Abstract: A submersible pump includes a pump valve configured to switch the pump between first and second states in which a piston is respectively extended and retracted. The pump valve includes first and second components that reciprocate between corresponding first and second positions. The pump is in the first state when both components are in their corresponding first position. The pump is in the second state when both components are in their corresponding second position. Neither the valve nor the pump is hydraulically locked at any time during normal operation.

Abstract: A detonating device includes a high explosive portion comprising high explosive; a low explosive portion comprising low explosive; and a transition portion between the high explosive portion and the low explosive portion, wherein the transition portion comprises a mixture of high explosive and low explosive.