Heated sensor arrangement

Abstract

The present invention relates to a heated sensor arrangement (1) for use with an evaporator tube (1000, 100A) of an evaporator (1001) of a refrigerant circuit. The heated sensor arrangement (1) comprises a cylindrical first housing portion (10) extending along a first longitudinal axis (X) and having a lateral first outer surface (11), a heating element (100) arranged inside the first housing portion (10), a temperature sensor (201) arranged inside the first housing portion (10); and a tubular second housing portion (20) having a lateral second outer surface (21). Further, the sensor arrangement (1) is configured for insertion of the first housing portion (10) into the second housing portion (20) such that the second housing portion (20) at least partially covers the first outer surface (11) of the first housing portion (10). In order to provide a heated sensor arrangement which allows information about a share of liquid in a flow of refrigerant to be obtained with improved accuracy, the second outer surface (21) of the second housing portion (20) comprises a supporting section (25) extending along a portion of the second outer surface (21) and configured to contact the evaporator tube (100). In addition, the temperature sensor (201) is arranged offset along the first longitudinal axis (X) relative to the supporting section (25).

Description

[0001] Heated sensor arrangement

[0002] The present invention relates to a heated sensor arrangement for use with an evaporator tube of an evaporator of a refrigerant circuit. Further, the present invention relates to an arrangement for detecting a share of liquid in a flow of refrigerant, which comprises a heated sensor arrangement.

[0003] In general, the use of evaporators as part of a temperature control system for example used to control the temperature in buildings is known. In this regard, a refrigerant is typically circulated inside a refrigerant circuit for example using a pump. While circulating refrigerant inside the refrigerant circuit of the temperature control system, a share of liquid in the refrigerant flow is naturally changed in an evaporator. In other words, in an evaporator the refrigerant typically goes from a state comprising a lower vapor quality and thus a high level of liquid to a state comprising a higher vapor quality and thus a low level of liquid. Hence, a mass fraction of liquid and vapor, i.e. gas, is for example different at an evaporator inlet compared to an evaporator outlet.

[0004] In order to operate the temperature control system in an energy-efficient manner and to be able to use a smaller amount of refrigerant, i.e. a smaller charge of refrigerant, in the system, e.g. a smaller charge of ammonia, which is toxic and thus harmful to the environment and health, it is also known to use sensors that allow, for example, the refrigerant flow rate flowing through the evaporator tubes of the evaporator to be regulated to an optimum and thus reduce the risk in the case of leakage. In this regard, it is for example known to use a heated sensor arrangement to determine a mass fraction of liquid and vapor, i.e. a gas / liquid mixture, flowing in the refrigerant circuit.

[0005] On this basis and in order to ensure the best possible control of the temperature control system, it is necessary to measure the share of liquid in the flow of refrigerant as accurately as possible, with a minimum deviation from the actual mass fraction of liquid and vapor flowing through the refrigerant circuit. In addition, and in order to enable an evaporator tube of an already installed evaporator to be easily retrofitted with a heated temperature sensor arrangement, the heated temperature sensor arrangement must also be optimized in this respect.

[0006] It is therefore an object of the present invention to provide a heated sensor arrangement which allows information about a share of liquid in a flow of refrigerant to be obtained with improved accuracy. Further, it is an object of the present invention to provide a heated sensor arrangement which is configured to be easily retrofitted to an evaporator tube.

[0007] The object of the present invention is solved by a heated sensor arrangement according to claim 1 and an arrangement according to claim 15.

[0008] The heated sensor arrangement for use with an evaporator tube of an evaporator of a refrigerant circuit comprises at least a cylindrical first housing portion, a heating element, a temperature sensor and a tubular second housing portion. In other words, the heated sensor arrangement is configured to be used with an evaporator tube of an evaporator of a refrigerant circuit.

[0009] The refrigerant circuit may for example comprise in addition to the evaporator configured to evaporate the refrigerant further components such as for example a compressor configured to compress the refrigerant, a condenser configured to condense the compressed refrigerant and an accumulator or receiver. The heated sensor arrangement may be used with an evaporator tube arranged inside the evaporator or conducting refrigerant to or from the evaporator. In other words, the evaporator tube may be arranged inside an evaporator housing or may be a part of an evaporator inlet tube or an evaporator outlet tube. In order to maximize benefits from the heated sensor arrangement, the evaporator tube should in principle be enabled to transfer both vapor and liquid, depending for example on an operating mode, for example depending on a circulating rate of a pump, which may for example be optimized by use of the heated sensor arrangement.

[0010] The heated sensor arrangement may for example be used with a bottom-feed, top-feed or side-feed evaporator. However, the heated sensor arrangement may also be used with different evaporators or even with different devices used for conducting vapor and liquid. If the heated temperature sensor is used with an evaporator, the refrigerant used in the refrigerant circuit, to which the evaporator belongs, may for example be ammonia. The temperature of the refrigerant may for example be about -20 °C, i.e. 253.15 K. The evaporator tube may for example be a stainless-steel pipe, a carbons-steel pipe, a copper pipe or an aluminum pipe configured to conduct vapor, liquid or a vapor / liquid mixture. However, when using ammonia as a refrigerant, the evaporator tube must not be made of copper. As the heated sensor arrangement may also be used with refrigerants other than ammonia, the use of copper material for the evaporator tubes may be an option for refrigerant circuits utilizing other refrigerants. The evaporator tube may preferably comprise a very thin wall thickness in a range of for example between 0.5 mm and 2.5 mm.

[0011] In one aspect, the evaporator tube may have an outer diameter of less than 30 mm, for example an outer diameter between 10 mm and 27 mm. In one aspect, the refrigerant circuit may be a pump circulated system which may be a controlled circulating rate system (CCR-system) or a wet direct expansion system (WDX- system). The heated sensor arrangement may for example be used on a most loaded evaporator tube of a CCR-system or on a least loaded evaporator tube of a WDX-system.

[0012] According to the invention, the cylindrical first housing portion of the heated sensor arrangement extends along a first longitudinal axis and has a lateral first outer surface. In the following, the term "lateral" with respect to an outer surface may be understood as an outer circumferential surface excluding end faces. The first longitudinal axis may be a first longitudinal central axis. The first longitudinal axis may also be an axis of symmetry with respect to which the cylindrical first housing portion is rotationally symmetrical. In this regard, the first housing portion may for example be a hollow cylinder comprising a respective lateral first outer surface and two end faces. According to one aspect, one end face may be closed so that an interior of the first housing portion may only be accessible during manufacturing and assembly of the components of the heated sensor arrangement from one side. However, once the heated sensor arrangement is fully assembled and ready for installation to an evaporator tube, the first housing portion may no longer be accessible.

[0013] The heating element of the heated sensor arrangement is arranged inside the first housing portion. In other words, the heating element may be arranged in an interior of the first housing portion and may be configured to heat the first housing portion. As aforementioned, the interior may be accessible from a first end face and a second end face or only from one of the two end faces. Hence, if the first housing portion is closed on one side, i.e. when one end face is a closed end face, according to one aspect the heating element may rest or abut against this closed end face of the first housing portion. Further, if one end face of the first housing portion is permanently closed, for example not closed by a cap, the heating element may be inserted into the first housing portion first, i.e. for example before the temperature sensor, for example during assembly of the heated sensor arrangement.

[0014] In one aspect, the heating element may comprise an outer diameter, i.e. a heating element diameter, which is at least substantially the same as an inner diameter of the interior of the first housing portion. In this regard, the heating element may be in direct contact with a lateral first inner surface of the first housing portion. Preferably, at least a portion of the heating element contacts the lateral first inner surface completely in the circumferential direction. In other words, there is preferably a part or portion of the lateral first inner surface against which the heating element completely abuts in the circumferential direction.

