Cashco 1000 HP Differential - Manual (Page 2)

2 IOM-1000HP-Dif fer en tial
∆P
Sizing
= P
1
- P
2
P
2
> P
Load
P
2
= P
Load
+ P
Set
∆P
Differential
= P
2
- P
Load
diaphragm design): Regulator may be rotated
around the pipe axis 360° and may be installed
in a horizontal or vertical pipeline.
12. Regulators are not to be direct buried un der -
ground.
10. For best performance, install in well drained hor-
i zon tal pipe, properly trapped if a steam ser vice
ap pli ca tion.
11. Differential Regulator – (Refer to Dwg. Opt-1+6
for single diaphragm or Dwg. Opt-1+8 for double
SECTION III
III. PRINCIPLE OF OPERATION
1. The differential Model 1000HP is also available
in two options: 1000HP-1+6 is single diaphragm
con struc tion; 1000HP-1+8 is double diaphragm
con struc tion. The dou ble diaphragm construction
prevents the loading fl uid from direct mixing with
the system fl uid in case of di a phragm failure.
2. Movement occurs as pressure variations register
on the diaphragm. One pressure is the outlet (p
2
)
or down stream pressure, which registers on the
“un der neath” side of the diaphragm. The second
pressure reg is tered is the loading (P
Load
) pres sure
in the spring chamber “above” the di a phragm. The
range spring determines the differential pres sure
level (P
Set
). As outlet (P
2
) pressure drops, the
range spring pushes the diaphragm down, open-
ing the port; as outlet (P
2
) pressure in creas es,
the diaphragm pushes up and the port closes.
As the loading (P
Load
) pressure varies, the outlet
(P
2
) pressure tends to follow. An increase in P
Load
(∆P
Load
) will increase outlet P
2
pressure by near ly
an equal amount (∆P
Load
= ∆P
2
); a decrease in
P
Load
will have a similar effect on outlet P
2
pres-
sure.
3. The Model 1000 includes a rocker arm in its op-
eration mechanism. The rocker arm allows the
regulator to op er ate fl ow-to-open (FTO), rather
than conventional fl ow-to-close (FTC), which
in creas es rangeability.
4. Due to the FTO design, there is a limit as to how
low of a downstream (P
2
or outlet) pressure level
setting is capable for a given inlet P
1
pressure.
This is a function of the ratio of the port area to the
diaphragm area. It is possible for there to be too
high of an inlet pressure for the regulator to close
off against. (Refer to 1000HP-DIFF-TB, Ta bles 9,
10, 11 and 12 for limits.) Reduced port, Opt-12,
allows lower down stream (P
2
or outlet) pres sure
settings for a given upstream (P
1
or inlet) pressure
level.
5. The Model 1000 includes an aspiration jet effect,
due to the clearance of the piston from the body
near the outlet. These clearances vary as to
whether the fl uid is a gas (including steam), a liquid,
or a viscous liquid (required Opt-27). Jets must
be selected to match one of these three general
fl uids. An improper jet will reduce per for mance.
NOTE: The regulator requires minimum output
pressure level or the regulator will not close.
LOADING
FLUID @ P
Load
RANGE SPRING:
SETTING @ P
Set
Diaphragm
OUTLET
@ P
2
& T
2
1000HP-1+6
DIFFERENTIAL SCHEMATIC
6. For a 1000HP-1+6 (single diaphragm) design, a
com plete diaphragm failure will cause the fl uids
to mix in the spring chamber or loading pressure
piping system.
7. For a 1000HP-1+8 (double diaphragm) design, a
complete diaphragm failure will cause the reg u la tor
to fail open, leaking fl uid through the annular ring
vent hole.
NOTE: Composition (soft) diaphragms may be
utilized only on -1+6 single diaphragm con struc-
tion.
8. For viscous fl uids normally heated (heavy fuel
oil), it may be desirable to include a fl ow-through
spring cham ber, the -65 Option.