44 of 124  Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 08: Electrical Works  Ambient temperature shall be between -40°C /+85 °C  Device housing and process connection shall be 316L.  The flow meters shall be based on ultrasonic transmitters on flumes or magnetic on pipes, if otherwise is not  necessary depending on process requirements. The transmitter shall include a pulse signal that gives a pulse for  a specific accumulated flow. The enclosure for all equipment shall be IP68. The technique shall be  microprocessor based. Flowmeters shall be selected considering cavitations and irregularities in fluid profile so that continuous  measurement will be assured. Process connections shall be flange type, if otherwise is not necessary depending  on process requirements.  Working principles and technical features of the equipment will be as follows:  8_Vol3_d4 3_Section 8 electrical works_en_GIR rev6.doc  • The calibration of the flow meter, will be possible by entering program values into the matrix inside the  equipment by using the adequate number of buttons on itself.  • Nominal diameter shall be suitable for pipeline diameter DN 25 to 2400 (1 to 90")  • The measuring principle is practically independent of pressure, density, temperature and viscosity  • The electromagnetic flow meter flow sensor must be mounted in a location, which is free from  interfering elements like valves, Ts, bends, pumps, etc. to ensure a laminar flow without turbulence  upstream of the flow sensor. For that reason the flow sensor must be mounted in a straight pipe at a  distance from interfering elements of minimum (5 x DN) upstream and minimum (2 x DN)  downstream. Valves should always be mounted on the downstream side of the flow sensor. If it  becomes necessary to use reducers, the inner angle must not exceed 7.5°.  • Failure rate, between 10-100% measurement zone, will not exceed 0.5% of the measured value.  Therefore, the device will keep its high sensitivity even in low flows.  • Microprocessor controlled sensitive electromagnetic flow meters that are designed to measure the flow  of liquid that has electrical conductance bigger than 5 micro/cm will be used.  8.8.16 Flow Measurement  • Protection type class is IP 65.  • Current output: 0/4...20mA, but by connecting LCD indicator, pressure will be readable at the field. • Supply voltage shall be 2-wire 220 VAC or 24 VDC loop powered.  • For high temperatures, types which are filled with oil resistant to special temperature will be usable.  • Its mount will be either aluminium or plastic (POM).  • Connection type shall be 1/2"gear, flanged optionally.  • For explosive and flammable environments, Ex-proof types will be used.  • Measurement range starts with 0...40 mbar. It will be able to change up to 0....60 bar.  • By the ceramic sensor it will be resistant and sensitive to the shock pressures that may occur in the  process and damage sensor, device’s standard sensitiveness will be 0.5%. If requested this value may be  decreased to 0.2%, their resistance against pressure shocks, will ensure them to be used easily in  pumping lines, for example a 0,4 bar device is going to be able to endure against 25 bar pressure. 