[0015] The heating element may be an electrical heating element, e.g. an ohmic heating element, which may for example be powered by an external power source. Corresponding electric leads used to power the heating element may run partially inside the first housing portion. In this regard, electric leads may for example be guided through an insert, which may be arranged inside the first housing portion.

[0016] Further, the temperature sensor is arranged inside the first housing portion. In other words, the temperature sensor may be arranged in the interior of the first housing portion and may be configured to detect a temperature of the first housing portion. In this regard, the temperature sensor may be thermally coupled to the first housing portion. The temperature sensor may be configured to provide an electrical signal indicative of a temperature or a temperature change. In one aspect, the temperature sensor may for example be a thermocouple or resistance temperature detector (RTD) such as for example a PtIOOO element.

[0017] Furthermore, the heated sensor arrangement comprises the tubular second housing portion having a lateral second outer surface. In one aspect, the second housing portion may be a cylindrical second housing portion, for example a hollow- cylindrical second housing portion. Further, the tubular second housing portion may comprise a second longitudinal axis. The second longitudinal axis may be a second longitudinal central axis. The second longitudinal axis may be in line or may coincide with the first longitudinal axis. In other words, if the first housing portion is rotationally symmetric with respect to the first longitudinal axis, the first housing portion may also be rotationally symmetric with respect to the second longitudinal axis. The second housing portion may be provided to a user separately from the first housing portion comprising the heating element and the temperature sensor. In this regard, the heated sensor arrangement is at least configured for insertion of the first housing portion into the second housing portion. In one aspect, the first housing portion may be inserted into the second housing portion such that the second longitudinal axis of the second housing portion may coincide with the first longitudinal axis of the first housing portion. In other words, the first housing portion is configured to be inserted into an interior of the second housing portion. The first housing portion may be arranged coaxially in the second housing portion.

[0018] In general terms, when the first housing portion is inserted into the second housing portion, the first housing portion and the second housing portion may be in thermal contact. Further, when the first housing portion is inserted into the second housing portion, the second housing portion at least partially covers the first outer surface of the first housing portion. In other words, the outer circumferential surface of the first housing portion may be at least partially sheathed by the second housing portion. In yet other words, the first housing portion may be partially enclosed or housed inside the second housing portion. Preferably, the second housing portion covers a majority of an area of the first outer surface of the first housing portion. For example, the second housing portion may cover more than 80 % of an area of the first outer surface of the first housing portion. In one aspect, the second housing portion may fully cover the first outer surface of the first housing portion. In this regard and in other words, in one aspect the whole lateral first outer surface of the first housing portion may be covered by the second housing portion.

[0019] In addition, the second outer surface of the second housing portion comprises a supporting section extending along a portion of the second outer surface. Hence, the supporting section may be a portion of the second outer surface, for example a contact area configured to contact an evaporator tube, or the supporting section may cover the second outer surface. Therefore, the supporting section may radially protrude from the rest of the second outer surface, especially over a whole circumference. In either case, the supporting section may be integrally formed or separately formed from the second housing portion.

[0020] Further, the supporting section is configured to contact the evaporator tube. Consequently, the supporting section is configured to be in direct contact with an evaporator tube. In this regard, the supporting section may be configured to fittingly or snugly contact or abut a portion of a lateral outer tube surface of an evaporator tube. As aforementioned, the evaporator tube may be made of stain- less-steel, carbon-steel, copper, or aluminum for example. The supporting section may thus be in direct contact with the stainless-steel, carbon-steel, copper, or aluminum of the evaporator tube, when attached to an evaporator tube.

[0021] Providing a second housing portion, which is at least partially covering the first housing portion comprising the heating element and the temperature sensor, may help to ensure that the first housing portion is spaced apart from an evaporator tube when the heated sensor arrangement and more precisely the supporting section of the second housing portion is in contact with the evaporator tube. As a result, considering only the first housing portion and the second housing portion as a closed system, heat, which may initially only be introduced directly into the first housing portion by the heating element, may only be conducted to the second housing portion by heat conduction from the first housing portion.

[0022] In one aspect, the contact of the heating element on the lateral first inner surface completely in the circumferential direction may ensure that the first housing portion has at least almost the same, preferably the same, temperature in the circumferential direction. Not considering the second housing portion, the cylindrical shape of the first housing portion may further support the heat to flow as evenly or homogenously as possible within the first housing portion without significant heat sinks or the like.

[0023] In addition, only partially contacting the evaporator tube by the supporting section of the second housing portion may only lead to a substantially local heat flow from the heated sensor arrangement and more precisely from the second housing portion to the evaporator tube, resulting in a comparatively low, and preferably no, temperature gradient inside the first housing portion along the first longitudinal axis. Especially arranging the temperature sensor offset the supporting section may therefore additionally decrease the local influences on the supporting section by the evaporator tube detectable by the temperature sensor. In addition, not having or only having a comparatively low temperature gradient inside the first housing portion, may allow to detect a temperature by the temperature sensor which may only be slightly below a temperature that the temperature sensor would detect without the supporting section contacting the evaporator tube. In this regard, not having or only having a low temperature gradient allows the temperature sensor to be arranged in any rotational position without having a negative effect on the temperature measurement. In other words, the rotational position is irrelevant for the accuracy of the temperature measurement. In yet other words, it does not matter whether the temperature sensor is facing towards or away from the evaporator tube when the heated sensor arrangement is installed to the evaporator tube. This effect may especially be helpful during assembly and manufacturing of the heated sensor arrangement. A temperature measurement by the heated sensor arrangement may thus be improved.

[0024] Furthermore, and as aforementioned, arranging the temperature sensor offset along the first longitudinal axis relative to the supporting section may support the improved temperature detection as a locally larger temperature gradient near the supporting section only has a minor influence on the temperature detected in the area of the temperature sensor. Since the detected temperature is relevant for determining a share of liquid in a refrigerant flow, this information can be obtained with improved accuracy, for example by a control unit processing a respective sensor signal.

[0025] In one aspect, the first housing portion may be made of a first material and the second housing portion may be made of a second material, wherein the second material is different from the first material. The first material may be a metallic material. The second material may be another metallic material.

[0026] In one embodiment, the second housing portion may comprise a higher heat conductivity than the first housing portion. In other words, a material of the second housing portion may comprise a higher heat conductivity compared to a material of the first housing portion. The use of different heat conductivities for the first housing portion and the second housing portion, wherein the heat conductivity of the second housing portion is higher than that of the first housing portion, enables a more even distribution of heat within the first housing portion, particularly in an area of the lateral first inner surface of the interior of the first housing portion. Due to its lower heat conductivity compared to the second housing portion, the first housing portion acts as a kind of insulation or filter that dampens the influences acting on the second housing portion to a certain extent. In other words, influences acting on the lateral first outer surface of the first housing portion may have a smaller influence on the lateral first inner surface of the first housing portion and thus on the temperature sensor which is arranged inside the first housing portion. At the same time, the higher heat conductivity of the second housing portion increases the sensitivity of the second housing portion when in contact with the evaporator tube. In other words, contact between the second housing portion and the evaporator tube leads to a better heat transfer via the supporting section and thus to a more visible temperature gradient within the second housing portion and also to an influence on the first housing portion. In summary, choosing a higher heat conductivity for the second housing portion compared to the first housing portion may improve detection of the temperature by the heated sensor arrangement.

[0027] In a further embodiment, a heat conductivity of the second housing portion may be at least three times a heat conductivity of the first housing portion. In other words, a material of the second housing portion may be at least three times a heat conductivity of a material of the first housing portion. In this regard, the first housing portion is preferably made of a material, for example steel or stainless-steel, and / or the second housing portion is made of aluminum material. Aluminum material may include aluminum and aluminum-based alloys. The "filter properties" of the first housing portion described above may be intensified by using materials with higher differences in heat conductivity. In addition, "sensitivity properties" of the second housing portion described above may be intensified by using a material with a comparatively high heat conductivity.

