Abstract
A device (1) for determining the concentration of a gas component is configured with a radiation source (30) for emitting (31) a light radiation or heat radiation in an infrared wavelength range. A detector array (40) has at least two detector elements (50, 60), configured to detect the radiation generated by the radiation source (30), in an angular arrangement (52, 62) and with filter elements (51, 61). At least one of the two detector elements (50, 60) is oriented in an angular arrangement (52, 62) in relation to a vertical axis (32), so that a range of overlap (65) is obtained due to the angular arrangements (52, 62). The range of overlap (65) causes attenuations in the propagation of light, which attenuations may be due, for example, to gas molecules or moisture (400), affect both detector elements (50, 60) and are thus compensated concerning the concentration determination.
Claims
1. A device for determining a concentration of a gas component in an inhaled gas or in an exhaled gas of a living being, the device comprising: a radiation source configured to emit light or heat radiation in a radiation direction in a wavelength range of lambdal (1)=2.5 m to lambda2 (2)=14.0 m, wherein the radiation source is configured as: a flat radiator, as a diaphragm radiator or as a radiation element and is configured with an essentially planarly configured radiating surface; or a light-emitting diode (LED) configured with an essentially planarly configured radiating surface; and the radiating surface is configured for mainly uniform radiation over the radiating surface; a detector array with at least two detector elements configured to detect the radiation generated by the radiation source; at least two bandpass filter elements each of the filter elements being arranged at one of the at least two detector elements; at least one optically reflecting element having a flat configuration and arranged opposite the radiation source; and a control unit configured to control operation of the radiation source and to detect the signal of the at least two detector elements, wherein: at least one of the at least two bandpass filter elements is configured to be optically transparent for infrared radiation which is absorbed by a measured gas; at least one of the at least two bandpass filter elements is configured to be optically transparent for a radiation that is not absorbed by the measured gas; at least one of the two detector elements with at least one of the bandpass filter elements is arranged in an angular arrangement at an angle in a range of 20 to 80 in relation to an axis extending through the radiation source parallel to or identical to the radiation direction of the emission of the radiation source; the radiating surface is perpendicular to the axis; the radiating surface comprises an area in a range of 2.0 mm.sup.2 to 10 mm.sup.2; each of the at least two detector elements is arranged at a first distance from the axis in a range of 0.1 mm to 10.0 mm; each of the at least two bandpass filter elements is arranged at a second distance from the axis in a range of 0.1 mm to 10.0 mm; the detector array is arranged on a same side, with respect to the oppositely arranged reflecting element, as the radiation source and is arranged adjacent to the radiation source; the at least two detector elements are arranged at a reflecting element distance from the reflecting element in a range of 0.1 mm to 5.0 mm; and the reflecting element distance is a distance directly in a range of or along the axis extending from the reflecting element between the at least two detector elements.
2. A device in accordance with claim 1, wherein: the detector array is arranged opposite the radiation source at a detector array to source distance in a range of 0.1 mm to 10.0 mm; the detector array to source distance is obtained as a distance directly in a range of or along the axis extending between the two detector elements; the radiation source is arranged centrally on the axis extending between the two detector elements.
3. A device in accordance claim 1, wherein the bandpass filter elements are configured to optical filter infrared light in a transmission range of a wavelength range of 2.5 m to 14 m.
4. A device in accordance with claim 1, wherein the detector elements are configured as pyrodetectors, bolometers, semiconductor detectors, thermopiles or thermocouples.
5. A device in accordance with claim 1, wherein: at least two other of the at least two detector elements, with at least one of the bandpass filter elements, is arranged in an angular arrangement at an angle in a range of 20 to 80 in relation to the axis extending through the radiation source parallel to or identical to radiation direction of the emission of the radiation source to provide the detector array with more than two angular arrangements with detector elements and with bandpass filter elements in a spatial arrangement in the form of lateral surfaces of a rectangular or square truncated pyramid around a center.
6. A device in accordance with claim 1, wherein the detector array forms, together with the radiation source, a flow guide element configured to guide inhaled gas and/or exhaled gas, so that the measured gas flows through the flow guide element as a main stream and the gas concentration can be detected in the main stream.
