A basic introduction to steam - flowmeter, debietmeter ... stoom voor... · A basic introduction to steam. FOR HOT, COLD, MOIST AND ... Making Steam. From a cold start, ... problem

A basic A basic introductionintroductionto steamto steam

FOR HOT, COLD, MOIST AND FOR HOT, COLD, MOIST AND DRY, FOUR CHAMPIONS FIERCE.DRY, FOUR CHAMPIONS FIERCE.STRIVE HERE FOR MASTERYSTRIVE HERE FOR MASTERY

Milton 1666

Steam Wonderful SteamSteam Wonderful SteamVery high heat contentVery high heat content

RecyclableRecyclable

Clean, non toxicClean, non toxic

BiodegradableBiodegradable

Easy to distributeEasy to distribute

Easy to controlEasy to control

Steam Wonderful SteamSteam Wonderful SteamThe magic of steam is that The magic of steam is that pressure and temperature are pressure and temperature are directly related, it is therefore directly related, it is therefore easy to control temperature by easy to control temperature by controlling pressure.controlling pressure.

It is the ideal way to provide It is the ideal way to provide exactly the right temperature and exactly the right temperature and thus deliver the right amount of thus deliver the right amount of energy for a wide number of energy for a wide number of applications.applications.

Steam Wonderful SteamSteam Wonderful SteamAn application demands a An application demands a precise temperature throughout precise temperature throughout the process.the process.

An example might be cooking An example might be cooking toffee in a cooking pan.toffee in a cooking pan.

Too cool and the toffee isnToo cool and the toffee isn’’t t cooked.cooked.

Too hot and the sugar will burn.Too hot and the sugar will burn.

Steam Wonderful SteamSteam Wonderful SteamA direct source of heat such as a A direct source of heat such as a gas flame would create hot gas flame would create hot spots.spots.


With a thermal fluid, oil, or hot With a thermal fluid, oil, or hot water, a temperature gradient water, a temperature gradient would exist across a heat would exist across a heat exchanger as the temperature exchanger as the temperature was given up.was given up.


With a thermal fluid, oil, or hot With a thermal fluid, oil, or hot water, a temperature gradient water, a temperature gradient would exist across a heat would exist across a heat exchanger as the temperature exchanger as the temperature was given up.was given up.

Steam provides the answer. If Steam provides the answer. If the process requires a precise the process requires a precise temperature, all that is required temperature, all that is required is to control the pressure is to control the pressure accuratelyaccurately..

Sensible Heat & Latent HeatSensible Heat & Latent HeatTo understand this relationship To understand this relationship between temperature and between temperature and pressure, one needs to pressure, one needs to understand the concept ofunderstand the concept of‘‘Sensible heatSensible heat’’ and and ‘‘Latent heatLatent heat’’

Sensible heat can be defined as Sensible heat can be defined as the energy required to raise a the energy required to raise a given mass of a liquid to itgiven mass of a liquid to it’’s s boiling point.boiling point.

Latent heat is the amount of Latent heat is the amount of energy required to change that energy required to change that same mass of liquid to a vapour.same mass of liquid to a vapour.

Sensible Heat & Latent HeatSensible Heat & Latent Heat

In simple terms, latent heat is In simple terms, latent heat is the energy required make the the energy required make the molecules of water overcome molecules of water overcome the mutual attraction that kept the mutual attraction that kept them together as a liquid. them together as a liquid.


The liberated molecules retain The liberated molecules retain this added latent energy only this added latent energy only giving the latent energy up as giving the latent energy up as the molecules come together as the molecules come together as water again.water again.


Water boils at 100 Celsius at Water boils at 100 Celsius at atmospheric pressureatmospheric pressure

The The ‘‘sensiblesensible’’ energy in the energy in the water at 100 Celsius at water at 100 Celsius at atmospheric pressure is 419 kilo atmospheric pressure is 419 kilo Joules per kilogram.Joules per kilogram.

419 kilo Joules per kilogram


The additional The additional ‘‘latentlatent’’ energy energy required to turn this boiling water required to turn this boiling water into the dry gas called steam is into the dry gas called steam is 2257 kilo joules per kilogram.2257 kilo joules per kilogram.

The total energy in the steam is The total energy in the steam is 2675 kilo Joules per kilogram.2675 kilo Joules per kilogram.


=2257 kilo Joules per kilogram

+419 kilo Joules per kilogram


The other major change in our The other major change in our kilo of water is that at 100 kilo of water is that at 100 Celsius it had a volume of just Celsius it had a volume of just over 1 litre.over 1 litre.

