JPH02128127A - Immersion electronic thermometer - Google Patents

Abstract

PURPOSE: To miniaturize a thermometer and at the same time improve reaction speed by forming a covering means that is a housing using a mechanically strong insulation material that has a high heat conductivity and cannot be damaged easily by a medium. CONSTITUTION: An electronic thermometer has a screw mounting stand 1, a tubular housing 2 that is inserted into a medium to be measured being engaged to the stand 1. and a temperature sensor 3 being provided in the housing 2. The temperature sensor 3 is electrically insulated from the medium to be measured, contacts the medium to be measured through the housing 2 so that heat can be transferred, and at the same time the temperature sensor 3 has a sensor element 4 made of a semiconductor and an electrical connection wire that reaches the mounting stand 1 through the housing 2. Then, the housing 2 is a covering means that is directly placed on the sensor element 4 and a connection wire 5, exposes only the connection terminal of the connection wire 5, is made of an electrical insulation material with improved thermal conductivity, and cannot be damaged due to a medium to be measured and is mechanically strong.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an immersion electronic thermometer, and more particularly, to an immersion electronic thermometer, which preferably has a screw-type mount and a preferably tubular mount that fits into the mount and is used to hold the medium to be measured. (hereinafter simply referred to as "medium"), and a temperature sensor disposed in the housing, the temperature sensor in the housing being electrically insulated from the medium and transmitting heat. The temperature sensor relates to an immersion electronic thermometer which is in contact with the medium through the housing and has a sensor element, preferably made of a semiconductor, and a connecting line that passes through the housing and reaches the mounting base.

Problems to be Solved by the Prior Art and the Invention Various types of immersion electronic thermometers have been known for a long time (Lu
eaer, Lexikon der Techn
ik, vol, 4. Lexikon der
Feinwcrktec-hnik L-Z,
DVA, 5tuttaart 1969゜at″T
hermometer” and WiderS
tandSthQrm0+10ter''. In an immersion thermometer, a housing having a temperature sensor inside is inserted into a medium and brought into contact with the medium to transfer heat.

The conventionally known immersion thermometer (l
ueger, IOc, cit, , Wida
An elongated rod-shaped temperature sensor is held in an insulating duplex, which is installed in a tubular metal housing, one end of which is closed, and the other end is fixed to a mounting base. This insertion tube reaches up to the insulating circular head plate of the mounting base, where the terminals for the temperature sensor connection wire are installed.The sensor element of the temperature sensor is a metal resistor with a positive temperature coefficient, a negative A semiconductor resistor with a temperature coefficient of , or a thermal lightning couple, or the like can be used.

Known immersion thermometers have considerable mechanical strength because the tubular housing is made of metal and each temperature sensor is itself further protected by an internal insulating insertion tube. However, due to such a design, the conventional immersion temperature i1 is firstly quite large and secondly prone to swelling. An even bigger problem is that the detection time is relatively delayed. This is due firstly to the fact that less heat is transferred from the medium to the sensor element, and secondly to the large heat capacity j of the housing, insertion tube and temperature sensor itself.

A compact, fast-response, and economical immersion thermometer has been desired in many fields, especially in the field of electronic mill temperature controllers (thermostats) for mixed water supply equipment. This requirement was not met by the well known immersion thermometers or similar immersion thermometers.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an immersion electronic thermometer that is particularly compact, economically manufactured, has a very fast reaction rate, and is suitable for use in electronic thermostats for mixed water supply equipment. .

Means and Effects for Solving the Problems The immersion electronic thermometer of the present invention that achieves the above objects is a covering means in which the housing is placed directly over the sensor element and the connection wire, exposing only both terminals of the connection wire. , which is characterized by being made of an insulating material that has high thermal conductivity, is not susceptible to damage by media, and is preferably mechanically strong. According to the present invention, modern protective materials used in a large number of fields have increased mechanical strength, eliminating the need for a two-layer construction of the insertion tube and housing as in the prior art. For the temperature sensor, a housing made of insulating material is sufficient.

According to the invention, this single housing is placed directly on the sensor element and the connecting line as a current-carrying means and covers the sensor element and the connecting line separately. Such a covering means inherently has a low heat capacity, and the magnitude of this heat capacity largely depends on the selection of the material of the covering means. The selection of the material and thickness of the covering means determines not only the mechanical strength but also other protective functions, such as insulation resistance, breakdown voltage, resistance to various media, etc. By using the coating means, the resistance to thermal conduction between the medium and the sensor element can be reduced to values approaching a mathematical minimum, and at the same time the heat capacity of the entire device is also minimized. Furthermore,
Such a coating means can be applied very economically to the temperature sensor, and the overall size of the device is also minimized as much as possible.

