The role of check valves in water lines
Introduction
Check valves are extensively used in water pipe systems. The main purpose of installing a check valve on the water pump outlet pipe is to help a large quantum of pressurized water in the pipe from flowing back when the pump is suddenly stopped.
What are check valves?
A check valve is a common valve whose main function is to help the fluid from flowing back in the channel, thereby icing the one- way inflow of the fluid. Check valves are generally installed in fluid channels similar as water pipes, oil painting pipes, and gas pipes to insure that the fluid doesn’t flow back, icing the normal operation of the channel and the safe operation of the outfit.
The structure of the check valve is fairly simple, generally conforming of a valve body and a valve disc. The valve disc can be globular, slice- shaped or conical. When the inflow direction of the medium changes, the valve slice will be pushed by the pressure of the medium and closed.
Operations of check valves
In the water force system, the check valve can help the sewage in the water force pipe from flowing back into the drinking water, icing the safety of drinking water.
In the chemical assiduity, the check valve can help the backflow of dangerous chemicals, icing the safety of product outfit and labor force.
In the oil painting and gas channel, the check valve can help the backflow of oil painting and gas, guarding the ecological terrain and public safety.
How do check valves work?
The working principle of the check valve is to achieve automatic opening and ending by counting on the weight of the opening and ending corridor and the medium pressure. When the medium flows in from the bay end, the valve delirium is pushed open under the action of the medium pressure, and the medium can flow; when the medium flows back, the valve delirium is closed under the binary action of its own weight and the pressure of the backflow medium to help the medium from flowing back.
In the water force and drainage systems of domestic and marketable structures, lift check valves are frequently used for drainage branches in areas similar as bathrooms and kitchens. These pipes are generally small in periphery and have high conditions for sealing. Lift check valves can effectively help sewage backflow and insure the hygiene of the inner terrain.
In large-periphery pipes similar as water diversion pipes and drainage pipes in hydropower stations, swing check valves can help water from flowing back and cover the safe operation of outfit similar as turbine creator sets.
In the water force and drainage bimahs of high- rise structures, due to limited space, butterfly check valves are extensively used due to their compact structure and can effectively help water backflow.
In channels that transport sharp media, similar as channels for transporting chemical raw accoutrements similar as sulfuric acid and hydrochloric acid, diaphragm check valves can insure that the media doesn’t blunder, cover channels and outfit from erosion, and insure the safety and stability of the product process.
Types of check valves
Swing check valve: The disc of this check valve rotates around the leg to open and close. In the completely open state, the fluid pressure is nearly disencumbered, so the pressure drop through the valve is fairly small. Swing check valves are suitable for larger compasses, advanced pressures (can also be used in vacuum systems) and larger overflows.
Lift check valve: The disc of this check valve slides along the perpendicular centerline of the valve body. Lift check valves can only be installed on vertical pipes, and the slice on high- pressure small- periphery check valves can be a ball.
Wafer check valve: Wafer check valves are generally installed between two flanges and fixed by bolts. They’ve a compact structure and are easy to install. This check valve is generally used in small and medium- sized channel systems.
Silent check valve: Silent check valves are designed to reduce the noise generated when fluid overflows back. This valve is generally used in places where a quiet terrain is needed, similar as hospitals, seminaries, etc.
Ball check valve: The disc of the ball check valve is a sphere or semicircle, which is opened or closed by the force of the medium. This valve is generally used for small- periphery pipes or small artificial operations.
Slow- ending check valve: The slow- ending check valve has a detention point during the ending process, which can reduce the circumstance of water hammer. This valve is frequently used in systems that need to control fluid impact.
Check valve selection criteria
The following factors need to be considered when choosing a suitable check valve:
1.Fluid parcels The selection of check valves should be determined grounded on the parcels of the fluid. Different fluids have different conditions for valve accoutrements and sealing.
2.Working pressure Determine the needed valve rated pressure grounded on the system’s working pressure.
3.Flow conditions elect the applicable valve type and size grounded on the system’s inflow conditions.
4.Temperature conditions elect the applicable valve material grounded on the system’s operating temperature to insure that the valve can operate typically in high or low temperature surroundings.
5.Installation conditions elect the applicable valve connection system grounded on the system’s installation conditions, similar as flange connection, threaded connection or welding connection.
6.profitable effectiveness elect a suitable check valve grounded on budget and profitable considerations, taking into account factors similar as valve price, conservation cost and life.
In general, choosing a suitable check valve requires comprehensive consideration of the below factors and making trade- offs and opinions grounded on specific operation conditions.