Stop seal for application of high temperature and high pressure

A stop seal for application of high temperature and high pressure, which the stop seal is adapted for installation between a column-shaped pump shaft and a housing surrounding the pump shaft and spaced apart from the pump shaft at a predetermined interval to have a gap between the pump shaft and the housing, comprising:

• a first seal member as an assembly of operating on the fluid of high temperature and high pressure, which is made of a shape memory alloy material, and is deformed when the fluid of high temperature is introduced to be moved in a direction adjacent to the pump shaft;
• a second seal member which has one side fixed to the housing and an opposite side which is movable between a first position spaced apart from the pump shaft and a second position in contact with the pump shaft to seal the gap, and is made of a synthetic resin material;
• and
• a third seal member made of a metal material which has one side fixed to the housing and an opposite side which is moved between a third position spaced apart from the pump shaft and a fourth position coming into contact with the pump shaft to block the gap, and is moved from the third position to the fourth position by the second seal member elastically deformed by a differential pressure to seal the gap when the differential pressure is generated before and after the second seal member after the second seal member blocks the gap,
• wherein when the fluid of high temperature and high pressure is introduced and the first seal member is moved in the direction adjacent to the pump shaft, the opposite side of the second seal member is moved from the first position to the second position by the first seal member to block the gap between the pump shaft and the housing, thereby preventing the fluid of high temperature and high pressure from leaking into the atmospheric space.