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African Petrochemicals July/ Aug Edition 15_4 {2018}

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WORLD FIRST SIL2 RATED SAFETY TEMPERATURE MEASUREMENT DEVICE FOR BOILERS The Safety-TL4896, a world first SIL2 rated temperature measuring device from Martens, which conforms to international boiler regulations offering a unique front panel installation is available from GHM Messtechnik South Africa. Certified to DIN EN14597 and DIN EN61508 the device gives an analogue actual value output for regulators and PLC eliminates the need for additional sensors. 22 Managing Director of GHM Messtechnik South Africa, Jan Grobler, said “The Safety- TL4896 is the first safety temperature measurement device in the world designed specifically for application in industries using boiler technology. I believe the device will generate enormous interest from plant operators from sectors such as paper and pulp, food and beverage, pharmaceutical, sugar, cleaning, hygiene and dairy”. “The device operates as a direct indicator, because it is installed in the control panel instead of on the top-hat rail, eliminating the need for an additional ‘indicator’” said Grobler, adding “an additional advantage is the execution of the reset function directly on the device, removing the need for an additional control element” he said. In boiler applications for hot water production, a safety temperature limiter must be provided in addition to the limit value monitor and minimum water level monitor in order to reliably suppress the energy supply in accordance with DIN EN 12828 – whether by means of deactivating the automatic firing device with ignition flame monitoring (gas operation) or a safety valve (oil supply) or a heating current interruption – as soon as any of the limiters reacts. With self-sufficient device technology as required by DIN EN 61508 “Functional Safety”, i.e. independent of PLC systems, regulating systems and SCADA systems, only the permissible safety temperature limiters are used for industrial heat generators in accordance with DIN EN 14597 and the safety requirement level of functional safety in accordance with SIL2. Combined heat and power plants require safety temperature limiters for self-sufficient monitors for the hot water, the over temperature of motor preheating, motor cooling water, exhaust gas and calorific value heat exchangers. In hot steam production, additional safety elements must be used in order to monitor boiler systems equipped with over heaters. Our solution The Safety-TL4896 safety temperature limiter has a safety shut-off contact and an adjustable pre-contact in order to warn of impermissibly high actual values independently of the regulating and control device. Before the forced shut-off is activated, additional alarm messages can be issued and corresponding functional processes can be initiated in order to achieve a safe stand-by status, eliminate errors and avoid timeconsuming and costly complete shut-downs and the subsequent restart of a plant. The high-quality analogue output of the actual process value offered with the Safety-TL4896 enables further processing in the automation system and eliminates the need to install an additional sensor. Benefits Electronic safety temperature limiters were previously often built, for example, as tophat rail devices in switch cabinets. Now, for the first time, the device offers installation in the front panel. In the process, the actual and limit values on the large display can be read conveniently and the reset process after correction of the cause of an error takes place on the front panel in the same manner as for all other operating processes. As a result, separate devices and their wiring can be eliminated, because their functions are already integrated: indicator and reset button. With the adjustable pre-alarm, no additional limiters are needed and a redundancy to the automation unit is provided. A second additional measuring chain is eliminated by the analogue output. The Safety-TL4896 can be configured with the front buttons and tailored to the application. Summary Particularly with small and compact systems whose complete automation electronics are contained in the operating device (e.g. with use of the GHM-ONE multi-function device or a compact industrial PC/PLC system), there is no longer a large, conventional traditional switch cabinet. As a self-sufficient front panel unit in slim DIN format 48x96, the new Safety-TL4896 enables a consistently compact design of modern small systems, reduces the wiring work and facilitates ergonomic operation in the monitoring and observance of safety requirements. The Safety-TL4896 offers time and cost advantages in wiring and installation. With the easy operation from the front side, the requisite safety functions and ergonomic operation of safety temperature limiters is fulfilled for the first time. Further information is available from: Jan Grobler, Managing Director, GHM Messtechnik South Africa Tel: 011 902 0158 Email:

ROBUST DIFFERENTIAL PRESSURE FLOW METER/ MONITOR FOR LIQUID AND GAS Instrotech is offering the Kobold RCD flow meter, for measuring and monitoring the flow of liquids and gases. Depending on the model, the measuring range of the device is from 0.5 to 2350 l/min for water and 0.5 to 2750 Nm3/h for air with connections G1/2 to G3, ½ “NPT to 3” NPT. It can also be used to measure and/or monitor other liquids and gases. The functional principle behind this meter is the Venturi tube, developed by Italian physicist Giovanni Battista Venturi (1746-1822). This device consists of a tube that first narrows and then expands; the pressure difference between the inlet of the narrowed area and the narrowest area allows the flow to be determined. Within the housing, passages register the resulting differential pressure and transmit it to a bellows system in the display housing. The bellows system is protected by stop pins whenever the maximum rated flow is exceeded. With mechanical displays, the flow value measured by the bellows system is transferred to the calibrated display (in l/min for water and N/m3/h for air), and indicated by means of a pointer element. With electronic displays, a Hall sensor converts the mechanical movement into an electrical signal. The strength of this signal varies with the flow. Various electronic systems are available to display or monitor and evaluate the flow volume. Specific display scales are available for use with any media at any pressure and temperature. This flow meter is appropriate for use in the areas of: machinery, plants, chemical and pharmaceutical industry, heavy industry as well as the beverage and luxury-food industries. Special advantages of the unit are: no moving parts, universal mounting, self-monitoring, and easy operation. Measurement accuracies are 3% of the upper range value, with a reproducibility of 1%, also of the upper range value. The maximum service temperature is 100°C for a needle indicator and 80°C for an electronic display. For more information on: Kobold’s RCD Differential Pressure Flow Meter/Monitor, contact Instrotech Tel: 010 595 1831 Email: Air Products South Africa (Pty) Limited manufactures, supplies and distributes a diverse portfolio of atmospheric gases, specialty gases, equipment and services to the Southern African region. Air Products touches the lives of consumers in positive ways every day, and serves customers across a wide range of industries from food and beverage, mining and petrochemicals, primary metal and steel manufacturers, welding and cutting applications to laboratory applications. Founded in 1969, Air Products South Africa has built a reputation for its innovative culture, operational excellence and commitment to safety, quality and the environment. In addition the company aims to continue its growth and market position in the Southern African region. Service that delivers the Difference 23


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