When converted to steam it has When converted to steam it has a volume of 1673 litres !.a volume of 1673 litres !.

1 kg

1673 ltr

1 kg

1 ltr


If the pressure is increased, it If the pressure is increased, it will require an increase in the will require an increase in the sensible heat, in order to liberate sensible heat, in order to liberate the molecules of water .the molecules of water .


At a 10 bar static pressure, At a 10 bar static pressure, waterwater’’s boiling point is 184 s boiling point is 184 Celsius, it would require a 782 Celsius, it would require a 782 kilo Joules of heat energy to kilo Joules of heat energy to bring it to boiling point and an bring it to boiling point and an additional 2008 kilo Joules of additional 2008 kilo Joules of energy to change it all into a dry energy to change it all into a dry saturated vapour.saturated vapour.

The total energy is 2790 kilo The total energy is 2790 kilo Joules per kilogramJoules per kilogram


=2008 kilo Joules per kilogram

+782 kilo Joules per kilogram


If only 90% of the extra energy is If only 90% of the extra energy is added, then only 90% of the added, then only 90% of the water will be turned into steamwater will be turned into steam


Remember that during this Remember that during this process of chemical change process of chemical change from a liquid to a vapour, our kilo from a liquid to a vapour, our kilo of water has remained at a of water has remained at a constant temperature.constant temperature.

Similarly, having produced a kilo Similarly, having produced a kilo of steam, it will remain at a of steam, it will remain at a constant temperature until we constant temperature until we have condensed all of the steam have condensed all of the steam back to water and extracted all back to water and extracted all of the latent heat.of the latent heat.


Control the pressure Control the pressure very accurately very accurately

The temperature also will be The temperature also will be controlled controlled very accurately.very accurately.


When the steam hits a cool When the steam hits a cool surface, the latent heat is given surface, the latent heat is given up and the steam turns back to up and the steam turns back to water water

The resulting condensate being The resulting condensate being returned to the boiler for rereturned to the boiler for re--use. use.



When steam as a dry vapour hits When steam as a dry vapour hits a hotter surface, then the steam a hotter surface, then the steam can get hotter than itcan get hotter than it’’s saturation s saturation temperature.temperature.

The result is superheated steamThe result is superheated steam

Superheated steam is most Superheated steam is most often produced by passing the often produced by passing the steam through a second heat steam through a second heat exchanger in the boiler.exchanger in the boiler.


Superheated steam will also be Superheated steam will also be produced if the pressure of dry produced if the pressure of dry saturated steam is reduced by a saturated steam is reduced by a restriction orifice or pressure restriction orifice or pressure reducing valve.reducing valve.


Superheated steam is desirable Superheated steam is desirable in power plant such as steam in power plant such as steam turbines and may be useful in turbines and may be useful in reducing condensate problems reducing condensate problems in distribution but is undesirable in distribution but is undesirable in heat exchange applications in heat exchange applications where it gives up itwhere it gives up it’’s s temperature more reluctantly temperature more reluctantly than saturated steam.than saturated steam.


Having used the latent heat of Having used the latent heat of the steam, we are left with the steam, we are left with condensate and itcondensate and it’’s sensible s sensible heat. heat.


The condensate drains into the The condensate drains into the steam trap where it is separated steam trap where it is separated from the steamfrom the steam


Condensate being released Condensate being released through a steam trap is at through a steam trap is at atmospheric pressure, itatmospheric pressure, it’’s s temperature will be 100 Celsius, temperature will be 100 Celsius, and it will contain 419 kJ/kg of and it will contain 419 kJ/kg of sensible heat.sensible heat.

100

100


If the condensate being released If the condensate being released through a steam trap is at 7 bar through a steam trap is at 7 bar gauge, itgauge, it’’s temperature will be s temperature will be 170 Celsius, and it will contain 170 Celsius, and it will contain 721 kJ/kg of sensible heat.721 kJ/kg of sensible heat.

170

170


When the condensate line on the When the condensate line on the other side of the steam trap is at other side of the steam trap is at atmospheric pressure, a kg of atmospheric pressure, a kg of condensate have a maximum condensate have a maximum temperature of 100 Celsius and temperature of 100 Celsius and can only contain 419 kJ/kg of can only contain 419 kJ/kg of sensible heat.sensible heat.

