DE202004013722U1 - Medical or clinical electronic thermometer has an additional heating resistance to preheat its ohmic resistance temperature sensor prior to use by a patient - Google Patents

Abstract

Medical thermometer comprises a digital thermometer (1) with a measurement sensor (2) that is placed on the skin and which has an ohmic resistance temperature sensor (3) whose resistance is proportional to the body temperature. A heating resistance (4) is incorporated in the measurement sensor to pre-heat it to a temperature value of approximately 36.6[deg] C.

Description

The Invention relates to a device for measuring body temperature according to the preamble of claim 1. Such devices mainly in the medical field for determining body temperature in humans used.

The Temperature of the human body, besides the core temperature, especially the surface temperature, is an important one Indicator for the state of health of each person.

devices for measuring body temperature are common distinguished into two types according to their operating principle. For one, the body temperature contactless e.g. measured with an infrared ray in the human ear. To the others come with devices for measuring body temperature in direct contact with the body surface, such as it e.g. in dealing with mercury thermometers and electronic Thermometers is the case.

at measuring body temperature The measured body temperature is measured using an infrared beam in the human ear frequently but by the conditions in the auditory canal, such as. the shape and texture the auditory canal, affected. This makes the temperature measurements too imprecise, so the body temperature received only as reference value and not as current temperature value can be. Therefore can Infrared thermometer not for exact measurements of body temperature be used in humans.

devices for measuring body temperature, that come into direct contact with the body surface are not subject to such influences and are therefore significantly more precise.

Become present for measuring body temperature frequently mercury thermometer still used. It refers to an expansion thermometer, in which this is encapsulated in a and vacuum-sighted sensors Mercury with glass capillary according to the present Temperature in the glass capillary expands and this expansion over a Tapped length scale becomes.

 On The disadvantage of these thermometers is the mercury used, in the event of destruction the glass capillary into the atmosphere can get and its fumes very harmful to health are. For this reason you are e.g. in hospitals and kindergartens future do not use mercury thermometers.

adversely is with these thermometers that because of the necessary heat transfer from the human skin to the mercury and the subsequent warming of the mercury the duration of a measurement with the temperature value of the skin is about 2-3 minutes too big.

For this reason, electronic thermometers have been used increasingly in recent years. So in DE 202 00 896 U 1 proposed an electronic thermometer, which have a metal sensor needle and in which an ohmic resistor is integrated, can measure the body temperature with high accuracy immediately after touching the human skin. However, the heat absorbed is further absorbed and distributed over the metal, so that the accuracy of the measured body temperature is gradually impaired. Measuring times of 1 to 2 minutes are therefore usually necessary to achieve a more precise average value. This means that the measurement time for electronic thermometers is also too long.

The The invention is therefore based on the object of a device for Measuring body temperature to develop in humans where the duration of the measurement process minimized and measured with high accuracy.

This Task is characterized by the characterizing features of claim 1 solved. Wiser design options result from the subclaims 2 to 3.

The new device eliminates the disadvantages of the prior art Technology. Advantageous when using the device according to the invention is that in the probe in addition to the temperature sensor, a heating resistor for preheating the probe integrated to a predetermined temperature value of close to 36.6 ° C is. This allows the sensor quickly from the ambient temperature in the range of the expected measuring temperature heated be so that the duration of the measurement process is crucial minimized.

Of The advantage here is that the electrical power of the heating resistor regulated by a temperature controller and thus optimally used becomes.

Advantageous is also that the predetermined temperature value on the temperature controller close to 36.6 ° C is adjustable. This ensures that after preheating of the sensor to the limit temperature actually only the body temperature is measured.

The invention is based on an embodiment tion example are explained in more detail. To show:

1 : the schematic structure of the thermometer according to the invention,

2 : a circuitry variant of the thermometer according to the invention.

As the 1 shows, the device consists of a rod-shaped thermometer 1 which has a sensor at one end 2 having. In the sensor 2 , which is a solid body made of a good heat-conducting material, are a temperature sensor 3 and an electrical heating resistor 4 integrated. The temperature sensor 3 and the electrical heating resistor 4 a connection to each other and an on / off switch 5 with the positive pole of a voltage source 6 coupled.

