Electricity + Control January 2018

round up PRESSURE + LEVEL MEASUREMENT + INSTRUMENTATION

Twice as easy: On the safe side with differential pressure measurement Florian Burgert, VEGA

P ressure vessels and process tanks have to meet high safety requirements. Continuous monitoring of the differential pres- sure plays a major role in minimising the risks from hazards such as excess pressure, leaks or dust-explosive substances. VEGABAR series 80 pressure transmitters have proven to be very effective for this task. And the method is simple: just put two of them together. Thanks to innovative technology, two of these pressure gaug- es can be quickly transformed into a perfect electronic differential pressure system. Two sensors of the VEGABAR series 80 deter- mine the process pressure with the help of two measured values: the tank pressure and the total pressure resulting from the pres- sure of the medium and the overpressure.The user can simply take a pressure transmitter from stock, order another identical sensor

with electronics version ‘slave’ and have an electronic differential pressure system up and running in a short period of time. As opposed to conventional differential pressure systems, elec- tronic differential pressure measurement with VEGABAR series 80 is not affected by the ambient temperature or strong vibration. When it come to maintenance this technology is also in a league of its own. As the two sensors are electronically wired together to form a single measurement, easy maintenance can be done on the de- vices individually, and it has another impressive feature: in the ver- sion with oil-free ceramic CERTEC measuring cell, the pressure transmitter is completely resistant to temperature shocks. In fact, this extremely high overload resistance factor of up to 200 can be found nowhere else on the market. Further CERTEC technology of- fers the major advantage of being installed flush with vessel walls, thus eliminating possible blockages to impulse lines no longer be- ing required which can cause blockages. Its simple operation based on the proven instrument platform plics and optional ‘second line of defence’ make it the ideal solution for differential pressure measurement.

Florian Burgert is in Product Management Pressure Instrumentation at VEGA. Enquiries: Chantal Groom Tel. +27 (0) 11 795 3249 Email. chantal.groom@vega.com

Organic load under control

CA80COD features a software-controlled safety cover that pre- vents opening of the digestion reactor when it is too hot or un- der pressure”, explains Endress+Hauser’s product manager Jan Swart. “It thus ensures the highest level of safety”. The precisely adjusted reactor temperature guarantees complete digestion of the sample and a redundant light barrier in the optical dosing unit provides the best level of reliability. • Precision starts with precise dosing Liquiline System CA80COD is equipped with peristaltic pumps that are able to cope with particles which is important for the de- tection of particle-bound COD. It also uses an optical dosing unit guaranteeing precise and reproducible dosing of small reagent volumes. Automatic cleaning and calibration functions make sure that the analyser maintains its precision over a long period of time without manual intervention. If disturbances should oc- cur, advanced diagnostics with remote access help plant manag- ers to analyse and remedy them quickly. Required maintenance measures can be carried out easily, reducing maintenance costs and increasing process uptime. Enquiries: Jan Swart. Email jan.swart@za.endress.com

Endress+Hauser ’s analyser for the chemical oxygen demand, Liquiline System CA80COD, is perfectly suited for environmental monitoring and applications in municipal and industrial wastewater. Reliable assessment of the organic load Chemical oxygen demand is the most commonly used parameter to determine the organic load of wastewater. Precise online measure- ment of COD in the inlet of wastewater treatment plants helps to re-direct heavily loaded water into buffer basins while measurement in the outlet enables plant managers to evaluate the cleaning capac- ity of their plants. In industrial wastewater treatment, COD is meas- ured in the outlet to support load-based billing according to the pol- luter-pays principle. Liquiline System CA80COD is the right analyser for all plant managers that require ‘true’ COD values to comply with regulations: It uses the established dichromate measuring method ensuring consistent comparability to lab measurements and its de- tailed logbooks provide all required documentation to the authorities. Safety for process and personnel • Since COD measurement requires thermal and chemical di- gestion of samples, operational and occupational safety play an important role in the measuring process. “Liquiline System

34 Electricity + Control

JANUARY 2018