Design And Principle Of Operation - Samson 44-7 Mounting And Operating Instructions

Design and principle of operation

3 Design and principle of oper-
ation
Î Refer to Fig. 3
The regulator are closed when relieved of
pressure. They open when the upstream
pressure rises above the adjusted set point.
The Type 44-4, Type 44-7 and Type 44-8
Excess Pressure Valves mainly consist of the
valve (1) with seat (2) and plug (3) as well
as the actuator with operating diaphragm
(6.1), set point spring (8) and set point ad-
juster (10).
The excess pressure valve is used to maintain
the pressure upstream of the regulator to an
adjusted set point.
The process medium flows through the regu-
lator between seat and plug in the direction
indicated by the arrow on the body. The po-
sition of the valve plug determines the flow
rate and, as a result, the upstream pressure.
The upstream pressure p
transmitted over the control line (11) to the
operating diaphragm (6.1) where it is con-
verted into a positioning force. This force is
used to move the valve plug according to the
force of the set point spring (8). The spring
force can be adjusted at the set point adjust-
er (10).
The Type 44-8 Safety Excess Pressure Valve
additionally has a second backup dia-
phragm (6.2). Upon failure of the first oper-
ating diaphragm (6.1) the regulator contin-
ues to function using the backup dia-
phragm (6.2). In this case, the regulator
functions as a safety valve when the up-
stream pressure rises too far and opens the
12
to be controlled is
1
valve. Diaphragm failure is indicated by a
red mark in the diaphragm rupture indicator
(12) (point of response at approx. 1.5 bar)
or medium escapes at the test connection.
The Type 44-4 Safety Excess Pressure Valve
additionally has a second backup dia-
phragm (6.2). Upon failure of the first oper-
ating diaphragm (6.1) the regulator is fully
opened. Diaphragm failure is indicated by a
red mark in the diaphragm rupture indicator
(12) (point of response at approx. 1.5 bar)
or medium escapes at the test connection.
1 Valve body
1.1 Stopper
1.2 Seal
1.3 Seal
2 Seat
3 Plug with plug seal
3.1 Balancing piston
3.2 Plug nut
3.3 Plug stem
3.4 Plug spring
3.5 Plug nipple
3.6 Guide nipple
4 Coupling nut
5 Inspection bore
6 Actuator housing
6.1 Operating diaphragm
6.2 Backup diaphragm
7 Diaphragm stem
8 Set point spring(s)
9 Spring plate
10 Set point adjuster
11 Control line
12 Diaphragm rupture indicator
13 Body screws
14 Distance ring
15 Diaphragm plate nut
16 Diaphragm plate
17 O-rings
EB 2723 EN