Feature sponsored by Flow, level & control


FINDING THE RIGHT MASS FLOW CONTROLLER FOR VOLCANO RESEARCH


Successful research depends on high-quality, reliable data, which in turn, can only be generated by well-calibrated equipment. For research establishments, such as universities, repurposing equipment for new projects can be cost-effective, however, the equipment must still be able to meet the requirements of the new projects. For one post-doctorate researcher at Lancaster University, the latest investigation involves experimental work using equipment that needs to operate at relatively low air flow rates. The solution came from Bürkert, which supplied the original mass flow controller.


D 28


r Natalia Lipiejko has recently started a three-year research project at Lancaster University to


investigate granular flows with the aim of developing a model


that will help understand the rheology of pyroclastic density currents (PDCs). PDCs are mixtures of volcanic rocks and hot air that travel away from the volcano.


MEASURING MATERIAL BEHAVIOUR The investigation of granular flows, such as PDCs, often involves a rheometer, an instrument that is used to study viscoelastic


behaviour of various materials. High-quality rheometers represent a significant investment for researchers and if possible, the existing equipment should be used. For the project at Lancaster University, the equipment consists of a rheometer with a cell for the granular material. The cell is connected to a compressed air supply, which is used to fluidise the material. The flow rates of the compressed air are controlled by the Bürkert mass flow controller. Fluidisation means that the upward force exerted by the compressed air balances the weight of the granular material and the material behaves like a fluid. The experiments are performed using glass beads of diameters ranging from tens to


hundreds of microns. Glass beads have often been used as analogues for pyroclastic material. Additionally, results from experiments with glass beads are relatively easy to use to validate numerical models, which will be developed as a part of the project.


DETERMINING THE RIGHT FLOW RATE One of the first steps of the experimental procedure is determining the point (the air flow rate) at which the glass beads become fluidised. The minimum flow rate required to fluidise the glass beads strongly depends on their size. The flow rates provided by the original mass flow controller were too high for the smaller beads. However, reducing the air flow rate beyond the operational range of the mass flow controller would significantly reduce the precision of the measurements. Dr Natalia Lipiejko, explains: “We quickly realised that the mass flow controller in our rheometer needed to be changed. Replacing an accessory such as the mass flow controller would be a much more cost-effective solution than purchasing a new rheometer. Since we knew the manufacturer of the original mass flow controller, we contacted Bürkert directly to enquire about available options. “The communication with Bürkert was really good. We needed a drop-in replacement for the mass flow controller and it was important that the mechanical and electrical connections


The project at Lancaster University will provide new insights into the behaviour of volcanic rocks and hot air in PDCs as they travel.


June 2024 Instrumentation Monthly


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  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100