Kobold SMN Displacer Flow Switch

Kobold SMN Displacer Flow Switch is used when extremely low flow switch points are required together with minimum pressure loss at high flow rates. The flow switch operates on the well-known float principle. An orifice float with its integral circular magnet moves within a cylindrical flow tube in the direction of flow and against a spring.

Kobold SMN Displacer Flow Switch

The magnetic field of the float activates a reed contact which is mounted on the outside of the instrument in a sliding protective casing. The special construction of the float and flow tube means that only a low flow is required to raise the float and hence activate the reed contact. If the flow rate increases further and the float reaches the top of its travel an additional flow path opens allowing high flow rates without a significant increase in the pressure loss.

Kobold SMN Applications

• Water cycles
• Heating installations
• High pressure purifiers
• Cooling circuits
• Sanitary technology
• Prevention of low water levels
• Pumps
• Confining fluid control

Application in hazardous areas

Mechanics
The apparatus can be used as follows in explosive atmospheres in accordance with the applicable erection regulations on machines, devices and plants, such as e.g. EN 1127-1, EN 60079-14, etc.:

• In Zone 1 (gas hazard, category 2G) in the explosion groups IIA, IIB, and IIC
• In Zone 2 (gas hazard, category 3G) in the explosion groups IIA, IIB, and IIC
• In Zone 21 (dust hazard, category 2D) in the explosion groups IIIA andCIIIB
• In Zone 22 (dust hazard, category 3D) in the explosion groups IIIA and IIIB

ATEX N/O contact type 41R57 ...G0:
II 3 G Ex ic IIC T4 Gc
II 3 D Ex ic IIIC T125°C Dc
-20°C ≤Ta ≤80°C
max. 250 VAC/DC/1,5 A/100 W/100 VA

Kobold SMN Technical Details

• Housing:
  SMN-11...: brass, Ms 58
  SMN-12...: stainless steel, 1.4301
• Float:
  SMN-11...: brass, Ms 58
  SMN-12...: stainless steel, 1.4301
• Pin:
  SMN-11...: brass, Ms 58
  SMN-12...: stainless steel, 1.4301
• Spring: stainless steel
• Magnets: ceramic
• Max. temperature: 100°C
• Max. pressure:
  SMN-11...: 250 bar
  SMN-12...: 350 bar
• Installation position: horizontal or vertical (upward direction), flow in direction of the arrow
• Contact components:
  1 bistable reed contact
  N/O contact, changeover contact
• Electrical connection: connector DIN EN 175301-803
• Switching range: 1 - 100 l/min water Switch point at approx .1 l/min falling
  Connection: G1 female thread
  Material: brass or stainless steel
  p_max: 250 bar (brass), 350 bar (stainless steel)
  t_max: 120°C
  Accuracy: ±5 % of full scale
  Reed contact

Download Datasheet: Kobold SMN Displacer Flow Switch

Reference : kobold.com