Design / Bonded liner concept

With our manufacturing - casting and vulcanisation experience Alfa Valves has created a full line of concentric highly reliable and efficient butterfly valves. All our valve liners are vulcanised with a bonded liner to reduce maintenance and to give with a high flow performance.

The Alfa Valves bonded liner butterfly valves a traditional way of construction with many years of experience in a variety of applications a 100% tight shut-off between disc and liner on all sizes due to precision machining of internal parts (Disc, Bronze bearings bushes and Shaft) and transfer moulding vulcanisation process with prevision tooling.

Due to accurate and repeatable liner dimensions in combination with the precision machined internal parts this bonded liner valve is very reliable and provides constant low torque and tight shut-off during many years of operation.

The Alfa Valves butterfly valves have a 100% tight shut-off on top and bottom shaft seal due to primary and secondary stem seal within the precision bonded liner. We do not use the traditional o-ring construction on the drive shaft, which could weaken the shaft.

The bonded liner creates a 100% tight-off on the process connections due to extended rubber lining beyond the flanges facing, no flange gasket required.

The bonded liner concept will create a corrosion proof design, complete elimination between body and liner. Bonded liner fully covers the valve body internally.

Due to the vulcanisation process all Alfa Valves valve bodies are extremely strong and are vulcanised at ± 150 Bar and can be used as fully pressure rated dead-end service valves for MONO S 60 and S 61, Double flange S 46 and LUG S 64.

All our valves are suitable for vacuum (negative pressure) services and high fluid velocity applications.(Liner cannot be sucked into the pipeline).

Alfa Valves Bonded liner concept ensures that the liner cannot move around as a result of which;

  • No tearing and distortion of the liner
  • Very low wear of the seat
  • Reliable low torque figures
  • Exceptionally long seat life up to 3 x longer than replaceable liner valves
  • Permanent dry lubrication free design due to stainless steel stem and bronze bearings
  • Uniform sealing, bi-directional flow
  • Low torque due to one shaft design