Type B/240
5
Figure 5.
B/240 Series Operational Schematic
OPEraTION
The movements of the diaphragm (D) are transmitted to the valve disc (O) by the stem (S) and the lever (L).
The downstream pressure through the pulse pipe (I) exerts a force under diaphragm (D) and this force is counteracted by the
adjusting spring (M).
The gas pressure on the diaphragm tends to close the valve disc; the antagonist action of the adjustment spring tends to open
it. under normal conditions the balance between these antagonist actions positions the valve disc in such a way as to ensure a
constant pressure and therefore the downstream capacity.
upon any capacity variation tending to cause an increase or decrease of pressure in relation to the pre-set pressure, the moving
unit reacts and finds a new balance, so re-establishing the pressure.
upon request the regulator is also provided with safety valve (VS) incorporated in the diaphragm (D); the adjustment at the pre-set
value is performed by means of spring (M1).
For the operation of the OS/66 slam-shut controller see the Instruction Manual 0048EN-OS66-IM.
M
OS/66
VS
D
O
S
L
I
M1
C
N
I
A
R
N
I
IC
F
F
O
A
T
R
A
T
A
I
ECC
M
AN I
A
N
G
O
L
O
Y
B
L
A
T
I