[0028] In addition or alternatively, the heating sensor arrangement may further comprise a tubular third housing portion for insertion of the second housing portion such that the third housing portion at least partially encloses the second outer surface of the second housing portion. Preferably the third housing portion is arranged in an area along the first longitudinal axis where the temperature sensor is arranged. The third housing portion may thus be configured to protect the heated sensor arrangement at least in an area where the temperature sensor is arranged. In other words, the third housing portion may be configured to protect the temperature sensor from external influences on the temperature sensor. In yet other words, a local influence at the supporting section which may have an influence on the second housing portion and the first housing portion at the contact area between an evaporator tube and the supporting section, may result in an almost homogenic temperature profile in an area where the temperature sensor is arranged. In this regard, the first housing portion may preferably be covered by the second housing portion and the third housing portion in an area along the first longitudinal axis where the temperature sensor is arranged.

[0029] In one aspect, the second housing portion and the third housing portion may be arranged so that a third longitudinal axis of the third housing portion coincides with the first longitudinal axis and / or the second longitudinal axis.

[0030] In one aspect, the third housing portion may not be configured to be rotated with respect to the second housing portion, when the second housing portion is inserted into the first housing portion. In this regard, the third housing portion may comprise third orientation means engaging second orientation means of the second housing portion when the second housing portion is inserted into the third housing portion.

[0031] In a further aspect, the third housing portion may fully cover the lateral second outer surface of the second housing portion except for the supporting section. In yet a further aspect, the third housing portion may at least fully cover the lateral second outer surface in an area between an end face of the second housing portion, in a direction where the temperature sensor is arranged, and the supporting section. Arrangement of the second housing portion inside the third housing portion may thus improve the heated sensor arrangement and especially protect the temperature sensor.

[0032] In one embodiment, the third housing portion may comprise a lower heat conductivity than the first housing portion and / or a lower heat conductivity than the second housing portion. Preferably the third housing portion comprises a heat conductivity of less than 1 W / (m*K). In one aspect, the third housing portion may be provided by a polymer material. The third housing portion may therefore act as a kind of insulation and support targeted heat dissipation via the supporting section. Further, the third housing portion may decrease environmental influences on the second housing portion. Furthermore, the third housing portion may thus help to optimize the temperature measurement within the first housing portion by the temperature sensor. In a further aspect, the evaporator tube may additionally be in contact with the third housing portion, for example with auxiliary supporting sections) and / or auxiliary receiving section(s), which may facilitate attachment of the heated sensor arrangement to the evaporator tube. Still using a low heat conductivity for the third housing portion allows to limit the influences of this contact between the evaporator tube and the third housing portion to an insignificant level.

[0033] According to a further embodiment, the heated sensor arrangement may comprise an insert arranged inside the interior of the first housing portion. The insert may thus be inserted into the first housing portion. The temperature sensor may be arranged in a recess of the insert. During manufacturing, the temperature sensor may thus be placed in the insert first and may then be inserted together with the insert in the first housing portion. The insert may comprise a substantially cylindrical form. The insert may further be configured to allow electrical connection between electrical leads of a power source to the heating element. For example, the insert may comprise respective through bores, channels, grooves or recesses allowing electrical leads to pass, for example pass through, the insert to the heating element. Alternatively, the insert may be equipped with electrically conductive components configured to electrically connect the electric leads to the heating element. In this regard, electrical connections may protrude from an end face of the heating element.

[0034] The insert may additionally or alternative have a lower heat conductivity than the first housing portion. The insert may for example comprise a polymer material. The insert may allow for direct contact between the temperature sensor and the lateral first inner surface of the first housing portion, when the temperature sensor is arranged in the recess of the insert and the insert is inserted into the first housing portion. However, according to a preferred aspect, the temperature sensor is not contacting the lateral first inner surface of the first housing portion although the temperature sensor is positioned in the recess. In other words, preferably there is no direct contact between the temperature sensor and the first inner surface. In this regard, the insert may be surrounded by a layer. In one aspect, the insert may be surrounded by a layer of crimp flex. In one aspect, the layer may comprise a thickness of for example 0.1 mm. In one aspect, the layer may be configured to prevent contact between, for example, wires arranged inside the insert and the lateral inner surface of the first housing portion. In addition or alternatively the insert may at least be partially arranged between the heating element and the temperature sensor. Consequently, the insert, especially if it has a very low heat conductivity, for example similar to the one of the third housing portion, may shield the temperature sensor from the heating element so that the temperature measurement can be further optimized. In this regard, the insert may even be in direct contact with the heating element.

[0035] In one additional embodiment, the first housing portion may comprise a first end face and a second end face opposite to the first end face along the first longitudinal axis. The supporting section may be arranged closer to the first end face than to the second end face. The temperature sensor may be arranged closer to the second end face. A distance between the temperature sensor and the supporting section may thus allow for improved temperature measurement by the temperature sensor since the first housing portion may now be configured to provide an improved filter as mentioned before.

[0036] In a further aspect, the heated sensor arrangement may be configured such that when the first housing portion may be inserted into the second housing portion, the heating element may be arranged relative to the supporting section such that a radial direction with respect to the second longitudinal axis intersects both the supporting section and the heating element. In other words, the heating element and the supporting section overlap (at least partially) along the first longitudinal axis and / or the second longitudinal axis. An axial position of the supporting section may match or coincide with an axial position of the heating element. The axial positions may be defined with respect to the first longitudinal axis and / or the second longitudinal axis. Further, the first end face may be a closed first end face as aforementioned. The heating element may be in contact with the first end face in the interior of the first housing portion. An overlapping arrangement between the heating element and the supporting section allows to provide an increased temperature gradient between the heating element and a point of contact with the evaporator tube without, for example, large heat losses to the environment. The temperature measurement may thus be additionally improved. In this regard, the temperature sensor, which is arranged offset with respect to the supporting section along the first longitudinal axis, may be additionally arranged opposite to the supporting section being in contact with the evaporator tube in a radial direction perpendicular to the first longitudinal axis. In this regard, a radial distance between the temperature sensor and the supporting section, i.e. a distance in a direction perpendicular to the first longitudinal axis, may be increased such that a heat dissipation via the supporting section to the evaporator tube has less interference on the temperature measurement. However, as mentioned before, due to the inventive concept of the heated sensor arrangement, the rotational position of the temperature sensor has no or only a very small significance which can be neglected.

[0037] In one embodiment the supporting section of the second housing portion may comprise at least one receiving section configured to contact the evaporator tube. The receiving section may be formed such that an outer surface of the evaporator tube may be received in the receiving section in such a way that the receiving section partially contacts the outer surface in the circumferential direction of the evaporator tube. The receiving section may therefore have a semi-circular shape when viewed in cross-section, which is adapted to a specific evaporator tube diameter. The receiving section may therefore enable surface contact between the supporting section and the evaporator tube.

[0038] In one aspect, a first distance between the receiving section and the second longitudinal axis of the second housing portion may be greater than a second distance between the second longitudinal axis of the second housing portion and the second outer surface of the second outer portion. In other words, the supporting section may radially protrude from the rest of the second outer surface. This may ensure that only the supporting section of the second housing portion is in contact with the evaporator tube. In addition, the first distance and the second distance may be measured radially with respect to the second longitudinal axis.

