JP3108015U - Sheath thermocouple tip pad - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure a surface temperature of a device such as a pipe or a container by attaching a pad to the tip of a sheathed thermocouple and measuring a device whose temperature difference from the ambient temperature is large and a heat insulating material cannot be installed The purpose of the conventional pad is to solve the problem that an error occurs in the measured value due to the influence of the ambient temperature.
SOLUTION: A pad to be attached to the tip of a sheathed thermocouple is inserted into the pad, and a sheathed thermocouple with the thermocouple wire exposed from the tip is inserted into the pad. The structure is
[Selection] Figure 1

Description

  The present invention relates to a sheathed thermocouple tip pad, and relates to a metal pad that is attached to the tip of a sheathed thermocouple and brought into contact with an object to be measured in order to measure the surface temperature of the device with the sheathed thermocouple. .

  Sheath thermocouples are used to protect thermocouple wires from external environments such as mechanical shocks and corrosive atmospheres, and to ensure insulation between thermocouple wires and between thermocouple wires and surrounding metals. In addition, the thermocouple element is housed in a metal sheath, and there are two types, a non-grounding type and a grounding type.

These structures are shown in FIG. 3, FIG. 4, and FIG. 3 is a non-grounded sheath thermocouple, FIG. 4 is a grounded sheath thermocouple, and FIG. 5 is a cross-sectional view of FIGS. In both cases, an inorganic insulating material 102 such as magnesium oxide (MgO) or aluminum oxide (Al ₂ O ₃ ) is interposed in a metal sheath 101, and a plus side thermocouple wire 103 and a minus side thermocouple wire. 104, a temperature sensing portion 113 is formed on the distal end side, and the base end opening portion is sealed with an epoxy resin or the like to prevent moisture from entering the inorganic insulating material 102 and deterioration of insulation. . The base end may be provided with a terminal box that accommodates a sleeve that accommodates a connection portion between the thermocouple core wire and the compensation conductor, or a terminal block for connection with the compensation conductor.

  As shown in FIG. 3, the temperature sensing part of the non-grounded thermocouple is in the insulating material, whereas the grounded thermocouple has the thermocouple wire tip connected to the sheath as shown in FIG. The sheath tip is a temperature sensitive part.

  Conventionally, when measuring the surface temperature of equipment such as pipes and containers with a sheathed thermocouple, it has been common to attach a pad as shown in FIGS. 7 and 8 to the tip of the thermocouple and place it on the object to be measured. It was. 8 is a cross-sectional view taken along the line VII-VII in FIG. As shown in these drawings, the sheath thermocouple 106 is attached to the metal plate pad 107 by welding the portion 108a, and this is installed by welding the portion 108b to the measurement object 109.

  As a modification of the pad described above, a pad having a cross-sectional shape shown in FIGS. 9 and 10 may be used. FIG. 9 shows a pad 107 of FIGS. 7 and 8, in which a portion of the thermocouple 106 is notched so that the side surface of the thermocouple sheath is in direct contact with the measurement object, and further, the thermocouple is directed in the direction of the measurement object. By applying force, the cross-sectional shape is flattened, and the contact area between the measurement object and the side surface of the thermocouple sheath is increased.

FIG. 10 shows that the thermocouple sheath side surface is brought into direct contact with the object to be measured by installing the thermocouple 106 inside the pad 107.
Japanese Patent Laid-Open No. 06-129913

  However, according to the above technology, there is a large temperature difference from the ambient temperature of low-temperature pipes and the like through which steam flows, and the installation of heat insulating materials inside the furnaces where fuel burns, such as boilers, heating furnaces in refinery facilities, and incinerators When measuring the surface temperature of a device that cannot be measured, the temperature of the temperature sensitive part is affected by the ambient temperature, resulting in an error in the measured value. In the case of the thermocouple tip pad having the shape shown in FIGS. 9 and 10, heat transfer between the measurement object and the sheath thermocouple tip is promoted compared to the shape of FIG. The measurement error due to the influence is reduced, but the amount of reduction is small and the measurement error does not decrease greatly.

  Therefore, this device is used for a measurement object that has a large temperature difference from the ambient temperature and does not allow installation of a heat insulating material when measuring the surface temperature of equipment such as pipes and containers by a sheath thermocouple. It is an object of the present invention to provide a thermocouple tip pad that does not cause measurement errors due to the influence of ambient temperature.

