How are check valves generally used?
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Under what circumstances is it necessary to install a check valve? How exactly do I install it? Could you send me a specific photo to take a look at?
When backflow is not allowed, a check valve must be installed； Just pay attention to the orientation when installing; it cannot be installed in reverse.
1. Pump outlet, to prevent backflow of material and loss of the pump impeller. 2. Pipes that prevent backflow of material (especially those connecting two different types of material for mixing). 3. Outlets of other equipment, where it is necessary to prevent backflow of material. It is related to the material, but not in a very significant way.
Vertical installation is more reliable than horizontal one; pay attention to the direction.
1. Swing check valve – Installation condition: horizontal or vertical pipe! 2. Lift-type check valve Installation condition: horizontal pipe! 3. Cross-flow check valve Installation conditions: horizontal pipe or vertical pipe!
To prevent damage to the equipment, areas where backflow of fluid can occur, such as the outlet of centrifugal pumps, should not be operated； On the pipes of the two media to prevent backmixing between them.
A check valve is a valve whose opening and closing elements open or close on their own due to the flow of the medium and its pressure, in order to prevent backflow of the medium. Check valves belong to the category of automatic valves; they are primarily used in pipelines where fluid flows in one direction only, allowing the fluid to move in that direction alone in order to prevent accidents. Classified by structure, check valves can be divided into lift-type check valves, swing-type check valves, and butterfly check valves. Lifting check valves can be divided into vertical and horizontal types. Swing check valves are divided into three types: single-disc, double-disc, and multi-disc. Butterfly check valves are of the straight-through type; the aforementioned check valves can be connected in three ways: threaded connection, flange connection, and welding. The following points should be considered when installing check valves: 1. Do not allow the check valve to bear any weight within the pipeline; large check valves should be supported independently so as to remain unaffected by the pressures generated by the piping system. 2. During installation, ensure that the direction of medium flow is consistent with the arrow indicated on the valve body. 3. Lift-type vertical flap check valves should be installed on vertical pipes. 4. Lift-type horizontal disc check valves should be installed on horizontal pipes.
Classification of check valves:
I: Classification by material: (Material of the check valve body)
1. Cast iron check valves.
2. Brass check valves.
3. Stainless steel check valves.
II: Classification by function:
1. NRVZ silent check valves.
2. NRVG silent check valves.
A check valve is a valve that can automatically prevent fluid from flowing in reverse. The valve disc of the check valve opens under the action of fluid pressure, allowing the fluid to flow from the inlet side to the outlet side. When the pressure on the inlet side is lower than that on the outlet side, the valve disc automatically closes under the influence of factors such as the fluid pressure difference and its own gravity to prevent backflow of the fluid. Check valves are generally classified into lift-type, swing-type, butterfly-type, diaphragm-type, and other types. The structure of a lift-type check valve is generally similar to that of a globe valve; its valve disc moves up and down along the channel in a linear manner, offering reliable operation, but it generates significant fluid resistance, making it suitable for applications with small diameters. Lift-type check valves are available in straight-through and vertical types. Straight-through lift check valves can generally only be installed in horizontal pipelines, while vertical lift check valves are usually installed in vertical pipelines. The disc of a swing check valve rotates around an axis. Its fluid resistance is generally lower than that of lift-type check valves, and it is suitable for applications with larger diameters. Globe check valves can be classified into single-disc, double-disc, and multi-disc types based on the number of disc plates. Single-disc swing check valves are generally suitable for applications with medium pipe diameters. When a single-disc swing check valve is used for large-diameter pipelines, in order to reduce water hammer pressure, it is advisable to employ a check valve with a slow-closing mechanism that can mitigate water hammer pressure. Double-disc swing check valves are suitable for large and medium-sized diameter pipelines. The wafer-type double-disc swing check valve is small in size and light in weight; it is a type of check valve that has seen rapid development ； Multi-disc swing check valves are suitable for large-diameter pipelines. The structure of a butterfly check valve is similar to that of a butterfly valve. It has a simple structure, low flow resistance, and low water hammer pressure. Diaphragm check valves come in various structural forms, all of which use a diaphragm as the closing element. Thanks to their excellent performance in preventing water hammer, simple structure, and low cost, they have seen rapid development in recent years. However, the operating temperature and pressure of diaphragm check valves are limited by the diaphragm material. 3. NRVR silent check valve 4. SFCV rubber-disc check valve 5. DDCV double-disc check valve Check valve standards: swing check valve, flue check valve, through-flow check valve, wafer check valve Slow-closing check valve, vertical check valve, silent check valve; check valve prices, low-resistance slow-closing check valve The H76 type wafer double-disc swing check valve has low water hammer pressure, a short valve disc travel distance, and spring-assisted closing, resulting in fast closing speed. The H44 type flange single-disc swing check valve has a large valve disc travel distance and requires a longer time to close; the water hammer pressure of the H76 type is only 1/2 to 1/5 that of the H44 type
I: Classification by material: (Material of the check valve body)
