Scientific Analytical Calorimeter Solutions

Automatic Oxygen Filling

The following information applies to the : CAL3K-AP

The CAL3K_AP is connected to the oxygen supply and will FILL the vessel automatically. It will also DEFLATE the vessel. The process is monitored by the microprocessor.

The mechanical components for FILLING are (in direction of oxygen flow):

  1. Bulkhead oxygen connector
  2. Filter
  3. Inflate valve
  4. Throttle restrictor
  5. Filling head
  6. Pressure sensor
  7. Vessel

The mechanical components for DEFLATING are (in direction of oxygen flow):

  1. Vessel
  2. Pressure sensor
  3. Exhaust restrictor
  4. Exhaust valve
  5. Bulkhead exhaust connector
CAL3K-AP Oxygen Bomb Calorimeter System | DDS Calorimeters

All of the above components have O-rings for sealing, but the following O-rings require special mentioning:

Vessel main Lid seal, 48x5 Part Number 3K-4-LR
Vessel Lid/Nipple seal Part Number 3K-4-VNR
Filling head Seal, 8x2 Part Number……………
Universal quick connect seal Part number 3K-4-LR

The parameters which control the filling are:

Parameter Description Default
Fill target The nominal filling pressure 30bar
Fill Overshoot The allowed overshoot to reach the target 1.2bar
Fill Minimum The lowest acceptable filling pressure 26bar
Filling Time The nominal filling time in seconds 60s
Max filling Time The maximum filling time in seconds 90s

The mechanical components must work together with the electrical (parameters). To this end all valves and their performance are checked (User test) and the oxygen filling progress is monitored.

One of the critical operations is the LEAK detection. If the vessel (or connections under vessel pressure) leak then energy is lost, and the result will be lower than expected.

The following tests are checking the functionality of the filling/deflating components:

TEST13: Inflate valve connection and drive
TEST14: Exhaust valve connection and drive
TEST28: Vessel Inflate
TEST29: Vessel Deflate

For details see: USER TEST

A LEAK TEST is available from the CAL3K keyboard.

The filling procedure takes place during the Initial stage. It starts when everything has been checked during the Preparation stage and the Initial time starts.

  1. T0: The inflate valve opens
  2. T30: If filling done: M200, Warning, filling to fast
  3. T30: If pressure less than 5 bar: M202, Bottle closed, Abort
  4. T30: If pressure less than Fill Minimum/2: M204, Warning, Filling too slow
  5. T60: If pressure less than Target/2: M206, Filling too slow
  6. T90: If pressure is within Target-1bar: OK
  7. T90: If pressure less than Fill Minimum: M208, Pressure too low, Abort
  8. T90: If pressure greater Fill Minimum: M210, warning
    1. WHERE: T60=Filling time, default 60 seconds
    2. T90=Max filling time, default 90 seconds

The filling progress is displayed during the above process!

The oxygen supply bottle pressure affects the filling speed. For safety concerns the bottle pressure should be set 1.5 bar above the target pressure!


The broad term "Not Filling" can be dissected into the following scenarios: Filling too slow : The vessel pressure does not reach target within 40 to 60 seconds. Replace the restrictor, or The filling pressure stays at zero during the filling process. The CAL3K-AP has a "DEFLATE" keyboard command, which opens the oxygen inlet valve. It is used to deflate the oxygen line when the oxygen bottle is closed.

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The oxygen bottle is connected to the filling station via a pressure reduction regulator, which reduces the bottle pressure to 30bar. The pressure can be adjusted. Open the oxygen bottle valve and observe that the oxygen pressure indication on the filling station rises to 30 bar.

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The CAL3K_AP has a built in USER test which should be exercised once a day or after every power up. The test performs the indicated steps and the operator is asked to participate as indicated below. Each test step is displayed and HELP is available on every step.

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