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MANUAL VALVE ACTUATORSEngineering Creative Solutions for Fluid Systems Since 1901

TABLE OF CONTENTSMANUAL VALVE ACTUATORScope of Line: Valve Actuators. 1Manual Valve ActuatorDimensional Data . 2MDT Mounting Positions. 2Actuator Characteristic Curves. 3Hand Lever Actuator. 3Actuator Design Parts List. 4Suggested Specifications. 4Buried Service Actuator. 5Buried Service Accessories. 5Diviner Position Indicator. 5Features & Benefits of the Traveling Nut Actuator. 6Optional Actuator Styles. 6Actuator ExtensionsExtension Stem with AWWA Nut. 7Extension Bonnet. 7Floorstands. 7External Packing Bonnet. 7Steady Bearing. 7

SCOPE OF LINEValve ActuatorsWe offer a wide variety ofactuator styles to suit amultitude of applications.Pratt brand valves are availablewith manual, buried service,submersible service, hydraulicor pneumatic, and electricactuators. Every actuatoris specifically designed forlong life in utility service withminimum maintenance.When manual actuation isrequired, the Pratt MDTtraveling nut type actuatoris the ideal option for Prattbrand valves. Our MDT manualactuators are available with a2" nut for buried, submersible or vault service. For above groundapplications, the MDT is available with a handwheel or chainwheel.Hand levers are available for valve sizes up to 10".Actuators for open / close service, throttling or modulating serviceare all available in hydraulic, pneumatic and electric models. Wesupply a variety of actuator accessories. Each accessory is designedto meet specific operating requirements.Each actuator can be mounted in variouspositions for maximum conveniencein installation and operation. We canmount the actuator directly on thevalve, or on an actuator extension to suityour application. The actuator positioncan be rotated about the valve stem asindicated on the project d rawings.Details of our MDT manual actuator andaccessory product offerings are featuredin this bulletin. More information onelectric and pneumatic actuator stylesthat are available to be mounted on Prattvalves, can be found in other bulletins.1

MANUAL ACTUATORSTRAVELING NUT TYPE MANUAL ACTUATORThe Pratt MDT traveling nut type actuator is the ideal manualactuation option for Pratt butterfly valves. The MDT providescharacterized closure, which means the disc travel slows down inrelation to the rotation of the handwheel or operating nut as itapproaches the closed position. This feature helps to minimize thepossibility of line shock and also provides a mechanical advantageat valve closure, where torque is normally higher.Unlike other designs, the Pratt MDT actuator is designed towithstand up to 450 ft. lbs. of input torque (open or closedEnd CoverSpur GearPLpositions) against the stops. This exceeds AWWA C504 designrequirements by 50%. TheMDT actuator maintains exactvalve position under conditionsof fluctuating, turbulent andintermittent flow withoutsacrificing ease of operation.In complete conformity toAWWA Standard C504, thePratt butterfly valve, coupledwith the MDT actuator, offerssingle source responsibilityfor both actuator and valve.PRATT MODEL 2FIIIn order to meet your just inWITH HANDWHEEL ACTUATORtime delivery requirements, wemaintain inventory on 3" through48" butterfly valves with a variety of MDT actuation styles to suityour application. Consult factory for availability.MDT MOUNTING POSITIONSNotes: Clockwise to close (open left) unless otherwise noted.Spur gear and end Cover applies only to the MDT-6S.ChainwheelHandwheelHandwheelPRATTWW DIA.Dia.PRATTV V DIA.Dia.NNOPENPPCLO SEDQSTRRVALVE SIZEMDT SIZEJ3" to 10"MDT-2S4-7/812"MDT-2S4-7/814", 16"MDT-3S5-5/818" to 24"MDT-4S*30", 36"MDT-5*36", 42"MDT-5S*42", 48"MDT-6SMQLOPEN2" St’d.St’d.2"AWWA NutAWWANutPRATTOPENSTANDARD POSITIONALTERNATE OTE: Actuator sizing is determined by flow rate and working pressure operating conditions.2VW# TURNS TO CLOSE89-1/832129-1/8329-1/830

MANUAL ACTUATORSACTUATOR CHARACTERISTIC CURVESThe actuator characteristic curves below illustrate the total travel of the disc achieved by turning the valve actuator (shown inincrements of 10%) from closed to full open position. The Pratt MDT-2S actuator which is used on valves ranging from 3" to 12",features a slotted‑lever design. The MDT‑3S through MDT‑6S used on valves larger than 12" in diameter feature a link‑lever system (seeillustrations on page 4). The MDT actuator provides for maximum slow down as the valve approaches the closed position, thus reducingthe possibility of line shock.Open 90 Open 90 808070DISC POSITION (IN DEGREES)DISC POSITION (IN DEGREES)70605040302060504030201010Closed 0 Closed 0 0%102030405060708090 100%0%405060708090 100%MDT-3S807070DISC POSITION (IN DEGREES)Open 90 DISC POSITION (IN DEGREES)30MDT-2S80605040306050403020201010Closed 0 1020ACTUATOR STROKE (IN PERCENT OF TOTAL TRAVEL)Open 90 0%10ACTUATOR STROKE (IN PERCENT OF TOTAL TRAVEL)20304050607080Closed 0 90 100%0%102030405060708090 100%ACTUATOR STROKE (IN PERCENT OF TOTAL TRAVEL)ACTUATOR STROKE (IN PERCENT OF TOTAL TRAVEL)MDT-4S AND MDT-5MDT-5S, MDT-6SHAND LEVER STYLEVALVE SIZEACTUATOR SIZEK3" to 6"L -12"12We offer extra heavy steel hand leversfurnished with a comfortable non-metallichand grip for easy operation.8" to 10"L -18"18For throttling, the lever is moved to anyStandard lever lengths are 12" for valvesthrough 6" in size, and 18" for8" and 10" valves.3NATPR Tdesired position and locked with a wing nutto eliminate vibration or chattering.PEOur hand levers operate similarly to a teewrench, and are available for valves sizesup to 10".KO

