Emerson 788 DVC manual Cup-seal Replacement on Existing AP Option Piston, Retrofit

DANIELTM MODEL 788DVC DIGITAL CONTROL VALVES D E C 2012

5.4Cup-seal Replacement on Existing “AP” Option Piston

If your Daniel Valve is being modified to accommodate applications requiring the use of aggressive products used in petroleum blending operations, the following procedures should be followed in retrofitting your valve.

Retrofit

5.4.1To Replace Existing Standard Cylinder Assemblies with the Current Daniel “AP” Option:

a.Remove original cylinder assembly as shown in Section 5-1. The cylinder assembly will be supplied from the factory with or without an indicator (specified on order).

b.Clean and inspect O-ring sealing surfaces in the main valve body. Apply a lightweight lubricant to these surfaces before installing the new cylinder assembly.

c.Lower the “new” cylinder assembly and cylinder head into the valve body. Align the bolt holes in the cylinder head with the studs in the main valve body.

d.Fasten the cylinder head into position using retaining nuts. Tighten nuts, alternating to opposite sides, to assure a uniform seat.

e.Return all tubing and/or valve accessories to their original position.

f.The cup-seals (27) should be protected at all times against damage or distortion of any kind.

g.Proper installation dictates that cup-seals (27) be installed with the closed ends facing “in”.

DISASSEMBLY AND REASSEMBLY 5-5