FILL AND BUILDUP TIME TEST

To perform the fill and buildup time test, it will be necessary to take the converter to a LOX servicing area, or use a LOX servicing trailer in the immediate area of the oxygen shop. Any other method is acceptable that meets requirements of the test, and does not violate safety precautions. Remember, LOX requires special precautions.

Once the converter is in a satisfactory location, proceed as follows:

1. Attach a vent drain line to the converter quick-disconnect coupling. This line should be long enough to route venting LOX away from all personnel.

2. Attach the pressure gauge/relief valve test fixtures to the supply quick-disconnect coupling (refer to NAVAIR 13-1-6.4).

3. Attach the servicing trailer filler valve to the converter fill, buildup, and vent valve.

4. Note the time, and start filling the converter. Maintain a filling pressure at 30 psig.

5. The converter is full when a steady stream of LOX flows from the drain line. When the converter is full, note the time. The time required to fill the converter at 30 psig should be no longer than 10 minutes. Record the fill time in the appropriate space on the Performance Test Sheet.

6. Note the time, and disconnect and secure the servicing trailer. The time noted at this point is the beginning of the buildup time test.

7. Observe the pressure gauge on the quickdisconnect coupling. On the performance test sheet, record the time it takes the converter assembly to buildup to a working pressure of 70 to 80 psig. This time should not exceed 5 minutes.

8. If discrepancies were noted in either part of the test, locate the probable cause using the troubleshooting chart (table 12-21).

9. Remove the vent drain line and the pressure gauge/relief valve test fixture you installed in steps 1 and 2.

CAPACITANCE TEST (FULL)

The capacitance test requires simultaneous use of the 50-pound scales and the quantity gauge capacitance type tester incorporated in the test stand. Ensure the scales are positioned close enough to the tester, then proceed as follows:

1. Place the full converter on the scales.

2. Using the test stand cable assembly, connect the upper terminals of the converter high and low capacitance cable assemblies to terminals A and B, respectively, of the liquid oxygen quantity gauge capacitance type tester.

3. Turn the power ON and allow the tester to warm up 10 minutes before proceeding.

4. Turn the CAPACITANCE RANGE SELECTOR knob to its 10X position.

5. Turn the FUNCTION SELECTOR knob to the CAPACITANCE (UUF) position.

6. Enter the total weight of the full converter in the space provided on the performance test sheet.

7. Subtract the tare weight of the converter from its total weight. Enter this figure on the Performance Test Sheet. This is the weight of LOX in the converter.

8. Using the formula given on the Performance Test Sheet, 2.33 x W + 124.7 = C(max), calculate the capacitance maximum (C-max). Use the weight of LOX for W. Enter the result of the calculation in the space provided.

9. Use the formula 2.25 x W + 122.3 = C(min) and calculate the capacitance minimum (C-tin) on the next line of the test sheet. Use the weight of LOX for W.

Table 12-21.-Troubleshooting (Fill and Buildup Time Test)

10. Observe and record capacitance reading from test stand capacitance gauge in space provided on Performance Test Sheet. Reading should be between C(max) and C(min).

11. If the test is not within these limits and the converter has not been purged in previous tests, there may be moisture in the sphere. Purge the converter and refill it with LOX, then repeat steps 1 through 11.

12. If the converter is still not within limits, condemn the converter.

13. Secure the tester and disconnect the cables from the converter and tester. If the converter passes capacitance test, carefully remove it from the scales and allow it to remain undisturbed for 1 hour.