Archive for the ‘Pressure measurement’ Category

Who says there’s no innovation in water?

May 20, 2015

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Whole Government reports have been devoted to the subject of innovation in the UK water industry. The general gist is that, despite all of the money and effort that has gone into upgrading the UK’s water infrastructure since the industry was privatised 25 years ago, much more needs to be done to encourage the uptake of new technologies that could help to improve overall operational efficiency.

This situation looks to change with the introduction of TOTEX (TOTal EXpenditure). With its focus on total life expenditure and holistic network performance, TOTEX looks set to provide a fertile environment for innovation, as companies evolve to develop their understanding of their existing asset base. In particular, TOTEX replaces the previous CAPEX/OPEX focus on ‘outputs’ with an ‘outcome’-led approach, which places a much greater emphasis on achieving and demonstrating asset and network effectiveness.

Whilst embracing innovation may well have been lacking amongst water operators, the supply chain at least appears to be ahead of the game. This was particularly apparent at the recent IWEX exhibition at the Birmingham NEC, where suppliers of technology, expertise and water-related services presented their latest offerings.

Taking ABB’s exhibition stand as a starting point, visitors were shown the latest examples of the latest instruments, analysers, drives and motors for potable and wastewater applications. Several of these represent cutting edge developments. Our AquaMaster 3 flowmeter for example, is the first in the world to combine integrated flow and pressure measurement in a single device. It is also the first to feature WITS DNP3 technology, which allows operators to gain, via GPRS communications, unprecedented access to a range of performance data, including diagnostic data on the status of the meter itself.

We also had the first in our range of digital optical sensors, which use the latest advances in optical measurement technology to deliver stable and accurate measurement whilst maintaining calibration without drift.

Both of these instruments are good examples of the type of equipment that can be used to deliver the big data from a network that can be turned into information and used as the basis for operational decision-making in a TOTEX environment.

Energy and maintenance form another crucial part of the TOTEX equation, with savings in either area making an obvious contribution to reducing overall lifetime costs. Again, ABB’s stand provided examples of some of the latest thinking in this area, including our SynRM (synchronous reluctance motor) and drive package for the water industry. Offering good partial load efficiency performance for all pumping applications, the package combines the benefits of a premium motor control with the highest levels of motor performance, giving ultimate efficiency and reliability to optimise pump system cost of ownership.

ABB’s stand was just one of dozens representing the latest developments in technology, spanning all aspects of the potable and wastewater treatment cycles.

In short, the innovation to help water companies transform their network performance is definitely out there. The challenge now is to move beyond a short term cost focus, which has too often led to the selection of the cheapest cost rather than the best value solutions, and work with suppliers to see what they can really offer.

If you’d like to find out more about how measurement instrumentation can be used to help you meet your TOTEX targets, why not request a copy of our new white paper ‘The role of performance data in optimising assets under TOTEX’. For a copy, email: moreinstrumentation@gb.abb.com or call 0870 600 6122 ref. ‘TOTEX’.

Are you keeping up to date with MCERTS?

March 19, 2010

                                                                                 

 Tony Hoyle, Flow Products Manager, ABB Limited, asks if UK companies are sufficiently prepared to meet MCERTS requirements

So you’ve installed the equipment, taken the necessary measures and passed your first MCERTS inspection. Congratulations. Time to sit back and relax? Not if you want to successfully pass your next one…

For those who aren’t yet familiar with it (and you really should be if it applies to your process), MCERTS is the Environment Agency’s (EA) certification scheme to ensure your company has effective measures in place to monitor its effluent flows. Both industrial and water utility sites need to meet MCERTS requirements whenever their discharges must be monitored and controlled as part of their permits under the Environmental Permitting Regulations (EPR), previously known as the Pollution Prevention and Control (PPC) regulations. 

In its quest for thoroughness and consistency, MCERTS covers not just the technology used on your site, but also, through the Operator Monitoring Assessment (OMA) scheme, the competence of any operational staff responsible for maintaining or using it.

A key thing to remember is that your Site Conformity Inspection Certificate is only an indication of your site’s compliance on the actual date of inspection, Technology can wear out or become outdated and people can leave, fail to maintain their training or lapse into bad habits.

Furthermore, the key thing about MCERTS is that it is a continually evolving standard, with new requirements being added all the time such as the latest version of the Operator Monitoring Assessment standards.

The fact that your certificate lasts for five years could therefore actually lull you into a false sense of security. You should be using this intervening time to ensure that you’re using the latest Best Available Techniques (BAT) and that your staff are kept properly trained and are following a robust maintenance regime.

