CN110823398B

CN110823398B - Device for improving universality of ferrule type thermocouple

Info

Publication number: CN110823398B
Application number: CN201910877630.XA
Authority: CN
Inventors: 俞凯耀
Original assignee: Zhejiang International Maritime College
Current assignee: Zhejiang International Maritime College
Priority date: 2019-09-17
Filing date: 2019-09-17
Publication date: 2021-07-06
Anticipated expiration: 2039-09-17
Also published as: CN110823398A

Abstract

The invention relates to the technical field of temperature detection equipment, in particular to a device for improving the universality of a ferrule type thermocouple, which comprises a substitute box cover, a compression nut and a substitute thermocouple, wherein the substitute box cover is a cylindrical shell with an opening at one end and a closed end, the open end of the substitute box cover is provided with an outward flange, one end of the compression nut is in threaded connection with a junction box, the other end of the compression nut is provided with a bulge clamped with the flange of the substitute box cover, the closed end of the substitute box cover is provided with a hole coaxial with the axis of a protection tube, the edge of the hole extends outwards along the axis direction of the protection tube to form a lead port, the substitute thermocouple is provided with two exposed measurement leads, the substitute thermocouple is inserted into the protection tube and. The substantial effects of the invention are as follows: the junction box cover is replaced by the replacement box cover, so that the thermocouple box is suitable for replacing thermocouples with various lengths; the influence of the external temperature on the temperature of the measurement lead replacing the thermocouple is reduced, and the temperature detection accuracy is improved.

Description

Device for improving universality of ferrule type thermocouple

Technical Field

The invention relates to the technical field of temperature detection equipment, in particular to a device for improving the universality of a ferrule type thermocouple.

Background

The thermocouple is a commonly used temperature measuring element in a temperature measuring instrument, directly measures temperature, converts a temperature signal into a thermal electromotive force signal, and converts the thermal electromotive force signal into the temperature of a measured medium through an electric instrument. The appearance of various thermocouples is very different according to needs, but the basic structures of the thermocouples are almost the same, and the thermocouples are generally composed of main parts such as a thermode, an insulating sleeve protection tube, a junction box and the like, and are generally matched with a display instrument, a recording instrument and an electronic regulator for use. The working principle is the thermoelectric effect. When two different conductors or semiconductors a and B form a loop, and the two ends of the loop are connected with each other, as long as the temperatures at the two junctions are different, one end is at T, called working end or hot end, and the other end is at T0, called free end, also called reference end or cold end, an electromotive force is generated in the loop, and the direction and magnitude of the electromotive force are related to the materials of the conductors and the temperatures of the two junctions. This phenomenon is called "thermoelectric effect", the circuit formed by the two conductors, called "thermocouple", the two conductors called "hot electrode", and the electromotive force generated, called "thermoelectric force".

Ferrule thermocouples, i.e., assembly thermocouples, are used as transmitters for measuring temperatures, usually in conjunction with display instruments, recording instruments, and electronic regulators. It can directly measure the surface temperature of liquid, vapor and gas media and solids in various production processes ranging from 0 ℃ to 1800 ℃. Therefore, the method is widely applied to industrial equipment with temperature detection or automatic temperature control, such as thermal power plant complete equipment. According to the operation rule of the thermal power plant unit, the temperature deviation of main equipment must not exceed the set temperature by +/-10 ℃, and the temperature measurement value has great influence on the operation condition. The temperature measuring element is already installed on a temperature measuring point along with the complete equipment in the process of establishing the complete equipment of the thermal power generating unit. With the operation of production, the defects of aging, damage or inaccurate temperature measurement can be generated. At this time, replacing the whole bite type thermocouple requires custom-processing of a protection tube, a mounting member, and the like which are mounted and matched with the temperature measuring point corresponding to the complete equipment. Time consuming, costly and wasteful, maintenance solutions are usually employed that replace only the built-in thermocouple wires. Due to the factors of various models, different manufacturers and the like, the matching performance of the purchased thermocouple wire and other parts of the conventional ferrule type thermocouple is poor, so that the temperature measuring part of the thermocouple cannot be tightly attached to the end of the sleeve, and a measuring error is generated. There is a need to develop a device that improves the versatility of a ferrule type thermocouple while still providing sufficient temperature measurement accuracy after maintenance.