7. A device in accordance with claim 1, wherein: the detector array is configured together with the radiation source as a component of a flow guide element; the flow guide element is configured to guide inhaled gas and/or exhaled gas such that the measured gas used for the concentration measurement is the measured gas that is representative of quantities of gas that flows through the component essentially in a center of the flow guide element as a side stream as a part of a main stream; and a concentration measurement in the measured gas is detectable in the side stream.
8. A device in accordance with claim 1, wherein the detector array together with the radiation source is configured as a component arranged laterally in a flow guide element; the flow guide element is configured for guiding inhaled gas and/or exhaled gas such that the measured gas used for the concentration measurement is measured gas that is representative of quantities of gas that flows through the component essentially in a lateral edge area of the flow guide element in a side stream as part of a main stream; and a concentration measurement in the measured gas is detectable in the side stream.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) In the drawings:
(2) FIG. 1a is a first schematic view of a device for concentration determination;
(3) FIG. 1b is another, second schematic view of a device for concentration determination;
(4) FIG. 1c is a schematic view of a variant of a device for concentration determination according to FIG. 1a or 1b;
(5) FIG. 2 is an arrangement of a device for concentration determination at a flow guide element;
(6) FIG. 3 is another arrangement of a device for concentration determination at a flow guide element; and
(7) FIG. 4 is a flow guide element a device for concentration determination.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
(8) Referring to the drawings, FIG. 1a shows a first schematic view of a device 1 for determining the concentration of at least one gas component in a breathing gas mixture. The device 1 shown has a radiation source 30 with a radiation element 300. A detector element 50 and a detector element 60 are arranged opposite the radiation source 30 at a vertical distance l.sub.3 33. Bandpass filter elements 51, 61 are arranged at the detector elements 50, 60. The bandpass filter elements 51, 61 are preferably configured as bypass filter elements that are transparent to a predefined wavelength range of the radiation 31 emitted by the radiation source 30. This FIG. 1a shows a coordinate system with vertical reference axis 32 and with a horizontal reference axis 36, to which system reference is made in the description of the positions of the components in relation to one another. Thus, a radiation takes place from the radiation source 30 out of a horizontal plane of radiation 37, the horizontal plane 37 being parallel to the horizontal reference plane 36.
(9) A control unit 9 is provided, which is connected to the radiation element 300 by means of control lines 93, 93. Furthermore, the control unit 9 is connected to the detector element 60 by means of control lines 96, 96. The control unit 9 is furthermore connected to the detector element 50 by means of control lines 95, 95. The detector element 50 together with the corresponding filter element 51 forms an angular arrangement 52. The detector element 60 together with the corresponding filter element 61 forms an angular arrangement 62. The angular arrangements 52 and 62 together form a detector array 40, which functionally forms the device 1 for determining the concentration of a gas component in conjunction with the radiation source 30 and the control unit 9. The arrangement of the detector array 40 in relation to the vertical axis 32 and to the horizontal reference axis 36 is determined by distances and angles of the angular arrangements 52, 62.
(10) The angular arrangement 52 is configured in this FIG. 1a in a parallel arrangement in relation to the horizontal reference axis 36 as well as to the horizontal plane of the radiation 37. An angle .sub.1 53 of the angular arrangement 52 to the vertical reference axis 32 equaling 90 is thus obtained. A horizontal distance l.sub.1 34 of the detector elements 50 to the central axis 32 is obtained in the detector array 40. A distance l.sub.1 34 to the central axis 32 is obtained in the detector array 40 for the detector element 60. A distance l.sub.2 35 of the bandpass filter element 51 to the central axis 32 is obtained in the detector array 40. Furthermore, a distance l.sub.2 35 is obtained for the filter element 61 to the central axis 32 in the detector array 40. Due to the arrangement of the angular arrangement 52 at an angle of 90 to the central axis 32, the distances l.sub.1 34 and l.sub.2 35 to the central axis are identical for the detector element 50 and the filter element 51.
