Flow Meters

The convenience of ultrasound sensors lies in their ease of deployment and that they do not require the plumbing to be opened for installation. They are however, one of the more expensive sensors to measure flow and/or velocity. Ultrasound flow sensors have difficulty detecting, low flow and typically cannot detect flow below 0.05 gallons per minute. Therefore, we do not recommend them for leak detection and especially not for small leaks. Ultrasound flow sensors are a great choice for short to medium studies to measure flow patterns or thermal energy consumption, when opening the plumbing system is either not desired or difficult to achieve. Ultrasound flowmeters are available both for water and other liquid flow as well as gases such as natural gas. Output is typically a 4-20 mA, a voltage signal, Modbus or serial communication.

Pulse flow meters come in a variety of packages, but they're all in line, meaning the plumbing system must be opened to be installed. For water heater measurements this may not be a big issue as many water heaters are connected via a flexible connector that makes it easy to install small pulse flow meters. Also, it easy to attach a pulse sensor that reads the pulses from existing revenue water flow meters installed at the property line by water utilities. Pulse flow meters, have considerable accuracy, and are among the most inexpensive flow measurement methods. They are an excellent choice for long term studies or when the budget won't allow for more expensive clamp on type flow meters. The pulses are counted and correlated to flow using a K-factor, a formula that calculates the flow from the pulses over time, inner diameter of the pipe and the geometry of the turbine or flow wheel used in the sensor.

Vortex flow meters are less expensive than ultrasound flow meters. Like pulse flow meters they must be plumbed in and therefore are not always an ideal choice. Vortex flow meters cannot read flows below 1L per minute or 1/4 gallon per minute. This makes them ill-suited for leak detection. Their big advantage is that they also measure the pressure and temperature simultaneously, making them convenient and easy to implement. Output is typically a 4-20 mA, voltage signal, Modbus or serial communication.

Magnetic flow meters have no moving parts inside the pipe and are therefore ideal for liquids or water that contain a lot of contaminants or solids. They are all in line, meaning the plumbing system must be opened to be installed. Magnetic flow meters are in the medium price range depending on the accuracy required but should always be considered if their characteristics fit the application. Output is typically a 4-20 mA, a voltage signal, Modbus or serial communication.