Scotch yoke actuator

Usually end users have a preference for a certain brand of actuators, we work together with all major manufacturers and can offer any desired brand.​

  • Design types: Scotch yoke, rack & pinion, Flat Yoke®, Rack & gear®, linear, compact​
  • Supply: air, Nitrogen, gas, typically 3-12 barg
  • Action: single or double acting​
  • Fail position: fail open, close or in place.​
  • Materials: Carbon Steel, Stainless Steel, Amalga, Aluminum​
  • Manual operation: jackscrew, hand pump​
  • Quarter turn (VA, GS, SY) & Linear (LP)actuator for on/off or modulating control of any ball, plug, butterfly, gate or rising stem ball valve operated by air, natural gas or nitrogen.​
  • Single or double acting, 3-12 bar supply pressure, -30/100°C​
  • VA : 1.100 Nm​
  • GS&SY : 644.000 Nm​
  • LP : 19.752.175 N​

The founder of QTRCO, Ed Holtgraver, was responsible for field service of a large valve company. He saw customers lose vast amounts of time, production hours and ultimately money from misapplied products. Products that would have worked better had greater attention to detail been applied during the design phase.​ By founding QTRCO, Ed’s intent was to design and build actuators that simply did not encounter field service issues. With a very rugged mechanical design and the elimination of normal failure modes—sliding parts, side load forces and numerous seals—the QTRCO actuators have evolved into exactly what Ed had in mind those many years ago.

Used and/or approved by GE, Shell, Akzo, Baker Hughes, Basf, Bayer, DuPont, Exxon, UOP, Invista, LyondellBasel, PPG, Total.

  • If your regular pneumatic actuator doesn’t last because of extreme conditions QTRCO has the solution and they back this by a 3-year warranty which is independent of the number of cycles.​​
  • If you need a closing time as low as 0,1 seconds​
  • If you need high reliability & maximum availability​
  • If your actuator is exposed extreme environmental conditions (corrosive,
  • high- or low temperatures)​
  • If you require superior control capability (low hysteresis and dead band)​
  • If you require a unique solution for partial stroke, manual override & integrated lockout)​

Industries served: food & beverage, (petro)chemical, power, oil & gas, pulp & paper, nuclear and more.​

Available material (combinations): ​ Ductile Iron, Carbon Steel, ​Stainless Steel, Amalga composite.​

Reliability by design:

  • Zero side loading on the shaft bushings​
  • Pressure balanced shaft eliminates thrust force​
  • Massive shaft bushings​
  • Zero cantilever forces​

Quarter run

  • Q series Rack & gear® SA: 847 Nm, DA: 2.374 Nm​
  • T series Rack & gear® SA: 847 Nm, DA: 2.374 Nm​
  • F series Flat Yoke ® SA/DA: 56.500 Nm​
  • Linear​
  • L series 200.170 N​

    Temperature -60°C to 204 °C​

    One quarter turn actuator that is fail close and fail open just by turning it upside down​

Suitable for (environmental) extremes:

  • the basis: robust design & premium materials​
  • high and low temperature construction options​
  • high speed stroking capabilities​
  • standard design suitable for high cycle applications​
  • complete SS construction available​

    Customers have reported over 15.000.000 cycles without failure. ​

Maximum availability with low cost of ownership

  • If necessary, seal replacement can be done while the actuator is on the valve
  • Dual travel stops eliminate the need to recalibrate the switches or positioner.
  • Spring return actuator cylinders can be turned while the actuator is on the valve, a new sealing surface is provided with the “inherent” on board spare part.​
  • Non-proprietary actuator seals are readily available. This is the only seal in the actuator.​
  • Captured springs located inward of the pistons allow fast and easy maintenance.​

Temperature capabilities

  • Ultra low -60 / 85°C​
  • Low -50 / 85°C​
  • Standard -29 / 85°C​
  • High -29 / 200°C​
  • Limits may be extended with proper insulation​

Superior control capability

  • Take away the lag and drag so you know when the actuator and valve start and stop:​
  • minimal friction by design, less hysteresis & variability ​
  • tighter tolerances to reduce backlash & hysteresis​
  • elimination of side loading force​
  • tighter tolerances for valve to actuator connection to reduce dead band.​

Actuator design that resolves every issue with currently available partial stroke testing solutions.​

Scotch yoke design Effect Flat yoke® solution
Long & heavy spring on one end, small and light piston on the other Imbalanced weight with SR, stress on the valve “neck” and piping & possible mounting & space issues. Balanced weight design: less space & weight, no stress on the valve and piping.
Single yoke arm design Imbalanced internal forces: wear & torque reducing friction Balanced force design: zero side loading
Piston pressurized on body side Piston rod seals required Design without rod seals
Proprietary rod seals Expensive, not readily available Design without rod seals
Piston rod seals wear Complete actuator disassembly when replacement is required Design without rod seals
Piston rod self supporting or support structure in body Side loading on piston rod Design where side loading is absorbed in body, non applied to the rod.
Fail action reversal requires parts to be placed at opposite side Actuator needs to be disassembled by trained personnel in the workshop Design where actuator only needs to be turned upside down
Travel stops are on yoke arm Piston and spring forces continuously to act with maximum values on yoke arm. The inward and outward piston motion is stopped directly by using aligned travel stops
Rack & pinion design Effect Rack & Gear® solution
Piston axis align to cylinder bore Exhibit high friction % wear from internal cantilever-initiated forces Offset cylinders so that piston axis align with gear PCD. No damaging forces
Outward forces push rack against the cylinder wall Creating friction & motion resistance as rack slides against the cylinder Eliminate contact between rack & cylinder. No contact no friction.
Shaft seals are pressurized every cycle Seals will wear, complete disassembly required to replace Move springs inward of cylinders. Pressurize SR actuators between piston & end cap. Non pressurized seals don’t leak.
Bottom end of shaft bigger than upper: ​
shaft pushed down
Additional friction & wear Balanced shaft: no up or down forces
Shaft & mounting geometry are different on top and bottom side of the actuator Disassembly required to reverse actuator action Top & bottom are identical. Just turn the actuator to change fail action. No disassembly required.
Complete disassembly required for maintenance Removal from valve required Standard possible to replace piston (only) seals with actuator on the valve.
Cylinders are an integral part of the actuator body If cylinders are damaged the complete actuator needs to be replaced Cylinders are a separate component to enable replacement. With SR actuators cylinders can be turned in the field (inherent spare part)
Not all springs are captured Safety can be an issue during service All springs are captured. Safety is improved.
Sometimes the travel stop only contacts 1 piston or a single cam is used.​ Travel stops create side loading, friction & shaft wear Both pistons are stopped simultaneously: zero side loading
Need to let it flow? Call on Wegman!