(11) The angular arrangement 62 is configured sloped to the central axis 32 at an angle of .sub.2 63. The angle .sub.2 63 is defined here in an angle range markedly lower than 90 to the central axis 32. Due to the slope of the angular arrangement 62 with the detector element 60 and with the filter element 61 at an angle .sub.2 63, a range of overlap 65 is obtained in the radiation 31 for the radiation 31 emitted by the radiation source 30 along the vertical distance l.sub.3 33 between the radiation source 30 and the detector array 40. This range of overlap 65 is obtained vertically from the plane of the angular arrangement 62 in the direction of the radiation source 30. Due to the angles .sub.1 53 and .sub.2 63, the situation arises, for example, for gas molecules or condensate (moisture, such as water vapor or water droplets) 400, which are shown in this FIG. 1a as an example on the central axis 32 in the vicinity of the radiation source 30, that the radiation 31 of the radiation source passes through this gas molecule 400 and it becomes effective as radiation 31 to both the detector element 50 and the detector element 60. It is thus ensured that, for example, moisture (condensate) 400 attenuates the radiation to the detector element 50 as well as to the detector element 60 in the same manner. This leads to the possibility of eliminating the effect of moisture from the formation of the ratio of the signals of the detector element 50 and of the detector element 60. The range of the overlap can be defined by selecting the angles .sub.1 53 and .sub.2 63 in relation to one another as well as to the vertical central axis 32. The extension of the range of overlap 65 is still defined in conjunction with the selection of the vertical distance l.sub.3 33 between the radiation source 30 and the detector array 40.
(12) The control unit 9 analyzes the signals of the detector elements 50, 60 by means of suitable electronic components 11 (amplifiers, analog-to-digital converters, microcontroller) and provides an output signal. The output signal 99 is representative here of the signals detected by the detector elements 50, 60 as well as of the ratio of the detected signals and hence it is also representative of a gas concentration derived from these signals or from the signal ratio.
(13) FIG. 1b shows another, second schematic view of a device 1 for determining the concentration of at least one gas component in a breathing gas mixture. Components that are identical in FIG. 1a and FIG. 1b are designated by the same reference numbers in this FIG. 1b as the correspondingly equivalent elements in FIG. 1a.
(14) With the other, second schematic view, FIG. 1b shows a modified variant of FIG. 1a. Unlike in FIG. 1a, the radiation source 30 is arranged in FIG. 1b on the same side as the optical elements and the detectors. The device 1 shown has a radiation source 30 with a radiation element 300. A detector element 50 and another detector element 60 are arranged directly adjacent to the radiation source 30. Bandpass filter elements 51, 61 are arranged at the detector elements 50, 60. A reflector 39, for example, a plane mirror, is arranged as a reflecting optical device opposite the radiation source 30. The reflector 39 acts as a mirror for the radiation 31 emitted by the radiation source 30 and brings about a reflection of a reflected radiation 31 towards the bandpass filter elements 51, 61 as well as to the detector elements 50, 60. The bandpass filter elements 51, 61 transmit light in a predefined wavelength range. A coordinate system with vertical reference axes 32 and horizontal reference axes 36 is shown in this FIG. 1b. These axes are used, in a similar manner as in the description of FIG. 1a, as a reference for the position of the components in relation to one another and in space. A control unit 9 is provided, which is connected to the radiation element 300 of the radiation source 30. The arrangement by means of control line 93, 93 and 96, 96 as well as 95, 95 for connecting the control unit 9 to the detector elements 60, 50 corresponds to the arrangement according to FIG. 1a and to the corresponding description, to which reference shall be made here. The detector element 50 forms, together with the corresponding filter element 51, an angular arrangement 52. The detector element 60 likewise forms an angular arrangement 62 with the corresponding filter element 61. These angular arrangements 52, 62 form, together with the radiation source 30, a detector array 41, which functionally forms the device 1 for determining the concentration of a gas component in conjunction with the control unit 9 and the reflector 39. The arrangement of the detector array 41 in relation to the axes 32, 36 is defined by distances and angles of the angular arrangement 52, 62. A horizontal distance l.sub.1 34 of the detector element 50 from the central axis 32 is obtained in the detector array 41. A distance l.sub.1 34 from the central axis 32 is obtained in the detector array 41 for the detector element 32. A distance l.sub.2 35 of the bandpass filter element 51 from the central axis 32 is obtained in the detector array 41. Furthermore, a distance l.sub.2 35 from the central axis 32 is obtained in the detector array 41.
