Is the pressure in the tank correct? Compact, hygienic system solution for pressure control
Regardless of whether carbonated water, beer or vaccines are being produced, the pressure blanketing in tanks and storage containers always requires precise monitoring since process reliability suffers significantly if the gas pressure in the free part of the container is incorrect. Errors can reduce the quality of the often valuable products, lead to rejects and thus cause high costs. Compact, hygienic system solutions for pressure control are, therefore, the means of choice for increasing process reliability, e.g. in fermentation processes, when filling sensitive media in a protective gas atmosphere or when storing water for injection solutions (WFI).
The systems for controlling pressure in tanks in the pharmaceutical, food and beverage industries usually consist of a combination of sensors, valves, pressure controllers and controllers; they are, therefore, usually made up of many components. Users generally purchase the components from various manufacturers and then combine their solution on site. This works, of course, but also involves a whole host of disadvantages that often only become apparent during actual operation. Thus, smooth interaction of the individual components is not necessarily guaranteed. This may actually result in longer signal processing times. In addition, the space required for the individual components is often quite extensive, compressed air losses are usually unavoidable and cleanability and sterilisation can cause problems.
Compact system from a single source
In the meantime, there is a practical alternative: Bürkert Fluid Control Systems has developed a compact, hygienic system solution for controlling the pressure in tanks that responds very quickly to changes in temperature and filling quantity as well as to chemical reactions. The tank blanketing system increases process reliability and sensitive media can be protected or product quantities can be dosed precisely. The compact solution requires little installation space, the components are perfectly matched, the system can be validated, is easy to retrofit and, last but not least, strikes a chord with users due its excellent price/performance ratio.
The pressure blanketing system consists of two bellows valves with an integrated process controller, an internal air duct and a pressure transmitter. The PTFE bellows ensures clean media separation, while being FDA certified and sterilisable. The shared stainless steel base body of the system can be emptied completely in a vertical position and its low dead space design guarantees easy cleaning. In fact, cleanability has been confirmed through a VDMA riboflavin test. Different industry-standard connections ensure easy integration or simple retrofitting in the respective process.
Automatic pressure control
The possible applications of automatic pressure control are wide ranging and extend from fermentation processes and the filling of sensitive media in a protective gas atmosphere to the storage and delivery of water for injection solutions. The basic mode of operation is always the same:
If a medium is filled into a tank, the available volume for the protective gas, e.g. nitrogen, decreases. In order to keep pressure blanketing constant, i.e. to compensate for the rising pressure due to the increase in the medium level inside the tank, a signal exchange takes place between the proportional valves and the pressure sensor installed in them, and the relief port is opened to achieve the preset blanketing pressure. The second valve remains closed during this function. If the medium is then removed from the container, e.g. at tapping points for WFI, the available volume for the protective gas increases. In order to then keep the preset pressure constant and to compensate for the drop in pressure due to the reduced medium level, the second proportional valve for the gas feed now opens according to the pressure sensor signal. The first valve remains closed during this function. The gas pressure is, therefore, controlled precisely and reliably and constant pressure blanketing takes place.
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