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Flow Research is conducting a new
study on the worldwide pressure
transmitter market, The World
Market for Pressure Transmitters, 5th Edition, to
determine the size of the pressure
transmitter market in 2018 and forecast.growth through 2023.
Our
last edition of this study, published in May 2015, found that pressure transmitter revenues had grown substantially during the previous five years.
We also learned that the total size of the worldwide pressure transmitter market was a little less than half the size of the worldwide flowmeter market in terms of
revenues. We believe that the size of the installed base together with recent networking innovations in the acquisition of process data are two of the major reasons why the pressure transmitter market is strong and will continue to hold its own within the instrumentation
world. And we look forward to bringing you the latest data to show you
exactly how fast the market is growing around the world, where it is
growing and why. To
make sure we are get the most complete picture possible, we are contacting all known manufacturers of pressure transmitters worldwide. We ask
them for detailed information about geographic segmentation, industries sold into, types of pressure transmitters sold, and many other product segments. You
can count on The World
Market for Pressure Transmitters, 5th Edition to:
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Determine worldwide and regional market shares for pressure transmitters in 2018
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Forecast market growth for each of the four types of pressure transmitters through 2023
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Identify the industries and applications where pressure transmitters are used,
focusing on high growth areas
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Provide average selling process for all types of pressure transmitters worldwide and by region
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Analyze the products from the main companies selling into the pressure transmitter market
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Offer strategies for success to manufacturers who sell into the pressure transmitter market
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Profile the main pressure transmitter suppliers
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Identify all of the factors causing the market to grow
Why we need
pressure transmitters
Pressure is one
of the most widely measured variables in the process industries.
In process control, pressure measurement occurs in a variety of
contexts, especially in measuring the pressure exerted by liquid, steam,
and gas. In the oil & gas industry, wellhead pressures are measured in
subsea and topside locations. Pressure
measurement is used for liquids in pipelines to help create a
liquid interface detector.
In water towers, pressure is measured to monitor and control water
levels. Pressure sensors are
used to monitor the water pipe pressure in automatic sprinkling systems.
One of the most common measurements is barometric pressure, which is
used to predict the weather. In fact, the idea of atmospheric pressure
plays an important role in pressure measurement by pressure
transmitters. Pressure transmitters
also have an important relation to three other widely measured variables: flow, level, and temperature. Differential pressure (DP) transmitters can measure both flow and level, and some pressure transmitters also utilize temperature sensors to measure process temperature. In some cases, this temperature measurement is combined with pressure and volumetric flow measurements to compute mass flow. Pressure
transmitters to the rescue
While
pressure sensors can detect variations in pressure by converting changes in
resistance or capacitance to electrical values, these electrical signals
are relatively weak -- they are not strong enough to be transmitted over
distances or sent to a controller that may be located far from the
pressure sensor. To accomplish
this, a pressure transmitter is required.
Pressure transmitters are typically made up of a pressure sensor, an amplifier or conditioning element, and an output signal. The output signal
transmits the pressure reading to a flow computer, controller, or distributed control system
(DCS). Pressure transmitters
also typically contain a display that shows the pressure value conveyed by
the pressure sensor and convert it into a standardized output, typically
either 4-20mA or a digital signal.
There are
four main types of pressure transmitters:
Absolute
pressure transmitters, which sense absolute pressure, are referenced to a
full vacuum. The pressure of the measured media is compared against the
reference pressure of an absolute vacuum in a sealed reference chamber. Absolute
pressure transmitters are used to measure pressures that are not influenced
by atmospheric pressures. Vacuum transmitters are often used where high
accuracy is required, such as low pressure
measurement of vacuum distillation columns.
Gauge
pressure transmitters, which sense gauge pressure, are referenced to
atmospheric conditions. Gauge pressure
transmitters are widely used in the process industries to measure the
pressures of liquid, gas, and steam.
Both
absolute and gauge pressure transmitters are growing in part by replacing
pressure gauges, switches, and transducers.
Pressure transmitters are more stable and reliable than pressure
transducers. As end users
increasingly automate their operations, and also build new plants, they are
more likely to choose pressure transmitters over pressure transducers.
Absolute and gauge pressure transmitters also have the advantage
that, unlike differential pressure transmitters used for flow, they do not
have another technology that is replacing them.
Differential
pressure (DP) transmitters measure the difference between two pressures.
They are used for both flow and level applications.
When used for flow applications, they measure the difference between
pressures on the upstream and downstream side of a constriction in the
pipe, called a primary element. This
difference in pressure is used to compute flowrate.
DP
transmitters have been used for more than 100 years to measure flowrate. Their
strong installed base gives them a pronounced advantage over other types of flowmeters
-- although they are being displaced in some applications by new-technology flowmeters
such as Coriolis and ultrasonic, especially when higher accuracy and greater reliability is
required.