[0039] According to one embodiment the supporting section may be configured to contact evaporator tubes of at least more than one, preferably three, different diameters. In this regard, the supporting section may comprise a specific, i.e. an indu- vial, receiving section for each diameter. In other words, the supporting section may for example comprise three different receiving sections for three different evaporator tube diameters. However, the supporting section could also comprise for example four different receiving sections for four different evaporator tube diameters. In one aspect, the supporting section may for example comprise a first receiving section for a first evaporator tube diameter of about 10 mm, a second receiving section for a second evaporator tube diameter of about 12 mm and a third receiving section for a third evaporator tube diameter of about 16 mm. In one aspect, the supporting section may comprise two different receiving sections for two different evaporator tube diameters. In this regard, the supporting section may for example a first receiving section for a first evaporator tube diameter of about 22 mm and a second receiving section for a second evaporator tube diameter of 27 mm. Independent on the number of receiving sections, however, the heated sensor arrangement may thus be rotated about the first longitudinal axis for relative orientation of the heated sensor arrangement with respect to the evaporator tube. Comprising different receiving section for different evaporator tube diameters may improve the surface contact for evaporator tubes comprising different evaporator tube diameters.

[0040] Additionally or alternatively, the receiving sections may be arranged evenly, i.e. regularly, around a circumferential direction about the second longitudinal axis. In other words, respective center positions of the receiving sections along the circumferential direction may be arranged equidistantly along the circumferential direction. Nevertheless, an extension of the receiving sections, which are configured for different evaporator tube diameters, can be of different lengths.

[0041] In one aspect, first distances between the receiving sections and the second longitudinal axis measured radially with respect to the second longitudinal axis may be equal for all receiving sections. Hence, first distances between center positions of the receiving section and the second longitudinal axis measured radially with respect to the second longitudinal axis may be equal for all receiving sections. In other words, first distances between the receiving sections and the second longitudinal axis may be equidistant. Since the first distances have a same length, the distance to the lateral first outer surface of the first housing portion and to the lateral first inner surface is preferably also equal for all receiving sections. Furthermore, a shortest distance to the heating element is preferably also equal for all receiving sections, so that the heat emitted by the heating element is required to penetrate an equal amount of material layers and material thickness in order to reach the evaporator tube. This makes the heated sensor arrangement at least almost equally accurate for different evaporator tube diameters.

[0042] In a further embodiment, the first housing portion may comprise a first outer diameter of between 4 mm and 14 mm. In this regard, the first outer diameter is preferably the same in an area along the first longitudinal axis where the temperature sensor and the heating element are arranged. A wall thickness of the first outer portion may be in between 0.3 mm and 2.0 mm. In addition, or alternatively, the first housing portion may comprise a length of between 40 mm and 100 mm. The length is preferably measured between the first end face and the second end face along the first longitudinal axis. Further, additionally or alternatively, the second housing portion excluding the supporting section may comprise a wall thickness of between 0.3 mm and 2.5 mm. In other words, the second housing portion may have a wall thickness of between 0.3 mm and 2.5 mm outside the supporting section. Additionally or alternatively, the supporting section may have a supporting length measured along the second longitudinal axis of between 1 mm and 20 mm. In this regard, the supporting section may extend along the lateral second outer surface by said supporting length. In one aspect, the supporting length may thus be between one hundredth and half of the length of the first housing portion. Additionally, or alternatively, a supporting diameter defining a maximum diameter of the supporting section of between 10 mm and 50 mm. Half of the supporting diameter may thus be greater than first distance(s). The dimensions given are preferred dimensions which, however, do not necessarily have to be complied with in order to make use of the invention.

[0043] In one embodiment, the heating element may comprise a heating element diameter. Considering the aforementioned maximum first outer diameter of 14 mm and a wall thickness of the first housing portion, according to one aspect, the heating element diameter may at least be less than 14 mm. Further, a ratio between the supporting diameter and the heating element diameter may be greater than or equal to 3 and less than or equal to 4. The ratio between the supporting diameter and the heating element diameter may be referred to as "first ratio". For example, if the supporting diameter is 12 mm, the heating element diameter may be between 3 mm and 4 mm.

[0044] In a further embodiment, the heating element may comprise a heating element length measured along the first longitudinal axis. Considering a length of the first housing portion and the fact that the heating element is arranged inside the first housing portion together with the temperature sensor, the heating element length must be less than the first housing portion. Further, a ratio between the heating element length and the supporting length may be greater than or equal to 0.5 and less than or equal to 4. The ratio between the heating element length and the supporting length may be referred to as "second ratio". Thus, considering a supporting length of 10 mm which would be in a range of 1 mm and 20 mm as aforementioned, the heating element length may be between 5 mm and 40 mm.

[0045] Furthermore, in one embodiment, a ratio between the supporting diameter and the first distance may be greater than or equal to 2 and less than or equal to 5. The ratio between the supporting diameter and the first distance may be referred to as "third ratio". For example, considering a supporting diameter of 10 mm as aforementioned, the first distance may be between 2 mm and 5 mm. However, considering for example a supporting diameter of 50 mm as aforementioned, the first distance may be between 10 mm and 25 mm.

[0046] The first, second and third ratios may define further preferred relative dimensions between the parts of the heated sensor arrangement. Applying these ratios may result in the most accurate temperature measurements. However, the temperature measurements may also be affected by for example the temperature of the refrigerant and the wall thickness of the evaporator tube. Consequently, other ratios may exist that make use of the invention and may be equally suitable in different conditions.

[0047] According to a further aspect of the invention, the heating element may have a maximum power consumption of less than 15 W. Preferably the heating element may have a maximum power consumption of 14 W, for example a power consumption of 14 W or less than 14 W. Due to the comparatively small amount of power consumption, the heating element could even be supplied by power of a portable power source such as a battery. In addition, the heating element may be comparatively small, which also facilitates installation of a heated sensor arrangement comprising the respective heating element. In addition or alternatively, the heating element may be configured to be heated up to a maximum temperature of about 90 °C. The power source may preferably be an electric power source providing AC or DC voltage of equal to or less than 24 V. Electric leads and the corresponding cable of the power source may be inserted into the first housing portion from one side of the first housing portion and may additionally be provided with a cable relief. A connection between the cable relief and the first housing portion may be preferably at least IP67 waterproof.

[0048] According to a further aspect of the invention, the object may be solved by an arrangement for detecting, at an evaporator of a refrigerant circuit with at least one evaporator tube, a share of liquid in a flow of refrigerant inside the at least one evaporator tube. A corresponding evaporator may have multiple evaporator tubes, wherein the arrangement and especially the heated sensor arrangement may be attached to according to the aforementioned aspects. In this regard, the arrangement may thus comprise a heated sensor arrangement according to the aforementioned aspects installed to an outer surface of the at least one evaporator tube. In addition, the arrangement comprises an additional temperature sensor arrangement installed to the at least one evaporator tube and / or another evaporator tube of the evaporator.

[0049] The additional temperature sensor arrangement and the heated sensor arrangement may thus be installed to same or different evaporator tubes. Further, a control unit may form part of the arrangement. The control unit may be configured to receive sensor signals of the heated sensor arrangement and the additional temperature sensor arrangement. Further, the control unit may be configured to calculate the share of liquid in the flow of refrigerant inside the evaporator tube based on the sensor signals, i.e. based on the sensor signal from the heated sensor arrangement and the sensor signal from the additional temperature arrangement. The control unit may further be configured to control a pump or valves forming part of the refrigerant circuit in order to improve for example energy efficiency or amount of refrigerant, for example of ammonia, needed or pumped through the refrigerant circuit. The control unit may thus control the amount of refrigerant supplied to the evaporator.