Other preferred embodiments of the present invention will be apparent from the description of the preferred embodiments of the present invention, which will be described below with reference to the following claims and the drawings.

EXAMPLE FIG. 1 shows 11 elements of a preferred embodiment of an immersion electronic thermometer intended for use with stationary or flowing media, especially water. This immersion electronic thermometer can be very widely and suitably applied to all stationary or flowing media in all fields, but due to its very compact structure, it can be used as an electronic thermostat in mixed water supply equipment. It is most suitable to use for. Particularly in such applications, the mechanical stress experienced by the immersion electronic thermometer is relatively small, and the chemical damage to the material is not significant.

The immersion electronic thermometer shown in FIG. 1 has a mounting base 1. A housing 2 attached to the mount 1 and inserted into the medium. and a temperature sensor 3 provided inside the housing 2.

The temperature sensor 3 in the housing 2 is electrically insulated from the medium, but is in contact with the medium via the housing 2 so as to transfer heat. As shown in a particularly preferred example in FIG. 2, the temperature sensor 3 has a sensor element 4 made of a semiconductor and an electrical connection line 5. With the mounting 1 and the O-ring 6 provided on the mounting 1 for sealing, the immersion thermometer becomes a socket in the wall of the medium tank, for example in the housing of a thermostat in a mixed water supply installation. It is inserted entirely and screwed down with an external screw. Other installation methods are readily conceivable, for example using an insertion device or an annular connecting flange, and so on.

An important point in the present invention is that the housing is connected to the sensor element 4.
and is placed directly on the connection wire 5, with only the terminals on both sides of the connection wire 5 exposed. Needless to say, the covering means 2 is made of an insulating material that has high thermal conductivity and is less susceptible to damage than the medium. The mechanical strength of this material should be comparable to that required for use with a particular immersion thermometer.

This coating technique is particularly clearly shown in FIG. 2, where the coating means 2 wrap the sensor cable f4 and the connecting wire 5 in a compact and separate manner. By this choice of material and thickness, the covering means 2 is adjusted to achieve the desired effect, for example a sufficiently large insulation strength (for example 500 volts for the thermostat considered here).

According to the teaching of the invention, first of all, the housing serves as a covering means which is arranged directly over the sensor element 4 and the connecting line 5 in such a way that the contact is the best possible. It is important to be present. This allows the heat capacity to be very low, the resistance to heat conduction between the medium and the sensor element 4 to be low, and the volume to be reduced to the desired volume.

How the covering element tu2 is applied to the sensor element 4 and the connecting line 5 will be explained in more detail below. Firstly, it is possible to encapsulate the sensor and the connecting wire in a glass capsule, as is done, for example, in the thermometer 1.

However, even if high-grade glass is used in this case, the mechanical strength is not sufficient for this application.

As a first possible improvement, therefore, it is conceivable to use a coating as a covering means, for example a plastic coating. Various well-known plastics, such as PTFE (trademark Terlon J
Polyamide (such as flon J) can be used as the coating material. Suitable implantation techniques are known in the art, which can be applied to small sensor elements and light-duty interconnections, and which can realize structures such as those described above.

It is particularly advantageous if the covering means 2 is in the form of a shrink tube which is shrink-molded over the sensor element 4 and the connecting line 5. As the shrink tube, for example, polytetrafluoroethylene, polyamide, silicone, polyolefin, etc. can be used. The choice of material depends on the field of application of the immersion thermometer, taking into account, in particular, the chemical nature of the medium and the temperature range.

Shrink-molding the covering means 2 in the form of a shrink tube is very advantageous in that the covering means 2 can be brought into close contact with the humidity sensor 3 and the resistance to heat conduction can be made as small as possible.

Similarly, the covering means 2 can be applied very simply to the temperature sensor 3.

That is, the temperature sensor 3
or push the sensor into the covering means 2,
After that, shrink molding is performed.

The sensor elements 4 currently in use have been made extremely small due to continuous improvements, and the weight ω of these connection lines 5 has also been kept very light. Even if a covering means 2, for example in the form of a shrink tube, is used, such a humidity sensor 3 is not very mechanically stable, and problems such as twisting occur especially when stretched over long distances. Therefore, it is desirable to provide a bracket 7 that matches the shape of the temperature sensor 3 covered on the mounting base 1. This bracket 7 is preferably made of insulating plastic with a small heat capacity, mechanically supports the temperature sensor 3, and is preferably half-open on the outside with respect to the covered sensor element 4 and connection wire 5. It has a compatible insertion groove 8. The shape of the bracket 7 should be such that it has as much mechanical stability as possible, and at the same time the heat capacity of the bracket 7 should be as small as possible so as not to reduce the performance of the entire measuring device.

