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Caution
It is mandatory to remove the gag after
installation and before use.
With the gag in place the valve cannot
open.
Caution
The disc cannot be lifted when the vessel
is under vacuum.
Caution
• Before starting to disassemble the
valve, be sure that there is no steam
pressure in the drum or header.
• Parts from one valve should not be
interchanged with parts from another
valve.
Atmospheric relief valve type 1100
Installation and maintenance instructions
Outlet Piping
Back pressures built-up by discharge flow affect the operation of safety valves. Where possible, a
short vertical pipe connected through a long radius elbow discharging directly into the atmosphere
is the most desirable type of outlet piping. Such discharge piping should be at least the same size
as the valve outlet. Sectional area of the discharge pipe must never be less than the full area of the
safety valve outlet and shall be as short as possible to avoid undue stresses on the valve.
The exhaust piping should be as straight as possible and without any shut-off device.
When required, low point drains shall be provided in the discharge pipe. Drain pipes should be
collected to the main collector and shall be designed to avoid flow return into the valve.
If a silencer is used on a safety valve, it should have sufficient outlet area to prevent back pressure
from interfering with the proper operation and discharge capacity of the valve. The silencer or
other piping components should be constructed so as to avoid the possibility of creating corrosion
deposit restrictions in the steam passages.
Site erection
The valve must be installed vertically, spring up.
Fit the inlet/outlet mating flanges to the valve. The NPS of inlet/outlet pipes must be the same as
the valve.
As shown in Figure 2, the valve body is provided with two threaded connections for water ring
supply and overflow.
Remove the plugs (25) and connect inlet and outlet pipes to the valve body (1) in order to feed the
water ring as shown in Figure 2.
Connect upper water ring connection to a drain pipe.
Start-up
Remove the gag (50) that locks the disc onto the seat.
Check the disc operability using the lift lever (41).
Check water feeding of the water ring. It is recommended to feed the water ring with a constant
stream of water to compensate water vaporization.
7. Maintenance - repairing
Seat tightness and water ring
The valve seat tightness is provided using an elastomer rubber seal for the disc in contact with a
316L stainless steel nozzle. The soft material is bonded with a specific groove machined onto the
disc by high temperature with high pressure molding process. Therefore, the soft material is totally
adherent to the disc metal and cannot be replaced.
If the valve is equipped with a visual indicator as shown in Figure 2, the water level should be
regularly checked in order to ensure that the water flow is sufficient and properly adjusted.
Periodic inspection
Sapag strongly recommend that Atmospheric Relief Valves be opened at least once every six
months using the lift lever, preferably at more frequent intervals, and at any time the unit is down
for periodic inspection.
We also urge that valves be opened, internally inspected and cleaned, if necessary, during the
regular turbine or condenser inspection.
Disassembly instructions
The type 1100 Sapag safety valve can be easily disassembled for inspection or replacing internal
parts.
Refer to Figure 1 for the following disassembly instructions:
1.
Unscrew and remove the two lever axles (42).
2. Remove the lever (41) from the cap (40).
3. Remove the cap bolts (24) and then remove the cap (40).
4. Unscrew and remove both release lock nut (22) and release nut (21) from the spindle (14).
5. Refer to Figure 3 to measure using a depth micrometer and record dimension L between the
top of the adjusting bolt (11) and the topside of the body (1), as this information will be required
to correctly reassemble the valve.
6. Loosen and unscrew the adjusting bolt nut (12) in order to unscrew the adjusting bolt (11) until
it becomes free.
7. Loosen and remove the body-nozzle bolts (20).
8. Using suitable lifting means carefully lift the body (1) over the spindle (14), and away from the
valve.
9. Remove the body-nozzle gasket (3).
10. If applicable, unscrew and remove both pre-compression lock nut (32) and pre-compression
nut (31) from the spindle (14).
11. Remove the upper spring washer (10).
12. Using suitable lifting means carefully lift the spring (9) over the spindle (14), and away from the
valve.
Pentair reserves the right to change the contents without notice
ETS-07002-EN
page 3
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