Sea water is a kind of fluid with stronger corrosives. At the same time, waves and tides produce low frequency reciprocal stresses and impacts on metal parts. And marine microorganisms, attachment organisms and their metabolites also produce direct or indirect acceleration for process of corrosion. Ocean corrosion is mainly localized corrosion, which starts from the surface of the component and occurs in a very small area, such as galvanic corrosion, pitting corrosion and crevice corrosion. Thus, when select sea water flow meter sensors, it is very necessary to consider the corrosive problems.
Sea water flow meter sensors mainly have inline magnetic flow meters and clamp on ultrasonic flow meters. The following are main introduction how to select magnetic flow meter and clamp on flow meter for different sea water.
If the sea water has lower concentration and small salt particles, transit-time clamp on ultrasonic flow meters are better choices. Such flow meters don't need to contact sea water and avoid corrosivity. Meanwhile, its flow transducers are not metal parts and not afraid of corrosive material. For such sea water, if select magnetic flow meter, 316L stainless steel electrode and rubber lining material should work well.
Warm tip: We have developed clamp on ultrasonic flow sensor for such application, because common model may not ensure good performance all the time. If you have such requirement, please feel free to contact us for more information.
If sea water has bigger concentration and bigger salt particles, doppler clamp on flow meter is a better solution. If want to select inline magnetic flow meter for better performance, it is better to select Hastelloy C electrode and PTFE lining material. Hastelloy C electrode is suitable for oxidizing salts such as Fe++,Cu++ and seawater.
Flow Sensor Meters for Sea Water Desalination
Water resource is becoming more and more expensive, and many countries and areas are facing serious challenging of water lacking, especially lacking of fresh water. At present, a large-scale sea water desalination factory can produce hundreds of tons of fresh water each day. The main advantage of desalination project is plenty of sea water resource, and its technology is not influenced by air and weather. Thus, it is believed that the cost of such desalinated water will be lower than current tapping water in near future. This will provide enough water guarantee for life and industrial manufacturing in sea side areas. Sea water desalination are drawing more and more attention in the world.
Talking sea water desalination project, it is necessary to use water flow meter for sea water inlet rate and fresh water production rate. For the projects, there are two main of digital water flow meters: inline magnetic flow meters and clamp on ultrasonic flow meters. The advantages of magnetic flow meters are accurate, stable, etc, but the disadvantage is too heavy, higher price, narrow flow range, higher velocity startup, corrosive metal body, etc. Comparing with magnetic flow, clamp on flow meters have advantages: higher accuracy, wide flow range, low velocity startup, very light, clamp on flow transducer are not afraid of corrosives, low cost, etc.
Sea water desalination projects mainly use plastic pipe as water transportation. Many pipeline are held in the sky. If use inline magnetic flow meters, the magnetic flow has bigger weight and plastic pipe can't hold it well. As a result, supporting brackets have to be installed, and this will improve much cost and cause much inconvenience.
That's why we recommend transit-time ultrasonic flow meters. Firstly, clamp on ultrasonic flow meters have many advantages, e.g. no pipe cutting, light weight, easy to install, no maintenance, etc. Clamp on flow meters also have fixed and portable type optional. And clamp on ultrasonic flow meters are much cheaper than inline magnetic flow meters, especially for pipe size over 40mm. Thus, if for sea water desalination, clamp on flow meters should be the ideal solution.