An automatic valve attached to the lower end of the kelly joint that opens and closes by mud pump pressure. The purpose of the valve is to prevent the mud in the kelly joint from pouring out on the derrick floor each time the kelly is disconnected from the drillpipe. When the mud pump is stopped, the kelly valve automatically closes. After a joint of drillpipe is added to the String and the kelly is made up tight, the pumps are started and the mud pressure opens the kelly valve and drilling resumes. The automatic valve saves valuable mud, keeps the rig floor dry, and speeds up the job of making a connection.
