8D Pneumatic
Electro-mechanical pneumatic pressure switch
info@nortrade.ro | +40 31 425 17 06/07
info@nortrade.ro | +40 31 425 17 06/07
Electromechanical pressure switches monitor system pressure and trigger an electrical contact at a defined set point — the simplest, most reliable way to convert a pressure threshold into a digital signal. Norgren offers three industrial product families: the 8D for basic pressure monitoring (5-250 bar hydraulic, 0.1-30 bar pneumatic), the 18D with high switching cycle count for cyclic processes (-1 to 30 bar pneumatic, 5-420 bar hydraulic, plus ATEX zone 2/22 versions for explosive atmospheres), and the 20D for aggressive and non-inflammable fluids with stainless-steel sensor (-1 to 100 bar all-fluid, with ATEX Ex db eb IIC T6 Gb variant for zones 1/2). Contacts are gold-plated on the 18D and 20D and silver-plated on the 8D; vibration resistance reaches 15 g on the 18D; protection is IP65/IP66 (IP64 on the 8D); UL/CSA approval applies to the 18D.
Electro-mechanical pneumatic pressure switch
Electro-mechanical hydraulic pressure switch
Electro-mechanical pneumatic pressure switch
Electro-mechanical hydraulic pressure switch
Electro-mechanical pneumatic pressure switch (ATEX certified)
Electro-mechanical all-fluid pressure switch
Electro-mechanical all-fluid pressure switch (ATEX certified)
Electro-mechanical low-pressure switch
On adjustable-hysteresis units (18D, 20D), the set point is configured via the adjustment screw under the cover — turn while observing a calibrated reference gauge. On fixed-hysteresis units (8D), the trigger point is factory-set per the specific part number — check the datasheet table. Always set with the system at the actual operating temperature, since cold-system bench setting can drift several percent at full operating temperature.
Norgren electromechanical pressure switches use a DIN EN 175301-803 form A connector (DIN 43650) or M12x1 — wire colours and pin assignments are printed on the connector body and on page 2 of every datasheet. The microswitch is a Single-Pole Double-Throw (SPDT) contact: terminal 1 is common, terminal 3 is normally-open (1-3 close on rising pressure) and terminal 2 is normally-closed (1-2 open on rising pressure). On the M12 version terminal 4 is the normally-open contact (1-4 close on rising pressure). Use the gold-plated contact variant for any signal under 24 VDC / 100 mA — silver contacts can develop a tarnish layer under low-current dry switching.
Pneumatic (compressed air, neutral gases): 8D Pneumatic (0.1-30 bar) or 18D Pneumatic (-1 to 30 bar). Hydraulic (oil, self-lubricating liquids): 8D Hydraulic (5-250 bar) or 18D Hydraulic (5-420 bar). All-fluid / aggressive media: 20D series (stainless-steel wetted parts). Don't use a pneumatic-rated switch with hydraulic oil — the diaphragm and seals will fail prematurely.
If your installation is in an explosive atmosphere zone (gas zones 0/1/2 per ATEX 2014/34/EU, dust zones 20/21/22), yes. Norgren offers 18D ATEX for zone 2 (gases) and zone 22 (dusts), and 20D ATEX for zones 1, 2, 21, 22. Outside ATEX zones, the standard 18D / 20D / 8D versions are sufficient — they're already intrinsically safe for general industrial use.
The 18D is rated for 10⁷ (10 million) mechanical switching cycles at full load — at 1 cycle per minute that's about 19 years of continuous operation. Real-world life depends on switching current (high inductive loads erode contacts faster) and ambient cleanliness. Gold-plated contacts last significantly longer than silver in dry-switching low-current PLC inputs.
