Table 4.
Main Valve Minimum Differential Pressures
(1)
Principle of Operation
As long as the outlet (control) pressure is above
the outlet pressure setting, the pilot valve plug or
disk remains closed (Figure 2). Force from the main
spring, in addition to inlet pressure bleeding through
the Type 112 restrictor (the restrictor is integral in
the PRX Series pilots), provides downward loading
pressure to keep the main valve diaphragm and plug
assembly tightly shutoff.
When the outlet pressure decreases below the pilot
outlet pressure setting, the pilot plug or disk assembly
opens. Loading pressure bleeds downstream through
the pilot faster than it can be replaced through the
Type 112 restrictor. This reduces loading pressure on
top of the main valve diaphragm and plug assembly.
The force imbalance on the diaphragm allows the inlet
pressure to overcome the loading pressure and main
spring force and open the Type EZR diaphragm and
plug assembly.
As the outlet pressure rises toward the outlet pressure
setting, it compresses the pilot diaphragm against the
pilot control spring and allows the pilot valve plug or
disk close. Loading pressure begins building on the
Type EZR diaphragm and plug assembly. The loading
pressure, along with force from the main spring,
pushes the diaphragm and plug assembly onto the
tapered-edged seat, producing tight shutoff.
MAIN VALVE
BODY SIZE,
NPS / DN
MAIN SPRING PART
NUMBER AND
COLOR CODE
DIAPHRAGM
MATERIAL
MINIMUM DIFFERENTIAL, PERCENT OF CAGE CAPACITY
FOR 90% CAPACITY
FOR 100% CAPACITY
100% Trim
60% Trim
30% Trim
100% Trim
60% Trim
30% Trim
psi bar
psi
bar
psi
bar
psi
bar
psi bar
psi
bar
1 and 1-1/4 x 1 /
25 and 32 x 25
19B2400X012, Light Blue
17E68 and 17E88
24
1.7
29
2.0
31
2.2
24
1.7
31
2.2
40
2.8
GE12727X012, Black
17E97
35
2.5
38
2.7
42
2.9
35
2.5
39
2.7
52
3.6
17E68 and 17E88
30
2.1
35
2.4
39
2.7
30
2.1
36
2.5
52
3.6
19B2401X012,
Black with White Stripe
(3)
17E88 and 17E97
43
3.0
50
3.4
56
3.9
43
3.0
53
3.7
68
4.7
2 x 1 / 50 x 25
19B2400X012, Light Blue
17E68 and 17E88
24
1.7
29
2.0
31
2.2
24
1.7
31
2.2
40
2.8
19B2401X012,
Black with White Stripe
17E97
43
3.0
50
3.4
56
3.9
43
3.0
53
3.7
68
4.7
17E68 and 17E88
43
3.0
50
3.4
56
3.9
43
3.0
53
3.7
68
4.7
GE12501X012,
Red Stripe
(3)
17E97
68
4.7
73
5.0
88
6.1
72
5.0
81
5.6
102
7.0
2 / 50
19B0951X012, Yellow
(2)
17E68 and 17E88
12
0.83
15
1.0
15
1.0
12
0.83
25
1.7
20
1.4
18B2126X012, Green
17E97
24
1.7
25
1.7
26
1.8
24
1.7
30
2.1
37
2.6
17E68 and 17E88
18
1.2
20
1.4
22
1.5
19
1.3
26
1.8
28
1.9
18B5955X012, Red
(3)(4)
GE05504X012, Purple
(3)(4)
17E88 and 17E97
29
2.0
29
2.0
31
2.1
31
2.1
35
2.4
43
3.03
3 / 80
T14184T0012, Yellow
(2)
17E68 and 17E88
16
1.1
19
1.3
24
1.7
23
1.6
23
1.6
29
2.0
19B0781X012, Light Blue
17E97
23
1.6
23
1.6
23
1.6
23
1.6
23
1.6
25
1.7
17E68 and 17E88
21
1.5
22
1.5
28
1.9
28
1.9
28
1.9
33
2.3
19B0782X012, Black
(3)
17E88 and 17E97
32
2.2
33
2.3
43
3.0
38
2.6
38
2.6
50
3.4
4, 6 x 4 and, 8 x 4 /
100, 150 x 100
and 200 x 100
T14184T0012, Yellow
(2)
17E68 and 17E88
10 0.69
12
0.83
14
0.97
25
1.7
25
1.7
25
1.7
18B8501X012, Green
17E97
16
1.1
17
1.2
21
1.5
34
2.3
34
2.3
34
2.3
17E68 and 17E88
16
1.1
17
1.2
20
1.4
30
2.1
30
2.1
30
2.1
18B8502X012, Red
(3)
17E88 and 17E97
21
1.5
24
1.7
26
1.8
40
2.8
40
2.8
40
2.8
6, 8 x 6 and
12 x 6 /
150, 200 x 150
and 300 x 150
19B0364X012, Yellow
(2)
17E97
10
0.69
11
0.76
14
0.97
12
0.83
16
1.1
16
1.1
17E88
10
0.69
13
0.90
13
0.90
12
0.83
21
1.5
21
1.5
19B0366X012, Green
17E97
14 0.97
22
1.5
22
1.5
19
1.3
29
2.0
29
2.0
17E88
17
1.2
21
1.5
21
1.5
20
1.4
36
2.5
36
2.5
19B0365X012, Red
(3)
17E88 and 17E97
23
1.6
29
2.0
29
2.0
30
2.1
41
2.8
41
2.8
8 / 200
GE09393X012, Yellow
(2)
17E97
16
1.1
- - - -
- - - -
19
1.3
- - - -
- - - -
GE09396X012, Green
20
1.4
23
1.6
GE09397X012, Red
(3)
26
1.8
30
2.1
1. See Table 1 for structural design ratings, Table 3 for pilot ratings and Table 10 for maximum pressure ratings.
2. The yellow spring is only recommended for inlet pressures under 100 psig / 6.9 bar.
3. The red, black, purple, red stripe and black with white stripe springs are only recommended for applications where the maximum inlet pressure can exceed 500 psig / 34.5 bar.
4. 18B5955X012 (Red) is used on constructions with travel indicator while GE05504X012 (Purple) is used on non-travel indicator constructions.
4
Type EZR
