1
Design and principle of
operation
The regulators consist of a valve with a bal-
anced plug and a closing actuator with an
operating diaphragm.
Types 45-1 and 45-3 have a fixed set point
determined by the set point spring inte-
grated in the valve body, whereas
Types 45-2 and 45-4 allow the set point to
be adjusted by the set point springs attached
to the actuator.
The regulators are designed to maintain the
differential pressure between the high-pres-
sure and low-pressure pipes at the adjusted
set point. The valve closes when the differen-
tial pressure rises.
On
Types 45-1 and 45-2
installed in a flow
pipe, the medium flows through the valve in
the direction indicated by the arrow. The
high pressure in the valve outlet is transmit-
ted through the attached control line (11) to
the high-pressure side of the operating dia-
phragm. The low pressure from the return
pipe is transmitted to the low-pressure side
of the diaphragm via the control line (12)
which must be routed externally on site.
On Types 45-3 and 45-4 installed in a re-
turn pipe, the low pressure upstream of the
valve is directed over an internal hole (13)
to the low-pressure side of the diaphragm.
The high pressure from the flow pipe is
transmitted to the high-pressure side of the
diaphragm through the control line (11)
which must be routed externally on site.
The differential pressure acting on the oper-
ating diaphragm generates a positioning
force, which positions the plug against the
force of the set point springs (8, 10).
2
Installation
2.1
Mounting position
Install the differential pressure regulator in a
horizontal pipeline with the actuator verti-
cally suspended. Regulators in nominal sizes
DN 15 to 25 may also be installed in verti-
cal pipelines.
For medium temperatures above 80 °C,
note that the regulator must not be installed
with the diaphragm actuator pointing up-
ward.
Make sure that the medium flows through
the valve in the direction indicated by the
arrow on the valve body.
2.2
Control line
Adapt a control line with a 6 mm pipe di-
ameter to the installation conditions on site.
Then attach it to the valve and to the pipe-
line according to the applicable installation
schematics (Fig. 1), making sure the control
line is free of any dirt.
2.3
Strainer
Install a strainer (e.g. SAMSON Type 1 NI)
upstream of the regulator to prevent sealing
particles, weld spatter, pipe scale, and other
impurities carried along by the process me-
dium from impairing the proper operation,
especially the tight shut-off of the regulator.
Make sure that the medium flow corre-
sponds with the direction indicated by the
arrow on the strainer body. Install the
strainer with the filter element vertically sus-
pended. Ensure that ample space is avail-
able to remove the filter.
4
EB 3124 EN
Design and principle of operation
