A safety valve in combination with a resilient tube for preventing the free flow of fluid through the resilient tube comprises a valve body which is connected to a valve head of generally circular cross-section which is formed with a flat peripheral land. The resilient tube is disposed over the valve head for snug fluid-sealing engagement between the inner surface of the tube and the flat land on the valve head.Safety Valves Also, the resilient tube is fluid sealed to the valve body for fluid communication therebetween. Stretching the resilient tube separates a portion of the inner surface of the tube from the flat land on the valve head to permit fluid flow past the valve head. When the resilient tube is unstretched, the engagement between the inner surface of the tube and the flat land of the valve head prevents free fluid flow.Globe Valves A valve system for use in a subterranean well, the valve having multiple closure devices, or a closure device and a device for protecting the closure device.GATE VALVES A valve system includes a valve with a closure assembly. The closure assembly has a closure device and a protective device which alters fluid flow through a flow passage of the valve prior to closure of the closure device to thereby protect the closure device. A safety valve system includes a safety valve with a closure assembly having at least two closure devices arranged in series for controlling flow through a flow passage of the safety valve. Another safety valve system includes a safety valve assembly including multiple safety valves arranged in parallel. One portion of fluid from a fluid source flows through one of the safety valves, while another portion of fluid from the fluid source flows through another safety valve.

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