying Behavior
  6. Hygienic Design and Surface Quality
  7. Fluid Distribution
  8. Droplet Sizes
  9. Temperature Behavior
  10. Viscosity
  11. Narrowest Cross Section
  12. Connections
  13. Materials and Wear 
the sinner's circle

1. The Fundamentals of Cleaning Technology

Sinner’s Circle

The Sinner’s circle illustrates the interplay between the four main factors for successful cleaning:

  • Chemistry (choice of cleaning agent)
  • Mechanical (removal of dirt with pressure or friction)
  • Temperature (at which cleaning is performed)
  • Time (duration of the total cleaning processes)

The proportion of the individual factors as a part of the entire cleaning process can be varied, provided that the total is 100 percent. This results in significant savings potentials. As a result, the intensification of mechanical cleaning enables the consumption of cleaning agents or the duration of cleaning to be reduced. Consequently, the mechanical factor takes up a greater part of the Sinner’s circle, while the other factors can end up being reduced.

Cost Reduction via Efficient Cleaning Processes

This is precisely where our nozzles and rotating cleaning nozzles come into play, having been specifically developed for delivering a high mechanical cleaning action. Their greater efficiency helps to permanently reduce ongoing costs for energy and cleaning agents, and also the duration of cleaning. Consequently, a one-off investment in improved nozzle technology pays for itself after only a short time.

2. Mechanical Cleaning with Lechler Rotating Cleaning Nozzles

Cleaning Effects

Lechler rotating cleaning nozzles deliver the greatest possible impact in order to clean the container wall. To achieve this, large droplets must strike at high speed. This enables dirt to be removed that cannot dissolve in the cleaning fluid. Important influencing variables are the distance between the nozzle and wall, and the operating pressure. Neither must be too great or the fluid will break down into smaller droplets and the impact will be reduced.

Besides the impact, the fluid running down the container wall also has a significant cleaning effect. If the formed film is thick enough, the resulting shear stresses can remove light to moderate dirt. In that case, unsprayed patches are less of an issue than is the case during impact cleaning.

Rotating Cleaning Nozzles or Spray Ball?

Due to their simple construction, spray balls are economical and have a very fine surface finish inside and outside. Whereas, rotating cleaning nozzles spray the entire container wall in a fan-like pattern, the droplets from the spray balls strike only in concentrated spots. The remaining surface is simply cleaned by the shear stresses of the fluid running off. The fluid consumption is significantly greater in comparison to rotating cleaning nozzles.

chemical cleaning process

3. Chemical Cleaning

In the majority of all cleaning processes, the chemical cleaning effect involves fluids. Either the dirt is dissolved in the cleaning fluid or the adhesion between the dirt and the container wall is reduced. Higher temperatures can support the chemical cleaning effect.

Foam Cleaning with Nozzles

Foam cleaning is primarily based on the chemical cleaning effect. Since the foam sticks more firmly to the surface, it can be effective longer than cleaning fluids that drip off quickly. The mechanical cleaning effect plays a correspondingly subordinate role. Here, the task of the nozzle is to distribute the foam homogeneously. Your choice, therefore, greatly depends on the type of foam.

 

4. Impact

The impact force of a liquid jet on a surface plays an important role in cleaning technology. The ratio of the impact force (F) to the impact surface (A) is referred to as the Impact (I). It can be controlled via the following parameters:

Impact Surface and Spray Shape

The impact surface is the area where the droplet hits. The smaller the impact surface, the greater the impact values. Nozzles with high impact are, for example, solid stream nozzles and flat fan nozzles with a narrow spray angle.

Pressure

The impact increases linearly with the connected pressure. If the pressure is doubled while maintaining the same flow rate, the impact is also doubled.

Flow Rate

Increasing the flow rate by using a larger nozzle increases the impact, assuming that the other parameters (spray angle, pressure and medium) remain the same.

 

5. Spray Angle, Spraying Distance, Spray Behavior

Depending on the application, we supply single-fluid nozzles with spray angles from 0° (solid stream nozzles) to 360° (tank-cleaning nozzles). Gravity and air flows influence the spray pattern.

Depending on the version, Lechler single-fluid nozzles can spray the fluid as a hollow cone, solid stream or flat fan. The solid stream nozzle does not spray, but rather produces a closed spray pattern that hits at a concentrated point. The droplets only begin to break up after some distance. Twin-fluid nozzles have a narrow spray angle of approximately 20° due to the high speed at which the compressible medium exits. However, as the distance from the nozzle increases, the spray pattern becomes increasingly less sharply delineated. Twinfluid nozzles normally produce full cone or flat fan spray patterns.

 

6. Hygienic Design and Surface Quality

Equipment and components must be designed accordingly so they are easy to clean. Hygienic design prevents recesses and gaps that can harbor dirt, unfavorable flow areas (dead spaces) and sinks that hinder the run-off of fluids. At the same time, attention is paid to maintaining the least surface roughness possible, max. Ra 0.8 µm. Lechler supplies various nozzles and rotating cleaning nozzles that have been designed with these requirements in mind.

