Dear all, Good morning.I would like to know which material we can go for orifice plate in sea-water service i.e) Monel or Hastelloy-C .Which is better cost-wise(less expensive). Thanks in advance for those we will be answering this query. Regards, GB

Thanks for your immediate response.Could you please give a suitable range of velocities & pollutants in sea water for which monel , hastelloy-c to be selected ie)general guidelines(rule of thumb) choosing between monel & hastelloy-c? In one of the offshore project, for control valve in sea water service we have gone for Al-bronze body & Monel trim(plug,seat,stem etc).But we had a doubt on choosing the material for slightly thinner items like Orifice plate,Diaphragm & were looking for good guidelines/rule of thumbs from experts like you. Regards, GB

gb-sv, This response sort of evades the question...... but, here goes anyway I am assuming that the orifice plate that you are refering to is part of a flow measurement device. If so, why don't you try a different technology for flow measurement ? My opinion is that a "clamp-on" ultrasonic device may be more suitable. There can be soilds but no appreciable gas contenet in the flow.You would (1)save the cost of a set of flanges, (2) can move the device within the system if necessary, (3) not have to worry about a loss fo accuracy because of plate degradation or fouling and (3) might save money on the total installed cost.... Several companies make these devices ( www.controlotron.com comes to mind) Use GOOGLE and search for ultrasonic flow measurement. Check to ensure the accuracy of the device is acceptable My thoughts only MJC