Midwest Instrument is a small manufacturing company specializing in paddle wheel water flow meters utilized in irrigation, aquaculture and other applications where a simple water flow meter is required. These flow meters all utilize a paddle wheel design that measures flow in pipes ranging in size from 1/2" up to 8". The meters are offered in three different versions. All three of these versions utilize the same paddle wheel system.
The first version, which was also the original and most popular version, has the LCD display mounted to the sensor which is attached directly to the pipe. In many applications this is acceptable and works satisfactorily. This is also the lesser expensive of the meters with the digital display.
These are the PT series
The second version has the paddle wheel sensor and display separated by up to 15'. Many times pipes are suspend or below the surface and not easily accessible. This version allows the display to be mounted in a location that is easily viewed while the sensor is not accessible for viewing.
These are the RD series.
The third version is simply the paddle wheel sensor with no display. The sensor has a 2 conductor wire for interfacing with a data acquisition system. This sensor is a mechanical switch that opens and closes once per revolution of the paddle. This series of pulses is timed and scaled in order to calculate flow rate. The user is responsible for choosing and implementing the data acquisition system.
These are the PO series of meters.