Internal Dart Valves

iDart with flexible coupling

DART’s internal dart valves are bodiless valves suitable for installation within the slurry tank, cell or box. There are two main variations – self-contained triDart valves which are factory calibrated and installed as a single unit; and iDart valves which have a bolt down seat cage with only a shaft extending to the actuation unit. Both types offer the stability and reliability advantages of head-guiding where the plug is guided into the seat with bars set out all around the plug.

Do you have these issues?

  • Poor level control or Spillage
  • Bending or breaking of shafts
  • Excessive wear
  • Misalignment of valve and actuator shaft
  • Bouncing or vibration of valves, poor coupling.
  • Maintenance problems

Then eDART internal valves will benefit you.

 

 

Product Variations

The TriDart is a self-contained internal dart valve which is dropped into the vessel and bolted down. It has the distinct advantage of being pre-assembled and calibrated prior to shipment to site. The TriDart is recommended for tank depth of up to 2–3 metres.
iDart with flexible coupling
The valve needs the simple steps of bolting down the actuator mounting plate to the framework and the seat cage to the vessel; then the positioner needs to be calibrated. The valve does not require additional internal guide plates as the guiding is done on the plug head.
The sealed TriDart has bellows, in the same arrangement as the single and dual external dart valves, so the valve can be used in a pressurised vessel such as the underflow of a cyclone.
eDART Pedestal and Actuator
eDART specializes in the design, development, manufacture and ongoing support in the field of valves for the flow control of slurry applications. Broadly speaking, dart valves give the highest level of satisfaction and form the core of the eDART offering. eDART offers three main categories of dart valves – external, internal and inline. There are a number of sub-categories for each type: various outlet orientations for the external dart valves and linings and internal configurations for the internal dart valves (including three port dosing valves). eDART offers four types (sub-categories) of internal valves, as shown above. The iDart has been developed for deep tanks (more than two metres). The Tridart for shallower tanks (although deeper is possible when necessary) and it can be sealed with a bellows seal for pressurised applications (cyclones). All eDART products incorporate eDART’s technology:
head guided plugs
  • Flow through the seat introduces dynamic forces on the plug which is one source of vibration
  • Guides on the shaft cannot be accurately sized because the slurry enters gap and cause the valve to seize
  • Shaft guides are also too far from the seating surface to be effective
  • The answer is to head guide the plug directly into the seat with a cage
Flexible linkages
  • One cannot talk about the desirability of linear flow characteristics while there is backlash in the coupling between the valve and actuator
  • The flexilink couples the actuator stem to the valve shaft so that the backlash is eliminated
  • The Flexilink mechanism is based on a universal joint and thus accepts the inevitable angular misalignment between the valve shaft and actuator stem
  • The Flexilink mechanism protects the actuator guides and seals
External feedback
  • Engineered precisely to provide a linear response and to limit the hysteresis between the linear motion of the shaft and the rotary input the positioner’s encoder.
eDART offers the “pedestal for third party valves” as a product to the market because eDART has control over the effectiveness of the valve’s working. Control is meaningless if the coupling between the actuator and the valve is loose. With these factors in mind, eDART cannot supply “wetworks” without the eDART “topworks” as the performance of the valve will be jeopardised. This could be due to incorrect matching of items (actuator shaft to plug stem), incorrect actuator stroke lengths or diameter sizes and eDART will be responsible to ensure the valves work correctly.