A rubber line check valve, also known as a duckbill valve or rubber flap valve, is a type of check valve that is commonly used in applications where the flow of fluids or gases needs to be regulated in one direction.

The valve is made of flexible rubber material and is designed to allow flow in one direction while preventing backflow or reverse flow. It consists of a conical or flat rubber sleeve or flaps that act as a one-way door. When the pressure on the upstream side of the valve is greater than the pressure on the downstream side, the valve opens, allowing fluid or gas to flow through. When the pressure on the downstream side becomes greater than the upstream side, the valve closes, preventing backflow.

Rubber line check valves are often used in various industries, including wastewater treatment, sewage systems, drainage systems, irrigation systems, and industrial piping systems. They are preferred in applications where a tight seal is required, as the rubber material provides excellent sealing properties.

These valves are typically easy to install and require minimal maintenance. However, it is important to select the appropriate size and material of the valve based on the specific application requirements.

NO.	Part	Material	Code
1	Alignment Body	Nodular Cast Iron	GGG40.3
2	Insert Body	Nodular Cast Iron	GGG40.3
3	Set Screw	Steel	-
4	Liner	NBR/EPDM	-
5	Spring	Stainless Steel	SS304/SS316
6	Plate	Aluminium Bronze alloy	C954
7	Shaft	Stainless Steel	SS316
8	Shaft Plug	Stainless Steel	SS316
9	Thrust Washer	Teflon	-

Size	A	B	C	D	E	F(PN10/PN16)	G(PN10/PN16)	H	」	K	Weight(kg
DN50	159	101	84.8	66.7	50	125	18	28.5	47.6	54	2.27
DN65	179	120	99	79.4	50	145	18	36.5	58.7	54	2.72
DN80	200	133	116	92.1	50	160	18	41.3	69.9	54	3.63
DN100	220	171	143	118	60	180	18	54	87.3	63.5	6.81
DN125	250	198	172	144	63	210	18	67.5	113	66.7	9.08
DN150	285	222	201	172	75.5	240	22	80.2	141	79.4	11.8
DN200	340	280	255	222	94.5	295	22	106	192	98.4	19.52
DN250	406	336	309	276	97.5	350/355	22/26	130	230	102	26.33
DN300	482	406	366	327	126	400/410	22/26	159	275	130	45.4
DN350	533	450	394	356	176	460/470	22/26	172	305	181	60.29
DN400	596	488	488	406	158	515/525	26/30	197	356	162	77.18
DN450	635	545	506	460	180	565/585	26/30	222	406	184	99.88
DN500	715	595	553	508	211	620/650	26/33	248	460	216	130.3