PECM Issue 38 2019 | Page 119

MASS FLOW ACCURACY FOR GASSES Some of the most important flavour contributors to beer are fermentation products such as esters, higher alcohols and sulphur compounds. The concentrations of these flavour compounds will be altered if the growth characteristics of the yeast are less than perfect. Achieving the optimum O2 level in the wort for each beer therefore is very important in terms of product quality, so an effective process to control the oxygen levels is essential. Using a mass flow sensor to establish the concentration of dissolved solids, and total volume, coupled with a mass flow controller to deliver the gas, is an efficient starting point. To improve the accuracy of the system even more, the signal from a dissolved oxygen (DO) probe in the fermenter vessel can provide feedback to adjust the setpoint and obtain the exact level of dissolved oxygen required. This offers the opportunity to maintain precise levels of dissolved oxygen which have a major impact on the quality of the final product. PH IN WATER Carbon dioxide (CO) is used to reduce the pH of the water for a number of reasons. Primarily, it is a gas that is easy to handle, non-corrosive and its most appealing feature is that it will not lower the pH of water below 7.0. In addition, the only maintenance required for the dosing system is to replenish the gas cylinders periodically. The control structure for this dosing system needs to cope with variable flow as well as decreasing gas pressure as the volume in the cylinders deceases. Using a mass flow controller that is calibrated for the gas and delivers accurate measurements independent of temperature and pressure, is very important. Oxygen levels can be accurately controlled during fermentation to ensure optimum product quality. The CIP process can involve a range of chemicals that are used to clean and disinfect the equipment. The concentration of these chemicals is very important in achieving an effective cleaning cycle without wasting expensive materials. Also, using control systems that are purely timer-based offers no confidence in the effectiveness of the process and also retains no meaningful data, which may be required for regulatory compliance. By examining the temperature and the conductivity of the cleaning fluid it is possible to determine if too much energy or too much chemical is being used. Any reductions in energy consumption or raw materials will have a beneficial effect on operational costs. Working with sensor manufacturers that have experience in this application to create a more sophisticated control and sensor feedback-loop system can therefore offer many benefits. Many will use a pH sensor after the dosing point and use this information to adjust the gas flow rate. This reactive process can be optimised by adding a pH sensor to the input side and using the readings from this sensor to set the CO2 dosing rate. The second sensor then acts as validation of the process setting. This offers a quicker response to changes in the pH levels at the input. Correctly positioned pH sensors for example can provide data on the effectiveness of the process, while conductivity sensors can provide a measure of contamination – once this figure has reached almost zero, the procedure can then be concluded with minimum delays to production. STREAMLINED PROCESSES Ultimately, improving data collection, interpretation and analysis can offer many advantages. Working with experienced process control manufacturers, such as Bürkert, can yield benefits across the board. From designing new installations to improving the efficiency and effectiveness of existing equipment, getting the right sensor in the right place will have a significant impact. Process optimisation is primarily about acquiring the correct data and using it as effectively as possible. This requires experience in the application as well as with the equipment itself to ensure a cost- effective and reliable installation. Bürkert has over 100,000 catalogue items, including cutting-edge flow measurement equipment that can also provide mass flow data. This expertise in manufacturing and expansive knowledge of numerous applications helps customers to reduce operating costs, improve productivity and ensure compliance with regulatory bodies where necessary. OPTIMISED CLEANING For those working in hygienic applications, clean-in-place (CIP) is a very important process that maintains the cleanliness of equipment. Using a combination of chemicals, water and heat, the process offers a very efficient method of cleaning vessels and pipework without dismantling them. However, time taken for cleaning is time lost from production, so this needs to be kept to a minimum whilst also ensuring that the process has been effective. Optimising the control of CIP reduces costs as well as minimising chemical usage and improving productivity. About BURKERT Burkert Fluid Control Systems is one of the leading manufacturers of control and measuring systems for fluids and gases. The products have a wide variety of applications and are used by breweries and laboratories as well as in medical engineering and space technology. The company employs over 2,500 people and has a comprehensive network of branches in 36 countries world-wide. Comprehensive process control installations can deliver considerable savings. www.burkert.co.uk Issue 38 PECM 119