100

170


As the temperature drops to 100 As the temperature drops to 100 Celsius, the difference between Celsius, the difference between the sensible heat at 7 bar g, (721 the sensible heat at 7 bar g, (721 kJ/kg) and the sensible heat at 0 kJ/kg) and the sensible heat at 0 bar g (419 kJ/kg) i.e. 302 kJ will bar g (419 kJ/kg) i.e. 302 kJ will turn 12% of the boiling turn 12% of the boiling condensate back into steam.condensate back into steam.‘‘Flash SteamFlash Steam’’ 100

170


As the volume of a kg of steam As the volume of a kg of steam is roughly 1600 times greater is roughly 1600 times greater than a kg of condensate, the than a kg of condensate, the 12% by mass of flash steam will 12% by mass of flash steam will have a volume over 160 times have a volume over 160 times that of the 88% condensate. that of the 88% condensate. This frequently the cause of the This frequently the cause of the noise heard from pipework noise heard from pipework adjacent to steam traps. adjacent to steam traps.

100

170


Making SteamMaking Steam

Producing the steam for process Producing the steam for process applicationsapplications


Water from a feed tank is Water from a feed tank is pumped under pressure into the pumped under pressure into the steam boilersteam boiler


The level of the water in the The level of the water in the boiler shell will be controlled by boiler shell will be controlled by level controls or switcheslevel controls or switches


From a cold start, the boiler will From a cold start, the boiler will be be ‘‘firedfired’’ with the steam outlet with the steam outlet valves closed. valves closed.


First, the water is raised to First, the water is raised to boiling point at atmospheric boiling point at atmospheric pressure.pressure.


As the water boils the adding As the water boils the adding more heat causes bubbles of more heat causes bubbles of steam to form which float to the steam to form which float to the top and are released into the top and are released into the steam spacesteam space..


Because the outlet valve is Because the outlet valve is closed and because the closed and because the chemical change from a liquid to chemical change from a liquid to a vapour causes an expansion a vapour causes an expansion from 0.001 m3 per kilo to 1.673 from 0.001 m3 per kilo to 1.673 m3 per kilo. m3 per kilo.


With this change of volume as With this change of volume as water expands into steam, the water expands into steam, the pressure within the boiler will pressure within the boiler will start to rise and will continue to start to rise and will continue to increase until the pressure increase until the pressure controls on the boiler turn down controls on the boiler turn down the heat source.the heat source.


At this point, the boiler is fully At this point, the boiler is fully charged with steam at a charged with steam at a pressure of maybe around 10 pressure of maybe around 10 bar and a temperature of around bar and a temperature of around 200 Celsius.200 Celsius.


Downstream is a cold pipeline, Downstream is a cold pipeline, maybe with a little cold maybe with a little cold condensate left in.condensate left in.


Imagine the consequences if the Imagine the consequences if the boiler steam valve is opened up boiler steam valve is opened up too quickly and all the energy too quickly and all the energy within the boiler is suddenly within the boiler is suddenly released into the distribution released into the distribution system.system.


A good boiler operator will gently A good boiler operator will gently open the valve and allow the open the valve and allow the temperature to rise slowly to temperature to rise slowly to minimise thermal shock.minimise thermal shock.This procedure will allow This procedure will allow condensate which will be formed condensate which will be formed as the system warms up to be as the system warms up to be drained away. drained away.


Opening the valve too quickly Opening the valve too quickly could create sonic velocities could create sonic velocities within the pipeline.within the pipeline.A slug of condensate being fired A slug of condensate being fired down the pipeline at the speed down the pipeline at the speed of a bullet often has devastating of a bullet often has devastating effects.effects.


Once the distribution system is Once the distribution system is up to temperature, the steamup to temperature, the steam’’s s work can commence.work can commence.

Quality of SteamQuality of Steam

Boiler capacity, pipe sizing, good Boiler capacity, pipe sizing, good distribution system design are all distribution system design are all critical factors in the production critical factors in the production of good quality saturated steamof good quality saturated steam


If steam demand increases If steam demand increases beyond the capacity of the beyond the capacity of the boiler, the pressure drops, the boiler, the pressure drops, the size of the steam bubbles size of the steam bubbles increases forcing the apparent increases forcing the apparent water level to rise within the water level to rise within the boiler.boiler.


With a subsequent reduction in With a subsequent reduction in steam space and greater surface steam space and greater surface turbulence, the larger bubbles turbulence, the larger bubbles splash out of the water surface splash out of the water surface throwing water droplets into the throwing water droplets into the steam.steam.The increased velocity out of the The increased velocity out of the boiler will carry many of these boiler will carry many of these droplets into the distribution droplets into the distribution system reducing steam quality.system reducing steam quality.


