Flow, level & control

to fermentation temperature, oxygen is used to start the fermentation process. If air, which contains 20 per cent oxygen, is

added, then the process can only achieve an O2 concentration of eight parts per million (ppm).

For higher levels, around 10 ppm, typically used by commercial breweries for higher strength beers, pure oxygen is required. However, the ability of the wort to absorb

oxygen is affected by its specific gravity, which is measured on the Plato gravity scale. This measures the concentration of dissolved solids in the wort. Furthermore, each yeast strain has an optimum oxygen level and if this is not achieved precisely, the optimum fermentation rate will not be achieved.

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 (CO2) 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. 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.

Instrumentation Monthly April 2019

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. 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

Automated analysis saves time for many industries

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. 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

Comprehensive process control installations can deliver considerable savings

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.

Bürkert 35

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  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80