The Valve operates on the discharge side of the
pump. As the flow through the pipeline starts or stops,
the ball automatically rises or falls, opening or closing
the valve. The handwheel is there to lock the ball in
position. The handwheel can be used to isolate, but with back pressure. The Dual valve can work in the horizontal and vertical position.

The Dual Valve is the only proven maintenance and
trouble-free slurry valve in the world with all these
features

• Rotating and floating ball which self-adjusts to flow.
• Self-cleaning, due to the freely rotating ball.
• Long ball life, due to ball rotation.
• Replaces two valves: check valve and either a gate, knife gate, pinch or diaphragm valve.
• Full port opening - no obstruction to the flow.
• Virtually no pressure drop which eliminates water
  hammer.
• Long seat life - seats are out of the flow and can be rotated in-line to increase seat life fourfold.
• Easy maintenance - seat and ball can be inspected or replaced without removing the Dual Valve from the pipeline.

• Indicator to show valve in open or closed position.
• Virtually maintenance free because of the simple design.
• Simple manual operation - manual handwheels is standard and automatic actuators are not required (but can be fitted).

• Valve housing is constructed of high quality carbon
  steel. Stainless steel is an option.
• Valve housing can be natural rubber lined. A range of
  elastomer grades is available for corrosive
  duties (URETHANE, Ceramic, etc.)
• Ball is made of hollow carbon steel and is urethane
  coated. Other elastomers are also available.
  (Stainless Steel for High Pressure)
• The seat is made in special Abrasion Resistant AR Steel (500 Brinnell hardness), URETHANE or Stainless Steel
  and is replaceable.
• Flanges are typically made in carbon or stainless
  steel and drilled to customer requirements. For
  Europe, flanges are made to DIN.
• The ball locking spindle mechanism is made in
  stainless steel as standard.
• Working pressure standards are: 16, 25, 40, 60,
  80 and 100 bar
• Operating temperatures to 80°C. Higher conditions
  are possible if the valve is constructed from suitable
  material.