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ystral is an expert company in the field of process engineering. Some of our terms are very industry-specific or even very company-specific. Would you like to understand our products and processes better or find out more about specific terms? Our glossary contains explanations about the most important terms of the industry and our company.

  1. 3A Sanitary Standards
  2. 3A Sanitary Standards
  3. Guidelines for food processing systems

    Consumers should be able to expect that strict hygienic standards regulate how their food is processed. Contaminated foods may be harmful.

    3-A Sanitary Standards (3-A SSI) establish standards and guidelines for systems used to process foods. These standards are prepared in collaboration with health authorities and industry experts. The 3-A Sanitary Standards organisation was founded in the USA to create standards for dairy equipment and systems, and for production, processing, and packaging dairy products.

    The hygiene guidelines require foods to be protected against contamination with germs or other contaminants. To do so, all contact surfaces must be able to be cleaned and/or sterilised. In addition, some components must be able to be removed easily for manual cleaning.

    3-A SSI assesses the hygienic design of a system or of a company as a whole. If a company or a device passes the test, it will receive a certificate with a test mark. The guidelines used in the 3-A Sanitary Standards are recognised in many countries and by many food manufacturers.


  4. Agglomerate
  5. Agglomerate
  6. The term agglomerate comes from the Latin word "agglomerare" and means "to connect firmly". An agglomerate is the accumulation of previously loose components to form a solid compound. In certain applications, agglomerates are intentional, for example in the case of tablets. They are produced by so-called press agglomeration, i.e. the powder (or granulate) is pressed into a defined shape by applying pressure. Build-up agglomeration is also a technical process in which granulate is specifically produced. An agglomerate is held together by weak forces such as Van der Waals forces or simple physical entanglements.

    However, agglomerates are undesirable in many applications. They can lead to undesired results in mixing processes. Therefore it must be ensured that they are dissolved. If agglomerates are dispersed, they are crushed into primary grains.

    By the way, you can already witness agglomerates in your own household. If the cocoa powder ends up in the milk, lumps are formed which do not dissolve even after long stirring.

  1. ATEX
  2. ATEX
  3. ATEX (derived from the French term Atmosphères Explosibles) represents two European directives, and regulates explosion protection within Europe. All EU members are obligated to implement these directives in their own national law.

    The Equipment Directive (2014/34/EU, formerly 94/9/EC) regulates marketing issues and puts requirements in place for equipment, components and protective systems used in explosion hazard areas. The directive is implemented in German law through the Explosion Suppression Product Ordinance (11th ProdSV).

    The Workplace Directive (1999/92/EC) – implemented in Germany through the Industrial Safety Directive (BetrSichV)) – defines measures for protecting employees who work in explosion hazard areas. The employer is obligated to complete and document a risk assessment. The goal is to avoid explosive atmospheres. If this is not possible, all active ignition sources that could cause an explosion must be eliminated. If both basic requirements cannot be effectively prevented, then the effects of an explosion must be reduced to a harmless level.

    All ystral machines and systems can be supplied in an ATEX conform design, if necessary.

  1. Bernoulli Principle
  2. Bernoulli Principle
  3. Bernoulli's principle - or Bernoulli's equation - states that in a stationary flow of incompressible fluids the total energy of the flow elements along a streamline is maintained.

    1. CIP - Cleaning in place
    2. CIP - Cleaning in place
    3. Systems used to process foods, drinks, or pharmaceutical products must fulfil high hygienic standards, and therefore must be cleaned regularly and thoroughly. However, disassembling the production systems to clean the surfaces that come into contact with final products would be too complex and time-consuming. Therefore, such technical process systems are cleaned at their locations. This is called Cleaning in Place (CIP). To ensure that cleaning achieves the same results every time, CIP is a stipulated and reproducible process. Cleaning agents, pressure, temperature and application time are all clearly defined for each system. The individual steps used in the cleaning process may vary by product, however, cleaning always includes rinsing steps during which product and cleaning agent residue are flushed out of the system using clean media.

      The cleaning process is controlled automatically in most cases. CIP is commonly carried out after a production run or before converting production to other products.

      CIP has multiple advantages: It effectively avoids cross-contamination and product contamination. CIP reduces cleaning time and costs, and energy costs for CIP are relatively low. All industries benefit from having a cleaning process that is easy to control, so CIP ensures high hygiene standards can be maintained. Overall, CIP is a process that is easy to integrate with all operational procedures.

      ystral machines and systems can be designed to work with CIP processes. Riboflavin tests, also called fluorescence tests, can be carried out to verify cleaning effectivity .

      1. Factory Acceptance Test (FAT)
      2. Factory Acceptance Test (FAT)
      3. In the "Factory Acceptance Test" a customer tests the functionality of a machine, system or software at the manufacturer's site.

        The customer and the contractor check a machine or plant for the completeness of its components. For this acceptance test, the specifications of the user requirement specification are checked, as well as any later agreed and contractually stipulated changes.

        In addition, a (reduced) functional test can be carried out. The functional capability of the machine or plant was previously documented by the manufacturer in test reports. It must be possible to reproduce these results at the customer's production site in the presence of the customer. This is because if a machine or plant does not work properly at the customer's site later on, the origin of the damage can be narrowed down: It must then be a transport or final assembly damage.

