| 摘要 |
<p>A liquid level sensing apparatus (32) senses the level of liquid surrounding the apparatus. A plurality of axially spaced sensors (36) are enclosed in a separator tube (86). The separator tube (86) tends to collapse the level of a two-phase fluid within the separator tube into essentially a liquid phase and a gaseous phase where the collapsed level bears a relationship to the coolant inventory outside the separator tube. The level of the liquid phase is sensed by level sensing apparatus (32). The separator tube (86) contains inlet-outlet ports (90,92) near the top and bottom thereof to equalize the liquid level inside and outside the separator tube (86) when the level fluctuates or the water within the separator tube (86) flashes to steam. Each sensor (36) is comprised of a heater (64), a heated thermocouple junction (68) and an unheated thermocouple junction (66) within an elongated heat conductive housing (62). The heated portion of housing (62) is enclosed in a splash guard (72) with inlet-outlet ports ( 78,82) near the top and bottom to equalize the liquid level inside and outside the splash guard (72) and to eliminate the spurious indications of liquid level change which may arise if water droplets contact the housing (62) in the region of the heater. To prevent steam bubbles entrained in a two-phase fluid cross flow from entering the lateral inlet-outlet ports (90,92) of the separator tube (86), the separator tube (86) is enclosed in support tube (100) which may in turn be enclosed in an otherwise unused control element assembly shroud (110). The lateral inlet-outlet ports (90,92) of separator tube (86) are axially offset from lateral inlet-outlet ports (102) of support tube 100 at least where support tube 100 is subjected to cross flow. The shroud (110) is open on the bottom and has lateral inlet-outlet ports (112) to facilitate liquid level fluctuations to equalize inside and outside shroud (110). An alternate embodiment permits the measurement of more than one liquid level.</p> |