Within the distribution system Within the distribution system some heat energy will be lost in some heat energy will be lost in the pipelines creating the pipelines creating condensate.condensate.


The distribution pipework must The distribution pipework must be of adequate size such that be of adequate size such that any water carried over and or any water carried over and or condensate forming from the condensate forming from the steam as a consequence of heat steam as a consequence of heat loss from the pipes is not picked loss from the pipes is not picked up by excess pipeline velocity up by excess pipeline velocity and carried in the steam.and carried in the steam.


Velocities in excess of 40 metres Velocities in excess of 40 metres per second are likely to cause per second are likely to cause reduced steam quality due to the reduced steam quality due to the increased water droplets in increased water droplets in suspension. suspension.

Water droplets flying down a Water droplets flying down a pipe line at say 50 metres per pipe line at say 50 metres per second ( 120 miles an hour ) second ( 120 miles an hour ) continuously are bound to cause continuously are bound to cause wear and erosion.wear and erosion.


Most authorities consider that a Most authorities consider that a steam velocity of 25 to 35 steam velocity of 25 to 35 metres per second provides for metres per second provides for acceptable pressure drop, acceptable pressure drop, acceptable heat loss, and acceptable heat loss, and minimum pick up of condensate. minimum pick up of condensate.

This velocity may be reduced to This velocity may be reduced to minimise pressure loss where minimise pressure loss where distribution lines are very long.distribution lines are very long.


Good design of the distribution Good design of the distribution system with particular attention system with particular attention to drainage improves steam to drainage improves steam quality dramatically.quality dramatically.

For efficiency and safety it is For efficiency and safety it is vital that all condensate is vital that all condensate is removed from the distribution removed from the distribution mains as quickly as possible.mains as quickly as possible.


Lines should have a fall in the Lines should have a fall in the direction of flow, typically 20 mm direction of flow, typically 20 mm per 10 meters of pipe, have per 10 meters of pipe, have collecting legs every 40 to 50 collecting legs every 40 to 50 metres and no untrapped low metres and no untrapped low points where water can collect.points where water can collect.

1 in 500


Low points and collecting legs Low points and collecting legs should be fitted with steam traps. should be fitted with steam traps. In their most simple form, steam In their most simple form, steam traps allow the passage of water traps allow the passage of water to drain but wonto drain but won’’t allow steam to t allow steam to pass. pass.

In most modern distribution In most modern distribution systems the condensate and itsystems the condensate and it’’s s sensible heat will be returned to sensible heat will be returned to the plant room and used again the plant room and used again for the production of steam.for the production of steam.

Quality of SteamQuality of SteamBefore we leave the subject of Before we leave the subject of distribution lines and trapping. On distribution lines and trapping. On some systems there can be a further some systems there can be a further problem during that start up from cold. problem during that start up from cold. The condensate pipe may not self drain The condensate pipe may not self drain back to boiler feed tank. It may require back to boiler feed tank. It may require some pressure in the steam line to some pressure in the steam line to force the condensate through the force the condensate through the steam trap. As the system is being steam trap. As the system is being primed slowly it may be same time primed slowly it may be same time before that pressure is available, at the before that pressure is available, at the same time we are producing large same time we are producing large quantities of condensate which canquantities of condensate which can’’t t get away. Even with a gentle start up get away. Even with a gentle start up there could still be some water hammer there could still be some water hammer as condensate gets pushed through the as condensate gets pushed through the system.system.


Branch lines should always be Branch lines should always be connected to the top of the connected to the top of the steam main to provide the driest steam main to provide the driest steam to the process.steam to the process.


Distribution lines should be well Distribution lines should be well insulated to minimise the amount insulated to minimise the amount of condensate being formed of condensate being formed (and to save energy).(and to save energy).


Imagine standing water in a low Imagine standing water in a low point in the pipe. The demand is point in the pipe. The demand is low so the steam passes easily low so the steam passes easily over the standing water. over the standing water.


Demand increases, the resulting Demand increases, the resulting increased velocity starts to push increased velocity starts to push the water into a plug.the water into a plug.


This plug which possibly weighs This plug which possibly weighs several kilos gets larger as it several kilos gets larger as it picks up more of the condensate picks up more of the condensate in the line may be travelling in the line may be travelling down the pipeline at around 90 down the pipeline at around 90 miles per hour.miles per hour.