As the material of the bracket 7, for example, a heptadyl copolymer (trademark: Hostafora+J) can be used.

When applied to a fluid medium, especially water, in a thermostat of a mixed water supply system, the temperature sensor 2 covered by the covering means 2 is formed into an elongated 0-shape, and both ends thereof are connected to the mounting base 1.
In particular, it is possible to attach the Correspondingly, in this specific example, the bracket 7 is shaped like an elongated rod, has insertion grooves 8 formed above and below, and is actually arranged between the connecting wires 5 of the temperature sensor 3. This is particularly shown in FIGS. 3 and 4. These figures also show that a retaining groove 9 for connection is provided at the tip of the bracket 7 shown here between the insertion grooves 8, and this is covered with the covering means 2 as shown in FIG. This shows that the connecting wire 5 is fitted. In this way, the temperature sensor 3 is attached to the bracket 7
is firmly fixed.

FIG. 3 further shows that the insertion groove 8 at the tip of the bracket 7 has been widened to receive the sensor element 4. As shown in FIG. (In other words, in the present preferred embodiment the sensor element 4 coated with the coating means 2 is arranged at the tip of the bracket 7. This is shown more clearly in FIG. 1. Such an arrangement In this case, the size of the sensor element 4 in the longitudinal direction is often too large to be attached to the tip of the bracket 7. In the embodiment shown here (FIG. 3), at the end of the bracket 7 that joins the mounting base 1, there are two openings 11 for passing the coated connecting wire 5. is the provision.

1 and 5 show another preferred embodiment of the immersion thermometer according to the invention, in which in the mount 1 both ends of the covering means 2 are arranged in seals 12, preferably two O-
It is characterized by being fixed with a ring. This is a particularly simple and effective configuration, which simplifies the hermetically sealed assembly of the temperature sensor 3 to the mounting base 1.

FIG. 1 further shows that in this specific example, the sensor element 3
Connector 1 for connecting the end of wire 5 to the outside
A sophisticated contact element 13 for making contact with the mounting base 1
This indicates that the The very compact construction of the immersion thermometer according to the invention allows the connecting wire 5 to be easily connected to the outside in the mounting base 1 by means of a sophisticated contact element 13, rather than being fixed with a conventional screw connector. It can be brought into contact with a connector 14 for connection.

In order to simplify the manufacture of the immersion thermometer according to the invention, it is desirable to construct it in several parts.

Particularly in constructing the invention, if the bracket 7 is inserted into the holder 15 and fixed by the contact means 16, and if the contact means 16 have a seal 12.1a, an ingenious contact element 13 and a connector 14. If so, the mount 1 includes an annular holder 15 and contact means 16 inserted into this holder. The contact means 16 in the holder 15 are likewise conveniently constructed, preferably of the same or similar insulating material as the bracket 7.

The holder 15 is made of a suitably shaped metal component, such as brass or aluminum, and has the necessary strength to be screwed, for example. The several parts arranged in the contact means 16 are preassembled and adjusted, so that the contact means 16 can be inserted directly into the holder 15.

In the preferred embodiment shown here, the contact means 16 are supported in the holder 15 by means of a spring ring 17. This makes assembly very simple and occupies only a small amount of space in this compact embodiment.

It goes without saying that it is also conceivable to use a screwed or simply pressed base. FIG. 5 shows the contact means 1 before receiving some parts which are additionally to be particularly arranged.
6 is shown in more detail.

FIG. 1 also shows that in the embodiment here the contact means 16 are sealed off from the holder 15 in a media-tight manner, and for this purpose preferably an annular seal 18, in particular an O-ring, connects the contact means 16 and the holder 15. It shows how it is placed between.

In the presently preferred embodiment, the holder 15 additionally has a partially inwardly projecting annular flange 19, opposite to which a bracket 7 is installed, in which the contact means 16 are introduced and held by a spring ring 17. When the bracket 7 is connected to the annular flange 19 by the contact means 16,
Pressed by It cannot be overlooked that this ensures that all parts of the immersion temperature 51 as a whole are firmly fixed to each other, and that the overall dimensions in question here are very small.

As explained in the prior art, various types of sensor elements for temperature sensor 3 are known. Particularly in a preferred field to which the immersion thermometer of the present invention is applied, it is convenient to use a semiconductor resistor, preferably a diode connected in conduction mode, as the sensor element 4, more specifically a silicon planar diode. . Such a sensor element 4. In particular, silicon Brainer diodes are extremely small and have properties that make them suitable for temperature measurement. If a diode is used as the sensor element 4, care must be taken to connect the connecting wire 5 with the correct polarity so that the diode is correctly in conduction mode for measurement purposes.

