Contexa - Automation systems for liquids and powders
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The ultra-compact and accurate laboratory robot


Contexa SA has a large experience in volumetric and gravimetric dosing of liquids and powders. The COBRA is a volumetric dosing system for liquid raw materials. A scale validates the accuracy of the dosed weights.
A formula is prepared in a few minutes by the COBRA robot. The raw materials are stored in a cupboard or a storage area.
"Because the R&D department needs to evaluate the result of its creation in a very short time, we have designed an accurate and fast robot."

Main characteristics

  • Ideal for creation, sampling and production bases
  • Production of formulas from a few grams to 5 kg (11 lb) in less than 5 minutes
  • The materials can be dosed one after the other, simultaneously or in a combination mode
  • Dosing in 4 to 8 seconds per raw material with an accuracy of a few milligrams
  • Allows the automation of 200 raw materials with their storage on 2m2 (20 sq. ft)
  • Different sizes of syringes available to optimize your productivity

Volumetric Dosing working principle

  • The COBRA is equipped with a mobile table on which are affixed 200 dosing syringes
  • Each syringe is connected to a specific raw material
  • The weight to be dosed is automatically converted into a volume, i.e. in a mechanical movement of the COBRA's dosing table
  • The system is entirely mechanical
  • When the dosing table goes down, all the raw materials are pumped
  • The valve(s) matching the raw materials that need to be dosed is (are) opened on the dosing side
  • The others remain opened on the stock side (hence closed on the dosing side)
  • When the dosing table goes up, the product(s) to be dosed is (are) sent to the dosing head
  • The other chemicals go back to the storage
  • The raw materials can be dosed one after the other or at the same time or in a combination mode

Technical specifications


  • Materials in dynamic contact with the chemicals: Stainless steel, Glass, Kalrez or PTFE
  • L x D x H: 1'361 x 930 x 1'237 mm (53.6 x 36.6 x 48.7 in)
  • Weight: 500 kg (1'100 lb)
  • Necessary power for one COBRA and its peripherals: 3.7 kWh (16A /230V or 32A / 110V)


  • 200 stainless steel syringes per module, or glass for the sensitive chemicals
  • Available diameters:
     - Stainless steel: 10, 16, 20 and 25 mm (0.39, 0.63, 0.79 and 0.98 in)
     - Glass: 10, 16 and 20 mm (0.39, 0.63, 0.79 in)
  • Min / Max dosed weight per raw material: 20 mg / 441 g (0.97 lb)
  • Total pumping and dosing cycle: 2 x 30 sec

Dosing head

  • Diameter 66 mm (2.6 in) for small diameter syringes (400 ml beaker)
  • Diameter 98 mm (3.86 in) for big diameter syringes (800 ml beaker)


  • Lid system
  • ATEX zone II classifications (Class II, div 2)
COBRA, the world's most compact
liquids dosing system