Equalizer valve

An apparatus for sealing a fluid flow, the apparatus comprising:

• a seal cartridge having a first opening, a second opening, and a fluid path extending from the first opening to the second opening;
• a spring having a support end and a seal end, wherein the support end is supported by the seal cartridge, and wherein the spring extends into the fluid path;
• a seal member coupled to the seal end of the spring;
• and
• wherein the seal member is reciprocally disposed adjacent the second opening between an open position and a closed position, and wherein the seal member seals the second opening from the fluid path in the closed position.

An apparatus for testing a subterranean earthen formation, the apparatus comprising:

• a cylindrical tool housing;
• a formation probe assembly supported by the housing;
• a valve supported by the housing, the valve comprising:
• a seal cartridge comprising:
• a housing having a first opening, a second opening, and a fluid path extending from the first opening to the second opening;
• a spring having a support end and a seal end, wherein the support end is supported by the housing, and wherein the spring extends into the fluid path;
• a seal member coupled to the seal end of the spring;
• and
• wherein the seal member is reciprocally disposed adjacent the second opening between an open position and a closed position, and wherein the seal member seals the second opening from the fluid path in the closed position;
• and
• a means for actuating the seal member between the open and closed positions;
• a fluid port extending through the housing from the valve to the probe assembly;
• and
• wherein the fluid port and the fluid path are in fluid communication when the seal member is in the open position, and the fluid port is sealed from the fluid path when the seal member is in the closed position.

A method for sealing a fluid flow, the method comprising:

• directing a fluid flow through a seal cartridge;
• supporting a spring such that the spring extends into the fluid flow;
• pre-loading a seal member using the spring;
• and
• actuating the seal member between an open position and a closed position, wherein the fluid is allowed to flow through the seal cartridge when the seal member is in the open position and the fluid is sealed when the seal member is in the closed position.

A method of testing a subterranean earthen formation, the method comprising:

• directing a fluid flow through a tool string, through a seal cartridge and a fluid port, and adjacent a formation probe assembly having a probe, the seal cartridge and formation probe assembly being supported by the tool string;
• supporting a spring in the seal cartridge such that the spring extends into the fluid flow;
• pre-loading a seal member using the spring;
• actuating the seal member from an open position relative to the fluid port to a closed position relative to the fluid port;
• and
• sealing the fluid flow from the fluid port and the formation probe assembly.