[0050] The heated sensor arrangement may be installed to the evaporator tube using a clamp. For example, the heated sensor arrangement may be retrofitted to an already installed evaporator. The evaporator tube to which the heated sensor arrangement may be installed, may preferably be arranged substantially horizontally. In other words, a longitudinal axis of the evaporator tube and the direction of gravity are preferably almost perpendicularly arranged. In one aspect, substantially horizontally may mean that an angle between the longitudinal axis of the evaporator tube and the direction of gravity is between 85° and 95°. Further, the heated sensor arrangement may be installed to a substantially horizontally evaporator tube such that an axis running in a radial direction perpendicular to a longitudinal axis of the evaporator tube and intersecting the first longitudinal axis forms an angle of between 25° and 35°, preferably an angle of 30°, with the direction of gravity. In this regard, installing the heated sensor arrangement so that the direction of gravity would run through the temperature sensor would be considered 0°, if the heated sensor arrangement would be installed below the evaporator tube, and 180°, if the heated sensor arrangement would be installed above the evaporator tube. When the heated sensor arrangement is oriented with respect to the evaporator tube according to the aforementioned angle, the heated sensor arrangement may be considered in an oriented state. In this oriented state, a statement about a share of liquid in a flow of refrigerant can be most accurate.

[0051] Additional features, advantages and possible applications of the invention result from the following description of exemplary embodiments and the drawings. All the features described and / or illustrated graphically here form the subject matter of the invention, either alone or in any desired combination, regardless of how they are combined in the claims or in their references back to preceding claims.

[0052] Preferred embodiments of the invention will now be described with reference to the drawings, in which:

[0053] Fig. 1 A shows an exploded view of a first housing portion of a heated sensor arrangement comprising a heating element, a temperature sensor and an insert and additionally showing a cable relief and a cable and electric leads;

[0054] Fig. 1 B shows a side view of the components shown in Fig. 1 A in an assembled state;

[0055] Fig. 1 C shows a sectional view of Fig. 1 B along line A-A;

[0056] Fig. 2 shows an exploded view of a heated sensor arrangement comprising a first housing portion according to Fig. 1A to 1 C, a second housing portion and a third housing portion;

[0057] Fig. 3 shows a first exemplary clamp for installing the heated sensor arrangement to an evaporator tube;

[0058] Fig. 4A shows a heated sensor arrangement installed to an evaporator tube by means of the clamp according to Fig. 3;

[0059] Fig. 4B shows a side view of Fig. 4A;

[0060] Fig. 4C shows a sectional view of Fig. 4B; Fig. 4D shows a front view of Fig. 4B, wherein the heated sensor arrangement is in an oriented state with respect to the evaporator tube;

[0061] Fig. 5A shows an exemplary third housing portion of a heated sensor arrangement to be used with a clamp shown in Fig. 6A;

[0062] Fig. 5B shows a front view of the third housing portion depicted in Fig. 5A;

[0063] Fig. 5C shows a sectional view of the third housing portion along line C-C depicted in Fig. 5A;

[0064] Fig. 6A shows a perspective front view of a second exemplary clamp in a secured closed state;

[0065] Fig. 6B shows a side view of the clamp shown in Fig. 6A;

[0066] Fig. 6C shows a sectional view along line B-B depicted in Fig. 6B; and

[0067] Fig. 7 shows an exemplary evaporator provided with a heated sensor arrangement.

[0068] In the Figures, identical elements and components as well as identical elements and components in different examples or embodiments, i.e. elements and components acting identical or provided for the same purposes but belong to different examples, are provided with the same reference signs.

[0069] Figure 1 A depicts a cylindrical first housing portion 10 of a heated sensor arrangement 1 comprising a lateral first outer surface 11 extending between a first end face 12 and a second end face 13 opposite to the first end face 12. In the example shown in Fig. 1A, the first end face 12 is closed. An interior 14 of the first housing portion 10 may thus be only accessible via an opening in the second end face 13.

[0070] The first housing portion 10 extends along a first longitudinal axis X. A heating element 100 and an insert 200 may be arranged with respect to the first longitudinal axis X inside the first housing portion 10. In this regard, the heating element 100, which comprises a substantially cylindrical form, may be inserted into the first housing portion 10 by moving the heating element 100 along the first longitudinal axis X. In addition, the insert 200 may be inserted into the first housing portion 10 by moving the insert 200 along the first longitudinal axis X.

[0071] Two electrical connections 101 are electrically connected to the heating element 100 shown in Fig. 1A and configured to be inserted into the insert 200. The electrical connections 101 may be used to orientate the insert 200 with respect to the heating element 100. A temperature sensor 201 may be inserted or arranged into a recess 202 of the insert 200. The assignment of the temperature sensor 201 to the insert 200 is indicated by a dashed line.

[0072] As shown in Fig. 1 C, the heating element 100 and the insert 200 may be in contact with a lateral first inner surface 15 of the interior 14 of the first housing portion 10. The heating element 100 and the insert 200 may all be arranged along the first longitudinal axis X. Although not required, the temperature sensor 201 , which may be a PT1000 element, is also in direct contact with the lateral first inner surface 15 of the first housing portion 10. However, as aforementioned, preferably there is no direct contact between the lateral first inner surface 15 and the temperature sensor 201 .

[0073] The opening of the first housing portion 10 at the second end face 13 is closed in Figs. 1 B to 1 C by a cable relief 300 in which a cable 301 with four electric leads 302 is arranged. The electric leads 302 may be used to power the heating element 100 and to transmit a sensor signal from the temperature sensor 201 from the first housing portion 10 to a device, for example a control unit 500, as for example shown in Fig. 7. In this regard, a pair of electric leads 302 may thus be used for the temperature sensor 201 and the other electric leads 302 may be used for the heating element 100.

[0074] The insert 200 may be made of a polymer material but may be configured to electrically connect the electric leads 302 to the electrical connection 101 of the heating element 100. When the cable relief 300 is used to close the first housing portion 10 as shown in Fig. 1 B, a waterproof device being IP67 waterproof may be created.

[0075] In this assembled state shown in a sectional view in Fig. 1 C, the heating element 100 is arranged closer to a first end of the first housing portion 10, i.e. closer to the first end face 12 than to the second end face 13. In this regard, the heating element 100 comprises a heating element length L100 measured along the first longitudinal axis X and a heating element diameter D100. The heating element length L100 shown here is greater than the heating element diameter D100 and shorter than a length L10 of the first housing portion 10. Further, the heating element diameter D100 is smaller than diameter of the first housing portion 10. Consequently, the heating element 100 is configured to be arranged in the interior 14 of the first housing portion 10.

[0076] The heating element 100 may be configured to provide heat, when electric power is supplied to the heating element 100 and a temperature of for example a heating coil 102 arranged between two portions 102A of textile material is increased. The heat generated by the heating element 100 is then transferred to the first housing portion 10 and more precisely to the lateral first inner surface 15 of the first housing portion 10, so that the first housing portion 10 heats up. For example, the heating element 100 may heat up to 90 °C, so that in an ideal case, in which the first housing portion 10 would not give off any heat to other elements and the environment, it would also assume a heat of 90 °C. The first housing portion 10 is preferably made of a material, for example steel, in one aspect for example stainless steel, which has a lower heat conductivity than a tubular second housing portion 20, which is shown in Fig. 2. The second housing portion 20 may preferably be made of aluminum.

[0077] The tubular second housing portion 20 comprises a lateral second outer surface 21. Further, the second housing portion 20 extends along a second longitudinal axis Y between a third end face 22 and a fourth end face 23. For the example shown in Fig. 2, when the first housing portion 10 is inserted into a second interior 24 of the second housing portion 20, the second longitudinal axis Y and the first longitudinal axis X coincides. The second housing portion 20 may be made of a material with a higher heat conductivity than the first housing portion 10. The material of the second housing portion 20 may for example be aluminum.

