Cashco SAP - Manual (Page 2)

IOM-SAP 2
IV. PRINCIPLE OF OPERATION
1. When a loading pressure – P
Load
– is applied to the
top side of a guide bearing, the outlet controlled
pressure – P
2
– will balance at approximately
.90 – .98 of the loading pressure - P
L
. (NOTE:
Fluc tu a tions in P
1
– Inlet Pressure will cause a
deviation in P
2
– Outlet Pressure due to inverse
sym pa thet ic ratio effect.)
V. STARTUP
1 Start with the block valves closed.
2. Adjust the loading system pressure control de vice
so that main regulator is trying to be con trolled at
0 psig pressure.
3. If it is a “hot” piping system, and equipped with
a bypass valve, slowly open the bypass valve
to preheat the system piping and to allow slow
ex pan sion of the piping. Closely monitor outlet
(down stream) pressure via gauge to ensure not
over-pressurizing. NOTE: If no bypass valve is
in stalled, extra caution should be used in start ing
up a cold system; i.e. do everything slowly.
SECTION VI
tor is fl owing. If not, slowly increase the loading
pressure into the cover dome until fl ow be gins.
6. Continue to slowly open the inlet (upstream) block
valve until fully open.
7. Continue to slowly open the outlet (downstream)
block valve, especially when the downstream
piping system isn’t pressurized. If the outlet pres-
sure exceeds the desired pres sure, close the inlet
block valve and go to Step 2. Close bypass valve
approximately 25%, and re peat pro ce dure.
8. When fl ow is established steady enough that the
outlet (downstream) block valve is fully open, begin
to slowly close the bypass valve if installed.
9. Develop system fl ow to a level near its expected
normal rate, and reset the regulator set point by
increasing the loading pressure to increase outlet
pressure, or decreasing the loading pressure to
reduce outlet pres sure.
10. Reduce system fl ow to a minimum level and ob-
serve pressure set point. Outlet pressure will rise
from the set point of Step 9. The maximum rise
in outlet pressure on decreasing fl ow should not
exceed the stated upper limit of the range spring
by greater than 10%. If it does, consult factory.
SECTION IV
SECTION V
2. Movement occurs as pressure variations register
on the guide bearing. The registering pressure is
the outlet, P
2
, or downstream pressure. The load-
ing pressure fl uid op pos es upward move ment.
As outlet pres sure drops, the loading pressure
push es the guide bearing down, opening the port;
as outlet pres sure increases, the guide bearing
pushes up and the port opening closes.
3. A loss of loading pres sure while inlet pressure is
imposed will cause the regulator to fail close.
4. Crack open the outlet (downstream) block valve
to approximately 10% full open.
5. Slowly open the inlet (upstream) block valve to
about 25% open, observing the outlet (down-
stream) pres sure gauge. Determine if the reg u la-
CAUTION
Do not walk away and leave a bypassed reg u -
la tor unattended!
VI. SHUTDOWN
1. Shutoff auxiliary loading pressure source. Close
inlet block valve.
2. Allow suffi cient time for the line pressure down-
stream of the inlet block valve to bleed down.
3. Close the outlet block valve.
4. Relieve the trapped upstream and down stream
pres sure and any loading pres sure.
5. The regulator may now be disassembled for
inspection and pre ven ta tive main te nance while
in-line.