User Guide
DPU RECORDER INITIAL START-UP
Due to possible periods of storage prior to installation, the DPU bellows may take a "set". Therefore, it is recommended
that the first time the DPU is used, and prior to actual operation, the instrument be exercised to ensure correct operation.
To exercise the DPU, apply maximum and minimum pressure to the high pressure side for at least ten cycles.
DPU RECORDER GENERAL PRACTICES
Observe the following practices when starting operation of the instrument:
1. Always start with the block valves closed.
2. Perform a zero check of the instrument by equalising the pressure to both sides of the DPU and if necessary zero
the pen to the correct chart reading.
3. Check manifold and piping for any leaks.
4. Do not subject the DPU to unnecessary pressure shock or over-range during start-up.
FITTING A CHART
Clearscan charts are 12" (300mm) nominal diameter printed on to temperature and humidity stable 7-point paper.
Mechanical Clock (Note: clocks up to 24 hour rotation have combined chart clamp winder, rotations above 24 hour have a
separate clamp and winder)
Release the chart clamp as follows (please refer to the chart drive section for information on other chart drive types):
1. Unscrew to remove the winder clamp from the clock hub
2. Operate the pen lifter to raise the pen arm(s)
3. Slide the chart under the pen lifter and pen arm(s) and locate the chart centre hole over the clock hub
4. Place the chart beneath the outer chart clips.
5. Align the red pen with the correct timeline on the chart. On a two-pen instrument the blue pen will be 4mm in
advance of the red pen.
6. Refit the winder clamp.
INKING SYSTEM
The writing system uses fibre tip pen capsules.
Where there are two or more measuring systems, different colour inks are used to distinguish the traces.
The fibre tip is protected by a rubber cap, which should be removed by pulling in line with its length, gripping the end only
and gently twisting.
The capsule accepts the steel pen arm and a clamp provided on the capsule to secure itself to the pen arm.
The first pen is coloured red, whilst the second pen is blue.
9