The IVR model Butterfly dampers, offered by Intervalve are essentially seatless Butterfly valves intended for low pressure gas lines and air lines. The lightweight construction with the narrow wafer body enables easy fitment of these valves in ducts, manifolds and exhaust lines without additional support or strengthening of pipe lines.

IVR valves are primarily intended for low-pressure large volume gas / air flow control applications. The absence of seat substantially reduces the valve operating torque requirements and makes the valve very effective for flow control / regulation duties. IVR is an ideal choice for furnace air flow and combustion control applications.

Even though the body is designed for a maximum pressure of 2.5 bar the maximum shut off pressure is limited to 0.5 bar only. The disc flap is held in position by a stub shaft with an axial locking arrangement provided on the top shaft. The top shaft sealing is through stuffing box type gland sealing arrangement, which is field adjustable.

Actuator mounting bracket
Valve Inspection & Testing
Flange standard

Leakage Rate



ISO 5211
API 598/ FCI : 70-2 (Class I)
ASME Class 150, DIN EN 1092-PN 6 / PN 10, BS 10 Table D
Less than 1% of Cv Value



Construction & Type :

Centric Disc, Seatless Butterfly damper

2. Body type : Narrow wafer single piece
3. End connection : Wafer, sandwiched between flanges
4. Size range : DN 40 to DN 1200
5. Maximum operating pressure : 0.5 bar (max)
6. Operating temperature range : -250 C to 6000 C (depending on MOC)
7. Operation : Manual or actuated with Pneumatic / Electric actuator
8. Standard Material of Construction (MOC)    
  Valve Body : WCB / CF8 / CF8M
  Disc : CS-IS2062 / SS304 / SS316 (WCB / CF8 / CF8M
(Sizes upto DN 200)
  Deive end & non drive end shaft : SS410 / SS316SH / 17.4 PH


  • Lightweight design suitable for mounting in ducts, exhaust lines and ventilation pipes.
  • Very low operating torque due to seatless construction.
  • Ideal for flow control / modulating duties in low pressure gas lines.
  • Very low pressure drop in open condition.
  • Wide operating temperature range to cater to exhaust & flue gas control lines.
  • Zero external leak due to the stuffing box type gland sealing arrangement.
  • Perfect adaptability for manual or actuated applications.

Specifications & dimensions are subject to change without prior notice