GEMÜ glossary for valves and

automation components

GEMÜ glossary for valves and

Our glossary provides an explanation of around 400 technical terms and abbreviations relating to the pipeline construction sector. It focuses on valves, measurement and control systems and their areas of application.

Ea more
​Activation energy, reaction-kinetic variable; measure of the temperature dependency of the speed of a chemical reaction or the killing off speed. less
Echo procedure more
​See Ultrasonic measurement
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EFB more
European Federation of Biotechnology
c/o DECHEMA, Postfach 97 01 46, 6000 Frankfurt/M. 97, other offices in London and Paris.
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EHEDG more
​European Hygienic Equipment Design Group
The EHEDG is an independent consortium founded to create recommendations and test methods for safe and hygienic processing of foodstuffs. The EHEDG is a committee of experts which sees itself as a supplier of expertise to CEN. Members of this group are equipment manufacturers, research institutes and food companies. This arrangement offers a good opportunity of finding regulations which particularly reflect the user’s point of view. Members: Food producers, research institutes, equipment manufacturers. Work groups: design criteria, test method, pumps, valves, packing machines, connections, sensors, heat treatment.
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Elastomer more
​An elastomer is a rubber that can be elastically deformed to a certain degree through plastic deformation and returns to its original form when the applied stress is removed.
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Electrical control more
​Is a method of control during which electrical reference signals are used to transmit the reference variable W (set value) and the measurement variable Z (actual value) and an electronic controller is used to electrically actuate an electrical positioning element (purely electrical control).
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Electro-deionisation more
​Electro-deionisation is a procedure for ion exchange and simultaneous electrodialysis.
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Electropneumatic / electrohydraulic control more
​Is a method of control during which electrical reference signals are used to transmit the reference variable W (set value) and the measurement variable Z (actual value) and an electro-pneumatic positioner pneumatically actuates a pneumatic positioning element (the electronic system is used for complex calculation processes and compressed air is usually used for power control).
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Electropolishing more
​Electropolishing: The procedure is based on a reverse galvanic process and is used for deburring, smoothing and cleaning metal bodies and their surfaces. In principle, Electropolishing or E-polishing is the opposite of the well known galvanising or plating process.
In the process known as "galvanising" chrome, nickel or gold are applied to surfaces as protection or refinement (e.g. on screws and jewellery).
In electropolishing on the other hand material is removed specifically from the surface of a metal object. The workpiece acts here as an anode, the flow of direct current is reversed. A conductive liquid – the electrolyte – serves as an electric conductor. The material is removed by the electron flow in the process. The "lost" material collects on the cathode. Components of stainless high grade steel alloys are mainly used in sterile processes.
To guarantee their easy cleanability and reliable sterilisation, optimised surfaces are necessary. Although the surface can be improved measuring technically and optically by grinding and mechanically polishing, such surfaces are not necessarily optimum in terms of process technology. The reason for this is that a ground surface is merely "finely scratched" and its surface area increases as a result. Grinding residue is also often left behind in the soft high grade steel surface. A later electrolytic polishing removes this grinding residue and produces a homogeneous surface – free from "peaks" and "valleys". Ideally electrolytic polishing can be done so specifically that the structure of the high grade steel is completely exposed and the mean roughness value is only defined by the differences in height of the austenitic crystals of the material. However this is only possible to completely level surfaces so that the curved surfaces of pipes, fittings, valves and pump housings can never reach this perfect state. If a surface is mechanically fine polished and perfect from a measuring technical point of view, later electropolishing will result in a worse measured test result. This is due to the fact that the electrically polished surface has a "wavy" structure which although it is more favourable process-technically is poorer in measuring technical terms. For this reason the surfaces of devices for sterile applications are usually mechanically polished to a higher quality in an initial step and then finished of to the required quality by E-polishing. This guarantees that the polished surface meets requirements in all respects.
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Emulgator more
​An emulgator reduces the interfacial tensions of two unmixable liquids in order to enable mixing of the two liquids. E.g. protein in milk and water.
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Emulsion more
​An emulsion is a liquid mixture comprising two or more liquids, which would not be mixable in their normal state, but can be recognized as a whole due to their finely distributed particles. It is a dispered system of finely distributed droplets. (Example: Milk). An emulsion would separate again without the addition of an emulgator.
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EMVG more
​Is a law on the electromagnetic comptability of operating media in which it is stipulated that the electromagnetic interference caused by a device must not interfere with the operation of other devices and that the device itself must be sufficiently insensitive to electromagnetic interference.
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Enzyme more
Enzymes are predominantly proteins with the property of being able to catalyse biochemical reactions.
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Eucomed more
​European Confederation of Medical Suppliers Association, 551 Finchley Road, Hampstead, GB-London NW3 7BY.
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Explosion protection more
​In potentially explosive areas, such as in the petrochemical industry, it must be guaranteed that operating media do not cause a danger of explosion in these areas. therfore, operating media are approved for use in an exprotected area by an approval mark.
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Externally controlled more
​In terms of valve designs: ​Control/actuation of valves using an external medium – not the working medium. Usually compressed air between 4-7 bar, but also other inert gases, water or hydraulic oil.
Control function 1: Normally closed (e.g. closed by spring force),
Control function 2: Normally open (e.g. opened by spring force),
Control function 3: Double acting.
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Extinction rate more
​Percentage of micro-organisms killed under defined conditions in a sterilisation process. The extinction rate is defined in a dimensionless number.See also D-value. 
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Extraction more