Chinese patent CN108036871A, published 2018, 5, month and 15, discloses a pressure spring fixed thermocouple, which belongs to the field of temperature sensors and can improve the sensitivity and application range of thermocouples. One side of a pressure spring is provided with a heat-shrinkable sleeve and a compensation wire, and the other side of the pressure spring is provided with a locking snap spring, a stud, a heat-insulating silica gel plug, a stainless steel metal sleeve, a thermocouple wire working end and a red copper sheet; the pressure spring fixes the position of the locking clamp spring, the stud and the pressure spring form a compression structure, a U-shaped pin on the stud and a groove on the locking clamp spring are matched to form the locking structure, a fine through hole is formed in the middle of the heat insulation silica gel plug, one end of the heat insulation silica gel plug is plugged into the metal sleeve, one end of the metal sleeve, which is close to the pressure spring, is compressed on the shielding layer, the working end of the thermocouple wire in the metal sleeve penetrates through the through hole in the middle of the heat insulation silica gel plug to extend out, the working end of the thermocouple wire is connected with the red copper sheet, and a gap between the bottom of the heat insulation silica gel plug and the red copper. However, the technical scheme has the following defects that the parts of the conventional ferrule type thermocouple need to be changed, the silica gel has an applicable temperature range, and the silica gel is not suitable for being used in a thermal power unit because of the existence of a high-temperature working medium in the thermal power unit and cannot be suitable for finished thermocouple wires with various lengths and diameters.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the prior clamping sleeve type thermocouple has poor universality. The device is convenient to refit, wide in temperature application range and capable of improving the universality of the ferrule type thermocouple.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a device for improving the universality of a ferrule type thermocouple comprises a protection tube, an installation piece, a junction box, an insulating sheath, a mounting plate, a junction box cover and a thermocouple, wherein the junction box is fixedly arranged at one end of the protection tube, the installation piece is fixedly arranged in the middle of the protection tube and is in threaded connection with equipment to be tested, the other end of the protection tube is sealed and extends into the equipment to be tested, the mounting plate is detachably arranged in the junction box, one end of the thermocouple is fixedly clamped with the mounting plate, the other end of the thermocouple is close to or attached to the inner wall of the sealed end of the protection tube, two binding posts are arranged on the mounting plate, two outgoing lines of the thermocouple are respectively connected with one binding post, a wiring port is arranged on the junction box, the junction box cover is arranged on the, replace lid open end shape and terminal box matching, it has outside turn-ups to replace the lid open end, gland nut one end and terminal box threaded connection, the gland nut other end have with the arch of the turn-ups joint of replacing the lid, replace the lid blind end and open and have the hole coaxial with the protection tube axle center, the edge in hole outwards extends along protection tube axle center direction and forms and draws the mouth, replace the thermocouple and have two measurement wires that expose, replace the thermocouple and insert the protection tube and wear out and draw the mouth, two measurement wire is connected with a terminal respectively. Replace the lid and replace the junction box lid, replace the hole and the opening of drawing of lid processing, can adapt to the replacement thermocouple of multiple length, the length that replaces the thermocouple is greater than the length of protection tube, can guarantee to replace thermocouple sense terminal and protection tube bottom butt.

Preferably, the protective cover further comprises a protective cover, the protective cover is a spherical shell with an opening at one end, the opening of the protective cover is matched with the shape of the leading port, and the opening of the protective cover is fixedly connected with the leading port. The shield protects the measurement leads instead of the thermocouple.

Preferably, the damping device further comprises a shield adjusting nut, the opening of the shield is provided with an extending section, an external thread is processed on the outer side wall of the extending section, an internal thread matched with the extending internal nut is processed on the inner wall of the shield adjusting nut, the extending section of the shield is in threaded connection with the shield adjusting nut, the shield adjusting nut is in rotating connection with the leading port, and damping is arranged between the shield adjusting nut and the leading port. The shield adjustment nut can adjust the position of the shield to accommodate replacement thermocouples of different lengths.

Preferably, the shell of the shield sequentially comprises a flame retardant layer, a heat insulation layer, a support layer, a shielding layer and a protective layer from inside to outside, wherein the heat insulation layer is a spherical shell layer formed by foam with a set thickness, the support layer is made of rigid plastics, the shielding layer is a metal mesh layer, and the protective layer is made of a rubber layer covered on the shielding layer. The guard shield can be better with the measurement lead wire and the external world of replacing the thermocouple keep apart, avoid replacing the measurement lead wire temperature of thermocouple to receive external influence.

