OPERATION AND MAINTENANCE INSTRUCTIONS
          For The Franklin Valve-DuraSeal Valve

OPERATIONS

The Franklin DuraSeal Valve is a resilient seated, non-lubricated, plug type valve which utilizes a mechanical action to perform seating and unseating functions.  Opening the valve, the plug is raised retracting the seating slips through their tapered connections.  Only after the slips are fully retracted perpendicularly from the body seat, the plug is rotated to the open position.

Closing the valve, the slips and plugs rotate freely with no seal to body contact until the slips are positioned over the ports.The plug is then driven down between the slips and the tapered surfaces wedge out the slips for a positive upstream and a downstream shut-off.  For maximum upstream sealing, it is very important to torque the valve closed.

The small DuraSeal Valves are handwheel operated, and require 2¼ turns to open or close.  Turning twice expands or retracts the slip, while ¼ turn rotates the plug.  Large DuraSeal Valves operate in a similar manner, except they utilize torque reducingright angle worm gears. 

A position indicator flag shows the exact plug position at the top of the operator.  It appears in line with the flow when the valveis open and perpendicular to the flow when the valve is closed.  When DuraSeal Valves are used for double block and bleed service, a manual body bleed valve is required to check seal integrity of the valve in the closed  position. 

DuraSeal Valves hold bubble tight and as a result trap internal pressure. This pressure is subject to thermal expansion and can cause a thermal lock. To prevent pressure build up in the body cavity, thermal relief systems or automatic bleed valve systems are recommended.

On valves equipped with thermal relief systems, the body isolation valve (found behind the body flange) must be left open during normal use.  The relief valve will open at 25 psi differential pressure, on all valves, and can relieve to any location(normally upstream side of the valve).  Thermal relief systems are also provided with a manual body bleed valve to check valve seal integrity. 

All DuraSeal Valves are manufactured with either an integral handwheel operator or an integral right angle worm gear operator.Both operators are connected to valve stem by a coupling pin. This pin is visible when the valve is in the closed position and lines up with cast holes on the side of the lower gear housing. The valve operator can be removed for inspection by simply driving the coupling pin out and removing the mounting bolts.

On gear operated models the handwheel position may be changed as follows:

  1. Place valve in full open position. 

  2. Remove gear housing cap screws. 

  3. Turn handwheel to further open the valve – this will turn gear housing.  Continue this until handwheel comes to a desired position and the gear housing mounting holed are aligned. 

  4. Replace gear housing mounting cap screws. 

Be sure short cap screws are inserted below worm on worm shaft. 

MAINTENANCE

The Franklin DuraSeal Valve needs no day-to-day maintenance; however there are some services which may be needed occasionally.

1. Occasionally, drain plugs in the lower plate should be removed and the residue flushed and drained.  In cold climates but before freezing weather has occurred, any possible collection of water below valve plug or plug trunnion should be drained out through the lower plate drain plugs.  To displace and prevent moisture from accumulating and freezing, keep the valve operator housing full of lubricant.  The operator is provided with a grease fitting.  Lubricant should be injected with DuraSeal Valve in the open position only.  Use lithium 12 hydroxyl stearate or lithium base mol disulfide grease.  Under ordinary conditions, a few pumps of the grease gun semi-annually are sufficient.

2. If the body bleed should indicate an upstream leak which cannot be stopped with ordinary force on handwheel, this may be stopped by one of the following:

    • Operate valve through open-close cycle while fluid is flowing to flush out valve body.  After several flushing attempts, close DuraSeal Valve and check body bleed again.  If necessary, slips should be inspected and replaced if body bleed still indicates valve leak.

    • The line must be drained to inspect slips.  Then place DuraSeal Valve in open position and check body bleed valve for zero line pressure and remove lower plate.  In most cases, the lower plate can be removed by removing the hex nuts that hold the lower plate and rotating the valve to the closed position. This action will push the lower plate off of its seal and allow the lower plate to be removed. After the lower plate has been removed, cycle the valve to the open or the unseated position and this will then allow the slips to be removed from the plug dovetails.  Slips can be pulled off dovetails and inspected or replaced if damaged.  It is recommended to replace lower plate O-ring and gasket any time lower plate is removed.

      The valve operator and bonnet can be removed and slips can be replaced from the top of the valve if the lower plate is not accessible for replacing the seating slips.

      CAUTION:  Check body bleed for zero line pressure before removing bonnet.

3. If stem packing fails, it can be changed as follows:

    • Remove operator.

    • Remove packing gland and replace inner and outer O-rings and backup ring.

    • Remove and replace packing rings carefully.

    • Replace packing gland.

    • Replace operator.

4. To change operator heads:

    • Shut down line pressure.

    • Close DuraSeal Valve.

    •  Open bleed valve for zero pressure when removing operator.

    • Drive out coupling pin.

    • Remove housing mounting bolts and lift operator off.

    •  Replace new operator in reverse order and insert coupling pin from same side as guide pin boss.

    •  Close bleed valve.

    •  Check operation of DuraSeal Valve.

NOTE:

Franklin Valve maintains a supply of slips and seal kits for the DuraSeal Valve as well as other parts. An exchange program is offered on slips, send the old cores in for rebonding and Franklin will exchange them for a new or rebounded pair and a 50% credit will be allowed.

When ordering parts for the DuraSeal valve, make sure that the flow media is known. The DuraSeal valve utilizes different rubber compounds to work with the many products that can flow across the valve.

WHEN PERFORMING MAINTENANCE ON THE DURASEAL VALVE, ALWAYS MAKE SURE THAT THE VALVE AND IT’S COMPONENTS ARE FREE OF ANY LINE PRESSURE OR ANY MECHANICAL PRESSURE THAT MAY EFFECT THE OPERATION OF THE VALVE.

©2010 • DuraSeal is a registered trademark of Franklin Valve L.P.