Pressure Loaded Construction
The spring case can be pressure loaded to adjust outlet
pressure. An optional tapped spring case, guide ring seal
and sealing washer on the adjusting screw must be used for
these applications. The loading pressure is connected to the
1/4 NPT connection in the spring case allowing registration
on the spring side of the diaphragm. Adjusting loading
pressure will proportionally change the outlet pressure
setting of the regulator. A small amount of mechanical spring
load, in addition to the pressure load, is recommended.
Regulator set pressure achieved from the combination of
spring load and pressure load should not exceed the outlet
pressure ranges listed in Table 2.
Overpressure Protection
The recommended pressure limitations are stamped on
the regulator nameplate. Some type of overpressure
protection is needed if the actual inlet pressure exceeds the
maximum operating outlet pressure rating. Overpressure
protection should also be provided if the regulator inlet
pressure is greater than the safe working pressure of
downstream equipment.
Startup
The regulator is factory set to the midpoint of the spring range.
To change the setpoint, refer to the Adjustment section for
directions.
Make sure the CIP/SIP Pin (key 30, Figure 4) is not
installed in the spring case.
See the section on Clean in Place
or Steam in Place (CIP/SIP). With proper installation completed
and relief valves properly adjusted (when applicable), slowly
open the upstream and downstream shutoff valves.
!
WARNING
The CIP/SIP pin must be removed before
regulator is placed in operation. The pin will
inhibit the proper operation and function of
the regulator, a result in overpressure of the
downstream system.
Table 3.
Maximum Differential Pressures
BODY SIZE
PRESSURE RANGE
COLOR
MAXIMUM
DIFFERENTIAL PRESSURE
In.
mm
psig
bar
psid
bar d
1/2, 3/4, 1 and 1-1/2 x 1
15, 20, 25 and 40 x 25
2 to 8
0.14 to 0.55
Blue
50
3.4
5 to 25
0.34 to 1.7
Silver
75
5.2
10 to 50
0.69 to 3.4
Green
100
6.9
25 to 90
1.7 to 6.2
Red
125
8.6
35 to 135
2.4 to 9.3
Red/Yellow
125
8.6
1-1/2
full port
40
full port
5 to 25
0.34 to 1.7
Silver
75
5.2
10 to 50
0.69 to 3.4
Green
100
6.9
25 to 75
1.7 to 5.2
Red
125
8.6
35 to 100
2.4 to 6.9
Green/Yellow
125
8.6
2 and 3
50 and 80
10 to 25
0.69 to 1.7
Silver
60
4.1
15 to 50
1.0 to 3.4
Green
120
8.3
25 to 75
1.7 to 5.2
Red
130
9.0
Note
When the pressure load option is used,
always open block valves on main line before
applying loading pressure to the spring case
to avoid diaphragm damage.
Adjustment
The setting of the regulator can be varied within the pressure
range stamped on the nameplate. It is important to have
a nominal amount of downstream demand while adjusting
the setpoint. Typically 5 to 10% of maximum capacity is
adequate. To change the outlet pressure, loosen the locknut
(key 17, Figure 4) or locking lever (key 22, Figure 4) and
turn the adjusting screw (key 18, Figure 4) clockwise to
increase outlet pressure or counterclockwise to decrease
it. Monitor the outlet pressure with a test gauge during the
adjustment. Tighten the locknut or locking lever to maintain
the desired setting. All regulator springs can be backed off to
provide zero outlet. Available spring ranges, recommended
maximum allowable differential pressures and spring data
are shown in Tables 2 and 3.
Shutdown
Close the upstream shutoff valve. Close downstream shutoff
valve. Open the bleed valve between the regulator and
the downstream shutoff valve. Without changing regulator
spring adjustment, all pressure between the upstream
and downstream shutoff valves is released through the
bleed valve, since the regulator opens in response to the
decreased outlet pressure.
Note
When the pressure loaded option is
used, bleed all pressure from the spring
case before bleeding pressure under the
diaphragm to avoid internal part damage.
4
Type SR5
