JPS5948333B2 - High-responsive resistance thermometer sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a temperature sensing resistor in which a resistance temperature sensing element is inserted and fixed into an exterior metal tube through an inner tube. By applying pressure from inside or above the outer bond L, the element is crimped and fixed inside the inner tube, and the inner tube is closely fixed to the outer tube, thereby firmly fixing the element, improving heat transfer and heat radiation effects, and improving vibration resistance. It is an object of the present invention to provide a temperature-sensing section of a resistance thermometer that has excellent performance and dynamic response and is less affected by self-heating.

Conventionally, the standard type of resistance temperature detector was one in which the element was fixed in a protective tube with inorganic insulating powder, but with this type, the fixation was incomplete because the powder could not be firmly filled during manufacturing. However, the presence of inorganic insulating powder between the element and the outer tube tends to impede the heat transfer effect and result in a lack of responsiveness. As a result of inhibiting self-heating heat dissipation, measurement errors may occur.

In order to eliminate these defects, the present inventor inserted the device into an elastic metal cylinder having vertical grooves in the longitudinal direction, as previously announced in Utility Model Publication No. 52-39506. However, the present invention is based on the structure of the metal inner tube of the above-mentioned public notice.
The aim is to improve the accuracy and response even further by improving the material. In addition, it is well known that the temperature-sensing part of a rod-shaped resistance thermometer element is not the tip like a thermocouple, but the longitudinal side surface of the element. In the existing conventional type, heat received from outside the tube is transferred to the tube wall and reaches the element located in the core through the insulation powder, which causes a delay in response. When the diameter is large, a large diameter element is inevitably required.

The present invention has been made to eliminate the above-mentioned defects, and its gist is to provide a small hole fitted in the longitudinal direction from the end of an inner tube with good heat conduction fitted into a large-diameter exterior metal tube. The small-diameter element is mounted and fixed in a narrow groove cut or formed in the inner tube or on the tube wall of the inner tube, so that the element is eccentrically fixed with respect to the axis of the large-diameter exterior metal tube.

Result 1: The amount of heat received is limited to the outer metal tube and the hollow thin-walled inner tube wall, so the heat mass is significantly reduced compared to the conventional method. Also, since the small-diameter elements present in the inner tube are close to the measurement object, the temperature of the measurement object is reduced. As a result, the high response is increased by balancing in a short time, and a small diameter element with good response is used for the two large diameter exterior metal tubes instead of using a large diameter element as in the conventional method. A plurality of elements are mounted in opposing positions in the plurality of pores of the three inner tubes, and two series,
It is possible to determine the average temperature for triple elements, 4. Alternatively, it is possible to connect multiple small diameter elements in series or parallel, and 5. It is also possible to install elements at different levels in each of the plurality of pores drilled in the structure, thereby making it possible to use a resistance temperature detector for multi-point measurement of temperature distribution.

That is, the gist of the present invention is that the small-diameter resistance temperature detector element is eccentric to the axis of the large-diameter exterior metal tube and mounted close to the inner wall of the exterior metal tube, and Of course, the pores may be narrow grooves instead of perforations.

The present invention will be explained in detail with reference to explanatory diagrams. Fig. 1 shows a well-known resistance temperature sensor element 1 as a front view, and it shows a glass-encapsulated element, a ceramic-encapsulated element, a mica-type element, etc., which have good electrical insulation properties. It is insulated by a suitable insulator.

The inner tube 2 in FIG. 2 is made of a metal with good malleability and good heat conduction (for example, silver, aluminum, copper, etc.) or a non-metal with good heat conduction and machinability (for example, boron nitride), and has a diameter smaller than that of the element 1. The inner tube 2 has a large thickness and a length slightly longer than the length of the small diameter element 1, and the inner tube 2 has an end portion 3.
A pore 4 having a diameter into which the element 1 can be inserted is bored.

There may be a plurality of pores as shown in 42 in FIG. 3, or one or more pores 4 (
(shown with imaginary lines). Next, one or a plurality of resistance elements 1 are fitted into the narrow holes 4, 4 or the narrow grooves 422 of the inner tube 2, respectively, as shown in FIG. That is,
The inner tube 2 has an inner diameter that allows insertion of one or more elements 1 into one or more small holes 4, 42 or narrow grooves 422 formed in the inner tube 2, and has sufficient mechanical strength as a protective tube. After inserting the chemically strong, thin-walled exterior metal tube 5 from the open end to the bottom, the inner tube 2 is tightly fixed integrally with the exterior metal tube 5 by inserting a metal It is fixed by applying pressure from the inside of the inner tube 2 using a jig, for example, by swaging, caulking, flaring, etc.

