The offsetting of the shaft in two axis, when combined with the tilting cone / ellipsoidal segment means that there is complete removal of 'scuffing' and surface pick up during the full 90 degree movement. The seal ring, which is of laminated construction, uses the seat ring as the stopping point, eliminating separate mechanical stops. There is no need for critical settings for disc-to-seat contact to achieve required shut-off. This is beneficial in situations where actuators and controls are fitted.

When closed, the seat is bi-directionally tight, with a zero leakage rate in either direction. The seat sealing load is torque induced, thus when the disc movement reverses to 'open', the operating torque quickly reduces, due to the on / off contact action of seal to seat and swing clear action via shaft offsets. Since the seal action is 'contact' without 'rubbing' action, then galling does not occur, allowing the same material to be used for both seal and seat.

PWR, BWR, CANDU

• Service Water
• Component Cooling Water
• Containment Purge/Vent Isolation
• Alt. Decay Heat Removal, RHR System
• Radiation Waste Control Isolation
• Air Header System
• Sump Floor Drain-Containment Isolation
• Heater Drain
• Condensate Polishing
• Condensate/Feedwater Loop
• Hydrogen Cooler Heat Exchanger System
• Raw Water Treatment

The valve is a bi-directional tight shut-off device incorporating a resilient seal mechanically retained around the periphery of the valve disc. The seal is available in various types of elastomers, the selection being dependent on the valve duty and working pressure and temperature. The seal seats against a metal face machined into the body of the valve. Positive shut-off is achieved without excessive interference between seat and seal ensuring maximum seal life and low seating and unseating torques.

The E-Series has an ebonite lining which is a hard, natural rubber, bonded and autoclave cured to achieve maximum strength and adhesion. It has a corner locking overlap feature around the flange and shaft bores to maintain optimum stability. The seat contact area, against which the resilient disc seal ring locates, is fully machined to ensure consistently tight shut-off.

In operation, there is a key difference when compared with other rubber lined valves. The ebonite is part of the structural rigidity of the body and the resilient seal is disc located. This is the element being compressed during sealing on closure. This eliminates dragging on the liner, which occurs on other valve designs where the disc is solid and the seal is made by compression of the liner. It is particularly effective in high-chlorine environments such as brackish water and seawater, where the natural resistance of Ebonite insulates the wetted portions of the valve body from corrosive attack by such aggressive media. The use of Ebonite in this application allows the use of Carbon Steel valve bodies, and actually makes them more corrosion-resistant than stainless-steel bodies in brackish water applications.

PWR, BWR, CANDU

• Ocean Water Discharge
• Condenser Waterbox
• Circ Water
• Various Other Applications