Measurement and Testing 41
Excellent Measurement Accuracy in Airport’s Critical API Hydrocarbon Separator Unit
Pulsar Process Measurement (UK) have supplied a non-contacting ultrasonic open channel flow measurement system featuring their DUET transducer array to give excellent measurement accuracy in the airport’s critical API hydrocarbon separation unit. Pulsar’s FlowCERT system featuring the DUET transducer has achieved Class 1 MCERTs certification.
Surface water runoff in an area as large as a major airport is considerable, and in certain areas may be mixed with aviation fuel, oil and other contaminants, so it has to be treated in the same way as any other industrial effluent before it can be discharged. That means separation, treatment and measurement of the final effluent flow, which is where Pulsar comes in.
Pulsar supplied a v-notch weir plate along with a DUET transducer array and FlowCERT control unit to measure effluent flow through an open channel. As can be seen in the picture, the channel was in an exposed position, where solar radiation can be a significant factor affecting the accuracy of the measurement. The v-notch weir plate was sized for a maximum flow rate of 25 litres per second, although the actual flow can be very small indeed in dry periods of the year. It is vital that the measurement remains reliable and accurate. The measurement of this type of application is particularly difficult; the ultrasonic technique is based on the measurement of the time taken for an echo to return to the face of a transducer, which is in turn dependent on the speed of sound. The speed of sound in air varies with air density, which is affected by air temperature. If the measurement device does not compensate quickly and accurately, errors are introduced into the result. In this case, because the head varies by around 200mm between high flow and zero, it is crucial that the measurement is accurate and repeatable right down to the very lowest flows, and records a genuine zero when there is no flow at all.
DUET is perfect for this type of application, consisting as it does of an array of two transducers that fire ultrasonic pulses simultaneously, which are then received at the lower transducer only. The FlowCERT controller then compares the two returning echoes. The two transducers are mounted on a heavy frame and the separation of the two transducers is a fixed distance, so any changes in the measured distance when comparing the two ultrasonic pulses must be down to variations in the speed of sound. This strategy allows the FlowCERT controller to compensate dynamically and accurately for these variances, applying that compensation to the flow measurement. Under MCERTs tests, this unique system has allowed FlowCERT and DUET to achieve industry-leading total error levels of only 0.037%, even under the new, stringent, solar radiation test.
As Mark Stewart, the Airport’s Water Services Engineer in charge of the project, put it: ‘We were very pleased with the way that Pulsar responded to the project brief, and have been delighted with the performance of the DUET. We’re confident about the measurement, so we know we are submitting exactly the right figures to the EA. We’re now in the process of standardising on Pulsar equipment for all our flow and level measurement applications’.
Reader Reply Card No New High Temperature Hydrocarbon Analyser
Baseline-Mocon, Inc., (USA), a subsidiary of Mocon, announces the release of their new heated hydrocarbon analyser for applications that require the sample to stay heated above its dew point.
135 Planning on Board
In this computer age surely manual planning boards and T- card systems disappeared with flairs and tank tops? They did. Planning boards were replaced by software systems but they have now returned in surprising volumes playing a changed role by working alongside and supporting computer systems. Visit any office or factory and you will see whiteboards or paper charts displaying information alongside the computer. These are forms of planning boards. We all plan with computers. They provide task loading schedules to ensure accurate and current compliance situations.
However, we still lack that essential summary or complete overview of a schedule and scrolling or outdated printouts are of no use to the modern manager. He requires a ‘big picture’ of his total plan that is totally visual and simply updated. It must provide a summary of the current situation, highlighting spare capacity or possible bottlenecks and predicting the consequences of any change to plan. Perfect for group discussions and team meetings. The supply of accurate data to the computer master plan often depends on a sub-level supplement of factory or office manual planning systems.
These are sometimes mistakenly viewed as a
backward step by computer blinkered management but play a vital role in ensuring the computer performs to its maximum effect. After all,information is more valuable when it is accurate and current. Best Practice, Lean Management, Continuous Improvement and Kanban Production management methods demand the display of ‘must see’ information. These may take the form of factory floor workstation displays, planning room management systems or rapidly updated information display boards. These are all part of the new planning board role.
Eurocharts (UK) are leading planning systems specialists Who have been in operation for over 25 years and have played an integral role in the transitional move of the planning board to a computer support product. Requirements vary and Eurocharts have launched possibly the UK’s only planning board systems specialist catalogue. This features familiar old friends like T-card systems but also introduces new kit and bespoke project and production systems, magnetic scheduling boards, Kanban production systems and Lean Management visualisation boards and products. Eurocharts provide samples and operate a Free Planning Advisory Service involving telephone and email assistance or on-site visits to help with any planning system design.
Reader Reply Card No 137
Configured for single point analysis, the
Series 9000 H Heated Hydrocarbon Analyser has an active range from less than 30 ppb as methane with the high sensitivity version and up to 50% as methane with the percent level version. Standard outputs include alarm and fault relays, 0-20mA / 4-20mA analog, or the recommended digital options, RS-232 or ethernet.
Applications for the Series 9000 H include continuous emission monitoring (CEM), scrubber & oxidiser efficiency, carbon bed breakthrough detection, LEL monitoring, vehicle emissions, chemical process blending, and compliance monitoring for EPA Methods 25A and 503.
The 9000 H has a large graphical display and intuitive keypad to navigate the easy to use menu system which includes: on-board diagnostics, factory and local contact information, help menu, and a service reminder for preventative maintenance. These features make the 9000 H usable with minimal training.
For users that require external computing, all versions of the Series 9000 include a copy of the 9000 Keeper software. Using 9000 Keeper on a PC provides total control of the instrument, granting the user control of the method, alarms, relays, calibration, configuration, and data export and real-time viewing.
Reader Reply Card No 136 Reader Reply Card No 138
February/March 2010
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52
