Parker Hannifin Corporation
Pneumatic Division Europe
www.parker.com/pde
3
FRL-SIF-120
_EU
Parker Pneumatic
Integration Guide
P33 Safety Exhaust Valve
Introduction
The function of the optional soft start module is to, on energization, allow outlet pressure to increase at a slower than
normal rate until it reaches approximately 60% of inlet pressure, at which point the valve will then open fully to finish
filling the system at full flow rate. This feature can be used to lessen the shock of sudden, rapid pressurization of
cylinders, and to gradually refill the system.
The soft start module has an adjusting screw that is used to control the rate of pressurization according to number of
turns and inlet pressure. The charts below can be used to approximate the number of turns (clockwise from full open)
it will take in order to adjust the soft start for your system. The necessary setting is dependent upon the number of
turns, inlet pressure, and downstream volume to be filled by the valve.
P33 Series Soft Start Adjustment - Flow vs Number of Turns and Inlet Pressure
Soft Start Adjustment Guide (Turns Versus Input Pressure)
Measured in Nominal L/Min
Turns
2 bar
4 bar
6 bar
8 bar
10 bar
0
158.28
259.37
366.97
487.88
551.31
2
464.94
785.48
1098.37
1384.93
1700.37
4
759.43
1279.03
1803.72
2235.83
2687.18
6
1061.56
1782.77
2459.81
3042.83
3771.69
8
1333.68
2190.80
3165.72
3913.27
4820.51
10
1574.93
2611.30
3669.18
4633.06
5597.50
Full Open
1594.47
2665.10
3769.70
4897.81
5833.94
Measured in SCFM
Turns
29 PSI
58 PSI
87 PSI
116 PSI
145 PSI
0
5.59
9.16
12.96
17.23
19.47
2
16.42
27.74
38.79
48.91
60.05
4
26.82
45.17
63.70
78.96
94.90
6
37.49
62.96
86.87
107.46
133.20
8
47.10
77.37
111.80
138.20
170.24
10
55.62
92.22
129.58
163.62
197.68
Full Open
56.31
94.12
133.13
172.97
206.03