1. Cast iron check valves.
2. Brass check valves.
3. Stainless steel check valves.
II: Classification by function:
1. NRVZ silent check valves.
2. NRVG silent check valves.
A check valve is a valve that can automatically prevent fluid from flowing in reverse. The valve disc of the check valve opens under the action of fluid pressure, allowing the fluid to flow from the inlet side to the outlet side. When the pressure on the inlet side is lower than that on the outlet side, the valve disc automatically closes under the influence of factors such as the fluid pressure difference and its own gravity to prevent backflow of the fluid. Check valves are generally classified into lift-type, swing-type, butterfly-type, diaphragm-type, and other types. The structure of a lift-type check valve is generally similar to that of a globe valve; its valve disc moves up and down along the channel in a linear manner, offering reliable operation, but it generates significant fluid resistance, making it suitable for applications with small diameters. Lift-type check valves are available in straight-through and vertical types. Straight-through lift check valves can generally only be installed in horizontal pipelines, while vertical lift check valves are usually installed in vertical pipelines. The disc of a swing check valve rotates around an axis. Its fluid resistance is generally lower than that of lift-type check valves, and it is suitable for applications with larger diameters. Globe check valves can be classified into single-disc, double-disc, and multi-disc types based on the number of disc plates. Single-disc swing check valves are generally suitable for applications with medium pipe diameters. When a single-disc swing check valve is used for large-diameter pipelines, in order to reduce water hammer pressure, it is advisable to employ a check valve with a slow-closing mechanism that can mitigate water hammer pressure. Double-disc swing check valves are suitable for large and medium-sized diameter pipelines. The wafer-type double-disc swing check valve is small in size and light in weight; it is a type of check valve that has seen rapid development ； Multi-disc swing check valves are suitable for large-diameter pipelines. The structure of a butterfly check valve is similar to that of a butterfly valve. It has a simple structure, low flow resistance, and low water hammer pressure. Diaphragm check valves come in various structural forms, all of which use a diaphragm as the closing element. Thanks to their excellent performance in preventing water hammer, simple structure, and low cost, they have seen rapid development in recent years. However, the operating temperature and pressure of diaphragm check valves are limited by the diaphragm material. 3. NRVR silent check valve 4. SFCV rubber-disc check valve 5. DDCV double-disc check valve Check valve standards: swing check valve, flue check valve, through-flow check valve, wafer check valve Slow-closing check valve, vertical check valve, silent check valve; check valve prices, low-resistance slow-closing check valve The H76 type wafer double-disc swing check valve has low water hammer pressure, a short valve disc travel distance, and spring-assisted closing, resulting in fast closing speed. The H44 type flange single-disc swing check valve has a large valve disc travel distance and requires a longer time to close; the water hammer pressure of the H76 type is only 1/2 to 1/5 that of the H44 type
Check valves must be installed in pipes to prevent backflow, and attention should be paid to the type of valve and its flow direction during installation.