MANUAL ACTUATORSACTUATOR DESIGN PARTS LISTSLOTTED LEVER (4"–12")1. Housing — Provides structural support plusprotection for internal operating mechanism.Mounts to valve trunnion with four bolts. Gasketbetween housing and cover prevents infiltrationof dirt and moisture.LINK-LEVER (14"–48")16347542532. Screw Rod — Precision-machined, high strengthsteel.3. Stop Limiting Collars — Built-in, threadedinto position and pinned. Exceeds AWWA C504standard for input torque requirements toeliminate the possibility of damage to actuatorhousing, mechanism or disc-shaft assembly.4. Lever — Rugged casting built to transmit torquesfrom slider nut to valve shaft. On link-lever design,takes up higher portion of nut movement at the“closing” end of the screw.5. Key — Actuator is keyed to valve shaft.6. Slider Nut — Precision machined to mateperfectly with screw rod and lever. Capable ofwithstanding 450 ft. lb. input torque against stopcollar.7. Dual-Link Construction — One link above thescrew (shown) and one below (hidden), addsstrength and prevents misalignment and jammingof slider nut.SUGGESTED SPECIFICATIONSManual actuators shall be of the traveling nut, self‑locking type andshall be designed to hold the valve in any intermediate positionbetween fully open and fully closed without creeping or fluttering.Actuators shall be equipped with mechanical stop‑limiting devicesto prevent overt ravel of the disc in the open and closed positions.Valves shall close with a (clockwise) (counter‑clockwise) rotation.Actuators shall be fully enclosed and designed to produce thespecified torque with a maximum pull of 80 lb. on the handwheel orchainwheel. Actuator components shall withstand an input of 450ft. lbs. at extreme actuator position without damage.4PRATT MDT ACTUATOR IN ASSEMBLY

BURIED SERVICE ACTUATORRUGGED, FEATURE PACKED CONSTRUCTIONDesigned and developed by us specifically for buried serviceapplications, our buried service MDT traveling nut actuator ismounted on the Pratt Groundhog butterfly valve. The buriedservice MDT actuator is lubricated for the life of the valve. Becauseof its fully grease packed construction, the actuator can beoperated without maintenance under ground-water conditions. Aslong as the cover, gasket, and seals remain intact, there is no needto worry about damage resulting from water infiltration.Completely in conformity to AWWA Standard C504, our buriedservice MDT actuator has a mechanical stop which will withstandan input torque of 450 ft. lbs against the stop. It can be relied uponto maintain exact valve position under conditions of fluctuating,turbulent and intermittent flow.PRATT GROUNDHOGWITH BURIED SERVICE ACTUATORBURIED SERVICE ACCESSORIESA variety of accessories can be used with our buried service MDTactuator. A conventional valve box or five inch soil pipe can beused to provide ready access to the AWWA nut (by means of a teewrench) after backfilling. These items can be obtained from yourlocal Pratt distributor.PRATT DIVINER GROUND LEVELPOSITION INDICATORThe Pratt Diviner is a valve position indicator used for buriedvalves to enable you to identify valve position at a glance, directionand number of turns to open or close the valve. It is installed in astandard 5-1/4" buried valve box just below the removable valvebox cover. The Diviner position indicator is used in conjunctionwith an extension stem (see Actuator Extensions on page 7) that isavailable in 5' or 10' lengths at an additional cost.TYPICAL 5" SOILPIPE APPLICATIONThe Diviner position indicator is shipped for field assemblycomplete with cast iron adapter (1) and cap screws, guidebushing (2), position indicator (3), flexible washer (4), and atwo-inch square AWWA nut (5) with set screw.The adapter fits a standard 5-1/4" valve box (6) or 5 inch castiron soil pipe bell utilizing a cast cover with skirt depth of 1"or less (7). Extension stems (8) are available in 5‑foot and10‑foot lengths and can be ordered separately at extra cost.DIVINER GROUND LEVELPOSITION INDICATOR5

FEATURES & BENEFITSTraveling Nut ActuatorFEATURES OF THE TRAVELING NUT ACTUATOR BENEFITS OF THE TRAVELING NUT ACTUATOR Specifically Designed for Quarter Turn Valves The peak output torque of a traveling nut actuator occursat the same position as the peak torque requirement of thebutterfly valve. Slows Down Valve Travel as the DiscApproaches the Closed Position The traveling nut actuator controls the valve disc withextreme precision which reduces disc vibration and chatter. Threaded Input Shaft The traveling nut actuator has many threads which keep theinput shaft free from stress, therefore creating lower contactpressures. Input Stops are Rated at 450 ft. lbs. The input stops are capable of withstanding 1-1/2 times theAWWA C504 required input torque at full open or closedpositions without damage to the valve or actuator.OPTIONAL ACTUATOR STYLESSUBMERGED SERVICE ACTUATORSCYLINDER AND ELECTRIC MOTOR ACTUATORSAt our manufacturing facility, the buried service MDT actuatorcan be converted to an actuator which is suitable for continuoussubmerged service. Our capable engineering staff will evaluateyour specific submersible conditions, and determine the MDTdesign modifications necessary to suit your application.Pratt valves can be equipped with a wide range of cylinderand electric motor actuators to meet your special operatingrequirements. Consult our factory for additional information.WORM GEAR ACTUATORSWe furnish worm gear actuators upon request. We offer a varietyof different manufacturers’ designs tailored to each projectspecification requirement.6