81-01 Check Valve

Product Advantages

  • 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 Check Valve is a hydraulically operated NoSlam 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.  100-10 Hytrol Main Valve

Optional Features

Item Description
P.  X141 Pressure Gauge
V.  X101 Valve Position Indicator

Series 581 Pressure Loss Curve

For valve sizes larger than 3″, use Model 81-02.

Typical Applications

Smaller sizes of this valve are used in pilot control systems in Cla-ValAutomatic 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.

Model 81-01 (Uses 100-01 Hytrol Main Valve)

Pressure Ratings (Recommended Maximum Pressure – psi)


Model 81-01 Dimensions (In Inches)

Model 81-01 Metric Dimensions - (Uses 100-01Hytrol Main Valve)

Model 81-01 Dimensions (In Inches)

100-01 Hytrol Main Valve

Flowrates shown are for a velocity of 6 fps (1.8 m/s).
Velocities can be increased to 10 fps (3.05 m/s) if required, and the installation of a surge valve in the system is recommended in velocities above 6 ft/sec. (1.8 m/sec)

Pilot System Specifications

Temperature Rating
Water: to 180°F / 82°C Maximum

Speed Controls
For valves with opening and closing
speed controls order Model 81-02

Standard Pilot System Materials
Fittings: Brass
Tubing: Copper
Optional Pilot System Materials
Pilot Systems are available with
optional stainless steel or Monel

When Ordering,
Please Specify
1. Catalog No. 81-01
2. Valve Size
3. Pattern – Globe or Angle
4. Pressure Class
5. Threaded or Flanged
6. Desired Options
7. When Vertically Installed