Detects and confirms liquid flow
Uses the cooling effect of a flowing fluid or gas to monitor the flow rate. The amount of thermal energy that is removed from the tip determines the local flow rate. The sensor tip of the flow sensor houses two transistors and a heater element. One transistor is located in the sensor tip, closest to the flowing fluid. This transistor is used to detect changes in the flow velocity of the liquid. The second transistor is bonded to the cylindrical wall and is a reference for ambient fluid conditions. When power is applied, the tip of the probe is heated. As the fluid starts to flow, heat will be carried away from the sensor tip. Cooling of the first transistor is a function of how fast heat is conducted away by the flowing liquid. The difference in temperature between the two transistors provides a measurement of fluid velocity past the sensor probe. When fluid velocity is high, the temperature differential is small. As fluid velocity decreases, there is an increase in temperature differential.
As liquid flow increases to the actuation setting, a magnet-equipped shuttle is displaced. When displaced by fluid flow, this shuttle actuates a reed switch within the unit stem. A compression spring provides shuttle return when flow decreases.
A piston, encapsulating a permanent magnet, is positioned in the flow path within the unit housing. When displaced by the pressure differential from fluid flow, this piston magnetically actuates a reed switch within the unit.
Liquid flow in either direction deflects the paddle which, by cam action, displaces a permanent magnet equipped shuttle along the unit stem. The magnet actuates a reed switch within the stem.
The liquid flowing into the meter is split into individual jets by a guiding blade. These jets hit the rotor evenly from different directions, setting the rotor in motion. The rotation speed of the rotor is then converted into an electrical pulsed signal (frequency). The rotors are fitted with magnets and a Hall Effect sensor detects the rotation of the rotor. The speed of rotation is directly proportional to the flow rate.
Consist of a chamber that obstructs the media flow and a rotating mechanism that allows the passage of fixed-volume amounts. The amount of liquid or gas that passes through the chamber determines the media volume. The rate of revolution determines the flow rate.
Measure the time it takes for an ultrasonic signal transmitted from one transducer to cross a pipe and be received by a second transducer. Upstream and downstream time measurements are compared. With no flow, the transit time would be equal in both directions. With flow, sound will travel faster in the direction of flow and slower against the flow.
Designed for measuring electrically conductive liquids using Faraday’s inductive measuring principle. Electrons in the fluid are driven to the pipe wall when passing through the magnetic field created in the measuring pipe. This causes a potential difference that is detected by two laterally mounted electrodes. Based on the known magnetic field and the electrode spacing, the measured potential difference at the electrodes is proportional to the flow speed and therefore the flow rate.
Operates using the calorimetric flow principle, which detects the transfer of heat in thermally conductive fluids. The temperature detecting elements are platinum RTDs. One of the elements (R1) detects the temperature of the fluid in the pipe and the resistor (R2) is connected to a heater. The heating element heats R2 to a temperature that is slightly above the temperature of the surrounding fluid. When there is no fluid flow, the difference between R1 and R2 remains constant. As the fluid moves through the sensor, heat is conducted away from the heated element causing the temperature of R2 to decrease. This heat loss causes the differential resistance input to the amplifier where the various outputs of flow and temperature are generated.