Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N1/00—Sampling; Preparing specimens for investigation
  • G01N1/02—Devices for withdrawing samples
  • G01N1/22—Devices for withdrawing samples in the gaseous state
  • G01N1/2247—Sampling from a flowing stream of gas
  • G01N1/2258—Sampling from a flowing stream of gas in a stack or chimney

Definitions

• the invention relates to an insert tube for a gas analysis system to be used in the measuring and analysis of hot gasses as for instance arise from various processes in the steel industry.
• the gas analysis systems used for these measurements are provided with an insert tube that protrude into the flue-gas stack at a distance from the converter, blast furnace or like equipment.
• tubes of corrosion-resistant metal alloys that in the steel industry are known under the term "superalloys" or "high-performance alloys".
• the predominant alloying element in these alloys is typically nickel.
• Other alloying elements are added to nickel including varying percentages of the elements molybdenum, chromium, cobalt, iron, copper, manganese, titanium, zirconium, aluminium, carbon and tungsten.
• the main characteristics of these "super alloys” are resistance against a high-temperature environment and severely corrosive and/or erosion-prone environments. Insert tubes made from one of these "super alloys” are able to survive such conditions much longer than insert tubes of more common steel alloys.
• one or more of the objectives of the invention are realized by providing insert tube for a gas analysis system, wherein the insert tube is suitable to take gas samples out of a high temperature, corrosive and/or erosive environment and wherein the insert tube comprises a ceramic material.
• the insert tube comprising a ceramic material it has proven in tests that the insert tube has a far better stand time than the previous used insert tubes made of the "super alloys". Further advantages of such an insert tube are that the insert tube will not bend because of high temperatures, corrosion/erosion and also will not get clogged easily with particles present in the flue-gasses.
• at least part of the tube is made from a ceramic material. Since not the complete length of the insert tube is brought into the stack it is an option to only make that part of the insert tube of ceramic material that will be directly exposed to the high temperature and aggressive environment inside the stack.
• the whole insert tube is made from a ceramic material which has the advantage that there is no need to provide a transition from a ceramic pipe to a steel pipe or a connection between such pipes.
• the insert tube comprises a steel tube with a ceramic coating.
• the coating could be applied on the outside or the inside of the steel tube or on the outside as well as the inside of the steel tube.
• An insert tube with a coating only on the outside has as a disadvantage that the inside of the insert tube will still get corroded easily and at the same time the insert tube will still get easily clogged with dust particles present in the flue-gasses.
• the ceramic material for a ceramic insert tube is a non-oxide ceramic material.
• the non-oxide ceramic materials include silicon carbide, silicon nitride, aluminium nitride, boron carbide, boron nitride and "SIALON" which is silicon nitride with a small percentage of aluminium oxide added.
• the ceramic material comprises a carbide and even more preferable a silicon carbide.
• a non-oxide ceramic material for the insert tube has proven in test to be able to withstand the high temperatures and corrosive environment very well.
• the ceramic material for an insert tube provided with a ceramic coating comprises a non-oxide ceramic material.
• the non-oxide ceramic materials comprise aluminium oxide, zirconium oxide, all combinations of these oxides, titanium oxide and aluminium titanate.
• Ceramic fibre ceramic materials can be used as well as metal matrix composites which are metals plus a reinforcement.
• a reinforcement could comprise particles, for instance A1203, SiC, long fibres, for instance A1203, Si02, short fibres for instance A1203, Si02, C, whiskers, for instance A1203, SiC and mixtures of particles and fibres.
• the ceramic coating depending on the coating material, is applied by chemical vapour deposition, physical vapour deposition, by thermal spraying or plasma spraying.
• the invention also provides in a connecting device to connect the insert tube to a gas analysis system, the connecting device comprising a fixing plate with an opening and clamping means to clamp an insert tube to the fixing plate in line with the opening in the fixing plate.
• the connecting device comprising a fixing plate with an opening and clamping means to clamp an insert tube to the fixing plate in line with the opening in the fixing plate.
• a raised edge is provided around the opening in the fixing plate and the clamping means comprise clamping members that each have a first portion, that is to engage the raised edge, and a second portion, that together are to clamp the insert tube. With the raised edge it is prevented that the clamping member can be secured too tight with the risk that the insert tube could be damaged.