Preferably, the thermocouple protection device further comprises a sliding cap, an elastic block and a spring, one end of the sliding cap is connected with the inner wall of the lead opening in a clamping mode, the other end of the sliding cap extends inwards to form a boss, the elastic block is fixedly installed on the inner wall of the boss of the sliding cap and is abutted to the outer wall of the replacement thermocouple, the top of the lead opening extends inwards to form a supporting block, and the spring is installed between the sliding cap and the lead opening and enables the sliding cap to have the tendency of moving towards the protection tube. Under the action of the spring, the substitute thermocouple is tightly attached to the bottom of the protection tube, so that the temperature detection accuracy and response rate are improved, and the accuracy of detecting dynamic temperature is improved.

Preferably, the thermocouple heat conduction device further comprises a plurality of heat conduction blocks, the measurement lead wire replacing the thermocouple comprises a metal core and an insulating sheath covering the metal core, two through holes are formed in the heat conduction blocks, the two measurement lead wires respectively penetrate through the through holes, the inner wall of each through hole is abutted to the outer edge of the insulating sheath, and the plurality of heat conduction blocks are distributed along the part, exposed out of the lead port, of the two measurement lead wires. The heat conduction block can enable the temperatures of the two measuring wires to be closer, and the accuracy of a temperature detection result is improved.

Preferably, the heat conduction block is a metal block. The metal block has better thermal conductivity, for example, the thermal conductivity of pure aluminum is 237W/(m.K), the thermal conductivity of pure copper is 401W/(m.K), the temperatures of the two measuring wires can be closer, and the accuracy of the temperature detection result is improved.

Alternatively, the heat conduction block is a silicon block, the parts of the insulating skins of the two measuring wires, which are positioned in the area of the heat conduction block, are peeled off, and the heat conduction block is abutted with the metal core. The heat conduction coefficient of silicon is 150W/(m.K), has higher heat conductivity, and the silicon briquette is the insulator simultaneously, can with metal core direct contact, for metal heat conduction piece need set up outside insulating skin, the temperature of two measurement wires of balanced that the silicon briquette can be better.

The substantial effects of the invention are as follows: the junction box cover is replaced by the replacement box cover, so that the thermocouple box is suitable for replacing thermocouples with various lengths; the measuring lead of the substitute thermocouple is protected by the protective cover, the influence of the external temperature on the temperature of the measuring lead of the substitute thermocouple is reduced by the protective cover and the heat conducting block, and the temperature detection accuracy is improved.

Drawings

Fig. 1 is a schematic structural diagram of a ferrule thermocouple in the prior art.

Fig. 2 is a schematic view of an alternative lid structure according to an embodiment.

Fig. 3 is a schematic structural diagram of a shield and a heat conduction block according to an embodiment.

FIG. 4 is a schematic structural diagram of a sliding cap according to an embodiment.

FIG. 5 is a schematic view of a silicon block structure according to an embodiment.

Wherein: 1. the device comprises a wiring port, 2, a mounting plate, 3, a thermocouple, 4, a protection tube, 5, a mounting piece, 6, an insulating sheath, 7, a wiring box cover, 8, a wiring terminal, 9, a replacement thermocouple, 10, a compression nut, 11, a measurement lead, 12, a lead port, 13, a replacement box cover, 14, a protective cover, 15, a protective cover adjusting nut, 16, a heat conducting block, 17, a sliding cap, 18, a spring, 19, a metal core, 20 and an insulating sheath.

Detailed Description

The following provides a more detailed description of the present invention, with reference to the accompanying drawings.

The first embodiment is as follows:

