Emerson 788 DVC manual Cylinder Disassembly

D E C 2012 DANIELTM MODEL 788DVC DIGITAL CONTROL VALVES

5.2Cylinder Disassembly

Refer to Figure 5-2.

PERSONAL INJURY AND/OR EQUIPMENT DAMAGE

Caution is required when performing any disassembly procedure as the Cylinder head is bolted to a spring loaded cylinder assembly. Service should only be performed by trained and qualified service personnel.

Failure to comply with recommended could result in serious injury and/or damage to the equipment.

1.Position the cylinder assembly in an arbor press with the cylinder head (5) down. Valves smaller than 6" may not require a press. Larger units may require the use of a spindle or arbor press to facilitate removal of the piston assembly, in which case, the arbor should be resting against the cylinder head.

2.Place a metal sleeve over the piston nose to protect the sense line during removal. This can be fabricated from a pipe section and should have an internal diameter large enough to encircle the piston nose. The length must be sufficient to accommodate complete spring compression with allowing the sense line to strike the press plunger.

3.Using EXTREME CAUTION depress the piston against the spring until the rectangular ports are cleared. Block the piston in the open position, fully compressed, by inserting a suitable wedge through the port opening. Any wood, nylon or non-marring dowel or handle that will safely guarantee piston position can be used for this operation. It is recommended that a brass or other soft metal bar be used for this operation.

4.Remove the retaining ring, sealing ring and O-ring.

5.Using EXTREME CAUTION depress the piston against the spring and remove the piston blocks. CAREFULLY remove the piston from the cylinder body while maintaining pressure on the valve spring.

5-2 DISASSEMBLY AND REASSEMBLY