Historically, quarter turn valves have been used almost exclusively for on–off applications. More recently however, the need for use in regulation processes is increasing.

• The majority of pneumatic and hydraulic actuators use scotch yoke technology to transform the linear piston movement into a rotary one. Gaps between the sliding block and the scotch yoke slot inevitably have a negative influence on both precision and the functional dynamics (hysteresis, dead band, small step response, etc). Throughout the operating life of the actuator, this inaccuracy becomes permanent and will consistently worsen.
• Our innovative Zero Backlash mechanism improves performance and solves the wearing-related gap between the sliding block and the scotch yoke slot, maintaining friction at similar levels to even the most established technology.
• Avoid increase in dynamic and static friction.
• Avoid any possible unwanted movement between different parts.
• Allows automatic and continuous adaptations during actuator’s operation.
• Position reliability of the ZB system is 400% times better than a standard mechanism
• It is upgradable on all of IMI STI’s quarter turn range.
• Patented technology.
• Available on the whole range of scotch yoke mechanism