  In order to solve the above problems, the pad according to the first device has the following structure to protect the thermocouple element from the external environment such as mechanical shock and corrosive atmosphere, and around each thermocouple element. Without detracting from the characteristics of the sheathed thermocouple that ensures insulation of the thermocouple, the thermocouple temperature sensing part was directly in contact with the measurement object, and the part of the measurement object in contact with the thermocouple temperature sensing part was shielded from the atmosphere The sheath thermocouple tip pad is characterized in that the measurement error due to the influence of the ambient temperature is eliminated.

  In the structure, the measurement object and the contact portion of the pad are flat, and surfaces for welding to the measurement object are provided on both sides of the contact surface so as to form an obtuse angle with the contact surface.

  The pad is provided with a thermocouple hole for inserting a sheath thermocouple, and two thermocouple wire holes connecting the contact surface between the hole and the measurement target of the pad. Inserted into the thermocouple hole is a sheathed thermocouple tip that exposes two positive and negative thermocouple wires from the tip, and the two exposed thermocouple wires are two thermocouples. Passed through the center of the hole for each pair of wires, the tip of each wire is located at the pad surface opening of each hole for thermocouple wire, and the pad surface opening of each hole for thermocouple wire is the tip of the thermocouple wire It is hermetically sealed together with the part.

  In addition, the gap inside the thermocouple hole and the thermocouple wire hole is filled with an insulating material, and the opening on the pad surface of the thermocouple hole is sealed with a plug, welding, or the like. The interior is shielded from the outside atmosphere.

  The second device has one thermocouple wire hole in the structure described above, and insulates the surroundings by passing two thermocouple wires one by one through each hole of the two-hole insulation tube. By making this a structure that is inserted into the hole for the thermocouple wire, the thermocouple wire is protected from the external environment such as mechanical shock and corrosive atmosphere, and insulation around each thermocouple wire is ensured. Without impairing the characteristics of the sheathed thermocouple, the thermocouple temperature sensing part is brought into direct contact with the measurement object, and the part of the measurement object that contacts the thermocouple temperature sensing part is shielded from the atmosphere. A sheath thermocouple tip pad characterized by eliminating measurement errors.

  As shown in the previous example of ungrounded thermocouple and grounded thermocouple, if the tip of the positive and negative thermocouple wires is connected, the connection point is the temperature sensor. If the temperature of the connection point becomes the measured value, and the tip of the plus and minus thermocouple strands is connected to a metal such as a sheath and is electrically coupled via the metal, The metal becomes a temperature sensitive part, and the temperature of the metal becomes a measured value.

  In the sheath thermocouple tip pad according to the present invention, between the two thermocouple wires on the plus side and the minus side, if there are two holes for welding material and thermocouple wires, the pad material between the holes, They are electrically connected, and these become the temperature sensing part, but since the pad material between the welding material and thermocouple wire hole is in contact with the object to be measured, the same temperature as the object to be measured And the measured value is the surface temperature of the measurement object. In addition, the object to be measured at the part where the temperature sensing unit is in contact with the pad main body, the insulating material filled therein, and the welding surface provided at an obtuse angle with the contact surface on both sides of the contact surface with the pad object to be measured Since the surface is shielded from the atmosphere by welding the surface to be measured, the temperature is hardly affected by the ambient temperature. As described above, by using the pad of the present invention, the temperature difference from the ambient temperature is large, and the influence of the ambient temperature, which has occurred when measuring the temperature of a device to which no heat insulating material is attached, has been hitherto. The error can be greatly reduced. The reason why the pad welding surface is provided with an obtuse angle of the contact surface with the object to be measured is to facilitate welding.

  In the sheath thermocouple tip pad according to the present invention, the two thermocouple wires exposed from the tip of the sheath thermocouple are housed inside the sealed pad, so that the thermocouple wires are externally attached. In addition, since each thermocouple wire is surrounded by an insulating material, it is protected from the external environment such as mechanical shock and corrosive atmosphere. Insulation between them is ensured. As previously mentioned, sheathed thermocouples have thermocouple wires that are protected from the external environment such as mechanical shocks and corrosive atmospheres, and between the thermocouple wires and between the thermocouple wires and the surroundings. Although it has the feature that the insulation between metals is ensured, the pad of this invention can be used without impairing these features.

  An embodiment of the present invention will be described below in detail with reference to the specific examples of FIGS. FIG. 2 is a cross-sectional view taken along the line II in FIG. 1, and the insulating material 3 in FIG. 1 is not shown in order to facilitate the understanding of the structure.

