Q-Series Rack & Gear Valve Actuators
QS and QD Series
- Ductile Iron & 316 Stainless Steel constructions
- Rack & GearTM mechanism
- CF8M shaft and rack in all sizes and versions
- Torques to 14,000”#
- Single & double acting
- 90 degree rotation + 5 each end
- Pressures to 150 psig
- Temperatures from –60F to +400F
- Cycle times as fast as 0.1 seconds
Designed to Outperform
- Fewer seals yield fewer failures
- Reduced friction for extreme longevity
- Offset cylinders reduce internal stresses
- Captured springs for safety
- Action reversal by turning top side down
- Outstanding throttling capabilities with optional throttling certification available
- Exceptional corrosion resistance with stainless steel construction
- Handles vibrating pipes with ease
Lower Installed Cost
- Non-proprietary commodity seals
- Piston seals replaceable while actuator remains installed
- Contaminant damaged seals quickly replaceable in line using inexpensive commodity seals
- Reversible SR cylinders serve as spares if damaged
- Seal replacement does not require accessory recalibration
- SR version uses less air volume than most competitors saving $ and eliiminating valve jump
- Partial stroke
- Top mounted lock outs
- Dribble control
- Anti-water hammer
- High speed / low speed
- Manual override
- Solpaq direct NAMUR solenoid mounting
- Universal mounting capability
- “Close mount” on extended stem valves
The QTRCO Rack & Gear® design offsets the cylinders to where the piston axis is aligned to the pitch circle diameter of the pinion gear. This means that the piston forces cause no side loading of the piston into the cylinder wall. The lack of side loading means less friction and thereby less wear. Additionally, throttling (modulating) quality is improved as there is less sticking and stick/slide action of the piston.
Standard Rack & Pinion actuators have rack gear teeth that are off center of the piston axis such that when spring or air force is applied to the piston, there is a cantilever induced side force that pushes the piston into the cylinder wall.
To account for the side loading, R&P designers include wear pad material on the piston skirt to lessen the wear between the piston and the cylinder. Initially the wear pads do not fully conform perfectly to the cylinder bore but they ‘wear in’ after some number of cycles. The greatest problem with wear pads is that they slide against the cylinder bore and they “stick” when stationary and cause stick/slide motion when used for throttling applications.
THE PATENTED RACK & GEAR® MECHANISM WITH LOW FRICTION ROLLERS AND TWIN SIDE RAILS compliment the cantilever force eliminating offset cylinders to result in an extremely low friction actuator that, in the DA version, can be operated using only one’s breath pressure (see video).
Reduced friction, while extending cycle life, also provides for excellent throttling control.
The shaft drives are double square female and are over sized to allow use of adapters for mounting flexibility.
Should the normal ISO bolt pattern not be ideal for an application, there are extra mounting holes that can be used to bolt on a Universal Mounting Plate (UMP) that can be provided with application specific bolt patterns. Usually, we can mount directly to any valve that does not have a protruding packing gland.
The side not against the valve is provided with a removable ‘Top Hat’ that provides the common NAMUR accessory mounting and drive slot. Being removable, this is relocated to the opposite face when action reversal is desired.
Using the inherent mounting flexibility we are readily able to provide ‘Replipaqs’ that convert our normal mounting geometries to precisely match those of competitive actuators. This allows users to replace existing actuators with QTRCO’s with the need for new brackets and couplers.
Our ‘Close Mount’ concept allows Q series actuators to achieve a very compact assembly when driving extended stem valves and the valve shaft is ‘swallowed’ by the through hole actuator shaft and then driven from the top side of the actuator. Typical V type ball valves are excellent candidates as they use the actuator’s throttling capability and compact package size to provide users with a smaller yet high performance product.
Bracket and coupler designs are closely controlled to provide optimum user mounting. An example is out two piece Omega bracket kit that easily and separately mounts to the actuator and the valve and is then brought together to form the final assembly. Fat fingers are not squeezed trying to access hidden fasteners.