KR830001272B1 - Solenoid resistance thermometer - Google Patents

Abstract

A solenoid resistance thermometer to contain a temperature sensor forms an electric conductive path on the surface of cylindrical tube which is made of non-conductive material. The electric conductive path is the layer of glass material to characterize an electric conductive phase and is formed to a zig-zag.

Description

Solenoid resistance thermometer

1, 2, 3, 4 and 5 show cylindrical tube substrates each having a conductive passage of a different type.

The present invention relates to an electrical resistance element suitable for use as a temperature sensing element of a thermometer and a resistance thermometer including the same.

Our U. S. Patent No. 3,781, 749 describes an electric resistance element suitable for use as a temperature sensing element of a resistance thermometer composed of a layer of fused glassy material, to which electroconductive fine particles are added and molded using an electrically nonconductive material as a substrate. A further feature described in U.S. Patent No. 3,781,749 is a resistance having a process of mixing a powdered glass material with a dispersion layer of electrically conductive fine particles with an organic material on the surface of an electrically nonconductive substrate, extracting the organic medium by heating, and fusing it into glass. A method of manufacturing an electrical resistance element used for a temperature sensing element of a thermometer is described.

In previous technologies, nonconductive substrates were made of alumina sheets or other heat resistant materials. In another example, the device consists of a plurality of dense layered sheets of fused glassy material separated by a dielectric interlayer, becoming a multilayer plate. Adjacent layers of fused glassy material are interconnected, for example, to form a sinuous electrical conductive path at one end.

Since the temperature sensing element of the known resistance thermometer is formed of a plate and formed of a multi-layered plate, the manufacturing process is complicated and requires high technology in manufacturing. This occurred a lot and was very uneconomical.

The present invention, which has improved and corrected the above drawbacks, is a conventional electrical resistance device for use as a temperature sensing element of a resistance thermometer, and has traditionally been used on the outer or inner surface of a tubular or cylindrical substrate made of an electrically nonconductive material. The conductive path is composed of a single layer of fused glass material having an electrically conductive face.

The electrically conductive path is a undulating, serpentine, spiral or zigzag path, and the substrate is in the shape of a cylindrical tube.

Non-conductive tubular or cylindrical substrates are made of ceramic materials such as alumina or other heat resistant materials. Alternatively, the substrate may be part of the surface of the subject requiring temperature measurement.

The electroconductive face may be formed of granules, fine particles, powders, flakes or microplates and may be selected from the group consisting of gold, silver, platinum, palladium, rhodium, iridium, ruthenium, iron, cobalt, nickel and copper or the like. It is made of the above metals. By suitably adjusting the air conditions in the combustion treatment of the glassy material fused into the non-conductive substrate, various metals can be suitably blended as conductive paths depending on the oxidation characteristics of the metals. The preferred metal used here is platinum. The shape of platinum we like to use is a small piece of challenging particulates. However, if desired, the conductive face may have other shapes as described above, and if powder is used, it may be molded using deposition or grinding techniques.

The layer is suitably blended with platinum flakes and a suitable dispersion of powdered glass or meta-raising ink to the organic medium and heated to remove the organic medium and fusing the glass powder to form a layer on the non-conductive substrate.

The ink or dispersant is screen-printed on the cylindrical substrate surface in the form of a spiral coil by an inductive winding or an inductive winding. Good type is good lottery ticket ship.

Another example of spiral coil formation can be obtained by spiral cutting by lathe.

As described above, the inductive winding body can be easily processed by spiral printing by screen printing or lathe on the cylindrical substrate surface.

Another deposition method of dispersing conductive fine particles on a non-conductive substrate is spraying with or without a mask and spraying with or without a mask.

After combustion, the conductive film is cut using a laser beam or a polishing machine to remove the film portion to form a conductive film of a desired type. However, other methods known in the art, such as air polishing and laser beam, may be used.

Another modified method of dispersing non-conductive conductive particles is to use the screen printing transfer method according to British Patent No. 1,232,577, which describes the application of a phosphorus (p) particulate and a glass powder mixture to a substrate. In one preferred embodiment, the burned organic medium forming the transfer body leaves the finished product of the pre-printed conductive passageway and the transfer body is oxidized. This method is particularly well suited for curved surfaces such as cylindrical and tubular non-conductive substrates.

Embodiments of the present invention will be described below with reference to the accompanying drawings.

A suitable method for promoting meta-izing inks on substrates by association of printing techniques and platinum flakes is as follows.

This method provides a dispersion of the glass flakes inside and outside the platinum flakes and ethyl cellulose, and then the bidispersion is pulverized in a three-stage roll mill until the particle size becomes 6 microns or less.

The composition may be replaced with 1 to 10 grams of methanol in place of carbitol acetate thinner in a manner that metastasizes the substrate by deposition instead of printing. In this case, methanol is added after the roll milling process. The purpose of adding methanol after the powdering process is to avoid unnecessary evaporation.

If it is necessary to apply the metaizing composition by spraying, the composition is modified again by replacing it with methanol with a suitable solvent and coagulant. Referring to FIG. 4, a cylindrical tube alumina substrate (2) in which a layer of a meta- sizing composition containing butyl carbitol acetate thinner is produced as a sublayer (3) of continuous conduction of constant thickness to produce an electrical resistance thermometer element by printing. It is printed on the outer surface 1 of by screen printing technique. As described in British Patent No. 1,415,644, after printing, the substrate is first dried by infrared radiation and then sintered at a temperature in the range of 750 ° to 1300 ° C. Particularly good results are obtained by sintering at temperatures of 1000 ° to 1200 ° C. for 1 to 4 hours and then at temperatures of 750 ° to 1300 ° C. for 1/2 to 8 hours.

