FIELD PROCEDURE:

Calibration of the rotor/prop units:

Equipment needed:

· “Maintenance & Calibration” binder

· All current meters and wands

· All rotor/prop units, including spares & replacements

· Measuring tape

· Tape to mark starting and end points

· Stopwatch

· Clipboard, paper, pencil

· 1/16” Allen wrench

· Replacement parts for rotor/prop assemblies

· (Alcohol)

MAINTENANCE & CALIBRATION NOTEBOOK:

Record all calibration and maintenance activity in the “Streamkeepers Maintenance & Calibration” binder kept in the Streamkeepers office. See the binder for details.

WHEN TO CALIBRATE:

1) Each Swoffer meter should have two rotor/prop units to accompany it into the field: a primary and a spare. All of these rotor/prop units should preferably be calibrated at the same time.

2) New rotor/prop units should be calibrated before going out in the field, but if that is not possible, they should be assigned a calibration number of 184 (per Bob Swoffer, company president, phone conversations with Ed Chadd and Jeff Bohman, August 2000 and August 2002).

3) Rotor/prop units should be recalibrated when any of the below are true:

a) A unit is first put into service.

b) Some kind of blow deforms a prop in a minor way—a slight chip or bending.

c) A unit fails the blow-spin test (see below). In this case, unscrew the thrust bearing nut and clean the inside of the nut, the rotor shaft, and the bore of the rotor unit with water or alcohol—but do not lube. If the unit then passes the test, it should be recalibrated. (If the shaft shows visible signs of wear, replace it.)

d) Two monitoring seasons have elapsed since the last calibration.

CALIBRATION PROCEDURE:

1) Each rotor/prop unit should have a unique number written on it, and should be assigned to a particular wand and meter. Track these assignments in the calibration notebook.

2) Before calibrating each rotor/prop unit, perform the following two tests:

a) Before attaching the rotor to the boom, perform a hand-spin test: Hold the rotor unit vertically by the steel rotor shaft with the prop facing up, and give a super-fast spin to the nut on top of the prop by “snapping” your fingers. The rotor fails the test if you hear a buzz.

b) After hooking up the entire unit, perform a blow-spin test: Turn the meter to “Count,” then hold the wand so that the prop is facing up, and blow very hard straight down on the prop. Right after you stop blowing, hit the “RESET” button on the meter and allow the rotor to coast to a stop. If the count is consistently less than 300, the rotor fails the test.

If the rotor unit fails either of these tests, it needs to be either repaired or replaced prior to calibration—see the “Troubleshooting” section below.

3) Follow calibration instructions at the Swoffer web site, www.swoffer.com. Use a calm wading pool, swimming pool, or other still water with a minimum run of 10’ (20’ is better) and depth of 6” to conduct the test. With each unit, conduct eight trials: 4 at about 2 ft/sec and 4 at about 0.5 ft/sec walking speed. (These speeds were chosen because the Swoffer meter performs fairly consistently at velocities >1.5 ft/sec and undercounts by successively greater amounts at velocities <1.5 ft/sec; 2 ft/sec represents a midpoint of the higher speeds, and 0.5 ft/sec represents a mid-point of the slower speeds and is about as slow as a person can walk with reasonable consistency. For more information about the accuracy of the Swoffer 2100 current meter, see: Fulford, J.M., 2001. Accuracy and consistency of water-current meters. Journal of the American Water Resources Association 37:5, pp. 1215-1224.)

4) If you are in a pool with a filter/pump which creates a current, ask the pool managers if they can turn off the pump. If that is not possible, it is okay to calibrate while the pump is running as long as you start over with any back-and-forth pair of trials (i.e., #1-2; 3-4; 5-6; 7-8) if the pump starts or stops during that pair.

5) Any unit with an average count of below 170 for a 10-foot run (or 340 for a 20-foot run) should be repaired or replaced as necessary (see the “Troubleshooting” section below) and then recalibrated.

6) For every 10 rotor/prop units tested, perform a replicate set of trials.

7) Calculate calibration numbers for each unit using the Streamkeepers calibration spreadsheet. If the replicate set differs by more than 1% from its original set, redo the calibration. Store a copy of the calibration spreadsheet in the rear pocket of the calibration binder.

8) The spreadsheet will assign the units with the highest calibration numbers as primaries, and the others as spares.

9) Each rotor/prop unit should go into a bag marked with its kit and unit numbers, its calibration number and date, and whether it is a Primary or Spare. Also make sure each bag has a 1/16” Allen wrench, needed to mount the unit.

10) Set the calibration number for each field kit’s meter to match the calibration number of its Primary rotor/prop unit, following instructions at the Swoffer web site. At the same time, make sure that the two screws at the bottom of the meter and the four screws on the back are all secure.

11) Record the calibration activity in the “Maintenance & Calibration” binder.

FIELD CHECK OF ROTOR/PROP UNITS:

Each time the unit is used in the field, it should be tested for snugness of the shaft and freedom of spin. See the hand-spin and blow-spin tests described in the Flow field protocol.

MAINTENANCE OF FIBER OPTICS (as needed or at the end or beginning of each monitoring season):

Check the four fiber-optic “eyes” in the bottom of the rotor and the two photo-optic “eyes” at the end of the sensor boom on the wand. If necessary, clean with soap and water and a soft toothbrush.

TROUBLESHOOTING THE ROTOR/PROP UNIT:

If you need to replace parts as described below, you may need to recalibrate the rotor/prop unit, depending on the nature of the problem requiring replacement:

1) If the prop has suffered significant damage, replace it.

2) If the rotor/prop unit fails the hand- or blow-spin test or the calibration number is below 170 (see above), here are some procedures you can perform:

a) Remove the Thrust-Bearing Nut at the front of the prop. Check the inside bottom of this nut; if a pronounced cup has formed where the rotor shaft spins against it, the nut should be replaced.

b) Remove the steel shaft. If it is dirty, clean it as described above. If it is very scored or doesn’t roll smoothly on a flat surface (with the little o-ring hanging off the edge), it should probably be replaced.

c) The rotor itself is virtually impossible to inspect, but you can try to clean it as described above.

d) If you’ve performed the above and the unit still fails the spin tests or continues to calibrate below 170, you probably need to replace just the rotor piece, which is probably scratched up inside. (It is good to have a couple of extra rotor pieces—and probably the others as well—on hand.) By switching in replacement pieces, you can tell which pieces need to be replaced.

MAINTAINING THE SWOFFER ADJUSTABLE WAND:

1) Each time a kit returns from the field, take out the wand, extend it fully, and allow it to dry before storage, if time permits.

2) Repair or replace the tell-tail if necessary (see Flow field protocol for description).

3) If the wand becomes difficult to slide up and down, it probably has dirt or an oxide buildup. In either case, clean the shaft with 00 or 000 steel wool. The inside of the outer shaft can be cleaned with a gun-cleaning rod and a brass brush of .375 caliber. If movement is still difficult, try mineral oil or butcher’s wax.