ValkTwinRail | Ventilation mechanism

The ValkTwinRail ventilation system has a unique construction, with the pullpush tubes (for individual control of the two air vent sections) installed on top of each other on the truss. This allows the two sets of push rods (from the uppermost and lowermost pull-push tube, resp.) to move through each other, and the screen can sit freely against the truss.


The ValkTwinRail system consists of a hinge element with an exceptional form that keeps the push rods together in a steel grip. And it has a unique tube clip that, given its wide design, can absorb the tolerances of your greenhouse without difficulty and is absolutely free of torsion. The Valk-Plus push rods are customised exactly to your specifications in a completely automated production process. They undergo various unique processing steps to become distinctive in terms of functionality and ease of mounting.


Browse through the brochure for the ValkTwinRail system in Dutch, English, German or Chinese.

ValkTwinRail ventilation mechanism

Unique properties

  • Two push/pull tubes above each other
  • Set of push rods moves simultaneously on the upper and lower tube
  • Is combined with Valk-Plus vent push rods and StabiMax hinge element
  • The screen can sit freely against the truss
  • Screening on upper beam possible
  • Double consoles, to be secured with two bolts
  • Guaranteed ‘free-running' of the push rods
  • Calculation programme calculates the space required between the two sets of push rods

StabiMax hinge element

Unique properties

  • Keeps the Valk-Plus push rods together in a steel grip
  • Push rods are mounted in a twist-resistant manner
  • The tube clip absorbs tolerances of 2 x 6 mm
  • Prevents gear rack wear
  • Improved climate control
  • Extremely uniform ventilation gaps
  • Perfect seal when air vents are closed
  • Higher CO2 dose, better energy savings
  • Lower tube with expander or extension
  • Upper tube with long hinge


For the required stability, the ValkTwinRail uses the StabiMax hinge element and the Valk-Plus push rods. These two familiar innovations of Van der Valk Horti Systems are now being employed all over the world. The ValkTwinRail ventilation mechanism works optimally in combination with the ValkPlus push rod, which is customized to your specifications in an automated production process.

Calculation tool

The ValkTwinRail ventilation mechanism is calculated in detail for every situation using the unique calculation programme WinTop. In collaboration with TNO (the top independent research institution in the Netherlands), the WinTop calculation programme was developed. On the basis of several variables (the geometry of the covering, the maximum local wind load, the preferred opening angle, etc.), all factors are calculated that could affect the reliability of the system. This concerns factors like the required construction strength, free-running of the mechanism with regard to the covering construction, and position of the rail consoles and gear racks.

Still have any questions? Contact us

Download the brochure

"Thanks to the innovative character and high-quality products of Van der Valk Horti Systems, we can provide our customers with the best greenhouse horticulture even better."

Ammerlaan | Maurice kassenbouw

To all projects

Van der Valk Horti Systems

Zwartendijk 73
The Netherlands

Phone +31 (0)174 - 21 22 23
Fax +31 (0)174 - 24 27 27