The impact caused by the kinetic The impact caused by the kinetic energy can be sufficient to bend energy can be sufficient to bend the spindles of valves, break the spindles of valves, break joints, and definitely cause joints, and definitely cause mischief with flowmeters.mischief with flowmeters.


Standing water in distribution Standing water in distribution pipework may not only be as a pipework may not only be as a result of a low section of pipe.result of a low section of pipe.

Badly installed pipe fittings, Badly installed pipe fittings, strainers, valves, and flowmeters strainers, valves, and flowmeters may all contribute. may all contribute.


Strainers & Globe valves should Strainers & Globe valves should be fitted on their side to prevent be fitted on their side to prevent damming of the flow.damming of the flow.

This example also shows that This example also shows that the strainers efficiency is the strainers efficiency is reduced by being waterlogged reduced by being waterlogged


The damming effect of of a The damming effect of of a concentric reducing fitting.concentric reducing fitting.

The benefit of an eccentric The benefit of an eccentric reducing fitting. reducing fitting.


Orifice plates as well as causing Orifice plates as well as causing a damming effect will be totally a damming effect will be totally ineffective for measurement.ineffective for measurement.

A drain hole in the bottom cures A drain hole in the bottom cures the problem and the change in the problem and the change in coefficient of discharge can be coefficient of discharge can be allowed for.allowed for.


Pressure reducing valves and Pressure reducing valves and steam control valves must steam control valves must always be preceded by a drain always be preceded by a drain leg.leg.Better still is the installation of a Better still is the installation of a proprietary steam separator proprietary steam separator which is designed to remove any which is designed to remove any water droplets suspended within water droplets suspended within the steam flow which would the steam flow which would cause erosion of the valve seats. cause erosion of the valve seats.

Steam TerminologySteam TerminologyMassMass ‘‘MM’’ is the quantity of steam by weight in kgsis the quantity of steam by weight in kgsDensityDensity ‘‘pbpb’’ is the mass per unit of volume kg/m3 at reference conditionsis the mass per unit of volume kg/m3 at reference conditions

‘‘pfpf’’ is the mass per unit of volume kg/m3 at flow conditionsis the mass per unit of volume kg/m3 at flow conditionsSpecific VolumeSpecific Volume ‘‘VbVb’’ is the volume per unit of mass m3/kg or dm3/kgis the volume per unit of mass m3/kg or dm3/kg

at reference conditionsat reference conditions‘‘VfVf’’ is the volume per unit of mass m3/kg or dm3/kgis the volume per unit of mass m3/kg or dm3/kg

at flow conditionsat flow conditionsPressurePressure ‘‘PbPb’’ is the pressureis the pressure kPa or bar at base conditionskPa or bar at base conditions

‘‘PfPf’’ is the pressure is the pressure kPa or bar at flow conditions kPa or bar at flow conditions Mass flowrateMass flowrate ‘‘QmQm’’ is the mass flowrate kg/hris the mass flowrate kg/hrEnthalpyEnthalpy ‘‘hbhb’’ is the specific enthalpy kJ/kg at reference conditionsis the specific enthalpy kJ/kg at reference conditions

‘‘hbhb’’ is the specific enthalpy kJ/kg at reference conditionsis the specific enthalpy kJ/kg at reference conditionsFlowmeterFlowmeter ‘‘KfKf’’ is the Kis the K--factor (vortex) pulses/m3factor (vortex) pulses/m3

‘‘SvSv’’ is the 20 mA span (vortex) m3/hris the 20 mA span (vortex) m3/hr‘‘SmSm’’ is the 20 mA span (DP) kg/hris the 20 mA span (DP) kg/hr

Steam TablesSteam TablesSteam tables are the most convenient way of showing the Steam tables are the most convenient way of showing the properties of steam. Unlike ideal gas, the properties of steam properties of steam. Unlike ideal gas, the properties of steam are not linear to changes in pressure or temperature.are not linear to changes in pressure or temperature.A typical dry saturated steam table will look something like A typical dry saturated steam table will look something like this.this.

