Stafsjö D2G Instrucciones De Instalación Y Servicio página 6

B3 Pressure, flow direction, valve position and flushing
When the knife gate valve is open, P1=P2, the pipe line pressure may not exceed maximum
allowable working pressure body according to each valve. When the valve is closed, the
differential pressure ∆P, is the difference between P1 and P2 (∆P = ± (P1-P2).
The differential pressure ∆P may not exceed maximum allowable differential pressure
according to each valve. Maximum allowable differential pressure for closed valve is
available in data sheets.
• Valves types XV, HL, HG, HP, HX, WB, D2G, SLV, SLF, SLH and SLX are bi-directional and can therefore be installed
independent of the pressure ratio in any direction in the pipe line.
• Valid for MV only:
This valve type has different differential pressure ∆P capacities in the flow directions. The maximum ∆P capacity of
the valve is achieved when the SEAT SIDE is installed as the valve outlet (towards P2) provided that P1 > P2. When
the valve is closed, the pressure ratio shall be P1>P2. Some sizes of MV equipped with specific seats are capable to
handle certain differential pressure in reversed pressure direction. For further information, see data sheets on
www.stafsjo.com.
• Valid for JTV, RKO and RKS only: These valve types have different differential pressure ∆P capacities in the flow
direction. The maximum ∆P capacity of the valve is achieved when the seat side is installed as the valve inlet
(towards P1) provided that P1>P2. When the valve is closed, the pressure ratio shall be P1>P2.
• Valid for TV only:
This valve shall be installed with the seat side to the tank. The removable retainer ring shall be mounted towards
the tank which implies that changing of the seat can only be done when the tank is empty.
• All valve types, except for valves D2G, JTV, RKO and RKS are preferred to be installed in a horizontal pipe (system)
with the actuator in a vertical upright position.
Valid for D2G, RKO, JTV and RKS only:
These valve types are designed to be installed in a vertical pipe.
• Valves installed in inclined position are mainly affected by type of media, flow rate and sedimentation in the
process. To estimate the effect of such is the responsibility of the customer. Stafsjö will assist on request.
• A valve can be equipped with flushing to improve function depending on type. When so is the case, customer has
too secure that flushing port will not be clogged. Preferably by use of check valve mounted directly on valve port.
Stafsjö can assist on request.
B4 Necessary support for special cases
The dead weight of a valve in large dimension together with its actuator or a small valve with heavy actuator, may
cause tensions/deformations in the valve that could affect the valve's function, specifically when it is installed at
inclined positions or in a vertical pipe. In these cases, the valve and/or actuator shall be supported to avoid functional
failure.
Valves that are exposed to vibrations or other mechanical stresses can be subject to forces that will affect valves
tightness and ability to operate. In these cases, the valves and actuators shall be supported to avoid function failure.
Support details are the responsibility of the customer. Stafsjö will assist on request.
Fig. 3
Seat side
Seat side
RKO, RKS,
MV
JTV, TV
P1 P2
Document: is-VALVE, 21-02-11 issue: 15