The flange duckbill valve can effectively prevent the invasion of sea water and sediment. There is a certain density difference between seawater and discharged sewage. When the sewage discharge is small, the traditional outlet diffuser will cause seawater intrusion into the diffuser due to the decrease of jet velocity at the nozzle, and the sediment in the seabed environment will be brought into the diffuser. The outlet of the flange duckbill valve changes with the change of the discharge rate. When the discharge is zero, it can maintain a high jet velocity under the condition of low discharge, so as to prevent the invasion of sea water and environmental sediment.
Flange rubber duckbill valve products are mainly used in waterproof system, drainage system, pump outlet, lifting pump station and submerged aeration system. Main features of the product: rubber flange and valve body are connected into one, which is convenient for installation. The valve body adopts full rubber design, which will not cause silting and jamming, reduces the maintenance cost and allows the solid particles to pass through smoothly.
Flange rubber duckbill valve size standard: Generally speaking, there are two installation sizes in China. One installation dimension is connected with the national standard flange. This is very early when the duckbill valve was designed. In order to match with the national standard, the flange standard of duckbill valve with diameter below 800 was specified. The center distance and outer diameter of flange of 10kg bolt hole in the national standard and the outer diameter of flange were involved in the design of duckbill valve with diameter of more than 800. The other is its own size, which is different from the national standard.
It is made of rubber flange, valve body and duckbill. It is equipped with gasket metal flange. It can be connected with metal flange naturally. It can be directly installed on tank, pipeline and cofferdam. During installation and connection, the size of flange and connecting flange shall be corresponding to each other to ensure the sealing after the connection is tight, and pay attention not to damage the flange lip of rubber blowdown check valve.
The rubber flange is connected with the valve body to facilitate installation. The valve body adopts full rubber design, which will not cause silting and jamming, reduces the maintenance cost and allows the solid particles to pass through smoothly.
1. The flange and pipe assembly of flange duckbill valve shall be checked with tools and methods. The inclination deviation of the cut end face shall not be greater than 1% of the outer diameter of the pipe and shall not exceed 3mm.
2. When assembling flange and pipe of flange duckbill valve, flange angle square should be used to check the verticality of flange.
3. The size of flange gasket should be consistent with the size of flange gasket.
4. The flange of flange duckbill valve shall not be buried in the ground. The flange of buried pipeline or non passing trench pipeline shall be provided with inspection well, and the flange shall not be installed in floor, wall and casing.
5. The flange connection of flange duckbill valve should be concentric with the pipe, and the bolt should be free to penetrate. The flange bolt holes shall be installed in the middle of the span, and the flanges shall be kept parallel, and the deviation shall not be greater than 1.5/1000 of the flange outer diameter, and shall not be greater than 2 mm. It is not allowed to eliminate the skewness by using the method of tightening the bolts with strength.
6. The flange connection of flange duckbill valve should use the same specification of bolts, and the installation direction should be consistent. After the bolts are tightened, they should be close to the flange without any fine seam. When a washer is needed, each bolt shall not be more than one, and the tightened bolt should be flush with the nut. 、
7. When tightening the bolts, the bolts should be symmetrically crossed to ensure that the stress on the gasket is uniform.