4 shows a sublayer 3 of a spiral orbital conductivity produced by any known method. One method of forming a spiral orbit can be formed by mounting a printing substrate on a lathe and applying a thread cutting technique to a lathe carrier instead of a tool with a grinding wheel or disc. In other words, the shelf carrier is supported on the lead screw and thus causes the grinding wheel or disk to move parallel to the longitudinal axis of the workpiece. In operation, the ends of the metallized tube are electrically connected to an ohmmeter that continuously indicates the resistance of the conductive layer and the portion of layer 3 leaves a spiral uncut portion of the layer. Thus, successive indications of resistance give useful information to the operator and stop the helical orbiting once a certain resistance is reached. If necessary, the circuit operation may be designed so that the machining is automatically stopped when the resistance reaches a predetermined value. FIG. 5 is essentially similar to the embodiment of FIG. 4 but provides a non-inductive device having a double helical passageway. FIG. 5 uses two suitably separated disks instead of the single disk used in FIG. 4 to form a double spiral orbit.

When the meta-rising composition is coated on the substrate by immersion coating, the rate of removing the substrate from the bath containing the composition is about 2 cm per minute. This extraction speed results in a relatively uniform coating, which must be slowly rotated when the final coated substrate is dried to produce a uniform thickness.

1, 2 and 3 show different passages, while FIG. 3 shows an arrangement of rewind and induction. Although FIGS. 1, 2 and 3 are shown as occupying about one half of the substrate surface as the conductive passages, this is merely to illustrate the embodiment and to make the best use of the applicable surface area in practice. Will be produced.

In each embodiment, the metagassing is such that the layer 3 is continuous up to the tubular substrate end.

By continuing the metalatizing layer to the end of the substrate it is possible to provide a conductive connection to the device of the invention. In the embodiments of FIGS. 1-5, meta-raising is shown as a substrate single concentric bore, but meta-raising can also be processed into the bore. In this case, one end of each conductor may form a bead in the form of hermetic fitting in the metabolized bore. A bead part is inserted at the opposite end of the boa, and then filled with a meta-raising composition to allow the beads to be bonded, dried and sintered, and finally an electrical connection is established. The bead portion may be formed of a solid piece of a conductive material or may be formed by winding a coil at the end of the conductor. The electrical connection of the conductor is made to increase the area of the conductive passage as shown in FIGS.

If desired, the substrate may be constructed with two or more bores or with a conductive passageway on the surface of the bore. In addition, in the case where it is desired to wire the conductor from one end of the conductor to the device, as described above, one wired side of the conductive passage can be supplied to the place to be connected at a distance through the bore.

The temperature sensing device according to the present invention exhibits a stable resistance coefficient. For example, using a cylindrical tube-like substrate with a length of 25 mm, a diameter of 3 mm and a platinum conducting path having a resistance of 100 ohms at 0 ° C, a resistance temperature coefficient of 0.38 / ° C is obtained. Moreover, these properties were found to remain constant within tolerance after 2000 hours of treatment at 500 ° C. and after a rapid temperature cycle change from room temperature to 600 ° C., i.

The following table shows the change in [Ro (Standard) = Ohm] for the specified temperature and duration.

The periodic stability of the device, expressed as thermal shock resistance, is indicated by the following test results.

As a result, we can see that it is within the tolerances defined in the British standard BS 1094 "Industrial Platinum Resistance Thermometer Element" and the German standard DIN 43760. The following table shows the tolerances obtained by the three devices A, B and C by the present invention.

The concentration of the toxic metals was measured after toxicity test by soaking the device according to the present invention in 50 acetic acid for 24 hours. The results were obtained below the allowable limits for beverage containers of lemon and were as follows.

Lead 3.5p.pm

Cadmium 0.05p.p.m

Zinc 1.6p.p.m

After the conductive layer 3 is formed and sintered to form the conductive passage 4, the devices are completed by coating with a protective film made of glaze compotition. The photoactive agent is preferably a composition comprising glass and ceramic material which does not dissolve at a temperature of, for example, 750 ° C., the temperature used in the device.

The electrical sensing element of the cylindrical resistance thermometer obtained by the same method as described above is extremely easy to manufacture compared to the conventional flat plate or multi-plate type, and the precision resistance value can be provided in manufacturing, and thus the defective product generation rate is minimized. And thus provide a very economical cylindrical electrical sensing element.

We can see that the resistance element manufactured according to the present invention is useful as a temperature sensing element of a resistance thermometer necessary for measuring a rapidly changing temperature in a gas flow such as, for example, an exhaust gas flow.

The temperature sensing device according to the present invention can be used for temperature difference metering for superheat alarm devices, internal combustion engine fuel injection control devices or other fuel drive engines as described in co-pending patent application 46591/73.

Claims (1)

In a solenoid resistance thermometer comprising a temperature sensing element formed on the surface of a cylindrical substrate made of an electrically nonconductive material to sense a temperature change, the electrically conductive passage is fused including an electrically conductive face. A solenoid resistance thermometer comprising a zigzag shape as a layer of glass material.

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