APCO Swing Check Valves have been successfully installed in clean and dirty applications including sewage treatment, water treatment, water distribution, mining, industrial water and wastewater services.
Check Valves are used to allow flow through a pipeline in one direction and prevent flow (check) from returning in the opposite direction. Check valves are commonly installed on the discharge side of the pump. The most important role of a check valve is to act as the automatic shut off valve when the pump stops to prevent draining of the system. Pressure Surge (Water Hammer) can be greatly controlled by selecting the correct check valve.
DeZURIK offers many types of check valves to handle different applications and decades of experience in proper application. Proper valve selection is critical for proper valve performance. With major factories in the United States, check valves can be ordered to meet the latest AIS, BAA, BABA or other requirements. CAD drawings in 46 different file format's can be downloaded to prepare piping layouts. DeZURIK factory trained representatives and application engineers can assist you in sizing and selecting the correct check valve for your application. Contact Us today!
SmartCHECK Pump Control Valves have an integrated swing check and electric motor operator combines the functionality of a full-featured pump control valve with the best features of APCO&#;s CVS- swing check valve. It is the valve you need when you want to control pressure surge during pump startup and shutdown, and close when the pump stops - even during a power outage.
APCO Swing Check Valves prevent back flow of fluid by closing before flow reversal, thereby preventing slam and water hammer These industrial swing check valve designs meet or exceed the current revision of AWWA standard C508.
Double Door Check Valves automatically prevent back-flow and slam. They have a cost-efficient design, short laying length, low weight are easy to install.
Rubber Flapper Swing Check Valves feature a unique, simple design with only one moving part. The flapper opens to a straight unobstructed flow passage. Because the seat is on a 45° angle, the flapper travels only 35° from open to closed, usually before column reversal can occur. It has non-slam characteristics, requires no regular maintenance, and can be installed either horizontal or vertical flow up installation.
Silent Check Valves prevent water hammer by positively closing before reversal of flow can occur. The valve closes silently, is low in cost, reliable and requires no regular maintenance. Silent Check Valves are commonly used in vertical turbine pump installations when pumping from a well to an elevated reservoir. They are also recommended for commercial and industrial HVAC applications such as heating systems and condensate return lines.
Slanting Disk Check Valves are ruggedly designed with superior flow characteristics, minimal head loss and maximum slam resistance. Slanting disc check valves are the most reliable and efficient check valves available. They are ideally suited for clean municipal/industrial water and other industrial liquid applications.
Full Flow Foot Valves can be installed at the bottom of a pump suction line, inside the wet well. Foot valves are an inexpensive way to maintain prime on a single centrifugal pump. APCO Full Flow Foot Valves designed to have the high quality, long wearing construction necessary for valves that are continually submerged in a wet well that are not readily accessible for inspection or repair.
Full Flow Rubber Flapper Foot Valves are designed for water or sewage, and are suitable for submerged service. The Rubber Flapper Foot Valve is installed in the vertical position with the direction of flow in the upward direction. In this position the Foot Valve is normally closed. The Foot Valve opens while the centrifugal pump is running and closes when the pump stops running to maintain a flooded suction and primed pump.
Custom Fabricated Check Valves &#; DeZURIK&#;s Hilton brand Check Valves include a wide variety of custom designed valves for specific applications including Angle Disc Check Valves, Wafer Swing Check Valves, Titling Disc Check Valve, and Fabricated Swing Check Valves.
Pump station valve selection can present a challenge to the Engineer and Owner. For more information on Pump Station applications, see our Pump Stations page.
A check valve allows liquids to flow in one direction only. The primary purpose of a check valve is to prevent water, or other fluids, from backflowing. The check valve closes before flow reversal to prevent slam and water hammer from potentially damaging process equipment.
A check valve is a part of a flow control system that only allows fluids to flow in one direction. When liquid attempts to flow back through the pipe, the valve shuts to prevent backflow. Check valves are often called nonreturn valves because they prevent liquids from returning to their source.
DeZURIK&#;s APCO check valves are essential to the safe and effective functioning of any industrial pump.
When selecting a check valve, the type of fluid and the orientation of the valve are important considerations. Some check valves are suitable for clean water or other fluids, while other check valves valves are better equipped to transport sludge or other viscous liquids. The design orientation is also important since some check valves are designed specifically for veritical or horizontal service while other check valves are designed to accommodate both installation orientations.
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DeZURIK offers a wide variety of valves, actuators and accessories for many applications.
The slanted seat check valve also offers enhanced resistance to water hammer. The valve has a double eccentric shaft position as well as an increased seating angle. This yields a shorter valve stroke, thus reducing the time taken for the door to close.
