Mark 688 Series
Pressure Regulators
Piloted Soft Seat Regulator (1" - 2")
The Mark 688 Series piloted soft seat regulator
was designed specifically to provide accurate pres-
sure control on very low pressure tank blanketing
systems. The pilot operated Mark 688 responds to
very small changes in tank pressure by throttling
open or closed to maintain the desired pressure
set point.
• Accurate regulation down to 1" wc
• ANSI Class VI Shutoff
• Five available spring ranges
• 200 psi maximum inlet pressure
• High flows: Cv 1" - 17; 1-1/2" - 30; 2" - 45
Mark 688 Piloted Soft Seated Regulators
Specifications
Sizes: 1" (DN25) through 2" (DN50) Service: Tank blanketing only
End Connections Shutoff: ANSI Class VI
• ANSI Flanges — 150#, 300# Available Spring Ranges
Body Materials • MK608 Low Pressure Pilot (psi): 1-5 wc,
• Carbon Steel — ASME SA216 WCB 4-10 wc, 5-30 wc, 0.5-1.75 psi, 1.0-3.5 psi
• Stainless Steel — ASME SA351 CF8M Minimum & Maximum Pressure Drop: 25 psi
Trim Material: 316SS (Standard on all valves) minimum (1,7 bar); 200 psi maximum (13,8 bar)
Main Valve Seat Material: 316SS/Viton Pressure Temperature Ratings (Body):
Actuator Materials Maximum inlet 200 psi @ 100°F
• Carbon Steel for WCB bodies Maximum Outlet Casing Pressure: 185 psi
• Electroless Nickel Plated Carbon Steel for CF8M (12,8 bar)
bodies Flow Coefficients:
Diaphragm Material: Buna-N • 1": 17 Cv
• 1-1/2": 30 Cv
• 2": 45 Cv
Jordan Valve a division of Richards Industries
3170 Wasson Road • Cincinnati, OH 45209
513.533.5600 • 800.543.7311 • 513.871.0105 (f)
info@richardsind.com • www.jordanvalve.com
MK688/0418
Mark 688 Series Piloted Soft Seated Regulator
Dimensions
3/4" FNPT
Sensing Line
Connection
22.56" 573mm
8.17" 17.92" 6.25"
207mm 455mm 159mm
A 8.45" 215mm
B
FLOW
9.88" 251mm
A
View from Outlet Side
Valve Size Ends A
1" 150 9.25" (235mm)
1-1/2" 150/300 8.75"/9.25" (222mm/235mm)
2" 150/300 10.00"/10.50" (254mm/267mm)
Ordering Schematic
Model No Size Body Mat'l 1 2 3 4 5 6
Model 3&4 Trim
688 Standard Seal Materials / Pressure Drop Ranges
V1 316SS / Viton / 25-50 psi drop
Size V2 316SS / Viton/ 50 - 200 psi drop
ZZ Non-Standard
100 1"
150 1-1/2"
200 2" 5&6 Range
608P Pilot
Body Material 01 1 - 5 wc
CS Carbon Steel (WCB) 02 4 - 10 wc
S6 Stainless Steel (CF8M) 03 5 - 30 wc
04 0.5 - 1.75 psi
05 1.0 - 3.5 psi
1&2 End Connections ZZ Non-Standard
I5 150# FE
I3 300# FE
ZZ Non-Standard
