Control valve

A valve system, comprising:

• a valve, comprising:
• a flow passage;
• a slab gate disposed in the flow passage, wherein the slab gate is configured to adjust a fluid flow through the flow passage;
• a first multi-stage throttling section disposed in the flow passage on a first side of the slab gate, wherein the multi-stage throttling section comprises a plurality of throttling plates arranged in a stack one after another in a flow direction through the flow passage, a first plate in the stack comprises a first material that is resistant to wear, a second plate in the stack comprises a second material that is resistant to cracking, the second plate is configured to catch at least a portion of the first plate in the event of failure of the first plate;
• a first sealing insert configured to seal a first surface of the slab gate with a mating surface of the first multi-stage throttling section, wherein the first sealing insert is separate from the slab gate and the multi-stage throttling section, and the first sealing insert is configured to block direct exposure of the first surface to the fluid flow while the slab gate is disposed in an open position;
• and
• wherein the second plate comprises a plurality of second openings that are larger than a plurality of first openings in the first plate, and the second plate has a greater thickness than the first plate.

A fluid system, comprising:

• a valve, comprising:
• a flow passage
• a lateral passage that intersects the flow passage;
• a slab gate disposed along the flow passage;
• and
• a multi-stage throttling section;
• disposed along the flow passage on one side of the slab gate, wherein the slab gate and the multi-stage throttling section are both accessible via the lateral passage, and the multi-stage throttling section comprises:
• a first throttling disc comprising a first plurality of openings;
• a second throttling disc comprising a second plurality of openings, wherein the first throttling disc comprises a first material that is resistant to wear, the second throttling disc comprises a second material that is resistant to cracking, and the second throttling disc is configured to catch at least a portion of the first throttling disc in the event of failure of the first throttling disc;
• a seat ring extending around a perimeter of the first throttling disc, wherein the seat ring extends at least partially into the lateral passage;
• and
• wherein the second plurality of openings comprises larger openings than the first plurality of openings, and the second throttling disc has a greater thickness than the first throttling disc.