Temperature sensor and temperature probe for milk freezing point instrument

Abstract

The utility model discloses a temperature sensor for a milk freezing point instrument, which comprises a flexible insulating substrate and an insulating covering film, a sealed insulating space is formed between the flexible insulating substrate and the insulating covering film, a lead is arranged in the sealed insulating space, one end of the lead is connected with a thermosensitive chip, and the other end of the lead is connected with a temperature sensor. A heat blocking section with a narrowed section is arranged at one end, close to the thermosensitive chip, of the wire; an electromagnetic shielding layer is arranged on one side, far away from the wire, of the flexible insulating substrate; the widths of the flexible insulating substrate and the insulating covering film at the thermosensitive chip end are in a narrowed state; the temperature probe for the milk freezing point instrument comprises the temperature sensor, a shell and sealant, the two ends of the shell in the extending direction are open, the shell is in a gradually-narrowed annular thin shell shape, and a limiting table top is arranged on the periphery of the shell. According to the temperature sensor and the temperature probe for the milk freezing point instrument, the influence of external heat can be effectively reduced in the use process of the sensor, and the difficulty of batch production and processing can be reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to a temperature sensor and temperature probe for milk ice point instrument belong to ice point detection technical field. BACKGROUND

[0002] In the ice point detection field, the ability to accurately and quickly distinguish subtle temperature changes is the key to the success of ice point detection. The ice point refers to the temperature at which a substance (usually a liquid) changes from a liquid to a solid (i.e. freezes). For pure substances, the ice point is a fixed temperature value, at which the liquid and solid states reach a stable phase equilibrium. When a solute is added to a solvent, the ice point of the solution is usually lower than that of the pure solvent, which is called ice point depression or ice point reduction. According to Raoult's Law, the degree of ice point depression is directly proportional to the concentration of the solute. By monitoring the subtle changes in the ice point of the solution, an accurate assessment can be made. Therefore, it is particularly important to accurately, sensitively and quickly obtain the temperature change of the solution ice point for analysis and detection.

[0003] In actual use environment, the indication accuracy of ice point temperature should reach m℃ (1‰℃) level; during the ice point platform evaluation period, the temperature should be stable in a short period (≥20s), and the fluctuation should be less than 0.5m℃. During this period, a small amount of heat conduction outside the sample will cause detection error and failure. In combination with the above, ice point detection not only needs to select appropriate temperature-sensitive elements, but also needs to do a good job in heat blocking.

[0004] Thermistors are known for their high sensitivity, small size, easy molding, good stability, strong overload capacity and wide working range. The temperature chip prepared therefrom has good performance and can be divided into positive temperature coefficient (PTC) chip and negative temperature coefficient (NTC) chip, etc. The structure is composed of thermosensitive semiconductor, electrode pin and packaging shell, and can be connected to the circuit through the pin. The pin material can be made of metal such as Dumet wire and copper wire, which has good conductivity, thick and strong pin, good rigidity, can adapt to packaging operation, and is suitable for mass production, but the thick pin will bring too much external temperature influence. When the pin is bonded with the sensing element and the control circuit, the internal and external heat conduction is also conducted, which affects the temperature detection. During sample ice point detection, there is a temperature difference of more than 30℃ between the sample part and the external temperature. The large internal and external heat conduction will inevitably cause precision loss.

[0005] If too thin pins are used, the heat conduction can be effectively reduced, but it is not conducive to production. The temperature sensing element is prone to adhesion and fracture during subsequent packaging, causing short circuit and open circuit. The packaging material itself has tension which will pull the pin, making it difficult to ensure the insulation distance between the pins, resulting in low yield and high production difficulty.

[0006] In subsequent use, the chip will be processed in specific circuit, heat insulation, electromagnetic interference and other measures, and the structure is packaged and strengthened, and is bonded with more circuits, which inevitably produces physical contact, increases the heat capacity dead volume, increases the heat conduction probability, increases the overall thermal time constant, slows down the response speed, and reduces the resolution, sensitivity, stability and the like of detection.

[0007] Therefore, the prior art still has some defects in practical use. The utility model discloses a temperature sensor and temperature probe for milk ice point instrument

[0008] The temperature sensor and temperature probe for milk ice point instrument can effectively reduce the influence of external heat during use, and can reduce the difficulty of batch production and processing.

