Design And Principle Of Operation - Samson 2417 Series Mounting And Operating Instructions

Design and principle of operation

3 Design and principle of oper-
ation
Î Refer to Fig. 3
The Type 41-73 Excess Pressure Valve con-
sists of a Type 2417 Opening Valve and a
Type 2413 Actuator. The valve and actuator
are delivered separately and must be assem-
bled according to the instructions in sec-
tion 6.1.1.
The excess pressure valve is used to maintain
the pressure upstream of the valve to an ad-
justed set point.
The process medium flows through the valve
between seat (2) and plug (3) in the direc-
tion indicated by the arrow on the body. The
position of the valve plug determines the
flow rate and, as a result, the pressure ratio
across the valve. The plug stem is sealed by
a frictionless bellows (5.1). The upstream
pressure p is transmitted over the compen-
1
sation chamber (18) and control line (17) to
the operating diaphragm (12) (operating
bellows (12.1) in the version with bellows
actuator) where it is converted into a posi-
tioning force. This force is used to move the
valve plug depending on the force of the set
point springs (7). The spring force is adjust-
able at the set point adjuster (6). The valves
with K 4 and higher have a balancing bel-
VS
lows (4). The upstream pressure acts on the
outside of the bellows and the downstream
pressure on the inside of the bellows. As a
result, the forces produced by the upstream
and downstream pressures acting on the
plug are balanced out.
14
The valve closes when the downstream pres-
sure rises.
1 Valve body
2 Seat
3 Plug
4 Balancing bellows
5 Plug stem
5.1 Bellows
6 Set point adjuster
7 Set point springs
7.1 Spring plate
7.2 Nut
7.3 Cap screw
7.4 Needle bearing and axial disk
8 Crossbeam
Stud bolt
8.1
(view drawn turned by 90°)
8.2 Nuts for stud bolts
8.3 Tapped holes
9 Fastening nuts
10 Diaphragm actuator/bellows actuator
11 Actuator stem
12 Operating diaphragm
12.1 Operating bellows
13 Diaphragm plate
14 Diaphragm plate nut
15 Nuts and bolts
Control line connection G ¼
16 (with screw joint with restriction when used
with steam)
Control line (to be provided on site)
17
(available as control line kit for direct
pressure tapping at the body u T 2595)
18 Compensation chamber
19 Filler plug
EB 2517 EN