Control Valves

DFT®‘s control valve offers a straight-thru design with a non obstructed flow with no abrupt changes in the flow path. See our highlighted features:

  • High Rangeability – Up to 200 to 1 Turndown Ratio
  • Unique “Internal” Design for a Control Valve
  • High flow Capacity
  • In-Line Repair
  • Class V Shutoff
  • Linear Flow Characteristic
  • ANSI 150 to 4500
  • Materials: Carbon Steel, Alloys, Stainless and Others
  • Low Cost of Ownership – Interchangeability
  • Liquids, gases, vapors, slurries and abrasive materials
  • Actuation: Manual, Pneumatic, Electric and Hydraulic
  • Accessories: Air Sets, Limit Switches, Manual Over-Ride, Positioners, etc.
  • Watch Our Control Valve Video
  • Receive Monthly Control Valve Tips to Your Inbox
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Unique Design

Closed Position

In the closed position, pressure moves the ball into the conical seating surface and holds it in place. Line contact between the ball and the seat results in high surface loads between the seat and the ball producing tight closure. As pressure increases, the seat load increases improving the seal. During each valve stroke, the ball rotates and repositions itself presenting a new sealing surface to the seat, prolonging the tight shutoff capability. Temperature changes do not affect the tight shutoff since there is freedom of movement between the ball and the seat. The ball cannot become wedged into the seat. The guide pin is used to set the valve position. During normal operation, it has no function.

Full Open Position

In the full open position a Straight-thru flowpath exists and the valve operates with the inherently high flow capacity of a venturi. The ball is firmly held out of the flow stream by four inclined pads on the cage which oppose the pressure differential force. The Bernoulli pressure differential moves the suspended particles towards the center of the fluid stream, preventing them from settling out into the body. This keeps the valve clean and free of material deposits in all positions during the valve stroke.

Close Throttling Position

As the valve opens, it operates in the close throttling position. In this position, the ball is supported by the two forward inclined pads on the cage and the seat surface which oppose the pressure differential force caused by the Bernoulli effect. The ball is supported and stable throughout the valve stroke and does not pinwheel or chatter.

Intermediate Throttling Position

In the intermediate throttling position, the ball rests on the four cage pads and is opposed by the same differential pressure force. The stable suspension of the ball throughout the valve stroke permits extremely close and repeatable control throughout the entire valve stroke.

Trim Type   Description Service Leakage Trim Characteristic
LSV-100™ Top Guided Trim lsv 100 cutaway Top guided, unbalanced, single seat trim. This style trim is suitable for pressure drops up to 600 psi in a non-cavitating environment. Your most economic choice for standard control applications. Up to 6”
Standard
Class 150
Class 300
Class IV Fast Opening
Linear
Equal %
LSV-200™ Cage Guided Trim LSV 200 Cage guided balanced and unbalanced trim. This is the preferred trim style for modulating control when moderate flow rates exist. The balanced trim is used for sizes over 2” to reduce actuator force requirements. Up to 6”
Standard
Class 125/150
Class 250/300
Class IV,
Class VI
Optional
Linear
Equal %
MSV-100™ Venturi Ball Design msv-100 Our unique venturi ball design provides superior control, long life and low maintenance costs for moderate pressure drop applications. The MSV-100 is designed for flanged applications. Seat replacement is accomplished on the bench. Up to 8”
Moderate
Class 600
Class 900
Class 1500
Class V Linear
Hi-100® Venturi Ball Design hit-100 This unique venturi ball design provides superior control, long life and low maintenance costs for severe pressure drop applications. The Hi-100 is designed for in-line repair using quick change trim. Up to 12”
Severe
All
Classes
Class V Linear

Our Control Valve Advantage

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