Page 3 of 10
4.
Operation of safety valves
Safety valves that serve as important elements of the devices and pressure systems require particularly careful
and competent service. Any operational gasp may cause damage to the valve mechanism, and consequently
lead to the total failure of the pressure system. Therefore, during the operation, pay special attention to:
Proper setting of safety valve, suitable for the operating parameters of the equipment being protected.
Proper protection of the valve mechanism against arbitrary regulation and the possibility of damage.
Periodically verification of correct operation of the valve, in accordance with the requirements of
surveillance.
Proper maintenance and repair management.
Checking the safety valve operation involves lifting of the disc with a lever (pos. 10). Starting the lever causes
loosening of the spring force thereby allowing the minimum lift of the disc and the flow of medium. Release of
the lever should be made at a pressure between 75% and 85% of set pressure. Keep in mind that too frequent
checking may result in damage to the sealing surfaces of the valve disc and seat and thus to a loss of tightness,
and the complete lack of checking usually leads to “seizing" of the valve mechanism, what can have serious
consequences.
Drawing 1. Figure 781
Pos.
Number
Element
Material
1
2
3
4
5
6
7
8
9
10
Body
2)
Nozzle
Disc
Bell
Spindle
1)
Spring
Adjusting Screw
Locking Screw
Screw plug
Lifting lever
CuZn39Pb2
X39CrMo17-1
X39CrMo17-1
CuZn40Pb2
X20Cr13
B1
CuZN40PB2
CuZn40Pb2
CuZn40Pb2
-
1)
for the marine design (WM) spindle is made of the X17CrNi16-2
2)
with nickel coating
Drawing 2. Figure 776
Pos.
Number
Element
Material
1
2
3
4
5
6
7
8
9
10
Body
Nozzle
Disc
Lifing ring
Spindle
Spring
Adjusting screw
Locking screw
Screw plug
Lifting device
EN-GJMW-400-5
X39CrMo17-1
X39CrMo17-1
X3CrTi17
X20Cr13
BI
X20Cr13
X20Cr13
S235JR
-