[0078] As can be noticed from Fig. 2, a supporting section 25 extends along a portion of the second outer surface 21 . Here, the supporting section 25 even extends on the second outer surface 21. To be more precise, the supporting section 25 extends over a supporting length L25 which is only a portion of the full length of the second housing portion 20 between the third end face 22 and the fourth end face 23.

[0079] In addition, the supporting section 25 radially protrudes from the rest of the second outer surface 21. The supporting section 25 comprises three receiving sections 26 arranged evenly, i.e. regularly, around a circumferential direction about the second longitudinal axis Y. Each of the receiving sections 26 is configured to receive or contact an evaporator tube 1000, 1000A of an evaporator 1001 comprising a different diameter. When the heated sensor arrangement 1 is installed to an evaporator tube 1000, 1000A, however, only one of the receiving sections 26 should be contacting the respective evaporator tube 1000, 1000A as for example shown in Figs. 4A to 4D.

[0080] In the example shown in Fig. 2 also a tubular third housing portion 30 extending along a third longitudinal axis Z is shown. The third housing portion 30 comprises two auxiliary supporting sections 31 each arranged at end faces of the third housing portion 30. As can be noted from a number "12" marked on a lateral third outer surface 32 of the third housing portion, corresponding auxiliary receiving sections 33 arranged with respect to this number are designed for an evaporator tube diameter of 12 mm. In other words, an evaporator tube having a diameter of 12 mm may best be used with corresponding auxiliary receiving sections 33.

[0081] In order to align a correct receiving section 26 configured to receive a 12 mm diameter evaporator tube with the auxiliary receiving sections 33, the third housing portion 30 comprises third orientation means 34 and the second housing portion 20 comprises second orientation means 27 configured to come into engagement, when the second housing portion 20 is inserted into the third housing portion 30. A correspondingly assembled heated sensor arrangement 1 with a first housing portion 10, a second housing portion 20 and a third housing portion 30, wherein all three longitudinal axes X, Y and Z coincide is shown in Figs. 4A to 4D.

[0082] In this regard, the third housing portion 30 may for example be made of a polymer material and may comprise a lower heat conductivity than the materials of the first housing portion 10 and / or the second housing portion 20. In addition, it may be noted from Fig. 1 C or 4C, that when the third housing portion 30 is pushed over the second housing portion 20, in which the first housing portion 10 together with the heating element 100 and temperature sensor 201 is arranged, the third housing portion 30 covers in particular the region along the first longitudinal axis X in which the temperature sensor 201 is arranged. Here, in Figs. 4A to 4D, the second housing portion 20 fully covers the lateral first outer surface 11 of the first housing portion 10 and the third housing portion 30 partially covers the lateral second outer surface 21 of the second housing portion 20.

[0083] In order to install the heated sensor arrangement 1 to an evaporator tube 1000 as shown in Figs. 4A to 4D, a clamp 400 as shown in Fig. 3 is used. The clamp 400 for clamping the heated sensor arrangement 1 to the evaporator tube 1000 comprises a first part 401 with a first clamping portion 402 and a second part 403 with a second clamping portion 404. The first part 401 and the second part 403 are pivotable about a pivoting axis P relative to each other in order to transfer the clamp 400 from an open state as shown in Fig. 3 in a closed state.

[0084] In the closed state the first clamping portion 402 and the second clamping portion 404 together provide a through opening for receiving the heated sensor arrangement 1 and the evaporator tube 1000 to be clamped. In this regard, the heated sensor arrangement 1 may be pre-fixed, for example by positively locking, i.e. form fit, in the first clamping portion 402, when the clamp 400 is in the open state. In one aspect, the heated sensor arrangement 1 can still be rotated about the first longitudinal axis X when pre-fixed. However, in a preferred embodiment, rotation of the heated sensor arrangement 1 about the first longitudinal axis X is prevented after being pre-fixed. A corresponding embodiment of a clamp 400 and a third housing portion 30 of the heated sensor arrangement 1 is explained with respect to Figs. 5A to 6C.

[0085] The heated sensor arrangement 1 may thus be rotated so that the receiving section 26 configured for the diameter of the evaporator tube 1000 is accessible. The clamp 400 comprising the heated sensor arrangement 1 may then be brought into contact with the evaporator tube 1000, so that the evaporator tube 1000 contacts the receiving section 26 of the supporting section 25. The second part 403 of the clamp 400 may then be closed so that the evaporator tube 1000 and the heated sensor arrangement 1 are both caught between the first part 401 and the second part 403.

[0086] A clamping unit 405 may be used to bring the clamp 400 from the closed state in a secured closed state preventing unintentional transition to the open state. In this regard, the clamping unit 405 comprises a threaded rod 406 being coupled to the first part 401 by a dowel nut 407 and pivotable thereto about a rotational axis R.

[0087] A clamping element 408 is attached to the threaded rod 406 and rotatable with respect to the threaded rod 406 or together with the threaded rod 406. In this respect, the clamping unit 405 is configured to pull the first part 401 and the second part 403 of the clamp 400 together by rotating the clamping element 408 when the clamp 400 is in the secured closed state. By rotating the clamping element 408 the heated sensor arrangement 1 and the evaporator tube 1000 may thus be firmly clamped by tightening the first part 401 and the second part 403 together.

[0088] The heated sensor arrangement 1 clamped to the evaporator tube 1000 is shown in Figs. 4A to 4D. From Figs. 4B and 4C it may be noted that the evaporator tube 1000 and more precisely an outer surface 1002 of the evaporator tube 1000 contacts the receiving section 26 and the auxiliary receiving sections 33 of the heated sensor arrangement 1. Considering a low heat conductivity of the third housing portion 30 of for example less than 1 W / (m*K), heat emitted by the heating element 100 is transferred to the evaporator tube 1000 at least almost exclusively through the supporting section 25 and thus through the contact between the evaporator tube 1000 and the receiving section 26. Therefore, a temperature gradient is formed between the heating element 100 and the evaporator tube 1000, particularly in the area of the supporting section 25, i.e. in particular at a first distance d1 between the receiving section 26 and the second longitudinal axis Y measured radially with respect to the second longitudinal axis Y. As shown in Fig. 4D, the first distance d1 is greater than the second distance d2 between the second longitudinal axis Y and the second outer surface 21 of the second housing portion 20.

[0089] In Fig. 4D it may be noted that the clamp 400 comprises an alignment indicator 409. The alignment indicator 409 may be used to bring the clamp 400 and thus the arrangement of the heated sensor arrangement 1 and the evaporator tube 1000 into a desired orientation. In Fig. 4D it may be assumed that the alignment indicator 409 is arranged in parallel to a direction of gravity and pointing opposite to the direction of gravity. In this orientation, in which the evaporator tube 1000 is substantially horizontally arranged, the heated sensor arrangement 1 is oriented such that an axis, for example a tilting axis T, running in a radial direction perpendicular to a longitudinal axis E of the evaporator tube 1000 and intersecting the first longitudinal axis X and the longitudinal axis E forms an angle a of between 25° and 35°, preferably an angle of 30°, with the direction of gravity. Orientation in this oriented state, may allow for the most accurate statement about a share of liquid in a flow of refrigerant.

[0090] Further, in Fig. 4D a supporting diameter D25 defining a maximum diameter of the supporting section 25 is shown. Preferred relative dimensions of the heated sensor arrangement 1 may thus be defined by first, second and third ratios. In this regard, a first ratio may define a ratio between a supporting diameter D25 and a heating element diameter D100. A second ratio may define a ratio between the heating element length L100 and the supporting length L25. And a third ratio may define a ratio between the supporting diameter D25 and the first distance d1 . The different diameters, lengths and distances are preferably chosen so that the aforementioned limits of the ratios are met.