In this case, when a metal tube is used as the inner tube 2, the element 1 can be replaced with an outer metal tube without damaging the element 1 fitted in the pore 4 because it is malleable and hollow. 5
It is eccentric to the axis of the exterior metal tube 5 and is installed at a position closest to the inner wall of the exterior metal tube 5, that is, at a position where it is most likely to receive external heat. If the material of the inner tube is a non-metallic tube, the upper end of the inner tube is press-fitted from the open end of the outer metal tube using a jig to tightly fix it to the outer metal tube. However, as the inner tube 2, it is also possible to use a substantially cylindrical body formed by bending an elastic metal plate so as to have narrow grooves 422 in the longitudinal direction on the outer surface.

Since the present invention has the above configuration, as described at the beginning of this paper, the small diameter element 1 with good response is mounted closest to the exterior metal tube 5, thereby reducing the heat mass against heat received from the outer surface. In addition to increasing responsiveness, it is possible to measure the average temperature by mounting multiple elements 1 in opposing positions for double or triple series, and by connecting and mounting multiple elements in series in multiple holes, respectively. For example, it has become possible to connect two 50 ohm elements in series to obtain the same result as one 100 ohm element.

In addition, after cutting or forming fine holes 4, 42 or fine grooves 422 at different levels in the inner tube 2 of a required length and inserting the element 1,
This also makes it possible to obtain a resistance temperature detector for multi-point measurement of temperature distribution using a simpler method than the conventional method of inserting and fixing it into the exterior metal tube 5. The above are examples of the effects depending on the mounting position, but as a result of the inner wall of the exterior metal tube 5 and the inner tube 2 into which the element 1 is inserted are closely integrated, the vibration resistance is increased and the outside of the exterior metal tube 5 is The heat of the measurement object that has received more heat is quickly transferred to the resistance temperature detector element 1 fitted in the inner tube with good heat conductivity, while the self-heating due to the measurement current is radiated through the inner tube 2 which also has good heat conductivity. The present invention eliminates the defects of the conventional method described at the beginning of the article and provides a high-responsive resistance temperature sensing section.

[Brief explanation of the drawing]

Fig. 1 is a front view of the element, Figs. 2 and 3 are perspective views of an example of the inner tube, Fig. 4 is an explanatory diagram showing the assembled state, and Fig. 5 is a perspective view of the inner tube with the elements inserted in different levels. It is. DESCRIPTION OF SYMBOLS 1...Element, 2...Inner tube, 3...End part, 4...
Pore, 42'... Thin groove, 5... Exterior metal tube.

Claims (1)

[Scope of Claims] 1. A small-diameter resistance thermometer element encapsulated with a solid insulator with good electrical insulation properties, which is machined or formed in the longitudinal direction from the end of a metal inner tube with excellent heat conductivity and malleability. A large-diameter exterior metal tube is inserted into the hole and then inserted into the outside of the inner tube, and the resistance element is positioned eccentrically with respect to the axis of the exterior metal tube, and the inner tube and the exterior metal tube are brought into contact with each other to enable heat transfer. A temperature-sensing part of a resistance thermometer with an element placed close to the inside of an exterior metal tube. 2. The high-responsive resistance thermometer thermosensor according to claim 1, wherein the exterior metal tube and the metal inner tube are integrally and closely fixed by applying pressure from the outside of the exterior metal tube or the inside of the metal inner tube. 3. The high-responsive resistance temperature sensor temperature-sensing unit according to claim 1, wherein the metal inner tube has a hole cut therein and one or more elements are attached to the hole. 4. Claim 1, wherein one or more thin grooves are cut in the outer wall of the metal inner tube, and one or more resistance temperature detector elements are installed in each of the narrow grooves. Highly responsive resistance thermometer sensor. 5. Claim 1, which is formed by connecting elements in series or parallel to be fitted into and fixed in the pores or narrow grooves of the metal inner tube.
The high-responsive resistance thermometer temperature-sensing section described in . 6. The high-responsive resistance thermometer thermosensing section according to claim 1, wherein elements are mounted in pores or narrow grooves of a metal inner tube of a required length at different levels in the longitudinal direction of the tube. 7. The high-responsive resistance thermometer according to claim 1, which uses as an inner tube a substantially cylindrical body formed by bending an elastic metal plate so as to have narrow grooves in the longitudinal direction on its outer surface. Department.