Separate Gas Power and Hydraulic Override Systems
Utilizing separate cylinders for the high pressure power gas and the manual hydraulic pump eliminates the commingling of gas and oil and therefore eliminates the possibility of oil release to the atmosphere during valve operation. The direct gas actuator utilizes 50% to 75% less natural gas during operation than traditional gas-over-oil system design, primarily because there is no dead tank space to fill at the beginning of the actuator stroke.
The completely sealed, closed loop hydraulic system for the manual hand pump included provides smooth, efficient operation. When pipeline pressure is not available, the manual hand pump can be used to safely and reliably open and close the valve at its maximum torque requirement. Independently adjustable opening and closing speed controls are built into the manual hand pump module and are easily adjusted in the field without the need for special tools. This closed loop hydraulic circuit eliminates the costly maintenance process to regularly drain collected condensation from the gas/oil tanks, as well as the costs of refilling tanks, the costs of spillage, and the problems associated with disposal of the used oil. In addition, this system utilizes 75% less on-board oil than a gas-over-oil system.
Canted Scotch Yoke Design
The canted scotch yoke mechanism provides high breakaway torque at the beginning stroke resulting in smaller cylinders, which reduces cost and gas consumption. All direct gas actuators utilize Teflon impregnated, sintered bronze bushings on a heavily chrome-plated guide bar to absorb any side loads, guaranteeing smooth operation and longer cycle life.
Linear Travel Stops
The externally adjustable travel stops are on center with the piston rod, eliminating side loading to the scotch yoke. Located at either end of the actuator, these travel stops provide precise adjustment. Both the open and close travel stops are independently adjustable.
Electroless Nickel Plated Cylinders
Both the gas and hydraulic cylinder walls are electroless nickel plated and precision honed to ensure long lasting, trouble free service. All pistons are furnished with a Teflon impregnated graphite guide ring (wear band) that eliminates any possible metal to metal contact. The piston and rod seals are made of Teflon rings preloaded by an O-ring suitable for the most severe working conditions.
