Series CPI-IN In-Line

The Series CPI-IN Check Valve can handle corrosive or abrasive materials such as raw sewage, sludge, or slurries. With a broad selection of elastomers, the Check Valve is suitable for many types of media and a wide range of temperatures.

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  • CPI-IN

  • Cuff: The round portion of the valve connecting to the valve taper. The cuff will be compressed between the expansion clamp(s) and the pipe’s inner surface

    Taper: The taper transforms the round shape of the valve cuff to the vertical shape of the valve bill. Reinforcement in the taper is customized to suit each application’s expected inlet pressures and backpressures.

    Bill: The outlet end of the valve. The bill contorts to allow flow through the valve yet closes tight during ‘no flow’ or reverse pressure conditions. The bill can be straight or curved (depends on application).

    Tube: The inner surface or valve ‘sleeve’. This is constructed using an elastomer most suitable for the process fluid.

    Cover: The outer surface of the valve. This is made from an elastomer most suitable for the expected operating.

    Expansion Clamp(s): Supplied with the valve, the duckbill cuff is ‘sandwiched’ between the pipe inner walls and the expansion clamp(s).

    Line Pressure: The fluid pressure applied to the valve inlet (used to open the valve).

    Backpressure: The fluid pressure exerted on the valve outlet. Usually measured in feet or meters of fluid above the pipe invert.

    1. The inside of the pipe must be smooth and free of burrs and sharp edges. This will prevent damage to the duckbill check valve. Before installing the valve, verify the fit by measuring both the ID and the OD of the valve.

    2. When the check valve is safely positioned, install the inner clamp(s). Where two or more clamps are required, they should be equally rotated relative to each other. This will ensure even pressure, making the clamps more effective.

    3. Torque the clamps until fully extended to ensure a tight fit inside the pipe. This will prevent the valve from falling or slipping out of position. DO NOT use a lubricant to aide in the installation of the valve onto the pipe as this could cause the valve to slip out of position.

    4. For check valves 24” or larger, it is recommended that the valve be anchored to the outfall pipe. The potential energy generated by an outfall, on large diameter check valves, could be significant, and may eventually push the duckbill check valve of its pipe. The metal clamps on check valves are provided with drilled holes for anchoring. These holes are used as a pattern for drilling through the rubber and the outfall pipe. Installed bolts should be 90 degrees to the clamp. See “Securing Check Valve Instruction” for clarity.

    5. For duckbill check valves of 18” diameter and larger, proper nylon slings and lifting equipment should be used to place the valve into position.

    If the valve does not fit properly:
    During the installation, if fit appears to be a problem.

    If the valve will not close fully or check flow in the reverse direction:
    Possible obstruction in the line. Inspect the valve for entrapped foreign objects, which may have lodged between the lips of the valve.
    The backpressure may not be sufficient to seal the bill completely.

    If the valve moves out of position in the pipe or has a loose fit:
    Check all clamp bolts are sufficiently tightened. Refer to the installation instructions.
    The valve may not be fully seated in the pipe.
    The cuff OD of the check valve may be too small for the pipe ID.

    Preferred Orientation
    For best performance, bills should be installed as close to the vertical position as possible. Depending on valve size, clamps should be installed as follows:

    a) Under 28” Nominal Diameter – These are supplied with a single clamp. The clamps and turnbuckle are oriented at centre at the top/centre.
    b) 30” to 48” Nominal Diameter – These are supplied with two clamps. The turnbuckles should be oriented 180° apart, at top and bottom.
    c) 54” and above – These are supplied with three or four clamps. This depends on the application. When installing with three clamps, the turnbuckles should be oriented 120° apart. Four clamps should be oriented 90° apart.

    Periodically, an inspection should be performed to verify the valve’s performance.

    If a build up of debris occurs within the valve, line pressure should flush it out. In some instances, a wooden plank 1” x 4” or 1 1/2” x 12” may be temporarily inserted into the bill of the valve and rotated 90°. This will clear the check valve of any debris that may be trapped in the bill.

    A periodic visual inspection of the valve is also a good idea. Inspect the tube and cover for cuts, checking, and fissures. Do not be alarmed if small cuts have formed in the outer cover. If necessary, repairs can be made on site with a repair compound. If significant fissures are noticed where fabric is exposed and torn, the valve must be replaced. Upon inspection of the inside of the bill, if blisters, deformation, or delamination is noted, this is an indication that the media or higher than expected temperatures are attacking the tube. The valve should be replaced as soon as possible. Further research into the actual operating conditions (media and temperature), is required so that a more appropriate check valve may be supplied.

    EVR Duckbill Check Valves are custom made and are intended for specific applications. They are designed to respond to criteria unique to its purpose, such as line pressure, backflow pressures, and chemical compatibility. Should the conditions be altered or changed significantly, it could affect the normal operation of the valve.

    EVR duckbill check valves function based on differential pressure. When the line pressure, (at the valve inlet), exceeds the backpressure, (at the valve outlet), the valve opens and flow is created (left picture). When the backpressure exceeds or overcomes the line pressure, the bill of the valve seals shut, thereby preventing any backflow from occurring, (right picture).

    1. 24” diameter duckbill check valves and larger must be secured to the outfall pipe using anchor bolts as shown on “DETAIL B”.

    2. After the valve and the clamps have been properly installed, using the pre-drilled holes in the inner-clamp(s) as a guide to drill through the duckbill cuff and into the pipe. Ensure the proper equipment is used.

    3. After the anchor bolts are in place, tighten them until the thickness of the clamp is imbedded into the cuff of the valve.

    4. If the anchor bolts are exposed on the outside of the outfall pipe, do one of the following:
    a) Weld the anchor bolts to the pipe if it is a steel pipe or
    b) Use nuts and washers to hold the anchor in place. To prevent any leaks, a rubber washer must be placed between the pipe wall and the nut.

    5. When two clamps are used, one clamp should be anchored. When using three or four clamps, two clamps should be anchored.

    Duckbill check valves should be stored vertically with the bill facing upward, not on its side, horizontally in a cool, dry location with maximum ventilation.
    Check valves should not be stacked nor should anything be stored on top of the valves’ bills. They should remain on a skid until ready for use.

    Do not drop, bend, or twist the valve as damage may occur.

    The valve should be wrapped in black plastic to avoid contact with sunlight and/or ultra-violet light. This will extend the shelf life.

    Avoid exposure to light, electric motors, dirt, or chemicals. Resilient check valves are subject to deterioration when exposed to ozone and non-compatible chemicals. Ozone, especially, may cause the rubber to harden and become brittle.

    Store the Installation Operation Manual with the valve so it will be readily available for installation.

    All EVR products are guaranteed for one full year against defects resulting from faulty workmanship or materials. If any such product is found to be defective by reason of faulty workmanship or materials, upon written notice and return of the product, the defective product will be replaced by us free of charge, including the shipping charges for the replacement product. Claims for labour costs and other expenses required to replace such defective product, or to repair damage resulting from the use thereof will not be allowed by us. Our liability is limited to the price paid for the defective product. EVR Products shall not be bound by any warranty other than the above set forth unless such warranty shall be in writing. This literature is published in good faith and is believed to be reliable, however, EVR Products does not represent and/or warrant in any manner the above information and suggestions contained in this brochure. Data presented is the result of laboratory tests and field experience.