  The pad body 1 is provided with a thermocouple hole 5 and two thermocouple wire holes 6. The thermocouple hole 5 has two thermocouples on the plus side and the minus side from the tip shown in FIG. A sheathed thermocouple with a pair of strands exposed is inserted. FIG. 5 is a cross-sectional view of this sheath thermocouple. 101 is the sheath of the sheath thermocouple, 102 is the insulating material in the sheath thermocouple, 103 is the positive thermocouple element, 104 is the negative thermocouple element, and 105 is the tip seal Yes. The two thermocouple wires exposed from the tip of the sheath thermocouple are inserted into two thermocouple wire holes 6 respectively, and the tips of the thermocouple wire holes 6 are openings on the pad body surface. Is located. The pad surface opening of the thermocouple wire hole 6 is sealed by welding at the portion 4b together with the tip of the thermocouple wire.

The gaps of the thermocouple hole 5 and the thermocouple wire hole 6 are filled with an inorganic insulating material powder 3 such as magnesium oxide (MgO) or aluminum oxide (Al ₂ O ₃ ). The left end of the hole 5 is sealed by welding the pad plug to the pad cylinder at a portion 4c, and the right end is sealed by welding the sheath 101 to the pad cylinder at the portion 4a. The right end of the pad cylinder is thinned to reduce the heat capacity and facilitate welding with the sheath 101.

In this way, each exposed thermocouple wire is installed in a pad that is shielded from the outside atmosphere and covered with an insulating material, so that external mechanical shocks, corrosive atmospheres, etc. It is protected from the environment, and insulation between the thermocouple wires and between the thermocouple wires and the surrounding metal is secured, and the features of the sheath thermocouple are not impaired. The sheath thermocouple seal 105 is used to prevent moisture from entering the insulating material 102 and deterioration of insulation between the time when the sheath thermocouple is manufactured and the time when the pad is assembled. It is provided and is not necessary when assembling immediately after the production of the sheath thermocouple. Further, when the exposed thermocouple element is inserted into the thermocouple element hole 6, the thermocouple element is made of magnesium oxide (MgO) or aluminum oxide (Al ₂ ) in order to ensure insulation from the hole wall. In some cases, the tube is passed through an insulating tube made of an insulating material such as O ₃ ) and inserted into the thermocouple element hole 6.

  FIG. 2 shows a state where the assembled pad is installed on the measurement object 109. The portion of the pad body 1 that is in contact with the object to be measured is cut into a flat surface in order to ensure contact, and further, for welding that forms an obtuse angle with the contact surface over the entire length in the longitudinal direction on both sides of this surface. A plane is made. The welding surface and the measurement object 109 are welded, and the contact surface of the pad body 1 with the measurement object is in contact with the measurement object 109. The temperature sensing part of the thermocouple is composed of the surface portion of the pad body 1 sandwiched between the two thermocouple element holes 6 and the welding material of the 4b part, both of which are in contact with the measurement object 109. Therefore, the temperature is the same as that of the measurement object 109. In addition, the temperature sensitive part of the measurement object is in contact with the pad main body, the insulating material filled in the pad body, and the pad body, the measurement object 109, and the welding, so that the temperature is the atmosphere. Insensitive to temperature. For this reason, by using the pad of the present invention, the influence of the ambient temperature, which has conventionally occurred when measuring and measuring the temperature of a measurement object that has a large temperature difference from the atmosphere and is not attached with a heat insulating material. The error due to is greatly reduced.

  Table 1 is a measurement example showing the effect of the sheath thermocouple tip pad according to the present invention shown in FIGS. 1 and 2. Measurement using a sheathed thermocouple tip pad according to the present invention shown in FIG. 1 and FIG. 2 with a stainless steel tank having a thickness of 10 mm containing a liquid at 500 ° C. placed in an atmosphere at a temperature of 800 ° C. The result with the measurement using the conventional sheath thermocouple tip pad shown in FIG.7 and FIG.9 is shown. The measurement object temperature in Table 1 is a value measured with a sheathed thermocouple embedded near the surface of the stainless steel bath, and is a value considered as a true surface temperature. From Table 1, it can be seen that the measurement error is 21 ° C. when the conventional sheathed thermocouple tip pad is used, while the error is greatly reduced at 5 ° C. when the pad according to the present invention is used. .

