NAMUR
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No-load angle
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Non-absorbent materials
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Non-toxic materials
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OD (Outside diameter)
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Operating pressure
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Symbol: p operation
Is the pressure in a pipe system or container that is required in order to operate the plant. The pressure can, however, fluctuate within the system.
For components and devices inside a plant, the so-called "maximum permissible operating pressure" (p operation max) is critical – it must not be exceeded. The maximum permissible operating pressure must never be higher than the nominal pressure PN – its level is defined by the respective manufacturer.
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Is the pressure in a pipe system or container that is required in order to operate the plant. The pressure can, however, fluctuate within the system.
For components and devices inside a plant, the so-called "maximum permissible operating pressure" (p operation max) is critical – it must not be exceeded. The maximum permissible operating pressure must never be higher than the nominal pressure PN – its level is defined by the respective manufacturer.
Operating temperature
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Symbol: t operation
Is the temperature in a pipe system or container during operation in °C or °F (if specified in Kelvin = T operation/0 °K = -273 °C) that is required in order to operate the plant. The operating temperature can, however, fluctuate within the system. For components and devices inside a plant, the so-called "maximum permissible operating temperature" (t operation max) is critical for the function. The temperature should not drop below this value (if specified by the manufacturer) and it must never rise above it. Its size is defined by the respective manufacturer. The interactions that occur with plastic in terms of temperature/pressure resistance mean that the standardized tables/diagrams must be observed.
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Is the temperature in a pipe system or container during operation in °C or °F (if specified in Kelvin = T operation/0 °K = -273 °C) that is required in order to operate the plant. The operating temperature can, however, fluctuate within the system. For components and devices inside a plant, the so-called "maximum permissible operating temperature" (t operation max) is critical for the function. The temperature should not drop below this value (if specified by the manufacturer) and it must never rise above it. Its size is defined by the respective manufacturer. The interactions that occur with plastic in terms of temperature/pressure resistance mean that the standardized tables/diagrams must be observed.
Optimum draining
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A term for the design and construction of a media-carrying component or plant section which enables the optimal draining of a pipe system without outside intervention. Complete draining is not possible in reality especially because the increased adhesion of a working medium leads to the medium sticking partly to the surfaces of the pipe sections, valves or vessels to be emptied.
Actually the optimisation of plant can merely ensure that an unhindered outlet can take place. Ideally no media residue in the form of puddles or clogged material remains in the pipe. To counteract an increased media adhesion it may be useful to fit transverse pipes and components with an appropriate drop/gradient. This is also recommendable to overcome gravity and define an orderly outlet in direction and time. See also Free outlet and Self-draining.
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Actually the optimisation of plant can merely ensure that an unhindered outlet can take place. Ideally no media residue in the form of puddles or clogged material remains in the pipe. To counteract an increased media adhesion it may be useful to fit transverse pipes and components with an appropriate drop/gradient. This is also recommendable to overcome gravity and define an orderly outlet in direction and time. See also Free outlet and Self-draining.
Osmosis
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Ozonization
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P-controller
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P1 – P4
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Packing material disinfection / packing material sterilisation
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Pasteurising
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Method for reducing the colony number. Products, e.g. foods are pasteurised by gentle heating and are therefore made germ-free.
A distinction is made product-specifically between 3 methods.
Low pasteurising: 30 min at 61.5 °C or continuous pasteurising 15 sec at 71.0 °C (HTST).
High pasteurising: Momentary temperature effects of 80 - 135 °C are used in continuous operation.
Long-term pasteurising: For deactivation of viruses in blood derivatives; treatment at 60 °C for 10 h.
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A distinction is made product-specifically between 3 methods.
Low pasteurising: 30 min at 61.5 °C or continuous pasteurising 15 sec at 71.0 °C (HTST).
High pasteurising: Momentary temperature effects of 80 - 135 °C are used in continuous operation.
Long-term pasteurising: For deactivation of viruses in blood derivatives; treatment at 60 °C for 10 h.
PE
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Permeation
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Pests
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pH value
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The pH value indicates how acidic or alkaline a liquid is. The scale ranges from 0 to 14 pH. The lower the pH value, the mor acidic the liquid. The higher the pH value, the more alkaline the liquid. Pure water has a pH value of 7. An increase from 7 to 8 corresponds to an increase of 10 times the starting concentration.
