APCO CVS-6000 Swing Check Valve Lever and Weight

Swing check valve with a choice of closure control for pump lines

The APCO CVS-6000 swing check valve is made by DeZURIK for clean and dirty services, including water, sewage and a wide range of industrial uses. The bulletin describes heavy-duty construction with a full waterway flow area, which gives low head loss and inherent slam minimization at elevated flow rates and high pressures.

Two body styles are offered. The 6000D meets AWWA C508-25 and accepts lever and weight, lever and spring, air-cushioned cylinder and oil-cushion closure control. The 6000A/6000 body adds oil-controlled closure with either a side-mounted cylinder or a bottom-mounted buffer whose closing time is adjustable within system limits, designed to decelerate reverse flow gradually after pump shutdown.

CVS-6000 technical specification

Closure control options explained

Lever and weight is the economical choice for gradual flow reversal, and the position of the weight sets the closing speed. Lever and spring closes faster for sudden reversal but costs some head loss, since the pump must overcome the spring force. The air-cushion cylinder suits free-open, fast-close duty: a weighted lever drives a piston into a closed chamber, and an adjustable control valve sets the cushion.

The oil cushion uses a precision shock absorber bracket on the valve side that works with the lever and weight to absorb the counterweight energy, with three-stage closing and a timing valve on smaller sizes. These adjustments let the closing time be tuned on site to match the surge analysis.

Three-stage and buffer closure on the 6000A/6000 body

For free-open, slow-close duty the side-mounted oil cylinder (OC, 2 to 20 in) gives three independently adjustable closing stages: a timing valve first allows very fast closure to any degree, a flow control valve then varies the speed toward final closure, and an internal cylinder adjustment controls the last part of travel to shutoff. This cuts the volume of backflow that occurs with two-stage devices. The oil reservoir must be mounted vertically regardless of valve position, so the mounting position is specified at ordering.

The bottom-mounted buffer (BMB, 6 to 66 in) lets the disc open freely and close freely for about 90 percent of its stroke; the oil buffer then meets the disc and controls the final 10 percent through a color-coded micrometer valve with a locking set screw. It is recommended for larger valves, vertical upward flow and surge cases where reversal after a hydro-pneumatic tank or open discharge is instantaneous.

Seat design and maintenance

The 6000D combines a precision-machined contoured metallic body seat with a self-aligning molded elastomer disc seat (patent pending), which removes the articulated disc-to-arm joint. A built-in seat compression limiter stops the disc from squeezing the rubber past its elastic limit.

Top entry means every internal part, including the body seat, can be replaced in the field by removing the cover, without taking the valve out of the pipeline and without special tools. Order options cover AIS, Build America Buy America for LW, LS and AC devices, NSF approval, a certified hydrostatic test report (DTR), vertical flow up (VP) and stainless bolting (SB16).

Ordering, applications and documents

The printed order example is CVS,16,6000D,F1,DI,DI-S2-S2-NBR*OB,SEL22: a 16 in 6000D with ductile iron body and disc, 316 shaft and seat, NBR disc seat, oil cushion and a DPDT limit switch. As general engineering context, such valves sit on pump discharge lines in water transmission, irrigation, desalination and sewage pumping stations in the Gulf.

Find related valves under Check Valves. Bulletin 6000 (07/2026) is attached with Cv tables, weights and materials; send size, body style, closure control, seat and accessories when requesting a quotation from Seven Star LLC.

Using the CVS-6000 in Oman and the GCC

Swing check valves with controlled closure are used in the region’s water transmission pumping stations, sewage pumping stations, desalination plant product water pumps and industrial cooling water systems. Long pipelines and high-head pumps are common in the region, and these conditions make water hammer and check valve slam a real risk, which is why the closure control options matter.

The right closure option depends on the pumping system, including pipeline length, static head, pump inertia and the number of pumps in parallel. A surge analysis, where available, helps decide whether lever and weight, an air cushion or an oil-controlled closure is needed and how the closing time should be set. In sewage service, choose a configuration suited to solids, and plan regular checks of the closure control settings.

Information to send with an enquiry

• Size, pressure class and flange standard
• Fluid: water, sewage or industrial liquid
• Closure control option and any surge analysis
• Pump data and pipeline length where available
• Quantity