JPS62157527A - Sensor device for measuring physical parameter - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention comprises a sensor element within a capsule and an electric wire extending inside a tube sealed in the capsule and connecting to a control circuit, wherein the capsule and tube are The present invention relates to a sensor device for measuring physical parameters made of metal.

(Prior art) This type of well-known sensor device (DB-OS N12337
In 035), a straight metal tube closed at one end and provided with a threaded bushing at the other end has at least one tube in its closed end region.
It houses two temperature-dependent resistors which are connected via electrical wires to plug pins or other terminals in the bushing area. The area of the metal tube that accommodates the resistor is filled with a thermally conductive paste, and the remaining interior is filled with casting resin, like the bushing. Temperature sensors are used particularly in open-pit mines to monitor the temperature of underground explosive gases and gases and liquids in potentially explosive chambers.

- (Problem that the invention seeks to solve) However, such sensor devices are not flexible.

Since it uses a straight metal tube, it can only be used in a few applications. Initially, the sensor element is protected from influences by the surrounding atmosphere by a resin filling. However, if conditions within the measurement chamber are not satisfactory, moisture can reach the sensor element due to capillary action and diffusion, reducing its service life. The above tendency is especially pronounced if the closed end is cooler than the opposite open end (and the measuring chamber has a humid atmosphere.The moisture builds up in the sensor area, which causes a kind of pumping effect towards the sensor area. In addition, the electric wires extending outward from the pipes are also susceptible to corrosion.

The problem to be solved by the invention is to provide a sensor device of the type mentioned above which is easier to apply than before for a wide range of individual applications and which has a longer service life.

Means and Effects for Solving the Problems The above problem is solved according to the invention by providing a tube made of metal and having a small diameter such that it can be bent by hand into the desired final shape, and opposite to the sensor element. This is achieved by providing a closing element at the side tube end, so that the interior of the capsule and tube is hermetically sealed to the outside.

In this configuration, the Mensa device is manually bendable. For each application, therefore, the capsule and the sensor element can be arranged at the measurement point and the tube containing the conductor can be adapted to the shape of the measurement chamber. That is, since the tube can be removed from the measurement chamber at the desired point, there is no risk that the wire will be influenced by the atmosphere in the measurement chamber at the point where it exits the encapsulation. An internal hermetic seal ensures that moisture does not reach the sensor element even after prolonged use. Hermetic seals also eliminate the need for sealing fills inside capsules and tubes. Therefore, it is easier to bend the tube by hand.

The tube should be relatively long, preferably between 0.5 m and 5 m, more preferably between 1 m and 2 m. This allows the tube to be pulled out of the measurement chamber and guided to any desired point in virtually any application. Once formed, it can be shortened at any time, so there is no harm done.

Since the tube only accommodates the conducting wire, it can have a very small outer diameter, preferably from 211 to 4 m, preferably about 3 mm.

With a diameter of this size, even metal tubes can be bent by hand very easily.

In a preferred embodiment, the tube is a capillary tube.

Such capillary tubes are still used in thermostatically controlled valves to transmit vapor pressure from a temperature sensor to the valve's operating bellows. These tubes can be easily bent. Also, the inner diameter is sufficient to accommodate the required R-km.

The capsule and tube can be made in one piece, but this need not be the case. In many cases, it is preferred that the capsule has a larger diameter than the tube, and these two separately made parts are interconnected by a hermetically sealed seam.

This allows conventional sensor elements to be used in combination with bendable metal tubes very easily.

In most cases it is desirable for the closing element to have an electrical outlet with at least one pole. This directs signal or power current through the walls of the hermetic encapsulation structure. In the case of a unipolar lead terminal, the second conducting wire can be formed of capsule metal. Alternatively, the current can also be transmitted by a transformer.

In one embodiment, the closure element consists of a metal ring applied to the end of the metal tube with a hermetic seal surrounding the fusible glass insert through which at least one piercing pin passes. In this way, the lead terminal can also be manufactured with relatively small dimensions.

Particularly advantageously, the closing element is a housing containing the control circuit. Therefore, the sensor signals can also be evaluated within the capsule. The control circuitry is also protected by a hermetic seal, resulting in a long service life whether the housing is placed inside or outside the measurement chamber.

Preferably, the control circuit comprises a desired value setting device which can be actuated via a hermetic closure wall of the housing. This activation can be performed, for example, using an electrical outlet terminal. Alternatively, the desired value setting device may consist of a magnetic field detector which can be actuated by a magnet outside the housing, or at least one radiation-sensing element arranged outside the housing and into which radiation from a light source can be incident. You can also.

The interior may be evacuated or filled with a protective gas such as nitrogen. This provides greater protection.

A preferred application of the sensor device is when it is used to measure humidity in a humid measurement chamber, in particular a refrigerator or a freezer, in which the sensor element is arranged within said chamber and the closure element is arranged outside the chamber. The hermetic encapsulation ensures that the humid atmosphere within the survey chamber does not reach the sensor element and the conductors. especially,
There is no risk of moisture entering the capsule during dewatering or of the capsule bursting due to ice that forms when the temperature suddenly drops below 0 degrees Celsius after deicing.

