Knife Gate Valve
The Knife Gate Valve is a uni-directional wafer valve for general industrial application. The nominal widths available range from DN50 to DN1200 with flange connections complying with EN 1092-2 PN10 or alternatively, ANSI B16.5.
To be able to cover a very wide range of use and offer ideal application-related solutions it is available in 3 different types (A, B, C).
(A) Knife Gate Valve Type A
uni-directional wafer valve designed for general industrial service applications
(B) Knife Gate Valve Type B
bi-directional wafer valve designed for media with high consistency
(C) Knife Gate Valve Type C
uni-directional wafer valve designed for indus- trial bulk handling service applications (powdered and granular products)
Applications of Knife Gate Valves
The Knife Gate Valve is predominantly used in the paper and pulp, chemical, and mining industries, in power station technology and the food industry.
However, they are increasingly being used in biogas plants, sewage treatment plants, and in the sugar, steel and animal feed sectors.
Knife gate actuator versions
Drive variants offered for the knife gate valve include a manually actuated handwheel model with rising or non-rising stem, or alternatively a hand lever drive, or double-and single-acting pneumatic cylinders (spring return) and electric actuators.
The structure of the unidirectional knife gate valves encompasses a so-called wafer style cast monoblock body, with raised face and reinforced ribs for larger nominal diameters for extra body strength.
The slide plate is manufactured using stainless steel AISI 304 or AISI 316 as standard. The plate radius of the knife gate valves' slide gate has a bevelled cutting edge. As a result, solids can be cut through and a tight seal can be achieved in the closed position. On request the thickness of the knife gate valve's plate can be increased for higher operating pressures and/or higher quality material can be used.
The slide plate's seat in the monoblock body is sealed tight by an elastomer seal in a stainless steel retainer ring; however, this can also be achieved without the elastomer seal (sealed with metal). The standard material used for the elastomer seal is EPDM. Alternatively, nitrile, viton, PTFE or silicone (FDA certification) is available.
The gland packing consists of several layers of braided fibre. An EPDM o-ring is additionally integrated into the layers of the knife gate valve's gland packing as standard. In addition to greased cotton, a PTFE-coated synthetic fibre, braided PTFE, graphite, ceramic fibre or Dynapack can be used for the braided fibre.
Maximal operating pressures of Knife Gate Valves:
10 bar (higher pressures on request)