is in the closed position more specifically the seal 20 ensures that the flapper 16 when closed will form a fluid tight interface with the housing 14 such seals are common and tend to be relatively soft this makes them vulnerable to flow cutting and hence they require protection protection in the illustrated configuration is provided by a flow tube that need be only long enough to extend past the seal 20 when the flapper 16 is open this is illustrated in fig2 further one of ordinary skill in the art will recognize that as illustrated the flow tube would not function to open the flapper 16 as is the case in many prior art valves but rather stops short of interacting physically with the flapper 16 in this configuration it is the flow of injection fluid that opens and maintains the flapper 16 in the open position the flow tube in this configuration then has only to protect the seal 20 which it does in the position illustrated in fig2 it is noted that it is possible to apply the concepts herein to a valve with a longer flow tube that also has function to open the flapper 16 but such function is not necessary to the teaching herein in either case an extension spring 22 in operable communication with the flow tube 12 and the housing 14 will automatically move the flow tube 12 to the operational position when the flapper 16 is opened that opening being due solely to flow or to.