Intelligent electromagnetic flowmeter in the application of chilled water

Intelligent electromagnetic flowmeter is widely used in the current industrial production, and can be applied to a variety of conductive liquid measurement, especially water-based fluids and a variety of acid and alkali fluids. Today, the engineers and technicians of Qingtian Instruments will briefly introduce the advantages of electromagnetic flowmeter in chilled water measurement, as well as some issues that should be noted in the selection and installation. Intelligent electromagnetic flowmeter in the cold water flow measurement has obvious advantages, which can also be reflected in the cold water flow measurement. Corrosion resistance is especially important for salt water chilled water.

In high-rise buildings, some of the air-conditioning water pressure is high, can be negotiated with the instrumentation manufacturer, specifically manufactured to meet the requirements of the pressure resistance of the intelligent electromagnetic flowmeter. The following issues need to be considered in the specific design approach.

• 1. If the chilled water is fresh water, choose a rubber lining, which is less expensive. If the chilled water is salt water, a PTFE lining must be selected. If fresh chilled water and salt water are to be tested, a PTFE lining must be selected.
• 2. The lining is subject to negative pressure When the cold water flow is measured normally, the measuring pipe itself is not subject to negative pressure. Negative pressure only occurs in the upper part of the pipe when the water stored in the pipe is discharged, because the venting valve at the high point of the pipe forgets to open.
• 3. Moisture protection of the excitation coil of the measuring tube of the smart electromagnetic flowmeter There are two commonly used methods to seal the excitation coil in the smart electromagnetic flowmeter inside the housing.

One method is to use the top and bottom half shells and screw the seals down for sealing. Another is to seal the coil from the outside by welding the housing. Of these, the latter is more reliable and completely eliminates breathing in the coil cavity and prevents the intrusion of outside moisture. However, the cavity around the coil is always filled with air during the manufacturing process and the water vapour content in the cavity varies with atmospheric temperature and relative humidity during assembly. If the water vapour content is high, after the flowmeter is put into service, condensation may occur due to the drop in temperature in the conduit and cavity, leading to moisture in the coil and insulation damage.

Thus, when the temperature of the chilled water is low (some manufacturers limit it to 0), nitrogen is used instead of air in the cavity, and when the temperature is low (e.g. -10 or lower), methyl silicone oil (some manufacturers use transformer oil) is used to fill it. Different manufacturers have different practices, but the general principle is that the enclosed drying medium does not leak and the insulation of the coil does not degrade during long-term use. The development of the instrument industry and technological breakthroughs in the instrument industry cannot be achieved without the support and efforts of various instrument manufacturers.

As a flowmeter manufacturer, Supmea endeavours to learn new technologies from others, introduce advanced equipments, and develop more technologies to meet the needs of more customers.The series of flowmeters produced by Supmea are also gradually sold all over the country, and are well received by customers.