[0009] To solve the above technical problems, the utility model adopts the following technical scheme:

[0010] The temperature sensor for milk ice point instrument comprises a flexible insulating substrate and an insulating cover film, and a sealed insulating space is formed between the flexible insulating substrate and the insulating cover film.

[0011] Further, the thermosensitive chip is located inside the sealed insulating space.

[0012] Further, the thermosensitive chip is located outside the sealed insulating space.

[0013] Further, the thermal resistance section has a cross-sectional area less than 0.0016π mm2 and a length greater than or equal to 1 mm.

[0014] Further, the two ends of the wire are respectively provided with two conversion interfaces, one end of the two conversion interfaces near the thermosensitive chip is a welding disc surface, and the other end is a gold finger pin; the wire is arranged at a certain electrical distance, and the number of wires is the same as the number of electrodes of the thermosensitive chip.

[0015] Further, the flexible insulating substrate is provided with an electromagnetic shielding layer on the side away from the wire.

[0016] Further, the width of the flexible insulating substrate and the insulating cover film at the end of the thermosensitive chip is narrowed; the flexible insulating substrate and the insulating cover film are thin sheets with a thermal conductivity less than 0.2 W / (m·K).

[0017] The temperature probe for milk ice point instrument comprises the temperature sensor.

[0018] Further, the shell is provided with a limiting platform on the periphery of the shell.

[0019] Further, the temperature sensor penetrates the two openings of the shell, and a temperature measuring part of the temperature sensor penetrates out of the smallest narrow opening of the shell; the sealant is filled in a gap between the temperature sensor and the smallest narrow opening of the shell; and a heat resistance breaking space is arranged between the temperature sensor and the shell.

[0020] Compared with the prior art, the temperature sensor has the following advantages after the above technical scheme is adopted.

[0021] The temperature sensor has the following advantages after the above technical scheme is adopted.

[0022] The temperature sensor has the following advantages after the above technical scheme is adopted. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 is a structure schematic view of a temperature sensor of example 1;

[0024] Figure 2 is a cross-sectional schematic view of Figure 1

[0025] Figure 3 is a structure schematic view of a temperature sensor of example 1 after an electromagnetic shielding layer is added;

[0026] Figure 4 is a structure schematic view of a temperature sensor of example 2;

[0027] Figure 5 is a structure schematic view of a temperature sensor of example 2 after an electromagnetic shielding layer is added;

[0028] Figure 6 is a structure schematic view of a temperature probe of example 3;

[0029] Figure 7 is a use state view of the temperature probe of example 3.

[0030] ​In the figure, 1-thermal chip, 11-electrode; 2-wire, 21-thermal resistance section, 22-conversion interface; 3-flexible insulating substrate; 4-insulating cover film; 5-electromagnetic shielding layer; 6-sealing glue; 7-thermal resistance space; 8-housing, 81-limiting mesa; 9-temperature sensor; 100-temperature probe; 101-test tube; 102-sample; 103-cavity. DETAILED DESCRIPTION

[0031] In order to have a clearer understanding of the technical features, purposes and effects of the present application, the specific embodiments of the present application will be described with reference to the accompanying drawings.

[0032] Example 1: A temperature sensor for milk freezing point instrument

[0033] As Figures 1-3 The utility model provides a temperature sensor for milk freezing point instrument, including flexible insulating substrate 3 and insulating cover film 4, the sealed insulating space that is formed between flexible insulating substrate 3 and insulating cover film 4 tightly, be equipped with thermal chip 1 and the wire 2 of one end with thermal chip 1 connection in sealed insulating space.

[0034] Flexible insulating substrate 3 and insulating cover film 4 are tightly combined as a whole by hot pressing process.

[0035] Two conversion interfaces 22 of wire 2 extension respectively have two, two conversion interfaces 22 are according to the interface requirement and set up the switching disc surface of different functional requirements, near thermal chip 1 one end is the welding disc surface, is used for welding thermal chip 1 on-off circuit, the other end is gold finger needle and can be adapted with standard connector, improves general ability.

[0036] Wire 2 near thermal chip 1 one end is provided with the thermal resistance section 21 of obviously narrowing cross section. Thermal resistance section 21 is obtained by calculating impedance, heat conduction capacity, is used for limiting heat conduction, and the parameter design of thermal resistance section 21 also needs to consider the resistance parameter of thermal chip 1 to satisfy more electrical indexes.