While the other connection of the temperature sensor 3 via a temperature display 7 with an actual value acquisition 8th of a temperature controller 9 is connected to the other connection of the electrical heating resistor 4 a control output 10 of the temperature controller 9 connected. Parallel to the heating resistor 4 is also a light emitting diode 11 connected.

The voltage supply of the temperature controller 9 takes place via a ground connection 12 of the temperature controller 9 with the negative pole of the voltage source 6 connected is.

How 2 shows is the main element of the temperature controller 9 a transistor 13 whose base is connected to a bridge 14 for the temperature display 7 whose collection with the heating resistor 4 and the light emitting diode 11 and their emitter with a first pre-resistance 15 are connected.

The bridge circuit 14 includes the temperature sensor in a first branch 3 and a second series resistor 16 , In the second branch of the bridge circuit 14 are a third series resistor 17 and an adjustable resistor 18 arranged. Both branches are indicated by the temperature display 7 separated from each other.

Instead of the in 2 However, other implementations are also possible.

The adjustable resistance is factory-set for correct adjustment of the device 18 , which takes over the function of a setpoint device, set so that when a temperature actual value of greater than or equal to 36.6 ° C is displayed on the temperature display 7 the transistor 13 locks and at the manipulated variable output 1U of the temperature controller 9 the negative pole of the voltage source 6 is not present. As a result, the circuits of the heating resistor 4 and the light emitting diode 11 not closed. The heating resistor 4 is therefore de-energized and cannot heat.

The light emitting diode 11 shows the operating state of the heating resistor 4 on. The heating resistor heats 4 , the LED lights up 11 , Is the heating resistor 4 on the other hand without current, then the LED lights up 11 Not.

If the body temperature is to be measured, the thermometer is used on the one hand 1 via on / off switch 5 switched on and, as is known, the sensor 2 brought into contact with a suitable skin surface of a human. Now is the one with the temperature sensor 3 measured and with the temperature display 7 The actual temperature value registered below the temperature setpoint of 36.6 ° C is due to the transistor 13 a colector-emitter current in front and the circuit of the heating resistor 4 and the circuit of the light emitting diode 11 is closed. This heats the heating resistor 4 and the LED lights up 11 ,

Now the heating resistor heats up 4 the sensor 2 until a temperature of 36.6 ° C is reached. If an actual temperature value of greater than or equal to 36.6 ° C is registered, the transistor blocks 13 and no more collector-emitter current flows. At the same time, the LED goes off 11 off and the heating resistor 4 no longer heats.

If the measured actual temperature value continues to rise until a steady state is reached, then this corresponds to that with the temperature sensor 3 measured and with the temperature display 7 displayed actual temperature value of the body temperature of the person. This steady state is reached after a few seconds.

1

 thermometer

2

 probe

3

 temperature sensor

4

 heating resistor

5

 On / off switch

6

 voltage source

7

 temperature display

8th

 Actual value

9

 thermostat

10

Manipulated value output

11

led

 12

 ground connection

13

transistor

14

bridge circuit

15

first dropping resistor

16

 second dropping resistor

17

 third dropping resistor

18

 adjustable resistance

Claims (3)

contraption 7 , for measuring body temperature, consisting of an electronic thermometer ( 1 ), in a sensor placed on the skin ( 2 ) a temperature sensor ( 3 ) is integrated in the form of an ohmic resistance and the measured resistance value of which is a measure of the body temperature, characterized in that in the measuring sensor ( 2 ) additionally a heating resistor ( 4 ) for preheating the sensor ( 2 ) is integrated to a predetermined temperature value of close to 36.6 ° C. Device according to claim 1 , characterized in that the heating resistor ( 4 ) on a temperature controller ( 9 ) connected. Device according to claim 2 , characterized in that the temperature controller ( 9 ) the predetermined temperature value of close to 36.6 ° C is adjustable.