  The present invention is a metal pad that is attached to the tip of a sheathed thermocouple and used for contact with a measurement object in order to measure the surface temperature of the device with a sheathed thermocouple. The surface to be welded to the object to be measured is provided at an obtuse angle with the contact surface on both sides of the contact surface, and a thermocouple hole for inserting a sheath thermocouple is provided in the pad. There are two thermocouple wire holes that connect the contact surface between the hole and the measurement object of the pad, and the two thermocouple wires on the plus and minus sides are exposed from the tip of the thermocouple hole. The tip of the sheathed thermocouple is inserted, and the two exposed thermocouple wires are respectively passed through the centers of the two thermocouple wire holes, and the tip of each wire is connected to each thermocouple wire. The pad surface opening of each thermocouple wire hole is located at the pad surface opening of the hole It is hermetically sealed together with the tip of the thermocouple wire, and the space inside the hole for the thermocouple and the hole for the thermocouple wire is filled with an insulating material. This is a sheathed thermocouple tip pad having a structure in which the opening on the surface is sealed with a plug, welding or the like to block the inside of the hole from the external atmosphere.

  Further, the present invention provides a sheath thermoelectric device having a structure in which one thermocouple wire hole is provided in the above-described structure, and two thermocouple wires are covered with an insulating tube and passed through the thermocouple wire hole. A tip-to-tip pad was used.

  1 and 2 with sheath outer diameters of 6.4 mm and 8.0 mm, and a sheath thermocouple tip pad with a pad length of 40 mm, height of 13 mm, and width of 16 mm has been manufactured. Has been used at a maximum ambient temperature of 1000 ° C.

  Equipment that has a large temperature difference from the ambient temperature, such as low-temperature pipes through which steam flows, and where heat insulation cannot be installed, is measured in boilers, refinery facilities such as heating furnaces and incinerators This is effective when measuring the surface temperature.

It is a longitudinal cross-sectional view of the sheath thermocouple tip pad of this invention. It is II sectional drawing of FIG. However, the insulating material 3 is not illustrated. It is a longitudinal cross-sectional view of a non-grounding type sheathed thermocouple. It is a longitudinal cross-sectional view of a grounding type sheathed thermocouple. It is a figure showing the III-III cross section of FIG. 3, the IV-IV cross section of FIG. 4, and the VI-VI cross section of FIG. It is a longitudinal cross-sectional view of the sheath thermocouple used for the pad of this invention. It is a top view of the conventional sheathed thermocouple tip pad. It is VII-VII sectional drawing of FIG. It is VII-VII sectional drawing of the improved type of FIG. It is VII-VII sectional drawing of the improved type of FIG.

Explanation of symbols

1: Pad trunk 2: Pad plug 3: Insulation material 4: Welded part (4a; Sheath-pad trunk welded part, 4b; Thermocouple element-pad trunk welded part,
4c; pad body-pad plug welded part, 4d; pad body-welded part to be measured)
5: Thermocouple hole 6: Thermocouple wire hole 101: Thermocouple sheath 102: Insulating material 103: Positive side thermocouple wire 104: Negative side thermocouple wire 105: Seal 106: Sheath thermocouple 107: Plate Pad 108: welded part (108a; sheath-pad body welded part, 108b; pad body-measurement object welded part)
109: Measurement object

Claims (2)

  In a metal pad that is used by attaching to the tip of a sheath thermocouple to measure the surface temperature of the device with a sheath thermocouple and making contact with the measurement object, the contact portion of the pad with the measurement object is flat, Surfaces for welding to the object to be measured are formed on both sides of the contact surface at an obtuse angle with the contact surface, and a thermocouple hole for inserting a sheath thermocouple and a hole for inserting a sheath thermocouple are provided in the pad. There are two thermocouple wire holes that connect the contact surface of the object to be measured with the pad, and the thermocouple holes expose the two thermocouple wires, plus and minus, from the tip. The tip of the pair is inserted, and the two exposed thermocouple wires are passed through the center of the two thermocouple wire holes, and the tip of each wire is a pad of each thermocouple wire hole Located at the surface opening, the pad surface opening of each thermocouple wire hole is the thermocouple element. It is sealed together with the tip by welding, and the gap inside the thermocouple hole and the thermocouple wire hole is filled with an insulating material, and further, the opening on the pad surface of the thermocouple hole A sheathed thermocouple tip pad that has a structure in which the inside of the hole is shielded from the external atmosphere by sealing with plug, welding, etc.   2. The structure according to claim 1, wherein a single thermocouple wire hole is provided, and two thermocouple wires are covered with an insulating tube and are passed through the thermocouple wire hole. The sheath thermocouple tip pad as described.

Images