| ITEM | COMPONENT | MMATERIAL | QUANTITY |
| 1 | UNION NUT | U-PVC | 1 |
| 2 | END CONNECTOR | U-PVC | 1 |
| 3 | O-RING | EPDM·NBR·FPM | 1 |
| 4 | SPRING | STAUNLESS STEEL | 1 |
| 5 | PISTON | U-PVC | 1 |
| 6 | GASKET | EPDM·NBR·FPM | 1 |
| 7 | BODY | U-PVC | 1 |
| SIZE | NPT | BSPT | BS | ANSI | DIN | JIS | |||
| Thd./in | d1 | d1 | d1 | d1 | D | L | H | ||
| 25mm (1") | 11.5 | 11 | 34 | 33.4 | 32 | 32 | 45.4 | 130 | 69.2 |
| 40mm (1½") | 11.5 | 11 | 48 | 48.25 | 50 | 48 | 61 | 172.2 | 89 |
| 50mm (2") | 11.5 | 11 | 60 | 60.3 | 63 | 60 | 75 | 162.5 | 96.7 |
A detailed description of the check valve:
Check valves are automatic valves, also known as check valves, one-way valves, return valves or isolation valves. The movement of the disc is divided into lift type and swing type. The lift check valve is similar in structure to the shut-off valve, but lacks the valve stem that drives the disc. The medium flows in from the inlet end (lower side) and flows out from the outlet end (upper side). When the inlet pressure is greater than the sum of the weight of the disc and its flow resistance, the valve is opened. On the contrary, the valve is closed when the medium flows back. The swing check valve has a disc that is inclined and can rotate around the axis, and the working principle is similar to that of the lift check valve. The check valve is often used as the bottom valve of the pumping device to prevent the backflow of water. The combination of check valve and stop valve can play the role of safety isolation. The disadvantage is that the resistance is large and the sealing performance is poor when closed.