| 摘要 |
A check valve includes a seal 60, a dart 64 having a closed head 62, sealable against the seal, one or more flutes 63 on the dart, and a spring 50 applying a biasing force to the dart to a sealing position, that force being capable of being overcome by a fluid pressure acting in a direction opposing the spring force. The check valve can be used in a safety valve with a chemical injection configuration (20, fig 1). The safety valve can include a hydraulic fluid pressure operated piston (12, fig 1) at the housing. The device further includes a flow tube (18, fig 1) in operable communication with the piston (12, fig 1) and a chemical injection configuration (20, fig 1) disposed within the housing. |
