Cla-Val 81-01/681-01 Technical Manual - Manual (Page 7)

• Simple Proven Design
• No-Slam Operation
• Drip-Tight Shut-Off
• No Packing Glands or Stuffing Boxes
• Easy to Install & Maintain
The Cla-Val Model 81-01/681-01 Check Valve is a hydraulically
operated No-Slam Check Valve. This valve opens when the
pressure at the inlet exceeds the discharge pressure. A gradual
rate of opening prevents sudden opening surges. When a pressure
reversal occurs the higher downstream pressure is applied to the
cover chamber through the control tube lines, and the valve closes
drip tight.
This valve is ideally suited for use where a positive shutoff is
required. The rubber disc assures tight sealing even if the fluid
contains grit or other small-size particles. The simple packless
design insures reliable operation and freedom from leaks.
Note: The effectiveness of this valve is related to pipeline velocity.
We recommend a maximum flow based on pipeline velocity of
6 feet per second. If pipeline velocities exceed 6 feet per second,
consideration should be given to adding a Cla-Val Model 50-01
Pressure Relief Valve or a Cla-Val Model 52 Series Surge Control
Valve to the system.
Schematic Diagram
Item Description
1 Hytrol (Reverse Flow Main Valve)
Typical Applications
Smaller sizes of this valve are used in pilot control
systems in Cla-Val Automatic Control valves. This
valve can also be used in any piping system where
one-way flow is desired.
Install on the discharge of booster pumps to prevent
return flow into tank when pump is off. Relief valve as
shown is good practice to minimize surges when
pump stops.
CLA-VAL
50-01/650-01
Surge Relief Valve
TANK
Isolation
Valve
Pump
81-01/681-01
Booster Pump
Check Valve
1
Inlet Outlet
Check Valve
For valve sizes larger than 3", use Model 81-02.
81-01
(Full Internal Port)
681-01
(Reduced Internal Port)
MODEL