13
Disassembly
When disassembling or removing the product, wait until the internal
pressure equals atmospheric pressure and the surface of the product
has cooled to room temperature. Disassembling or removing the
product when it is hot or under pressure may lead to discharge of fluids,
causing burns, other injuries or damage.
CAUTION
It is a recommended practice to dismantle and inspect the PN-DR once a year for
preventive maintenance purposes. It is especially important to perform an inspection
immediately after the initial run of a new line or before or after equipment such as a
heater is out of service for a long period of time. (Installation, inspection,
maintenance, repairs, disassembly, adjustment and valve opening/closing should be
carried out only by trained maintenance personnel.)
Remove all steam/pressurized air from the piping (both upstream and downstream).
Remove all motive air pressure.
Wait for the body to cool before attempting to remove the PN-DR from the line. Then
remove the PN-DR from the piping, and secure it in a vise to perform the inspection.
Dismantling the Adjusting Section
Loosen the adjustment handle completely and remove the cover bolts. After
removing the cover, you will see the steel ball, the spring retainer and the coil spring.
Check for seizure or any damaged screw threads.
Remove the retaining ring. The seal ring and the packing can be removed by
loosening the adjustment handle and the holder nut.
Check and make sure that the seal ring is not deteriorated and the packing has no
abnormality.
Retaining Ring
Steel Ball
Spring Guide
Coil Spring
Cover Bolt
Cover
Retainer
Cover Gasket
Packing
Seal Ring
Holder Nut
Adjustable Handle
172-65119MA-01 (PN-DR) 13 Jun 2013