(15) The angular arrangements 52, 62 are always sloped to the central axis 32 at angles .sub.1 53 and .sub.2 63 in this FIG. 1b.
(16) The angles .sub.1 53 and .sub.2 63 have an angle range markedly smaller than 90 relative to the central axis 32. The angles .sub.2 63 and .sub.1 53 have, for example, different angular dimensions in this FIG. 1b, but the idea of the present invention also covers the case in which .sub.2 63 and .sub.1 53 can also have identical angular dimensions to the central axis 32. Due to the slope of the angular arrangement 52 with the detector element 50 and with the filter element 51 at the angle .sub.1 53 and due to the slope of the angular management 62 with the detector element 60 and with the filter element 61 at the angle .sub.2 63, ranges of overlap in a reflected radiation 31 are obtained for the radiation 31 emitted by the radiation source 30 along the vertical distance between the radiation source 30 and the detector array 41 after reflection by means of the reflector 39. The angular arrangements 52, 62 are configured in reference to the horizontal reference axis 36, the central axis 32 and a horizontal plane of the light reflection 37, which is arranged parallel to the horizontal reference axis 36. The range of overlap, which is obtained on the basis of the angular arrangements 52 and 62, causes impurities or condensate, which are present, for example, in the vicinity of the reflector 39 in the reflected radiation 31, to influence, i.e., possibly attenuate, the detector element 50 in the same manner as the detector element 60. This leads to the possibility, as described in connection with FIG. 1a, of eliminating the influence of moisture 400 (FIG. 1a) or impurities from the ratio of the signals of the detector element 50 and of the element 60. The range of overlap can be defined by selecting the angles .sub.1 53 and .sub.2 63 in relation to one another as well as to the vertical central axis 32. Unlike in FIG. 1a, a longer, in the simplest case twice as long a beam path is obtained in this FIG. 1b for the path of the radiation 31 towards the reflector 39 and to the reflected path of the reflected radiation 31 to the detector elements 50, 60. The consequence of this is that the light beams reaching the detector elements 50, 60 are of a lower intensity than in FIG. 1a. This causes a difference concerning the sensitivity of the device 1 for determining the concentration of a gas component in this FIG. 1b. The analysis of the signals of the detector elements 50, 60 in the control unit 9 is carried out in the same manner as described in connection with FIG. 1a, by means of suitable electronic components 11. The control unit provides an output signal 99, which is representative of the signals of the detector elements 50, 60 or of the ratio of the signals of the detector elements 50, 60. The output signal 99 thus provides a gas concentration derived from the signals on the basis of the detected signals of the detector elements 50, 60 for further processing, for example, for a display unit 94 (FIG. 2).
(17) FIG. 1c shows a schematic view of a variant of a device for determining the concentration according to FIG. 1a or 1b. Identical components in FIGS. 1a, 1b and FIG. 1c are designated in this FIG. 1c by the same reference numbers as the correspondingly equivalent components in FIGS. 1a and 1b.
(18) FIG. 1c shows a variant according to FIG. 1a or FIG. 1b. FIGS. 1a and 1b show two basic variants of the configuration of detector elements 50, 60, radiation source 30 in conjunction with or without a reflector 37. FIG. 1c shall show a variant in which not only two detector elements 50, 60 are arranged as a device for gas measurement, but a total of more than two detector elements are arranged in a circular or rectangular configuration in relation to one another. Such a configuration with a plurality of detector elements makes it possible to make a measurement with a plurality of measured signals, for example, of three or more gases, with three or more detector elements associated with the measured gases in relation to a reference by means of a reference detector element. A funnel, which has the shape of an inverted truncated pyramid with a rectangular or square base or frustum surface, is shown as the geometric configuration in this FIG. 1c.
