Thermocouple with out-of-line aspiration holes
AssigneeAmespace, Inc.
InventorRobert A. Pustell
Life of this patent
Estimating the term…
Abstract
The response time of a thermocouple is improved by offsetting the outlet aspiration opening or openings in the thermocouple protective housing from the gas flow axis and the inlet opening. The outlet aspiration opening is located substantially at the gas separation point which is a point of minimum gas pressure. The degree of offset is thus chosen to maximize the pressure differential, .DELTA.P, between the inlet and the outlet openings. This increases the gas flow rate through the housing and past the thermocouple junction thereby substantially improving the thermocouple response time.
Claims33
A thermocouple assembly for measuring the temperature of a fluid stream comprising:
- (a) a casing,
- (b) at least one pair of dissimilar wires disposed in said casing and forming a thermocouple junction,
- (c) insulation dispersed in said casing and separating said dissimilar wires from said casing and from each other,
- (d) a protective housing spaced apart from and surrounding at least a portion of said casing containing a thermocouple junction,
- (e) means to allow a part of the heated stream to flow through said protective housing and past said casing in the area of the thermocouple junction, including:
- (1) an inlet opening in said housing positioned essentially along the flow axis of the stream, said inlet opening in axial alignment with said thermocouple junction, and (2) at least one outlet opening in said housing downstream from the inlet opening to establish a flow path through said housing, and (f) means for increasing the flow rate of the fluid through said housing by locating the outlet opening at a minimum fluid pressure point, thereby maximizing the pressure difference between inlet and outlet openings to provide rapid response of the thermocouple to changes in fluid stream temperature.
A thermocouple assembly for measuring the temperature of a gaseous stream including at least one thermocouple junction positioned in a casing surrounded by a protective housing spaced from said casing,
- (a) means to expose the thermocouple junction in said housing to a gaseous stream including an inlet opening and at least one outlet opening in said housing, the inlet opening and thermocouple junction being axially aligned, (b) said outlet opening being radially offset from the inlet opening, the degree of off-set being chosen to locate the outlet opening in a minimal pressure area on the outside of the housing to maximize the pressure difference across said openings and the gas flow rate through said housing.
A thermocouple assembly for measuring the temperature of a gaseous stream including at least one protected thermocouple junction surrounded by a housing spaced from said thermocouple, the space between said protected thermocouple and said housing being accessible to the gaseous stream,
- (a) an inlet and at least one outlet opening in said housing to produce gas flow through the space between said thermocouple and ..the.!. said housing, the inlet opening and thermocouple junction being axially aligned, (b) means to maximize the gas flow rate ..throught.!. through said space comprising locating the outlet opening in said housing substantially at the gas separation point for the gaseous boundary layer on the exterior of the housing whereby the gas pressure at the outlet opening is minimized and the pressure differential between inlet and outlet openings is maximized.
A thermocouple assembly for measuring the temperature of a fluid stream comprising:
- (a) a casing;
- (b) a first pair of dissimilar wires disposed in said casing and forming a first thermocouple junction;
- (c) a second pair of dissimilar wires disposed in said casing and forming a second thermocouple junction axially spaced from said first thermocouple junction;
- (d) insulation dispersed in said casing and separating said dissimilar wires from said casing and from each other;
- (e) a protective housing spaced apart from and surrounding at least a portion of said casing containing a first thermocouple junction;
- (f) means to allow a part of the heated stream to flow through said protective housing and past said casing in the area of the thermocouple junctions, including:
- (1) an inlet opening in said housing positioned essentially along the flow axis of the stream, and
- (2) at least one outlet opening in said housing downstream from the inlet opening to establish a flow path through said housing;
- and
- (g) means for increasing the flow rate of the fluid through said housing by locating the outlet opening at a minimum fluid pressure point, thereby maximizing the pressure difference between inlet and outlet openings to provide rapid response of the thermocouple to changes in fluid stream
- temperature.
Dependencies are inferred from the claim text.