the utility model provides an improve device of 3 commonality of cutting ferrule formula thermocouple, as shown in fig. 1, assembled thermocouple 3 includes protection tube 4 among the prior art, installed part 5, the terminal box, insulating sheath 6, mounting panel 2, terminal box lid 7 and thermocouple 3, terminal box fixed mounting is in 4 one ends of protection tube, installed part 5 fixed mounting at 4 middle parts of protection tube and with the equipment threaded connection that awaits measuring, 4 other ends of protection tube seal and stretch into the equipment that awaits measuring, 2 demountable installation in the terminal box of mounting panel, 3 one end of thermocouple and 2 fixed joint of mounting panel, the 3 other end of thermocouple is close to or the inner wall of attached 4 blind ends of protection tube, be equipped with two terminal 8 on the mounting panel 2, two outgoing lines of thermocouple 3 are connected with a terminal 8 respectively, be equipped with wiring mouth 1 on the terminal. As shown in fig. 2, the embodiment includes a substitute box cover 13, a compression nut 10 and a substitute thermocouple 9, the substitute box cover 13 is a cylindrical shell with one open end and the other closed end, the open end of the substitute box cover 13 is matched with the terminal box in shape, the open end of the substitute box cover 13 is provided with an outward flange, one end of the compression nut 10 is in threaded connection with the terminal box, the other end of the compression nut 10 is provided with a bulge clamped with the flange of the substitute box cover 13, the closed end of the substitute box cover 13 is provided with a hole coaxial with the axis of the protection tube 4, the edge of the hole extends outwards along the axis direction of the protection tube 4 to form a leading port 12, the substitute thermocouple 9 is provided with two exposed measurement leads 11, the substitute thermocouple 9 is inserted into the protection tube 4. Replace lid 13 and replace the junction box lid 7, replace the hole and the opening 12 that draw that lid 13 was processed, can adapt to the replacement thermocouple 9 of multiple length, the length of replacing thermocouple 9 is greater than the length of protection tube 4, can guarantee to replace thermocouple 9 sense terminal and protection tube 4 bottom butt.

As shown in fig. 3, the protective cover 14 is a spherical shell with an opening at one end, the opening of the protective cover 14 matches with the shape of the leading port 12, and the opening of the protective cover 14 is fixedly connected with the leading port 12. The shield 14 protects the measuring leads 11 instead of the thermocouples 9. The opening of guard shield 14 has the extension section, and extension section lateral wall processing has the external screw thread, and 15 inner walls of guard shield adjusting nut processing have with extend the internal thread that interior nut matches, the extension section and the 15 threaded connection of guard shield adjusting nut of guard shield 14, and guard shield adjusting nut 15 rotates with leading mouthful 12 and is connected, has the damping between guard shield adjusting nut 15 and the leading mouthful 12. The shield adjustment nut 15 enables adjustment of the position of the shield 14 to accommodate replacement thermocouples 9 of different lengths. The casing of the protective cover 14 is sequentially provided with a flame retardant layer, a heat insulation layer, a support layer, a shielding layer and a protective layer from inside to outside, wherein the heat insulation layer is a spherical shell layer formed by foam with a set thickness, the support layer is formed by rigid plastic, the shielding layer is a metal mesh layer, and the protective layer is formed by a rubber layer covered on the shielding layer. The protective cover 14 can better isolate the measuring lead of the replacement thermocouple 9 from the outside, and the temperature of the measuring lead of the replacement thermocouple 9 is prevented from being influenced by the outside. The measurement lead 11 replacing the thermocouple 9 comprises a metal core 19 and an insulating sheath 20 covering the metal core 19, two through holes are processed on the heat conduction block 16, the two measurement leads 11 respectively penetrate through the through holes, the inner walls of the through holes are abutted to the outer edge of the insulating sheath 20, and a plurality of heat conduction blocks are distributed along the parts of the two measurement leads 11, which are exposed out of the lead opening 12. The heat conducting block 16 can enable the temperatures of the two measuring wires 11 to be closer, and the accuracy of the temperature detection result is improved. The heat conduction block 16 is a metal block. The metal block has good thermal conductivity, for example, the thermal conductivity of pure aluminum is 237W/(m.K), and the thermal conductivity of pure copper is 401W/(m.K), so that the temperatures of the two measuring wires 11 can be closer, and the accuracy of the temperature detection result can be improved.

As shown in fig. 4, one end of the sliding cap 17 is clamped with the inner wall of the leading port 12, the other end of the sliding cap 17 extends inwards to form a boss, the elastic block is fixedly arranged on the inner wall of the boss of the sliding cap 17 and is abutted against the outer wall of the substitute thermocouple 9, the top of the leading port 12 extends inwards to form an abutting block, and the spring 18 is arranged between the sliding cap 17 and the leading port 12 and enables the sliding cap 17 to have a tendency of moving towards the protection tube 4. Under the action of the spring 18, the substitute thermocouple 9 is tightly attached to the bottom of the protection tube 4, so that the temperature detection accuracy and response rate are improved, and the accuracy of detecting dynamic temperature is improved.

