Data Sheet
Bulletin 71.4:66
4
Table 1. Spring Selection for Type 66R Relief Set Pressure Ranges
BODY
SIZE,
NPS (DN)
CONSTRuCTION RELIEF SET PRESSuRE RANGE
SPRING
PART
NuMBER
SPRING COLOR
SPRING
DIAMETER,
SPRING
FREE
LENGTh,
2 (50)
Standard
2 to 8-inches w.c. (5 to 20 mbar)
6 to 16-inches w.c. (15 to 40 mbar)
11-inches w.c. to 1 psig (27 mbar to 0,07 bar)
0.75 to 1.5 psig (0,05 to 0,10 bar)
1 to 2 psig (0,07 to 0,14 bar)
1D765427012
1D765527012
1D765627032
1D765727032
1D765827032
Pink Stripe
Blue Stripe
Green Stripe
Red Stripe
Unpainted
0.120 (3,05)
0.138 (3,51)
0.177 (4,50)
0.207 (5,26)
0.225 (5,72)
6.00 (152)
6.00 (152)
6.00 (152)
6.09 (155)
6.00 (152)
Special
1.5 to 3 psig (0,10 to 0,21 bar)
3 to 5 psig (0,21 to 0,34 bar)
1D962627032
1N506427142
Unpainted
Black Stripe
0.262 (6,66)
0.283 (7,19)
6.25 (159)
6.31 (160)
3 (80)
Standard
2 to 8-inches w.c. (5 to 20 mbar)
6 to 16-inches w.c. (15 to 40 mbar)
11-inches w.c. to 1 psig (27 mbar to 0,07 bar)
0.75 to 1.5 psig (0,05 to 0,10 bar)
1 to 2 psig (0,07 to 0,14 bar)
1D770727012
1D770827032
1D765727032
1D765827032
1D770927032
Olive Green Stripe
Red and Yellow Stripe
Red Stripe
Unpainted
Blue and Yellow Stripe
0.135 (3,43)
0.162 (4,12)
0.207 (5,26)
0.225 (5,72)
0.283 (7,19)
6.00 (152)
6.00 (152)
6.09 (155)
6.00 (152)
6.06 (154)
Special
1.5 to 3 psig (0,10 to 0,21 bar)
3 to 5 psig (0,21 to 0,34 bar)
1E204427032
1N506527142
White and Red Stripe
Brown and Purple Stripe
0.306 (7,77)
0.363 (9,22)
6.38 (162)
6.38 (162)
4 (100)
Standard
2 to 8-inches w.c. (5 to 20 mbar)
6 to 16-inches w.c. (15 to 40 mbar)
11-inches w.c. to 1 psig (27 mbar to 0,07 bar)
0.75 to 1.5 psig (0,05 to 0,10 bar)
1 to 2 psig (0,07 to 0,14 bar)
1D771027012
1D771127032
1D527627032
1D771227032
1D771327032
Orange and Yellow Stripe
Light Blue Stripe
Gray and White Stripe
Pink and Blue Stripe
Silver Stripe
0.135 (3,43)
0.177 (4,50)
0.225 (5,72)
0.262 (6,66)
0.283 (7,19)
7.75 (197)
7.94 (202)
7.75 (197)
7.75 (197)
7.75 (197)
Special 1.5 to 3 psig (0,10 to 0,21 bar) 1E204527032 Pink Stripe 0.331 (8,41) 7.53 (191)
Inlet pressure registers under the diaphragm and is
opposed by the spring (Figure 2). When the inlet
pressure increases above the spring setting, the valve
plug opens in a throttling manner and relieves the
inlet pressure. As inlet pressure drops back to set
pressure, the spring closes the valve plug.
Inlet pressure registers on the bottom of the pilot
diaphragm through the upstream control line and
bleeds through a xed restriction in the pilot (Figure 2)
to provide loading pressure that helps the main valve
spring keep the main valve plug tightly shutoff. When
inlet pressure exceeds the setting of the pilot spring,
the pilot diaphragm moves upward, opening the pilot
valve disk and relieving some of the pressure from the
top of the main valve diaphragm. At the same time,
the inlet pressure increase registers on the bottom of
the main valve diaphragm.
The pressure differential acting on the main valve
diaphragm moves this diaphragm upward, opening
the main valve. Further increases in inlet pressure
continue to open the pilot valve disk and the main
valve plug. When inlet pressure returns to the pilot
control spring setting, the pilot disk closes, allowing
inlet pressure to load the top of the main valve
diaphragm through the xed restriction.
This equalizes the pressures acting on this diaphragm,
and the main valve spring closes the main valve plug.
Table 2. Type Y695RR Pilot Control Spring Selection
MAIN VALVE
CONSTRuCTION
RELIEF SET PRESSuRE RANGE
PILOT CONTROL SPRING
Standard
4 to 9-inches w.c. (10 to 22 mbar)
(1)
5 to 15-inches w.c. (12 to 37 mbar)
(1)
12 to 28-inches w.c. (30 to 70 mbar)
(1)
0.9 to 2.5 psig (0,06 to 0,17 bar)
1.3 to 4.5 psig (0,09 to 0,31 bar)
1B653827052
1B653927022
1B537027052
1B537127022
1B537227022
Red
Cadmium
Yellow
Light green
Light blue
0.085 (2,16)
0.105 (2,67)
0.114 (2,90)
0.156 (3,96)
0.187 (4,75)
3.625 (92,1)
3.750 (95,3)
4.188 (106)
4.060 (103)
3.938 (100)
Special 3.8 to 7 psig (0,26 to 0,48 bar) 1B537327052 Black 0.218 (5,54) 3.980 (101)
1. Published ranges are with the spring case pointed up.