​Extraction is the separation of a specific substance from another substance with the help of a solvent.
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F-value more
Evaluation of a sterilisation method. The F-value identifies the exterminatory effect of a sterilisation process and specifies for example the treatment time in minutes for the heat sterilisation method (exposure time at process temperature) which is necessary to reduce an existing amount of germs to a desired end value at the applied process temperature.
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Fahrenheit more
​Used in Anglo-American countries.
Temperature scale with two calibration points of the German Daniel Gabriel Fahrenheit (1686 – 1736). Conversion of temperatures: °C = 0,556 (°F – 32), °F = 1,8°C + 32.
e.g. -5 °C = 23 °F, -10 °C = 14 °F, -15 °C = 5 °F, -17.8 °C = 0 °F
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Fail-safe-engineering more
​Engineering to avoid accidents and dangers caused by the failure of the system.- For example: By transferring the system into a non-hazardous state.
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Failure more
​A state of unforeseeable interruption o fthe function of a machine or device. A failure can have non-hazardous or hazardous causes.
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FAO more
Organisation of the UN for the foodstuff branch
​Food and Agriculture Organisation of United Nations, Via delle Terme die Caracalla, I-00100 Rome.
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FDA more
​North American Health Administration US authority which issues the release for products and the licenses for materials for use in the food and pharmaceutics industries. Food and Drug Administration, 5600 Fisherlane, Rockvill, MD 20857, USA.
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Fermentation more
​Originally the fermentation of carbon compounds by micro-organisms to the exclusion of oxygen. Later also used for fermentation in general. Fermentation generally refers to metabolization by micro-organisms as a way of converting substances – e.g. turning sugar into alcohol. The container used for the fermentation process is referred to as a fermenter. The container used for the breeding of micro-organisms is referred to as a bioreactor. Since the breeding and use of genetically modified yeast cells to produce, for example, the vaccine against hepatitis B is a combination of breeding and metabolization, it is not always possible to make a clear distinction between bioreaction and fermentation, as both take place within the same environment. For this reason, a linguistic distinction is not made nowadays and all containers used for breeding and metabolization are referred to as fermenters.
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Fermenter more
​See Biorector
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Fibre composite more
​A fibre composite is a plastic that is reinforced with fibres of various substances. One of the most well known fibres composites is glass fibre reinforced plastic (GFRP).
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Fieldbus more
​A fieldbus is a communication system for the transmission of binary information between automation systems and the connected local field devices such as measurement probes and actuators.
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Filter cake more
​A Filtercake is the residue that collects in the filter following a filtration process. Depending on the duration of filtration, the filter cake becomes bigger and increasingly blocks fine particles from passing through (clogging).
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Filtration more
​Filtration is a mechanical procedure for separating a substance from a medium flowing through the filter.
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Final sterilization more
Final sterilization usually involves filling and sealing product containers under high-quality ambient conditions. The products are filled and sealed in this type of environment in order to minimize the microbial and particle content of the product during the process and to ensure that the subsequent sterilization process is successful. In most cases, the product, container and closure have a low bioburden, but they are not sterile. The product is then subjected to a sterilization process, e.g. heat or radiation, in its final container.
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FIP more
​International Association of National Pharmaceutical Organisations (Apothecaries)
Fédération Internationale Pharmaceutique, 11 Alexanderstraat, NL-2514 Den Haag.
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Flameproof enclosure more
​Is the containment of a unit in a housing, which, in the event of a possible explosion in the interior, guarantees no transfer to the outside.
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Flange more
A flange is a method of connecting two parts. Flanges are usually used to close off, position and connect together two component groups using their pressing force. Flanges on pipes are often sealed.
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Flocculating agent more
A flocculating agent can cause particles in a suspension to join together, so that they can be extracted through sedimentation.
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Flow coefficient more
​Symbol: Kv in metric zones and Cv in imperial zones of the USA (then measured in PSI and US gal per minute).
KV (VDI/VDE 2173 and DIN-ISO-EN) is the flow coefficient of a valve and is expressed as a key figure. It is determined under standard conditions and can therefore be used as a way of comparing valves and as the mathematical basis for calculations in the case of deviating operating conditions. A flow constant resulting from a pressure difference of ∆p 1 bar, a test temperature in the surrounding atmosphere and the fluid between 5 °C and 30 °C (usually 20 °C) and the uniform, liquid test medium with a density of 1000 kg/m3 and a kinematic viscosity of 10 -6 m2/s (water, H2O) enable the valves to be compared based on a common denominator. The measurement result is expressed as a number. This number is the key figure for the valve. If no unit of measure is assigned to the key figure, this means that the key figure refers to cubic metres per hour (m3/h). If the key figure refers to a different unit of measure, this unit of measure must be directly assigned to the key figure (e.g. 3200 l/h).
All valves can be tested at any inlet pressure chosen by the manufacturer. Only the difference of ∆p 1 bar between the inlet side (p1) and the outlet side (p2) must be observed. The diaphragm valve is an exception. With this functional principle, the pressure-dependent change in cross-section due to the diaphragm deformation means that half the permissible maximum operating pressure of the respective valve is usually set as the inlet pressure. The valve can be opened or closed to any degree, which means that a characteristic curve throughout the entire stroke/travel range, for example, can be determined depending on the valve position. Formulae are used to take into account all the parameters and physical variables deviating from the test. Since liquids, gases and steam are subject to different laws, different formulae are also used. The standardized calculation formulae are very extensive, therefore the general "simplified" formulae are used in most cases. Here it is important that they cannot be fully abbreviated and the unit used respectively for the value Q or the Kv value is identical.
 