(19) FIG. 1c is configured for this as follows:
(20) A total of four angular arrangements 52, 62, 72, 72 are configured structurally around a center 2 in an arrangement sloped towards a central axis 32 at angles .sub.1 52, .sub.2 62, .sub.3 73, .sub.3 73. The horizontal axes 36 as well as 36 and the vertical axes 32 are always shown in FIG. 1c arranged at the angular arrangements 52, 62, 72, 72 in order to make it possible to clearly show the spatial arrangement in this FIG. 1c. The axes 32, 32, 36, 36 illustrate here the same spatial coordinate system as is shown in FIGS. 1a and 1b.
(21) In a configuration of FIG. 1c according to FIG. 1b with the device 1 for determining the concentration of a gas component, a radiation source 30, indicated by broken lines, is arranged centrally between the angular arrangements 52, 62, 72, 72. Not shown in this FIG. 1c, a reflector element is again necessary opposite this radiation source 30. Such a configuration is obtained, as can be seen in FIG. 1b, with an arrangement of a reflector 39 (FIG. 1b) at a wall located opposite the radiation source 30 with a horizontal plane of the light reflection 37 (FIG. 1b). The radiation source 30 is shown here directly at the center 2 with a radiation element 300, indicated here by a coil drawn by broken lines.
(22) The radiation source 30 at the center 2 is omitted in a configuration of FIG. 1c with a device 1 for determining the concentration of a gas component according to FIG. 1a. The radiation source would be arranged in such a configuration opposite the angular arrangements 52, 62, 72, 72, and the area around the center 2 would be free of measuring or optical components (52, 62, 72, 72). As an alternative to this, a configuration may be selected, in which this area around the center 2 does not remain free. A configuration can then be selected as a variation in which another angular arrangement is made possible there. This additional angular arrangement is not shown specifically in this FIG. 1c, but it comprises all the features with a detector element and with a filter element and is arranged planarly to the horizontal plane 36 or 36 as a reference detector element. Such an additional angular arrangement may be used, for example, to provide a reference signal. The variant is now obtained in which four rather than the three different gases can be detected with the angular arrangements 52, 62, 72, 72 in reference to the one reference detector element, which is arranged centrally between the other four detector elements. A compensation of interferences due to the common range of overlap 65 (FIG. 1a) of the reference detector element with all four angular arrangements 52, 62, 72, 72, which is not shown in this FIG. 1c for the sake of clarity, is thus achieved by means of the reference detector element.
(23) This advantageously leads to an embodiment in which interferences, impurities, condensate and other impurities present in the radiation are equally reflected in all three measured signals and in the reference signal, so that an optimal compensation of these effects is ensured.
(24) FIGS. 2, 3, 4 show arrangements of a device for determining the concentration according to FIGS. 1a, 1b, 1c at a flow guide element. FIGS. 2, 3, 4 shall be described in a joint description of the figures concerning the features shared in common with one another, but also in respect to the differences from one another.
(25) Identical components in FIGS. 2, 3, 4 and in FIGS. 1a, 1b, 1c are designated by the same reference numbers as the correspondingly equivalent components in FIGS. 2, 3, 4 as well as in FIGS. 1a, 1b, 1c.
(26) FIG. 2 shows a device 1 for determining the concentration of a gas component (FIG. 1b) in a flow guide element 100. The flow guide element 100 is configured to feed a flow with a quantity of gas 80 for a measurement by means of the device 1 (FIG. 1b). Angular arrangements 52, 62 are shown in conjunction with a radiation source, with a radiation element and with a control unit 9. The angular arrangements 52, 62 with the radiation source and with the control unit 9 are arranged in a holding element 97, which is coupled with the flow guide element 100 by means of sealing elements 98. The mode of operation of the arrangement according to FIG. 2 is as described in connection with FIG. 1b.
(27) FIG. 4 shows an arrangement comparable to that in FIG. 2 in a flow channel 100 with a device 1 for determining the concentration of a gas component. A holding element 97, which is inserted into the flow guide element 100 by means of sealing elements, is present here as well. Unlike in FIG. 2, only a partial quantity in the form of a side stream of the quantity of gas flowing in the flow guide element 100 enters the device 1 (FIG. 1b) for determining the concentration of a gas component in the flow guide element 100 in this FIG. 4. This FIG. 4 thus shows a measurement in a so-called bypass. Just as in FIG. 2, a reflector 39, this time shown in an arched configuration, is arranged opposite the radiation source 30 in this FIG. 4 as a part of the holding element 97.