As shown in fig. 5, the heat conducting block 16 is a silicon block, and the insulating sheath 20 of the two measuring wires 11 is partially peeled off in the area of the heat conducting block 16, so that the silicon block is formed by splicing and bonding for the convenience of installation. The heat-conducting block 16 abuts against the metal core 19. The heat conduction coefficient of silicon is 150W/(m.K), and the silicon block has high heat conduction capability, is an insulator, can be in direct contact with the metal core 19, and can better balance the temperature of the two measurement leads 11 compared with the condition that the metal heat conduction block 16 needs to be arranged outside the insulating sheath 20.

The above-described embodiments are only preferred embodiments of the present invention, and are not intended to limit the present invention in any way, and other variations and modifications may be made without departing from the spirit of the invention as set forth in the claims.

Claims

1. A device for improving the universality of a ferrule type thermocouple comprises a protection tube, an installation piece, a junction box, an insulating sheath, a mounting plate, a junction box cover and a thermocouple, wherein the junction box is fixedly arranged at one end of the protection tube, the installation piece is fixedly arranged in the middle of the protection tube and is in threaded connection with equipment to be tested, the other end of the protection tube is sealed and extends into the equipment to be tested, the mounting plate is detachably arranged in the junction box, one end of the thermocouple is fixedly clamped with the mounting plate, the other end of the thermocouple is close to or attached to the inner wall of the sealed end of the protection tube, two binding posts are arranged on the mounting plate, two outgoing wires of the thermocouple are respectively connected with the two binding,

the junction box cover comprises a replacing box cover and a compression nut, the thermocouple is a replacing thermocouple, the replacing box cover is a cylindrical shell with an opening at one end and a closed end at the other end, the shape of the opening end of the replacing box cover is matched with that of the junction box, an outward flange is arranged at the opening end of the replacing box cover, one end of the compression nut is in threaded connection with the junction box, a bulge clamped with the flange of the replacing box cover is arranged at the other end of the compression nut, a hole coaxial with the axis of the protection tube is formed in the closed end of the replacing box cover, the edge of the hole extends outwards along the axis direction of the protection tube to form a leading opening, the replacing thermocouple is provided with two exposed measuring leads, the replacing thermocouple is inserted into the protection;

the protective cover is a spherical shell with an opening at one end, the shape of the opening of the protective cover is matched with that of the leading port, and the opening of the protective cover is fixedly connected with the leading port;

the thermocouple temperature measuring device is characterized by further comprising a plurality of heat conducting blocks, wherein the measuring lead of the replacement thermocouple comprises a metal core and an insulating sheath covering the metal core, two through holes are formed in the heat conducting blocks, the two measuring leads respectively penetrate through the through holes, the inner wall of each through hole is abutted against the outer edge of the insulating sheath, and the plurality of heat conducting blocks are distributed along the part, exposed out of the lead port, of the two measuring leads;

the heat conduction block is a silicon block, the parts of the insulating skins of the two measuring wires, which are positioned in the area of the heat conduction block, are peeled off, and the heat conduction block is abutted to the metal core.

2. The device for improving the universality of the ferrule type thermocouple according to claim 1,

still include guard shield adjusting nut, the opening of guard shield has the extension section, extension section lateral wall processing has the external screw thread, guard shield adjusting nut inner wall processing have with extend the internal thread that interior nut matches, the extension section and the guard shield adjusting nut threaded connection of guard shield, guard shield adjusting nut with draw mouthful to rotate and be connected, guard shield adjusting nut with draw and have the damping between mouthful.

3. The device for improving the universality of the ferrule type thermocouple according to the claim 1 or 2,

the shell of the shield sequentially comprises a flame-retardant layer, a heat-insulating layer, a supporting layer, a shielding layer and a protective layer from inside to outside, wherein the heat-insulating layer is a spherical shell layer formed by foam with a set thickness, the supporting layer is made of rigid plastic, the shielding layer is a metal mesh layer, and the protective layer is made of a rubber layer covering the shielding layer.

4. The device for improving the universality of the ferrule type thermocouple according to the claim 1 or 2,

still include sliding cap, elastic block and spring, sliding cap one end and lead the interior wall joint of mouth, the inside extension of sliding cap other end has the boss, and elastic block fixed mounting is on sliding cap's boss inner wall, and elastic block and replacement thermocouple outer wall butt lead the inside extension in mouth top and have to support the piece, spring mounting is sliding cap and is leading between the mouth and make sliding cap have the trend to the protection tube removal.

5. The device for improving the universality of the ferrule type thermocouple according to claim 1,

the heat conduction block is a metal block.