KV: KV measured value: Value of an individual valve in any opening position.
KVS: Prescribed KV measured value for an identical series of fully open valves.
KV 10, KV 20........KV 100: KV measured value of an individual valve in the specified opening position (%).
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Flow measurement more
​Flow measurement is the technical determination of the volume of currently flowing medium in relation to the cross section of a pipe or other geometry.
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Food hygiene more
​Covers all measures during manufacture and treatment of foodstuffs which guarantee the consumability of foods by humans and animals.
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Foodstuffs more
The term foodstuff designates food items, that are primarily consumed by humans for nutritional purposes (please refer to "food") and contain macro nutrients (proteins, carbohydrates and lipids) to provide humans with energy.
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Form deviation more
​Total of all deviations of the actual surface of the geometric surface
According to DIN 4760, sub-section 2.4.See also Surface.
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Free outlet more
Term used in piping and tank construction. ​Is present if the working medium emerges unhindered from the piping and in the immediate vicinity of the valve. No backlog factors may be allowed to affect the fluid/working medium (e.g. heads of water due to differences in height, nozzles and plates, pipe runs that are too long downstream of the end valve).
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Free outlet angle more
Applies to the field of valve installation. Alternative term for discharge angle (see Discharge angle).
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Free outlet angle more
Applies to the field of valve installation. Sometimes incorrectly used to refer to the discharge angle. The name can give the false impression that a plant, plant section or container can be completely drained without leaving residue without any assistance (see Discharge angle). less
Freeze- drying more
​Freeze-drying is the procedure of sublimation, i.e. water in ice form can be evaporated without entering its liquid state and can be extracted from a substance in this way.
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Freeze-drying more
​Freeze-drying is the procedure of sublimation, i.e. water in ice form can be evaporated without entering its liquid state and can be extracted from a substance in this way.
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Functionality more
The mechanical, pneumatic, hydraulic, motorized or electromagnetic function/actuation/working method of a device.
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