        If there were no or only insignificant defects, the machine or plant is accepted. If, however, significant defects are found during the Factory Acceptance Test, the manufacturer must repair the fault. The customer can also accept the defective machine or system, in return for which he receives compensation, for example a price reduction or a cost-reduced supply of spare parts.

        The Factory Acceptance Test is documented in the acceptance protocol, which is signed by the customer and the contractor.

        The Factory Acceptance Test is usually followed by the Site Acceptance Test (SAT) at the customer site.

      1. Fluid mechanics
      2. Fluid mechanics
      3. Fluid mechanics  is the science of the physical behavior of fluids, i.e. gases and liquids. The knowledge gained in fluid mechanics serves, among other things, to solve engineering flow problems, for example in mechanical and plant engineering or in mechanical process engineering.

        Depending on the condition of the fluid and the boundary conditions, fluid mechanics comprises various sub-areas that provide approaches to solutions for the optimal design of technical systems

      1. Homogeneous
      2. Homogeneous
      3. The word "homogeneous" means "of the same or a similar kind or nature". It has a wide range of application, it is used in natural sciences as well as in social sciences. In natural sciences, for example, one speaks of a homogeneous mixture when the components contained in the mixture are evenly distributed. In  natural sciences, the equality of a property over the entire extent of a system or the similarity of elements, objects and phenomena of a system is essential. The opposite of "homogeneous" is "heterogeneous". Here, too, the approach can be decisive: milk is heterogeneous at the microscopic level, where one can distinguish between fat and water, whereas at the macroscopic level milk is homogeneous. However, if the milk is left standing for a longer period of time, it can again become a heterogeneous mixture, because then fat (cream) and water separate. If you want to prevent this, you have to "homogenize" the milk. The process by which a substance or system is made homogeneous is therefore homogenisation.

        1. Principle of Mass Continuity
        2. Principle of Mass Continuity
        3. According to the principle of continuity the mass flow of an incompressible fluid in a pipe or line is the same at all points - no matter where it is measured. As a result, the flow velocities of a pipe system are inversely proportional to the pipe cross-sections.

        1. Process Engineering
        2. Process Engineering
        3. If you want to change a substance (liquid, solid, gas), you have to use a certain procedure. Chemical, physical and biological processes are used to change substances. In order for these processes to be technically implemented, apparatus and machines must be developed and built.

          Process engineering includes chemical process engineering, mechanical process engineering, thermal process engineering, electrochemical process engineering and bioprocess engineering. The fields of application are the food, chemical, pharmaceutical and paper industries as well as waste management, metal, textile and building material industries.

          ystral offers proven processes for industry- and product-specific tasks in the fields of dispersing, mixing, homogenizing, wet milling, emulsifying, powder handling, etc.

        1. Rheology
        2. Rheology
        3. Rheology is the study of the deformation and flow behaviour of matter. Of importance are viscosity, structural viscosity, dilatancy, thixotropy and rheopecty. A subarea of rheology is rheometry, in which rheological properties are determined by means of a measuring method. Among other things, the viscosity can be determined or how a fluid flows under shear.

        1. Rotor-stator system
        2. Rotor-stator system
        3. Rotor-stator machines can be used for different mixing, dispersing, homogenizing or emulsifying tasks. A fast-rotating agitator is surrounded by a stator, whereby the shape and size can vary depending on the application.

          Within mixing vessels, rotor-stator machines are used in particular for the controlled circulation of a vessel's contents. The shear energy can be influenced by means of slots in the rotor and stator as well as by small gap distances.

          The rotor-stator system can also be applied to inline machines. Here the machines are located outside the mixing vessel and the liquid to be dispersed is pumped through the inline machine.

          Particular advantages of rotor-stator machines are, in addition to the high product quality, shorter process times, lower air input and smaller particle sizes compared to conventional methods.

        1. Site Acceptance Test (SAT)
        2. Site Acceptance Test (SAT)
        3. The Site Acceptance Test involves the acceptance of a machine or system at its set-up location at the customer’s site. Often, this test is preceded by a Factory Acceptance Test at the manufacturer/supplier’s site.

          The first step in the SAT is a review of components and documentation to ensure they are complete. The documentation includes documents such as the handbook, operating manual, certificates, etc. In addition, a safety test must also be carried out. The emergency off function is tested, and safety doors must be able to open. If possible, a test run of the system is carried out without the product.

          Then a test run is carried out with product. This should be completed with up- and downstream product units, if possible. The test uses defined criteria to assess whether the machine or system is capable of producing or processing materials in the agreed quality.

          The SAT is recorded. If there are serious defects, these must be corrected. A time frame is set for completing the corrections. Then another SAT is carried out. The Site Acceptance Test can only be finalised once there are no further serious defects.

          1. Viscosity
          2. Viscosity
          3. Viscosity describes the resistance of a fluid or a gas to shear, under expansion or at uniform pressure. Solids also have a viscosity, but this is difficult to determine. Honey has a high viscosity, water a low one.

            A distinction is made between Newtonian fluids with a linear flow behaviour and non-Newtonian fluids. Non-Newtonian fluids have a time or shear rate dependent flow behaviour, i.e. the viscosity changes under the influence of shear.

            Knowledge of viscosity and flow behaviour helps to choose the right machine and its settings.

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