APCO Slanting Disc Check Valves (CSD)



APCO Slanting Disc Check Valves (CSD)

Product Brochure



Superior Flow Characteristics
The APCO Slanting Disc Check Valve, because of its very unique two-piece body design and slanted disc orientation, has superior flow characteristics (lowest head loss) when compared to other check valve designs. The angled body seat allows for a 40% expanded cross sectional flow area, so the area occupied by the mass of the disc is more than compensated for by the expanded flow area. Each body half has an o-ring seal and valves sizes 6″ (150mm) and larger have an access cover for internal inspection on each body half.

Slanting Disc Design Offers Minimal Flow Resistance
The slanted orientation of the body seat combined with the offset disc design provides the ultimate in check valve performance. The airfoil design of the disc, like the wing on an airplane, offers minimal resistance to flow while lifting and stabilizing in the full open position. Flow characteristics are further improved because the long laying length of the valve body allows water to smoothly enter and pass through without turbulence, eddies or cavitation.

The unbalanced disc weight (heavier below the pivot point) causes the slanting disc to free fall into shut-off position with minimal reverse flow and open with a slight pressure differential. This results in excellent slam resistance combined with lowest head loss.

Off-Set Pivot of Slant Disc Helps Minimize Slam
The off-set pivot of the slant disc provides a distinct advantage. The disc area above the pivot point resists closing because it must close against the reversing water column. This counteracts the closing force to the disc area below the pivot point. The result is no slam or minimal slam depending on how quickly the flow reverses.

To facilitate opening, the seat is at a 55° angle. The 40° travel to optimum open position (15° from horizontal) puts the disc in a stable position. It offers minimum resistance to flow while minimizing water column reversal and slamming on shut down due to the short distance the slanting disc travels to shut-off position.

Self-Centering, 360° Seating Between Disc Ring and Body Seat
APCO CSD Slanting Disc Check Valves close with precise clearance around pivot pins, ensuring self-centering, 360° seating between the concentric disc and body seat rings. These rings are precisely machined and move together or apart with minimum interference, thus eliminating wearing and leakage for many years of service. This movement allows tight seating to meet AWWA C508 standard for metal-to-metal seated valves and virtually eliminates seat maintenance and replacement. The stainless steel pivot pins and bushings are highly wear resistant.

Choice of Body Materials
Body material options include ductile iron, carbon steel and 316 stainless steel. Valve bodies 6″ (150mm) and larger include two accessory openings, and are pre-machined to accept top mounted oil dashpot or bottom mounted buffer for field mounting.

Horizontal or Vertical Flow Up Installation Available
Standard installation is horizontal; contact DeZURIK if vertical flow up is required. Good pump station design encourages at least three pipe diameters of straight pipe downstream of a check valve (in some cases on the upstream side).

Disc Position Indicator
The disc position indicator is standard on valves 6″ (150mm) and larger. The indicator is mounted on the pivot pin cover and provides external indication of disc position. The indicator may be used to trip a micro switch or counting device.

Startup Service Available
DeZURIK factory trained engineers are available for field startup. Field startup services are quoted upon request.


Body Materials: Cast iron, ductile iron, carbon steel or 316 stainless steel

Body Style 800

2 – 72″ (50-1800mm)


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