JPS5814965B2 - How to close a thermocouple covered with synthetic resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for closing a thermocouple tip coated with a synthetic resin.

Conventionally, thermocouples have had wires housed inside a metal sheath with an electrical insulator such as magnesium oxide interposed, but recently thermocouples have become cheaper and easier to bend when buried in crude oil tanks. Thermocouples whose wires are coated with synthetic resin are often used because they are easy to work with, do not corrode, and can withstand many years of use.

By the way, the tip of a thermocouple coated with this synthetic resin is often used to seal it, but the conventional method of closing the tip is a very complicated process, the quality is not sufficient, and the appearance is also poor. It was bad.

Therefore, the present invention was proposed to solve these problems.

The present invention provides a thermocouple in which a wire is coated with a synthetic resin,
Cut off the tip of the synthetic resin coating, connect the strands, cover the exposed strands with a tubular synthetic resin lid with a groove in the axial direction, and insert the lid into the bottomed hole of the heated closure. This is a method of closing a thermocouple covered with synthetic resin, in which the tip covered with material is inserted and pushed until it touches the bottom of a machined hole, thereby sealing the tip.

The present invention will be explained below based on an embodiment shown in the drawings.

FIG. 1 shows a thermocouple in which wires 3, 3' are covered with a synthetic resin coating 1 with glass fibers 2 interposed therebetween.

FIG. 2 is a side view of FIG. 1. The thermocouple wires 3, 3' are coated with electrically insulating synthetic resins 4, 4'.

The glass fiber 2 is interposed to form a round cross-section of the thermocouple, and its outer periphery is bound with Teflon tape (not shown) to facilitate handling of the thermocouple.

For the synthetic resin coating 1, a heat-softening resin such as Teflon tetrafluoride, Teflon 4.6 fluoride or Teflon trifluoride is used.

In order to connect the thermocouple wires 3 and 3', the coating 1 and the glass fiber 2 at the tip of the thermocouple are cut off as shown in FIG.

The cutting length Ll is the shortest 3 to 5II, and the diameter of the thermocouple (
It is about 5m long).

Next, the ends of the synthetic resins 4, 4' covering the wires 3, 3' are slightly cut off, and the wires 3, 3' are connected 5 by welding or brazing.

The lid material 6 is made of the same material and the same diameter as the covering 1, has a cut groove T in the axial direction as shown in FIG. 4, and has a length L2 of about 10 mm.
It is a tubular body (about twice the diameter).

This cover material 6 covers the cut away and exposed thermocouple wires 3, 3'.

Further, the closing tool 8 includes a machined hole 9 with a bottom that is slightly larger in diameter than the outer diameter of the lid member 6, and the machined hole 9 is formed to have a thin wall.

The tip portion covered with the lid material 6 is inserted into the machined hole 9, and at the same time, the machined hole 9 is heated to 200 to 300°C with a heater.
Push it in until the tip 6a contacts the bottom 9a of the machined hole 9.

Then, the lid member 6, the coating 1, and the cut groove 7 are welded together by heating, and the tip is sealed 10 as shown in FIG.

Note that after fitting the lid material 6 into the processed hole 9, the exposed wires 3, 3
' may be inserted into the lid material 6.

Since the processed hole 9 is thin, it can be heated easily and cooled quickly.

Note that the cut groove I of the lid material 6 is used to fit the lid material 6 and the coating 1 into the machined hole 9 of the closure tool 8, and when heating and melting, removes the air layer remaining in the machined hole 9 to the outside. In addition, the outer diameter of the coating 1 varies slightly depending on the lot, but this is to provide dimensional flexibility.

The present invention is a method of closing a thermocouple coated with a synthetic resin, the tip of which is cut off, covered with a wire covered with a lid material, and inserted into a machined hole of a heated closure and pushed in to seal the tip. So,
Closing the lid is extremely easy.

Additionally, since the resin is welded by heating, the tip is completely closed and the quality of the seal is improved.

Furthermore, since the closing lid and the covering are made of the same material and have the same diameter, and the joints are not visible due to heat welding, the external appearance is also good.

The lid material has a cut groove, so when the lid material and coating are inserted into the machined hole of the closure and heated and melted, the air layer remaining in the machined hole can be removed to the outside, and the outer diameter of the coating can be removed. Dimensions vary slightly depending on the lot, but dimensional flexibility is possible.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a synthetic resin coated thermocouple according to the present invention, FIG. 2 is a side view of FIG. Vertical cross-sectional view of the pair, 4th
Figure 5 is a perspective view of the lid according to the present invention, Figure 5 is a sectional view showing the tip covered by the lid inserted into the closure, and Figure 6 is the lid with the tip sealed according to the invention. Thermocouple coated with synthetic resin. 3.3'...Element wire, 1...Synthetic resin coating,
5... Connection, 7... Cut groove, 6...
- Lid material, 8...Closing tool, 9...Processed hole, 9a...Bottom of processed hole, 10...Seal.

Claims (1)

[Claims] 1. In a thermocouple whose wire is coated with a synthetic resin, the tip of the synthetic resin coating is cut off, the wire is connected, and the exposed wire is covered with a tubular synthetic resin lid having a groove in the axial direction.
The tip covered with the lid material is inserted into the bottomed machined hole of the heated closure and is pushed in until it contacts the bottom of the machined hole to seal the tip, coated with synthetic resin. How to close a thermocouple.