Mechanical pressure switches
41
Liquids and gases
DNS/VNS
Pressure switches and vacuum switches with stainless steel
sensors (1.4571)
Pressure switches of the DNS series are suitable All components of the sensor system
for monitoring and controlling pressures in are made of high-quality stainless steel (1.4571)
chemical plants, process engineering and and welded using the latest methods without
any situation where the pressure of aggressive filler metals. The pressure sensor
liquids and gases must be monitored. is gasket-free plasma-welded.
SIL 2 according IEC 61508-2
DNS3-201
Technical data Product Summary
Pressure connection
Type Setting range Switching Max. Dimen-
External thread G 1/2 (pressure gauge
connection) according to DIN 16 288 and
differential permissible sioned
internal thread G 1/4 according to
(mean values) pressure drawing
ISO 228 Part 1.
Switching device
Switching differential not adjustable page 25 + 26
Robust housing (200) made of seawater-
VNS301-201 -250+100 mbar 45 mbar 3 bar
resistant diecast aluminium GD Al Si 12.
VNS111-201 -1*+0.1 bar 50 mbar 6 bar
Protection class
DNS025-201 0.040.25 bar 30 mbar 6 bar 1 + 15
IP 54, in vertical position.
DNS06-201 0.10.6 bar 40 mbar 6 bar
Pressure sensor materials
DNS1-201 0.21.6 bar 60 mbar 6 bar
Pressure bellows and all parts in contact with
medium. X 6 Cr Ni Mo Ti 17122 Material no.
DNS3-201 0.22.5 bar 0.1 bar 16 bar
1.4571
DNS6-201 0.56 bar 0.15 bar 16 bar 1 + 18
Mounting position
DNS10-201 110 bar 0.3 bar 16 bar
Vertically upright and horizontal.
DNS16-201 316 bar 0.5 bar 25 bar 1 + 16
Max. ambient temperature at switching
device
Switching differential adjustable
25+70 C.
VNS301203 250+100 mbar 70 300 mbar 3 bar
Max. medium temperature
VNS111203 1*+0.1 bar 90 550 mbar 6 bar
The maximum medium temperature at the
pressure sensor must not exceed the permitted DNS025203 0.040.25 bar 60 300 mbar 6 bar 1 + 15
ambient temperature at the switching device.
DNS06203 0.10.6 bar 80 400 mbar 6 bar
Temperatures may reach 85C for short
DNS1203 0.21.6 bar 100 600 mbar 6 bar
periods.
Higher medium temperatures are possible
DNS3203 0.22.5 bar 0.15 1.5 bar 16 bar
1 + 18
provided the above limit values for the
DNS6203 0.56 bar 0.25 2.0 bar 16 bar
switching device are ensured by suitable
DNS10203 110 bar 0.45 2.5 bar 16 bar
measures (e.g. siphon).
1 + 16
DNS16203 316 bar 0.8 3.5 bar 25 bar
Mounting
Directly on the pressure line (pressure
gaugec onnection) or on a flat surface with two
4 mm screws.
* At very high vacuums, close to the theoretical maximum of 1 bar, the switch may not be usable in
Switching pressure
view of the special conditions of vacuum engineering. However, the pressure switch itself will not be
Adjustable from outside with screwdriver.
damaged at maximum vacuum.
Switching differential
For values see Product Summary.
Calibration
Contact arrangement
The DNS and VNS series are calibrated for falling pressure. This means that the adjustable switching
Single-pole changeover switch.
pressure on the scale corresponds to the switching point at falling pressure. The reset point is higher
by the amount of the switching differential. (See also page 27, 1. Calibration at lower switching point).
Switching 250 VAC 250 VDC 24 VDC
capacity (ohm) (ind) (ohm) (ohm)
Normal 8 A 5 A 0.3 A 8 A
Plastic coating
The diecast aluminium housing in GD Al Si is
chromated and stove-enamelled with resistant
plastic. Corrosion tests with 3% saline solution
and 30 temperature changes from +10 to
+80C showed no surface changes after 20
days.
-DNS/VNS
see page 66
Protection Class:
s IP 54
Accessories Solenoid valves Flow monitors Temperature sensors Thermostats Pressure transmitters Pressure switchesMechanical pressure switches
42
Liquids and gases
DNS/VNS
Pressure and vacuum switches with stainless steel sensors
(1.4571)
Chemical version (switching housing with liquids and gases must be monitored. All
surface protection) components of the sensor system are made
Pressure switches of the DNS series are from high-quality stainless steel (1.4571) and
suitable for monitoring and controlling pressures welded using the latest methods without filler
DNS6-351 in chemical plants, process engineering and any metals. The pressure sensor is gasket free
situation where the pressure of aggressive plasma welded.
SIL 2 according IEC 61508-2
Technical data
Pressure connection External thread G 1/2"
Type Setting range Switching Max. Dimen-
(pressure gauge
connection) according
differential permissible sioned
to DIN 16 288 and
(mean value) pressure drawing
internal thread G 1/4"
according to ISO 228
Part 1
Hysteresis not adjustable page 25 + 26
Switching device Robust housing (300)
VNS301-351 -250+100 mbar 45 mbar 3 bar
made of seawater-
resistant diecast VNS111-351 -1*+0,1 bar 50 mbar 6 bar
aluminium GD Al Si 12
DNS025-351 0,040,25 bar 30 mbar 6 bar 2 + 15
Protection class IP 65, in vertical position
DNS06-351 0,10,6 bar 40 mbar 6 bar
Pressure sensor Pressure bellows and
materials all parts in contact
DNS1-351 0,21,6 bar 60 mbar 6 bar
with medium
DNS3-351 0,22,5 bar 0,1 bar 16 bar
X 6 Cr Ni Mo Ti 17122
2 + 18
DNS6-351 0,56 bar 0,15 bar 16 bar
Material no. 1.4571
Mounting position Vertically upright and
DNS10-351 110 bar 0,3 bar 16 bar
2 + 16
horizontal
DNS16-351 316 bar 0,5 bar 25 bar
Max. ambient
temperature
at switching device 25 to +70 C
Max. medium The maximum medium * At very high vacuums, close to the theoretical maximum of 1 bar, the switch may not be usable in
temperature temperature at the
view of the special conditions of vacuum engineering. However, the pressure switch itself will not be
pressure sensor must
damaged at maximum vacuum.
not exceed the permitted
ambient temperature
at the switching device.
Calibration
Temperatures may reach
The DNS and VNS series are calibrated for falling pressure. This means that the adjustable switching
85 C for short periods.
Higher medium
pressure on the scale corresponds to the switching point at falling pressure. The reset point is higher by
temperatures are
the amount of the switching differential. (See also page 27, 1. Calibration at lower switching point).
possible provided
the upper limit at
the switching device
is ensured by suitable
measures (e.g. siphon).
Plastic coating The diecast aluminium
housing in GD Al Si
is chromated and
stove-enamelled with
resistant plastic.
Corrosion tests with 3%
saline solution and 30
temperature changes
from +10 to +80C
showed no surface
changes after 20 days
Contact arrangement Single-pole changeover
switch
Switching 250 VAC 250 VDC 24 VDC
capacity (ohm) (ind) (ohm) (ohm)
Normal 8 A 5 A 0.3 A 8 A
DNS/VNS
see page 66
Protection Class:
s IP 65