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Pharmacopoea(e)
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PIC
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PID-control
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Pigging
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Is the cleaning of a pipe with the help of a pig (cleaning device which fills out the entire tube cross-section). A pig is placed in the pipe. It is moved by additionally exerted pressure or by the flow generated by the medium. A pig can only be used if the line does not contain any valves.
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Piston slide valve
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Also: piston valve
A cylindrical piston is equipped with different channels and integrated mobile in a housing. By moving the piston in the housing the channels of the piston are brought into alignment with the connections in the housing. Paths can be cleared or blocked according to the position of the piston in this way. Piston slide valves can be used very well at high operating pressures and temperatures according to their design. Thanks to their simple structure piston slide valves are very suitable for multi-way applications. Their short travel stroke is usually actuated by electromagnets.
Areas of application: Use as a control/pilot valve in clean, contaminated, usually chemically inert or weakly corrosive liquid, gaseous media and steam. Particularly used as pilot valves in hydraulic and pneumatic systems. These valves were developed and used for steam power systems at the beginnings of industrialisation. A generally well known application is the control of steam power for the operating cylinder in steam engines. This type of valve is not found in process-technical circuits and within processes – but as pilot valves in their near vicinity for control and activation of cylinders and valve actuators.
Special features and advantages: Piston slide valves are usually used in very small and small nominal sizes. They can easily be made multi-way and are simple to install. They are suitable for high operating pressures and temperatures according to their design. In the versions for use in hydraulics and pneumatics the travels are very short so that they are actuated here by one or more electromagnets. They are therefore often referred to colloquially as solenoid valves. However, this is strictly incorrect and can lead to confusion with short-stroke globe valves.
Examples for areas of applications: Steam power controls (e.g. locomotives), hydraulic systems (e.g. mechanical engineering), pneumatic controls (e.g. mechanical engineering and plant engineering).
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A cylindrical piston is equipped with different channels and integrated mobile in a housing. By moving the piston in the housing the channels of the piston are brought into alignment with the connections in the housing. Paths can be cleared or blocked according to the position of the piston in this way. Piston slide valves can be used very well at high operating pressures and temperatures according to their design. Thanks to their simple structure piston slide valves are very suitable for multi-way applications. Their short travel stroke is usually actuated by electromagnets.
Areas of application: Use as a control/pilot valve in clean, contaminated, usually chemically inert or weakly corrosive liquid, gaseous media and steam. Particularly used as pilot valves in hydraulic and pneumatic systems. These valves were developed and used for steam power systems at the beginnings of industrialisation. A generally well known application is the control of steam power for the operating cylinder in steam engines. This type of valve is not found in process-technical circuits and within processes – but as pilot valves in their near vicinity for control and activation of cylinders and valve actuators.
Special features and advantages: Piston slide valves are usually used in very small and small nominal sizes. They can easily be made multi-way and are simple to install. They are suitable for high operating pressures and temperatures according to their design. In the versions for use in hydraulics and pneumatics the travels are very short so that they are actuated here by one or more electromagnets. They are therefore often referred to colloquially as solenoid valves. However, this is strictly incorrect and can lead to confusion with short-stroke globe valves.
Examples for areas of applications: Steam power controls (e.g. locomotives), hydraulic systems (e.g. mechanical engineering), pneumatic controls (e.g. mechanical engineering and plant engineering).
Pitting
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In pitting, the passive layer is punctured selectively at special points. Pittings or holes may occur in a steel surface. Pitting is caused particularly by chloride ions or bromide ions. If there is any pitting in a component, this cannot be halted by passivation because the corrosion product is mainly concentrated there and there is no oxidation possibility in the holes. Austenitic chrome-nickel steels are largely resistant to pitting, especially with increasing molybdenum content. The steel 1.4439 with a 4 – 5 % molybdenum is cited as an example here. But the surface also has an influence.
Electropolished surfaces, for example, have a greater resistance in the atmosphere than polished surfaces. A non-destructive test of the corrosion attack (depth) is not possible. Damaged surfaces should therefore always be repaired mechanically.
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Electropolished surfaces, for example, have a greater resistance in the atmosphere than polished surfaces. A non-destructive test of the corrosion attack (depth) is not possible. Damaged surfaces should therefore always be repaired mechanically.
