In mechanical design, for example, the wear mechanics occur between a moving shaft and its bearing.
In flow technology, the wear mechanics take the form of a damaging interaction between a flowing medium (fluid) and a surface that comes into contact with the flowing medium (e.g. steam flows through a valve or a pump conveys sandy water). The intensity of the abrasion depends on the cybernetic energy and the particle/drip potential of a fluid as well as the properties of the medium and the surface it comes into contact with. The fundamental meaning of abrasion is very close to "shaving off".
Abrasive behaviour occurs, for example, when the components of a flowing medium cannot follow the change in direction of the carrier medium quickly enough, which means that they bounce against an obstruction and transfer their dynamic energy into the obstruction (e.g. drops of liquid or solid matter within steams or gases or solid matter within liquids). If the obstruction cannot deflect or compensate for this energy, it is destroyed.
There are two measures that can be implemented in order to minimize abrasive behaviour:
Limit the flow velocity of the medium as far as possible (e.g. by restricting the pump power or by using larger cross-sections).
Design the surfaces to be either very hard or very soft (e.g. coating with glass or rubber linings).
In the case of a hard coating, the particles bounce off the surface; in the case of a soft surface the particles spring back. It is not possible to provide 100% protection against the abrasive behaviour of fluids, which means that the plant and its components must be checked regularly so that any faulty devices can be replaced in good time. Abrasion is often confused with the phenomenon of cavitation. This, however, is the pressure-/flow-dependent formation of small vapour bubbles in liquids, which, when they collapse by way of a rapid implosion, can cause material to be torn away from the surface of the stream body (e.g. in the case of propellers or in pipe bends).
Is the prevailing temperature of the ambient atmosphere on a device (e.g. a pump or a valve). Since the ambient temperature may fluctuate the possible occasional temperature peaks must also be considered in addition to the largely prevailing ambient temperature when assessing whether a device can be used. The operating and ambient temperatures are in direct relation with the temperature resistance of a device. If the manufacturer’s specifications are insufficient for an assessment or incomplete, proceed according to the temperature formula for devices. The formula can only be used if the actual ambient temperature is above 20 °C. It must be noted, however, that the manufacturer‘ specifications have priority. It the ambient temperature is below 20 °C, the formula does not work.
Operating temp.max.safe function = (operating temp.max. manufacturer spec. + 20 °C) - ambient temp.actual
In this context, national regulations concentrated in the past especially on the standardisation of electrically powered devices which was generally known under the term "EX-protection". However, other factors may also represent a source of danger. Certain materials are susceptible to dangerous static charges for example and hot surfaces may also act as ignition sources. Therefore, since 2003, the European Community has been passing laws to govern the overall assessment to protect its citizens/workers. The Directive 94/9/EC ATEX 95a (formerly 100a) exactly standardises the primary and secondary explosion protection. Primary means the avoidance, prevention or restriction of explosive atmospheres (the responsibility of the plant owner). Secondary means prevention of an explosion by using suitable technical means in the presence of ignition sources or ignitable materials (the responsibility of the equipment manufacturer). For this the danger areas (primary) are divided into zones and classified in explosion technical groups so that the prevailing danger situation can be clearly assessed and defined. To ensure the explosion protection of the planned/used devices, machines and parts (secondary) two main groups are distinguished which are defined on the one hand in the standard for electrical appliances DIN EN 50014 (and following) and on the other hand in the standard for non-electrical appliances DIN EN 13463-1. If a device, machine or single part is to be used in an explosive environment, the owner must first assess and classify the special situation. The entire equipment for this area is then procured based on this. The equipment/component providers are obliged to submit the appropriate conformity/applicability declarations if they are entitled to do so according to pertinent regulations and if the product meets requirements. The observance and implementation of other regulations and standards may be necessary for this. This always differs depending on the device (e.g. pressure equipment directive, regulations for electrical and electronic equipment, machine directive etc.).
In the context of plant engineering, this is a sterilization process in a closed container (autoclave) in which products, plant components or devices to be sterilized are placed and completely sterilized inside and out with saturated steam. Autoclaving is always preceded by multi-stage cleaning of the devices/parts to be autoclaved. There are two basic types of autoclaving: The vacuum procedure, in which the air is pumped out of the autoclave several times, alternating with an inflow of steam, and the flow or gravitation procedure, in which the air is completely displaced by saturated steam.
lessProcaryontic single-cell organisms are organisms which are distinguishable by their form, growth conditions and metabolism. The bacteria are divided into many different types and families. They can transfer diseases to humans (e.g. the bacterium borrelia burgdorferi which is transmitted by tick bites and which causes Lyme borreliosis) or may be important for a healthy bowel flora and therefore indispensable for humans (the bowel bacterium E.coli). The first molecular biology experiments and later genetic engineering experiments were made on the E.coli bacterium. The remnants of dead bacteria are often as dangerous as the bacterium itself in pharmaceutical application.
Sealing takes place via sealing rings inserted into the housing, which seal against the surface of the ball. In the most common variant, the seal is fitted on both sides - the flow direction is then arbitrary. In high-pressure/high-temperature versions, the seal is only fitted on the outlet side.
The direction of flow must then be observed. Ball valves are swivelling valves and are therefore only suitable for low switching cycles - especially in view of the seal friction. The control characteristics (characteristic curve) can be improved in special designs by optimising the passage geometry - however, the mechanical problem remains the same. As the medium gets between the ball and the housing during the opening/closing process, the ball valve should only be used with clean media. Crystallising media in particular have a negative effect on the function. In addition to the straight-through version, plug valves can also be designed in a multi-port version. Ball valves can be regarded as the technical descendants of plug valves.
Special features and advantages: Ball valves are simple in design and have a high volume flow rate. They are compact and are also available as standard in a multi-port design.
Typical areas of application: General industrial applications, steam systems, heat exchanger systems, special vehicle construction, chemicals, industrial gas production and distribution, mining and petrochemicals, building services engineering.
The micro-organism contamination of materials used in watery pharmaceutical and biotechnical production systems is well documented. There would be no organically arranged tissue without biological adhesion. Biofilm contamination thrives everywhere and keeping it under control or even exterminating it in a sterile environment is at best difficult and at worst impossible. Stubborn biofilm contamination can resist cleaning/disinfection efforts with chemicals (cleaning in place – CIP), antibiotics, eddy current abrasion and heat (sterilisation-in-place – SIP). The presence of the biofilm contamination in pharmaceutical and biotechnical production systems threatens production flows, aseptic transfer and potentially might even affect the health of customers who use the products which come from the affected plant.
Biotechnology refers to the study of all methods with which life forms from single-cell organisms to highly developed animals are used for technical purposes.
Some biotechnical methods are very, very old. Yoghurt and cheese were manufactured 3,200 years before Christ in the region now known as Iraq (Mesopotamia).
Beer or yoghurt are just as much biotechnological products as genetically engineered Interferon.
Special features and advantages: Butterfly valves have relatively short installation lengths and low weights. They are low cost in comparison with other functional principles.
Examples for areas of applications: General water treatment (filtered water), sea water treatment, reversible flow filter (rinsing medium), brewing, heat exchanger systems, special vehicle construction, air conditioning and building, chemicals, polystyrene foaming and packaging, gas cleaning, petrochemicals.