Global Flow Probe | Stream Flow Probes | Flow Monitoring

The Global Water Flow Probe is a highly accurate water velocity instrument for measuring flows in open channels and partially filled pipes. The water velocity probe consists of a protected water turbo prop positive displacement sensor coupled with an expandable probe handle ending in a digital readout display. The water flow meter incorporates true velocity averaging for the most accurate flow measurements. The Flow Probe is ideal for storm water runoff studies, sewer flow measurements, measuring flows in rivers and streams, and monitoring velocity in ditches and canals.

Turbo-Prop Sensor:

The Flow Probe incorporates the unique Turbo-Prop propeller sensor that uses the most accurate positive displacement technique for velocity sensing. The Turbo-Prop is designed to shed debris and is protected inside a 2" diameter housing. The probe housing may be placed directly on the bottom of pipes or streambeds for measuring low flows down to 2" in depth. The flow meter propeller rotates freely on its bearing shaft with no mechanical interconnections for minimal friction. Magnetic material in the propeller tip passes the pickup coil in the housing producing electrical impulses which are carried to the readout display by an internal cable. The Turbo-Prop, is easily removed for cleaning or replacement.

Digital Readout Display:

The Digital Readout Display receives an electrical signal from the propeller, amplifies the signal, and converts the reading to feet per second (or meters per second). The readout displays instantaneous velocity and true average velocity. The readout unit is water-resistant and incorporates a unique two-button operation for changing functions and zeroing the display. An internal watch type battery powers the unit continuously for one year and it is easily replaced. Also available on the readout is maximum velocity, time-of-day and stopwatch functions.

Probe Handle:

The Flow Probe handle is telescoping and is expandable from 3 feet to 6 feet in length (FP101) or 5 feet to 15 feet (FP201). It is constructed of anodized aluminum for light weight and long life. The Flow Probe may be easily extended up to 25 feet in length using standard PVC pipe and an electrical extension cable. This allows for sewer flow measurements from street level and measuring of stream flows from low bridges. A 3 ft. mylar coated staff gauge (graduated in hundredths of a foot and centimeters) is attached to the lower section of the water velocity probe for instant water depth measurements and accurate propeller positioning.

True Velocity Averaging:

The Flow Probe uses true velocity averaging. A running average is started once both buttons are simultaneously pressed, this zeroes the display, and when the water flow rate sensor is placed into flowing water. As long as the water velocity sensor remains in the flow, the averaging continues. Once the average reading becomes steady, the true average velocity has been obtained. When you pull one of Global Water's environmental flow meters from the water, the average value is frozen on the display until reset.

Flow Measurement:

Flow is determined by V (average velocity) x A (cross-sectional area)=Q (flow). The Area of a channel is known for pipes, or is determined for streams by measuring the distance from shore and depth at various points across the flow stream to construct the flow profile. The flow monitor offers two unique methods for determining the Average Velocity: 1) For small streams and pipes, the flow velocity probe is moved smoothly and uniformly throughout the flow profile. When you see a steady average reading, the true average velocity for the flow stream is obtained. 2) For larger streams, the water flow meters may be used to take a vertical profile of velocity at several points across the stream, which then become the average velocities for each of these subsections of the flow stream.