Table of Contents

Replacement of SCD Outer Pyrotube

Required devices¶

No.	Parts name	Category	Required number
①	Inner Pyrotube	Sulfur Chemiluminescence Detector (SCD)	1
②	PTFE Ferrule	Sulfur Chemiluminescence Detector (SCD)	1
③	Spanner, SCD, Maintenance	Sulfur Chemiluminescence Detector (SCD)	1
④	Spanner, SCD	Sulfur Chemiluminescence Detector (SCD)	1
⑤	Tweezers	Other	1
⑥	Outer Pyrotube	Sulfur Chemiluminescence Detector (SCD)	1
⑦	O-ring, 4D P3	Sulfur Chemiluminescence Detector (SCD)	1
⑧	Installing JIG for Inner Pyrotube	Sulfur Chemiluminescence Detector (SCD)	1

Procedures¶

Step 1¶

On the instrument monitor or workstation, check that the temperature of the column oven is lower than 40 °C, and check that the temperatures of the injection port and detector (SCD-IF part and electric furnace) are 50 °C or lower.
After checking the temperatures, turn OFF the main power to the instrument.

Step 2¶

Open the side cover.

Step 3¶

Remove the transfer line (★1).

While holding the transfer adapter (★2), loosen the transfer line (★1) and remove it.

Step 4¶

Remove the transfer adapter (★2) and inner pyrotube (①).

While holding the reductant inlet (★3) with a spanner, SCD (④), loosen the transfer adapter (★2) with a spanner, SCD, maintenance (③) and then remove the transfer adapter (★2) together with the inner pyrotube (①).

Hint

If you cannot remove the inner pyrotube with the transfer adapter, remove the inner pyrotube with tweezers.

Step 5¶

Loosen and remove the reductant inlet with a spanner, SCD (④).

Step 6¶

Remove the outer pyrotube (⑥) with tweezers (⑤).

Step 7¶

Install a new O-ring (⑦) on the outer pyrotube (⑥) for replacement.

Hint

Install the O-ring about 3 mm from the end.

Step 8¶

Insert the outer pyrotube (⑥) in the SCD.

Step 9¶

Ensure that the O-ring hits the back.

Check that it hits the back as shown in the following figure.

Note

When the O-ring does not hit the back, the end of the outer pyrotube interferes with the parts inside the SCD as shown in the following figure.

In this case, turn the outer pyrotube several times while pushing it against the back.

Step 10¶

Install the reductant inlet.

Tighten it by hands and then additionally tighten it with a spanner, SCD (④).

Step 11¶

Detach the transfer adapter from the inner pyrotube.

Step 12¶

Detach the PTFE ferrule (②) from the transfer adapter (★2) and remove the back ring (★4).

Hint

Removed back ring will be used in the step 14.

Step 13¶

Install a new PTFE ferrule (②) on the inner pyrotube (①) for replacement.

Step 14¶

Install the back ring removed in the step 12 on the inner pyrotube.

Step 15¶

Install the transfer adapter on the inner pyrotube.

Step 16¶

Insert the inner pyrotube with the transfer adapter attached into the SCD.

Step 17¶

Temporarily tighten the transfer adapter (★2) to the extent that it moves back and forth while exposing the tip of inner pyrotube (①).

Step 18¶

Push the end face of the inner pyrotube (①) into the back with the jig (⑧) and fix to the transfer adapter (★2).

Hint

Tighten the transfer adapter (★2) and jig (⑧) until the gap between them is about 2mm.

Step 19¶

With the jig (⑧) still attached, fix the transfer adapter (★2) to the SCD using a spanner, SCD, maintenance (③) and a spanner, SCD (④).

Step 20¶

Remove the jig (⑧) from the transfer adapter (★2).

Step 21¶

Check that the end face of inner pyrotube does not protrude from the transfer adapter (★2).
If it is protruding, re-install the inner pyrotube.

Step 22¶

Additionally tighten the transfer adapter.

After tightening it by hand until it does not turn anymore, give additional tightening of half turn with a spanner, SCD, maintenance (③).

Step 23¶

Install the transfer line by hand-tight.

Step 24¶

Close the side cover.

Step 25¶

Turn on the main power of the instrument and start the GC.

Note

After the SCD startup is completed, condition it for about 12 hours under the analysis conditions. After replacing the pyrotube, it takes time until the sensitivity is recovered.