Flow Finder Uses About Air Flow Restriction Flow Finder Engineering Symbols Identifying Bad Flow TDs Checking FTD Accuracy Choosing Flow Finder Ranges Flow Finders/Pipe Purification Flow Finders & High Valves Flow Finder vs. Portable Flow Rater Miscellaneous Topics Flow Gauge Conversions Using Flow Finders on Route that Does Not Have Flow Transducers Concerning Pressure Drop
In each Tip of the Week article we have tried to explain one or more applications for the Flow Finder and Flow Gauge. In this Tip we'll discuss a time-saving and convenient feature available for use with each of the various Flow Finder ranges.
Article #8: Flow Finders and High ValvesAugust 21, 2006
As discussed previously, determining air flow in Standard Cubic Feet per Hour (SCFH) with the Flow Finder equipment is achieved by first measuring the pressure differential created by the Flow Finder's internal calibrated orifice. This differential is measured by the Flow Gauge using the two tank valves installed on top of the Flow Finder. Because of the simple way in which the air pressure differential is measured, we have been able to develop a component which extends the remote manual measurement capability of the Flow Finder. This component, call a "high valve," is available for all original four Flow Finders as well as the high range 475 SCFH Flow Finder. And, as is the case with the normal reading of a Flow Finder, a remote manual reading does not cause any restriction in the air flow.
To simplify the reading process, Flow Finders and high valves are color-coded (as shown below) to correspond to the colored flow range scales on the Flow Gauge (see illustration in Tip #6, Choosing Flow Finder Ranges). If using a 0-475 SCFH Flow Finder, just use the blue scale for your flow measurements and multiply the measured value by ten.
A remote manual reading is accomplished by connecting two 3/8" plastic tubes from the Flow Finder to the high valve (as shown in the next illustration). The high valve is equipped with the proper spacing between the valve and the center screw assembly to allow for easy attachment to the "sampler" component of the Flow Gauge. In addition, the high valve includes a "polarization collar" which makes it impossible to seat the sample incorrectly. As a result, you will receive an accurate reading every time.
Because air pressure, and not air flow, is passed through the tubing, the distance between the Flow Finder and high valve is not limited. We've experimented with a working distance of 30 feet, but there is no reason why the distance cannot be greater.
The high valve can be used in several applications:
- In a manhole where a flow reading at at pipe tee is required, but entry is difficult. A wet or deep manhole is a good example of this situation. The high valve can be placed in the manhole collar for easy reading.
- As a "down valve" for aerial air pipe. The high valve could be placed on a pole at the midpoint of an aerial section and read from the ground.
- At a pedestal where conduct is run into a manhole. The high valve can be placed at the pedestal to obtain a reading.