Flexflo 887 Series Surge Reliever Manual | 5
Copyright 2020 Baker Hughes Company. All rights reserved.
Tube Differential Pressure – Flexflo Surge Reliever
Table 1
Valve Size
inches (mm)
Tube/Durometer
ASME Class
DF Minimum
75°F (23.9°C)
psid (bard)
DF Maximum
75°F (23.9°C)
psid (bard)
DF Minimum
0°F (-17.8°C)
psid (bard)
DF Maximum
0°F (-17.8°C)
psid (bard)
4 (100)
ECO 725/40
150
3 (0.2)
7 (0.48)
17 (1.17)
23 (1.58)
4 (100)
ECO 893/50
150
5 (0.34)
13 (0.90)
20 (1.38)
27 (1.86)
4 (100)
ECO 878/65
300
12 (0.83)
30 (2.07)
27 (1.86)
48 (3.31)
4 (100)
NBR 846/75
600
20 (1.4)
51 (3.52)
30 (2.07)
66 (4.55)
6 (150)
ECO 725/40
150
3 (0.2)
6 (0.41)
17 (1.17)
21 (1.45)
6 (150)
ECO 893/50
150
5 (0.34)
12 (0.83)
19 (1.31)
26 (1.79)
6 (150)
ECO 878/65
300
11 (0.76)
28 (1.93)
26 (1.79)
43 (2.96)
6 (150)
NBR 846/75
600
19 (1.31)
46 (3.17)
24 (1.65)
60 (4.14)
8 (200)
ECO 725/40
150
2 (0.14)
5 (0.34)
16 (1.10)
20 (1.38)
8 (200)
ECO 893/50
150
4 (0.17)
9 (0.62)
18 (1.24)
23 (1.58)
8 (200)
ECO 878/65
300
9 (0.62)
22 (1.52)
23 (1.58)
38 (2.62)
8 (200)
NBR 846/75
600
10 (0.69)
23 (1.58)
13 (0.90)
40 (2.76)
10 (250)
ECO 725/40
150
2 (0.14)
5 (0.34)
16 (1.10)
20 (1.38)
10 (250)
ECO 893/50
150
4 (0.17)
9 (0.62)
18 (1.24)
24 (1.65)
10 (250)
ECO 878/65
300
9 (0.62)
23 (1.58)
23 (1.58)
39 (2.69)
10 (250)
NBR 846/75
600
10 (0.69)
24 (1.65)
23 (1.58)
41 (2.83)
12 (300)
ECO 725/40
150
2 (0.14)
5 (0.34)
14 (0.96)
20 (1.38)
12 (300)
ECO 893/50
150
4 (0.17)
9 (0.62)
18 (1.24)
23 (1.58)
12 (300)
ECO 878/65
300
9 (0.62)
23 (1.58)
23 (1.58)
39 (2.69)
12 (300)
NBR 846/75
600
10 (0.69)
24 (1.65)
23 (1.58)
41 (2.83)
4 (100)
HNBR 740/85
600
30 (2.07)
66 (4.55)
39 (2.69)
86 (5.93)
6 (150)
HNBR 740/85
600
24 (1.65)
65 (4.48)
31 (2.13)
83 (5.72)
8 (200)
HNBR 740/85
600
15 (1.03)
31 (2.13)
20 (1.38)
40 (2.76)
10 (250)
HNBR 740/85
600
15 (1.03)
30 (2.07)
20 (1.38)
39 (2.69)
12 (300)
HNBR 740/85
600
14 (0.96)
30 (2.07)
19 (1.31)
39 (2.69)
4 (100)
HNBR 744/75
300
20 (1.4)
51 (3.52)
35 (2.41)
66 (4.55)
6 (150)
HNBR 744/75
300
19 (1.31)
46 (3.17)
33 (2.27)
60 (4.14)
8 (200)
HNBR 744/75
300
12 (0.83)
28 (1.93)
26 (1.79)
42 (2.89)
10 (250)
HNBR 744/75
300
11 (0.76)
25 (1.72)
25 (1.72)
39 (2.69)
12 (300)
HNBR 744/75
300
11 (0.76)
24 (1.65)
25 (1.72)
41 (2.83)
4 (100)
HNBR 745/65
150
13 (0.90)
33 (2.27)
27 (1.86)
48 (3.31)
6 (150)
HNBR 745/65
150
12 (0.83)
30 (2.07)
26 (1.79)
45 (3.10)
8 (200)
HNBR 745/65
150
10 (0.69)
28 (1.93)
25 (1.72)
42 (2.89)
10 (250)
HNBR 745/65
150
9 (0.62)
23 (1.58)
23 (1.58)
37 (2.55)
12 (300)
HNBR 745/65
150
8 (0.55)
22 (1.52)
22 (1.52)
37 (2.55)
Note: NBR rubber increases in hardness with decrease in temperature. 40-70 durometer may increase by 14-16 points from
80°F (26.6°C) to 0°F (-17.8°C).85 durometer may increase by 6-9 points from 80°F (26.6°C) to 0°F (-17.8°C).
The following is a listing of the expected “Roll Up” pressures for the various tube materials. These differential pressures should be
used as a guide in setting the jacket pressure. Variations in part machining, tube characteristics and fluids may cause the “Roll Up” to
/- 5%.
DF Minimum: Minimum differential pressure to begin to open tube.
DF Maximum: Maximum differential pressure to fully open tube.