Multivariable
pressure transmitters measure two or more process variables. In many cases, they measure volumetric flow, along with pressure and
temperature, and use these values to compute mass flow.
Multivariable transmitters are becoming more widely used for steam
and gas flow measurement. While
they are more expensive than single variable DP transmitters, they
typically cost less than buying a DP transmitter along with single
pressure and temperature transmitters.
Multivariable transmitters were first introduced in 1992 by Bristol
Babcock, now part of Emerson Process Management.
Pressure and how it's
measured
Pressure
is a state or condition we face everyday. We speak of being “under
pressure," and talking about putting pressure on another person or
situation. Fundamentally, the idea of pressure is the idea of the
continuous exertion of force. From a measurement perspective, pressure is
force per unit area.
Just as
there are many applications for pressure measurement, there are also many
different instruments used for pressure measurement. These include pressure gauges, pressure sensors,
and pressure
transducers, as well as pressure transmitters.
There are also specialized devices for measuring pressure extremes,
such as vacuum pressure.
Pressure
sensors
Pressure
sensors operate by sensing pressure and converting it into an electrical
quantity. Two of the main types
used are piezoresistive and capacitive.
Piezoresistive is the most commonly used.
Piezoresistive
materials change resistance to the flow of current when they are strained
or compressed. A piezoresistive
pressure sensor consists of a micro-machined silicon diaphragm that has a
piezoresistive strain gauge diffused into it.
The diaphragm is fused to a silicon or glass backplate.
The sensor contains resistors that are typically arranged in the
form of a Wheatstone Bridge Circuit. As
pressure increases on the silicon, it is more resistant to current passing
through it. As a result, the
output of the Wheatstone Bridge is proportional to pressure.
Capacitive
pressure sensors use a thin diaphragm as one plate of a capacitor.
This diaphragm is usually metal or metal-coated quartz.
The diaphragm is exposed to a reference pressure on one side and to
the process pressure on the other. Pressure
changes cause changes in the capacitance.
Pressure changes can be determined by monitoring the changes in
capacitance values.
Pressure
transducers
Pressure
transducers resemble pressure transmitters, but they are generally lower in
cost and smaller than pressure transmitters.
They often have loose wires at one end and do not perform at the
same level as pressure transmitters. Pressure
transducers are widely used in discrete industries such as automotive
and plastics. They are less
typically used in the process industries.
Pressure
gauges
Pressure
gauges are relatively inexpensive mechanical devices that, for the most
part, are read manually. One of
the most well-known types is called the Bourdon gauge, which was patented
in France
by Eugene Bourdon in 1849. In
1852, Edward Ashcroft bought the American rights to the design of the
Bourdon gauge and founded the Ashcroft Manufacturing Company to make
pressure gauges for steam engines. This
was the beginning of the company that is today known as Ashcroft, Inc.
The company is located in Stratford,
Connecticut
and still sells pressure gauges, along with a variety of other
products including pressure transducers and transmitters, pressure and
temperature switches, and test instruments.
Bourdon
gauges contain a thin-walled metal tube that is typically threaded into the
compartment whose pressure is being measured. As pressure increases in the tube, the tube begins to straighten. On
the other end of the tube is a lever system that contains a pointer.
As the tube straightens, the pointer moves around a dial, indicating
pressure in pounds per square inch (psi).
Common tube shapes include curved or C-shaped, spiral, and helical. This is a mechanical device that is manually read.
Another type of mechanical gauge that operates in a similar fashion
and also contains a pointer is called a diaphragm gauge.
Traditional
gauges such as the Bourdon and diaphragm gauges are sensitive to vibration
and condensation. Another type
is called a “filled” pressure gauge, and it is filled with a viscous
oil. This design has fewer
moving parts than the traditional pressure gauges, and is more reliable.
This design dampens pointer vibration and is not susceptible to
condensation.
Order
today Flow Research has been
researching pressure transmitters since 2004, so we can say with confidence that our proven approach
brings you the most complete, comprehensive, and current research possible.
Please check out our Proposal
and see for yourself!
Differential
Pressure Articles
Pressure
Articles
Links
to DP Transmitter Suppliers
The
World Market for Pressure Transmitters, 4th Edition
Released in May 2015
The
World Market for Pressure Transmitters, 3rd Edition
Released in August 2011
The
World Market for Pressure Transmitters, 2nd Edition
Released in October 2007
The
World Market for Pressure Transmitters, 1st Edition
2004 - Provides historical reference
The
World Market for Differential Pressure (DP) Flowmeters and Primary Elements
January 2007
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