Tunnels Ventilation System

Product Types:

Axial fan

The axial fans manufacturing by this company is used for tunnels, power plants, ships, oil and gas and etc. the main features of this fans are as follows:
  • Fan inlet diameter from 40 cm to 4 m
  • Casing thickness from 4 to 16 mm
  • Capacity up to 2,000,000 m3/h
  • Pressure up to 7000 Pa
  • Fire rating up to 700 C and 90 min according to EN12101-3 standard
  • Blade material : corrosion-resistant cast aluminum, steel and various alloys of them
  • Anti-Stall fans to deal with the stresses caused by the difference in pressure and generated flow

Traditional Jet Fan

Jet fan

• Fan inlet diameter from 40 cm to 1.8 m
• Casing thickness from 4 to 10 mm
• Capacity up to 320,000 m3/h
• Thrust up to 2800 N
• Fire rating up to 700 C and 90 min according to EN12101-3 standard (or 2 h @ temperature of 400 C)
• Blade material : aluminum, steel and various alloys of them

Special Design – Banana Jet Fan

Witt and Sohn has exclusively developed a new patented of jet fan that named Banana jet fan. This type of jet fan has the following advantages compared to traditional design are:
  • Generates 20-50% more effective thrust than a traditional jet fan (at this design the outlet airflow is no contact to ceiling of tunnel and it would be prevent the turbulence and velocity loss in outlet air flow)
  • Reduction on the required quantity of jet fans
  • Lower power consumption
  • Lower space occupation and civil construction
  • Lower operating cost
  • Less turbulence of smoke layer at the ceiling


  • The blades are attaching to hub in method of Christmas tree. Using this method can be increased the resistance of blades against severe stress and prevent the piston effect and fire.
  • The air flow in reverse operation is 95 percent of direct flow because of fully symmetrical blades design.
  • Fire test certification according to EN 12101-3: 2015 approved by company MPA
  • High efficiency due to optimum design of the blades, hub, casing and motor connection type
  • Stall Free fan curve
  • Ability to use in the test bed for wind tunnel (to test the aerodynamics) with power up to 2 MW
  • Ability to use Unidirectional and Reversible
  • less electric energy require due to high efficiency (reducing the overall costs such as cost of cable, electricity, maintenance, control system)
Control and Monitoring Systems

Control and monitoring systems:

Witt & Sohn company to assist the operator to estimate fan repair time and performance monitoring use the FAG systems. This system is using the special sensors (such as temperature, vibration and rotation speed) to provide the following information:
1- Analyze the receiving data and display them in charts
2- Analysis charts to estimate and detection in operation state
3- Keeping the information in memory for offline graph review and analysis