Plant
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PLC
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Plug valve
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A (usually cone-shaped) rotating body incorporating a flow channel is turned by 90° in a valve body. According to the position of the rotating body in relation to the volumetric flow the valve is closed, partially open or open. It is sealed by the surface compression of the rotating body in the valve body. The choice of materials defines how tight the valve is. This gives a friction resistance and the torque necessary for moving the valve. Plug valves are quarter turn valves and therefore only suitable for low cycle duties – especially in view of the friction. Plug valves should only be used for clean or only slightly soiled media. In addition to straight-way valves, plug valves are also available in multi-way versions. Any direction of flow is normally possible. Plug valves are sometimes called rotary or swing body valves. Plug valves are the oldest type of quarter turn valves and are still used today in their original form (e.g. tap on a wine barrel). They are the predecessors of ball valves.
Areas of application: Only to be used with clean liquid and gaseous media and steam. Suitable for inert and corrosive media according to the material version and design features, especially for very high temperatures. The application limits are up to an operating temperature of 100 °C depending on the design. The flow characteristic is very good (but only fully open). Because of the high surface friction and the swivel movement, the valve is only suitable for low cycle duties however. In plastic only for simplest applications (rain butt), in metal for high temperature applications (rocket propulsion).
Special features and advantages: Simple design, few parts. However very prone to failure in case of soiling and high cycle duties. Probably the first functional principle for quarter turn valves – a relic of the past.
Examples for areas of applications: Chemical industry (USA – fast diminishing), engines, hot gas controls, taps for beer and wine barrels and rain butts.
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Areas of application: Only to be used with clean liquid and gaseous media and steam. Suitable for inert and corrosive media according to the material version and design features, especially for very high temperatures. The application limits are up to an operating temperature of 100 °C depending on the design. The flow characteristic is very good (but only fully open). Because of the high surface friction and the swivel movement, the valve is only suitable for low cycle duties however. In plastic only for simplest applications (rain butt), in metal for high temperature applications (rocket propulsion).
Special features and advantages: Simple design, few parts. However very prone to failure in case of soiling and high cycle duties. Probably the first functional principle for quarter turn valves – a relic of the past.
Examples for areas of applications: Chemical industry (USA – fast diminishing), engines, hot gas controls, taps for beer and wine barrels and rain butts.
PMA
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PN (pressure nominal)
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Is the pressure rating / the nominal pressure of a pressurized pipewortk component (e.g. pipe, fitting, pump, sensor, valve and so on). The pressure rating is a number without a unit and is standardized. Components, such as valve bodies, are assigned a PN by the manufacturer. The pressure rating specifies (a) the resistance of a component to pressure (the amount of pressure a component can safely withstand) and acts as a safety feature. The nominal pressure rating does not provide any information about the fuction of the device concerned (see EN 1333). The pressure rating assigned to a component must demonstrate the following minimum resistances to pressure in relation to tightness: 1.1 times the stated mominal pressure in the through flow and 1.5 times the PN in terms of external leak tightness. In addition to specifying the amount of pressure a component can safely withstand (a), the PN classification also stipulates a standardized geometry for pipe dimensions and pipe connections such as flanges. This ensures (b) that pipework components are fitted together in accordance with their nominal pressure ratings.
Standardized pressure ratings: PN 2.5, 6, 10, 16, 25, 40, 63, 100 and so on.
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Standardized pressure ratings: PN 2.5, 6, 10, 16, 25, 40, 63, 100 and so on.
Pneumatic/hydraulic control
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Position control
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Positioning element
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Preservation
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Preserving agents
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Pressure Equipment Directive
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The Pressure Equipment Directive regulates the safety regulations of pressure equipment in Germany. It converts the EU Pressure Equipment Directive into national law. Prerequisites for this are pressure equipment with CE marking, an EC declaration of conformity and operating instructions in German.
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Pressure jolt
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A pressure jolt occurs when a liquid flow is interrupted or built up abruptly. The energy of the liquid flow is transformed into a pressure or vacuum wave which results in a sudden pressure difference. Pressure jolts may be so great that pipes are ripped out of their anchoring or burst. In most cases the valves are also destroyed. See also Water hammer.
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Pressure, hydrostatic
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Process control
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Process control system
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Protein
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PTB
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Pure steam
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Pyrogen test
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