For many Lechler rotating cleaning nozzles we only use materials that comply with the regulations of the FDA (Food and Drug Administration). The series 573/583 rotating cleaning nozzles and the series 527/591 spray balls also meet the strict hygiene requirements in accordance with 3-A.

liquid distribution

7. Liquid Distribution

An even liquid distribution is crucial to processes such as coating. This requires several nozzles to be arranged next to each other. This is because a single nozzle produces a parabolic liquid distribution while several nozzles arranged next to each other allow an almost even distribution via overlapping.

Measuring the Distribution

The liquid distribution in a plane can be determined with the aid of a combination of Plexiglas cylinders. The filling level of the individual cylinders is determined automatically. This measuring process can also record the liquid distribution of a nozzle over a moving measuring plane. This enables conveyor belt spraying to be simulated, for example.

8. Droplet Size

Lechler twin-fluid nozzles can produce very fine to extremely fine droplets. The size depends mainly on the flow rate ratio of the compressible medium used (m3/h) to the atomized fluid (l/min): The greater the ratio, the finer the atomization. In the case of single-fluid nozzles however, the decisive factors are pressure, nozzle type and flow rate across the droplet spectrum. Increasing pressure results in finer atomization, but mostly only up to a certain level.

Lechler hollow cone nozzles produce very fine to fine droplets at the same pressure and flow rate. Full cone nozzles produce slightly coarser droplet spectrums, and finally flat fan nozzles have the coarsest droplet spectrum.

The following generally applies: Within a series and at a given pressure, nozzles with a lower flow rate produce finer droplet spectrums than nozzles with a higher flow rate.

9. Temperature Behavior of Nozzle Materials

Applications with temperatures up to 284°F are very common. These include, for example, most cleaning applications and sterilization processes. Applications with higher temperatures are rare, and applications at very low temperatures are even rarer. The general temperature information from material data sheets must always be scrutinized for every single case of nozzle use. Pressure, mechanical stress type, chemistry and time are decisive factors for the suitability of a nozzle material at increased temperatures. Chemical processes can be more aggressive at high temperatures.

A material may be able to withstand them if this temperature occurs for a very short period only. In all materials, high temperatures result in reduced strength values. The mechanical stress type must also be taken into account in high-pressure applications in particular. In addition, vibrations in the system can cause premature failure.

10. Viscosity

Increasing viscosity of the fluid can reduce the flow rate, change the spray pattern (narrower spraying angle) and allow the droplet spectrum to become coarser.

Depending on the fluid properties, it is possible to counteract this to a certain extent by means of higher pressure. For very viscous substances, it is recommended to use twin-fluid nozzles in most cases. It can also be helpful to take account of the fluid’s rheology.

 

11. Narrowest Cross Section

The risk of a nozzle blocking depends greatly on its narrowest cross section (ØE). Experience has shown that for smooth operation, the maximum particle size in the fluid should not exceed onethird of the narrowest cross section. Hollow cone and full cone nozzles with axial flow have an internal swirl. Hollow cone and full cone nozzles with inflow at the side (tangential or eccentric design) do not need a swirl and are, therefore, much less prone to blockages. In the field of flat fan nozzles, our deflector nozzles represent a special design that is less susceptible to blockages.

 

12. Connections

Nozzles are mainly constructed with the thread standards ISO 228, DIN 2999 (EN 10226-1) and NPT. A distinction is made here between sealing and nonsealing threads. In the case of non-sealing threads, Teflon strip or a thread paste is used to provide the seal. Not all nozzles can be connected with a thread. For non-threaded nozzles, we supply flange solutions that conform to the standards DIN 2527, EN 1092-1 and ASME B 16.5. Aseptic clamp connections (Tri-Clamp connections) conforming to the standard DIN 11864-3 are also possible. Whether a connection other than the standard connection is feasible for a nozzle must be decided on an individual case basis.

13. Materials and Wear

Nozzle wear depends greatly on the conditions of use and on the nozzle material. Normally, the nozzle’s fluid discharge opening wears as a result of material abrasion. The following conditions of use can speed up wear:

  • Solids in the fluid and also hard particles
  • Operating the nozzle above the recommended pressure range
  • Using chemically aggressive substances 

The nozzle body can also wear from the outside if the nozzle is used in a harmful environment (corrosive gases, radiation, temperature, rebound water with particles).

Nozzle Wear

As wear increases, the spray pattern quality becomes increasingly worse. In most cases, this can be seen very easily with the naked eye. At the same time, a change occurs in the spraying parameters, for example an increased flow rate. The cause of the change is damage to the nozzle opening cross section due to material removal. Wear leads to a worse production result and higher costs. The included image shows an example of a heavily worn spray ball. For these reasons, regular maintenance intervals and nozzle replacement are particularly important for achieving a high degree of process capability.

Material Selection

Particularly noticeable manifestations of wear occur when fluids with a high solid content are atomized. Such particleladen fluids cause significant wear if the particles have a greater hardness than the nozzle material. This can be remedied by selecting a different material. The table below of the various materials and their average Vickers hardness is a means of approximate guidance.

 

Applications in Food and Beverage Industry

Disinfection and hygiene

Disinfection and hygiene

Product treatment

Product treatment

Filling and packing

Filling and packing

Product Prepraration

Product preparation

Contact

Lechler, Inc. Phone (800) 777-2926 Fax (630) 377-6657 info(at)lechlerusa.com