Hereinafter, preferred examples of the present invention will be described in detail with reference to the drawings.

EXAMPLE The sensor device of FIGS. 1 and 2 consists of a metal capsule 1 containing a sensor element 2. The sensor device of FIGS. Sensor element 2 is a temperature sensor, in particular a temperature-dependent resistor. The sensor element 2 may also be responsive to other physical parameters, such as pressure, magnetic flux, mechanical vibrations, radiation fields, etc., in which case the metal of the capsule is selected accordingly. In the thin metal tube 3 leading to the capsule 1 extend two electrical wires 5.6 which connect the sensor element 2 to the two pins 7.8 of the output terminals 90. The outlet terminal 9 is provided at the opposite end of the metal tube 3 and forms part of the closure element 10 . The closing element 10 has a cross-sectional ring 11 and a fusible glass insert 12 surrounding both pins 7 and 8.

The closure element 10 of the output terminal may be a readily available component. The closure element 10 is hermetically sealed to the metal tube 3, for example by soldering, welding, gluing or the like. The interior 13 of the metal capsule 1 and metal tube 3 is evacuated and then filled with nitrogen.

The metal tube 3 has an outer diameter of 3 mm and an inner diameter of 2 mm.

The length of the metal tube 3 is between 0.5 m and 5 m, and in this example is 1.5 m. The material of the tube is brass.

Metal tubes have already been manufactured for thermostand temperature control valves.

It is a normal capillary tube. This kind of metal tube is
Easily bent by hand into any desired shape.

Due to the hermetic encapsulation, external air, such as humid air, has no effect on the sensor element 2 and the electric wire 5.6. Since the metal tube 3 is long, the extraction terminal 9 can be placed outside the actual measurement chamber, and the electric wire led out to the outside will not be adversely affected by the atmosphere of the measurement chamber.

In the embodiment of FIG. 3, identical parts are designated with the same reference numerals as in FIGS. 1 and 2, and similar parts are designated with reference numbers in the 100s in both figures. Closing element 110 consists of a metal housing 14 surrounding electrical control circuit 15 . Control circuit 15 is mounted on plate 16. The control circuit 15 is also connected on one side to the line 5.6 and on the other side to the line leading to the extraction terminal 109 on the side wall of the housing 14. In this position, a current source can be connected and a measurement signal representative of the parametric characteristic measured by the sensor element 2 can be obtained.

At the interface point between the metal tube 3 and the outer wall 17 of the metal housing 14 there is a joining seam 18 providing a hermetic seal. Various embodiments of the joining seam 18 are shown in FIGS. 4-6. In FIG. 4, the metal tube 3 has an end flange 19, which is joined face-to-face to the outer wall of the housing 14. In FIG. 5, the metal tube 3 has a bead 20 made by swaging and expanding, and this is joined to the outer wall 17. In FIG. 3, the outer wall 17 includes a passage 21,
An undeformed metal tube is inserted into this passage 21. Suitable bonding materials 22 include weld metal, solder, or special plastic adhesives.

In each of the embodiments of FIGS. 7-9, the housing 114.214
and 314, the control circuits 115, 215 and 315 each consist of an externally adjustable desired value setting device. 7th
In the figure, the plate 116 supports a magnetic field detector 131, for example a Hall generator, which can be actuated by a magnet 132 which is displaceable outside the housing. In this case, the housing 114 must be permeable to the magnetic field. In FIG. 8, the desired value setting device consists of a radiation sensing element 231 in the form of a photoswitch or a phototransistor, which element 231 can be emitted by a radiation source 232 in the form of a light emitting diode through a hermetically sealed window 233. be. In Figure 9,
A metal housing 333 of a phototransistor 331 is hermetically sealed to the housing wall by welding and is also emissible by a light emitting diode 232. By providing four such radiation sensing elements, it is possible to switch between 16 different desired settings by appropriate coding.

FIG. 1θ shows that the capsule 1 for the sensor element 2 is closed by crushing and soldering the metal tube 3 at its front end 23.
01 is shown as an example in which it can be formed extremely easily.

In FIG. 11, the metal tube 3 is placed in contact with the large-diameter metal capsule 1, and these parts are interconnected with a hermetic seal by an annular joining seam 24. More specifically, joining seam 24 is a welded seam.

Although the temperature-dependent sensor element 2 has been illustrated above, the first
Figures 2 and 13 show pressure-sensitive sensor elements. 1st
In FIG. 2, a strain gauge 402 is attached to a diaphragm 434 that closes the capsule 401. When diaphragm 434 bends under external pressure, strain gauge 402
The value of changes.

In FIG. 13, the pressure sensitive sensor element is a silicon transducer 502, which has a fixed wall 536 and a diaphragm 53.
4 in a space filled with silicone or silicone oil 535.

When external pressure is applied, this pressure is transmitted to the sensor element depending on its magnitude.

Suitable materials for metal tubes are stainless steel, copper, brass, etc.

Adhesives or ultrasonic welding can also be used when making the connections shown in Figure 4 using plastic tubes, or when closing the tube ends by crushing them (Figure 10).

