Abstract: The present invention is directed to a technique of purging unwanted particles from the interior of a valve body. Inlet and outlet ports are formed in the valve housing to allow for circulation of the fluid within the valve body. The flow path of the fluid is isolated from the main fluid flow path when the valve is in the open or closed position. Additionally the pressure of the fluid is at a level higher than that of the main fluid flow.

Abstract: Apparatus and method are provided for selectively firing apparatus in a well when the apparatus is fired by an electrical voltage and produces light upon firing. A photoresistor or other device changes in an electrical property when the light from firing of a section of the apparatus impinges on the photoresistor or other electronic device. The change in electrical property shifts the state of a relay such that the following section of the device can be fired with a voltage of the opposite polarity to that used in firing the preceding section. A test and resetting apparatus for the select-fire apparatus is also provided.

Abstract: Apparatus is provided for cutting a conduit passing through a valve as the valve is closed. The apparatus may be used in subsea well operations or as a safety valve in any well. A spherical outside surface on a cutter element seats in the apparatus. The cutter element cuts a conduit passing through the apparatus in one location and leaves free the severed pieces of the conduit. An actuator to rotate the cutter element may be driven by energy stored in springs or by hydraulic pressure.

Abstract: A plug for sealing a bore in the wall of a high-pressure fluid container is provided. The plug includes a sloping surface adapted to seal at an edge between surfaces of different diameter. A method for sealing the bore by forming a socket in the wall that is adapted to receive the plug is provided. The socket may be formed by reaming a tapered hole to form a surface having a minimum diameter greater than the diameter of the bore and tapping a segment of the tapered hole. A ball may be forced into a cup of the plug to increase radial force between the plug and the socket.