In industrial processes where liquids, air or gases are used, process sensors serve to measure and detect pressure, temperature, flow and levels.
Pressure sensors are used to detect the system pressure of oil in hydraulic systems or to measure the hydrostatic pressure in tanks and vessels in the food and beverage industry.
Flow sensors monitor the coolant and lubricant supply of machines, power units and industrial furnaces or ensure ventilation of installations and buildings. Electronic level sensors monitor filling levels of liquids or bulk materials in containers, tanks and silos.
In the food, beverage and pharmaceutical industries, temperature sensors are used to ensure that products are at the correct temperature. In machine tool and automotive applications, the temperature or temperature difference measured at drives, gears and motors plays an important role as an indicator of the machine condition. In the metal and glass industries, temperature monitoring of cooling circuits serves to prevent overheating of plants.
Valves are used for dosing and control of liquids, air or gases. Dual inductive sensors provide reliable position feedback for pneumatic valve actuators and valves. Valve sensors provide position feedback on linear valves.
Flow sensors and flowmeters
In almost all fields of process and plant engineering, liquids or gases are used, e.g. for coolant and lubricant supply of plants and power units or ventilation of installations and buildings. Electronic flow sensors are used to prevent damage or downtime caused by flow interruptions. ifm’s product range comprises flow sensors with different measuring principles for monitoring the most varied types of media, including water, oils and coolants, but also air, compressed air or aggressive media. Their application areas range from simple monitoring tasks to precise flow rate measurements.
Precise monitoring of processes
Thanks to its optimised measuring pipe, the new magnetic-inductive flowmeter of the SM series now covers measuring ranges of up to 150 l/min. Besides the flow, the temperature and the total quantity are measured.
Despite the compact dimensions, the high temperature resistance of up 90°C allows operation in difficult applications such as ovens, where the cooling water reaches very high temperatures. The TFT display shows several process values simultaneously, and the two separate switch point LEDs and the optional colour change provide an ideal overview. In combination with the intuitive operation via three buttons, the self-explanatory menu items considerably reduce the setup time of the sensor.
Advantages and customer benefits
Process reliability and energy monitoring: the overheating of tools, welding guns or ovens leads to increased wear and eventually to production downtime. Continuous monitoring of the water cooling ensures the process reliability of applications requiring intensive cooling. For this, the SM type flowmeter features high accuracy and integrated temperature measurement. In combination with the total quantity meter (totaliser function) it is also possible to implement reliable energy monitoring.
Pump output can be reduced thanks to the minimisation of pressure loss: the optimised design of the measuring pipe with an increased internal diameter reduces pressure drops. Advantage: pump outputs can be reduced. This saves energy costs.
Reduction of setup and hardware costs thanks to IO-Link: several measuring parameters (flow, temperature, total quantity) can be evaluated in the controller via only one input. Measuring points, wiring and PLC input cards are reduced, which saves costs. The integrated simulation function simplifies the setup. The sensors can be integrated into the controller and be checked without the plant being in operation.
Slim design optimised for standard splitter boxes: to separately monitor individual cooling lines, several flowmeters are used simultaneously. Their slim design featuring an ideal installation position and a connector position optimised for practical use renders complex piping and the displacement of sensors unnecessary. This allows use in standard water distributors with an internal diameter of 50 mm. Another characteristic: no inlet and outlet pipe lengths upstream and downstream of the sensor are required. This enables maximum flexibility for the layout and installation of the plant.
Application examples
Injection moulding machine: the cooling water quantity and the temperature are key factors when it comes to the quality of the final product. Clogging must be detected without delay. This is ensured by the SM flow sensor.
Hardening system: the cooling curves of workpieces must be adhered to during hardening processes. This is done by applying a defined quantity of cooling water to the previously heated workpiece. The SM detects potential clogging, ensuring a continuously high product quality.
Machine tools: permanent cooling water supply ensures consistent quality and extends the lifetime of the tool. Swarf can clog cooling water pipes. The SM detects this in time and prevents overheating of the tools.
Oven construction: lack of cooling water can lead to dangerous excessive temperatures in the oven. The SM monitors the cooling water quantity and temperature up to 90°C. Expensive downtime due to excess temperature is a thing of the past.
SM flowmeters solve a tricky control problem in a chilled water system
Swiss-based HeiVi is a specialist in the planning and project management of heating and air conditioning systems. As co-founder Peter Heimann explains: “Our target is to obtain maximum energy and economic efficiency with comfort and ease for our customers. To achieve this, we often have to think outside the box.”
This was recently the case when efficiency difficulties were experienced with the water chilling system at a branch of the Schweizerische Nationalbank in Basel. The problem was identified as a shortcoming in the control of the chiller’s compressor and associated storage water reservoir charging pump.
Out-of-the-box-thinking results in substantial energy savings
To optimise the process, a method of controlling the storage charging pump and the compressor in line with the demand for chilled water from the storage reservoir was needed.
Using ifm’s volumetric flowmeters of type SM6500, HeiVi devised a method to balance the storage tank’s charging and discharging mass flows according to a formula that would ensure optimal efficiency under all conditions. With the ‘zero volumetric flow’ control achieved by means of the ifm flowmeters, performance control of the compressor could be fully utilised, which resulted in substantially reduced overall energy consumption. Consequently, the chiller could be made smaller, which brought about an additional saving on the initial investment. The bonus is the ongoing cost saving that accrues through the reduced energy demands of the system’s storage water charging pump.
A well satisfied Heimann concludes: “We have subsequently equipped several branches of the Basel Kantonalbank with the new process, as well as the Cler Bank in St. Gallen and the laboratory of the Baugewerbliche Berufsschule in Zurich. All thanks to ifm’s flow sensors of the SM range.”
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