Emerson Rosemount 8705 Magnetic Flowmeter Flanged Sensors

Product Description

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.

Specifications

Features

How it Works

FLOW MEASUREMENT

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.

INDUCED VOLTAGE

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.

FARADAY’S LAW

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.

COMMON USES

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.