CS196727B1 - Dismantable probe for determination of the oxygen contents in the furnace atmosphere,smoke gases and other heat-technical appliances - Google Patents

Description

The present invention relates to a removable probe for determining the oxygen content of furnace atmosphere, flue gases and other thermo-technical devices with a solid ceramic electrolyte sensor based on a concentration galvanic cell.

Until now, the problem of measuring the oxygen content in hot atmospheres has been solved by analyzers which were equipped for sampling the atmosphere and the determination was carried out outside the measured environment by magnetic analyzers, Orsat instrument, etc.) or by probes with solid electrolyte sensors which are bearing structure or parts thereof, as described in MS. The invention discloses a sensor which is soldered by glass solder and which has a limited temperature range of up to 1000 ° C. Also, the design of the stainless steel probe on the cell does not allow longer exposure at temperatures above 1000 ° C. Other probes have the sensors firmly connected to the ceramic support tube and their drawback is that if the sensor electrodes are damaged, for example by a strongly reducing atmosphere, the entire probe needs to be replaced.

These disadvantages are overcome by the invention which is based on the fact that the mounted sensor sealed in the support tube with a labyrinth and a flexible, refractory, chemically resistant seal and provided with an external and internal electrode abuts both on the thermocouple and on the support tube. a mechanical joint that is rigidly connected to the support tube in which the conductor is located. The upper part of the mechanical joint is arranged to protect the sensor from flame and fouling, for example with a collar.

An advantage of the invention is that the probe sensor is attached to the ceramic support tube by a removable mechanical joint with a ceramic material that does not react with either the sensor material or the support tube material. The removable joint may be a threaded or Bayonet-type joint or the like. The shape of the joint shall be such as to form a labyrinth which, even without sealing, would make it difficult for the gas to communicate from the inside or from the outside. The sealing may be performed with ceramic fibers resistant to operating temperatures. The contact between the sensor electrodes and the thermocouple or the connecting wires is formed by the mechanical pressure exerted by the closure (protrusion). The material of the electrodes, thermocouples, and the connecting conductor is of a material resistant to temperatures and environments, for example to the oxidizing environment and to a temperature of 1300 ° C platinum, platinum-rhodium alloy, for tungsten-molybdenum reducing environment. The solid electrolyte sensor material is also selected according to the temperature at which the probe is to be operated. Up to a temperature of 700 ° C, a solid bismuth oxide-based electrolyte BI2O3 is used up to a temperature of 1400 ° C, a solid zirconium or thorium oxide electrolyte ZrO2, ThCh or mullite. Protection against chemical corrosion of the electrodes is achieved by a porous coating based on alumina Al2O3. The advantages of the present invention will be utilized in the measurement of the oxygen content in furnaces, combustion chambers and other thermo-technical equipment for continuous and long-term monitoring of the oxygen content.

The invention will be explained and described in more detail by means of a drawing showing a cross-section of a probe using an example of a possible probe arrangement.

The probe consists of a solid electrolyte sensor 1 in the form of a one-sided closed electrode coated cylinder. The outer electrode 2 extends below the shoulder of the sensor to form a contact in the conductor 5. The inner electrode 3 contacts the thermocouple 6. The sensor 1 is pressed by the upper part of the mechanical joint 4 which is formed in the projection 12 by the thread 8 to the lower part of the mechanical joint 9. is sealed to the support structure 7 in whose capillaries 10 the conductor 5 passes. The seal 11 outside the labyrinth formed by the upper part of the mechanical connection 4 by the sensor! 1 and the support tube 7 is also provided by a ceramic fiber seal 11 which is refractory and chemically resistant. The sensor 1 is replaced by unscrewing the upper part of the mechanical connection 4 by removing the sensor 1 and reinserting the new sensor 1, possibly adding a ceramic fiber seal 11. The upper part of the mechanical joint 4 is formed in a collar 13, which protects the actual sensor 1 from flame blasting and fouling of solid and liquid particles from the measured environment.

Claims (2)

A removable probe for the determination of oxygen content in furnace, flue gas and other thermal equipment with a solid ceramic electrolyte sensor, characterized in that the mounted sensor (1) is sealed in the support tube (7) by a labyrinth and resilient, refractory, chemically a resistive seal (11) and provided with an external electrode (2) and an internal electrode (3) abuts both the thermocouple (6) and the face of the support tube (7), where it is held by a projection (12) of the upper part of the mechanical connection (4) releasably connected to the lower part of the mechanical joint (9) which is rigidly connected to the support tube (7) in which the conductor (5) is located. Detachable probe according to claim 1, characterized in that the upper part of the mechanical joint (4) is arranged as protection against the flame and fouling of the sensor (1), for example provided with collars (13).