Rosemount 8705 Flanged Magnetic Flow Meter Sensors provide long-lasting, reliable performance in even the most challenging applications. An all-welded construction provides a hermetic seal that protects against moisture and other contaminants. The sealed housing ensures maximum sensor reliability by protecting all internal components and wiring from even the most aggressive environments. A removable and replaceable terminal block enables easy repair in the field without the need to replace the entire meter.
Up to 0.15% of volumetric flow rate accuracy over 13:1 flow turndowns, 0.25% over 40:1 flow turndown
½-36 inch (15-900 mm)
PTFE, ETFE, PFA, Polyurethane, Neoprene, Linatex Natural Rubber
316L Stainless Steel, Nickel Alloy, Platinum, Tantalum, Titanium
ASME B16.5 Class 150-2500
DIN PN 10-40
AS BO122129 Table D and E
AWWA C207 Table 3 Class D (30-36 inch only)
IP68 (Recommended with sealed cable glands)
Compatible with all 8700 Series transmitters
Compatible with legacy transmitters: 8712D, 8712C, 8732C, 8742C
For maximum protection, a fully welded sensor housing provides a hermetic seal
Avoid process shutdown with a removable and replaceable terminal block that enables repairs in the field
Capture any potential process fluid leakage with optional secondary containment compartments to surround electrodes
Ensure reliability in the harshest environments with an all-welded sensor housing
Guard against installation damage and leading-edge wear with an optional lining protector
Minimize maintenance and repair with an obstructionless design featuring no moving parts
How it Works
Electromagnetic flow meters, or magmeters, are comprised of a transmitter and sensor that together measure flow. The magnetic flow meter’s sensor is placed inline and measures an induced voltage generated by the fluid as it flows through a pipe. The transmitter takes the voltage generated by the sensor, converts the voltage into a flow measurement and transmits that flow measurement to a control system.
A magmeter utilizes a set of coils and a pair of electrodes for flow measurement. The meter’s coils are driven by the transmitter with an applied current. Once powered, a magnetic field is formed between both coils. When the pipe is full and the fluid begins to flow, the force of the magnetic field causes the negatively and positively charged particles of the fluid to separate as they pass through the magnetic field. This separation causes an induced voltage between the electrodes and sensor.
The flow principle behind magnetic flow meters is known as Faraday’s Law, mathematically defined as E=k*B*D*V. The induced voltage (E) is directly proportional to the velocity (V) of the fluid moving through the magnetic field (B). The induced voltage is carried to the transmitter through the electrode circuit. The transmitter then converts this voltage into a quantifiable flow velocity. The volumetric flow rate of the fluid is calculated using this known velocity along with the area of the pipe.
Magnetic flow meters are well suited for a variety of applications across a range of industries including pulp and paper, metals and mining, water and wastewater, food and beverage, chemical and petrochemical and oil and gas. Because the magnetic flow meter design does not leave any protrusions or obstructions in the pipe, they are able to accommodate an array of applications from clean and sanitary liquids to slurries and highly corrosive or abrasive fluids.