FIG. 14 shows a refrigerator 25 with a cooling chamber 26 arranged within a thermally insulating housing 27 and accessible via a thermally insulating door 28. FIG. An evaporator 29 is present in the cooling chamber 26 and an encapsulated vapor condenser 3
Refrigerant from 0 is fed to the evaporator via a condenser (not shown). The sensor device of FIG. 3 is installed in such a way that the metal capsule 1 containing the sensor element 2 is located adjacent to the evaporator 29 . A metal tube 3 with electrical wires extends through a sealed aperture 31 in the housing 27. A metal housing 14 containing control circuitry is attached to the rear wall of the refrigerator 25. Here, only the connections between the control circuit 15, the mains power supply and the steam condenser need be made. Of course, the refrigerator may have different configurations other than those illustrated, such as for commercial and store use.

Almost any method common to refrigeration systems having hermetically encapsulated vapor condensers can be used to close the hermetic seal.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a first embodiment of the sensor device according to the present invention; FIG. 2 is an enlarged sectional view of the closed end; FIG. 3 is a schematic diagram of the second embodiment; FIG. 4 is a metallurgical diagram in FIG. FIG. 5 is an alternative to FIG. 4; FIG. 6 is another alternative to FIG. 4; FIG. 7 is as desired A partial sectional view of a housing showing one embodiment of the value setting device; FIG. 8 is a diagram showing a second embodiment of the desired value setting device; FIG. 9 is a diagram showing a third embodiment of the desired value setting device; 1θ diagram shows the first embodiment of the metal capsule for the sensor element; FIG. 11 shows the second embodiment of the metal capsule for the sensor element; FIG. 12 shows the third embodiment of the metal capsule for the sensor element. FIG. 13 is a diagram showing a fourth embodiment of a metal capsule for a sensor element; and FIG. 14 is a schematic sectional view of a refrigerator. 1;101;401;501- Capsule, 2;402
; 502--Sensor element, 3-Pipe, 5.6--Electric wire, 7.8--Pin, 9:109--Output terminal, 10.110--Closing element, 11--Ring, 12-Glass insert, 13-.-Interior, 14; 114; 214;, 314-Housing, 15;
115; 215; 315 --- control circuit, 24--
Sealing seal, 25--refrigerator (freezer), 26--cooling room, 131-magnetic field detector, 132--magnet, 231; 331--radiation sensing element, 232; 332--1 radiation source. Engineering C Tsu 1 0)-s Curvature-1 bet U-σ

Claims (1)

[Claims] 1. A sensor for measuring a physical parameter, comprising a sensor element in a capsule and an electric wire extending inside a tube sealed in the capsule and connecting to a control circuit, wherein the capsule and tube are preferably made of metal. A device consisting of metal and having a small diameter such that the tube (3) can be bent by hand into the desired final shape, with a closure element (10) at the tube end opposite the sensor element (2);
110), wherein the capsule (1; 401; 501) and the inside of the tube (13) are hermetically sealed from the outside. 2. Claim 1, characterized in that the tube (3) has a length of 0.5 m to 5 m, preferably 1 m to 2 m.
The sensor device described in Section 1. 3. The tube (3) is 2 mm to 4 mm, preferably about 3 mm.
3. The sensor device according to claim 1, wherein the sensor device has an outer diameter of . 4. The sensor device according to any one of claims 1 to 3, wherein the tube (3) is a capillary tube. 5. The capsule (1) has a larger diameter than the tube (3) and these two separately made parts have a hermetic sealing seam (
24) The sensor device according to any one of claims 1 to 4, characterized in that the sensor device is interconnected by 24). 6. The sensor device according to any one of claims 1 to 5, characterized in that the closing element (10; 110) is provided with at least a single-pole electrical outlet terminal (9; 109). 7. The closure element (10) has at least one through pin (7
, 8) consists of a metal ring (11) applied to the end of the metal tube (3) with a hermetic seal surrounding a fusible glass insert (12) passing through it. The sensor device according to item 6. 8, the closure element (110) is connected to the housing (14; 114;
214; 314), the inside of the housing is hermetically sealed to the outside, and the control circuit (15; 11
5; 215; 315). The sensor device according to any one of claims 1 to 6. 9. The control circuit (115; 215; 315) is provided with a finding value setting device that can be activated through the hermetic sealing wall of the housing (114; 214; 314). sensor device. 10. Sensor according to claim 9, characterized in that the desired value setting device consists of a magnetic field detector (131) actuable by a magnet (132) arranged outside the housing (114). Device. 11. The desired value setting device is connected to the housing (214; 314
10. Sensor arrangement according to claim 9, characterized in that it consists of at least one radiation sensing element (231; 331) into which radiation from a radiation source arranged outside the radiation source is incident. 12. The sensor device according to any one of claims 1 to 10, characterized in that the inside is evacuated. 13. Sensor device according to any one of claims 1 to 12, characterized in that the interior (13) is filled with a protective gas. 14. When used to measure the temperature in a humid measurement chamber, in particular a refrigerator or freezer (25), a sensor element (2) is arranged in said chamber and a closure element (1
10) is arranged outside the chamber.
A method of using the sensor device according to any one of items 1 to 13.