type valves where the water flow is non uniform to further prevent water hammer or sudden pressure buildup upstream of the valve housing 40 the closing of the in line valve member 28 is restrained by an adjustable damping member 22 disposed between the underside of the guide member 18 and the adjustable nut 25 mounted on the tube 20 in the preferred embodiment adjustable damping member 22 is a helical spring disposed as shown with one end of the spring in engagement with the underside of the guide member 18 and the other end resting on the upper side of the nut 25 other types of damping devices such as a tubular body 52 filled with a viscous fluid 54 as illustrated in fig3 can be disposed about the tube 20 to provide a damping action on the upward movement of the in line valve 28 in the event that hydrant 10 is accidentally removed adjustment of the damping action is advantageously effected by adjusting the nut 25 to increase or decrease the resistance to movement of the tube 20 through the opening 13 provided in the guide member or plate 18 and consequent movement of the in line valve member 28 upwardly towards the valve seat 46 normally the damping device will be under no compression in.