(28) The device 1 (FIG. 1b) for determining the concentration of a gas component in a side stream is arranged in this FIG. 4 in the bypass with the arrangement of the holding element 97 as an insert in the flow guide element 100, configured in the form of a T-piece, is arranged and acts for the purpose of measurement nearly in the flow center of the flow guide element 100, i.e., essentially in the center of the flow guide element 100. As an alternative and in addition, an arrangement of the holding element 97, in which the device 1 (FIG. 1b) for determining the concentration of a gas component is not arranged and acts for the purpose of measurement in the center of the flow, but in the marginal area of the flow guide element 100, is shown this FIG. 4. A configuration of the bypass in the area of an edge flow in the marginal area of the flow guide element 100 is thus obtained.
(29) Unlike FIG. 2 as well as FIG. 4, FIG. 3 shows a device 1 for determining the concentration of a gas component according to FIG. 1a in a flow channel 100. The radiation source 30 is arranged opposite two angular arrangements 52, 62 at a flow guide element 100. The angular arrangements 52, 62 and of the radiation source 30 are arranged opposite at a point of the flow guide element 100 at which the flow cross section is reduced in the form of a Venturi tube. It is necessary in this configuration according to FIG. 3 to provide elements of a control unit 9 from two sides. This makes it possible both to operate the angular arrangements 52, 62 with the detector elements 50, 60 (FIG. 1a) and to amplify the signals. In addition, the control unit 9 is used to actuate the radiation source 30 and to send an output signal 99.
(30) An output signal 99, which is, as was explained above in FIGS. 1a and 1b, representative of a detected gas concentration, is provided in FIGS. 2, 3, 4.
(31) Unlike FIG. 4, FIG. 3 as well as FIG. 2 are configured such that the measurement of the gas concentration of the quantity of gas 80 is not carried out in a bypass stream, but directly in the main stream. FIG. 2 shows a medical device 200 as well as a display unit 94 by broken lines as respective optional components. These optional components represent exemplary possibilities of sending the output signal 99 for further processing and use.
(32) These optional components 200, 94 are not shown in FIGS. 3 and 4, but they shall likewise be considered to be included in the configurations according to these FIGS. 3 and 4.
(33) While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
APPENDIX
List of Reference Designations
(34) 1, 1 Device for determining the concentration of a gas component 2 Center (intersection of the axes 32 and 36) 9 Control unit 11 Electronic components 30 Radiation source 31 Radiation 31 Reflected radiation 32, 32 Vertical (length) axis, central axis, vertical reference axis 33 l.sub.3, l.sub.3 vertical distance 34 l.sub.1 distance of the detector element 50 from the central axis 32 34 l.sub.1 distance of the detector element 60 from the central axis 32 35 l.sub.2 distance of the filter element 51 from the central axis 32 35 l.sub.2 distance of the filter element 61 from the central axis 32 36, 36 Horizontal reference axis 37 Horizontal (width) plane of radiation 37 Horizontal (width) plane of light reflection 38 Wall 39, 39 Reflector, mirror element 40 Detector array 41 Detector array, reflective 50 Detector element 51 Bandpass filter element 52 Angular arrangement 53 Angle .sub.1 60 Detector element 61 Bandpass filter element 62 Angular arrangement 63 Angle .sub.2 65 Range of overlap 72 Angular arrangement 72 Angular arrangement 73 Angle .sub.3 73 Angle .sub.3 80 Quantity of gas, gas concentration 93, 93 Control line to the radiation element 300 94 Display unit 95, 95 Data line, signal line 96, 96 Data line, signal line 97 Holding element 98 Insert, sealing element 99 Output signal 100, 100, 100 Flow guide element 200 Medical device, ventilator, anesthesia device 300 Radiation element (diaphragm, coil) 400 Gas molecule, condensate