[0037] Wire 2 is arranged at a certain electrical distance, and the number of wire 2 is the same as the number of electrode 11 of thermal chip 1.

[0038] The insulating cover film 4 of the conversion interface 22 position of wire 2 away from thermal chip 1 is provided with an opening, and the opening is used for circuit switching conduction to facilitate the transmission of electrical signals outward.

[0039] The width of the flexible insulating substrate 3 and the insulating cover film 4 at the end of the thermal chip 1 is narrowed, and the width is slightly larger than the maximum width of the wire 2 and the thermal chip 1. The extremely narrow width can also reduce the heat conduction space. The insertion depth of the thermal chip 1 should be lower than the height of the thermal resistance section 21 during use of the sensor to achieve the best effect.

[0040] The flexible insulating substrate 3 and the insulating cover film 4 in the embodiment are thin sheets with a thermal conductivity less than 0.2 W / (m·K) and a thickness less than or equal to 50 μm, and have good electrical insulation performance, mechanical flexibility, heat resistance and chemical stability. The material is one of PI, PET, PEN (Polyethylene Naphthalate), PTFE, LCP (Liquid Crystal Polymer) and PPS, and is preferably a PI film.

[0041] The material of the wire 2 is preferably a calendered copper foil with a thickness less than or equal to 1 oz. The thermal resistance section 21 has a cross-sectional area less than 0.0016π mm2 and a length greater than or equal to 1 mm.

[0042] The flexible insulating substrate 3 is provided with an electromagnetic shielding layer 5 on the side away from the wire 2. The electromagnetic shielding layer 5 is kept at a certain distance from the thermosensitive chip 1 to reduce the adverse effects of heat conduction of the electromagnetic shielding layer 5.

[0043] The embodiment can effectively reduce the external heat transfer of the wiring, reduce the heat capacity dead volume, and make the temperature measuring part less susceptible to external temperature, and correspondingly faster and more accurate. The self-resistance of the ultra-fine and ultra-thin copper foil wire can reach several Ω, but it is much smaller than the resistance of the thermosensitive chip 10 kΩ~100 kΩ. The use of the PI film improves the mechanical strength and structural flexibility of the wire, and the ultra-thin size is also more conducive to subsequent secondary development and production. The increased electromagnetic shielding layer can enhance the electromagnetic protection capability and reduce interference.

[0044] Embodiment 2: A temperature sensor for a milk freezing point instrument

[0045] As shown in Figure 4 and Figure 5 The utility model provides a kind of temperature sensor for a milk freezing point instrument, and the difference between embodiment 2 and embodiment 1 is that:

[0046] In embodiment 1, the flexible insulating substrate 3 and the insulating cover film 4 form a sealed insulating space, and the sealed insulating space is provided with a thermosensitive chip 1 and a wire 2 connected to one end of the thermosensitive chip 1. In embodiment 2, the sealed insulating space between the flexible insulating substrate 3 and the insulating cover film 4 is provided with a wire 2, and one end of the wire 2 is connected to a thermosensitive chip 1 outside the sealed insulating space.

[0047] The wire 2 is provided with a conversion interface 22 at both ends, and the insulating cover film 4 is provided with an opening at the position of the conversion interface 22 to allow the transmission of electrical signals to the outside through the conversion interface 22. The conversion interface 22 near the thermal resistance section 21 is bonded with a glass-sealed thermosensitive chip 1.

[0048] In the embodiment 2, the welding disc surface of the lead wire 2 close to one end of the thermosensitive chip 1 is exposed, so that the thermosensitive chip 1 is more convenient to replace, and the embodiment 2 is more flexible than the comparative embodiment 1.

[0049] Embodiment 3: A temperature probe for milk freezing point apparatus

[0050] As Figure 6 shown, the utility model provides a temperature probe for milk freezing point apparatus, temperature probe 100 includes temperature sensor 9, shell 8 and sealant 6.

[0051] Temperature sensor 9 is any one structure of embodiment 1 or embodiment 2.

[0052] The both ends of shell 8 are provided with openings in the extension direction, shell 8 is gradually narrow annular shell shape, and limiting mesa 81 is arranged on the periphery of shell 8 for limiting the depth of temperature probe 100 inserted into test tube 101. Shell 8 is made of low thermal conductivity material with a thermal conductivity less than 0.5 W / (m·K).