Luckily, whatever you may think of the MCERTS scheme, the Environment Agency is not there to catch companies out. You now have the option of having your site and operating procedures inspected up to a year in advance of the expiry of your certificate. If you pass, your new certificate will cover you for five years from the date your old certificate expires. If you fail, you’ll be expected to take remedial actions in time for your site to be recertified.

When it comes to measurement of effluent flows, ABB can also assist with achieving MCERTS compliance for your metering systems. Our support ranges from a simple annual meter verification through to facilitating the actual MCERTS inspections. We offer tailored support packages to ensure you have all the documentary evidence for a sound maintenance programme, which meets UK regulations. 

     

So as you can see, it pays not only to keep up to date with MCERTS, but actually to get ahead of it and identify anything that could potentially jeopardise your next inspection.

If you want to find out more about keeping up to date with MCERTS, I will be presenting a seminar on this topic at IWEX on Thursday 22nd April at 13:30. You can find further information at  www.sustainabilitylive.com/page.cfm/action=Seminars/SeminarID=151.

 

Top tips for pressure transmitter selection

November 4, 2009

Les Slocombe, Pressure Temperature UK Business Manager at ABB Instrumentation, gives his top tips on how to choose the right pressure transmitter for the job at hand.

The variety of potential applications and installation locations for pressure measurement means that it’s difficult to set any hard and fast rules. At ABB Instrumentation we have developed six top tips to help you shape and narrow down the choice of pressure measurement device for your application.

1. Transducers or transmitters?

Many people give confused over the difference between these two devices.

A transducer creates a low-level electronic signal in response to changes in applied or differential pressure and features an internal sensor that converts the applied force into an electric signal, from which the measurement is derived. Transducers are generally unsuitable for the harsh environments typical of many industrial applications as they are poorly protected against the effects of overpressure or damage caused by sudden variations in process conditions.

Transducers also have inferior stability and measurement accuracy compared to transmitters. They offer limited compensation for variations in process or ambient conditions such as temperature and are often fixed range devices, which can only measure within a set span.

Transmitters for measuring pressure or differential pressure, on the other hand, comprise two basic parts. A primary element directly or indirectly in contact with the process collects the measurement, while a secondary electronics package translates the output from the primary element into a standard 4-20mA dc output signal.

These secondary electronics are highly sophisticated and perform many functions that transducers cannot. Variations in process or ambient conditions measured by the primary sensor can be automatically compensated for before being converted into a 4-20mA signal.

This minimises unwanted measurement errors and gives the transmitter a very stable output. Operators can also calibrate the transmitter over a range of input pressures, enabling one unit to be used to measure a range of spans.

2. Consider your operating environment

Modern pressure transmitters should be able to comfortably handle adverse temperatures, humidity and vibration conditions provided they are within design specification limits. Minimising the effects of such conditions will help to maximise the transmitters operational life.

  • Temperature

Most electronic transmitters are suitable for conditions ranging from lows of  –20°C to –40°C to highs of 60°C to 85°C, although this may not always be the case for certain types, for example where special filling materials have been specified for the transmitter. An application’s ambient temperature conditions can significantly affect transmitter efficiency; high temperatures can have a detrimental effect, potentially causing premature component failure. Ideally, the temperature of the transmitter should be kept as low as possible for maximum life expectancy.

Careful consideration also needs to be exercised when installing a transmitter outdoors. Atmospheric conditions such as direct sunlight or high winds can cause heating or cooling of transmitters, which can adversely affect their operation.

  • Humidity

Vapour caused by humid conditions can sometimes penetrate the transmitter housing and attack sensitive components. Prolonged exposure to high humidity can also result in corrosion of the transmitter housing and mountings. Transmitter housings are designed to protect electrical components against the ingress of moisture caused by humidity.

Some manufacturers employ various methods such as using potting material to protect transmitter electronics against humidity. Whilst they can delay humidity problems, these methods do not provide a long-term solution. The only true prevention against humidity is for the transmitter housing to be hermetically sealed.

  • Vibration

Avoid installing a transmitter in an area subject to prolonged or unnecessary levels of vibration, as this can reduce the service life of the transmitter. To protect against potential damage or malfunction caused by vibration, transmitters should be mounted in a location that will be unaffected by vibration when a process is in operation.

 3. Two wire, four wire or digital?

 There are many different types of transmitters, each of which use different techniques to transmit a signal. The role of the transmitter is to amplify and condition the signal so that it can be relayed over long distances to devices such as indicators, recorders and controllers without deterioration or interference.

