The production and processing of food and beverages are subject to strict laws, regulations, and industry codes of conduct. The purpose of these rules and guidelines is to minimize the risk of harm to consumers from products containing potential foreign objects or bacteria. The use of pressure gauges is an important component of safe food production.
Pressure and liquid level measurements in the food, dairy, beverage, and manufacturing industries need to be conducted in pipelines, filters, and storage tanks. Pressure instruments must be accurate, not affected by vibration, able to withstand the temperature and stress generated during the cleaning process, and have dedicated liquid receiving components. Specific applications include balance tanks, silos, storage tanks, mixing processes, seasoning systems, pasteurization, emulsification, filling machines, and homogenization, among others.
Most electronic pressure transmitters use elastic diaphragms as pressure transmission components. By using appropriate process connections, the pressure transmitter can be installed without any gaps and is easy to clean. CIP cleaning system (Clean In Place, also known as in-situ cleaning) is used to clean the inner surfaces of pipelines and storage tanks in liquid and semi liquid food and beverage processing equipment. Usually only large water tanks, kettles, or piping systems with smooth surfaces can be cleaned in this way. The "liquid receiving part" of the pressure transmitter is the diaphragm, which is in contact with the measured medium and must be able to withstand the forces and temperatures generated during CIP cleaning and sterilization processes. Regular cleaning and seamless design can reduce the risk of contamination, but the surface of the liquid receiving components must also have a smooth contour, without sharp corners or gaps, to avoid medium accumulation and decay. Usually, this component is made of stainless steel to prevent medium adhesion.
The Graeff clamp type sanitary pressure transmitter is designed to meet the requirements of most food and beverage industry applications. This series of pressure transmitters is sturdy and durable, made of stainless steel, and can provide excellent stability and accuracy over a long service life. The flush diaphragm is suitable for CIP and can be directly installed in the process. Other pressure interfaces can be selected according to different requirements.
One method used for continuous measurement of liquid level in the food and beverage industry is the hydrostatic pressure method. Static liquids cannot withstand shear deformation or tensile force. The main force between adjacent parts in still water and the static water on the edge wall is pressure, which is called static water pressure. The liquid column above the pressure sensor generates hydrostatic pressure, which is a direct indicator of the liquid level. The measured value depends on the density of the liquid, which can be used as a calibration parameter input.
Graeff input type liquid level transmitter is designed for liquid level measurement in various application scenarios. The liquid receiving part is usually made of 316L stainless steel, making it suitable for immersion in most media. The product has no leakage during long-term operation and high stability. The front-end anti sand cap serves to protect the sensor diaphragm and can be configured with wear-resistant, oil resistant, acid alkali resistant, high-strength specialized breathable cables according to different usage sites, ensuring that signal transmission is not affected by external liquid pressure changes.
In the case of an open container, atmospheric pressure acts on the top of the liquid, and a gauge pressure sensor can be used. For sealed containers, two separate gauge pressure transmitters or a single differential pressure transmitter can be used for measurement. Control systems in the food industry typically use differential pressure transmitters for liquid measurement due to their robustness and simplicity. Graeff's differential pressure transmitter adopts high-precision silicon sensor technology, which can achieve platinum level accuracy of ± 0.05% and can be used for static pressure up to 32MPa, providing precise measurement guarantee for the food and beverage industry.