초록 ▼

A fluid sensor probe such as a temperature probe uses heat shrink tubing to seal and provide strain relief at a proximal end of the probe. The heat shrink tubing uses a layer of hot melt adhesive along its inside surface to form a strong bond and hermetic seal. The heat shrink tubing is applied as a

A fluid sensor probe such as a temperature probe uses heat shrink tubing to seal and provide strain relief at a proximal end of the probe. The heat shrink tubing uses a layer of hot melt adhesive along its inside surface to form a strong bond and hermetic seal. The heat shrink tubing is applied as an inner tubing around circuit wires extending into the probe and as an outer tubing around the inner tubing and around the proximal end of the probe housing. Together the inner tubing and the outer tubing can hermetically seal a substantial gap between the probe housing and the circuit wires. In a fast response probe, prior to closing the distal end of the probe housing with an end wall, openings are punched in a side wall of the probe housing against a mandrel. The openings permit fluid flow to contact the sensing element within the probe housing. Heat shrink tubing can be used to seal the circuit wires and prevent leakage.

대표청구항 ▼

The invention claimed is: 1. A method of making a fluid sensor probe, comprising: inserting a sensing element into a rigid sheath, the sensing element having an electrical response which changes as a function of a parameter of the fluid to be sensed, the rigid sheath extending longitudinally betwee

The invention claimed is: 1. A method of making a fluid sensor probe, comprising: inserting a sensing element into a rigid sheath, the sensing element having an electrical response which changes as a function of a parameter of the fluid to be sensed, the rigid sheath extending longitudinally between a proximal end and a distal end, such that the sensing element is disposed in the distal end of the rigid sheath, with circuit wires running longitudinally within the rigid sheath to the sensing element and extending out of the proximal end of the rigid sheath; and heat shrinking tubing around an exterior of the proximal end of the rigid sheath and around the circuit wires extending out of the proximal end of the rigid sheath. 2. The method of claim 1, further comprising: melting hot melt adhesive within the heat shrink tubing to hermetically seal the heat shrink tubing to the sheath and to the circuit wires. 3. The method of claim 2, wherein the heat shrinking and melting steps are performed by heating to at least 100째 C. 4. A method of making a fluid sensor probe, comprising: inserting a sensing element into a rigid sheath, the sensing element having an electrical response which changes as a function of a parameter of the fluid to be sensed, the rigid sheath extending longitudinally between a proximal end and a distal end, such that the sensing element is disposed in the distal end of the rigid sheath, with circuit wires running longitudinally within the rigid sheath to the sensing element and extending out of the proximal end of the rigid sheath: heat shrinking tubing about the proximal end of the rigid sheath and about the circuit wires extending out of the proximal end of the rigid sheath; and punching at least one opening in the distal end of the rigid sheath. 5. The method of claim 4, wherein the punching act comprises: placing a circumferential side wall of the sheath about a mandrel inserted through the distal end of the sheath while the distal end is still open; punching at least one opening in the circumferential side wall against the mandrel; removing the mandrel through the open distal end; and closing the distal end of the sheath. 6. The method of claim 1, wherein the heat shrinking act comprises: heat shrinking a first heat shrink tubing about at least one of the circuit wires; and heat shrinking a second heat shrink tubing about the first heat shrink tubing. 7. The method of claim 6 wherein the first heat shrink tubing is of a smaller pre-shrunk diameter than the second heat shrink tubing. 8. A method of making a fluid sensor probe, comprising: inserting a sensing element into a rigid sheath, the sensing element having an electrical response which changes as a function of a parameter of the fluid to be sensed, the rigid sheath extending longitudinally between a proximal end and a distal end, such that the sensing element is disposed in the distal end of the rigid sheath, with circuit wires running longitudinally within the rigid sheath to the sensing element and extending out of the proximal end of the rigid sheath; heat shrinking tubing about the proximal end of the rigid sheath and about the circuit wires extending out of the proximal end of the rigid sheath; electrically connecting a first lead of the sensing element to an exposed metallic core extending out of a dielectric sheath of a first circuit wire; heat shrinking tubing about a distal end of the dielectric sheath of the first circuit wire and about the exposed metallic core to seal the first circuit wire against internal leakage. 9. The method of claim 8, further comprising: opening at least one opening in the distal end of the rigid sheath to permit fluid flow within the rigid sheath proximate the sensing element. 10. The method of claim 1, wherein the sensed parameter is fluid temperature. 11. A method of forming a hermetic seal with a rigid sheath of a fluid sensing probe, comprising: heat shrinking a first tubing; and heat shrinking a second tubing into hermetic contact with the first tubing; such that the first and second tubings jointly form at least a portion of a hermetic seal blocking fluid from flowing longitudinally within the rigid sheath, despite the rigid sheath having openings which permit fluid to flow into the rigid sheath and into contact with a sensing element disposed within the rigid sheath. 12. The method of claim 11, wherein the second tubing is shrunk about a proximal end of the rigid sheath. 13. The method of claim 11, wherein the first tubing is of a smaller pre-shrunk diameter than the second tubing. 14. The method of claim 11, wherein the first tubing is shrunk about at least one circuit wire leading to the sensing element. 15. The method of claim 14, wherein the first tubing is shrunk into contact with a metallic core of the circuit wire. 16. A method of forming a fast response fluid sensing probe, comprising: opening at least one opening into a distal end of a probe to permit fluid to flow into contact with a sensing element disposed therein; electrically connecting the sensing element with a lead wire having a dielectric sheath disposed about a conductor; and forming a hermetic seal between the conductor and the dielectric sheath of the lead wire. 17. A method of forming a tubular sheath for a fast response fluid sensor probe, comprising: forming a tubular sheath, the tubular sheath having a circumferential side wall running longitudinally between an open distal end and an open proximal end; placing the circumferential side wall of the tubular sheath about a mandrel inserted through the open distal end; punching at least one opening in the circumferential side wall against the mandrel; removing the mandrel through the open distal end; and closing the distal end of the tubular sheath. 18. The method of claim 17, wherein the tubular sheath is formed of metal. 19. The method of claim 18, wherein the distal end of the tubular sheath is closed to have a generally flat end wall extending transverse to a longitudinal axis of the tubular sheath. 20. The method of claim 17, further comprising: placing a sensing element within the tubular sheath adjacent to the punched opening, with lead wires for the sensing element running the length of the tubular sheath and exiting the open proximal end of the tubular sheath; and sealing the open proximal end of the tubular sheath about the lead wires.