In the specific example shown in FIG. 1, the entire length of the immersion temperature 31 is only 30M1, the maximum outside diameter of the mounting base 1 part is 12m+, and the part of the temperature sensor 3 or bracket 7 is a little over 5s1. . The outer diameter of the covering means 2, which is a shrink tube, is a little over 2 mm before shrinkage and about 1.2 mm after shrinkage.
．． It is w. This means that the diameter of the connecting wire 5 is approximately 1.2a.
m, the sensor element 4 is fitted into a semicircular insertion groove 8 on the bracket 7, which has a diameter of about 1.8 fi.

In the figure, the black ring indicating the polarity of the conduction direction of the diode on the sensor element 4 indicates the cathode side of the diode.
Connection line 5 is negative wJt! 'I'. The positional relationship between some parts is clear from the corresponding color code of the connecting thread 14 and the asymmetry of the insertion path, and the position of the sensor element 4 can be uniquely reproduced, for example, even in a U-joint water supply system.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a preferred embodiment of the immersion electronic thermometer according to the present invention, FIG. 2 is a diagram showing a part of the covered temperature sensor of the immersion electronic thermometer of FIG. 1, and FIG. The figure is a vertical sectional view of the bracket for the unit shown in Figure 1, and Figure 4 is a vertical cross-sectional view of the bracket for the unit shown in Figure 1.
5 is a plan view of the bracket shown in the figure, and FIG. 5 is a sectional view of the contact means of the unit shown in FIG. 1, enlarged relatively from FIG. 1. DESCRIPTION OF SYMBOLS 1... Mounting base, 2... Covering means, 3... Temperature sensor υ, 4... Sensor element, 5... Connection wire, 7... Bracket, 8... Fitting groove ( insertion groove), 12... Seal, 13... Contact element, 14... Connection element, 15...
...Holder, 16...Connector (contact means), 18.
・Annular seal. Patent Applicant American Standard Incorporated

Claims (1)

[Claims] (1) A screw-type mounting base, a preferably tubular housing that is fitted into the mounting base and inserted into the medium to be measured, and a temperature sensor disposed in the housing. and a temperature sensor in the housing is electrically insulated from the medium to be measured and in contact with the medium to be measured through the housing to transfer heat, and the temperature sensor is preferably made of a semiconductor. An immersion electronic thermometer having a sensor element and an electrical connection line passing through the housing to the mount, the housing being arranged directly over the sensor element (4) and the connection line (5). Covering means (
2), wherein only the connecting end of the connecting wire is exposed, and is made of an electrical insulating material having good thermal conductivity, and is preferably mechanically strong and not easily damaged by the medium to be measured. immersion electronic thermometer for stationary or flowing medium to be measured, in particular water. (2) The immersion electronic thermometer according to claim 1, characterized in that said covering means comprises a thin layer structure, preferably a thin layer structure of plastic. (3) The immersion electronic thermometer according to claim 1, wherein the covering means is in the form of a shrink tube that is shrunk over the sensor element (4) and the connecting wire (5). (4) Said mounting base (1) has a bracket (7) for mechanical support of said temperature sensor (3), preferably made of electrically insulating plastic of low heat capacity, said bracket (7) preferably comprising: Claims 1 to 3 characterized in that the device has a fitting groove (8) half-opened on the outside for locating the sensor element (4) and the connecting wire (5) in the covering means (2). An immersion electronic thermometer according to any one of the following. (5) The temperature sensor (3) provided with the covering means (2) has an elongated U-shape, and the upper end of the U-shape is disposed in the mounting base (1). An immersion electronic thermometer according to any one of claims 1 to 4. (6) The covering means (2) is arranged at its free end in the mount (1) in a seal (12), preferably with two O-rings inserted into the seal (12). The immersion electronic thermometer according to any one of claims 1 to 5, characterized in that: (7) The contact element (13) in the mounting base (1) is provided to connect the connection wire (5) of the temperature sensor (3) and the connection terminal (14) to the outside. The immersion electronic thermometer according to any one of claims 1 to 6, characterized in that: (8) The mounting base (1) is preferably an annular holder (1).
5) and preferably a cylindrical contact member (16);
Preferably said bracket (7) is inserted into said holder (15) and fixed therein by said contact member (16), said contact member (16) comprising a seal (12), a contact element (13) and The immersion electronic thermometer according to any one of claims 1 to 7, characterized in that the thermometer houses at least one connecting terminal (14). (9) Said contact member (16) is sealed from said holder (15) against the intrusion of said medium to be measured; for this purpose preferably a circular seal (18), in particular an O-ring, is attached to said contact member (16). ) and the holder. (10) Immersion according to any one of claims 1 to 9, characterized in that the sensor element (4) is a semiconductor resistor, preferably a diode connected in conduction mode, preferably a planar silicon diode. Electronic thermometer.