Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
  • G01N27/403—Cells and electrode assemblies
  • G01N27/406—Cells and probes with solid electrolytes
  • G01N27/4062—Electrical connectors associated therewith
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
  • G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
  • G01N27/403—Cells and electrode assemblies
  • G01N27/406—Cells and probes with solid electrolytes
  • G01N27/407—Cells and probes with solid electrolytes for investigating or analysing gases

Definitions

• the invention is based on a sensor, in particular for determining the oxygen content in exhaust gases from
• a generic sensor is known for example from DE-OS 28 05 598, in which lead out of a metallic housing electrical connection cable from one
• Jacket tube are encased.
• the jacket tube is used to conduct a reference air shielded from splash water and air contaminants into the housing of the sensor as a reference atmosphere.
• the sensor according to the invention with the characterizing features of the main claim has the advantage that a better supply of the reference atmosphere takes place in the housing. Due to the relatively large surface area of the cable sheath, sufficiently dimensioned gas-permeable sections are possible through which sufficient reference air can penetrate the interior of the cable sheath and from there into the housing. At the same time, moisture or impurities are prevented from getting into the housing. Due to the large surface area of the gas-permeable sections of the cable sheathing, a very low specific permeability of the porous material can be set, which makes the otherwise critical penetration of liquid hydrocarbons difficult. A tight connection between the insulation of the connection cable and the cable entry is no longer necessary.
• a technically favorable connection of the cable sheath to the housing of the sensor is achieved in that the cable sheath is shrunk onto the opening of the housing.
• the simultaneous caulking of a cable bushing held in the opening with a clamping ring placed over the cable sheathing further simplifies the assembly of the sensor.
• the cable gland can also be used advantageously as strain relief for the connection cable.
• FIG. 1 shows a sensor with a connecting line according to the invention and FIG. 2 shows an enlarged section X according to FIG. 1.
• Figure 1 shows a sensor 10, for example a ⁇ probe, with a housing 13 in which a sensor element 14 is fixed gas-tight.
• the sensor 10 is connected to a connecting line 11, which consists of a gas-permeable cable sheath 12, in which connecting cables 18 for the sensor element 14 are guided.
• the housing 13 has a section 15 on the measurement gas side and a section 16 on the connection side.
• the connection cables 18 each have an electrical conductor 19 which is surrounded by an insulation jacket 20.
• a protective tube 22 with gas inlet and outlet openings 23 is fastened to the measuring gas side section 15 of the housing 13.
• the protective tube 22 surrounds the sensor element 14 protruding from the housing 13 on the measuring gas side
• Section 15 is also provided with a thread 24, with which the sensor 10 is fastened in an exhaust pipe, not shown.
• a metallic protective sleeve 30 is attached to the connection-side section 16 of the housing 13 in a gas-tight manner by means of a radially circumferential weld seam 31.
• the protective sleeve 30 surrounds the sensor element 14, which also protrudes from the housing 13 on the connection side, and forms an interior 33 into which a reference atmosphere, for example air, for a reference electrode (not shown) of the sensor element 14 is introduced.
• connection contacts not shown, which are contacted with contact parts 35.
• the contact parts 35 are arranged in, for example, a two-part connector 40, the two parts of the connector 40 being held together by an annular spring element 41. As a result, the contact parts 35 are pressed onto the connection contacts (not shown) of the sensor element 14.
• the cable-side section of the contact parts 35 is designed with a crimp connection 43.
• the contact parts 35 are connected to the connecting cables 18 by means of the crimp connections 43 (FIG. 2).
• the protective sleeve 30 is designed according to Figure 2 at its connection end with a cylindrical portion 45 with an opening 46, the cylindrical
• Section 45 has a small diameter compared to the other part of the protective sleeve 30.
• the opening 46 is closed with a cable bushing 50.
• the cable bushing 50 is made of PTFE, for example, and has 18 corresponding to the number of connecting cables to be passed through
• the through holes 51 are dimensioned so that a gap 52 is formed between the insulation jacket 20 of the connecting cable 18 and the protective sleeve 30, through which the reference air can get into the interior of the protective sleeve 30.
• the through holes 51 are designed such that the crimp connections 43 get caught in the cable bushing 50.
• the cable sheath 12 is, for example, a PTFE hose with a plug end 56 and a probe end 57.
• the PTFE hose has pores on its outer surface through which the reference air can penetrate into the interior of the hose. The pore size is so small that there is a specific permeability that prevents the otherwise critical penetration of liquid hydrocarbons.
• the connecting cables 18 are led out and contacted with a connector, not shown, which is connected to a control unit, also not shown.
• the PTFE tube is surrounded by a sleeve 58 which squeezes the PTFE tube together.
• a sealing element can expediently be arranged within the PTFE tube in the area of the sleeve 58, so that when the tube is squeezed together it is at least sealed watertight.
• the sensor-side end 57 of the hose is placed over the cylindrical section 45. This is done, for example, by heating and then shrinking the hose onto the cylindrical section 45 of the protective sleeve 30. In addition, a clamping ring 59 is pushed over the sensor-side end 57 of the hose, which is then caulked radially by means of a caulking tool. As a result, the cylindrical section 45 of the protective sleeve 30 is caulked to the cable bushing 50, as a result of which the cable bushing 50 is firmly anchored in the opening 46.
• the porous PTFE tube is produced by stretching the PTFE material according to a method known per se. But it is also conceivable, the PTFE hose to stretch only on one or more sections, so that there is only a section-wise porosity along the tube.
• Another possibility for executing a gas-permeable cable sheath 12 is that a material which is inherently dense is made air-permeable by laser beam bombardment or by the finest mechanically introduced needle pricks.

Landscapes

• Chemical & Material Sciences (AREA)
• Life Sciences & Earth Sciences (AREA)
• Health & Medical Sciences (AREA)
• Physics & Mathematics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Molecular Biology (AREA)
• Analytical Chemistry (AREA)
• Biochemistry (AREA)
• General Health & Medical Sciences (AREA)
• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Measuring Oxygen Concentration In Cells (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1996
  • 1996-03-23 DE DE19611572A patent/DE19611572A1/de not_active Withdrawn
  • 1996-11-20 JP JP9533911A patent/JPH11506216A/ja not_active Ceased
  • 1996-11-20 KR KR1019970708065A patent/KR19990014723A/ko not_active Application Discontinuation
  • 1996-11-20 WO PCT/DE1996/002206 patent/WO1997036172A1/de not_active Application Discontinuation
  • 1996-11-20 CN CN96193551A patent/CN1183141A/zh active Pending
  • 1996-11-20 EP EP96945737A patent/EP0827590A1/de not_active Withdrawn

Non-Patent Citations (1)

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