 For the majority of applications where power is readily available, the two-wire transmitter, which uses a 4-20mA current both to operate its circuitry and to relay a signal, is often the most practical choice. Because the current is protected against the effects of changing resistance along the line, signals can be relayed over long distances.

For applications where a ready supply of power is not available, such as remote installations, then a low powered four-wire electronic transmitter is the best choice.

Four-wire devices use two wires to power the instrument and two wires to transmit the signal. These low powered transmitters typically consume about one-tenth of the energy of standard two-wire transmitters under normal operating conditions. Despite consuming less energy, they are only really suitable for applications where the devices to which they are to be connected are close by. This is because long transmission distances produce a loss of voltage signal due to the internal resistance drop in the line, affecting measurement accuracy.

Where high-speed transmission of accurate data is essential, the best choice is to opt for digital transmitters, which transmit both digital and analogue signals via a two-wire link. Digital signal transmission is faster and more accurate than analogue and allows much more data to be relayed between the instrument and the control room.

ABB’s pressure transmitters are available with a choice of communications standards including HART/4-20 mA, Profibus, Modbus and Foundation Fieldbus. All ABB pressure measurement equipment is also based on ABB’s IndustrialIT platform, enabling it to be used with other ABB IndustrialIT enabled products to form part of a complete process system.

4. Is the application hazardous?

Any electronic instrument either stores electrical energy or is a source of electrical energy. In certain conditions, this energy, if discharged could ignite any accumulated mixtures of flammable gases, combustible dusts and ignitable fibres that may be present.

Caution needs to be exercised when locating any electronic pressure transmitter in a hazardous or potentially hazardous location.

The recently introduced ATEX Directive sets out various measures for assessing the risk posed by hazardous environments and the steps that need to be taken to minimise the risk of ignition.

There are three main approaches that can be taken when installing a pressure transmitter in a potentially hazardous area. The first is to locate the transmitter in a safe area, where there are no ignitable gases or combustible dusts present. A remote seal is then used to perform the sensing in the hazardous area. This prevents the device’s energy source from being in the hazardous area.

The second approach is to specify a transmitter with an explosion-proof housing, which can contain the ignition source and prevent it from discharging outside of the device.

The third, and potentially best approach, is to use an intrinsically safe pressure transmitter device. These instruments do not have sufficient energy to cause ignition, making them ideal for use in hazardous locations. 

ABB’s Safety Pressure Transmitters provide a single range of pressure measurement devices for hazardous applications that call for SIL2 and SIL3 integrity, such as in the chemical, petrochemical, pharmaceutical and oil and gas industries. In a SIL2 environment, a single safety transmitter can provide the same level of protection as two conventional devices, eliminating the need for two devices and effectively reducing operating and lifecycle costs by 50%.

 5.   Do you need a remote seal?

Remote seals are used to isolate pressure transmitters from conditions that will either shorten their operational life or dramatically affect their performance. Comprising a transmitter body, a capillary and a seal element incorporating a liquid filled diaphragm, remote seals are ideal for a range of pressure measurement applications involving process fluids which are:

  • Highly corrosive
  • Dirty, viscous or laden with solids that can block or foul the impulse lines
  • Likely to solidify in the impulse lines or the transmitter body
  • Too hazardous to enter the control area where the transmitter is located

 Remote seal transmitters can also provide an ideal solution for hygienic processes, such as in the pharmaceutical and food and beverage industries, where it may be undesirable to have a pressure measurement device in direct contact with the product.

 6.    What else do you want to measure?

 For certain applications involving the measurement of gases or fluids subject to rapid density changes, it may be advantageous to use a multivariable pressure transmitter device. These devices offer a three-in-one solution for the measurement of flows of liquids, steam or gas with absolute pressure and temperature compensation, ideal for calculating changes in flow density.

Previously, the main method of calculating flow density involved deriving measurements against known standard conditions. Though fine for applications with constant or relatively minor deviations in process conditions, this approach is less effective for installations where high accuracy measurement is required or where fluctuations in the flow medium are likely to occur.

For ABB’s multivariable transmitter, the combination of three different measurements into one device enables users to select appropriate accuracies for their applications ranging from 0.04% to 0.075%.

Incorporating three different forms of measurement into one unit can also significantly reduce installation costs savings on installation through the need for fewer devices and a reduction in the amount of cabling and I/O devices required.

Although there is a lot to take on board in these top tips bearing all these factors in mind when specifying a pressure measurement device is a guaranteed way to ensure you select the right transmitter for the job!”