Swing check valves and double-disc check valves have their own characteristics. It is not possible to simply judge which one is better. The following is a comparative analysis from multiple aspects:
Structural characteristics
Swing check valve: The valve disc is disc-shaped and rotates around the rotating axis of the valve seat channel. The channel inside the valve is streamlined and has low flow resistance. It is divided into single-disc type, double-disc type and multi-disc type, which are divided according to the valve diameter. The purpose is to prevent the medium from stopping flowing or backflowing and weakening the hydraulic impact.
Double-disc check valve: It consists of two symmetrical semicircular discs. The valve disc opens to both sides under the action of fluid pressure. When closed, the valve disc is pushed closed by spring force or medium pressure.
Performance characteristics
Sealing performance: The sealing performance of the swing check valve is relatively poor, and the sealing performance of the double-disc check valve is better.
Pressure drop: The pressure drop of the swing check valve is large, and the pressure drop of the double-disc check valve is small.
Opening and closing noise: The opening and closing noise of the swing check valve is large, and the opening and closing noise of the double-plate check valve is also large, but it may be slightly better than the swing check valve in some working conditions.
Water hammer effect: The swing check valve has a large impact when closing, which is easy to produce water hammer. The spring-assisted closing of the double-plate check valve can reduce the water hammer effect.
Applicable scenarios
Swing check valve: It is suitable for large-caliber occasions with low flow rate and infrequent flow changes, such as water treatment systems, oil and gas industries, and boiler water supply systems in the power industry, but it is not suitable for pulsating flow.
Double-plate check valve: It is suitable for large-caliber and high-flow occasions, such as municipal water supply systems, seawater desalination equipment, chemical and metallurgical industries, etc., and is also suitable for systems with frequent start and stop.
Installation and maintenance
Installation: The installation position of the swing check valve is not restricted. It can be installed on horizontal, vertical or inclined pipelines. If it is installed on a vertical pipeline, the medium flow direction should be from bottom to top. The double-plate check valve can be installed horizontally or vertically.
Maintenance: The swing check valve has a relatively simple structure and low maintenance cost. The double-plate check valve has a relatively complex structure and high maintenance cost.
In summary, if it is in the case of large diameter, high flow, strict pressure drop requirements and frequent start and stop, the double-plate check valve may be more suitable; if it is in the case of large diameter, low flow rate, infrequent flow changes and not particularly high sealing requirements, the swing check valve may be more suitable.
