Table of Contents
Advertisement
CROSBY SERIES HE ISOFLEX
INSTALLATION, MAINTENANCE AND ADJUSTMENT INSTRUCTIONS
Disassembly
(without retaining spring compression)
If it is desired to disassemble the valve
completely and not retain the spring
compression, the following procedure should
be used:
1. Measure the distance from the top of
the adjusting bolt to the machine bonnet
surface. This measurement will be
necessary when the valve is reassembled.
2. Release spring tension by loosening the
adjusting bolt locknut (27) and then the
adjusting bolt (26).
CAUTION
Never loosen the bonnet stud nuts (19) before
releasing spring tension with the adjusting bolt (26).
3. Remove the guide ring set screw (11) and
the nozzle ring set screw (4).
4. Loosen and remove the bonnet stud nuts (19).
5. Using an eyebolt threaded onto the spindle,
lift the assembled superstructure straight
up and out of the body.
CAUTION
Do not permit any rocking motion of the spindle
or of any parts while lifting the superstructure out
of the body. Any rocking motion could damage the
seats.
6. Lay the superstructure down so that
the spindle is in the horizontal position.
Care must be exercised to prevent the
parts from being damaged while laying
the superstructure down.
7. Remove the eyebolt from the spindle and
slide the internals (disc holder, insert,
eductor, guide ring, and spindle) carefully
out of the spring and bonnet assembly.
8 REPAIR PROCEDURE
When the valve is dismantled completely,
examine all parts for signs of wear, damage or
corrosion to determine if any replacement parts
are required. Particular care should be used to
examine the following parts:
• Insert (5)
- Seat (see Figure 8 for minimum dimension)
- Spindle bear surface on the inside of the
insert
- Land outside diameter which interfaces with
the disc holder
SELF-ACTUATED SAFETY VALVES
®
• Nozzle (1B)
- Seating surface
- Seat step (see Figure 8 for minimum
dimension)
- Outside diameter of lands that guide in
the eductor
- Inside diameter where the disc insert guides
- Inside diameter of eductor (9) where the
piston (13) guides
• Spindle (12)
- At bottom spring washer (21) bearing surface
- Where the spindle point bears on disc insert (5)
- The surfaces that pass through the
adjusting bolt (26) upper and over spring
washers (21 and 22) and disc holder (6).
If replacement parts are required, refer to
paragraph 'Spare parts'.
Lapping of the valve seats
Good seating surfaces on the nozzle (1B) and
disc insert (5) are of the greatest importance
when reconditioning safety valves.
The seats should always be flat and free from
surface scratches.
• Lapping block (see Figure 9)
This is made of a special grade of annealed cast
iron, perfectly flat on both sides. It is essential
that it remain flat to produce a truly flat seating
surface. In checking the lapping block and for
restoring flatness after its use, a lapping block
reconditioner should be used.
• Lapping block reconditioner (see Figure 9)
This is also made of a special grade of annealed
cast iron, machined and lapped on the side
which has small squares. This is the surface on
which the lapping blocks are reconditioned.
11
Advertisement
Table of Contents