Pressure Temperature Pressure Temperature Enthalpy Enthalpy DensityDensityGauge Absolute Water EvaGauge Absolute Water Evaporation Steamporation Steam

barbar barbar CelsiusCelsius kJ/kgkJ/kg kJ/kgkJ/kg kJ/kgkJ/kg m3/kgm3/kg33 4.0134.013 143.75143.75 605.3605.3 2133.42133.4 2738.72738.7 0.4610.46155 6.0136.013 158.92158.92 670.9670.9 2086.02086.0 2756.92756.9 0.3150.315

1010 11.01311.013 184.13184.13 781.6781.6 2000.12000.1 2781.72781.7 0.1770.1771515 16.01316.013 201.45201.45 859.0859.0 1935.01935.0 2794.02794.0 0.1240.124

MeteringMeteringRegardless of the chosen method of steam flow Regardless of the chosen method of steam flow measurement, steam quality plays a major part in the metermeasurement, steam quality plays a major part in the meter’’s s performance.performance.The steam should be dry and the pipeline free of The steam should be dry and the pipeline free of condensate.condensate.Wet steam will cause erosion particularly to orifice plates.Wet steam will cause erosion particularly to orifice plates.Wet steamWet steam’’s increased density will cause errors with DP type s increased density will cause errors with DP type meters. meters. Wet steam has more sensible heat per unit of volume and Wet steam has more sensible heat per unit of volume and less latent heat per kilo of mass.less latent heat per kilo of mass.Condensate could block the sensing holes on pitot tubes.Condensate could block the sensing holes on pitot tubes.With the high velocities associated with Vortex meters, any With the high velocities associated with Vortex meters, any condensate not drained upstream will almost definitely be condensate not drained upstream will almost definitely be come entrained into the steam flow.come entrained into the steam flow.

MeteringMeteringPipeline considerations.Pipeline considerations.

Most principles of steam metering require a good velocity Most principles of steam metering require a good velocity profile. profile.

The velocity profile will be affected by bends, valves, tees, The velocity profile will be affected by bends, valves, tees, reducers and the often forgotten friction due to roughness of reducers and the often forgotten friction due to roughness of the pipe wall. It is also vital that the pipe internal diameter the pipe wall. It is also vital that the pipe internal diameter is is correct for the meter being used. correct for the meter being used.

MeteringMeteringMethods of steam measurementMethods of steam measurement

Orifice plateOrifice plate (only dry steam)(only dry steam)ISA of long radius nozzleISA of long radius nozzle (dry and wet steam)(dry and wet steam)PTCPTC--6 nozzle6 nozzle (technically best option)(technically best option)Venturi nozzle/classical venturiVenturi nozzle/classical venturi (dry and wet steam)(dry and wet steam)PitotPitot tubetube (only monitor function)(only monitor function)Target meterTarget meter (not a serious option)(not a serious option)Variable areaVariable area (not a serious option)(not a serious option)Spring loaded variable areaSpring loaded variable area (is an option, mechanical(is an option, mechanical……))Turbine meterTurbine meter (not recommended)(not recommended)Vortex meterVortex meter (dry steam, good option)(dry steam, good option)Ultrasonic flowmeterUltrasonic flowmeter (option for larger pipes, HP)(option for larger pipes, HP)

MeteringMeteringAn alternative to the measurement of the steam is to An alternative to the measurement of the steam is to measure the boiler feed water or condensate return.measure the boiler feed water or condensate return.

Boiler feed.Boiler feed.High accuracy at point of measurement but allowance must High accuracy at point of measurement but allowance must be made for be made for ‘‘blow downblow down’’ of boiler and for any water droplet of boiler and for any water droplet carry over.carry over.

Condensate return.Condensate return.High accuracy but condensate must be free of any flash High accuracy but condensate must be free of any flash steam.steam.Ideal for measuring consumption of a single appliance Ideal for measuring consumption of a single appliance

MeteringMeteringSecondary InstrumentationSecondary InstrumentationAny primary flow meter is only as good as the Any primary flow meter is only as good as the instrumentation used to process or display the flow signal.instrumentation used to process or display the flow signal.In virtually all applications a flow computer should be used to In virtually all applications a flow computer should be used to compensate for any variations in density.compensate for any variations in density.With saturated steam it is only necessary to use either a With saturated steam it is only necessary to use either a pressure input or a temperature input. pressure input or a temperature input. With superheated steam, both pressure and temperature With superheated steam, both pressure and temperature inputs should be used.inputs should be used.Some principles of meter will benefit from Some principles of meter will benefit from linearisationlinearisation by the by the flow computer. flow computer.

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A basic introduction to steam - flowmeter, debietmeter ... stoom voor... · A basic introduction to steam. FOR HOT, COLD, MOIST AND ... Making Steam. From a cold start, ... problem