Preventive Maintenance

Nitrogen-phosphorus detector (NPD)

Figure 8-17

Type A

Type B

 

Detector

Cover

Trans-

Brass Collar

Teflon Spacer

Transformer Strap

Steel Spring

Spacer

Collector

O-ring

Collector Body

NPD Collector and Collector Assembly

Whenever the collector must be removed from the detector cover of a Type A NPD, the following procedure should be used:

Note: During disassembly do not touch the lower portion of the collector assembly. Use clean, lint•freegloves to prevent contamination of the assembly. Suitable gloves (HP Part No. 8650•0030)are available.

1.Following the procedure under Cleaning, remove the collector assembly from the detector base. A 1.5•mmhex wrench is required for disassembly.

2.Loosen the setscrew in the brass collar at the top of the collector assembly. Remove the transformer lead from the collar; then remove the collar itself.

The remaining transformer lead does not need to be disconnected to remove the collector. However, if desired, it is easily removed by loosening the setscrew in the stainless steel portion of the collector body.

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