APCO CHECK VALVE GUIDE Rubber Flapper Swing Check Valve Series 100 Silent Check Valves Series 600 Globe Style Series 300 Wafer Style Slanting Disc Check Valve Series 800 Automatic Control Check Valve Series 8000 Double Door Check Valve Series 9000 Cushioned Swing Check Valves Series 6000 Series 6000B Series 6100

Which Check Valve Should I Use? Check valves are available in numerous types, styles and shapes. Generally a valve manufacturer builds only one type of check valve. DeZURIK/APCO builds seven types and twenty styles. Therefore, we offer the consulting engineer open, objective and unbiased information about a broad range of check valves and their proper selection and application. The purpose of this brochure is to collect and condense the many desirable features of the most common type checks into a single source. With a single source of information, we hope not only to simplify the design engineer’s...

Check Valve Comparisons Swing Check (Single Disc) Swing Check closure is affected by gravity (weight of disc) and reverse flow. The pivot point of the Swing Check is outside the periphery of the disc and the greater the head, the greater the possibility that the fluid will flow back through the valve before the disc can be shut off. Use caution applying this type of check valve where reverse flow velocities are high. (See APCO Cushioned Swing or Controlled Closing Check Valves) Conventional swing check valve disc closes through a long 70° to 90° arc. With reverse flow started, shutoff characteristics...

Check Valve Comparisons Slanting Disc Check (Pivot Off Center) Figure 4 Slanting Disc Check is a unique valve (Fig. 4). The main body is made of two pieces to allow a greatly enlarged flow area through the disc and seat section. The disc pivots off center with approximately 30% of the disc area above the pivot point to offer resistance against the 70% disc area below the pivot point. Hence, this type check has built in non-slam shut off characteristics. The seating angle is 55°. The disc swings open through this 55° seat angle, traveling a short distance stopping at 15° off the horizontal. Hence,...

APCO Swing Check Valve Features The Cushioned Swing Check Valve is a heavily constructed, full ported cushioned closure valve, constructed to meet A.W.W.A. standards. The cushioning device is an external cylinder which fills with air when the valve opens. When closing, the piston is driven downwards rapidly to compress the air trapped in the cylinder resulting in cushioned closing. The Cushioned Swing Check Valve is air cushioned for fast closing applications. For slow closing applications, oil control is recommended. All internals including the seat in the body can be removed through the bonnet...

APCO Double Door Check Valve Double Door Check Valves are extremely short in length, i.e. a 12" Double Door Check is 71/8 inches in length (a 12" conventional check is 28" in length) resulting in considerable material and labor savings. Therefore, this type check valve costs less per inch of size than most other types of check valves available. Although this valve is light in weight it is capable of heavy duty, continuous operation. The operational principle of the valve is the same as the ordinary outside lever and spring swing check valve, with the exception that the Double Door Check Disc...

APCO Rubber Flapper Swing Check Valve The Rubber Flapper Swing Check is uniquely simple in design. It has one moving part and the flapper does not pivot on a hinge pin, rather it flexes to open. This check valve is non-slamming in design because the flapper only travels 35° to reach the 45° seat. Since the flapper is spring loaded (due to resiliency) it usually closes before flow reversal or near zero velocity. The Rubber Flapper Check is virtually maintenance free. The flapper has been flex tested equivalent to 20 years of field service without fatigue. The Rubber Flapper Check was flow tested...

APCO Slanting Disc Check Valve The Slanting Disc Check Valve is the most reliable swing type check valve available today. The pivot point of the disc is off center which sets it apart from other swing checks. The offset pivot point is unique and is one reason for the non-slam characteristics of the valve. The disc area above the pivot point counteracts the disc area below the pivot point, therefore, when the disc closes it should not slam. The split body design creates a 42% greater area through the disc section than the equivalent pipe area, hence, it has the lowest head loss compared to any...

APCO Automatic Control Check Valve The Automatic Control Check Valve is not a conventional type check valve. It is four valves in one. This automatic check is suitable where Pump Discharge Control is essential due to high velocities or on pipelines exceeding a mile in length. This valve is electric motor controlled. The valve can be directed from a remote control center automatically. The four valve features are: (1) shut off valve, (2) throttle flow valve, (3) controlled closing check valve, (4) drain valve. During operation, should power failure occur, the valve will automatically shut off...

APCO Silent Check Valves The Wafer Style Silent Check Valve utilizes the same features as the Globe Style Silent Check within a compact wafer style body. Wafer Style Silent Checks are commonly specified for use in the H.V.A.C. field where silent operation is essential. They are not generally used in the municipal field because of their higher head loss. Use Wafer Style Silent Check where space savings in the pump house is the primary concern. The globe style is the most popular. Silent Check Valves are fast closing. This type of check valve can be installed in any position, flow up or flow down....

Dynamic Performance Of Check Valves The head (pressure) rise in a pipe due to an incremental change in velocity is calculated using the following equation: H = transient head (pressure) rise, ft (m) a = wave speed, ft/s (m/sec) equation 1 V = change in velocity, ft/sec (m/sec ) g = gravity, 32.2 ft/sec2 (9.81 m/sec2) The transient head rise is directly proportional to the wave speed (equation 1). Wave speed is a parameter that must be accurately evaluated for each pumping system. After a sudden change in velocity, a pressure wave travels between two arbitrary points in a pipe in the time it takes...