[0091] An alternative example of a third housing portion 30 of a heated sensor arrangement 1 is shown in Figs. 5A to 5C. This third housing portion 110 is particularly suitable for use with a clamp 400 shown in Figs. 6A to 6C. In this regard, the lateral third outer surface 32 used for clamping is configured to be received in the first clamping portion 402 of the clamp 400 and comprises first fixation means 35. The first fixation means 35 here are provided by a protrusion extending along the third longitudinal axis Z of the third housing portion 30. More precisely, the protrusion may be a flange extending along the lateral third outer surface 32 of the third housing portion 30.

[0092] Further, as already explained with respect to the third housing portion 30 not having first fixation means 35, also the third housing portion 30 shown here in Figs. 5A to 5C comprises two auxiliary supporting sections 31 each comprising three auxiliary receiving sections 33. When the evaporator tube 1000 is brought into contact with the heated sensor arrangement 1 , the evaporator tube 1000 may not only be received in the receiving section 26 of the supporting section 25, for example provided by a second housing portion 20, but also in the auxiliary receiving sections 33 provided by the third housing portion 30. In this regard, the third housing portion 30 may comprise orientation means 34 configured to engage for example with corresponding means of the second housing portion 20 in order to prevent relative rotation between the second housing portion 20 and the third housing portion 30. Here, also orientation means 34 on the inside of the third housing portion 30 are shown. When the orientation means 34 are engaged, the auxiliary receiving sections 33 and the receiving sections 26 may be aligned.

[0093] As can best be seen from Figs. 5B and 5C, the third housing portion 30 comprises three auxiliary receiving sections 33, each of which is preferably used for a different evaporator tube diameter. As can be noted from a number "12" marked on the lateral third outer surface 32, corresponding auxiliary receiving sections 33 arranged with respect to this number are designed for an evaporator tube diameter of 12 mm. In other words, an evaporator tube 1000 having a diameter of 12 mm may best be used with corresponding auxiliary receiving sections 33. In addition, the third housing portion 30 comprises as many first fixation means 35 as auxiliary receiving sections 33. Consequently, the third housing portion 30 may be pre-fixed in three different orientations, wherein in each of these orientations one of the first fixation means 35, i.e. one of the protrusions, engages with second fixation means 410 of the clamp 400 described with respect to Figs. 6A to 6C. In other words, the number of protrusions arranged on the lateral third outer surface 32 corresponds to a number of auxiliary receiving sections 33, which is identical to the number of receiving sections 26 of the supporting section 27. The first fixation means 35 may thus define predefined rotational positions in which the heated sensor arrangement 1 may be pre-fixed in the first clamping portion 402 of the clamp 400 shown in Figs. 6A to 6c, i.e. in which the first fixation means 35 and the second fixation means 410 are in engagement. When being engaged, relative rotation between the heated sensor arrangement 1 about the first longitudinal axis X and the first clamping portion 402 is prevented.

[0094] In an alternative embodiment of the clamp 400 shown in Figs. 6A to 6C and configured to be used with the aforementioned third housing portion 30, the clamp 400 and more precisely the first clamping portion 402 of the first part 401 of the clamp 400 comprises second fixation means 410. Here, the second fixation means 410 are provided by a recess or groove. Further, the second fixation means 410 are arranged at a center position of the first clamping portion 402. The second fixation means 410 may thus be used to prevent rotation of a pre-fixed heated sensor arrangement 1 and especially of the third housing portion 30 relative to the first clamping portion 402 of the first part 401 of the clamp 400. In this regard, the heated sensor arrangement 1 may thus be oriented with respect to the first clamping portion 402 before being pre-fixed.

[0095] The rotational fixation of the third housing portion 30 and thus of the heated sensor arrangement 1 , when being prefixed, may facilitate to bring the clamp 400 together with the pre-fixed heated sensor arrangement 1 in orientation with respect to the evaporator tube 1000 as the heated sensor arrangement 1 may be prevented from rotation. In other words, a receiving section 26 and / or an auxiliary receiving section 33 may not rotate out of a preferred orientation while trying to make contact between the clamp 400 with the pre-fixed heated sensor arrangement 1 and the evaporator tube 1000.

[0096] Further, as can be noted from Figs. 6A to 6C, although the clamping element 408 may be rotated by hand without using a tool, in one aspect, the clamping element 408 may also be rotated using a hexagon bit or an Allen key which may be inserted into a recess 411 of the clamping element 408, which may be a hexagonal recess, to rotate the clamping element 408. The clamping element 408 may thus be rotated to secure the heated sensor arrangement 1 to an evaporator tube 1000.

[0097] When being installed to an evaporator tube 1000, for example by a clamp 400, the heated sensor arrangement 1 may be used as shown in Fig. 7 to determine a share of liquid in a flow of refrigerant. In this regard, the heated sensor arrangement 1 is installed to an evaporator tube 1000 according to the aforementioned description, for example by a clamp 400. The evaporator 1001 shown in Fig. 7 comprises multiple evaporator tubes, from which evaporator tubes 1000 and 1000A are indicated with a reference sign. An air flow 1003 of a ventilator 1004 may thus come into thermal contact with the evaporator tubes.

[0098] The evaporator 1001 shown in Fig. 7 is a bottom feed evaporator, which may be seen from the arrows pointing towards a common liquid inlet 1005 and out of a common liquid outlet 1006. The common liquid inlet 1005 and the common liquid outlet 1006 are both fluidically connected to a collecting conduit 1007 collecting or distributing the refrigerant from and to the evaporator tubes. The refrigerant may thus pass from the common liquid inlet 1005 through the evaporator tubes to the common liquid outlet 1006. Further components and elements of the refrigerant circuit are not shown.

[0099] In Fig. 7 the heated sensor arrangement 1 is installed to the most loaded evaporator tube 1000 and an additional temperature sensor 1008 is installed to a further evaporator tube 1000A. A control unit 500 is collecting sensor data from the heated sensor arrangement 1 and the additional temperature sensor 1008. In this regard, the dashed lines may indicate a data transfer, which may for example be conducted wirelessly or wired. Based on the sensor signals the control unit 500 may thus calculate the share of liquid in the flow of refrigerant and may adapt operation of the components and elements of the refrigerant circuit accordingly.

[0100] Due to the structure of the heated sensor arrangement 1 and the corresponding aforementioned aspects, the temperature measurement by the heated sensor arrangement 1 may be more accurate compared to known solutions so that determining the share of liquid may be improved.

[0101] The control unit 500 may thus be configured to improve control of the refrigerant flow. In this regard, the amount of refrigerant needed in a refrigerant circuit may be substantially reduced without significantly affecting temperature control by the refrigerant circuit.

[0102] List of reference signs

[0103] 1 heated sensor arrangement

[0104] 10 cylindrical first housing portion

[0105] 11 lateral first outer surface

[0106] 12 first end face

[0107] 13 second end face

[0108] 14 interior

[0109] 15 lateral first inner surface

[0110] 20 tubular second housing portion

[0111] 21 lateral second outer surface

[0112] 22 third end face

[0113] 23 fourth end face

[0114] 24 second interior

[0115] 25 supporting section

[0116] 26 receiving section

[0117] 27 second orientation means

[0118] 30 tubular third housing portion

[0119] 31 auxiliary supporting section

[0120] 32 lateral third outer surface

[0121] 33 auxiliary receiving sections

[0122] 34 third orientation means

[0123] 35 first fixation means

[0124] 100 heating element

[0125] 101 electrical connections

[0126] 102 heating coil

[0127] 102A portion (of textile material)

