Stainless Steel, Pressure Switch, Alumunium, DNS Type, Hengesbach

Pressure sensors

All pressure sensors have measuring bellows, some made of copper alloy, but the majority of high-quality stainless steel. The measuring bellows are exposed to a minimal load and perform only a small lifting movement. This results in a long service lifetime with only little drift switching point and high overload safety. Furthermore, the elongation of the bellows is limited by an internal stop so that the forces resulting from the over pressure cannot have impact on the switching device. The parts of the sensor in contact with the medium are welded together without filler metals. The sensors contain no seals. Copper bellows, which are used only for low pressure ranges, are soldered to the sensor housing. The sensor housing and all parts of the sensor in contact with the medium can also be made entirely from stainless steel 1.4571 (DNS series). Pressure switch with stainless steel sensor system, optional with plastic-coated housing.

Pressure connection

The pressure connection on all pressure switches is designed in accordance with DIN 16288 (pressure gauge connection G 1/2A). If wanted, the connection can also be made with a G 1/4 internal thread according to ISO 228 Part 1. Maximum screw-in depth on the G 1/4 internal thread is 9 mm.


Pressure switches of the DNS series are suitable for monitoring and controlling pressures in chemical plants, process
engineering and any situation where the pressure of aggressive liquids and gases must be monitored. All components of the sensor system are made from high-quality stainless steel (1.4571) and welded using the latest methods without filler metals. The pressure sensor is hermetically encapsulated and contains no sealing materials.


Pressure connection: External thread G 1/2 (pressure gauge connection) according to DIN 16 288 or internal thread G 1/4 according to ISO 228 Part 1.

Switching device: Robust housing (200) made of seawater-resistant diecast aluminium GD Al Si 12.

Degree of protection:

  • IP 54, in vertical position.
  • IP 65, for EEx-d version.

Pressure sensor materials: Pressure bellows and all parts in contact with medium. X 6 Cr Ni Mo Ti 17122 Material no. 1.4571

Mounting position: Vertically upright or horizontal.

Max. ambient temperature at switching device:

  • –25…+70 °C.
  • For EExd versions: –15…+60 °C.

Max. medium temperature: The maximum medium temperature at the pressure sensor should not exceed the ambient temperature permitted at the switching device. Temperatures may reach 85°C for short periods (not EEx-d). Higher medium temperatures are possible provided the above limit values for the switching device are ensured by suitable measures (e.g. siphon).

Mounting: Directly on the pressure line (pressure gauge connection)or on a flat surface with two 4 mm Ø screws.

Switching pressure: Adjustable from outside with screwdriver.

Contact arrangement: Single-pole changeover switch.

Plastic coating: The diecast aluminium housing in GD Al Si is chromated or stove-enamelled with resistant plastic. Corrosion tests with 3% saline solution and 30 temperature changes from +10 to +80°C showed no surface changes after 20 days.

Download Data Sheet: Pressure Switches Type DNS