• the raised edge has an undercut and that the first portion of the clamping members engage the undercut in the raised edge.
• a heat resistant and deformable lining material is provided at the sides of the clamping members facing each other when in use. With such a lining the clamping force will be distributed evenly over the surface area of the part of the insert tube in engagement with the clamping members.
• the clamping members are provided with one or more ripples at the sides facing each other when in use. With these ripples the deformable heat resistant lining material is kept in place and can not be squeezed out.
• a mounting plate is provided that is secured with spacers to the side of the fixing plate at which the clamping members are provided when in use and which is provided with a through hole to receive the insert tube.
• This mounting plate serves to mount the insert tube to an inlet for the insert tube at an appropriate location of the stack through which inlet the insert tube protrudes into the stack and into the flue-gasses.
• the mounting plate is provided with a raised edge around the through hole at the side of the mounting plate facing the fixing plate. This further raised edge prevents that the second portions of the clamping members can be clamped too tight to the insert tube. Moreover, with this further raised edge the heat resistant and deformable lining material is completely locked up.
• Fig.1 shows the insert tube inserted through a stack wall and part of the gas analysis system
• Fig.2 shows the inlet tube of the gas analysis system in an insulated casing
• Fig.3 shows the insert tube together with the connecting device.
• the insert tube 1 is shown inserted through an inlet pipe 2 through stack wall 3 into the stack 4.
• the stack wall 3 is provided with a heat resistant lining 5.
• a connecting flange 6 is provided to which insulated casing 7 is secured.
• the connecting flange 6 is fixed to inlet pipe 2 by means of a clamp 1 1.
• the insulated casing 7 is divided in a lower part 8 which is secured to connecting flange 6 and an upper part 9 that is removably connected to the lower part and fixed thereto with snap-connections 10.
• the lower part 8 of the insulated casing 7 is shown attached to connecting flange 6.
• an inlet tube 12 of the gas analysis system is provided that is connected by means of mounting plate 13 to fixing plate 15 of the connecting device 14 with which insert tube 1 is connected to the inlet tube 12.
• the connecting device 14 is further provided with a mounting plate 22 (see fig.3) spaced from fixing plate 15 and secured thereto. With this mounting plate 22 the connecting device 14 is fixed to connecting flange 6 and therewith the assembly of insert tube 1, connecting device 14 and inlet tube 12 are secured to inlet pipe 2 and consequently to stack wall 3.
• Inlet tube 12 is provided with heating elements 16, 17 to heat the inlet tube 12 to prevent that water or water containing components condensate against the wall of the inlet tube 12 or the further lining of the gas analysis system.
• the inlet tube 12 is provided with an outlet 19 for the flue-gas taken from the stack and an inlet 18 through which a pressurized gas, such as Nitrogen, can be fed through inlet tube 12 and insert tube 1 to remove clogged dust particles in the insert tube.
• a pressurized gas such as Nitrogen
• a feed through box 20 is mounted to connect the outlet 19 to a line to the gas analysis devices further downstream and a junction box 21 for the electrical power supply.
• Connecting device 14 comprises a fixing plate 15, a mounting plate 22, secured to the fixing plate 15 by means of spacers 23, and clamping means 24.
• the clamping means 24 consists of two clamping members 25 which are secured to each other by means of bolts 29.
• Both the fixing plate 15 and the mounting plate 22 are provided with a raised edge 26, 27 around openings in the respective plates in line with insert tube 1.
• the raised edge 26 is provided with an undercut and the clamping members with a first portion that is adapted to engage the undercut, as a result of which the clamping means 14 are secured to fixing plate 15 when the clamping members are secured against each other.
• the clamping members 25 are dimensioned to grip around raised edges 26, 27, therewith leaving a small space 28 between the clamping members 25 and the insert tube 1. Between the clamping members and the insert tube 1 a heat resistant and deformable material is applied which provides that the clamping force exerted on the insert tube 1 is evenly distributed. This allows to clamp the insert tube with sufficient force without the risk of locally exceeding the breaking strength of the insert tube 1.

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• Health & Medical Sciences (AREA)
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• General Physics & Mathematics (AREA)
• Immunology (AREA)
• Pathology (AREA)
• Sampling And Sample Adjustment (AREA)

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Citations (6)

• 2013
  • 2013-06-12 WO PCT/EP2013/001718 patent/WO2014040665A1/fr not_active Ceased

Patent Citations (6)

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