[0128] 200 insert

[0129] 201 temperature sensor

[0130] 202 recess

[0131] 300 cable relief 301 cable

[0132] 302 electric lead

[0133] 400 clamp

[0134] 401 first part

[0135] 402 first clamping portion

[0136] 403 second part

[0137] 404 second clamping portion

[0138] 405 clamping unit

[0139] 406 threaded rod

[0140] 407 dowel nut

[0141] 408 clamping element

[0142] 409 alignment indicator

[0143] 410 second fixation means

[0144] 411 recess

[0145] 500 control unit

[0146] 1000 evaporator tube

[0147] 1000A evaporator tube

[0148] 1001 evaporator

[0149] 1002 outer surface (of the evaporator tube)

[0150] 1003 air flow

[0151] 1004 ventilator

[0152] 1005 common liquid inlet

[0153] 1006 common liquid outlet

[0154] 1007 collecting conduit

[0155] 1008 additional temperature sensor a angle d1 first distance d2 second distance

[0156] L10 length (of the first housing portion)

[0157] D10 diameter (of the first housing portion) D25 supporting diameter

[0158] L25 supporting length

[0159] D100 heating element diameter

[0160] L100 heating element length E longitudinal axis (of the evaporator tube)

[0161] T tilting axis

[0162] X first longitudinal axis

[0163] Y second longitudinal axis

[0164] Z third longitudinal axis P pivoting axis

[0165] R rotational axis

Claims

Claims1. Heated sensor arrangement (1 ) for use with an evaporator tube (1000, 100A) of an evaporator (1001 ) of a refrigerant circuit, wherein the heated sensor arrangement (1 ) comprises: a cylindrical first housing portion (10) extending along a first longitudinal axis (X) and having a lateral first outer surface (11 ); a heating element (100) arranged inside the first housing portion (10); a temperature sensor (201 ) arranged inside the first housing portion (10); and a tubular second housing portion (20) having a lateral second outer surface (21 ); wherein the sensor arrangement (1 ) is configured for insertion of the first housing portion (10) into the second housing portion (20) such that the second housing portion (20) at least partially covers the first outer surface (11 ) of the first housing portion (10); characterized in that the second outer surface (21 ) of the second housing portion (20) comprises a supporting section (25) extending along a portion of the second outer surface (21 ) and configured to contact the evaporator tube (100), and wherein the temperature sensor (201 ) is arranged offset along the first longitudinal axis (X) relative to the supporting section (25).

2. Heated sensor arrangement (1 ) according to claim 1 , characterized in that the second housing portion (20) comprises a higher heat conductivity than the first housing portion (10).

3. Heated sensor arrangement (1 ) according to claim 2, characterized in that a heat conductivity of the second housing portion (20) is at least three times a heat conductivity of the first housing portion (10), and wherein preferably the firsthousing portion (10) is made of steel and / or the second housing portion (20) is made of aluminum material.

4. Heated sensor arrangement (1 ) according to any one of the preceding claims, characterized in that the heating sensor arrangement (1 ) further comprises a tubular third housing portion (30) for insertion of the second housing portion (20) such that the third housing portion (30) at least partially encloses the second outer surface (21 ) of the second housing portion (20), preferably in an area along the first longitudinal axis (X) where the temperature sensor (201 ) is arranged.

5. Heated sensor arrangement (1 ) according to claim 4, characterized in that the third housing portion (30) comprises a lower heat conductivity than the first housing portion (10) and / or a lower heat conductivity than the second housing portion (20), preferably a heat conductivity of less than 1 W / (m*K).

6. Heated sensor arrangement (1 ) according to any one of the preceding claims, characterized in that the heated sensor arrangement (1 ) comprises an insert (200) arranged inside an interior (14) of the first housing portion (10), wherein the temperature sensor (201 ) is arranged in a recess (202) of the insert (200), and / or wherein the insert (200) has a lower heat conductivity than the first housing portion (10), and / or wherein the insert (200) is at least partially arranged between the heating element (100) and the temperature sensor (201 ).

7. Heated sensor arrangement (1 ) according to any one of the preceding claims, characterized in that the first housing portion (10) comprises a first end face (12) and a second end face (13) opposite to the first end face (11 ) along the first longitudinal axis (X), wherein the supporting section (25) is arranged closer to the first end face (12) than to the second end (13), andwherein the heated sensor arrangement (1 ) is configured such that when the first housing portion (10) is inserted into the second housing portion (20), the heating element (100) is arranged relative to the supporting section (25) such that a radial direction with respect to the second longitudinal axis (Y) intersects both the supporting section (25) and the heating element (100).

8. Heated sensor arrangement (1 ) according to any one of the preceding claims, characterized in that the supporting section (25) of the second housing portion (20) comprises at least one receiving section (26) configured to contact the evaporator tube (100), wherein a first distance (d1 ) between the receiving section (26) and the second longitudinal axis (Y) is greater than a second distance (d2) between the second longitudinal axis (Y) and the second outer surface (21 ) of the second housing portion (20), and wherein the first distance (d1 ) and the second distance (d2) are measured radially with respect to the second longitudinal axis (Y).

9. Heated sensor arrangement (1 ) according to any one of the preceding claims, characterized in that the supporting section (25) is configured to contact evaporator tubes (100) of at least more than one, preferably three, different diameters, wherein the supporting section (25) comprises a specific receiving section (26) for each diameter, and wherein first distances (d1 ) between the receiving sections (26) and the second longitudinal axis (Y) measured radially with respect to the second longitudinal axis (Y) are equal for all receiving sections (26).

10. Heated sensor arrangement (1 ) according to any one of the preceding claims, characterized in that the first housing portion (10) comprises a first outer diameter (D10) of between 4 mm and 14 mm and / or a length (L10) of between 40 mm and 100 mm, and / or wherein the second housing portion (20) excluding thesupporting section (25) comprises a wall thickness of between 0.3 mm and 2.5 mm, and / or wherein the supporting section (25) has a supporting length (L25) measured along the second longitudinal axis (Y) of between 1 mm and 20 mm and / or a supporting diameter (D25) defining a maximum diameter of the supporting section (25) of between 10 mm and 50 mm.

11. Heated sensor arrangement (1 ) according to any one of the preceding claims, characterized in that the heating element (100) comprises a heating element diameter (D100), wherein a ratio between the supporting diameter (D25) and the heating element diameter (D100) is greater than or equal to 3 and less than or equal to 4.

12. Heated sensor arrangement (1 ) according to any one of the preceding claims, characterized in that the heating element (100) comprises a heating element length (L100) measured along the first longitudinal axis (X), wherein a ratio between the heating element length (L100) and the supporting length (L25) is greater than or equal to 0.5 and less than or equal to 4.

13. Heated sensor arrangement (1 ) according to any one of the preceding claims, characterized in that a ratio between the supporting diameter (D25) and the first distance (d1 ) is greater than or equal to 2 and less than or equal to 5.

14. Heated sensor arrangement (1 ) according to any one of the preceding claims, characterized in that the heating element (100) has a maximum power consumption of less than 15 W, preferably a maximum power consumption of 14 W, and / or wherein the heating element (100) is configured to be heated up to a maximum temperature of about 90 °C.

15. Arrangement for detecting, at an evaporator (1001 ) of a refrigerant circuit with at least one evaporator tube (1000, 1000A), a share of liquid in a flow ofrefrigerant inside the at least one evaporator tube (1000, 1000A), the arrangement comprising: a heated sensor arrangement (1 ) according to any one of claims 1 to 14 installed to an outer surface (1002) of the at least one evaporator tube (1000, 1000A); an additional temperature sensor arrangement (1008) installed to the at least one evaporator tube (1000) and / or another evaporator tube (1000A) of the evaporator (1001 ); and a control unit (500), wherein the control unit (500) is configured to receive sensor signals of the heated sensor arrangement (1 ) and the additional temperature sen- sor arrangement (1008), and wherein the control unit (500) is configured to calculate the share of liquid in the flow of refrigerant inside the evaporator tube (1000, 1000A) based on the sensor signals.

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