[0053] Temperature sensor 9 penetrates the two openings of shell 8, and the temperature measuring part of temperature sensor 9 is out of the smallest narrow opening of shell 8.

[0054] Sealant 6 is low thermal conductivity sealant, and sealant 6 is filled in the gap between temperature sensor 9 and the smallest narrow opening of shell 8. Low thermal conductivity sealant 6 seals and insulates temperature sensor 9 and shell 8, and both are integrated. Sealant 6 is only filled in a small area of the head of the lead wire thermal resistance breaking section, and most of the thermal resistance breaking section is left for heat resistance. In addition, the other end of the lead wire and the opening position of shell 8 can also be fixed by dispensing glue, to increase the adhesion and fastening degree of the lead wire.

[0055] Thermal resistance breaking space 7 is arranged between temperature sensor 9 and shell 8.

[0056] As Figure 7 shown, when temperature probe 100 is inserted into test tube 101 and the depth is limited by limiting mesa 81, the temperature measuring part of temperature probe 100 is deep into the middle of sample 102, and heat insulation cavity 103 is formed in the upper part of test tube 101, which combines the narrow and thin end of the shell, the internal thermal resistance breaking section and the cavity in the shell to block the internal and external temperature, so that temperature probe 100 can only be affected by the temperature of the sample and is not affected by the external temperature.

[0057] The above is the example of the best implementation mode of the utility model, wherein the parts not described in detail are the common knowledge of ordinary skilled in the art. The protection scope of the utility model is subject to the content of the claims, and any equivalent transformation based on the technical inspiration of the utility model is also within the protection scope of the utility model.

Claims

1. A temperature sensor for a milk freezing point apparatus, characterised in that: The temperature sensor comprises a flexible insulating substrate (3) and an insulating cover film (4), the flexible insulating substrate (3) and the insulating cover film (4) are tightly adhered to form a sealed insulating space, a wire (2) is arranged in the sealed insulating space, one end of the wire (2) is connected with a thermosensitive chip (1), and a thermal resistance section (21) with a narrowed cross section is arranged at the end of the wire (2) close to the thermosensitive chip (1). The thermal resistance section (21) has a cross-sectional area less than 0.0016π mm2 and a length greater than or equal to 1 mm. The flexible insulating substrate (3) and the insulating cover film (4) at the end of the thermosensitive chip (1) are in a narrowed state, and the flexible insulating substrate (3) and the insulating cover film (4) are thin sheets with a thermal conductivity less than 0.2 W / (m·K). The flexible insulating substrate (3) is provided with an electromagnetic shielding layer (5) on the side away from the wire (2).

2. The temperature sensor for a milk freezing point apparatus according to claim 1, characterized by: The thermosensitive chip (1) is located inside the sealed insulating space.

3. The temperature sensor for a milk freezing point apparatus according to claim 1, characterized by: The thermosensitive chip (1) is located outside the sealed insulating space.

4. The temperature sensor for a milk freezing point apparatus according to claim 1, wherein: The wire (2) extends to two ends, each of which has two conversion interfaces (22), the two conversion interfaces (22) close to one end of the thermosensitive chip (1) are welding disc surfaces, and the other ends are gold finger pins; the wire (2) is arranged at a certain electrical distance, and the number of the wire (2) is the same as the number of electrodes (11) of the thermosensitive chip (1).

5. Temperature probe for a milk freezing point apparatus, characterized in that: The probe comprises the temperature sensor according to any one of claims 1-4.

6. The temperature probe for a milk freezing point apparatus as claimed in claim 5, characterized in that: Further comprising a shell (8) and a sealing glue (6); the two ends of the shell (8) in the extending direction are provided with openings, the shell (8) is a gradually narrowed annular thin shell, and a limiting table (81) is arranged on the periphery of the shell (8).

7. The temperature probe for a milk freezing point apparatus as claimed in claim 6, characterized in that: The temperature sensor penetrates the two openings of the shell (8), and the temperature measuring part of the temperature sensor penetrates out of the smallest narrowed opening of the shell (8); the sealing glue (6) is filled in the gap between the temperature sensor and the smallest narrowed opening of the shell (8); and the temperature sensor (9) and the shell (8) are provided with a thermal resistance space (7).

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