Hydraulic dampers are recommended, especially when the valves are installed on a pumping station where high frequency opening and closing of the valve is required. The valve disc closes quickly over the first 85% of its angular travel before meeting the hydraulic damper. The damper then dissipates the kinetic energy of the disc and forces it to open slightly. The disc closes until it contacts the damper again and this cushions the disc until it returns to its fully closed position, sealing the valve. This function greatly reduces the onset of water hammer due to the damped and controlled method of valve closure.Hydraulic dampers are recommended, especially when the valves are installed on a pumping station where high frequency opening and closing of the valve is required. The valve disc closes quickly over the first 85% of its angular travel before meeting the hydraulic damper. The damper then dissipates the kinetic energy of the disc and forces it to open slightly. The disc closes until it contacts the damper again and this cushions the disc until it returns to its fully closed position, sealing the valve. This function greatly reduces the onset of water hammer due to the damped and controlled method of valve closure.
For more details, please see our slanted seat check valve product information.
Nozzle check valves are designed with the valve disc connected to the stem which is guided on the central horizontal axis. A spring is positioned between the disc and the diffuser sleeve. When flow enters the valve, the hydraulic force exerted onto the front face reacts against the spring, causing the spring to compress and allow the valve to open. When the flow stops, the spring forces the disc to return to the closed position.
Due to the spring-assisted closure and the short linear valve stroke, the nozzle check valve is one of the quickest acting check valves available and is commonly used in pumped systems where water hammer is a potential concern. Because the disc is constantly in the direct line of flow, the head loss characteristics of this valve are higher compared to that of conventional swing check valves.
For more details, please see our nozzle check valve product information.
In order to choose the right check valve for your application, several selection criteria should be considered. First, however, there is not one type of check valves being the best choice for all applications, and the selection criteria may not be equally important for all cases. Some of the things you may need to consider are fluid compatibility, flow characteristics, head loss, non-slam characteristics and total cost of ownership.
All check valves referred to in this article are designed for water and treated wastewater applications, but using the valves for raw wastewater/sewage applications may cause some issues. When selecting a valve for these fluids, you should consider how the presence of solids may potentially affect operation of the valve.
If a check valve closes very fast, it may prevent slamming against upstream equipment such as pumps. However, the rapid closure will not protect against the surges caused by pumps being started and shut down. If the valve opens (and closes) quickly, the flow will change rapidly and thus increase likeliness of surge occurrence.
Head loss is, among other things, a function of fluid velocity. The head loss through a valve is determined by the internal design of the valve and the opening degree. When a valve is designed with a restricted (narrowed) opening compared to the pipeline, the velocity will increase through the valve, increasing the head loss as a result. Vice versa, if a valve is designed with less restriction and bore is equal size to the pipeline, the head loss will be smaller, and the valve will in practice not affect the overall head loss of the system. There are a number of values for head loss, amongst others zeta values, Kv and Kvs values.
The costs for your check valve consist of more than just the purchase price. For some installations, the most important costs may be purchasing and installation, but in other cases, maintenance or energy costs may be equally or even more important. Also protecting more valuable equipment such as e.g. pumps has to be considered, and looking at the valve performance will be crucial. When considering costs as a selection criterion for your check valve, the total costs over the life of the valve should be considered. In general, the simpler the valve construction is, the lower are the maintenance requirements. The higher the Kv value, the lower the energy consumption. The higher the performance, the better the protection ability.
Check valve slam can affect pressure surges in a negative way. First step of the process is when the pump stops, starting the pressure surge. Second step is, when the flow is reversed, slamming against the fully closed check valve. If the check valve closes too fast, the kinetic energy is turned into high pressure, stressing the pipes, and causing high noise.
A slam sounds like if the disc or the ball from the check valve is hitting the seat and can make quite some noise. However, the sound is not caused by the physical closing but by a sound wave arising from a pressure spike stretching the pipe wall.
To prevent the occurrence of check valve slam, the valve should close in a controlled way and slower when near closed position. For a check valve to close slowly, it requires additional ancillary equipment, such as hydraulic dampers, which act as a cushion to the valve door, as it comes into its seated position. This slower closure allows the fluid to pass through the check valve until it closes, causing less kinetic energy turning into high pressure, and thus less energy to feed and maintain the surge. Consideration must be given to the upstream pump to ensure that it is suitable for reverse spin and flow.
As swing check valves have the disc in the flow stream, helping with rapid closure, they have better non-slam characteristics. However, today many pumps are frequency converted, enabling them to adjust the start-up and closure time to avoid water hammer.
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